Laser precipitation of SnO2 nanocrystals in glass and energy transferred-fluorescence of Eu3+ ions

SnO2 nanoparticles having an average particle size of 5 nm were precipitated in a transparent glass by irradiation with an 800 nm femtosecond laser. Glass was prepared to co-dope Sn4+ and Eu3+ ions by a sol–gel method, followed by heating in H2 gas atmosphere to form the Sn02 point defects with a molecular-like electronic structure in the twofold-coordinated Sn atoms. Upon laser irradiation, the Sn02 defects react with oxygen, forming SnO2 nanocrystals. When excited at the energy corresponding to the absorption edge of the SnO2 nanocrystals, the energies, which are absorbed by the quantum-dot effect in the nanosized crystals, are efficiently transferred to the Eu3+ ions, resulting in the large enhanced fluorescence intensities from the Eu3+ ions. The observed phenomenon suggests application to high-density memory devices.