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

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 10(4). 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.