Enhanced conversion efficiency of Yb2＋-Yb3＋-codoped glass as spectral converter for photovoltaic application

We propose a kind of Yb2＋-Yb3＋-codoped glass, which is used as spectral converter layer to adjust AM1.5 solar spectrum for a better match with silicon bandgap. The energy-level rate equations and power transmission equations are established to analyze the down-conversional effect of the codoped glass on solar spectrum. The numerical results show that with proper doping concentration and thickness the glass layer may improve conversion efficiency by about 12 %. Moreover, we also apply the modified spectrum as excitation source of solar cell in a simulation platform, and reveal that there is about 15 % improvement in practical cells.