Ga-doped ZnO nanorod scaffold for high-performance, hole-transport-layer-free, self-powered CH3NH3PbI3 perovskite photodetectors.

Abstract The use of aligned one-dimensional nanostructures as scaffolds in organic-inorganic hybrid perovskite photodetectors (PDs) has attracted significant attention due to their large surface area-to-volume ratio and efficient electron transport capability in the radial direction. Here, we report CH 3 NH 3 PbI 3 (MAPbI 3) perovskite photodetectors (PDs) with Ga-doped ZnO nanorods (GZO NRs), prepared by the water bath method, as a scaffold-structure electron transport layer (ETL). Our MoO 3 hole transport layer (HTL) based perovskite PDs using GZO NRs as a scaffold showed a larger light/dark current (I ph / I dark) ratio, higher responsivity and detectivity than those of the undoped ZnO NRs/MAPbI 3 devices at zero bias. These enhancements are attributed to the incorporation of Ga atoms into the ZnO NRs, which reduce the density defect states of ZnO NRs and improves the performance of MAPbI 3 perovskite PDs. In addition, by taking advantage of the GZO NRs scaffold structure, a HTL-free perovskite PD was prepared by using graphite electrodes. The graphite-connected device shows self-powered PD performances with an I ph / I dark ratio of ~2.5 × 103, responsivity of above 0.3 A/W and detectivity of 1.3 × 1012 Jones, all of which are comparable with those of MoO 3 HTL based perovskite PDs. Graphical abstract Our MoO 3 hole transport layer (HTL) based perovskite PDs using GZO NRs as a scaffold showed a larger light/dark current (I ph / I dark) ratio, higher responsivity and detectivity than those of the undoped ZnO (UZO) NRs/MAPbI 3 devices at zero bias. In addition, a HTL-free perovskite PD prepared by using graphite electrodes shows self-powered PD performances with an I ph / I dark ratio of ~ 2.5 × 103, responsivity of above 0.3 A/W and detectivity of 1.3 × 1012 Jones, all of which are comparable with those of MoO 3 HTL based perovskite PDs. fx1 Highlights • The perovskite photodetector with GZO NRs scaffold showed a larger I ph / I dark ratio, higher responsivity and detectivity than those of the undoped ZnO devices at zero bias. • The enhancements are attributed to the incorporation of Ga elements in ZnO NRs, which reduces defect states of ZnO nanorods. • A HTL-free perovskite PD shows highly self-powered performances with the I ph / I dark ratio of ~2.5 × 103, responsivity of above 0.3 A/W and detectivity of 1.3 × 1012 Jones. [ABSTRACT FROM AUTHOR]