Temperature dependence of the defect luminescence in La2Be2O5 single crystals

• We studied La2Be2O5 (BLO) single crystals (pristine and RE3+-doped).
• We studied PL emission spectra of defects in BLO and BLO:RE3+.
• Temperature quenching of the defect PL emission was studied at 80–500 K.
• We developed the reaction rate model to describe non-monotonic TQ-curves.
• TQ-curves were parameterized for BLO, BLO:RE3+ (RE = Ce, Pr, Eu, Nd, Er).

Temperature quenching (TQ) curves in the temperature range of 80–500 K have been studied for both the undoped, and doped with RE3+-ions (RE = Ce, Eu, Er, Pr, Nd) lanthanum beryllate (BLO) single crystals. Photoluminescence spectra and TQ-curves were recorded upon excitation in the absorption bands of the lattice defects. The reaction rate model has been developed to describe the experimental results. The model includes two competing processes with characteristic temperatures: thermal quenching of intracenter PL (T1) and thermally stimulated migration of electronic excitations (T2). The competition between these two processes leads to the observed non-monotonic TQ-curves. The rationalized formulas using three parameters (intensity, activation energy, characteristic temperature), were developed to describe each of these processes. Within the framework of the unified model, all the experimental results were described and the best fit parameters were obtained. Classification of the investigated lanthanum beryllate crystals was carried out in line with the best fit parameters obtained for the TQ-curves.