Antimony-Doped Violet Phosphorus Nanosheets: Band Gap Engineering for Enhanced Photodynamic Effect and Efficient Antibacterial Activity

Bacterial infections pose a severe threat to public health worldwide, and overuse of traditional antibiotics induces bacterial resistance, limiting the efficacy of conventional therapies. Two-dimensional violet phosphorus nanosheets (VPNS) have emerged as promising photodynamic antibacterial materials owing to their unique layered structure and light-responsive capability. However, the inherent wide band gap of VPNS restricts photogenerated electron transition and reactive oxygen species production, resulting in unsatisfactory photodynamic therapy efficiency, which severely hinders their biomedical applications. To address these limitations, a facile antimony (Sb) doping strategy is developed to modulate the electronic band structure of VPNS for significantly boosted photodynamic antibacterial performance. As a congener of phosphorus, Sb possesses excellent optical and electrical properties, which can effectively optimize the photoelectric characteristics of VPNS. Results confirm that Sb doping narrows the band gap of VPNS from 1.91 to 1.42 eV and boosts reactive oxygen species (ROS) generation by 2.3-fold. In mouse skin wound infection models, Sb-doped VPNS (VPSb) achieves remarkable therapeutic efficacy against Staphylococcus aureus (S. aureus) infection and accelerates wound healing at a low concentration of 0.1 mg/mL. The optimized VPSb, with its excellent therapeutic performance, demonstrates great application prospects for clinical bacterial wound infection therapy.