Improved performance of perovskite photodetectors based on a solution-processed CH3NH3PbI3/SnO2 heterojunction

Abstract High-performance perovskite photodetectors are demonstrated based on a CH 3 NH 3 PbI 3 /SnO 2 heterojunction on glass substrates. This heterojunction can be fabricated with a facile and low-cost spin-coating method at low temperature. The photoresponse of the photodetectors is dramatically increased with such a heterojunction structure. The optimized device shows a responsivity of 1.65 A/W, which is more than twice to the reference device with a CH 3 NH 3 PbI 3 layer on bare glass (0.67 A/W). Besides, the device also exhibits a fast response speed with rise and decay times both of about 10 ms. The inserted SnO 2 layer not only improves the morphology and crystallinity of the CH 3 NH 3 PbI 3 films but also increases the dissociation efficiency of the excitons in CH 3 NH 3 PbI 3 through electron transfers from CH 3 NH 3 PbI 3 to SnO 2 , which increases the hole collection efficiency due to the suppressed charge carrier recombination probability of the devices and prolonged lifetime of the holes in CH 3 NH 3 PbI 3 films.