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

Abstract

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 (C60) is added to toluene in the antisolvent dripping process. The resulting C60-containing perovskite solar cells show better stability, PCE, and reproducibility than the device fabricated by using only toluene as an antisolvent. C60 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 JSC of C60-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.