Perovskite Photodetectors With Customizable Frequency Response

ABSTRACT Photodetectors in emerging optoelectronic systems are increasingly required to deliver application‐defined transfer characteristics rather than merely high responsivity or fast response. Existing response‐engineering strategies mainly operate in the wavelength or intensity domains, but often increase source‐side complexity, power consumption, and sensitivity to optical‐path fluctuations. Here we introduce a frequency‐centric strategy for response modulation. By combining a time‐integrated‐charge‐based alternating‐current‐to‐direct‐current (AC–DC) mapping with continuous tuning of the built‐in electric fields across heterojunction regions with antagonistic photoresponses, the transfer function becomes customizable in the frequency domain. Using lead‐halide perovskites as a model platform, we demonstrate bipolar responses for image‐processing, nonlinear responses for neuromorphic activation‐function emulation, and selective responses for anti‐interference free‐space optical communication. The selective‐response device suppresses stray illumination by more than three orders of magnitude, while the transmitter can be implemented using a conventional laser diode driven by a function generator. The extension of this strategy to PbS and PbI 2 ‐based systems supports its material generality, indicating a general route to photodetectors with application‐defined response characteristics.