Correlation between SnO2 nanocrystals and optical properties of Eu3+ ions in SiO2 matrix: Relation of crystallinity, composition, and photoluminescence

We report characteristics and optical properties of Eu3+-doped SnO2 nanocrystals dispersed in SiO2 matrix. Samples are prepared by the sol-gel method. Crystallinity of SnO2 nanocrystals is examined by X-ray diffraction experiments. At annealing temperatures from 900 to 1200 °C, we observe the formation of single tetragonal rutile structure of SnO2 nanocrystals. Average sizes of SnO2 nanocrystals within 3-7 nm are estimated by Debye-Scherrer equation. Intense photoluminescent spectra of Eu3+ ions consist of a series of resolved emission bands within 570-645 nm, which are varied with different sample-preparation conditions. We show the efficient excitation process of Eu3+ ions through SnO2 nanocrystals in the materials. Microscopic structure of SnO2 nanoparticles and optical properties of Eu3+ ions are also presented and discussed.