The spectral properties of different structural centers in nanocrystalline Gd2O3:Eu3+

Monoclinic and cubic Gd2O3:Eu3+ were prepared by combustion synthesis. The optical and structural properties have been investigated using photoluminescence (PL), photoluminescence excitation (PLE), site-selective excitation (SSE) spectra as well as fluorescence lifetime measurement. Three nonequivalent Cs centers in monoclinic phase and C2 center in cubic phase are distinguished. The energy transfers between three different Cs centers in monoclinic phase of nano-material were observed. The lifetime of 5D0 of Eu3+ in the nano-material is longer than that in bulk lattice, due to the effective refractive index decreasing.