Broad-spectrum (UV-vis-Nir) high-performance photodetector based on perovskite/quantum dot tandem heterostructure

Abstract

Organic–inorganic hybrid perovskite materials demonstrate significant potential in photodetection due to their outstanding optoelectronic properties. However, their inherent structural characteristics result in limited light response in the ultraviolet and near-infrared bands (>800 nm), severely limiting their applications in multiband imaging, optical communications, and biomedical detection. This study extended the spectral response range of devices from the ultraviolet to the short-wave infrared region (1000–1600 nm) by constructing a heterojunction structure between PbS colloidal quantum dots (CQDs) and FA_0.9Cs_0.1PbI₃ perovskite (PSK) thin films. The results indicate that a Type-II band alignment at the PbS/perovskite heterojunction interface promotes efficient separation and transport of photo-generated carriers. The fabricated ITO/SnO₂/PbS/FA_0.9Cs_0.1PbI₃/Au device achieved responsivities of 82.5 mA W⁻¹ at 280 nm (UV), 319.3 mA W⁻¹ at 520 nm (visible), and 63.3 mA W⁻¹ at 1550 nm (near-IR), with specific detectivities (D*) of 4.3 × 10¹⁰, 1.7 × 10¹¹, and 3.3 × 10¹², respectively. This heterojunction detector exhibits fast response characteristics (rise/fall time: 160 ms/80 ms) under a 0.6 V bias. This study provides a novel material system and device design strategy for developing high-performance, low-cost multiband photodetectors.