Ultrastable Lead-Free Double Perovskite Photodetectors with Imaging Capability

Recently, the halide perovskites have increasingly received attention because of their superior capabilities in photodetector applications. However, the well-known instability and lead-toxicity are two major obstacles for their commercialization and practical applications. In this work, self-powered photodetectors based on solution-processed double perovskite Cs₂AgBiBr₆ films are fabricated for the first time. Owing to the high material integrity of Cs₂AgBiBr₆ and efficient interfacial charge transfer from perovskite to the underlying electron-quenching layer, the photodetector demonstrates excellent performances. Especially, the unencapsulated device demonstrates a good working stability in the open air. Typically it has the ability to endure a high temperature of 373 K for 10 h continuous running, demonstrating a good temperature resistance. In addition, after 3-month storage in open air, the photodetection capability of the device can almost be maintained. By deploying the photodetector as a point-like sensing pixel, high-resolution imaging patterns are acquired, which is the first report on imaging applications of lead-free perovskite photodetectors. The obtained results suggest that the lead-free double perovskite Cs₂AgBiBr₆ is potentially an attractive candidate to be applied in high-efficiency and stable photodetectors that can be employed in optical imaging.