Study on UV excitation properties of y ₂O ₃=Ln ³⁺ (Ln = Eu ³⁺ or Tb ³⁺) luminescent nanomaterials

Y ₂O ₃:Ln ³⁺ (Ln = Eu or Tb) nanocrystals with different Ln ³⁺ doping concentrations and average sizes were prepared by chemical self-combustion. The corresponding bulk materials with various doping concentrations were obtained by annealing the nanomaterials at high temperature. The emission spectra, excitation spectra, and X-ray diffraction spectra were used in this study. It was found that the charge transfer band of Y ₂O ₃:Eu ³⁺ red-shifted as particle size decreased, and the charge transfer band in the 5-nm particles obviously broadened toward the long wavelength. It was also found that the profile of excitation spectra corresponding to the 4f5d (Af ⁸ → 4f ⁷5d ¹) transition changed a lot with the variation of the particle size. The dependence of the excitation spectra of Y ₂O ₃:Ln ³⁺ on particle size was investigated.