Michael Graetzel, Shaik Mohammed Zakeeruddin, David Lyndon Emsley, Ursula Röthlisberger, Felix Thomas Eickemeyer, Jovana Milic, Michael Allan Hope, Marko Mladenovic, Ulf Anders Hagfeldt, Hong Zhang, Dan Ren, Zaiwei Wang, Paramvir Ahlawat, Aditya Mishra, Zhaowen Dong, Farzaneh Jahanbakhshi, Anurag Krishna, Jinming Guo, Olivier Ouellette, Zhiwen Zhou, Tzu-Sen Su
Formamidinium 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.
2021