Carrier multiplication (CM) is a promising approach to surpass the Shockley-Queisser limit in single-junction photovoltaic cells. While halide perovskites show strong CM effects spectroscopically, their impact on perovskite solar cells (PSCs) remains unclear. This study investigates CM in Cs0.05FA0.5MA0.45Pb0.5Sn0.5I3 PSCs. The material exhibits efficient CM with a low threshold of 2Eg (~500 nm) and high efficiency (99.4 ± 0.4%). An unbiased internal quantum efficiency exceeding 110% (reaching 160% in the best devices) is achieved due to robust CM. The research analyzes the interplay of factors affecting CM's contribution to overall performance (optical and parasitic absorption losses, charge recombination and extraction). Surprisingly, CM effects are found to exist in mixed Pb-Sn PSCs but are suppressed by the current device architecture. A significant device redesign is proposed to harness CM for next-generation PSCs.

Yue Wang, Senyun Ye, Jia Wei Melvin Lim, David Giovanni, Minjun Feng, Jianhui Fu, Harish N S Krishnamoorthy, Qiannan Zhang, Qiang Xu, Rui Cai, Tze Chien Sum