Fill Factor Losses and Deviations from the Superposition Principle in Lead Halide Perovskite Solar Cells

The enhancement of the fill factor in current generation perovskite solar cells is key for further efficiency improvement. Thus, methods to quantify losses are urgently needed. Two presented due finite resistance semiconducting layers cell as well its contacts. first method based on comparison between voltage dark and under illumination analyzed at equal recombination density results a voltage-dependent series resistance. Furthermore, reveals existence strong photoshunt illumination. second measuring photoluminescence function applied voltage. Thereby, determined from short circuit open circuit, presence explained with high electron and/or hole transport combined field screening absorber.