Stability of sol-gel silica glass for CPV and Ultraviolet LED applications

This paper concerns the characterization of silica glass obtained by a sol-gel technique as to its suitability in the terrestrial and space concentrated photovoltaic (CPV), and ultraviolet light emitting diode (UV LED) industrial sectors. The sol-gel material tested is produced by Evonik Industries and marketed under the brand name SAVOSIL™. The tests performed were aimed at determining the endurance of the material to radiation exposure and consist of exposure to gamma radiation and 355 nm UV laser light. In these tests the transmittance of the glass was measured before and after the exposure to the radiation to determine the effect of the radiation treatment. In the case of the test with the 355 nm laser, in situ measurements were also performed during the irradiation treatment to check for any transitory effects of the high intensity radiation. As a reference and for comparison all the tests were also performed under the same conditions on samples of a commercial optical glass of the type commonly used for CPV applications.