Temperature-Dependent Emission of Pr3+ -Doped LaB3O6 under Vacuum Ultraviolet Excitation

The vacuum ultraviolet (VUV) luminescent properties of Pr3+ -activated LaB3O6 were investigated with high-energetic synchrotron radiation from 20 to 300 K. In the emission spectra, the parity-forbidden 4f2→4f2 and parity-allowed 4f5d→4f2 transitions were observed simultaneously. In addition, it was also observed that the intensity of 4f5d→4f2 emission bands increased relative to the intensity of 4f2→4f2 emissions with increasing temperature. The thermal equilibrium model of energy levels was employed with respect to the lowest 4f5d state and 1S0 state of LaB3O6: Pr3+, as a result of which the fitted curve had a good agreement with the experiment values, which clarified the physical nature of temperature-dependent emission characteristics of Pr3+ in LaB3O6.