Intrinsic [VO4](3-) emission of cesium vanadate Cs5V3O10

摘要

Polycrystalline Cs5V3O10 micro-particles were synthesized by a solid-state reaction. The vanadate shows intrinsic self-activated luminescence of a single broad band with a peak at 520 nm, extending from about 400 nm to 720 nm. This asymmetric band is composed of two bands due to the electronic transitions from the T-3(1) and T-3(2) excited states to the (1)A(1) ground state in [VO4](3-) centers. The same emission band was obtained for micro- and nanoparticles. It is suggested that the broadening of the emission band arises from single [VO4](3-) molecules. The emission and decay curve profiles indicate that the emission is not due to different kinds of [VO4](3-) centers but only one kind of [VO4](3-) center. When the temperature is increased from 10 K to 450 K, the emission intensity increases below 150 K and decreases above 150 K, and an unusual blue shift is observed. The observed temperature dependence can be understood by the relaxation processes of the emitting T-3(1) and T-3(2) states including the thermal feeding by the lower-energy T-3(1) state to the higher-energy T-3(2) state.