Spectral Characteristics and Thermal Quenching of Luminescence in Rb0.993Pr0.007Pb2Br5 and Rb0.993Pr0.007Pb2Cl2.5Br2.5 Crystals

Abstract

Crystals with the compositions Rb_0.993Pr_0.007Pb₂Br₅ and Rb_0.993Pr_0.007Pb₂Cl_2.5Br_2.5 have been grown by the Bridgman method, and the absorption, luminescence excitation, and photoluminescence spectra of these materials in the case of the Stokes mechanism of optical excitation in the blue spectral region have been analyzed. The intensity of the visible luminescence bands of the Pr³⁺ praseodymium ions has been shown to depend on the nature of the nearest neighbor atoms in their crystalline environment. This effect is tentatively attributed to changes in the probability of radiative transitions in the rare-earth ion. The temperature dependences of emission intensity obtained for the crystals demonstrate that the contributions of nonradiative recombination channels depend on the transition, which also leads to changes in the emission color of the compounds.