High Speed and Stable Solution-Processed Triple Cation Perovskite Photodetectors

Photodetectors, which can convert light signals into electrical signals, are important opto-electronic devices in imaging, optical communication, biomedical/biological sensing, and so on. Here a solution-processed photodetector based on the triple cation perovskite is demonstrated. The perovskite photodetectors show a high detectivity, high speed, as well as excellent environmental stability. Operating at a low voltage bias of 2 V, the photodetectors exhibit a large on/off ratio of 10⁵, high specific detectivity of ≈10¹³ Jones, and a fast photoresponse with 3 dB bandwidth up to 0.82 MHz. Further analysis demonstrates that such performance originates from the modulated Schottky barrier height by illumination. The barrier suppresses dark current without any illumination, but it can be effectively lowered under illumination, thus resulting in a more efficient charge extraction and collection. The results demonstrate a great potential of triple cation perovskite in photodetection and provide a route to achieve high performance devices.