Multimodal host-guest complexation for efficient and stable perovskite photovoltaics

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 photo-induced 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.

Hong Zhang, Felix Thomas Eickemeyer, Zhiwen Zhou, Marko Mladenović, Farzaneh Jahanbakhshi, Lena Merten, Alexander Hinderhofer, Michael A. Hope, Olivier Ouellette, Aditya Mishra, Paramvir Ahlawat, Dan Ren, Tzu-Sen Su, Anurag Krishna, Zaiwei Wang, Zhaowen Dong, Jinming Guo, Shaik M. Zakeeruddin, Frank Schreiber, Anders Hagfeldt, Lyndon Emsley, Ursula Rothlisberger, Jovana V. Milić, Michael Grätzel