Self-powered narrowband visible-light photodetection enabled by organolead halide perovskite CH3NH3PbBr3/p-Si heterojunction

Abstract

In this work, we have reported self-powered narrowband visible-light photodetectors based on organolead halide perovskite CH3NH3PbBr3 (MAPbBr3)/p-Si heterojunctions, which were prepared by growing MAPbBr3 microcrystals on the p-Si substrate using a room-temperature antisolvent-assisted crystallization method. Morphological, structural, and optical investigations showed that the as-grown MAPbBr3 microcrystals possessed a high crystalline quality. Electrical characterizations showed that the hetero-pn junction was formed within the MAPbBr3/p-Si heterojunction. Thanks to the high crystalline quality of MAPbBr3 microcrystals, the as-fabricated heterojunction photodetectors operating under a bias voltage of 0 V exhibited a high on-off ratio of ∼5.3 × 105, a narrow photosensitivity spectrum with the full width at half maximum of 18.2 nm, a high photoresponse speed with the rising/falling time of 115.7/53.4 ms, and excellent stability to visible-light signals. Finally, the photodetection mechanism was proposed. It showed that the observed narrowband photodetection was attributed to the self-filtering effect caused by the thick MAPbBr3 microcrystals. The results presented in this work will provide valuable strategies for the fabrication of self-powered narrowband visible-light photodetectors in the future.