High-gain broadband organolead trihalide perovskite photodetector based on a bipolar heterojunction phototransistor

Both a favorable material and designed structure are essential for a high-performance photodetector. For the excellent physical properties of organolead trihalide perovskites, with CH3NH3PbI3 films serving as a base layer, a bipolar heterojunction phototransistor-type perovskite photodetector is proposed. Benefiting from this bipolar heterojunction structure, which is characterized by high gain and low work voltage, an optimized device exhibits high performance with a photoresponsivity of 125 AW−1 and an external efficiency of 3.62 × 104% at 427 nm with a low work voltage of 0.7 V. Additionally, such phototransistors have a broad photoresponsivity from 360 to 820 nm. These results demonstrate that the bipolar heterojunction phototransistor, which is widely used in inorganic materials, is a promising structure for organolead trihalide perovskite optoelectronic devices, paving a new way for developing high-performance photodetectors.