Decoupling Charge Compensation in Strongly Correlated Oxides via Element Doping

Carrier-type control in strongly correlated oxides is often determined by intrinsic vacancies instead of doping. However, independent modulation is fundamentally limited by the charge compensatory coupling between these defects. To overcome this challenge, this study proposes a strategy of lithium (Li) doping in bismuth ferrite (BiFeO₃) to decouple the interdependence between oxygen vacancies (VO) and bismuth vacancies (V_Bi). First-principles calculations reveal Li⁺ substitutes VO's charge compensation role for V_Bi and suppresses VO formation by stabilizing lattice oxygen, while concurrently facilitating V_Bi formation and ionization, boosting hole concentration. Experimentally synthesized Li⁺-doped BiFeO₃ film exhibits significant performance improvement, with a photocurrent density 2.5 times that of the undoped film. They also exhibit excellent stability, retaining 90% of their initial performance after 20 h of continuous reaction, and enhancing the production rate of H₂O₂. This work presents a Li⁺-doping strategy to decouple VO and V_Bi, offering an approach for precise carrier type and concentration manipulation in metal oxides.