Radiophotoluminescence behavior in Ag-doped phosphate glasses

Radiophotoluminescence (RPL) is an emission phenomenon induced by the photoexcitation of luminescent centers (RPL centers) formed by ionizing radiation. Ag-doped phosphate glasses exhibiting RPL are applied in glass badge dosimeters used for personal monitoring. In this paper, we discuss the RPL behavior of Ag-doped phosphate glasses and their properties along with RPL center formation and disappearance mechanisms. When Ag-doped phosphate glasses are exposed to ionizing radiation, Ag-0, Ag2+, and Ag-m (n+), such as Ag-2 (+), clusters are formed because Ag+ acts as an electron and hole trap. Ag2+ is formed by the transfer of holes from PO4 (3-) tetrahedra. On the other hand, electrons are trapped by Ag+ to form Ag-0. Subsequently, Ag-2 (+) is formed by the association between Ag-0 and Ag+ owing to the diffusion of Ag+. Ag-0 is attributed to blue RPL center, while Ag2+ and Ag-2 (+) are attributed to orange RPL centers. Moreover, Ag-2 (+) and Ag2+ disappear upon heating at 500 and 673 K, respectively.