A micro-concentrator photovoltaic module incorporating a bifacial silicon solar cell for direct and diffuse light capture
Matthew P Lumb1, Kenneth J Schmieder2, Thomas C Mood3, Mitchell F Bennett1, Anmol Taploo1, James E Moore1, David Scheiman2, Eric Armour4, Brent Fisher5, Matt Meitl5, Jim Carter5, Miroslav Samarskiy5, Scott Burroughs5
1The George Washington University, Washington, DC, United States
/2US Naval Research Laboratory, Washington, DC, United States
/3Private Consultant, Alexandria, VA, United States
/4Veeco, Somerset, NJ, United States
/5Formerly of Semprius, Durham, NC, United States

In this paper, we report findings from a micro CPV module, employing 170 μm GaAs-based 2J CPV cells, assembled on glass substrates using microtransfer printing. The CPV array uses all-glass lens arrays to focus the light with a geometric concentration ratio of 740 suns, and a bifacial, mono-crystalline 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.