An electron-dominated lateral photovoltaic effect in ZnO-based perovskite heterojunctions and its performance tunability by pyroelectric effect

Abstract

The increasing demand for high-performance position-sensitive detectors (PSDs) is driven by advancements in digitization and automation. Zinc oxide (ZnO), a well-established electron transport material, exhibits significant promise in this field, particularly due to its non-centrosymmetric structure, which enables a pyroelectric effect (PE) to modulate the photoresponse. However, the potential of ZnO-based PSDs and their lateral photovoltaic effect (LPE) remains largely unexplored. In this work, we fabricated a ZnO/CH₃NH₃(MA)PbI₃ heterojunction, and investigated its LPE responses and PE modulation properties under nonuniform illumination. The heterojunction demonstrates a substantial position sensitivity (PS) of 166.67 mV mm⁻¹, attributed to the efficient separation and diffusion of photo-generated electrons. The incorporation of the PE significantly enhances this PS to an impressive 705.33 mV mm⁻¹, representing a boost of 423.20%, with a response time of 63/80 ms. This enhancement is a result of the PE-driven promotion of electron separation and transport. Additionally, we propose a novel imaging system based on this PSD, leveraging both the inherent LPE responses and PE-enhanced LPE responses, potentially enabling wavelength-resolved imaging. Furthermore, the PSD operates effectively with an electrode distance ranging from 0.2 to 1.4 mm. While both the LPE response and its PE enhancement decrease with increasing electrode distance, a substantial PE-enhanced PS of 138.67 mV mm⁻¹ is still achieved, compared to a normal PS of 86.00 mV mm⁻¹. This tunability can be exploited to modulate imaging resolution. This work provides valuable insights into electron-dominated LPE, PE modulation and their applications in PSDs.