Influence of nanoenvironment on luminescence of Eu3+ activated SnO2 nanocrystals

The emission intensity of the peak at 612 nm (D-5(0) --> F-7(2)) of the Eu3+ ions activated SnO2 nanocrystals (doped and coated) is found to be sensitive to the nanoenvironment. We have compared the luminescence efficiencies of the nanocrystals of SnO2 doped by Eu2O3 with those of SnO2 coated by Eu2O3 and we found that the intensities are significantly higher in coated nanocrystals. Furthermore, it is clear from luminescence intensity measurements that Eu3+ ions occupy low symmetry sites in the Eu2O3 coated SnO2 nanocrystal. The analysis suggests that the radiative relaxation rate is higher in Eu2O3 coated SnO2 nanocrystals than Eu2O3 doped SnO2 nanocrystals due to the asymmetric environment of Eu3+ ions in coated samples. (C) 2004 Elsevier Ltd. All rights reserve