Contrasting emission behaviors of YAG:V5+ co-doped with Pr3+or Eu3+

The emission spectra of Y3Al5O12:V5+ (YAG:V) under excitation into the VO43- absorption bands give in addition to the broad vanadate emission, sharp bands from unintentional trace amounts (∼1 ppb) of Eu3+ impurity, which are similar to the emission of YVO4:Eu3+, but different from YAG:Eu3+. At much higher Eu3+ concentrations, for YAG:V:Eu3+, the YAG:Eu3+ or YVO4:Eu3+ emissions can be selectively excited. By contrast, the emission of Pr3+ in YAG:V,Pr3+ is the same as that of YAG:Pr3+ (and not YVO4:Pr3+) but it is weaker on exciting into the intense VO43- absorption band. The YVO4:Pr3+ emission from the 3P0 state is absent due to intervalence charge transfer.

Trace Eu3+ impurity present in YAG:V5+ gives YVO4:Eu3+ and not YAG:Eu3+ emission, whereas Pr3+ emission in YAG:V5+ is the same as for YAG:Pr3+.