High-Performance Lead-Free Layered-Perovskite Photodetectors and Bipolar Transistors by Solvent Engineering

Halide Sn-based perovskite is a promising candidate to replace Pb-based perovskites due to its low toxicity and compatibility with horizontal charge transport in lateral detectors. However, the photodetector performance of halide Sn-based perovskites is often suppressed by poor film quality and "self-doping" effect in the process of film fabrication. In this study, uniform and dense Sn-based layered-perovskite films are obtained by solvent engineering. The fabricated photodetector has a high responsivity of 2.16 × 103 A/W, a high detectivity of 5.16 × 1013 Jones, and the ultrafast response of microsecond level in ambient conditions. Furthermore, the resulting field-effect transistor shows a rare bipolar transport behavior, and the mobilities of electrons and holes both exceed 0.08 cm2 V–1 s–1. Besides, a low threshold voltage and a small subthreshold swing of the transistor are achieved. This achievement provides valuable guidance for the development and application of Sn-based layered-perovskite materials and lays a foundation for the development of high-performance lead-free electronic devices.