Preparation of a novel fluorosilicate salt for electrodeposition of silicon at low temperature

A novel fluorosilicate salt, 1-ethyl-3-methylimidazolium hexafluorosilicate ((EMI)(2)SiF6), was prepared by the reaction of EMICI and hexafluorosilicate acid aqueous solution. A transparent thin film containing silicon was deposited on a silver electrode by potentiostatic electrolysis in molten (EMI)(2)SiF6 at 90 degreesC. The film was reactive against water to form silicon dioxide. (EMi)(2)SiF6 was found to dissolve in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfone)imide (EMITFSI) room temperature molten salt. The same thin film was also obtained on a silver electrode by potentiostatic electrolysis in EMITFSI containing (EMI)(2)SiF6 at room temperature.