Hierarchical nanofibrous silicon as replica of natural cellulose substance

Photo-luminescent nanofibrous crystalline silicon with hierarchical cross-linked network structures was obtained by low-temperature magnesiothermic reduction of nano-precise silica replica of natural cellulose substance (e.g., commercial filter paper and cotton). Ultrathin silica films were deposited onto the individual nanofibres of cellulose substance by surface sol-gel process, and successive calcination of the silica/cellulose composite gave nano-precise silica replica of the initial cellulose substance; further reduction of the silica matter at 670 degrees C resulted in bulk nanofibrous silicon material which was composed of crystalline silicon nanofibres replicated strictly from the original cellulose nanofibres. The resulting porous nanofibrous structured silicon material possesses strong blue or red photoluminescence when excited with ultraviolet or green light.