Laser-induced SnO2 crystallization and fluorescence properties in Eu3+-doped SnO2-SiO2 glasses -: art. no. 104204

SnO2 nanoparticles having an average particle size of 5 nm were precipitated in transparent glasses by irradiation with an 800-nm femtosecond laser pulse. Glasses, prepared to codope Sn4+ and Eu3+ ions by a sol-gel method, were heated in a H-2 gas atmosphere, in which the Sn ions are coordinated by two oxygen ions with point defect of a molecularlike electronic structure. Upon laser pulse irradiation, the twofold-coordinated Sn atoms are activated to react with oxygen, resulting in the formation of SnO2 nanocrystals. The precipitated SnO2 crystals grew up to circa 5-nm size by the Joule-heating effect of the laser. The fluorescence intensities of the codoped Eu3+ ions were enhanced higher than 100 times that of the glass without nanocrystals by exciting with an energy corresponding to the absorption edge of the SnO2 nanocrystals, the energy of which is effectively transferred to the Eu3+ ions. It was found that the Eu3+ ions are located in the glass structure from the fluorescence line narrowing spectroscopy.