Near‐Infrared Light Responsive S‐Scheme Bi ₂ S ₃ @Ag ₂ S Heterojunction for Synergistic Photothermal and Photodynamic Antibacterial

Abstract Bacterial infections seriously threaten human health, while drug resistance makes the development of efficient antibacterial agents highly challenging. Near‐infrared (NIR) light‐triggered photothermal therapy (PTT) and photodynamic therapy (PDT) have recently emerged as promising alternatives for antibacterial treatment, and constructing heterojunctions provides an effective strategy to enhance their antibacterial efficiency. Here, a NIR responsive novel S‐scheme heterojunction of Bi 2 S 3 @Ag 2 S with outstanding photothermal conversion efficiency (46.3%) and promoting the generation of reactive oxygen species (ROS) is constructed. The enhanced PDT is confirmed through the efficient degradation of antibiotic tetracycline hydrochloride and the generation of superoxide radicals (∙O 2 − ) and singlet oxygen ( 1 O 2 ) due to the enhanced separation efficiency of photogenerated carriers. Furthermore, the feasibility of Bi 2 S 3 @Ag 2 S as an antibacterial agent is evaluated through in vitro experiments against Escherichia coli and Staphylococcus aureus , in which bactericidal rates achieve of 97.2% and 96.1%, respectively. These results highlight the Bi 2 S 3 @Ag 2 S heterojunction as a promising multifunctional platform that integrates efficient photothermal and photodynamic therapy with simultaneous antibiotic removal, offering broad prospects for biomedical and environmental applications.