Spectral down-conversion in sm-doped borate glasses for photovoltaic applications

Samarium-doped borate glasses containing different types and concentrations of network modifiers are investigated as down-converting top glass for silicon solar cells. Optical and structural properties of the glasses are investigated by Fourier transform infrared spectroscopy, optical absorption and fluorescence spectroscopy. The outstanding characteristics are high optical transparency, robustness and price. Upon excitation above the ultraviolet (UV) absorption edge, borate glasses show a broad and intense fluorescence in the UV and blue spectral range. It is shown that borate glasses are good candidates as a matrix material for fluorescent ions like samarium.