50% Sn‐Based Planar Perovskite Solar Cell with Power Conversion Efficiency up to 13.6%

In the present work, a Pb‐assisted two step method is successfully proposed to fabricate high‐quality CH 3 NH 3 Sn 0.5 Pb 0.5 I 3 (MASn 0.5 Pb 0.5 I 3 ) perovskite film on the indium tin oxide (ITO) glass/poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) substrate. The film shows regular crystalline grains with a flat and compact morphology as well as full coverage on the planar PEDOT:PSS substrate. Remarkably, corresponding devices ITO/PEDOT:PSS/MASn 0.5 Pb 0.5 I 3 /C 60 /2,9‐dimethyl‐4,7‐diphenyl‐1,10‐phenanthroline/Ag are fabricated with high reproducibility, achieving a high power conversion efficiency of 13.6%, which is, to the best of knowledge, the most efficient solar cell based on Sn‐based perovskite.