Luminescent Silicon Nanoparticles Capped by Conductive Polyaniline through the Self-Assembly Method

Graft polymerization has been used, for the first time, to prepare a dense conductive polymer coating on free-standing luminescent silicon nanoparticles. The silicon nanoparticles maintained their photoluminescence and crystallinity after surface modification. The nanoparticles were first surface hydroxylated and then reacted with (3-bromopropyl)trichlorosilane to form a dense bromopropylsilane monolayer. This was further reacted with aniline, which displaced the bromine atoms. The surface-bound aniline molecules were then used as active sites for the graft polymerization of polyaniline (PANI). The composition, structure, morphology, and other physical properties of the PANI-capped Si nanoparticles were examined by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy. The silane self-assembled monolayer effectively protected the silicon particles against photoluminescence quenching and degradation in basic solutions that rapidly...