Improved performance of perovskite photodetectors with a hybrid planar-mixed heterojunction

Abstract

Improved performance of lateral perovskite photodetectors is demonstrated based on a hybrid planar-mixed heterojunction structure, which comprises a CH3NH3PbI3:PC61BM ([6,6]-phenyl-C61-butyric acid methyl ester) bulk heterojunction on a planar SnO2 layer. The photodetector with an optimized PC61BM doping concentration shows a photocurrent more than three times to that device without a PC61BM doping or without a planar SnO2 layer, confirming that the hybrid planar-mixed heterojunction structure plays an important role in improving the performance of the devices. The photodetector exhibits a responsivity higher than 2 A W−1 in a wide range from ultraviolet to near infrared with a maximum one of 9 A W−1 at 315 nm. The improved performance is not only attributed to the increased electron transporting ability and the dissociation probability of excitons and/or electron-hole pairs in perovskite, but also to the growth of compact perovskite films with decreased grain boundary and hence the increased charge carriers transporting efficiency due to the introduction of PC61BM.