Excitons and energy transport in crystals KPb2Cl5 and RbPb2Br5

A complex investigation of the dynamics of electronic excitations and energy transport in the KPb2Cl5 (KPC) and RbPb2Br5 (RPB) crystals was performed by means of low-temperature time-resolved vacuum ultraviolet optical luminescence spectroscopy with time resolution under selective excitation with synchrotron radiation. Data on the kinetics of the photoluminescence (PL) decay, time-resolved PL spectra (2-6.2 eV), and time-resolved PL excitation spectra (4-24 eV) at 7-300 K were obtained for the first time. The intrinsic PL bands at 2.4 (KPC) and 2.05 eV (RPB) were attributed to the radiative annihilation of the triplet excitons. This rare-earth (Pr, Er, Nd, Ho) doped crystals exhibit the characteristic luminescence of the appropriate activators. This paper discusses the electronic excitation dynamics and energy transport in these crystals.