Chemical Synthesis of Organo-siloxene 2D Materials from Calcium Di-Silicide: Characterization, Dielectric and Electrochemical Studies

Silicon is one of the most used materials in semiconductors and electronic devices. Its miniaturization in two-dimensional (2D) scale is now a great challenge to improve and/or extend its application in many practical fields. Layered siloxene nanosheet (SiNS), a derived 2D silicon material with -H and -OH functional groups synthesized from calcium di-silicide (CaSi2) have attracted a great interest while its functionalization has been barely explored. Herein, the strategy of direct exfoliation of CaSi2 by thermal heating with benzyl groups was explored, leading to air stable functionalized silicon nanosheets. The obtained dispersible thin materials were found to be mostly Kautsky-type crystalline siloxene nanosheets that are arbitrarily terminated with benzyl, hydrogen and hydroxyl groups. Moreover, the dielectric study with temperature dependency showed high dielectric permittivities, without any conducting polymer, induced by different phenomena occurring on the layered nanosheets. Electrochemical studies displayed a diffusion-controlled process involving a fast electron transfer with the functionalized silicon-based materials as working electrodes deposited on carbon graphite electrode (CGE) in the presence of ferricyanide ions. Organo-modified siloxene are therefore potential electrode materials for electrochemical detection.