Alternating Current Photodetectors in Hybrid Perovskites with Modulated Oscillation Frequency

Growing interest has emerged in the alternating current (AC) photovoltaic effect, distinct from the traditional direct-current (DC)-based photovoltaic effect. This effect arises from the relative movement and reorganization of quasi-Fermi levels at material interfaces when light is toggled on or off. In this study, a halide-perovskite-based photodetector is successfully fabricated, demonstrating the AC photovoltaic effect through oscillation frequency modulation and light-chopping-induced optical frequency tuning. For the first time, in sample impedance and the AC photovoltaic effect in this system are observed changes. Under specific conditions—light-chopping frequency of 4 Hz, 0 V bias, 500 mV oscillation voltage, and resonance frequency of 16.8 MHz—a distinctive AC photoresponse at 405 nm wavelength is confirmed. This phenomenon is attributed to the influence of oscillation frequency on charge carriers, impacting electron dynamics such as capture and emission within the energy bands. The developed photodetector exhibits efficient responses to optical frequency and light intensity changes, aligning with the characteristics of conventional AC photodetectors. This work establishes a novel pathway for high-performance AC photodetectors with superior sensitivity and tunability, surpassing traditional DC devices, and sets the foundation for further advancements in optoelectronic applications.