Spectra of Some Rare Earth Vanadates

Spectra of some rare earth activated phosphors, where may be Y, Gd, or La, are presented. The most efficient phosphors, particularly in the matrix, are those activated by Sm +3 , Eu +3 , and Dy +3 . It is shown that has an output efficiency comparable to commercial phosphors. , when properly prepared, has an output intensity exceeding that of . The major energy absorption mechanism involves a charge transfer transition within the vanadate matrix from which energy is transferred via an exchange coupling mechanism resulting in excitation of the rare earth centers and subsequent emission of characteristic radiation.