Monolithic hybrid tandem solar cells comprising copper indium gallium diselenide and organic subcells

Combining wide and narrow band gap absorbers in tandem solar cells is a promising approach to improve the energy conversion of sun light. In this work, we present hybrid tandem devices comprising monolithically connected copper indium gallium diselenide (CIGS) bottom cells and polymer top cells. The thin polymer:fullerene bulk heterojunction absorber layers were transferred onto the rough CIGS surface by a soft-contact lamination technique. Sputtered or solution-deposited top cathodes complete the tandem devices with enhanced open circuit voltages.