Improving Perovskite/CIGS Tandem Solar Cells for Higher Power Conversion Efficiency through Light Management and Bandgap Engineering

Perovskite and chalcopyrite materials are excellent absorbers for highly efficient, all-thin-film tandem solar cells. This work presents a certified world record for such a device, achieving a power conversion efficiency of 24.6 ± 1.1% under steady-state conditions. The best IV parameters extracted from certified current–voltage measurements presented a short-circuit current density of around 19.3 mA/cm 2 , an open-circuit voltage of 1.765 V, and a fill factor of 71.8%. In comparison to our previous record, the current density improved considerably, mainly due to the lowering of the bandgap of the bottom subcell and the improved optics of the top perovskite cell.