The Size Confinement Effect for Eu3+ Concentration Quenching and Energy Transfer in YVO4 Nanocrystal

Abstract

YVO4:Eu3+ nanocrystal powders (∼30 nm) with different doping concentrations were prepared using a precipitation method. Bulky powders (∼500 nm) were obtained by annealing the nanopowders at high temperature. The concentration quenching of luminescent centers and energy transfer in YVO4: Eu3+ powders were investigated. It was found that quenching concentration for Eu3+ 5D0→7F2 transition emission in nanopowders is distinctly higher than that in bulk powders. The type of energy transfer that caused concentration quenching was identified to be electric dipole–dipole interaction in bulk powders and exchange interaction in nanopowders. The electric dipole–dipole interaction is a long-range interaction (operating range of several nanometers). The size confinement effect of boundary in nanoparticles has obvious inhibitory effect on electric dipole–dipole interaction, and hardly affect the exchange interaction which is a short-range interaction (operating range several angstroms). The electric dipole–dipole interaction is restrained by particle boundary in nanopowders. So energy transfer of Eu3+ ions in nanomaterials is dominated by exchange interaction, and quenching concentration of nanomaterials is higher than in bulky materials.