Irradiation effect on luminescence properties of fluoroperovskite single crystal (LiBaF3:Eu2+)

Single crystals of pure and Eu2+ doped LiBaF3 have been grown from melt by using a vertical Bridgman-Stockbarger method. Effects induced by irradiation on europium doped LiBaF3 (lithium barium fluoride) single crystals were monitored by optical absorption, photoluminescence and thermoluminescence studies. The absorption bands of Eu2+ ions with peaks at 240, 290 and 320 nm were observed in the LiBaF3:Eu2+ crystal. Drastic increase in absorption was noted below 600 nm after gamma irradiation, which was dependent on the radiation dose. The additional absorption peak at around 570 nm was observed in irradiated crystal due to the ionization process Eu2+(-)e(-) -> Eu3+. Photoluminescence of Eu2+ doped LiBaF3 single crystal shows sharp line peaked at similar to 359 nm and a broad band extending between 370 and 450 nm which shows a considerable reduction in Eu2+ PL intensity after gamma irradiation. Irradiated LiBaF3:Eu2+ sample has revealed three intense TL glow peaks at 128 degrees C (peak-1), 281 degrees C (peak-2) and 407 degrees C (peak-3). Activation energy (E) and frequency factor (s) of the latter two peaks were determined by various heating rate (VHR) method and graphical method. (C) 2013 Elsevier Ltd. All rights reserved.