Transient Photocurrent Response in a Perovskite Single Crystal-Based Photodetector: A Case Study on the Role of Electrode Spacing and Bias

Transient photocurrent is a widely applied characterization technique to probe the charge-carrier photogeneration and extraction dynamics in perovskite optoelectronic devices. Despite the large number of studies on the properties of perovskite single-crystals (SCs) photodetectors (PDs), the underlying mechanism that governs the spectral line shape of transient photocurrent is not fully understood. Here, methylammonium lead bromide (MAPbBr(3))SC based PDs are used to study the effect of different electrode spacing and bias on the transient photocurrent response under blue and green light irradiation. The observed differences in the spectral line shape of the transient photocurrent are explained using three-step carrier transport model, which reveals the occurrence of carrier trapping and a recombination process in MAPbBr(3) SC. The findings are further corroborated by intensity-dependent photocurrent and impedance spectroscopy analysis of the resulting PDs. This work provides a basic insight into the origin of the different behavior of transient photocurrent response under variable electrode distance, bias, and irradiance light, which is expected to help to further understand and optimize the performance of perovskite based PDs.