Progress in DFT Studies of BiOF: Crystals, Defects, Doping and Heterojunctions.

BiOF has emerged as a promising functional material for photocatalysis, electrochemical energy storage, and ion adsorption due to its unique layered structure, excellent chemical stability, and tunable electronic properties. Density functional theory (DFT) calculations provide in-depth theoretical insights into the crystal structure, intrinsic defects, doping modification, and heterostructure construction of BiOF. This review systematically summarizes the recent DFT research progress of BiOF systems. Computational results reveal the lattice characteristics, bandgap features, built-in electric field distribution and facet anisotropy of BiOF, and highlight the critical influence of Bi semicore states on structural relaxation and electronic modulation. Defect engineering of bismuth and oxygen vacancies can effectively optimize band structure, accelerate carrier separation and improve catalytic performance. Cation and anion doping introduce impurity energy levels to narrow the bandgap and broaden the visible-light response range. Various BiOF-based heterostructures with different band alignment modes are analyzed, and the interfacial built-in electric field dominates charge separation, while excessive formation energy and unfavorable charge transfer still restrict material optimization. This work provides a systematic theoretical reference for the rational design and performance improvement of high-efficiency BiOF-based materials.