title: 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.
authors.forename: Qingyu
authors.initials: Q
authors.lastname: Meng
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Dai
authors.forename: Wenjun
authors.initials: W
authors.lastname: Sun
authors.forename: Changwen
authors.initials: C
authors.lastname: Wang