A micro-concentrator photovoltaic module incorporating a bifacial silicon solar cell for direct and diffuse light capture

In this paper, we report findings from a micro CPV module, employing 170 μm GaAs-based 2J CPV cells, assembled on glass substrates using micro-transfer printing. The CPV array uses all-glass lens arrays to focus the light with a geometric concentration ratio of 740 suns, and a bifacial, monocrystalline silicon solar cell behind the substrate to capture the diffuse component of the light. We found that the diffuse capture creates a significant performance boost over CPV alone, and study the role of bifacial capture on the overall performance. The highest combined efficiency with respect to global normal irradiance was 25.4% for the module, measured by outdoor testing in Washington, DC.