A Generalized Analytic Model to Tailor Back Contact Design of Bifacial PERC-type Cu(In,Ga)Se 2 solar cells

Copper Indium Gallium Selenide (CIGS) has been widely used as a thin-film absorber material in photovoltaics (PV). Process improvements have pushed efficiencies to 22.8%, approaching the Shockley-Queisser limit. For further improvement, bifacial PV, which couples light into the absorber from both sides, has emerged as a promising approach. Here we present a generalized analytic model to design the back contact pattern of bifacial CIGS solar cells for maximum power output at any albedo. At the global average albedo of 30%, we find that additional 2.4 mW/cm2 can be obtained by switching from monofacial to bifacial PERC configuration. Our results serve as contact design guidelines for manufacturers, which can be used to forecast the potentials of bifacial CIGS through levelized cost of electricity (LCOE) calculations.