Optical properties of SnO2 nanoparticles

In recent times, considerable research efforts have been focused on the exploration of novel optical properties of nanocrystalline SnO2 particles such as photoluminescence (PL). In the present work, spherical SnO2 nanoparticles are synthesized by solid state reaction at different temperatures using tin chloride dihydrate and sodium hydroxide flakes as precursors. Transmission electron micrograph shows uniform and spherical SnO2 nanoparticles of diameter 30-40 nm. Micro-Raman spectra show an inverse relationship of line-width with SnO2 particle size. The band gap of SnO2 is calculated by plotting (alpha h nu)(2) vs. h nu and extrapolating the linear portion of it to alpha = 0 and found it to be 3.76-4.24 eV. Photoluminescence intensity increases with the increase of solid state reaction temperature up to 873 K. This is attributed to the generation of the oxygen ion vacancies in SnO2.