Photoluminescence optimization of luminescent nanocomposites fabricated by spray pyrolysis of a colloid-solution precursor

Spherical Gd(2)O(3):Eu(3+)/silica luminescent nanocomposite particles have been synthesized by spray pyrolysis of the precursor with colloidal silica nanoparticles and gadolinium and europium nitrate solutions. The as-prepared particles were characterized using field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence (PL) spectra, as well as Fourier transform infrared spectroscopy. The results showed that the content of silica nanoparticles has a strong effect on the size, morphology, crystallinity, and PL properties of the composite particles. By adding colloidal silica nanoparticles into the precursors, dense luminescent particles with improved characteristics were produced because the silica nanoparticles as seeds promote heterogeneous nucleation during the pyrolysis of Gd(2)O(3):Eu(3+). The effect of the size of silica nanoparticles on the characteristics of the composites was investigated as well. The PL intensity and crystallinity increased with increasing silica nanoparticle size and reached optimum conditions using silica nanoparticles with an average size of 50 nm for a similar volume percentage of silica. In this case, the number and the surface area of silica nanoparticles play roles in determining the characteristics. (c) 2007 The Electrochemical Society.