Organic–Inorganic Interfacial Dipole Induced by Energy Level Alignment for Efficient Photocatalytic Sterilization

Photocatalytic molecules are considered to be one of the most promising substitutions of antibiotics against multidrug-resistant bacterial infections. However, the strong excitonic effect greatly restricts their efficiency in antibacterial performance. Inspired by the interfacial dipole effect, a Ti 3 C 2 MXene modified photocatalytic molecule (MTTTPyB) is designed and synthesized to enhance the yield of photogenerated carriers under light irradiation. The alignment of the energy level between Ti 3 C 2 and MTTTPyB results in the formation of an interfacial dipole, which can provide an impetus for the separation of carriers. Under the role of a dipole electric field, these photogenerated electrons can rapidly migrate to the side of Ti 3 C 2 for improving the separation efficiency of photogenerated electrons and holes. Thus, more electrons can be utilized to produce reactive oxygen species (ROS) under light irradiation. As a result, over 97.04% killing efficiency can be reached for Staphylococcus aureus ( S. aureus ) when the concentration of MTTTPyB/Ti 3 C 2 was 50 ppm under 660 nm irradiation for 15 min. A microneedle (MN) patch made from MTTTPyB/Ti 3 C 2 was used to treat the subcutaneous bacterial infection. This design of an organic–inorganic interface provides an effective method to minimize the excitonic effect of molecules, further expanding the platform of inorganic/organic hybrid materials for efficient phototherapy.