New two-dimensional functionalised silicon nanosheets prepared by direct exfoliation of calcium disilicide with tosyl chloride

Among the variety of two-dimensional (2D) materials, silicon nanosheets (SiNSs) having nanometres thicknesses and lateral dimensions ranging from the submicrometer to the micrometre scale are highly desired for practical applications in physic area. Chemical exfoliation of calcium disilicide (CaSi2) Zintl phase is the most common route to prepare crystalline functionalised silicon nanosheets. However, the chemical functionalization of such layered materials suffers some disadvantages and needs to be improved. Herein, the synthesis of a new-layered organosilicon material is described, namely tosyl-modified silicane (Si_Ts), by the direct exfoliation of CaSi2 with p-Toluenesulfonyl chloride (tosyl chloride: TsCl), in nitrogen gas at 110°C in a sand bath. The new crystalline silicon-based functionalised material was successfully characterised by different spectroscopic techniques, which confirmed the impregnation of the organic compound onto the surface of layered nanosheets. This method opens the access of a large-scale synthesis of new hybrid organosilicon 2D materials, which are suitable for optical, electric, or photovoltaic applications.