High-performance self-powered CsPbBr3 perovskite photodetector with ZTO electron transport layer

Abstract

In recent years, self-powered perovskite photodetectors (PDs) have received much attention due to their numerous advantages, including self-powered characteristics, excellent sensitivity, and fast response time. However, the process of fabricating perovskite films is prone to operational instability, resulting in low-quality films, elevated impurity levels, and numerous surface defects. In this thesis, I aim to present the fabrication and characterization of self-powered photodetectors (PDs) based on CsPbBr3 perovskite. The self-powered PDs were fabricated by solution-based method with zinc-tin oxide (ZTO) electron transport layer (ETL) with different spin-coating cycles. The choice of ZTO as ETL was motivated by its excellent electron mobility and good energy band alignment with the perovskite material, which in turn promotes efficient carrier extraction and transport at the interface of the perovskite film. The dark current of the CsPbBr3 PD fabricated using ZTO as ETL is significantly lower compared to the pristine CsPbBr3 photodetector. This improvement can be attributed to the improved quality of the CsPbBr3 films with larger grain size, increased coverage, and effective passivation of the trap states within the perovskite films. In this study, fabricated all-inorganic ZTO ETL/CsPbBr3 PD has a decay time of 0.11 s, an on/off ratio of 66.39, and a specific detectivity of 3.65x1010 J. The performance of the prepared ZTO ETL/CsPbBr3 heterojunction PD is improved by a factor of 50, 63, and 178, respectively, compared to the pristine CsPbBr3 PD.