Luminescence concentration quenching of D-1(2) state in YPO4 : Pr3+

Under selective excitation of the P-3(0) level of the Pr3+ ion in YPO4, the emission spectra and fluorescence decay curves were measured at different concentrations and temperatures. The origin of the spectral line located at 16318 cm(-1) (612.8 nm) was discussed and attributed to the D-1(2) --> H-3 (4) transition. The process of concentration quenching for the D-1(2) state was also studied. Using the Inokuti-Hirayama model, the non-exponential fl uorescence decay curves of the D-1(2) level were fitted. The result shows t hat dipole-quadrupole interaction between Pr3+ ions, which causes D-1(2) -- > (1)G(4) and H-3(4) --> F-3(4) cross-relaxation, results in the quenching of D-1(2) emissions.