Time-resolved luminescence of nanocrystalline inorganic complex oxides

Abstract

Two types of complex nanosized oxides - cerium doped Y3Al 5O12 (YAG) and CaWO4- have been studied by means of time-resolved luminescence spectroscopy. Comparative study of time-resolve luminescence characteristics of cerium doped YAG single crystal, nanopowders and nanoceramic as well as for CaWO4 macro- and nanocrystals has been done. Two components in the decay kinetic of Ce 3+ related emission in YAG nanocrystals were detected and it was suggested that a different energy transfer rate to volume and surface Ce 3+ ions takes place. It is shown that the segregation of Ce 3+ ions near nanoparticles surface and/or dislocation lines plays a crucial role in degradation of light yield of cerium related luminescence in YAG nanocrystals. Time-resolved properties of sol-gel synthesized CaWO4 nanocrystals depends strongly on the synthesis rout. It was shown that shallow traps have a strong influence on the luminescence decay times of nanosized CaWO4. © 2007 IOP Publishing Ltd.