A multifunctional and scalable fullerene electron transporting material for efficient inverted perovskite solar cells and modules

The interfacial properties between charge transporting material and perovskite (PVSK) play critical roles in governing the photovoltaic performances of perovskite solar cells (PVSCs). Herein, we develop a multifunctional fulleropyrrolidine (FMG) as an electron transporting material (ETM), which facilitates the construction of efficient and stable inverted PVSCs and modules. It revealed that the facile and scalable FMG possesses not only excellent electron extraction capabilities, but also multi-groups to simultaneously passivate PVSKs via Lewis acid-base and hydrogen bonding interactions. The coating of FMG onto PVSK interestingly yields a dense and interactive layer with the graded ETM-PVSK heterojunction architecture. As results, FMG-based PVSCs demonstrate a champion efficiency of 23.8%, outperforming 21.0% of PCBM-based devices. FMG could also be utilized to improve photovoltaic performance of large-scale modules. In addition, FMG has successfully elongated the lifetime of the corresponding PVSCs, maintaining 85% of the initial performance after the continuous 60-day one sun equivalent illumination in ambient.