Abstract

The effect of two distinct crystallographic sites on the optical properties and energy transfer process between Eu 3+ ions in a Y 2 O 3 lattice has been a recent focus of research in our laboratory. The luminescence and site selective emission resulting from the direct excitation of the 5 D 0 [arrow right] 7 F 0 level of C 2 and the 5 D 0 [arrow right] 7 F 1a level of C 3i sites at 580.0 and 582.2 nm respectively for Eu 3+ doped Y 2 O 3 nanocrystalline and bulk samples are reported in this thesis. It was observed for the 1mol% nanocrystalline and bulk samples that a two-way energy transfer process becomes possible over a 90cm -1 energy gap between the 5 D 0 levels of the distinct sites through thermal bridging at room temperature. Furthermore, the investigation of the lifetime of the 5 D 0 [arrow right] 7 F 2 (C 2 ) level for the nanocrystalline and bulk samples confirmed the two-way energy transfer process between Eu 3+ (C 3i )[Lef-right arrow]Eu 3+ (C 2 ) ions since the lifetimes obtained for 5 D 0 [arrow right] 7 F 2 level lengthened upon C 3i excitation both at 298K and 77K.