Ultralow Voltage Bias-Switchable Perovskite Photodetectors Enabled by Interfacial Deep-Trap Engineering.

Abstract

Photodetectors capable of switching between photovoltaic (PV) and photomultiplication (PM) modes are highly desirable for adaptive sensing and optical communication, but integrating high sensitivity with high speed remains a fundamental challenge. Here, we overcome this trade-off by demonstrating a bias-switchable perovskite photodetector (PD) based on a quasi-two-dimensional perovskite via interfacial deep-trap engineering. By tailoring interfacial trap states at the perovskite interface, trap-enabled barrier narrowing and facilitated hole injection are activated at low bias, producing high gain without sacrificing speed. The optimized device operates in self-powered PV mode at 0 V, delivering a detectivity (D*) of 1.12 × 1011 Jones and fast rise/fall times (τr/τf) of 2.10/1.21 μs. Under an ultralow reverse bias of -0.3 V, it achieves a record-high external quantum efficiency exceeding 2100%, a D* of ∼1.7 × 1012 Jones, and μs-level τr/τf in PM mode. Compared with state-of-the-art dual-mode PDs, our approach achieves the lowest bias and μs-level response simultaneously. This bias-switchable perovskite PD integrated with PV and PM dual-mode capability eliminates the need for external amplification circuits and provides rapid detection, highlighting significant potential for applications in portable sensing and dynamic optical environments.