Quantum efficiency and surface passivation effect of nanocrystalline Y2O3:Eu3+

Cubic nano-crystalline Y2O3:Eu3+ powders with different grain sizes were produced by chemical auto-combustion, and their structure, morphology, and fluorescent spectra were characterized. The quantum efficiency of the 5D0 level of Eu3+ was estimated, taking into account the energy transfer between Eu3+ ions located at C2 and S6 sites. Ag+ ions were introduced into the synthesis of the nanosized particles to modify the surface defects, resulting in increased emission intensity. These results indicated that the nanosized Y2O3:Eu3+ exhibits maximum internal quantum efficiency close to 90% after Ag+ ions are introduced into the synthesis of Y2O3:Eu3+. From the experimental results, it was concluded that the Ag+ ions are probably absorbed by the nanoparticle surface and do not enter the nanoparticle lattice. It was also found that the Ag+ ions can repair the surface defects and make the absorption of excitation light more efficient.