Ion exchange doping of solar cell coverglass for sunlight down-shifting

In this work, silicate glass slides were doped with silver or copper by ion exchange in molten salts in order to obtain luminescent sheets suitable as down-shifters to be used for covering and protecting solar cells. The samples were treated at different temperatures, in nitrate, sulfate and chloride salts, for different times. Post-exchange thermal treatments were performed on some of them in order to tailor the ion aggregation states and their luminescence features. Optical absorption and near ultraviolet–visible luminescence analyses were performed in order to test the suitability of the samples as down-shifters and,moreover,X-ray absorption near edge structure (XANES) analyses were performed on copper doped samples in order to better identify the oxidation states of the incoming ion as a function of the synthesis parameters. The performance of the best samples was tested by measuring the output power of a GaAs solar cell covered with the treated glass slides and illuminated with a solar simulator lamp.