Optimized photoelectric characteristics of MAPbCl₃and MAPbBr₃composite perovskite single crystal heterojunction...

MAPbBr₃single crystal (SC) thin layer was successfully grown on MAPbCl₃SC substrate to form perovskite SC heterojunction. Planar structure electrodes are deposited by thermal evaporation on the surfaces of MAPbCl₃, MAPbBr₃, 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 MAPbCl₃and MAPbBr₃, possessing relatively low dark current (∼300 nA), which is comparable to the dark current of MAPbCl₃, but very high photocurrent (∼3500 nA), which is equivalent to the photocurrent of MAPbBr₃. Rather than the photocurrent overshot and decay occurring at the exposure of light illumination in the MAPbBr₃device, 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 MAPbCl₃device and three times that of MAPbBr₃device. Furthermore, the detectivity of the heterojunction device reaches as high as∼7×1011 Jones, an order of magnitude higher than MAPbCl₃and MAPbBr₃. The excellent characteristics of SC heterojunction further expand the practical application prospect of perovskite materials.