A modulated heterojunction interface via ferroelectric P(VDF-TrFE) towards high performance quasi-2D perovskite self-powered photodetectors†

A self-powered photodetector (PD) based on quasi-2D perovskites (PVKs) provides natural advantages for long-term stable operation due to the battery-free character of the device and inherent stability of the quasi-2D PVK compared to its 3D form. However, sole dependence on the built-in potential brings fundamental challenges for efficient charge dissociation and transport. Here, we report a feasible solution to overcome challenges present in self-powered PDs by incorporating ferroelectric P(VDF-TrFE) into quasi-2D PVKs. The prominent effects observed in the F-PVK, (1) the suppression of the lower-n phases and (2) the formation of the favorable energy band alignment, lead to the suppression of the dark current as well as enhanced charge dissociation and transport, which are primary factors required for self-powered PDs. As a result, the self-powered PD with P(VDF-TrFE) demonstrates a responsivity of 0.405 A W⁻¹, detectivity of 4.90 × 10¹³ Jones, EQE of 94.4%, and rise/fall time of 6.67/1.77 μs. In particular, the EQE and response time are comparable to the highest values reported for the PVK-based PDs so far. Furthermore, the PD with P(VDF-TrFE) exhibited higher stability, maintaining 95% of its initial photocurrent whereas that of the reference PD dropped to 88% after 70 days of storage.