Multifunctional sulfonium-based treatment for perovskite solar cells with less than 1% efficiency loss over 4,500-h operational stability tests
Jiajia Suo, Bowen Yang, Edoardo Mosconi, Dmitry Bogachuk, Tiarnan A. S. Doherty, Kyle Frohna, Dominik J. Kubicki, Fan Fu, YeonJu Kim, Oussama Er‐raji, Tiankai Zhang, Lorenzo Baldinelli, Lukas Wagner, Ayodhya N. Tiwari, Feng Gao, Andreas Hinsch, Samuel D. Stranks, Filippo De Angelis, Anders Hagfeldt
Abstract
Abstract The stabilization of grain boundaries and surfaces of the perovskite layer is critical to extend the durability of perovskite solar cells. Here we introduced a sulfonium-based molecule, dimethylphenethylsulfonium iodide (DMPESI), for the post-deposition treatment of formamidinium lead iodide perovskite films. The treated films show improved stability upon light soaking and remains in the black α phase after two years ageing under ambient condition without encapsulation. The DMPESI-treated perovskite solar cells show less than 1% performance loss after more than 4,500 h at maximum power point tracking, yielding a theoretical T 80 of over nine years under continuous 1-sun illumination. The solar cells also display less than 5% power conversion efficiency drops under various ageing conditions, including 100 thermal cycles between 25 °C and 85 °C and an 1,050-h damp heat test.