Electron Reservoir Enabled Oxygen Vacancies Engineering for Charge Transport and Defect‐Mediated Relaxation

ABSTRACT

Oxygen vacancy (V _o ) engineering is crucial for regulating electronic structures and charge responses in functional materials, yet V _o induced localized states can enhance charge localization and limit the participation of charge carriers in charge‐response processes, resulting in insufficient charge supply for defect‐mediated electronic responses. Developing a strategy that alleviates charge‐supply limitation while preserving the electronic modulation enabled by localized defect states remains challenging. To address this challenge, we investigate electronic compensation of V _o related states using Mo ₂ C MXene/MoO _3‐x heterostructures constructed through an in situ redox method, in which Mo ₂ C MXene serves as the electron donating component and tunable V _o in MoO _3‐x acts as defect‐state regulation centers. Density functional theory (DFT) calculations and experimental results reveal that electron compensation from Mo ₂ C MXene promotes defect‐mediated charge response and dielectric relaxation, thereby alleviating charge supply limitations associated with localized vacancy states and enabling systematic modulation of defect electronic structures. This defect‐state regulation is further demonstrated in electromagnetic wave (EMW) absorption, achieving an effective absorption bandwidth (EAB) of 7.28 GHz and a minimum reflection loss (RL _min ) of −51.49 dB. This work provides insight into defect state‐mediated charge regulation and provides a perspective for defect engineering toward tailoring of electronic and charge response behavior.