C60-assisted crystal engineering for perovskite solar cells with enhanced efficiency and stability

Abstract Perovskite solar cells (PSCs) are promising low-cost photovoltaic technologies with high solar-to-electric power conversion efficiency (PCE). Preparation of high-quality perovskite thin films is key to achieve high performance for PSCs. In this work, a small amount of fullerene (C 60 ) is added to toluene in the antisolvent dripping process. The resulting C 60 -containing perovskite solar cells show better stability, PCE, and reproducibility than the device fabricated by using only toluene as an antisolvent. C 60 adheres to the pinhole and grain boundaries of perovskite film, improves perovskite crystallinity, and enhances absorption without changing the thickness of the film. It also plays a passivation role on the surface of perovskite film and prevents the migration of I and Pb elements. The change of the morphology and the passivation of the interface increase the FF and J SC of C 60 -containing device. The best PCE of 19.8% is obtained. The PCE of encapsulated PSCs still maintains 70% of its initial value after 1000 h continuous full sun illumination.