Elucidation of electron and hole transfer at high temperature in Ag-doped Na and Al phosphate glasses

Abstract

Ag-doped phosphate glasses are used in radiophotoluminescence (RPL) dosimeters. Ag0, Ag2+ and Ag2 + act as luminescence centers of RPL in the glass, whereas they disappear when annealed. To understand the reason for the RPL disappearance phenomenon, thermoluminescence (TL) glow curves, RPL temperature dependence electron spin resonance spectra were measured for the self-made Na and Al phosphate glass (Na–Al) and Ag-doped Na–Al made by Chiyoda Technol (FD-7). It is shown conclusively that in FD-7, electrons trapped at Ag2 + recombine with a part of holes trapped at hole trapping sites other than PO4 3− tetrahedra at 350–400 K, while electrons trapped at Ag2 + recombine with holes trapped at Ag2+ at 400–500 K. Subsequently, holes trapped at Ag2+ recombine with electrons trapped at electron trapping sites other than Ag2 + to induce TL at 520–650 K.