Direct Chemical Synthesis of Benzyl-Modified Silicane from Calcium Disilicide

Chemically functionalized two-dimensional silicon materials, which are known as silicanes, have recently attracted attention because of their unique physical and chemical properties. Here, we report a simple and efficient synthesis of benzyl-modified silicane (BnSi) involving the reaction of calcium disilicide (CaSi2) with benzyl bromide (BnBr) using a closed reactor system made of Teflon. The nucleophilic reaction between CaSi2 and BnBr proceeds at 150 °C without a solvent, and BnSi, in which Bn groups are bonded to the Si framework via Si–C bonds, is generated in a yield of 27.4%. Moreover, the densely introduced Bn groups lead to a reduction in band gap, resulting in visible light absorption by BnSi. As a result, BnSi loaded on a transparent conductive electrode generates photocurrent under visible light irradiation at a suitable applied potential.