Characterization of nano-size YVO4:Eu and (Y,Gd)VO4:Eu phosphors by low voltage cathodo- and photoluminescence

Low voltage cathodoluminescence (LVCL) and photoluminescence measurement were carried out to better understand the role of Gd in (Y,Gd)VO4:Eu phosphor and to compare two different synthesis methods (solid-state reaction, coprecipitation reaction) and their preparing conditions. From the analysis of LVCL measurement, it is understood that the luminescence of YVO4:Eu and (Y,Gd)VO4:Eu phosphors might be interpreted as originating from a two-level system and for reasons of enhanced luminescence intensity of (Y,Gd)VO4:Eu phosphor, the effect of Gd on the symmetry of Eu sites dominates over that of interaction between Gd and Eu. It is also found that nano-size phosphor of YVO4:Eu synthesized by coprecipitation reaction shows lower quantum yield in comparison with that synthesized by solid-state reaction due to the presence of secondary phase produced after heat treatment.