Progress on perovskite photodetectors for optical communications

Abstract

Optical communication has emerged as a pivotal wireless technology for next-generation information transmission, with photodetectors serving as core components that determine the overall system performance. Perovskite photodetectors stand out as promising candidates, attributed to their exceptional optoelectronic properties and low-cost fabrication. In this review, we systematically summarize the key characteristics of perovskite materials and the essential performance metrics of photodetectors. It further elaborates on the latest advances in the design and fabrication of perovskite photodetectors, encompassing device engineering, dimensional control, and large-scale array integration. Furthermore, the cutting-edge applications of perovskite photodetectors in optical communication scenarios are comprehensively discussed, along with an in-depth analysis of their current challenges and potential development directions. This review aims to provide a comprehensive overview of the progress in perovskite photodetectors for optical communications and offer valuable insights for the rational design and future advancement of high-performance photodetector technologies.

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Jingna Ren

Jingna Ren received her Master's degree from the University of Science and Technology Beijing (USTB) in 2025. Her research focuses on the microstructure design, controlled fabrication, and performance optimization of high-performance perovskite photodetectors.

Boyu Wan

Boyu Wan received his Master's degree from the University of Science and Technology Beijing (USTB) in 2024. Now he is a Ph.D. student at the Academy for Advanced Interdisciplinary Science and Technology in USTB. His research interests focus on the innovative design of perovskite solar cells.

Haonan Si

Haonan Si received her Ph.D. degree from the University of Science and Technology Beijing (USTB). Now she is an associate professor at the Academy for Advanced Interdisciplinary Science and Technology in USTB. Her research interests mainly focus on low-dimensional semiconductor materials and devices.

Qingliang Liao

Qingliang Liao received his Ph.D. degree from the University of Science and Technology Beijing (USTB). Now he is a professor at the Academy for Advanced Interdisciplinary Science and Technology in USTB. His scientific interests focus on the synthesis and characterization of low-dimensional nanomaterials, design, and the application of functional nanodevices.

Yue Zhang

Yue Zhang is a professor at the University of Science and Technology Beijing (USTB), an Academician of the Chinese Academy of Sciences and an Academician of the World Academy of Sciences. His research focuses on functional nanomaterials and nanodevices, new energy materials, and nanoscale failure and service behavior. He has published more than 500 SCI papers in peer-reviewed scientific journals and 13 monographs, and held 100 patents in his research area. His publications have been cited more than 10 000 times by peers.

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1. Introduction

With the rise of wireless communication networks and the growth of mobile devices, optical wireless communication techniques have attracted great attention due to their ultrahigh transmission rates, safety, low error rates, and low cost.^1,2 In addition, visible optical communication technology provides abundant spectrum resources and solves the problems of high energy consumption and spectrum resource shortage faced by traditional radiofrequency communication technology.³ As a key component of optical communication systems, the performance of photodetectors (PDs) directly affects the transmission speed and transmission capacity.^4–7

As the critical functional component in photodetectors, the photophysical properties of photosensitive materials directly govern the performance ceilings and operational mechanisms of the devices. Traditional inorganic photodetector materials, such as silicon and gallium arsenide, possess high mobility and mature processing systems, and have become the mainstream materials for commercial photodetectors. Compared with inorganic photodetectors, solution-processable organic photodetectors exhibited attractive characters including being lightweight, transparent, flexible and non-cryogenic. Organic–inorganic hybrid perovskites (OIHP), concurrently, have attracted significant attention in recent years due to their excellent photovoltaic properties. The solution-processability of perovskites significantly reduces the manufacturing complexity and production costs.⁷ More importantly, perovskites have higher light capture capabilities and upper limits for carrier mobility, as well as more diverse bandgap control methods. These advantages make perovskites suitable for a wider range of optical communication applications.^8–11 Ongoing study in this area focuses on materials synthesis, device structure design, and interface engineering to enhance device properties such as stability, sensitivity, and response speed.¹² So far, photodetectors on the basis of various component different dimensional perovskite materials including 0D nanocrystals (NCs)¹³ and quantum dots (QDs),¹⁴ 1D nanowires (NWs),¹⁵ and nanorods (NRs),^16,17 2D nanosheets (NSs),¹⁸ and large-scale arrays, have been reported successively. However, a comprehensive review systematically connecting hierarchical mechanisms – from microscopic configurations through perovskite optoelectronic properties to photodetector performance metrics and applications – remains conspicuously absent for perovskite-based photodetectors, which impedes high-efficiency performance enhancement research and the development of multifunctional applications.

Herein, we systematically outline the recent advancements in perovskite photodetectors and establish rigorous mechanism linkages – from microscopic configurations of perovskites to their intrinsic optoelectronic properties – subsequently determining photodetector performance metrics, and ultimately possible application domains. A concise overview of performance parameters utilized for PD characterization is provided, followed by component and carrier dynamics, while concurrently integrating their linkages to the intrinsic light absorption range and carrier-transport performance of perovskite materials. Moreover, various structure types of photodetector are systematically investigated, and latest research advances in perovskite photodetectors across diverse compositional variants, morphological dimensionalities, and large-scale array architectures, meanwhile summarizing their respective merits and constraints. Multiple novel optical communication applications of perovskite photodetector are concluded finally. This review summarizes the most recent research findings and provides insights into prospects to contribute to the ongoing discussion and encourage further breakthroughs in perovskite optical communication systems.

2. Fundamentals of PDs

In recent years, both academia and industry have witnessed rapid developments of detector technologies based on emerging photosensitive materials.¹⁹ For accurately capturing the key performance merits of detectors, the optoelectronic performance can be evaluated by several quantitative parameters. The major performance parameters to describe the characteristics of detectors can be divided into optical absorption and photoelectric conversion processes.¹² More specifically, the photoelectric conversion process is governed by three critical performance metrics: signal intensity, conversion efficiency, and detection sensitivity. As critical components in optical communication systems, photodetectors can influence the key performance characteristics that fundamentally dictate overall system functionality. When photodetectors are deployed in optical communication systems, three transmission characteristics are being valued: bit error rate (BER), data transmission rate, and coverage range. Here, we dissect the material and device-level determinants of photodetector performance, and establish mechanistic links to optical communication metrics, as shown in Fig. 1 and Table 1.

Table 1 Common parameters, units and equations of photodetectors

Parameters	Unit		Equation
Linear dynamic range (LDR)	dB		J upper is the maximum current density deviating from linearity, Jlower is the minimum current density in the linear range
Responsivity (R)	A W^−1		J p is photocurrent density, Jd is dark current density, Pλ is the power density of irradiated light and S is the effective exposure area
External quantum efficiency (EQE)	%		h is the Planck constant, ν is the frequency of incident light, which can also be described by c/λ, and e is the absolute value of electric charge
Response time (τrise/τfall)	s		f c is the optical modulation frequency
Bandwidth (f−3 dB)	Hz		τ tr is the carrier transit time and RC-time is the resistance–capacitance time constant of the circuit
Noise equivalent power (NEP)	W Hz^−1/2		i n is the noise current
Detectivity (D*)	cm Hz^1/2 W^−1 (Jones)		A is the active area of the PDs, Δf is the electrical bandwidth, and in is the noise current
On/off ratio	Unitless		I photo is the photocurrent and Idark is the dark current
Gain (G)	Unitless		τ lifetime is the carrier lifetime, d is the carrier transport distance or channel length, μ is the carrier mobility, and V is the bias applied to the device

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Fig. 1 Key performance parameters of a photodetector and its connection to optical communication.

2.1. Light absorption

Given the inevitable signal attenuation arising from Rayleigh scattering and material absorption in long-haul optical communication,²⁰ the photodetector's optical absorption performance critically governs carrier conversion dynamics and transmission fidelity. Linear dynamic range, spectral response range and spectral resolution are three main factors to determine light absorption performance. Enhanced optical absorption can directly elevate the photodetector's sensitivity, thereby extending the maximum achievable coverage range and improving the bit error ratio of optical communication.

2.1.1. Linear dynamic range (LDR). LDR is a crucial figure-of-merit for photodetectors to describe the light intensity range in which the photogenerated current displays a linear dependence on the incident light intensity, and reflecting photodetectors have a constant spectral responsivity in the light intensity range. A large LDR is indispensable for image sensors because the accurate intensity of the optical signal needs to be achieved from the photogenerated current within a wide range of light intensity, which is beneficial to capture images with high fidelity.

2.1.2. Spectral response range. For perovskite photodetectors, the different response wavelengths boost the different applications of devices.²¹ In particular, the wide spectral response facilitates the full-spectrum detection of perovskite photodetectors. The energy of the response wavelength of the device is usually larger than the band gap of the perovskite material, and its spectral response range can be defined as the wavelength that the detector can detect.

2.1.3. Spectral resolution. For perovskite photodetectors, miniaturized and integrated photodetectors with high spectral resolution are necessary because of their wide application in the optoelectronics fields. The spectral resolution can be defined as the minimum full width at half maximum of the reconstructed spectrum for perovskite photodetectors.

2.2. Signal intensity

The intensity of the optical signal generated by the photodetector forms the critical foundation for optical communication reliability.²² The intensity is governed jointly by the photodetector material's responsivity (R) and external quantum efficiency (EQE). Higher signal intensity typically yields greater signal-to-noise ratio (SNR), enhancing resistance to noise and consequently reducing the bit error rate (BER) in optical data transmission. Conversely, insufficient signal intensity markedly increases BER and potentially causes communication failure.

2.2.1. Responsivity (R). Responsivity is defined as the photocurrent per unit power generated by incident light on the effective area of the photodetector per unit time. Responsivity is a crucial parameter to quantify the response efficiency of the photodetector to the optical signal. It is related to the external quantum efficiency (EQE).

2.2.2. External quantum efficiency (EQE). EQE is defined as the ratio of the number of output photogenerated carriers to the number of incident photons under a specific wavelength radiation. EQE reflects the photon–electron conversion efficiency of the whole detector, and depends on both the light absorption and the charge collection.

2.3. Conversion rate

The signal conversion rate directly determines the maximum optical signal modulation frequency that a photodetector can track, constituting a critical bottleneck limiting the data transmission rate of the entire optical communication system.²³ This rate is primarily governed by response time (τ_rise/τ_fall) and bandwidth (f_{−3 dB}), influenced collectively by bulk defects within the detector, carrier lifetime, device architecture design, and the bandwidth of subsequent amplification circuits. The photodetector's conversion rate defines the theoretical upper limit for the maximum transmission rate in optical communication systems, forming an essential prerequisite for achieving high-speed data transmission.

2.3.1. Response time (τ_rise/τ_fall). The response time generally refers to the speed of response of a device and consists of a rise time (τ_rise) and a fall time (τ_fall). τ_rise can be evaluated by the time the photocurrent rises from 10% to 90% of the maximum current value, and τ_fall can be evaluated by the time the photocurrent falls from 90% to 10% of the maximum current value. The speed of the response time is related to the capture and removal of photogenerated charges, as well as to the quality of the contact between the interfaces in the device. In addition, the response time can be optimized by optimizing the thickness and mobility of the active layer and the applied voltage.

2.3.2. −3 dB bandwidth (f_{−3 dB}). The bandwidth of the detector is defined as the optical modulation frequency f_c with the response attenuation of 3 dB.²⁴ According to the relationship between τ_tr, RC, and f_{−3 dB}, the shorter the RC time constant is, the faster the response speed, and a higher sensitivity of photodetectors will be obtained.

2.4. Sensitivity

When the photodetector is functioning, the output current and voltage signals are fluctuating randomly with time. The random fluctuation part of the photodetector output is called “noise”, which is independent of the incident radiation statistics. The device detectivity is the comprehensive sum of the signal intensity and noise; it represents the sensitivity of the device, and ultimately governs the bit error rate (BER) in optical communication systems.²⁵ In this section, we introduce the noise current (i_n) along with the noise-equivalent power (NEP) and detectivity (D*), both directly determined by noise characteristics. Additionally, we discuss how the on/off ratio and photoconductive gain (G) contribute to the photodetector sensitivity.

2.4.1. Noise current (i_n). The noise of photodetectors consists of thermal noise, granular noise and flicker noise. In general, the thermal noise is caused by the movement and separation of carriers generated by heat excitation inside the semiconductor material. The scatter-particle noise is the current signal disturbance caused by random carriers passing through the detector. The 1/f noise is generated when the carrier is trapped by the defect or escapes from the defect during the migration process.

2.4.2. Noise equivalent power (NEP). NEP is defined as the optical power of incident light when the signal-to-noise ratio (SNR) is 1 over a bandwidth of 1 Hz, indicating the smallest optical power that can be recognized by a photodetector from the noise. NEP measures the ability of a photodetector to receive weak signals, and the smaller the NEP, the better the performance of the detector. It is the smallest target radiation that a detector can detect, marking the sensitivity of a detector.

2.4.3. Specific detectivity (D*). D* is determined by the responsivity and noise of a photodetector. D* is a very important performance parameter used to appraise the detection sensitivity of a photodetector, which is inversely proportional to NEP. D* is used to characterize the weakest light intensity that can be detected by the light detector, showing the detection capability of a PD for weak light.

2.4.4. On/off ratio. The light-to-dark current ratio (or on/off ratio) is defined as the ratio of the light current to the dark current (I_photo/I_dark). The on/off ratio reflects the photosensitivity of photodetectors. Some articles also use the ratio of the photogenerated current to the dark current (ΔI/I_dark) to express the light-to-dark current ratio. Generally, the light-to-dark current ratio is affected dramatically by the incident light intensity and wavelength.

2.4.5. Gain (G). Gain is defined as the number of charge carriers travelling through an external circuit per incident photon. Both G and response time are dependent on τ_lifetime, and hence the two properties must be balanced. High photoconductive gain maximizes sensitivity.

3. Halide perovskites for PDs

Emerging halide perovskite materials are gradually becoming one of the ideal candidates for next-generation optoelectronic detection technologies due to their complementary advantages compared with traditional materials (Si, ZnO, GaN, etc.).²⁶ The structure of interconnected cubes or octahedra endows the perovskite materials with outstanding electrical and optical properties.²⁷ More specifically, they exhibit high carrier mobility, excellent light absorption, and tunable energy band gaps, making them highly desirable for photoelectric conversion devices. As the performance of perovskite-based photodetectors continues to improve, a good understanding of their light-absorbing principle and carrier transport dynamics is crucial for the further development and optimization of perovskite photodetectors. In this section, we detail the influence of A, B and X site ionic configurations on the light absorption range and the determinative role of carrier dynamics in charge-transport performance.

3.1. Light absorption range

One of the main advantages of perovskites is the wide light absorption range, which is determined by the basic structure. The chemical formula for 3D metal halide perovskites is categorized as ABX₃, where the A site is occupied by cations such as Cs⁺ and MA⁺.^28,29 The B site represents divalent cations, such as Pb²⁺, Sn²⁺, and Ge²⁺, while X denotes halides such as I⁻, Br⁻ and Cl⁻, as illustrated in Fig. 2a. A-site atoms occupy cubic octahedral cavities to form the framework, and the B-site atoms and X-site anions form the [BX6⁴⁻] octahedra. Commonly, the tolerance factor:where R_A, R_B and R_X represent the ionic radii of different ions. The tolerance factor is used to estimate the effects of ionic radii on crystal structure. To maintain a stable crystal structure, t must be restricted between 0.8 and 1.0, as shown in Fig. 2a (taking APbI₃ as an example). The influence of the A, B, and X sites on the perovskite's intrinsic properties and the performance of perovskite photodetectors is detailed below.

Fig. 2 (a) Perovskite structure and optical absorption governing through A, B, and X site engineering. (b) Band structure and optical response characteristics of perovskites with different compositions.

3.1.1. A-site cations. The A-site cations (e.g., MA⁺, FA⁺, Cs⁺) primarily govern the structural stability and phase transition behaviour, while indirectly modulating the bandstructure.^30,31 Larger FA⁺ ions expand the lattice, inducing a marginal bandgap narrowing (e.g., 1.48 eV for FAPbI₃versus 1.55 eV for MAPbI₃) and a concomitant red-shift in the absorption onset (λ_max ≈ 840 nm). Conversely, smaller Cs⁺ ions enhance thermal stability but slightly increase the bandgap. Employing mixed A-site cations (e.g. FA/Cs) synergistically suppresses non-photoactive phase transitions (e.g. the δ-phase in FAPbI₃), stabilizing the cubic structure for a broad-spectrum response. This approach simultaneously optimizes the bandgap position through subtle lattice tuning, thereby balancing absorption edge coverage and operational stability. Furthermore, substituting A-site cations with large organic molecules at specific ratios can transform the 3D perovskite architecture into 2D.³² The 2D crystal lattice, (A′)m(A)_n−1B_nX_3n+1, adopts a new structural and compositional dimension, A′, where monovalent (m = 2) or divalent (m = 1) cations can intercalate between the anion 2D perovskite sheets. Besides its apparent simplicity, the concept of dimensional reduction not only grants access to a plethora of hybrid organic–inorganic materials with tailorable functionalities, but also gives rise to an unparalleled structural complexity which allows for the fine-tuning of the optoelectronic properties. 2D perovskite crystals can be regarded as n layers of [MX₆]⁴⁻octahedral sheets sandwiched by two layers of large organic spacer cations, giving rise to natural multiple-quantum-well structures, in which the inorganic slabs serve as the potential “wells” while the organic layers function as the potential “barriers”. The generated excitons are therefore confined within the inorganic slabs, and when combined with the low dielectric screening from the surrounding organic spacers, much larger exciton binding energies (E_b) are obtained than those of their 3D counterparts. Such quantum confinement effect decreases with increasing “well” thickness (n), which can be incrementally tuned by a cautious control of the precursors’ stoichiometry.

3.1.2. B-site metal ions. B-site metal ions (e.g., Pb²⁺, Sn²⁺) directly govern the bandgap magnitude and absorption range. The 6s/p orbitals of Pb²⁺ yield a bandgap of ≈ 1.55 eV (MAPbI₃), setting the absorption onset near 800 nm.³³ In contrast, the higher energy 5s orbitals of Sn²⁺ significantly elevate the valence band maximum, reducing the bandgap to 1.2–1.4 eV (e.g., FASnI₃) and red-shifting the absorption into the 950–1050 nm near-infrared (NIR) region. However, the pronounced susceptibility of Sn²⁺ to oxidation necessitates synergistic A-site encapsulation or X-site halide engineering to preserve structural integrity and ensure stable broad-spectrum photodetection.

3.1.3. X-site halides. X-site halides (I⁻, Br⁻, Cl⁻) mediate the bandgap and absorption onset through fine-tuning of the valence band maximum (VBM). The high-energy 5p orbitals of I⁻ form an elevated VBM, resulting in a narrow bandgap (e.g., 1.55 eV for MAPbI₃). Conversely, the lower-energy 4p orbitals of Br⁻ depress the VBM, widening the bandgap to 2.3 eV (MAPbBr₃) and blue-shifting the absorption edge to 540 nm. Controlled mixing of I/Br enables continuous bandgap engineering (1.55–2.3 eV), allowing precise tailoring to specific spectral regimes (e.g., ≈ 1.7 eV bandgap with 20% Br doping, extending the response to 730 nm). However, this necessitates suppression of photoinduced phase segregation to maintain spectral stability under operational conditions.³⁴

In perovskite materials (general formula ABX₃), the elemental composition at the A, B, and X sites critically determines the crystal structure, bandgap, electronic band structure, and ultimately the light-harvesting characteristics of photodetectors.

3.2. Charge transport performance

Another advantage of perovskites is the elevated charge transport performance, which is determined by carrier dynamics. The dynamic parameters of perovskite carriers impact the properties of photodetectors.^35,36 This section outlines the fundamental mechanisms of carrier generation, migration, and recombination. We then examine the influence of carrier mobility, carrier lifetime, and recombination dynamics on the performance characteristics of perovskite photodetectors.

Perovskite charge carriers are free charge carriers primarily consisting of electrons and holes.³⁷ Energy transfer triggered by photoexcitation or an electric field can cause electrons to transition from the valence band to the conduction band, thus generating free electrons and holes. The mechanism of the generation of these charge carriers is vital to the carrier dynamics in perovskite materials. In perovskite materials, electrons and holes recombine and release energy.^38–40

When materials absorb photons, the photon energy causes electrons in the valence band to transition to the conduction band and form electron–hole pairs.⁴¹ Electrons are excited to the conduction band and become free electrons that can migrate freely in the materials, whereas holes in the valence band lead to positively charged carriers, as shown in Fig. 3a. This process excites electrons from the valence band to the conduction band, so perovskite materials can conduct electricity and participate in photoelectric conversion. However, in some cases, the transitioned electrons and holes remain in the form of “excitons” that attract each other through Coulomb forces. Excitons are bound states of electrons and holes that cannot move freely. Only under sufficient energy offset and external electric fields will they efficiently separate into free carriers. The electrons and holes move from their generation sites to the heterojunction interfaces, e.g., bulk heterojunction or planar heterojunction, and are collected by the electrodes to generate the photocurrent. The migration mechanism involves carrier mobility and diffusion. A high carrier mobility enables rapid movement in the materials to improve the device performance, whereas a longer diffusion length allows for a more effective collection of photogenerated carriers to improve the photoelectric conversion efficiency. More specifically, the carrier lifetime determines the distance photogenerated carriers can travel before recombination, thus affecting the response speed and sensitivity. A long carrier lifetime improves the gain and responsiveness of a photodetector, but an excessively long lifetime may produce a slower response. The carrier mobility affects the carrier transport efficiency, and high mobility improves the response speed and current output of the photodetector.

Fig. 3 (a) Charge carrier dynamics: generation, migration, and recombination mechanisms. (b) Defect states band structure schematic. (c) Connection of charge migration and photodetector performance.

The recombination influences the photoelectric properties of the materials and determines the lifetime of charge carriers. Charge-carrier recombination in perovskites occurs by several mechanisms, including radiative, nonradiative, Auger, and surface recombination. Nonradiative recombination is the primary pathway for carrier relaxation and leads to reduced photoluminescence quantum efficiency.^42,43Fig. 3a and b shows the recombination pathways of charges (electrons and holes) in a photodetector. As can be seen, in an ideal structure after photoexcitation, the electrons from the ground state at the VBM will be activated into excited states at the conduction band minimum (CBM) and simultaneously form free charges.^44,45 The free charges are transported within the semiconductor, transfer out through the interface, or recombine via band-to-band recombination. This process is intrinsic, often occurs at a location where no defects are present, and results in the photoluminescence (PL) phenomenon. Since it directly relates to the reverse process of light absorption, the “band-to-band” radiative recombination process does not significantly depend on the defect levels of the perovskite. Actually, the energy difference between the photoexcited free electrons and holes is the origin of the open-circuit voltage (V_OC) of the PSCs. Therefore, the “band-to-band” radiatively recombined charges should be significantly preserved in the perovskite. Because defects will insert an energy transition level within the band gap of the semiconductor, however, the presence of a defect could trap the free charges and greatly change the charge recombination pathways and influence the optoelectronic process. During the transportation of the free charges, a part of the free charges is likely to be captured or trapped by the defects. Such a process breaks the ideal photophysical properties of perovskites, thereby reducing the optoelectronic properties of the PSCs. The charges trapped by the defects with different energy levels have different types of behaviour. Shallow-level defects are not a severe problem for a perovskite.⁴⁶ In the case of MAPbI₃, despite the detrapping of charges captured by shallow-level defects, even if radiative recombination assisted by shallow-level defects is by far the most dominant process, the recombination rate can be very high without compromising the performance of PSCs. This is because the emitted photons would probably be reabsorbed by the perovskite. However, deep-level defects are the origin of the non-radiative recombination process, and they are the biggest problem. For perovskites, the dynamics of charge recombination is closely correlated with the depopulation rate of the charges on defects and with the defect density. The deep-level defects in a perovskite are considered to be the major non-radiative recombination centre that eliminate the charges and limit the performance of EQE. The non-radiative recombination process in the perovskite could reduce the steady-state electron/hole density, charge lifetime, and charge diffusion length, thereby leading to a severe loss of charge transport performance.

Having established the fundamental mechanisms governing light absorption and charge transport, we now undertake a comparative analysis between perovskites and traditional semiconductor materials. Comparative analysis reveals distinct advantages and limitations of perovskites relative to conventional semiconductors, as shown in Fig. 4. Perovskites exhibit a superior light-absorption range and enhanced charge-transport properties, which underpin exceptional responsivity and detectivity ceilings in photodetector architectures. However, operational stability constraints present ongoing challenges for practical device implementation.

Fig. 4 Advantages and disadvantages of traditional semiconductors and perovskites.

4. Structures of perovskite PDs

This section provides a systematic analysis of three primary perovskite photodetector architectures: photoconductors, photodiodes, and phototransistors, categorized based on their distinct operational mechanisms. Furthermore, these devices can be classified into lateral and vertical configurations according to their spatial layer arrangements. The detailed architectures and working principles fundamentally govern the charge carrier transport dynamics and interfacial phenomena observed in each detector type, which subsequently determine their respective performance merits and limitations.^30,44 The interplay of these structural and operational differences constitutes key determinants of the varied photodetection performance across device configurations, spanning multiple aspects including responsivity, response speed, and noise suppression characteristics, among others.⁴⁷

4.1. Photoconductors

Photoconductive devices typically adopt a fundamental configuration, including the perovskite absorber and two Ohmic metal contacts, which operate by applying an external bias to generate photoconductive gain through carrier recirculation. Upon absorption of photon energy exceeding or matching the material's bandgap, valence band electrons undergo photoexcitation to the conduction band, producing abundant electron–hole pairs. This photoinduced carrier multiplication induces a pronounced conductivity enhancement, yielding a dramatically amplified photocurrent under applied bias voltage, with the photocurrent magnitude exhibiting linear proportionality to the incident light intensity as photoinduced carriers migrate directionally under the applied electric field. Structurally, they are categorized into lateral and vertical configurations based on their electrode arrangements, as shown in Fig. 5. Lateral photoconductors feature planar electrodes separated by millimeter-scale gaps, which require higher applied bias voltages and prolonged response times owing to their elongated carrier migration distances. In contrast, vertical photoconductors minimize electrode spacing through structural optimization, significantly reducing carrier migration paths and consequently demonstrating lower operating voltages and faster response characteristics.⁴⁸

Fig. 5 Device structure and operating mechanism of (a) a lateral type and (b) a vertical type perovskite photoconductor.

Conventional single-layer perovskite photodetectors designed for monochromatic applications continue to exhibit narrow spectral response ranges in optical recognition systems, despite the demonstrated advantages of lateral photoconductive architectures in photocurrent generation and responsivity. This structural limitation becomes critically evident when addressing the growing requirements for real-time multispectral optical data processing. To bridge this functionality gap, research efforts are increasingly focusing on heterostructure integration approaches to enable adaptive multispectral sensing architectures. Liu⁴⁹et al. developed a light-programmable dual-mode photodetector based on CSUCNP/perovskite heterostructures, with the device architecture schematically illustrated in Fig. 6a. The lateral Au electrode configuration facilitated wavelength-dependent charge transport modulation, as evidenced by current–voltage (I–V) characteristics in the dark and in illuminated conditions (Fig. 6b and c). Fig. 6d demonstrates the spectral response tunability, where core–shell UCNP devices achieved optimized performance through synergistic Gd³⁺ doping (5%) and nanostructural engineering. Transient response measurements (Fig. 6f and g) quantified the dynamic behavior, showing rapid sub-20 ms switching under visible light versus slower recovery kinetics under NIR exposure. This kinetic disparity originates from up-conversion-mediated carrier trapping in the core–shell architecture, where trapped carriers require extended recovery time after light withdrawal. These findings collectively demonstrate that Gd³⁺ incorporation simultaneously passivated interfacial defects and modulated carrier lifetimes through nanostructural engineering, establishing a synergistic mechanism for device performance enhancement, achieved a light-programmable dual-mode photodetector.

Fig. 6 (a) Device schematic of the CSUCNP/perovskite hybrid structure with lateral Au electrodes. (b) Current–voltage characteristics in the dark and under dual-wavelength illumination (500 nm/980 nm). (c) Enhanced I–V behavior of core–shell CSUCNP/perovskite devices. (d) Tunable spectral response spanning visible (400 nm) to near-infrared (1100 nm). (e) Photocurrent values of 305 nA (500 nm, 0.47 mW cm⁻²) and −75 nA (980 nm, 50 mW cm⁻²) at 10 V bias. (f) S1 and (g) S5 under 500 nm and 980 nm light illumination. Reproduced with permission.⁴⁹ Copyright 2025 Wiley-VCH GmbH.

Building on the inherent advantages of lateral photoconductors in achieving enhanced photocurrent and responsivity, recent advances have focused on architectural optimization and system integration to enable scalable detector arrays. Li et al.⁵⁰ developed a planar photoconductor based on [(R)-3APr]PbI₄ single-crystalline thin films (SCTFs), which contrasts with the core–shell heterojunction strategy by prioritizing chiral polarization discrimination over spectral-range extension. This planar SCTF configuration integrates high photoresponsivity and polarization sensitivity within a monolithic architecture, establishing single-crystalline thin films as a scalable platform for chiral photodetection.

Photoconductive detectors, characterized by their simplified architecture and pronounced photoconductive gain, deliver substantial photocurrent generation and enhanced responsivity, particularly advantageous for low-intensity optical signal detection.⁴⁸ Nevertheless, these devices inherently exhibit elevated dark current and intrinsic noise floors, alongside response speed limitations imposed by extended carrier transit paths, necessitating elevated operational bias voltages. Within optical communication systems, photoconductive configurations demonstrate potential in low-data-rate, high-sensitivity encrypted communication receivers, yet their inherent temporal response constraints fundamentally restrict implementation in high-speed modulation regimes.

4.2. Photodiodes

The photodiode, as shown in Fig. 7, consists of a bottom electrode, electron transport layer, photoactive layer, hole transport layer, and top electrode. As an optoelectronic device based on the photovoltaic effect, the photogenerated electrons and holes are separated by the built-in electric field formed at the p–n junction, and then transported to their respective electrodes through the corresponding charge transport layers. In contrast to photoconductive detectors, photodiodes enable direct light-to-electricity conversion (generating photovoltaic voltage/current) without requiring an external bias voltage. This operational mechanism eliminates photoconductive gain but ensures fast response times and low dark currents, attributed to the short electrode spacing (<1 μm) that effectively reduces carrier diffusion delays between functional layers.

Fig. 7 Device structure and operating mechanism of the perovskite photodiode.

Guided by this design principle, Hu et al.⁵¹ added inorganic metal oxide electron transport layer (ETL) materials. They constructed a photodetector with a vertical stacked structure (FTO/ETL/perovskite/Spiro-OMeTAD/Ag), the specific ETL materials being TiO₂ and SnO₂. Theoretically, the band energies of the two ETL materials match well with the energy levels of the perovskite film with a type-II band alignment, which provides favorable conditions for the separation and transport of electrons and holes, and enables a self-powered response driven by the built-in electric field without the need for an external power supply. Under 550 nm illumination, there is a rise response time of less than 1 ms and a fall response time of less than 30 ms. In addition, the dark current density and photocurrent density values of the SnO₂-based PPD are 1.5 × 10⁻⁷ A cm⁻² and 1.9 × 10⁻⁴ A cm⁻², respectively, while those of the TiO₂-based PPD are 2.7 × 10⁻⁷ A cm⁻² and 1.1 × 10⁻⁴ A cm⁻². These photodetectors achieve high responses in the ultraviolet A (UVA) (320–400 nm) and visible light (400–600 nm) regions, and better responses can be obtained at wavelengths above 500 nm. The photodetectors fabricated in this work exhibit better photoresponse performance in a wide spectral range of UVA and visible light, providing a new approach to solving the problem of improving the photodetection performance of target thin films.

On the basis of introducing interface layers to endow photodetectors with high detectivity, in order to achieve efficient circular polarization and linear polarization recognition, Wang et al.⁵² fabricated a photodetector device, as shown in Fig. 8a, with a specific structure of ITO/PEDOT:PSS/perovskite /PCBM/Ag. They utilized this device to investigate the performance of the circularly polarized light (CPL) detector in distinguishing the polarization states of left-handed CPL (LCP) and right-handed CPL (RCP) photons, measuring the photocurrents in different directions under CPL illumination with a laser wavelength of 405 nm. They adjusted the thickness of the chiral perovskite film by modifying the concentration of the precursor solution to explore the optimal recognition performance. The recognition effect reached the optimal level when the perovskite thickness was 400 nm. This optimal thickness not only ensures excellent circular dichroism (CD) signals but also promotes carrier transport and enables a relatively large sensitivity factor. As shown in Fig. 8b and c, under the optimal parameter conditions, (R-NEA)PbI₃ and (S-NEA)PbI₃ exhibit significantly different photocurrents under RCP and LCP illumination, indicating their sensitivity to CPL. In addition, the photodetector based on (R-NEA)PbI₃ yields a higher photocurrent under RCP illumination than under LCP illumination of the same light intensity, whereas the photodetector based on (S-NEA)PbI₃ shows the opposite result. Fig. 8d and e present the I–V responses of the two chiral devices in different directions under CPL conditions. With the light intensity maintained constant, there is a significant difference between the photocurrents excited by LCP and RCP, which proves that the device can clearly distinguish the polarization states of RCP and LCP photons. Fig. 8f and g are magnified views of the circular polarization-dependent photocurrent as a function of the rotation angle of the quarter-wave plate (QWP), demonstrating that the device has an effective discrimination capability for CPL. The circularly polarized photocurrent reaches 178 nA at θ = 0° and drops to 157 nA at θ = 90°, which confirms the circular polarization dependence. Fig. 8h shows the photocurrent under different light intensities at a bias voltage of 0 V. The responsivity increases linearly with the decrease of light intensity due to the increase of photoconductive gain. These results not only open up a new path for constructing integrated miniaturized polarization photodetectors but also provide a universal strategy for fabricating self-powered filter-free Stokes detectors based on patterned chiral perovskite films.

Fig. 8 (a) Schematic diagram of the chiral perovskite-based photodetector. (b) I–t curves of (R-NEA)PbI₃ under 405 nm left circularly polarized (LCP) and right circularly polarized (RCP) illumination at 0 V bias. (c) I–t curves of (S-NEA)PbI₃ under 405 nm LCP and RCP illumination at 0 V bias. (d and e) I–V response diagrams of (R-NEA)PbI₃ and (S-NEA)PbI₃ measured with LCP (blue light) and RCP (red light) at a laser wavelength of 405 nm and an intensity of 0.7 mW cm⁻². The insets show the cases at 0 V. (f and g) Magnified views of the photocurrent data under different circular polarization states. (h) Plots of photocurrent and calculated responsivity under different light intensities. Reproduced with permission.⁵² Copyright 2024 Wiley-VCH GmbH.

Photodiode architectures leverage built-in electric fields at p–n junctions to achieve an ultralow dark current and exceptional detection sensitivity, coupled with rapid response kinetics and self-powered operational capability at zero bias.⁵³ Their primary limitations stem from the absence of intrinsic gain mechanisms resulting in moderate responsivity, alongside sophisticated multilayer structures demanding precise interface engineering. For optical communication applications, such devices emerge as preferred candidates for high-speed visible light communication and fiberoptic receiver systems due to their superior temporal response and noise suppression characteristics, with self-powered operation further advancing low-power portable communication technologies.

4.3. Phototransistors

Phototransistors emulate the three-terminal architecture of field-effect transistors by integrating a gate electrode and dielectric layer into the semiconductor channel, combined with conventional source/drain contacts, as depicted in Fig. 9. This mechanism fundamentally differs from transverse-type photoconductors: when charge carriers become immobilized by trapping effects, the gate terminal actively accelerates electron–hole recombination kinetics through electrostatic manipulation, thereby synergistically combining photoconductive gain with gate-modulated conductivity. Gate voltage modulation enables a precise regulation of semiconductor channel properties, dynamically tuning conduction characteristics while suppressing dark currents via carrier depletion. However, their laterally arranged planar configuration typically employs micron-scale channel lengths, necessitating elevated bias voltages to overcome extended carrier transit distances.

Fig. 9 Device structure and operating mechanism of the perovskite phototransistor.

To enhance the response speed while ensuring a high photocurrent, Jiang et al.⁵⁴ fabricated an Al₂O₃/2D perovskite heterostructure and utilized it as the photoactive dielectric for high-performance MoS₂ phototransistors. The results confirm that this heterostructure dielectric enables high-sensitivity photodetection. Similarly, to improve the response speed of photodetectors, Lee et al.⁵⁵ fabricated a perovskite–graphene hybrid photodetector on a SiO₂/Si substrate. The specific structure is shown in Fig. 10a, where the Si wafer and SiO₂ layer serve as the gate and dielectric, respectively. The Si wafer is heavily n-doped, and the SiO₂ layer is thermally grown with a thickness of 300 nm. The silanol groups on SiO₂ are reduced through surface modification with n-octadecyl trimethoxy silane (ODTS), which functions to trap surface charges. Au source/drain electrodes are formed on the substrate by thermal evaporation through a shadow mask, with a channel length of 50 μm and a width of 1000 μm. After transferring the chemical vapor deposition (CVD) grown monolayer graphene onto the substrate, photolithography and plasma etching are performed to pattern the graphene channel. The CH₃NH₃PbI₃ perovskite layer is deposited onto the graphene surface via a one-step spin-coating method. The resulting film exhibits a rough morphology, including segments with a thickness of less than 100 nm (valley regions) and segments with a thickness of up to 480 nm (peak regions). The optical microscope image of the perovskite film on the graphene substrate is shown in Fig. 10b.

Fig. 10 (a) Schematic diagram of the device. (b) Optical microscope image of the CH₃NH₃PbI₃ perovskite–graphene hybrid phototransistor detector. Reproduced with permission.⁵⁵ Copyright 2014 John Wiley and Sons. (c) Material selection for the perovskite layer. (d) Co-solvent engineering for the perovskite precursor. (e) Phase engineering optimization by selecting different annealing temperatures. (f) Multifunctional passivation using organic cations as the interface layer. Reproduced with permission.⁵⁶ Copyright 2023 Wiley-VCH GmbH.

Organic–inorganic halide perovskites’ insufficient mobility and lack of an effective photoconductive gain mechanism often lead to a poor performance of Pb-based perovskite photodetectors. To demonstrate that ZnON/perovskite heterostructures can be used to fabricate high-performance hybrid phototransistors (HPTs), Yun et al.⁵⁶ fabricated a metal oxide/perovskite heterostructure and applied it to high-performance HPTs. Due to its high mobility (>50 cm² V⁻¹ s⁻¹) and ability to facilitate the transport of photogenerated carriers, the ZnON film is used as the metal oxide channel layer of the HPT. However, existing ZnO/perovskite heterostructures usually suffer from interface instability, so it is necessary to select a suitable perovskite light-absorbing layer material. As shown in Fig. 10c, after studying the reactions occurring at the ZnON/perovskite interface, it is finally determined that the multi-cation perovskite FACsPbI₃ meets the requirements. Then, as shown in Fig. 10d, a high-quality FACsPbI₃ film with high crystallinity and a smooth, pinhole-free surface is developed on the ZnON film by forming a Lewis acid–base intermediate phase through solvent engineering. As shown in Fig. 10e, after exploring the reaction between the FACsPbI₃ film and the ZnON film, a more efficient black α-FACsPbI₃ phase is obtained by optimizing the annealing temperature. Finally, as shown in Fig. 10f, a GuI interface passivation layer is introduced into the ZnON/FACsPbI₃ heterostructure. The use of the GuI layer for interface passivation can reduce the defect density on the ZnON surface and in the bulk perovskite, and improve the separation and transport of photogenerated carriers. Through these steps, the HPT based on the ZnON/GuI/FACsPbI₃ heterostructure exhibits an excellent specific detectivity of 1.28 × 10¹⁸ Jones and a response time of 0.1 s. Therefore, the feasibility of using the ZnON/FACsPbI₃ heterostructure for fabricating high-performance HPTs is successfully demonstrated by introducing multi-cation perovskites, co-solvent engineering, phase engineering, and interface passivation. This work provides a new method for the design and fabrication of high-performance metal oxide/perovskite heterostructures.

Phototransistor configurations exploit gate-field modulation to achieve extraordinary gain characteristics and responsivity benchmarks, complemented by active dark current suppression capabilities, demonstrating remarkable detection sensitivity.⁴⁶ However, their response dynamics are fundamentally constrained by gate-induced capacitance effects, while sophisticated device architectures impose stringent fabrication requirements. In optical communication paradigms, these devices offer distinct advantages for signal reception in low-irradiance environments such as underwater and deep-space optical links, with gate-tunable properties enabling novel signal processing functionalities; nevertheless, intrinsic response speed limitations ultimately restrict their deployment in ultra-broadband communication systems.

In conclusion, perovskite-based photodetectors demonstrate distinct performance characteristics across various device configurations, as shown in Fig. 11.⁴⁸ Photoconductor architectures benefit from straightforward fabrication processes and leverage photoconductive gain mechanisms to achieve high photocurrent densities, enhanced R and EQE. However, inherent limitations including elevated dark current, compromised specific detectivity, and increased NEP ultimately limit their precision photodetection capabilities. Among these, vertical-structured photoconductors demonstrate superior operational efficiency in driving the voltage and temporal response through minimized inter-electrode spacing.²⁷ In contrast to gain-based photoconductors, p–n junction-based photodiode architectures strategically incorporate charge-selective electron- and hole-transport layers (ETL/HTL) to substantially suppress dark current and noise while accelerating the charge collection dynamics. The built-in electric field enables efficient separation of photogenerated carriers under low bias conditions, even achieving zero-bias operation. Nevertheless, these improvements are accompanied by inherent compromises, particularly reduced spectral R and moderated EQE compared with photoconductive systems. Phototransistor configurations utilizing three-terminal architectures demonstrate unique advantages by leveraging the gate electrode to modulate channel conductivity and dynamically suppress dark currents. Perovskite-based phototransistors exploit exceptional carrier transport properties to achieve EQE exceeding 100%, enabling ultrahigh photocurrent generation and responsivity values. However, this responsivity enhancement typically occurs at the expense of response speed due to inherent gate capacitance effects, presenting fundamental tradeoffs between sensitivity and temporal resolution in device optimization.

Fig. 11 Schematic illustration of structural in photodetectors and Radar chart comparison of performance metrics across photodetector types.⁶

5. Progress of perovskite PDs

5.1. Component design for perovskite PDs

The exceptional compositional flexibility of perovskite materials establishes component engineering as a critical pathway for optimizing photodetector performance. Through the rational design of A-site cations, B-site metal ions, and X-site halides in the ABX₃ structure, researchers can systematically tune essential optoelectronic properties, including bandgap width, charge carrier mobility, and defect concentration, etc. These engineered parameters directly govern device-level characteristics such as responsivity, temporal response, and noise current levels, thereby underscoring the strategic importance of compositional control in advancing perovskite photodetectors. This section examines recent breakthroughs in component design strategies and their profound impacts on enhancing device functionality and operational stability.⁴⁸

Zhai et al.⁵⁷ employed FA⁺, MA⁺, and Cs⁺ as A-site cations coupled with Br⁻ and I⁻ as X-site anions, fabricating ultrathin perovskite family materials with structural uniformity via a universal low-temperature vapor-phase synthetic route, thereby elucidating profound correlations between compositional engineering strategies and device-level photoresponse characteristics including responsivity and response dynamics. They developed a self-limiting CVD growth strategy for synthesizing large-scale PbBr₂ nanoflakes, as shown in Fig. 12a. Using HABr as a capping agent, they regulated the growth kinetics via a tailored temperature gradient: PbBr₂ precursors were placed in a high-temperature zone, while HABr vapor was introduced through reverse gas flow from a lower-temperature region, enabling precise control over nucleation and nanostructure growth. The nanoflake lateral dimensions depended strongly on temperature. At T₁ = 400 °C, optimal uniformity was achieved, yielding square-shaped PbBr₂ nanoflakes over 500 µm, as shown in Fig. 12b. Extending this method to PbI₂ synthesis, HAI additives facilitated micron-scale flakes exceeding 450 µm, as detailed in Fig. 12c. Notably, reduced growth pressure (100 Pa) was key to enhancing precursor deposition uniformity, producing centimeter-scale PbBr₂ films with smooth, pinhole-free surfaces, as evidenced by Fig. 12d and e. Fig. 12f illustrates the fabrication and characterization of planar photodetectors based on converted MAPbBr₃ nanoflakes, revealing their structural integration with semimetal bismuth (Bi)/gold (Au) electrodes to minimize metal-induced gap states. Fig. 12g displays current–voltage (I–V) characteristics under varying 532 nm light intensities, demonstrating near-ohmic contact behavior with ultralow dark currents and linear photocurrent dependence on voltage. Fig. 12h maps the wavelength-dependent responsivity of MAPbBr₃ devices, showing a broad spectral response between 310–530 nm with peak performance at 532 nm. Fig. 12i quantifies ultrafast photoresponse kinetics, achieving a rise time of 55 μs and decay time of 35 μs, critical for high-speed imaging applications. The comparative analysis in Fig. 12j evaluates FA-based perovskites (FAPbBr₃, FAPbI₃), revealing exceptional photoresponsivity (1.7 × 10³–3.7 × 10³ A W⁻¹) coupled with sub-10 μs response speeds – metrics that surpass those of their MA- and Cs-based counterparts in photodetection performance. Finally, Fig. 12k benchmarks these devices against state-of-the-art perovskite photodetectors, positioning FA-based systems in the high-responsivity, ultrafast-response performance quadrant. This systematic evaluation highlights advances in suppressing ion migration via FA⁺ lattice integration and underscores the role of crystalline quality in achieving excellent responsivity and detectivity metrics.

Fig. 12 (a) Schematic of a bidirectional source supply furnace for self-limiting CVD growth of PbX₂. (b and c) OM images of PbBr₂ and PbI₂, respectively. (d and e) Photo and OM images of PbBr₂. (f) Schematic of the MAPbBr₃ photodetector. (g) I–V curves of the device in the dark and under various light powers with 532 nm irradiation. (h) Responsivity of the MAPbBr₃ photodetector vs. irradiation wavelength; inset: SEM image of the device. (i) Rise/decay time of photocurrent under 532 nm excitation. (j) Responsivity of the perovskite devices in this work. (k) Comparison of rise/decay time and responsivity with recently reported perovskite photodetectors. Reproduced with permission.⁵⁷ Copyright 2024 Wiley-VCH GmbH.

Despite remarkable progress in 3D Pb-perovskite photovoltaics, fundamental limitations persist in achieving operational stability under prolonged illumination and thermal stress—challenges rooted in intrinsic ion migration across halide vacancies and compromised light extraction efficiency in thick active layers. These shortcomings have spurred dimensional engineering strategies, where 2D perovskite architectures leverage quantum-confinement effects and organic barrier layers to concurrently suppress ion diffusion while enhancing photon management. Recent advances in 2D metal halide perovskite optoelectronics reveal critical structure–property relationships, as schematized in Fig. 13a.⁵⁸ While conventional 150 nm films achieve complete light absorption for efficient photoconversion, their response speed is limited by extended carrier transit paths. Ultrathin architectures circumvent this by shortening transport distances, with nanocavity engineering further enhancing absorption in sub-100 nm films via destructive interference effects while preserving the ultrafast response. Material breakthroughs focus on Ruddlesden–Popper (RP) phase perovskites: Fig. 13b illustrates the atomic structure of PEA₂PbI₄, featuring alternating inorganic PbI₆-octahedra layers and organic spacers that enhance stability without sacrificing quantum confinement. Fig. 13c highlights phase-pure n = 1 perovskite synthesis via advanced solution processing, resolving historical challenges in crystallinity control and defect suppression. Structural analysis across multiple scales validates the material quality. Fig. 13d shows 10 nm-thick polycrystalline films with ultralow roughness and micron-scale coherence via AFM, critical for minimizing recombination. SEM confirms the layered morphology for device integration, as shown in Fig. 13e. XRD in Fig. 13f reveals periodic stacking via (002ℓ) Bragg reflections (1.6 nm spacing) and high-order peaks, confirming exceptional crystallographic order in the six-layer 2D system. They developed a vertical perovskite photodetector using PEA₂PbI₄, featuring an optimized ITO/PEA₂PbI₄/SnO₂/Ag architecture with favorable energy band alignment. It achieves an LDR of ∼80 dB across three orders of light intensity, as shown in Fig. 13g. The ultrathin architecture (Fig. 13h and i) enables ultrafast response characteristics with rise/fall times of 160 ns/128 ns under self-powered operation, representing a 500× acceleration over conventional 150 nm-thick perovskite devices (80 μs/70 μs) by minimizing carrier transit paths and recombination losses. Furthermore, the detector achieves a −3 dB bandwidth of ∼0.8 MHz at 405 nm (Fig. 13j), confirming its suitability for high-frequency optical signal detection, with performance limitations primarily dictated by RC constants and carrier transit dynamics. This work highlights the synergistic benefits of 2D perovskite light absorption and nanoscale thickness optimization in perovskite photodetectors for high-speed, broadband applications.

Fig. 13 (a) Schematic of light–matter interaction for (I) thick film, (II) ultrathin film, and (III) ultrathin film with an optical cavity. (b) Precursor solution of 2D perovskite PEA₂PbI₄ and its molecular structure. (c) Complete fabrication flow of perovskite thin film. (d) AFM topographic image and line profile of perovskite film. (e) High-magnification SEM image of perovskite film, highlighting well-defined 2D layers. (f) X-ray diffraction patterns of the 2D perovskite. (g) Linear dynamic response of the PD vs. incident light power. (h) ON–OFF switching behavior of a 150 nm thick perovskite PD. (i) ON–OFF switching behavior of a 10 nm thick perovskite PD with a cavity structure. (j) Frequency response of the cavity-structured perovskite PD measured at 0 V bias. Reproduced with permission.⁵⁸ Copyright 2025 Elsevier B.V.

While lead-based perovskites exhibit exceptional optoelectronic performance through high carrier mobility, tunable bandgaps, and efficient light conversion capabilities, their practical application faces fundamental limitations due to inherent toxicity and environmental persistence. Tin-based perovskites have emerged as promising Pb-free alternatives, retaining analogous optoelectronic advantages—including narrow bandgap for near-infrared spectral coverage, high charge carrier mobility, and suppressed ion migration kinetics—while effectively addressing critical ecological concerns. However, conventional Sn-based polycrystalline films suffer from oxidation-prone Sn²⁺ defects and grain boundary recombination, limiting device metrics. Ran et al.⁵⁹ pioneered a breakthrough by engineering phase-pure FASnI₃ single-crystal films via a confined epitaxial growth strategy. Their photodetectors exhibited an ultralow dark current (10⁻¹¹ A), a record detectivity of 3.2 × 10¹³ Jones, and ambient stability surpassing 1000 hours, outperforming their MA/FA-PbBr₃ counterparts in both responsivity (1.8 × 10³ A W⁻¹) and response speed (180 ns). This advancement underscores the viability of Sn-based single-crystal architectures to bridge the performance gap with Pb-based systems while eliminating toxicity concerns, positioning them as frontrunners for next-generation eco-friendly optoelectronics.

Beyond Sn perovskite photodetectors, Chu et al.⁶⁰ developed spectrally tunable photodetectors based on narrow-bandgap Pb–Sn alloyed perovskite single crystals with vertical bandgap gradients through compositional engineering, as shown in Fig. 14a. Fig. 14b demonstrates reciprocal Pb/Sn depth profiles via TOF-SIMS, where Sn signals decline sharply within the surface-proximal 100 nm while Pb increases, with gradient steepness controlled by ambient O₂ levels. The corresponding 3D Sn maps in Fig. 14c corroborate oxygen-enhanced surface Sn accumulation. Despite these metal gradients, uniform Cs/FA distributions in Fig. 14d and GIXRD-derived lattice expansion confirm structural coherence with Sn-rich surfaces. XPS analysis in Fig. 14e reveals progressive Sn⁴⁺ dominance at elevated O₂ levels, aligning spatially with surface Sn enrichment and bulk-to-surface oxidation gradients. Thermodynamic modeling in Fig. 14f establishes the critical role of O₂-mediated pathways: while direct Pb–Sn alloying remains energetically unfavorable (ΔH_f > 0), oxygen incorporation at iodide vacancies reduces substitution enthalpy, enabling Sn²⁺ → Pb²⁺ replacement. Fig. 14g illustrates this vacancy-driven mechanism, wherein O₂ occupancy initiates redox-coupled Sn oxidation and stabilizes Pb displacement, collectively enabling vertically graded bandgaps. The compositional gradient in Pb–Sn alloy systems enables enhanced charge carrier mobility and establishes a built-in electric field, facilitating exceptional performance in perovskite photodetectors with a measured −3 dB cutoff frequency of 46.4 kHz and a remarkable linear dynamic range (LDR) reaching 177 dB. The tin-enriched surface layer further demonstrates passivation effects by suppressing the formation of under-coordinated degradation sites, thereby achieving unprecedented operating stability exceeding one year. Notably, these devices demonstrate comparable color reproduction capabilities to commercial silicon photodetectors with integrated charge reset (ICR) technology when operating under infrared interference conditions. The demonstrated superior gray-level resolution positions this perovskite-based technology as a promising candidate for advanced day–night vision systems requiring seamless spectral transition capabilities.

Fig. 14 (a) Schematics showing the Pb−Sn alloyed in homogeneous and gradient structures. (b) Enlarged TOF-SIMS depth profiling of Sn and Pb ions in the upper surface region of various Pb_0.7Sn_0.3 single crystals. (c) ToF-SIMS 3D tomography showing Sn ion distribution in various Pb_0.7Sn_0.3 single crystals. (d) ToF-SIMS 3D tomography showing Pb, FA, and Cs ion distribution in the same crystals. (e) XPS of Sn 3d core peaks on the top surface of Pb_0.7Sn_0.3 single crystals prepared under different atmospheres. (f) Ab initio energy diagram of Pb–Sn alloying channels (without/with O₂ incorporation). (g) Schematic of Sn enrichment at the top surface during oxygen diffusion into iodine vacancies. Reproduced with permission.⁶⁰ Copyright 2024 Springer Nature.

Compositional engineering in perovskite photodetectors enables targeted optimization of optoelectronic performance through the synergistic design of lattice components and structural dimensionality. Strategic selection of A-site cations enhances lattice stability while suppressing ion migration. Two-dimensional perovskite architectures leverage quantum confinement effects and van der Waals-interlayered organic spacers to suppress non-radiative recombination while enhancing charge extraction kinetics. Concurrently, B-site alloying synergizes with X-site halide modulation to achieve broadband spectral tunability and mitigate lead-related environmental toxicity. The compositional gradient in Pb–Sn alloy systems significantly improves carrier mobility and spectral response uniformity. These multiscale design principles not only significantly enhance the high-speed response characteristics and spectral selectivity control capabilities of perovskite photodetectors but also establish a novel paradigm for environmentally friendly device architecture. This comprehensive strategy paves the way for developing next-generation photodetection technologies that integrate high operational stability with ecological compatibility, offering a systematic solution for sustainable optoelectronic innovation.

5.2. Dimensional engineering for perovskite PDs

The photovoltaic properties of perovskites are not only dependent on their components, but are also closely related to their dimensionality. Quantum size effects caused by dimensional constraints influence the electronic energy band structure and optoelectronic properties of perovskite materials. Nanostructured perovskites provide numerous additional advantages over polycrystalline thin films.¹²⁷ Currently, low-dimensional perovskite materials have been developed with different nanostructures for various optoelectronic devices, including 0D QDs, NCs, and NPs, 1D NWs, nanoribbons, and NRs, 2D NSs and nanoplates, while distinct nanostructure designs profoundly affect device performance. Significantly, the dimensions here are divided by the morphological form of the material, which is a nano-scale material with quantum confinement in at least one direction.^128–130 This section consolidates insights from studies on morphological dimension designs, highlighting its influence on the optoelectronic properties of perovskite materials and performance metrics of photodetectors.

5.2.1. PDs based on 0D perovskites. Perovskite quantum dots (QDs) exhibit excellent photovoltaic properties because they not only retain the intrinsic advantages of perovskite material, but also exhibit good light absorption due to the quantum confinement effect.^131,132 However, perovskite QDs are susceptible to defect formation because of their low defect formation energy, and these defects are also a negative factor affecting the dark current and stability of photodetectors. At the same time, the energy level mismatch between perovskite and ETL affects the stability and D* of the PDs.^133–137 Sun et al.⁴² developed CsPbBr₂I QDs (CQDs) with lattice stability and enhanced light absorption by the surface modulation of potassium trifluoroacetate (KTFA). The defects and vacancies in CQDs are effectively passivated because of the formation of Pb–O bonds, which inhibits the nonradiative complexation of photogenerated charges. Furthermore, the energy level mismatch of PD is mitigated due to the improvement in the figure of merit and valence band, which improves the hole transport capability. PDs exhibit a dark current as low as 2.79 × 10⁻¹¹ A, and the device shows an R of 0.375 A W⁻¹, a D* of 1.12 × 10¹³ Jones, and an on/off ratio of up to 10⁴. The stable cyclic response curve exhibits the repeatability and reliability of the 5% KTFA CQDs PDs. These stimulating results demonstrate that surface modulation by KTFA has a promising application in flexible self-powered perovskite photovoltaic cells. Song et al. used FAPbI₃ QDs to backfill the interconnected MAPbI₃ network with an ordered pore array.¹³⁸ The resultant PC structure induces enhanced light harvesting over the visible light spectral region, leading to an improved photon-to-current conversion efficiency, as shown in Fig. 15. The UV-vis and PL spectrum result is shown in Fig. 15a and b. As shown in Fig. 15d, when the MAPbI₃/FAPbI₃ perovskite heterodomain forms, the EF of both perovskites is aligned, which leads to 0.29 eV CBM offset and 0.25 eV VBM offset. This energy level diagram implies that the photoinduced holes (minority carriers) will be injected from the FAPbI₃ QDs to the porous MAPbI₃. Fig. 15e illustrates the charge carrier transport mechanism. The perovskite heterodomain configuration endows the active layer with massive interfaces, largely increasing the charge-carrier separation efficiency and reducing the charge carrier recombination probability. Moreover, the ordered local nanophase separation of perovskites is expected to inhibit the lateral transport of charge carriers in the FAPbI₃ QD film, facilitating the charge carrier collecting at electrodes. By imposing the PC structure on the perovskite layer, a well-performed self-powered photodetector is achieved, which demonstrates a high photoresponsivity of 1.37 A W⁻¹ and an impressive specific detectivity of 3.71 × 10¹⁴ Jones at 600 nm. In addition, the device exhibits fast response times of 6.6/7.9 μs as well as excellent ambient stability. This work provides an innovative approach to the structural design of perovskite heterojunction-based photodetectors.

Fig. 15 (a) UV-vis absorption. (b) PL and (c) TRPL spectra of the QD film, porous MAPbI₃, and QDs-PC samples. (d) Energy level diagram of the FAPbI₃ QDs and porous MAPbI₃ films. (e) Schematic diagram of charge carrier transport in the QDs-PC film. (f) Time–wavelength-dependent TAS 2D map of the QDs-PC sample and (g) selected temporal photon bleaching spectra. (h) Fraction of the extracted GSB decay of the MAPbI₃ (≈ 760 nm) and FAPbI₃ (≈ 780 nm) components in the QDs-PC film as a function of time. (i) The GSB delay spectra for the QD film, porous MAPbI₃ sample, and individual MAPbI₃ and FAPbI₃ components of the QDs-PC sample. Reproduced with permission.¹³⁸ Copyright 2024 Wiley-VCH GmbH.

The remarkable photoelectric properties of perovskite NCs have attracted as much interest in them as PDs. These detectors have a tunable band gap, excellent carrier migration behaviour, and effective light harvesting. Although NCs-based optoelectronic devices like CsPbX₃ have exhibited exciting progress, the performance of the device, especially stability, is still far from adequate for the application requirements. Therefore, it is important to resolve the environmental stability of NCs, while achieving efficient charge transfer to ensure high device performance. Gong et al.¹³⁹ developed an all-inorganic CsPbCl₃ nanocrystal perovskite photodetector and obtained superior environmental stability by using 3-mercaptopropionic acid (MPA) to passivate the crystal surface, then printed these NCs into the channel of graphene field effect transistors (GFETs) and constructed the CsPbCl₃ NCs/GFET heterojunction photodetector on a flexible substrate of polyethylene terephthalate. Through theoretical simulations, the passivation mechanism of the MPA ligand and the role of the ligand on charge transfer at the NC/GFET interface were elucidated. The relaxed structure of the MPA ligands on the CsPbCl₃ NC surfaces, and one/four MPA ligands connected on the NCs and graphene, were also revealed. Therefore, the MPA ligands are attached toward the ends, creating relative conformational stability. This stabilized structure on the one hand prevents the degradation of CsPbCl₃ NCs, and on the other hand reduces charge trapping from intrinsic surface defects. The device had an ultrahigh R of 10⁶ A W⁻¹ under visible-blind UV, a high D* of 2 × 10¹³ Jones and only a 10% decrease in photoresponse after 2400 h. In summary, the issues of environmental stability of CsPbCl₃ NCs can be resolved by an MPA ligand passivation effect. It has also been found that CsPbCl₃ NCs’ outstanding charge transformation is associated with the passivation of perovskite surface defects by MPA, and these play an important role in the responsivity of photodetectors.

In recent years, lead-free perovskites have been developed and applied by numerous scholars due to the increasing environmental awareness. Lead-free perovskite QDs have also attracted a research boom due to their excellent electrical and optical properties. However, the performance of optoelectronic devices based on such lead-free perovskite is still much lower than their lead-based counterparts. Ma et al.¹⁴⁰ reported a lead-free photodetector of PET/Ag NP/Al₂O₃/CsSnBr₃ QD/Au with an enhanced response ranging from 300 nm to 630 nm. The plasmonic near-field enhancement and surface energy burst are balanced by accurately controlling the thickness of the Al₂O₃ layer between the QDs and the Ag NPs. When the Al₂O₃ has a 5 nm thickness the photodetector experiences the highest photocurrent, which is 6.5 times the initial value, with an R of 62.3 mA W⁻¹ and D* of 4.27 × 10¹¹ Jones. Moreover, its photocurrent displays excellent stability after 100 cycles of bending.

5.2.2. PDs based on 1D perovskites. Since perovskite NRs have remarkable photoelectric properties, they are being studied in great detail, especially for PD applications. These NRs are used in phototransistors, photodiodes, and photoconductors, among other perovskite PDs.¹⁴¹ Using perovskite NRs with organic semiconductors has demonstrated encouraging results, particularly in creating high-efficiency phototransistors that exhibit exceptional stability and photosensitivity. Lee et al.¹⁴² reported a simple synthesis method of perovskite nanowires by effective template-free self-assembly. The difference in particle surface interaction energies drives 1D self-assembly of perovskite grains. The perovskite granular wire (PGW) has a well-defined granular morphology. It has great potential for high D* photodetectors due to their unique, morphologically derived intrinsic band-edge modulation that inhibits the dark current. The striking D* is up to 3.17 × 10¹⁵ Jones at a bias of −8 V, which is the highest value reported to date in perovskite materials. In the dark, the device exhibits good insulation with dark currents as low as 1 pA. The calculated LDR is 89 dB, which is comparable to conventional perovskite nanomaterials. The suppression of the dark current is associated with energy band bending on the perovskite surface. Here, researchers used Kelvin probe force microscopy (KPFM) to investigate the energy band bending properties and photoelectric behavior of grain boundaries and grains in PGWs. The “self-assembled nanoparticle engineering” strategy provides a viable approach for the potential development of high-performance perovskite photodetectors.

The development of high-performance PDs appears to be greatly promising for perovskite NWs. The research has focused on using single-crystalline, solution-processable perovskite NWs to create inexpensive PDs with high detectivity. Furthermore, advancements in PDs’ sensitivity have been made by employing conductive materials, self-assembled quantum wells, and strongly interacting layered metal–halide perovskites. The solution method of preparing nanowires is often considered to be a promising preparation method with low cost and easy scale-up fabrication. However, it is difficult to control the coverage, defects, aspect ratio and alignment direction of nanowires by this method.¹⁴³ In order to realize a simple but effective strategy to prepare high-quality perovskite nanowire arrays, Ma et al.¹⁴⁴ designed a template-assisted antisolvent crystallization (TAAC) method and successfully prepared nanowire arrays with low crystalline defects, well-ordered arrangements, and designable shapes. The acetonitrile vapor can slow down the evaporation of DMSO and inhibit the precipitation of perovskite crystals. The NWs can achieve hundreds of micrometers in length without any nodes or cracks, and have continuous and regular morphology, smooth surfaces, sharp edges, and uniform spacing. Under the laser with an optical wavelength of 532 nm, the R and D* of the corresponding PDs are 1.5 A W⁻¹ and 1.21 × 10¹² Jones, respectively, and the on/off ratio over 10³. The photocurrent remains at 80% of the initial value. This method provides an efficient and controllable way to fabricate high-ordered, high-quality NW arrays. Duan et al. report a wafer-scale controllable growth method for perovskite periodic heterojunction nanowire superlattices by an improved chemical vapor deposition (CVD) approach, as shown in Fig. 16a–c.¹⁴⁵ This method is an effective synthesis approach that could overcome the poor controllability of the perovskite solid sources under high temperatures and produce a reasonable strategy to fabricate periodic perovskite nanowire superlattice arrays. Compared with single-component CsPbCl₃ nanowire photodetectors, the nanowire superlattice photodetector shows an expected superior performance, including a high on/off ratio of 10⁴, high responsivity of 49 A W⁻¹, and high specific detectivity of 1.51 × 10¹³ Jones. These results suggest that the periodic perovskite nanowire superlattices may have potential applications in high-integrated and multifunctional optoelectronic devices in the future. Zhai et al. used BMIMBF₄ as an additive in the fabrication of MAPbI₃ nanowires, resulting in MAPbI₃ nanowire PDs with adequate long-term stability and performance, as shown in Fig. 16d–f.¹⁴⁶ Specifically, the unencapsulated MAPbI₃ nanowire PD shows no performance degradation after being exposed to open air for more than 5000 h, establishing it as the most stable perovskite nanowire PD reported to date. Besides, the MAPbI₃ nanowire PD exhibits a remarkable performance with a detectivity, LDR, and NEP of 2.06 × 10¹³ Jones, 160 dB, and 1.38 × 10⁻¹⁵ W Hz^−1/2, respectively. Zhao et al. demonstrate a type of ultrasensitive photodetector based on single-crystalline MAPbBr₃/MAPbBr_3−xI_x p–n junction nanowire (NW) arrays, as shown in Fig. 16g–i.¹⁴⁷ The perovskite p–n junction NW arrays with seamless interfaces were fabricated via a selective-area anion exchange approach. With high phase purity and excellent crystallinity, the NW arrays ensure efficient carrier transport. A considerable responsivity of 2.65 × 10² A W⁻¹ and a high I_on/I_off ratio of 2.4 × 10⁵ under 532 nm illumination have been achieved.

Fig. 16 (a) Schematic diagram of a photodetector based on perovskite nanowire superlattices. (b) Elemental profile line scan of the nanowire. (c) Response time of the nanowire photodetector under 405 nm laser illumination. Reproduced with permission.¹⁴⁵ Copyright 2024 American Chemical Society. (d) Schematic diagram of the Au/MAPbI₃ NW/Au structure device with BMIMBF₄ (0.6 mmol). (e) I–t curves with different light intensities. (f) Response time recorded at 14.5 mW cm⁻² of light intensity. Reproduced with permission.¹⁴⁶ Copyright 2022 John Wiley and Sons. (g) MAPbBr₃/MAPbBr_3−xI_x p–n junction device diagram. (h) MAPbBr₃/MAPbBr_3−xI_x p–n junction's energy band alignment under thermal equilibrium. (i) MAPbBr₃/MAPbBr_3−xI_x p–n junction device's dark I–V curve at a 5 V bias. Reproduced with permission.¹⁴⁷ Copyright 2022 Wiley-VCH GmbH.

Although the stability of 1D perovskite-based photodetectors is significantly improved compared with that of perovskite thin films, it is crucial to develop a method with a short preparation time and low cost while improving the stability of the devices for practical applications. Li et al.¹⁴³ proposed an in situ encapsulation method on the basis of edge adsorption to significantly improve the stability of MAPbBr₃ single-crystal microwire arrays (SCMWAs) and further enhance the service life of photodetectors. During the preparation, SCMWAs were encapsulated in situ by a hydrophobic trichloro (1H,1H,2H,2H-perfluorooctyl) silane (FOTS) molecular protective layer on the surface of the PDMS microstructures, which isolated it from moisture. The high crystallization quality of MAPbBr₃ SCMWAs can be demonstrated by the performance of SCMWA-based devices. The photoresponse behavior of the device was measured under irradiation with light sources with different light intensities. The device has a calculated LDR of 124 dB, which is comparable to conventional silicon-based photodetectors. The MAPbBr₃-SCMWA-based photodetector was confirmed to have good stability when exposed to air and humidity. After exposure to air for more than 340 d, the device maintained 96% of the initial photocurrent value. The device remained at 95% of its original photocurrent value even after 10 d of exposure to an environment of 60% relative humidity. In this work, a lower grain boundary and defect densities, as well as a hydrophobic molecular protective layer phase, combine to improve the stability of MAPbBr₃ SCMWAs.

5.2.3 PDs based on 2D perovskites. 2D perovskite photodetectors leverage engineered layered architectures to achieve breakthrough performance: crumpled topographies or vertically thinned configurations enable high responsivity with nanosecond-scale response times, surpassing the classical speed limits of conventional devices. Coupled with low-temperature solution processing and wafer-scale compatibility, these systems reduce manufacturing costs. Jing et al.¹⁴⁸ reported a quasi-static solution synthesis, which can fabricate low-cost ultra-thin single-crystal two-dimensional CH₃NH₃PbBr₃ perovskite NSs. After 1000 bending tests, the photocurrent and on/off switching ratio of the device did not deteriorate significantly, and the R and D* remain stable. The results show that the thickness reduction of single-crystal perovskites effectively improves the flexibility and bending durability of flexible devices. The photodetector using an ultra-thin single-crystal film as the active layer achieves an ultra-high R of 5600 A W⁻¹, which is two orders of magnitude higher than previous polycrystalline films, as well as a fast time response with rise and fall times of 3.2 μs and 9.2 μs, respectively. The 3 dB bandwidth was 0.2 MHz. The results demonstrate the great potential of 2D single-crystal perovskite ultrathin films for the development of wearable and flexible optoelectronic devices. Wang et al. developed PDs to investigate the optoelectronic properties of FAPbBr₃ NSs.¹⁴⁹ The PD's device structure, which depends on a single FAPbBr₃ NS, is shown in Fig. 17a. The time-resolved photoresponses at V_ds = 3 V for 405 nm with 5.5 mW cm⁻² and 532 nm with 20 mW cm⁻² are shown in Fig. 17b. For the 405 and 532 nm cases at V_ds = 3 V, the PDs show high light current to dark current values (on/off ratio) of roughly 10⁴. The sensitivity values obtained with 405 and 532 nm lasers excited at V_ds = 3 V are displayed in Fig. 17c. The results indicate a high on/off ratio of 10⁴, an EQE greater than 3000%, an ultrahigh responsivity of 10³³ A W⁻¹, and a fast response time of roughly 25 ms. Mei et al.¹⁵⁰ demonstrated a monocrystalline MAPbBr₃ nanoplate photodetector which achieves an efficient UV-Vis-SWIR broadband optical response and fast response. By using the low temperature vapor diffusion method, controlling the size and thickness of single-crystal nanoplates at the nanoscale does not require an additional annealing process. The photodetector based on nanoplates exhibits a high external EQE and D* of 1200% and 5.37 × 10¹² Jones, and fast rise/fall time of 80/110 µs. The excellent performance of the devices is closely related to the reduction of grain boundaries and the increase in specific surface area of the single-crystal nanoplate. Zhong et al.¹⁵¹ investigate the solution-processed synthesis of perovskite CsPb₂Br₅ nanosheets by using water and ethanol as solvents, shown in Fig. 17d–f. The results show that the aqueous environment ensures the phase formation of CsPb₂Br₅ and that the supersaturated solution in ethanol boosts the nucleation of the nanosheets. The substrate temperature is the key factor for the evolution of morphology and the variation of the thickness of CsPb₂Br₅ nanosheets. The spatial and time-resolved fluorescence spectra indicate the heterogeneity of the defect density and the recombination process in different nanosheet regions. The photodetector based on the prepared CsPb₂Br₅ nanosheet displays an excellent switching current ratio (9 × 10²), a short rise and decay time (43 and 83 ms, Fig. 17f), and good stability (75% of the initial current after 90 days in air). In addition, the mechanical stability and flexibility of the photodetector on the flexible substrate are investigated for 500 bending cycles. Novel 2D all-inorganic perovskite CsPbCl_xBr_3−x NSs doped with rare earth ions were synthesized, as reported by Song et al.¹⁵² As shown in the inset of Fig. 17g–i, the planar device structure based on the lateral assembly of 2D perovskite NSs was selected to create PDs. This choice was taken in light of planar structures’ superior electrical qualities. Compared with the vertically assembled samples, the laterally assembled Yb³⁺ ion-doped NS film exhibited faster carrier mobility and less defect density. The PDs based on the laterally assembled Yb³⁺-doped perovskite NS film showed excellent performance, including fast responding time (μs) and high detectivity (>10¹² Jones). More importantly, PD based on Yb³⁺-doped NS showed the ability to detect and distinguish the dual-band light combining UV and NIR light.

Fig. 17 (a) Diagram illustrating an FAPbBr₃ PD. (b) PD's time-resolved photoresponse when excited by 405 and 532 nm lasers at V_ds = 3 V. (c) Responsivity values computed at V_ds = 3 V while 405 and 532 nm lasers are excited. Reproduced with permission.¹⁴⁹ Copyright 2024 American Chemical Society. (d) SEM images of the CsPb₂Br₅ nanosheets. (e) I–V curves of the photodetector under different powers of incident light. (f) Time-dependent photocurrent measurement under different voltages. Reproduced with permission.¹⁵¹ Copyright 2020 American Chemical Society. (g) Diagram illustrating the CsPbCl₃ PD. (h) Photocurrent of Yb³⁺-doped and undoped NSs devices under various UV light wavelengths. (i) Potential mechanism of Yb³⁺-doped CsPb(Cl/Br)₃. Reproduced with permission.¹⁵² Copyright 2023 Elsevier Ltd.

Extending beyond the morphological dimensionality advances detailed above, we perform systematic quantification of photodetector performance metrics across all perovskite architectural classes, as shown in Table 2. Building on our systematic analysis of the perovskite morphological dimension and its correlative material/device properties, we consolidate the merits and constraints of each structural configuration with respect to photodetector performance benchmarks. Each morphological architecture exhibits distinct performance tradeoffs. 0D perovskites demonstrate broad-spectrum photodetection capabilities covering UV to visible light wavelengths, but have the worst environmental stability. 1D perovskite exhibits enhanced charge carrier mobility while suppressing recombination rates, resulting in a better response time. But the manufacturing consistency and volume scaling are difficult, affecting commercial viability. 2D perovskites confer enhanced environmental stability and offer scalable synthesis advantages via solution-processable fabrication protocols. However, this architectural configuration inherently constrains the spectral response range, manifesting as a narrowed light-harvesting bandwidth. A comprehensive performance summary across dimensional architectures is schematically depicted in Fig. 18. Furthermore, a holistic assessment encompassing operational stability, manufacturing feasibility, and cost-effectiveness provides critical implementation guidelines. Leveraging these, researchers can engineer nanoscale perovskites with specific dimensions designed for desired optical and electrical properties by carefully choosing the morphology dimension. This degree of control is essential to optimize these materials for various uses.

Fig. 18 Morphological dimension design regulates the properties of perovskite materials and the performance of photodetectors.

Table 2 Performance of different dimensional perovskite-based photodetectors

Active materials	Driving voltage (V)	R (light source, intensity)	D (light source, intensity)	LDR (dB)	Response time [rise time (τr)/fall time (τf)]	Ref.
0D
MAPbI3 NPs	26	4.9 mA W^−1 (blue light)			50/120 μs	61
FAPbBr3 QDs/graphene	2 (drain)	1.15 × 10^5 A W^−1 (520 nm, 3 μW)			0.058/0.060 s	62
APbX3 (A = MA, FA, Cs; X = Br, Cl, I) NCs	2	0.15 × 10^−3 A W^−1 (365 nm, 60 mW cm^−2)				63
CsPbI3 NCs	−0.5	0.035 A W^−1 (640 nm)	1.8 × 10^12 Jones (640 nm)	85.6	100/100 μs	64
CsPbI3 QDs	1.0	100 mA W^−1	5 × 10^13 Jones (450 nm)			14
CsPbI3 QDs + up-conversion materials	5	1.5 A W^−1			<5 ms/<5 ms	65
CsPbI3 QDs/polymer DPP-DTT	−30 (drain)/−30 or 0 (gate)	110 A W^−1 (405 nm, 0.008 mW cm^−2)	2.9 × 10^13 Jones (405 nm, 0.008 mW cm^−2)		3.2/3.3 s	66
CsPbI3−xBrx QDs/monolayer MoS2	1 (drain)/60 (gate)	7.7 × 10^4 A W^−1 (532 nm, ∼nW)	5.6 × 10^11 Jones (532 nm, ∼nW)		0.59/0.32 s	67
CsPbBr3 QDs	−0.7	3 A W^−1 (365 nm, 4.3 mW cm^−2)	1 × 10^14 Jones (365 nm, 4.3 mW cm^−2)	90	<0.002/<0.002 s	68
CsPbBr3 QDs		1.9 A W^−1	1.3 × 10^12 Jones		17.5/10.3 ms	69
CsPbBr3 QDs/mesoporous TiO2	4	3.5 A W^−1			∼s	70
CsPbBr3 QDs/mesoporous TiO2	2	24.5 A W^−1	8.9 × 10^13 Jones (405 nm, 0.1 mW cm^−2)		4.7/2.3 s	71
CsPbBr3 NCs/multilayer graphene	0.2	2 × 10^4 A W^−1 (400 nm, 0.06 nW)	8.6 × 10^10 Jones (400 nm, 0.06 nW)		3.1/24.2 s	72
CsPbBr3 NCs + Au NCs	2	10.04 mA W^−1 (520 nm)	4.56 × 10^8 Jones		0.2/1.3 ms	73
CsPbBr3 QDs + PbS QDs	2 (drain)/0 (gate)	4.5 × 10^5 A W^−1 (400 nm)	1.26 × 10^13 Jones (400 nm)		6.5/7.5 ms	74
CsPbBr3−xIx NCs/graphene	1 (drain)/−60 (gate)	8.2 × 10^8 A W^−1 (405 nm, 0.07 μW cm^−2)	2.4 × 10^16 Jones (405 nm, 0.07 μW cm^−2)		0.81/3.65 s	75
CsPbBr3 QDs/polymer DNTT	−10 (drain)/−40	1.7 × 10^4 A W^−1	2.0 × 10^14 Jones		∼s	76
CsPbBr3 QDs/PC71BM	2 (drain)/−1 (gate)	1.72 A W^−1 (405 nm, 234 mW cm^−2)	1.76 × 10^7 Jones (405 nm, 234 mW cm^−2)		0.09/0.1 ms	77
CsPbCl3 NCs	5	1.89 A W^−1 (365 nm, ∼10−2 mW cm^−2)			0.041/0.043 s	78
CsPbCl3 NCs	1	>10^6 A W^−1 (400 nm, 6.72 μW cm^−2)	>2 × 10^13 Jones (400 nm, 6.72 μW cm^−2)		0.3/0.35 s	79
CsSnBr3 QDs and Ag nanoparticle	3	62.3 mA W^−1 (410 nm, 15 mW cm^−2)	4.27 × 10^11 Jones (410 nm, 15 mW cm^−2)		50/51 ms	80
MAPbI3 NCs	4	12.2 mA W^−1 (405 nm, 8.41 mW cm^−2)	2.67 × 10^11 Jones (405 nm, 8.41 mW cm^−2)		18/25 ms	81
CsPbBr2I QDs	0	0.375 A W^−1 (532 nm)	1.12 × 10^13 Jones (532 nm)	91.1	3.8/4.5 ms	82
1D
MAPbI3 nanowires	5	460 A W^−1 (460 nm, 560 μW cm^−2)	2.6 × 10^13 Jones (460 nm, 60 μW cm^−2)		180/330 μs	83
MAPbI3 nanowires	5	15 mA W^−1 (405 nm)	3.5 × 10^11 Jones (405 nm)		12/22 ms	84
MAPbI3 nanowires	1	4.95 A W^−1 (μW cm^−2)	2 × 10^13 Jones (μW cm^−2)	70	<0.1 ms/<0.1 ms	85
MAPbI3 nanowires/C8BTBT	3	8.1 A W^−1 (532 nm, 0.0075 mW cm^−2)	2.17 × 10^12 Jones (532 nm, 0.0075 mW cm^−2)		7.1/6.5 ms	86
MAPbI3 nanopillars	50	1 A W^−1 (1 μW)	5 × 10^9 Jones (1 μW)		<100 ms/<100 ms	87
SCN-doped MAPbI3 nanowire network	2	0.23 A W^−1 (532 nm)	7.1 × 10^11 Jones (490 nm)		53.2/50.2 μs	88
MAPbI3 microwires	10	1.2 A W^−1 (630 nm, 0.1 mW cm^−2)	2.39 × 10^12 Jones (630 nm, 0.1 mW cm^−2)		<10 ms/<10 ms	89
MAPbI3−x(SCN)x nanowires	10	0.62 A W^−1 (white light)	7.3 × 10^12 Jones (white light)		227.2/215.4 μs	90
MAPbI3 nanoribbon arrays	2	38.9 mA W^−1 (38.5 μW cm^−2)	8.21 × 10^11 Jones (300 nm)		27.2/26.2 ms	91
MAPbBr3 milliwires	2	525 mA W^−1 (570 nm)			0.407/0.895 s	92
MAPbI3 microwire arrays	−5	13.57 A W^−1 (420 nm)	5.25 × 10^12 Jones	114	80/240 μs	93
1D MAPbX3 single crystal microwire arrays (X = Cl, Br, I)	5	3.16 × 10^3 A W^−1 (0.0177 nW)				94
MAPb(I1−xBrx)3 (x = 0, 0.1, 0.2, 0.3, 0.4) nanowire arrays	5	12 500 A W^−1	1.73 × 10^11 Jones	150	0.34/0.42 μs	95
MASnI3 nanowire arrays	5	0.47 A W^−1 (1.1 mW cm^−2)	8.8 × 10^10 Jones (1.1 mW cm^−2)		1500/400 ms	96
CsPbI3 nanowires	1	0.745 A W^−1 (530 nm, 0.282 mW cm^−2)	3.46 × 10^10 Jones (530 nm, 0.282 mW cm^−2)		∼s	97
CsPbI3 nanowires	1	6.7 mA W^−1 (1.5 mW cm^−2)	1.57 × 10^8 Jones (1.5 mW cm^−2)		0.292/0.234 s	98
CsPbI3 nanorods	2	2.92 × 10^3 A W^−1 (405 nm)	5.17 × 10^13 Jones (405 nm)		0.05 ms/0.15 ms	99
CsPbI3 nanorods/C8BTBT	−30 (drain)/−60 (gate)	4300 A W^−1 (white light, ∼10^−1 mW cm^−2)			∼s	100
Csx(CH3NH3)1−xPbI3 nanowires	5	23 A W^−1	2.5 × 10^11 Jones		10/20 ms	101
CsPb0.922Sn0.078I3 nanobelts	2	1.18 × 10^3 A W^−1 (405 nm)	6.43 × 10^13 Jones (405 nm)		240/271 ms	102
CsPbCl3 microwires		14.3 mA W^−1 (405 nm, 0.7 mW)			3.212/2.511 ms	103
CsPbBr3 nanowires	0	0.3 A W^−1 (10^−2∼10^−4 mW cm^−2)	1 × 10^13 Jones (10^−2∼10^−4 mW cm^−2)	135	0.4/0.43 ms	104
CsPbBr3 nanowires	3	4400 A W^−1 (405 nm, 0.2 mW cm^−2)			252/300 μs	105
CsPbBr3 nanowires	5	7.26 mA W^−1 (463 nm, 60 μW cm^−2)	1.7 × 10^11 (463 nm, 60 μW cm^−2)		10/22 ms	106
CsPbBr3 microwires	5	118 A W^−1 (520 nm)	8 × 10^12 Jones (520 nm)		38/36 ms	107
CsPbBr3 nanowires/InGaZnO	5	3.794 A W^−1 (365 nm, 2.93 mW cm^−2)			2/2 ms	108
CsSnI3 nanowires array	0.1	54 mA W^−1 (940 nm, 50 mW mm^−2)	3.85 × 10^5 Jones (940 nm, 50 mW mm^−2)		83.8/243.4 ms	109
MAPbBr3 NWs	−1	1.55 A W^−1 (532 nm, 0.1 μW)	1.21 × 10^12 Jones (532 nm, 0.1 μW)		110/220 ms	110
MAPbI3 granular wires	−8	2.75 A W^−1 (650 nm, 10 µW cm^−2)	3.17 × 10^15 Jones (650 nm, 10 µW cm^−2)	89		111
MAPbBr3 single-crystal microwire arrays	1	20 A W^−1 (365 nm)	4.1 × 10^11 Jones	95	1.6/6.4 ms	112
2D
MAPbI3 nanosheets	0.8	36 mA W^−1 (635 nm, 50.82 μW)			320/330 ms	113
MAPbI3 nanosheets	1	22 A W^−1 (405 nm, ∼pW)			<20 ms/<40 ms	114
CsPbBr3 nanosheets/PCBM	9/5	10.85 A W^−1 (442 nm)	3.06 × 10^13 Jones (525 nm)	73	44/390 μs	115
CsPbBr3 nanosheets	10	0.64 A W^−1 (517 nm)			19/25 μs	116
CsPbBr3 nanoplatelets	1.5	34 A W^−1 (442 nm, 0.2 mW cm^−2)	7.5 × 10^12 Jones (442 nm, 0.2 mW cm^−2)	28	0.6/0.9 ms	117
CsPb2Br5 nanoplatelets	6	340 μA W^−1			0.426/0.422 s	118
CsPbBr3 nanosheets/CuSCN	1	11 A W^−1 (365 nm, 4 mW cm^−2)	1.8 × 10^11 Jones (365 nm, 4 mW cm^−2)	55	2.65/4.00 s	119
CsPbBr3 nanosheets/ZnO nanowires	9	3.10 A W^−1 (380 nm)	5.57 × 10^12 Jones (380 nm)			120
CsPbBr3 nanoplatelets/MoS2	0.5	13.1 A W^−1 (442 nm, 1.4 mW cm^−2)			2.5/1.8 ms	121
CsPbBr3 microplatelets	5	1.33 A W^−1 (405 nm, 1 μW)	8.6 × 10^11 Jones (405 nm, 1 μW)		20.9/24.6 ms	122
CsPbBr3 microplates		110 mA W^−1 (532 nm, 10 mW cm^−2)	4.5 × 10^13 Jones (532 nm, 10 mW cm^−2)		120/180 ms	123
CsPb0.966Sn0.034Br3	−7	5 A W^−1	10^11 Jones		1163/144 μs	124
CsPbBr3 nanosheets/MoS2	10	4.4 A W^−1 (442 nm, 0.02 mW cm^−2)	2.5 × 10^10 Jones (442 nm, 0.02 mW cm^−2)		0.72/1.01 ms	125
CsPbBr3 nanosheets/carbon nanotubes	10	31.1 A W^−1		85	16/380 μs	126

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5.3. Large-scale perovskite PDs

The development of perovskite photodetectors has positioned large-area array integration for image sensors as a critical focus in optoelectronics research. Traditional perovskite photodetector arrays, often fabricated as continuous unpatterned thin films, exhibit substantial inter-pixel electrical crosstalk that undermines imaging accuracy. Recent innovations in scalable fabrication techniques—including photolithography-assisted patterning, screen printing, and inkjet printing—have emerged to mitigate these issues by enabling precise spatial control of pixel architectures. However, achieving reliable integration with high pixel density, uniformity, and manufacturing yield remains challenging, requiring further advancements in process engineering. Consequently, the development of large-scale perovskite photodetector arrays with uniform optoelectronic properties continues to be an urgent priority and a central research direction in this field.

Utilizing the inherent processing simplicity of traditional perovskite solution deposition, Wei et al.¹⁵³ developed large-area photodetector arrays based on quasi-2D PVKs/IGZO heterostructure films on flexible substrates. The IGZO top layer serves dual functions: forming a type-II heterojunction with perovskites for efficient charge separation while acting as a protective coating against environmental degradation, thereby ensuring remarkable operational stability. This architecture maintains scalable fabrication compatibility and fulfills critical requirements for practical imaging sensors, demonstrating excellent spatial uniformity and enhanced environmental/operational stability. As shown in Fig. 19a, the transfer characteristics under varying light intensities revealed a significant threshold voltage shift of 3.3 V at ultralow illumination (0.08 μW cm⁻²), indicative of hole-trapping-induced optical gating. The light-to-dark current ratio reached 3.3 × 10⁵ under 4.28 μW cm⁻² illumination. Fig. 19b demonstrates photoamplified output characteristics through carrier injection into the IGZO channel, while Fig. 19c shows gate-voltage-modulated responsivity peaking at 3.1 × 10⁵ A W⁻¹ near V_gs = 0 V. Supporting this mechanism, the power-law exponent α < 1 (minimum α = 0.56) in Fig. 19d systematically confirms optical gating dominance over conventional photoconduction. The detectivity performance in Fig. 19e highlights a critical trade-off: maximum responsivity at V_gs = 0 V contrasts with optimal detectivity at V_gs = −6 V due to dark current noise suppression. Broadband sensitivity extending beyond PVK's absorption edge, as evidenced by Fig. 19f, arises from trap-assisted photoconduction in near-infrared regions. The scalability evaluation in Fig. 19g achieved submillimeter spatial resolution for patterned illumination recognition (“H”), with Fig. 19h and i demonstrating <20% photocurrent degradation after one-month ambient storage. This stability enhancement stems from the IGZO encapsulation layer, confirming the system's viability for large-area imaging and dynamic light tracking applications.

Fig. 19 (a) Transfer characteristic curves under different P_light; inset showing the light-to-dark current ratio for different P_light. (b) Output characteristic curves under different P_light at V_gs = −6 V. (c) Responsivity related to V_gs and P_light extracted from (a). (d) I_phvs. incident power, inset showing extracted exponent α for different V_gs. (e) Noise analysis of IGZO-PVK phototransistors from a Fourier transform of dark current. (f) Transfer characteristic curves of lasers with different wavelengths. (g) Schematic of a flexible 2D PVK/IGZO photodetector array for multi-point light distribution detection. (h and i) Photocurrent mapping of a photodetector array with an H-shaped mask. Reproduced with permission.¹⁵³ Copyright 2019 WILEY-VCH GmbH.

Addressing the inherent limitations of conventional perovskite arrays, such as poor homogeneity and electrical crosstalk caused by continuous polycrystalline films, Yin et al.¹⁵⁴ developed patterned perovskite single-crystal arrays via a PDMS templating strategy, as shown in Fig. 20a. Their approach incorporated SAM-bridged interfaces and dimensional tuning of nanoarrays to simultaneously enhance optoelectronic performance and mechanical stability, enabling resilient wearable devices with preserved operational integrity under aggressive bending and ultrasonic stress. Under 850 nm illumination, the logarithmic I–V curves (Fig. 20b and c) revealed a striking superlinear photocurrent dependence on light intensity, deviating from the typical linear/sublinear trends caused by carrier recombination. This anomaly, quantified by a power-law exponent α = 5.25 in Fig. 20d, surpassed most reported perovskite devices. Researchers attributed this behavior to a dual recombination center (RC) model (Fig. 20f–h), where high-intensity light fills defect-induced gap states (RC2), suppressing recombination and boosting carrier lifetimes. The device exhibited a broad spectral response extending to 1050 nm (Fig. 20e) and achieved rapid response dynamics with a 206 ms rise time and 202 ms decay time (Fig. 20j), while maintaining reliable cyclic stability under periodic switching (Fig. 20i). Fig. 20k presents the results of evaluating detectivity by measuring the frequency-modulated noise current, where the noise current is dominated by 1/f noise in the low-frequency region and approaches the shot noise limit in the high-frequency region. Notably, the SAM-optimized detector delivered record-breaking metrics: a responsivity of 1.66 A W⁻¹ and detectivity of 6.19 × 10¹² Jones at 10 Hz (Fig. 24l)—37× higher than its SAM-free counterparts. Comparative benchmarks (Fig. 24m) confirmed its superiority in near-infrared detection among perovskite-based systems. Remarkably, the Cu(GABA)₂PbBr₄ device retained over 60% of its initial responsivity after 60 days in humid air (50% RH), outperforming conventional FAPbI₃ devices that rapidly degraded (Fig. 24n). By integrating a fast response, environmental robustness, and defect-engineered superlinearity, this work demonstrates the synergy of interface modification and carrier dynamics control in advancing perovskite optoelectronics toward practical applications.

Fig. 20 (a) Flexible photodetector structure schematic. (b) I–V curves of perovskite single crystal arrays under 850 nm light. (c) Device photocurrent and responsivity at 5 V bias. (d) Photocurrent under different irradiance values with a power-law fitting. (e) I–V curves of perovskite single crystal arrays in the dark and under 455, 850, 1050 nm excitation. (f–h) Double RCs model schematics in the dark, and under low and high illumination power. (i and j) Temporal response of perovskite single crystal arrays under 155.4 mW cm⁻² at 0.85 Hz. (k) Noise current of perovskite single crystal array photodetectors in the dark at 5 V bias. (l) Responsivity and detectivity statistics of perovskite single crystal array photodetectors under 850 nm LED at 10 Hz. (m) Responsivity of reported 2D/3D lead-based perovskite photodetectors in near-infrared light. (n) Operating stability of Cu(GBAB)₂PbBr₄ and FAPbI₃ perovskite single crystal array photodetectors. (o) Parameter comparison (e.g., band gap) between Cu(GBAB)₂PbBr₄ and FAPbI₃ perovskite devices. Reproduced with permission.¹⁵⁴ Copyright 2019 WILEY-VCH GmbH.

While PDMS-templated monocrystalline arrays have demonstrated progress in mechanical stability, conventional synthesis routes for 2D perovskite single crystals face intrinsic bottlenecks, particularly in achieving wafer-scale production with precise nanoscale positioning. Existing methods—including solution drying, mechanical exfoliation, and epitaxial growth—are constrained to micron-scale crystals due to droplet size limitations and require excessive solution volumes or repetitive transfer steps, undermining scalability. Furthermore, random crystal placement and interfacial damage during electrode integration drastically reduce device yield for large-area photodetector (PD) arrays. To overcome these dual challenges, Lee et al.¹⁵⁵ developed an ultrasonic spray-coating strategy leveraging liquid-bridge transport effects, enabling wafer-scale (4-inch) synthesis of RGB-purple 2D PVSK nanocrystals and the high-throughput fabrication of PD arrays, as shown in Fig. 21a. The device exhibits linear I–V characteristics under UV illumination (Fig. 25b and c), showing a progressive current increase with higher light intensity. Notably, at an ultralow UV intensity of 0.003 μW cm⁻², the photodetector achieves a remarkable responsivity of 1.6 × 10⁶ A W⁻¹ and specific detectivity of 1.1 × 10¹⁶ Jones (Fig. 25d and e), surpassing most reported values for (PEA)₂PbBr₄-based UV detectors. The 200 nm electrode gap design plays a critical role in performance enhancement. As illustrated in Fig. 21g and h, the plasmonic gap modes and lightning-rod effect induced by nanoscale Au electrodes amplify local electromagnetic fields, with electric field intensity at electrode edges doubling under 365 nm illumination. These effects enable the detector to outperform conventional (BA)₂PbBr₄ single-crystal devices with 100 nm gaps in specific detectivity while maintaining comparable responsivity. The ultrasonic-assisted solution chemistry (USSC) technique contributes to defect suppression through conformal crystal-electrode contact (Fig. 21i) while preserving crystal integrity via bottom-contact architecture. Stable photoswitching characteristics are demonstrated in Fig. 21f, showing reproducible on/off cycling under varying UV intensities. Theoretical simulations in Fig. 21h reveal that surface roughness of Au electrodes further enhances light scattering through intensified lightning-rod effects in nanocrystals. The responsivity-specific detectivity correlation (Fig. 21i) highlights a 486-fold improvement over previous 2D perovskite photodetectors, establishing new benchmarks for R–D* performance parameters. This work addresses large-area integration challenges in 2D perovskite optoelectronics. The combination of scalable fabrication and nanoscale electrode engineering positions the technology as a promising candidate for artificial vision systems and array-level photonic applications.

Fig. 21 (a) Schematic of (PEA)₂PbBr₄ nanosheet arrays. (b and c) I–V curves of (PEA)₂PbBr₄ nanocrystal photodetectors under UV light and in the dark. (d and e) R and D* of (PEA)₂PbBr₄ nanocrystal PDs under UV light with 5 V bias, and performance parameters of previously reported PDs. (f) Photoresponse switching of (PEA)₂PbBr₄ nanocrystal PDs under UV light and in the dark with 5 V bias. (g) Schematic of the (PEA)₂PbBr₄ nanocrystal PD device structure under UV light. (h) Cross-section and electric field distribution of (PEA)₂PbBr₄ nanocrystal PDs under 365 nm light. (i) Comparison of D* and R between this device and reported PDs. Reproduced with permission.¹⁵⁵ Copyright 2025 Wiley-VCH GmbH.

Ultrasonic spray deposition has emerged as a scalable approach for fabricating high-density perovskite single-crystal arrays across large areas, yet its utility remains confined to monocompositional systems due to intrinsic limitations in dynamic compositional modulation. To overcome this spectral inflexibility, Yin et al.¹⁵⁶ engineered a mixed electrohydrodynamic printing (M-ePrinting) platform capable of digitally patterning bandgap-programmable perovskite micro/nanoarrays. Fig. 22a and b present the M-ePrinting mechanism, where synchronized voltage modulation across dual microfluidic channels enables precise control over precursor mixing ratios (Br⁻/I⁻), switching between pure CsPbBr₃/CsPbI₃ deposition and hybrid-gradient printing modes. This voltage-driven programmability achieves submicron resolution, as demonstrated in Fig. 22c–f, with printed features (dots and lines) surpassing conventional inkjet methods in precision. Spatially graded photoluminescence across electrodes 1–3 in Fig. 22g confirms Br/I ratio variations. The optoelectronic characterization shown in Fig. 22h reveals linear photocurrent enhancement at electrode 1 under 530 nm illumination, while Fig. 22i demonstrates a rapid transient photoresponse with 100/60.1 ms rise/fall times and an on/off ratio exceeding 10³. The quantitative analysis in Fig. 22j reports a specific detectivity of 3.27 × 10¹⁵ Jones for electrode 1. The composition-dependent photocurrent alignment in gradient line detectors is mapped via logarithmic I–V characteristics in Fig. 22k. Fig. 22l proposes spectral imaging through photodetector array readouts, supported by Fig. 22m, which includes optical photographs of gradient-line devices on glass and their layered architecture schematics. Finally, Fig. 22n and o validate the light-distribution sensing: mask-projected illumination patterns are spatially resolved via normalized photocurrent mapping, highlighting multispectral imaging capabilities.

Fig. 22 (a) Schematic of switching the “ON” channel at low driving voltage. (b) Fluorescent and SEM images of dots with different diameters (varying V_p, f, nozzle diameter, and nozzle–substrate distance). (c and d) Schematic of the driving waveform with continuous voltage rise and channel switching, and corresponding printed fluorescent patterns. (e and f) Schematic of the driving waveform with abrupt voltage rise and channel state switching, and corresponding printed fluorescent patterns. (g) Normalized PL spectra of a perovskite at electrodes 1, 2, and 3. (h) I–V characteristics of electrode 1 (dark vs. 530 nm illumination, varying intensity). (i) Transient photocurrent of electrode 1 under repeated on/off illumination. (j) Detectivity and on/off ratio of electrode 1. (k) Logarithmic I–V curves of gradient line photodetectors. (l) Schematic of spectral imaging via photodetectors. (m) Photographs of photodetectors on glass and schematic of the gradient line photodetector layer-by-layer structure. (n) Schematic of the gradient line photodetector array for light distribution detection. (o) Normalized current mapping by the image photodetector (patterned illumination via a shadow mask). Reproduced with permission.¹⁵⁶ Copyright 2024 Wiley-VCH GmbH.

The stacking method can break through the material limitations of a single preparation technology. It combines materials with significantly different physical/chemical properties through a “lamination” approach, enabling a full-band response from ultraviolet to terahertz and high spatial resolution. This provides support for verifying the expected advantages of perovskite stacked imagers in eliminating demosaicing color artifacts and achieving higher spatial resolution. As demonstrated by Sergey Tsarev et al.¹⁵⁷ an 8 × 8 × 3 stacked photodetector array and a 64 × 64 × 3 mechanically stacked thin-film transistor (TFT) detector array were fabricated. Fig. 23a illustrates the crossbar electrode layout for monochromatic pixel layers (R, G, B), enabling independent operation. Fig. 23b–d present normalized photocurrent histograms for RGB channels under red, green, and blue LED illumination, respectively, which align with spectral responsivity profiles, confirming retained color selectivity in pixelated arrays. Color accuracy was evaluated in the CIELAB space (designed to approximate human visual perception). Fig. 23e shows CIELAB distributions for ColorChecker patches: the blue patch yielded L = 4 ± 1, a = 15 ± 3, b = −35 ± 3; the green patch L = 29 ± 10, a = −30 ± 9, b = 29 ± 9; and the red patch L = 19 ± 3, a = 40 ± 4, b = 30 ± 4. These values are comparable to CFA and Foveon-type systems but exhibit slightly reduced accuracy due to optical/electrical crosstalk and ITO electrode misalignment. Nevertheless, the crossbar array validates monolithic integration for stacked imagers. Fig. 23f compares simulated outputs of Foveon and Bayer CFA sensors using the 8 × 8 × 3 perovskite array. For Foveon-like operation, all 194 active pixels were used, while the Bayer simulation deactivated two-thirds of the pixels per site (64 active pixels) to emulate geometric displacement. The Bayer sensor produced raw images with severe resolution loss from demosaicing artifacts, whereas the stacked design achieved higher light utilization and artifact-free imaging. Future advancements in perovskite lithography, vertical interconnects, and three-channel readout circuitry are critical for developing next-generation sensors with enhanced sensitivity and color fidelity.

Fig. 23 (a) Strip layout of electrode layers in each imager array stack. (b–d) Photocurrent histograms of RGB channels responsive to blue, green, and red LED light, normalized to the total response of the three channels. (e) Response distribution of the 8 × 8 × 3 strip array to a D50 light source reflected by the blue, green, and red patches of the ColorChecker. (f) Imaging experiment of a black-and-white ring pattern: left is the color artifact image of the Bayer CFA imager after the demosaicing algorithm; right is the image without color artifacts of the stacked perovskite imager. Reproduced with permission.¹⁵⁷ Copyright 2025 The Author(s).

In conclusion, the construction of large-area perovskite photodetector arrays can be realized based on traditional methods and materials, or through the development of new materials and approaches. However, the prepared perovskite arrays should feature high-resolution image sensing capability, homogeneous properties, and compatibility with other devices. With the in-depth research on perovskite materials and fabrication technologies, it is believed that the aforementioned issues will eventually be resolved, and perovskite-based large-area photodetector array devices will bring significant changes to future image sensing technologies.

6. Optical communication applications

Optical communication is a wireless communication method, which is an important supplement to traditional radiofrequency technologies in today's world where wireless spectrum resources are scarce.^25,27 As illustrated in Fig. 24a, this visible light communication system features a holistic architecture comprising three functionally integrated stages: (1) a transmitter module integrating modulation schemes with LEDs to convert electrical signals into optical waveforms, (2) free-space optical channel propagation, and (3) a receiver module utilizing photodetectors to reverse the conversion process through signal recovery and decoding algorithms. This end-to-end “electrical–optical–electrical” conversion framework addresses critical challenges in modern wireless communication through its inherent spectrum advantages and adaptive modulation capabilities.¹⁵⁸ Optical communication systems demonstrate multiple technical merits including abundant spectral availability, enhanced transmission efficiency, inherent security characteristics, electromagnetic interference resistance, and adaptive network configurability. Recent advancements in the field, as illustrated in Fig. 24b, have primarily focused on four key research directions: high-speed optical communication,¹⁵⁹ encrypted optical communication,¹⁶⁰ anti-interference optical communications¹⁶¹ and underwater optical communication.¹⁶² The following analysis systematically reviews recent progress in perovskite photodetector-enabled optical communication systems over the past few years.

Fig. 24 (a) Optical communication system architecture. (b) The application of optical communication in different directions.

6.1. High-speed optical communication

Photodetectors play a crucial role in optical communication systems, being vital for transmitting high-fidelity signals. Wang et al.¹⁵⁹ developed a high-performance flexible PD based on formamidinium-based perovskite, which exhibits fast response and excellent air stability. By introducing formamidinium chloride (FACl) as an additive, the quality and crystallinity of the thin film were improved. As shown in Fig. 25, this PD was integrated into a visible light communication (VLC) system as an optical signal receiver. The VLC features low cost, low energy consumption, high speed, high security, and electromagnetic interference resistance. Light-emitting diodes (LEDs) are used to generate high-speed pulse signals for information transmission, integrating lighting, communication, and control functions with wide applications in smart homes, intelligent transportation, and high-speed audio/video transmission. As illustrated in Fig. 25a, the VLC system consists of a transmitter and a receiver. The transmitter drives the LED, while the receiver processes signals. The driver converts computer data into high and low voltage levels, with the analog signals representing “1” and “0”. These voltage levels modulate the LED output, illuminating the PD to generate high and low photocurrents. The photocurrents are then amplified by a low-noise current-to-voltage preamplifier, and the voltage signals are transmitted to another driver, which converts them back into computer data. To simulate wireless data transmission, the character “SZUN” was modulated using case-sensitive American Standard Code for Information Interchange (ASCII) codes for each letter. High light intensity represents “1”, and low light intensity represents “0”. The signals are then sent to the PD, which reads them as high and low electrical signals. Finally, as shown in Fig. 25b, the electrical signals are demodulated into the letters “SZUN”. Fig. 25c displays the current signals of modulated optical messages received by the PD at different bit rates, indicating that the system can transmit data at a bit rate of 100 kbps. Given the PD's response speed, it should be capable of operating at 1 Mbps or higher, with the actual rate limited by the preamplifier's bandwidth. In summary, this work has demonstrated that PD is a highly promising material for high-speed optical communication applications.

Fig. 25 (a) Schematic diagram of a visible light communication system with a perovskite photodetector (PD) integrated with a plasmonic structure. (b) Electrical signal waveforms obtained by a single-chip microcomputer and PD. (c) Waveforms of digital data received by the PD at different transmission rates. Reproduced with permission.¹⁵⁹ Copyright 2022 Wiley-VCH GmbH.

Increasing the capacity of optical communication channels is another new method for achieving high-speed transmission. The photocurrent signal can be modulated by adjusting the wavelength of incident light. As shown in Fig. 26a, Cao et al.¹⁶³ fabricated a novel air-induced Cs₃BiBr₆/Cs₃Bi₂Br₉ bulk heterojunction (BHJ) photodetector (PD) with high-performance detection capabilities and dual-band photodetection functionality. As the optical signal receiver, this PD can output distinct photocurrent signals under ultraviolet (UV), blue light, or mixed light (UV + blue light). When illuminated by 365 nm (0.24 mW cm⁻²), 450 nm (2.05 mW cm⁻²), and mixed light, the output electrical signals are defined as “10”, “01”, and “11”, respectively, while the signal in darkness is defined as “00”. Details are shown in Fig. 26b: when a series of varying optical signals are inputted to the PD, corresponding electrical signals are generated. Specifically, a current of ≈ 100 pA represents “11”, ≈ 50 pA represents “10”, ≈ 5 pA represents “01”, and the signal in darkness is “00”. Finally, as illustrated in Fig. 26c and d, decoding these current signals using binary “0” and “1” digital signals yields the message “FDU I LOVE U”. Ke et al.¹⁶⁴ created a hybrid 2D/3D phase structure, which enhances the quality of Sn–Pb thin films, improves crystal orientation, suppresses trap-assisted recombination, and reduces the oxidation process of Sn²⁺, thereby achieving excellent environmental stability under atmospheric conditions. As shown in Fig. 27a, the improved Sn–Pb photodetector features a Pb content of 12%, the lowest compared with other literature, while exhibiting the highest detectivity of 8.86 × 10¹² Jones and the shortest response time of 684 ns. To demonstrate the practical applicability of this detector, the Sn–Pb photodetector was integrated as a signal receiver into a wireless optical communication system, as shown in Fig. 27b. A waveform generator outputs signals with the output power of a 910 nm LED, and the optical signals are controlled by a transmission switch. After propagating through free space, the optical signals are received by the PD, amplified by a transimpedance amplifier, and finally recorded by an oscilloscope. As shown in Fig. 27c and d, the highest data rates recorded for 665 nm and 904 nm links are 172.5 and 157.0 kbps, respectively, with bit error rates (BERs) far below the 7% hard-decision forward error correction (HD-FEC) threshold of 3.8 × 10⁻³ at 665 nm and 904 nm. Additionally, the eye diagram at 100 kbps is clearer and more open, indicating minimal intersymbol interference. However, at 180 kbps, the eye diagram narrows significantly, suggesting the device is approaching its limit. Fig. 27e illustrates the image transmission process of the optical communication system. First, a 600 × 600-pixel color image is decomposed into three monochromatic images defined as red, green, and blue (R, G, B) channels. These channels are then converted into optical signals with different waveforms based on pixel intensity values for sequential transmission. At the PD receiving end, the optical signals are decoded into pixel intensity values, reconstructed into R, G, and B channels, and finally recombined into the original color image. Fig. 27f shows the text information transmission process, where text is decomposed into signals with different waveforms via ASCII codes, and the received signals are reconstructed into complete information waveforms, demonstrating the optical communication system's ability to transmit text at a data rate of 25 kbps using this PD. Pan et al.¹⁶⁵ introduced single-layer hollow ZnO hemisphere arrays (ZHAs) as electron transport layers in perovskite photodetectors (PDs). The single-layer hollow ZHAs not only reduce reflection but also broaden the angle of effective incident light. Notably, they transfer the light field distribution from the ZnO/FTO interface to the perovskite active layer. These advantages facilitate carrier generation, transport, and separation, thereby enhancing light utilization efficiency. In practical optical communication, sensitive confidential documents cannot be transmitted via networks or USB flash drives. Optical communication effectively addresses the security issues of file transmission. The process of transmitting confidential documents via optical communication is illustrated in Fig. 28. These works have achieved high-capacity information transmission by leveraging the dual-band or multi-band photodetection capabilities of perovskite materials, significantly enhancing the speed of optical communication transmission. At the same time, they also demonstrate great potential in future quantum communication applications.

Fig. 26 (a) Schematic diagram of the Cs₃BiBr₆/Cs₃Bi₂Br₉ PD structure and corresponding signals generated under different wavelength lights. (b) Optical signals recorded by a Keithley 4200. (c and d) Decrypted codes and transmitted signals. Reproduced with permission.¹⁶³ Copyright 2022 Wiley-VCH GmbH.

Fig. 27 (a) Detection rate, response time and Pb content in this work compared with recently reported Sn–Pb NIR PDs. (b) Experimental setup for bit error rate performance, image and text transmission. (c and d) BER performance and eye diagrams at different data rates. (e) Image transmission using 12% Pb²⁺ PD and 910 nm LED light. (f) Waveform of the received signal during text transmission at a data rate of 25 kbps. Reproduced with permission.¹⁶⁴ Copyright 2025 Wiley-VCH GmbH.

Fig. 28 Schematic diagram of optical communication for transmitting confidential documents and structural diagram of the ZHA/CsPbBr₃ photodetector (PD). Reproduced with permission.¹⁶⁵ Copyright 2021 The Author(s).

A new method for increasing the information transmission capacity is achieved by utilizing the chirality of CPL.¹⁶⁶ Left-handed and right-handed CPL can be used as two independent channels to transmit information, doubling the rate of data transport compared with unpolarized light.^167–169 The development of CPL-based communication requires high-performance circularly polarized photodetectors and CPL sources. Unlike indirect methods of detecting and emitting CPL, chiral materials do not require additional optics; thus, circularly polarized photodetectors and light sources based on chiral materials are promising for integrated and flexible devices.^170,171

Two-dimensional perovskites have multiple phase structures and complex organic chain types. By altering the molecular chains of the organic layer in two-dimensional perovskites, the chiral structure of the perovskite can be easily regulated. Based on this, by combining the impressive optical and electrical properties of perovskites with chirality, chiral HOIPs should be promising for the detection of CPL.¹⁷² Currently, there are only a few reports on direct CPL detection from different material systems.²² A major challenge for CPL photodetectors is combining chirality (usually associated with organic molecules) and efficient charge transport (usually associated with inorganic semiconductors) in order to simultaneously enhance absorption anisotropy (g_abs) and photocurrent anisotropy (g_Iph). Therefore, chiral perovskites are especially promising, as they benefit from both aspects.

In recent years, there have been numerous efforts focused on improving g_abs and g_Iph. Liu et al. report a CPL detector based on quasi two-dimensional (quasi-2D) chiral perovskite films.¹⁷³ They find it is possible to generate materials where the circular dichroism (CD) is comparable in both 2D and quasi-2D films, while the responsivity of the photodetector improves for the latter. Given this, we are able to showcase a CPL photodetector that exhibits both a high dissymmetry factor of 0.15 and a high responsivity of 15.7 A W⁻¹. We believe our data further advocate the potential of chiral perovskites in CPL-dependent photonic technologies. Luo's group grew wide-bandgap (R-MPA)₂PbCl₄ on a silicon substrate.¹⁷⁴ The material's bandgap was calculated as 3.5 eV, which suggests a detection ability in the solar-blind ultraviolet region. Meanwhile, the CD peak was in the solar-blind ultraviolet region, making CPPD feasible. With the built-in field from the heterojunction, the g_res of the short current of 0.4 was significantly amplified. Li's group utilized the chirality and intrinsic anisotropy of the (S/R-MBA)₂PbI₄ crystal to enable the detector to simultaneously detect CPL and LPL, known as a full-Stokes polarimeter.¹⁷⁵ The polarization state can be described by four parameters, namely the total intensity S₀, the linear components S₁ and S₂, and the chiral component S₃. These parameters are calculated by adding the intensities of the different polarization components according to a certain rule. The polarimeter displayed an anisotropic I_light and g_res. Thus, the calibrated polarimeter could detect the incident light and provide current information for subsequent calculations. The average errors of S₁, S₂, and S₃ were calculated as 11%, 7.5%, and 26%, respectively.

Although the relevant theories and systems specifically for perovskite polarization-sensitive photodetectors are not mature enough yet, while the devices obtained from the research are still far from near practical application and mass production, it is encouraging that more and more outstanding work is moving the field forward. A relatively complete set of theories dedicated to the field of perovskite polarization detection is worth pursuing through experiments and calculations. Meanwhile, many strategies to improve device performance are continuously being proposed, and are proving to be feasible. The unique fundamental optoelectronic performance advantages of perovskite materials are far from reaching a bottleneck in the field.

6.2. Encrypted optical communication

While high-speed optical communication systems excel in data throughput, emerging security demands drive the integration of encryption functionalities at the hardware level. Recent advancements highlight the potential of tunable perovskite heterostructures for secure data transmission. As illustrated in Fig. 29a, a (BA)₂MAPb₂Br₇-MAPbBr₃ lateral heterostructure coupled with dual-beam irradiation enables four optical input states (00, 01, 10, 11) through laser modulation.¹⁶⁰ These modes correlate with photocurrent thresholds defined as dark current (<0.01 nA, “00”), low-intensity (0.1–1 nA, “01”), medium-intensity (5–20 nA, “10”), and high-intensity (50–100 nA, “11”) responses, as shown in Fig. 29c. The operational mechanism, detailed in Fig. 29b, relies on light-induced carrier generation within the heterostructure: the 3D perovskite governs low-frequency responses while the 2D Ruddlesden–Popper phase controls high-frequency dynamics. For signal encryption, photodetector-mediated optical-to-electrical conversion generates encrypted binary streams, exemplified in Fig. 29d. Decoding follows a hierarchical framework where photocurrent-modulated data undergo sequential conversion to ASCII codes and Unicode representations, and ultimately resolves into Chinese characters, as demonstrated in Fig. 29e. The bandgap-tunable nature of the heterostructure enhances security through dynamic spectral modulation, enabling wavelength-specific signal diversification. This capability doubles channel capacity while suppressing inter-channel crosstalk during multiband operation.

Fig. 29 (a) Operational schematic of a wavelength-tunable optical communication device structure. (b) Photocarrier transport dynamics in dual-band spectral detection mode. (c) Output signal differentiation through photocurrent/dark current intensity variations. (d) Semi-logarithmic I–t characteristics under 3 V bias with dual-wavelength optical switching. (e) 64-bit encoded output via dual-beam modulation, demonstrating Chinese character generation through a two-step ASCII–Unicode conversion protocol. Reproduced with permission.¹⁶⁰ Copyright 2024 Wiley-VCH GmbH.

Building upon the foundation of tunable perovskite heterostructures for secure data transmission, Fang et al. further validated the application potential of perovskite heterostructures in secure optical communication by developing an encryption system that integrates dual-beam modulation with dynamic key generation. As illustrated in Fig. 30a, this innovative system manipulates four optical input states through coordinated switching of 365 nm and 490 nm lasers, producing distinct photocurrent responses from three functional regions: the (BA)₂PbBr₄ domain, (BA)₂PbI₄ domain, and their heterojunction interface.¹⁷⁶ The experimental measurements in Fig. 30b and c reveal characteristic spectral selectivity – the (BA)₂PbBr₄ region exhibits >1 × 10⁻¹⁰ A photocurrent under 365 nm UV excitation with a negligible 490 nm response, while the (BA)₂PbI₄ region shows the reverse behavior. Fig. 30d demonstrates the heterojunction's unique superimposed response under dual-beam activation. The security framework detailed in Fig. 30e employs real-time generated dynamic keys to establish bijective mappings between alphanumeric characters and 4-bit binary sequences. As illustrated in Fig. 30f, this approach successfully encrypted the plaintext “FUDAN” into a secure 20-bit sequence 10111100101001000110 for optical transmission. The system's security is enhanced through bit-length scalability, with channel-independent multi-band operation analysis confirming exponential resistance improvement against brute-force attacks.

Fig. 30 (a) Schematic diagram of the BPI/BPB vdWHs optical communication. (b–d) Environment-dependent photoresponse characteristics under 3 V bias. (e) Secure key synthesis via the photonic-electronic hybrid encryption algorithm. (f) Dual-beam generated 20-bit data stream (“10111100101001000110”) demonstrating binary-to-character conversion. Reproduced with permission.¹⁷⁶ Copyright 2024 Wiley-VCH GmbH.

Expanding the practical implementation scope of perovskite-based photonic systems, Fig. 31 demonstrates a multifunctional platform that synergistically combines visible-light communication with high-precision real-time positioning through PMA₂PbI₄ photodetector integration.¹⁷⁷ As shown in Figure Fig. 31a and b, the architecture combines a microcontroller unit and transimpedance amplifier for photocurrent signal processing, enabling cloud-based data analysis and smartphone visualization through Bluetooth. Fig. 31c and d further depict the hardware integration of laser modulation and voltage comparator circuits for simultaneous communication and positioning. For data transmission tests, Fig. 31e demonstrates the system's ability to decode ASCII-coded messages at 1 kbps, exceeding human visual perception thresholds by a factor of 20. The bidirectional optical signals, modulated via laser on/off states, were successfully reconstructed on mobile devices, showcasing seamless light-to-electrical conversion. In positioning applications, Fig. 31f highlights the real-time tracking of PD-equipped targets under encoded LED illumination. When a toy car moved from Position A to B, the system updated location markers on smartphones within 50 ms, validating its potential for automotive navigation and wearable safety monitoring.

Fig. 31 (a and b) Schematic of bidirectional transmission (a) and real-time positioning (b). (c) Photographs of the implemented optical wireless communication system. (d) PMA₂PbI₄ PD-based optical communication system schematic. (e and f) The results and optical image of the bidirectional transmission (e) and real-time positioning (f). Reproduced with permission.¹⁷⁷ Copyright 2025 Elsevier Inc.

Another encryption approach involves utilizing the chirality of CPL. Objects composed of different materials typically reflect or scatter polarized light in distinct ways when exposed to natural light.¹⁷⁸ Therefore, the ability to distinguish CPL is crucial for object recognition under illumination, particularly for target detection in complex scenarios like anti-camouflage and anti-interference. Gu et al. proposed a tailored achiral–chiral cation mixing strategy to improve the intermolecular forces and out-of-plane octahedral tilt in the chiral perovskite, which effectively promotes chirality transfer, and van der Waals forces tuned vertical growth.¹⁷⁹ Furthermore, a chiral 2D perovskite-based CPL photodetector is constructed with balanced high absorption anisotropy (g_abs) and photocurrent anisotropy (g_Iph). Compared with materials obtained with pure chiral cations, the maximum g_abs of this chiral 2D perovskite increased by 7.33 times. The enhanced chiroptical activity and in-plane transport in vertically oriented chiral 2D perovskites endowed the self-powered CPL device with outstanding performance and a record g_Iph of 0.72. This work opens a reasonable paradigm of chiral 2D perovskite photodetectors in information encryption. The principle of CPL imaging encryption is illustrated in Fig. 32a. At low g_Iph, the contrast between the visualizations of RCPL and LCPL is minimal, making it challenging to extract effective information. However, high g_Iph enables high-fidelity visualization with excellent resolution, facilitating effective information transmission. To bolster the security of information transfer, we design a CPL conversion-controlled quick response (QR) code encryption system for the proof-of-concept imaging, as depicted in Fig. 32b. Under the illumination of LCPL and RCPL at 3.88 mW cm⁻², the QR code mask is projected onto the device, and the photocurrent at each point is recorded. It can be clearly seen from the 3D histogram of current in the local area that the photocurrent generated under LCPL illumination is higher than that under RCPL illumination, which appears as a brighter light blue in the light mapping. 2D current map images are obtained by extracting the photocurrent values. While no significant features are visible under RCPL illumination, switching the light source to LCPL enables the encrypted QR code to be fully visualized and read directly by a smartphone.

Fig. 32 CPL image for information encryption. (a) Schematic illustration of the CPL imaging encryption principle. (b) Proof of-concept encrypted QR code imaging of the device. Reproduced with permission.¹⁷⁹ Copyright 2024 Wiley-VCH GmbH.

These results underscore the potential of our 2D chiral perovskite-based CPL detector for information encryption applications, which accelerates the practical application of CPL detection technology.

6.3. Anti-interference optical communication

The accuracy and integrity of information transmission are crucial for optical communication applications. However, in the process of traditional information transmission, severe signal loss and ambient light interference are often encountered. Traditional methods rely on integrating complex optical and electronic systems, leading to a larger volume and higher cost of communication devices. As shown in Fig. 33a, the traditional optical communication system consists of a signal transmitter and a receiver unit. The transmitted signal is encoded and converted into a series of 0s and 1s in the ASCII, and the on–off state of the laser diode is controlled to transmit the signal. Then, the photodetector receives the signal and generates the corresponding photocurrent and dark current, which are restored to data signals by the driver and finally transmitted to the computer to restore the original information. The ASCII character codes are shown in Fig. 33b. To achieve anti-interference optical communication, Min et al.¹⁶¹ fabricated an asymmetric 2D–3D–2D perovskite photodetector. The device structure can offset the currents of the two photodiodes, and a single device can realize a frequency-selective light response. The perovskite layer of the device is prepared by a simple one-step spin-coating method and can exhibit a vertical 2D–3D–2D phase component distribution. By combining equal-amplitude electromotive forces in two opposite directions, the device output decays to zero under constant illumination. Due to the different response speeds of these reverse photodiodes, the device only responds near a specific frequency, which can be tuned by manipulating the 2D perovskite components. In the frequency-selective response range of 0.8–9.7 MHz, the device exhibits fast responses of 19.7/18.3 ns. As shown in Fig. 33c and d, although the anti-interference photodetector is interfered with by strong light with a light source intensity of up to 454 mW cm⁻², the character and video data can still be accurately transmitted. This result demonstrates the good anti-interference transmission capability of the device and fully meets the requirements of high-density information transmission. In addition, replacing the integrated system with a single device can greatly reduce the complexity and cost, thus providing greater flexibility and diversity for the design of free-space optical communication devices.

Fig. 33 (a) Schematic of the free-space optical communications system. (b) Laser driving signals during character transmission. Photos of the video data transmitted in (c) an indoor light environment and (d) intense light interference generated by a light emitting diode (LED). The encoding method for video transmission is a phase alternating line (PAL), and the laser intensity irradiated on the photodetector is 5.84 mW cm⁻². Reproduced with permission.¹⁶¹ Copyright 2024 Springer Nature.

An alternative approach is to leverage the high stability of CPL to enhance communication anti-interference capabilities. During transmission, particularly in free space or complex media, the polarization state of light may undergo random alterations due to scattering, refraction, and other effects—a phenomenon known as polarization mode dispersion or depolarization effects, which represents one of the primary sources of interference in communication systems. Utilizing circularly polarized light as an information carrier, in conjunction with detectors sensitive to its polarization state, can mitigate signal distortion induced by channel perturbations.

6.4. Underwater optical communication

While optical communication has achieved remarkable progress in terrestrial environments through advancements in transmission speed, data security, and anti-interference, its underwater implementation presents fundamentally new engineering paradigms. The extension of photonic networks into marine environments is becoming increasingly critical for oceanographic research, offshore energy systems, and ecological monitoring.¹⁸⁰ However, the harsh underwater environment also places stringent demands on photodetectors. First, the response of the photodetector should encompass the transmission window of the water to realize full-spectrum optical communication (<800 nm). Second, it should have good environmental stability, especially for moisture. Third, since visibility is usually low in underwater environments, photodetectors need to be sensitive to weak light and have strong low light detection capabilities. Therefore, it is important to find suitable photoactive materials and construct photodetectors. Yu et al.¹⁸¹ prepared a two-dimensional perovskite material by introducing stearamine, which brings superior waterproof performance, and successfully verified the underwater light detection capability of this photodetector. The underwater optical communication schematic is shown in Fig. 34a. Fig. 34b shows that the device has a low noise of 7.43 pA Hz^−1/2. Fortunately, low noise is critical for low-light detection, which ensures the effective detection of dim light in underwater environments. In optical communications, information is often modulated into optical signals with different intensities, frequencies, and waveforms, and hence the PD needs to recognize a variety of information. The I–t response of Fig. 34c confirms that the PD can effectively recognize light signals with different light intensities. Meanwhile, Fig. 34d–f show that for different light waveforms, ramp, pulse and sinusoidal signals can be accurately read out by the photodetector, successfully verifying the underwater light detection capability of two-dimensional perovskite photodetector.

Fig. 34 (a) Schematic diagram of the underwater communication experimental setup. (b) Noise current of the photodetectors and the testing system, respectively. (c) The photocurrent response of the photodetectors (under 532 nm, 2 V). Response of the photodetectors to (d) ramp, (e) pulsed and (f) sine-type light signals. Reproduced with permission.¹⁸¹ Copyright Springer Nature.

7. Conclusion and outlook

In summary, perovskite materials have emerged as a promising class of optoelectronic materials due to their outstanding characteristics, including high absorption coefficients, tunable optical bandgaps, superior charge carrier mobility, and simple fabrication processes. These exceptional properties have positioned perovskites as an ideal candidate for optical communication applications. This review systematically examines the research advancements in perovskite photodetectors, specifically analyzing their performance metrics, optoelectronic properties, device structures, compositional engineering, and applications in optical communication systems.

(1) Structural designs of perovskite photodetectors dictate their characteristic performance: photoconductors leverage gain mechanisms for high responsivity but suffer from high dark current, photodiodes achieve low driving voltage operation through built-in fields yet with compromised responsivity, while phototransistors enable gate-tunable ultrahigh photocurrent and responsivity at the cost of response time. The architectural evolution from lateral to vertical configurations and the integration of charge transport layers demonstrate how structural optimization can address fundamental trade-offs between responsivity, response time, and noise performance, providing clear design principles for developing next-generation perovskite-based photodetection systems tailored to specific application requirements.

(2) Fabrication strategy advancements of perovskite photodetector arrays address historical challenges in electrical crosstalk, inhomogeneity, and scalability: PDMS-templated patterning achieves high-fidelity single-crystal alignment with exceptional mechanical flexibility and ultra-low crosstalk, though scalability remains constrained by small-area compatibility and labor-intensive mold preparation. Ultrasonic spray-coating enables wafer-scale uniformity and rapid large-area deposition but suffers from limited crystal quality due to liquid-bridge transport effects, restricting the optoelectronic performance. Mixed electrohydrodynamic printing allows submicron-resolution patterning and real-time spectral tuning but demands stringent precursor viscosity control, faces coffee-ring-induced nonuniformity, and struggles with nozzle clogging in high-density arrays. Vertical stacking architectures transcend the material limitations of single-process systems by synergistically integrating layers with divergent physical/chemical properties, achieving gapless spectral coverage from ultraviolet to terahertz and high-resolution imaging without optical filter arrays, although challenges persist in thermal management, interlayer alignment precision, and readout circuit integration.

(3) Four novel application areas of perovskite photodetectors have been demonstrated: high-speed data transmission enabled by their ultrafast response characteristics, encrypted communication through dual-band heterostructures that exploit compositionally graded bandgaps for wavelength-selective signal encoding, anti-interference communication via 2D–3D–2D phase-engineered architectures where opposing carrier transport dynamics enable destructive current cancellation under static noise while preserving MHz-frequency signal selectivity, and underwater optical communication realized by employing two-dimensional perovskite materials featuring photoinduced hydrophobicity and broadband optical response characteristics. These applications collectively capitalize on perovskites’ exceptional defect tolerance, bandgap tunability, and high carrier mobility. Future developments may focus on optimizing environmental stability, expanding spectral response ranges, and integrating hybrid modulation schemes to address emerging requirements in quantum communication, space–air–ground–sea networks, and intelligent photonic systems.

The above highlights research progress in perovskite photodetectors for optical communications. However, current devices still exhibit insufficient photoelectric performance and limited applicability in optical communication systems compared with industrial requirements.

(1) Strategic recommendations to accelerate commercialization are proposed: the incompatibility of perovskite materials with traditional photolithography poses significant barriers to scalable array fabrication. Although alternative techniques like inkjet printing and PDMS template imprinting have demonstrated progress in constructing perovskite photodetector arrays, persistent challenges—including suboptimal crystallinity, limited spatial resolution, and poor scalability—hinder large-area manufacturing. Future advances should focus on non-destructive laser ablation for micron-scale pixel definition, combined with hydrophilic–hydrophobic surface patterning to enable the precise high-resolution self-assembly of perovskite films, while advancing solvent-resistant perovskite modifications compatible with micro/nano-processing to prevent polar solvent-induced degradation. While maintaining the performance of perovskite optoelectronic systems, achieve device miniaturization and large-area integration to fabricate high-resolution perovskite image sensors.

(2) The future application landscape of perovskite-based photodetectors is anticipated to bridge cutting-edge optoelectronic innovation with transformative societal technologies: by developing perovskite materials’ anisotropic optical responses to polarized light, next-generation photodetectors could achieve real-time polarization-state analysis for enhanced scene understanding in complex lighting environments or anti-counterfeiting detection systems, potentially synergizing with optical neural networks for edge-computing enhanced photonic signal preprocessing. Advanced imaging could evolve toward edge-computing empowered devices capable of real-time hyperspectral analysis for autonomous navigation and environmental monitoring, while ultra-flexible architectures might enable seamless human–machine interfaces through bio-integrated wearable platforms. In the field of optical communications, synergistic development leveraging perovskites’ high-speed and interference-resistant signal transmission capabilities could establish novel secure data transmission frameworks through their fiber-optic integration across 5G/6G networks and satellite constellations spanning space, air, terrestrial, and aquatic domains, with applications ranging from autonomous vehicle communications to remote human–machine interfaces and underwater optical links. The ultimate realization of these potentials hinges on harmonizing material stability with industrial-grade reliability, thereby transitioning laboratory breakthroughs into robust technologies that address global challenges in sustainable connectivity and precision sensing.

Author contributions

J. R. and H. S. conceived and designed the project, carried out research on the literature and drafted an initial version of the review. B. W., Q. C. and R. G. supported the literature collection. H. S., X. Z., Q. L. and Y. Z. provided revision suggestions and acquired funding for the research.

Conflicts of interest

There are no conflicts to declare.

Data availability

No data are included in this article since it is a review article.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant No. 52232006; 52472145; 52317233), and State Key Laboratory for Advanced Metals and Materials (Grant No. 2025-Z31).

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