In situ formation of CsPbBr3/ZnO bulk heterojunctions towards photodetectors with ultrahigh responsivity

Abstract

In this study, we report a facile solution method to construct a high-performance photodetector (PD) based on in situ formed CsPbBr₃/ZnO bulk heterojunctions. Owing to the promoted charge separation and transfer at heterojunctions, the photocurrent of the CsPbBr₃/ZnO PD is greatly enhanced as compared to the pristine CsPbBr₃ PD, and ZnO can passivate the perovskite to eliminate trap states on its surface and grain boundaries, which favors the charge carrier transport. As a result, the CsPbBr₃/ZnO PD exhibits an ultrahigh responsivity of 358 A W⁻¹ and a high on/off ratio of 10⁴. In addition, the device shows a fast photoresponse (rise time: 0.88 ms and decay time: 1.53 ms). It is also revealed that the device has excellent stability after storage for 1 month in air. By deploying the PDs as an integrated detector array, we can acquire clear images. We believe that this work can inspire the facile and low-cost fabrication of high-performance perovskite-based PDs for imaging applications.