Zhang, HongEickemeyer, Felix ThomasZhou, ZhiwenMladenović, MarkoJahanbakhshi, FarzanehMerten, LenaHinderhofer, AlexanderHope, Michael A.Ouellette, OlivierMishra, AdityaAhlawat, ParamvirRen, DanSu, Tzu-SenKrishna, AnuragWang, ZaiweiDong, ZhaowenGuo, JinmingZakeeruddin, Shaik M.Schreiber, FrankHagfeldt, AndersEmsley, LyndonRothlisberger, UrsulaMilić, Jovana V.Graetzel, Michael2021-06-072021-06-072021-06-072021-06-0710.1038/s41467-021-23566-2https://infoscience.epfl.ch/handle/20.500.14299/178701Formamidinium lead iodide perovskites are promising light-harvesting materials, yet stabilizing them under operating conditions without compromising optimal optoelectronic properties remains challenging. We report a multimodal host–guest complexation strategy to overcome this challenge using a crown ether, dibenzo-21-crown-7, which acts as a vehicle that assembles at the interface and delivers Cs+ ions into the interior while modulating the material. This provides a local gradient of doping at the nanoscale that assists in photoinduced charge separation while passivating surface and bulk defects, stabilizing the perovskite phase through a synergistic effect of the host, guest, and host–guest complex. The resulting solar cells show power conversion efficiencies exceeding 24% and enhanced operational stability, maintaining over 95% of their performance without encapsulation for 500 h under continuous operation. Moreover, the host contributes to binding lead ions, reducing their environmental impact. This supramolecular strategy illustrates the broad implications of host–guest chemistry in photovoltaics.text::journal::journal article::research article