Study on UV excitation properties of Eu3+ at S6 site in bulk and nanocrystalline cubic Y2O3

Increases of emission intensities for Eu3+ at the S-6 site relative to that at the C-2 site were observed as UV excitation wavelength decreases from 300 nm to 200 nm in both bulk and nanocrystalline cable Y2O3 : Eu3+. Decomposition of excitation spectra shows that the charge transfer band of Eu3+ at the S-6 site lies in the high-energy side of that at the C-2 site, resulting In that the energy transfer from the host prefers to the S-6 site. Detailed emission and excitation spectral characteristics were analyzed and discussed. In addition, spectral red-shift were found in both charge transfer bands in nanocrystalline Y2O3 : Eu3+ compared to the bulk material. The number ratio of S-6 sites to C-2 sites is also smaller in nanocrystalline Y2O3 : Eu3+ than that in the bulk one.