Publication date: 23rd October 2020
Perovskite solar cells (PSCs) have attracted a significant attention as a rapidly developing 3rd generation photovoltaic technology with a record efficiency of 25.2%. However, the commercialization of PSCs is strongly impeded by their low operational stability under realistic conditions [1], [2]. One of the mechanisms of PSCs degradation is based on the interaction of perovskite decomposition products with charge transport interlayers and electrodes [3]. We showed previously that chemical reaction at the interface between the perovskite absorber and [60]PCBM (phenyl C61 butyric acid methyl ester) used as electron transport layer (ETL) is largely responsible for the degradation of p-i-n perovskite solar cells [4]. Therefore, improving operational stability of p-i-n PSCs requires replacing fullerene-based ETLs with some alternative materials that must be chemically inert with respect to complex lead halides.
In this work, a novel n-type polymer with pyrrolo[3,4-c]pyrrole-1,4-dione building blocks was designed and investigated as electron transport material (ETL) for perovskite solar cells. Using the optimized blend of the synthesized polymer with the fullerene derivative [60]PCBM as ETL provided >16% device efficiency and good operational stability within 1200 hours under continuous light exposure.