Optimization of thin film coatings for textured silicon solar cell above low band gap solar cell

As crystalline silicon solar cells may be approaching efficiency limits, a promising approach to further efficiency gains is a stacked, tandem system consisting of silicon and below silicon band gap cells capable of utilizing a larger range of the solar spectrum. In this work, we analyze a textured silicon cell with coatings optimized to transmit below band gap photons. For the first time, our model takes into account multiple reflections in such a transparent but light trapping cell. We find an efficiency of 26.5% is attainable, for an absolute efficiency gain of 1.3% over a standalone, light trapped silicon cell.