Reversible Photobleaching of Silver Clusters in Silica-Based Glass under Ultraviolet Irradiation

Inorganic glasses doped with luminescent silver clusters are promising materials for photonic applications as white light generation, optical data storage, and spectral conversion. This work reports the photostability study of luminescent silver clusters dispersed in silica-based glass under continuous ultraviolet irradiation. The photobleaching process model is proposed and the quantum yield of photobleaching is derived from the experimental data. The proposed mechanism of photobleaching is photoionization of silver clusters. Degradation of cluster luminescence is reversible and restores after the heat treatment, indicating the possibility to release trapped electrons and return the initial charge state of clusters. The effect of heat treatment temperature on the luminescence restoration is studied, the amount of restored luminescent clusters depends linearly on the heat treatment temperature.