Effect of 130 keV pulsed electron irradiation on the efficiency of radiative transitions in Eu-doped glass-ceramics CaSiO3

Abstract Polycrystalline glass-ceramic CaSiO3 doped with Eu3+ ions was obtained by devitrification. The analysis of the photoluminescent characteristics of the obtained glass-ceramic is carried out. It was found that as a result of the devitrification of CaSiO3, two phases are formed, identified as pseudowollastonite (β-CaSiO3) as the dominant phase together with a small percentage of tridymite (SiO2). The UV–Vis optical absorption of Eu3+-doped CaSiO3 was performed using a UV–Vis spectrophotometer. The main objective of this work was to study the effect of the pulsed corpuscular action of electrons accelerated in a field of 130 keV on energy transitions in the Eu3+ ion. It is found that, upon steady-state excitation of the photoluminescent signal in the PLE spectra of unirradiated samples at wavelengths below 300 nm, two broad excitation peaks are displayed, possibly associated with O − Eu and O − Si CT transitions. Above 300 nm the characteristic excitation band from 7F0 ground state to 5Hj, 5D4, 5Gj, 5L6, 5D3, and 5D2 states of the Eu3+ ions are shown. It was found that, as a result of exposure to an electron beam in the photoluminescence spectra of europium, a redistribution of the relative intensities of the 5D0 → 7F2 and 5D0 → 7F1 transitions occurs. The calculation of the asymmetry ratio of these transitions showed values for an unirradiated sample R21 = 2.06 and irradiated R21 = 2.52, which indicates a decrease in the symmetry of the crystal field around Eu3+ ions after irradiation. Several reasons for the decrease in the relative intensity of the Eu3+ luminescence signal after electron irradiation, caused by the effect of electrization of the material, intrinsic defects of the matrix, and inhomogeneous phase composition, are discussed.