Local structure and luminescence of nanocrystalline Y2O3:Eu

Nanosized ${\mathrm{Y}}_2{\mathrm{O}}_3:\mathrm{Eu}$ was synthesized by using a solution–combustion method. The samples were characterized by x-ray diffraction, extended x-ray absorption fine structure (EXAFS), and photoluminescence spectroscopy. Our EXAFS result showed that the local environments surrounding both Y and Eu atoms had obviously changed when the particle size was smaller than 10 nm. The coordination number and the bond length of Y (Eu)–O shell increased and the disorder became larger. This change also produced an emission peak and the charge-transfer band showed an unusual redshift as the particle size decreased. The luminescence properties can be explained by use of the EXAFS results.