Principle of vanadium doping-induced MoS2 homojunction effect and mechanism analysis of antibacterial process under near-infrared light

MoS₂ exhibits unique physical and chemical properties in its 1 T and 2H phases. Each phase has its inherent advantages and limitations. Although several biochemical properties of MoS₂ have been extensively reported, the specific impacts of these phases on photothermal and antibacterial performance, the feasibility of integrating the unique advantages of both phases and the underlying dominant bactericidal mechanisms are still largely unexplored. In this work, the electronic-structural relationships of 1 T- and 2H-MoS₂ were first simulated using density functional theory (DFT), which provided unique insights into how these phases affect performance. Based on these insights, a solid-state coupling interface and built-in electric field were designed between the two phases, and a 1 T/2H MoS₂ homojunction was synthesized using the hydrothermal method, achieving a higher carrier separation efficiency and exhibiting excellent photothermal and antibacterial properties. Subsequently, further attempts were made to adjust the electronic structure by doping vanadium atoms. This doping not only introduces additional electrons to facilitate electron transfer but also further enhances the antibacterial capability by creating surface defects that increase the number of active sites. Finally, the synergistic antibacterial mechanism of this system was thoroughly investigated through detailed experiments and DFT theoretical analysis. The design of the homojunction, the introduction of defects, and the incorporation of heteroatoms were discussed in this paper, which pave the way for the rational design strategy of advanced two-dimensional materials and can be extended to other polycrystalline materials.