Crystallinity control of flame generated composite nanoparticles by laser irradiation

Abstract

Abstract Continuous wave CO 2 laser was irradiated on SiO 2 /TiO 2 composite nanoparticles generating in a flame to in-situ control the crystalline phase. The laser irradiation was not only shown to transform originally amorphous composite nanoparticles into the crystalline ones, but also to control the crystallite size of TiO 2 embedded in SiO 2 nanoparticles by altering the irradiating laser power. X-ray diffraction analysis and transmission electron microscope analysis confirmed that the size of TiO 2 anatase crystallites in silica nanoparticle increased with increasing the irradiation laser power. It was shown that the corresponding absorption edge of SiO 2 /TiO 2 composite nanoparticles could be controlled by changing the crystallite size of TiO 2 inside SiO 2 nanoparticles.