Eu3+ ion as fluorescent probe for detecting the surface effect in nanocrystals

Nanocrystalline yttrium vanadate doped with trivalent europium ions, YVO4:Eu3+, was synthesized via the microemulsion mediated hydrothermal process. Laser selective excitation spectra were employed to probe the local environments of Eu3+ ions in YVO4 nanocrystals. The local environments of the dopant ions were diversified because of the surface effect in nanocrystals, which led to an increase in linewidth in excitation and emission spectra. Furthermore, the change of site symmetry from the interior to the surface of nanoparticles was clearly exhibited in the emission spectra of Eu3+ ions under different excitation wavelengths. The results show that the fluorescent behavior of doped Eu3+ ions may be a useful probe for detecting the surface effect in nanosize materials.