A supramolecular approach to improve the performance and operational stability of all-perovskite tandem solar cells

Wide-bandgap perovskite is pivotal as a photoactive layer in the top cell of prevailing tandem solar cells. However, the intrinsic instability of wide-bandgap perovskite solar cells is predominantly attributed to the vacancy defects caused by multiple ion migration. Here, we incorporate an ether ring super-molecule into perovskite. This supramolecular approach effectively manipulates the crystallization kinetics and suppresses the halide segregation under illumination by tuning the coordination of halides toward monovalent cations and lead ions. As a result, the supramolecular engineered 1.77 eV perovskite solar cells achieve a champion power conversion efficiency of 21.01% with an outstanding operational stability, retaining 95% of initial efficiency after 1000 h σof maximum-power-point tracking test. Meanwhile, the two-terminal all-perovskite tandem solar cells achieve the champion efficiency of 28.44% (certified 27.92%). This work paves an avenue to improve the film quality and illumination stability of mixed halide wide-bandgap perovskites with a supramolecular approach.