Solution-Processable Two-Dimensional In₂ Se₃ Nanosheets as Efficient Photothermal Agents for Elimination of Bacteria

Two-dimensional (2D) nanoflakes represent an appealing class of materials for optoelectronics applications due to their unique layered structures and excellent electronic properties. However, the lack of easy-to-manipulate and effective methods for large-scale production of these 2D materials limits their potential for applications. Also, few efforts have been made to explore their applications in biological fields. This work reports the preparation of large quantities of 2D In₂ Se₃ nanosheets through a solvent exfoliation technique. Transmission electron microscopy and atomic force microscopy results show that the In₂ Se₃ nanosheets are obtained with lateral sizes of tens of nanometers to hundreds of nanometers and thickness of 2-17 layers. Raman features coupled with the X-ray diffractometry results unequivocally confirm the as-prepared In₂ Se₃ nanosheets to be α phase. Moreover, these α-In₂ Se₃ nanosheets exhibit an excellent near-infrared (NIR) photothermal performance under an 808 nm laser irradiation. NIR photo-excitation of the α-In₂ Se₃ nanosheets in the presence of bacteria leads to a significant antibacterial effect, suggesting that these nanosheets have great potential to be photothermal antibacterial agents. Our work on α-In₂ Se₃ nanosheets presents an available method for exfoliating 2D layered materials, and highlights the potential application in chemical and biological fields of α-In₂ Se₃ nanosheets.