Luminescence of PbxCa1-xMoO4 solid solutions

Abstract

Spectra of photoluminescence (PL) and X-ray excited luminescence (XRL) in region of 1.5-3.5 eV, PL excitation spectra (2.8 – 5.8 eV), thermally stimulated luminescence (TSL) and temperature dependence of luminescence output of both XRL and PL were measured for PbxCa1-xMoO4 solid solutions. XRL and PL spectra were studied at room temperature and T= 90 K for all x values. PL, XRL spectra contain one broad emission band (FWHM = 0.6 eV, Stokes shift from 1.2 to 1.9 eV) with the maximum in the region of 2.25 - 2.5 eV, whose maximum position nonlinearly depends on x parameter. This emission band effectively excited strictly in region of the fundamental absorption edge. PL and XRL output strongly depend on temperature and increases by dozens of times when cooling to Т = 90 K. The activation energy of quenching also nonlinear depend on x parameter. This emission band represents the intrinsic emission which arises due to the radiative annihilation of excitons self-trapped at the (MoO4)2− complexes - STE luminescence.