Mutual Effects of Fluorine Dopant and Oxygen Vacancies on Structural and Luminescence Characteristics of F Doped SnO2 Nanoparticles

SnO2 and F doped SnO2 (FTO) nanoparticles (NPs) have been synthesized by the hydrothermal method with subsequent annealing at 500 degrees C. The microstructure and photoluminescence (PL) property of SnO2 and FTO NPs have been investigated, and an assumption model about the luminescence process of FTO NPs has been proposed. All of the SnO2 and FTO NPs possess polycrystalline tetragonal rutile structures, and the average size in the range of 16.5-20.2 nm decreases with the increasing of F doping content. The doping element F is shown a uniformly distribution by electron energy loss spectroscopy (EELS) mapping. The oxygen vacancy concentration becomes higher as is verified by Raman and X-ray photoelectron spectra (XPS). There are three kinds of oxygen chemical states in SnO2 and FTO NPs, in which O corresponds to oxygen vacancies. The room temperature PL position is observed to be independent of F doping content. F- may substitute O2- into the SnO2 lattice by generating to ensure charge balance.