Optimized photoelectric characteristics of MAPbCl3 and MAPbBr3 composite perovskite single crystal heterojunction photodetector

MAPbBr(3) single crystal (SC) thin layer was successfully grown on MAPbCl(3) SC substrate to form perovskite SC heterojunction. Planar structure electrodes are deposited by thermal evaporation on the surfaces of MAPbCl(3), MAPbBr(3), and SCs heterojunction, respectively to evaluate their photoelectric performance. The SC heterojunction device exhibits excellent unidirectional conductivity in the voltage-current curves. Meanwhile, the current-time curves prove that SC heterojunction devices can effectively utilize the advantages of MAPbCl(3) and MAPbBr(3), possessing relatively low dark current (similar to 300 nA), which is comparable to the dark current of MAPbCl(3), but very high photocurrent (similar to 3500 nA), which is equivalent to the photocurrent of MAPbBr(3). Rather than the photocurrent overshot and decay occurring at the exposure of light illumination in the MAPbBr(3) device, the photocurrent is extremely stable without overshot and decay in the SC heterojunction device. The light-to-dark ratio of the SC heterojunction device is twice that of MAPbCl(3) device and three times that of MAPbBr(3) device. Furthermore, the detectivity of the heterojunction device reaches as high as similar to 7 x 10(11) Jones, an order of magnitude higher than MAPbCl(3) and MAPbBr(3). The excellent characteristics of SC heterojunction further expand the practical application prospect of perovskite materials.

Automated summary

A perovskite single crystal heterojunction was successfully formed by growing MAPbBr(3) single crystal thin layer on a MAPbCl(3) single crystal substrate. The heterojunction device exhibits excellent photoelectric performance, with low dark current, high photocurrent, and stable photocurrent compared to MAPbCl(3) and MAPbBr(3). Furthermore, the heterojunction device has a higher light-to-dark ratio and detectivity than MAPbCl(3) and MAPbBr(3).