AC‐Field‐Induced Reversible Photoluminescence Modulation in 2D Metal Halide Perovskites

Abstract 2D Ruddlesden‐Popper (RP) phase perovskites are promising materials for optoelectronic devices due to their unique properties and environmental stability. In this work, fully electrical, dynamic, and reversible modulation of photoluminescence (PL) intensity in RP‐phase perovskite nanosheets at room temperature is achieved for the first time using alternating current (AC) electric fields. A capacitor structure with (PEA) ₂ PbI ₄ nanosheets and HfO ₂ enables significant PL quenching, with the largest modulation amplitude reported to date. The degree of quenching depends on AC field parameters, including amplitude, frequency, waveform, and inter‐electrode phase difference. Temperature‐dependent measurements and impedance spectroscopy (IS) reveal that the PL quenching originates from an interfacial polarization field formed by AC‐driven ionic displacement and directional accumulation, which perturbs exciton recombination. This work provides insights into ion migration and electric field interactions in 2D perovskites. It also establishes an energy‐efficient method for tuning optoelectronic properties, offering a practical route for developing adaptive photonic systems and low‐power, electrically tunable devices.