Organic small molecules modify electron transport layer to enhance performance of inverted perovskite solar cells

An effective approach to address issues such as interface charge recombination, electron extraction and transport, and poor interface contact on perovskite involves the development of organic electronic transport layer (ETL) of perovskite solar cells (PSCs). Here, a small molecule, AQ X -OCH 2 CH 2 CF 3 , designated as CQF, is designed, synthesized, and incorporated into [6,6]-Phenyl C 61 -butyric acid methyl ester (PCBM) to serve as an ETL in the fabrication of inverted PSCs. Multiple experimental analyses confirm that CQF effectively suppresses charge recombination, enhances electron extraction and transport, and improves the contact between the ETL and perovskite layer. Consequently, PSCs utilizing PCBM: CQF as ETL achieve a notable power conversion efficiency (PCE) of 18.15% with minor hysteresis effect. The devices maintain over 90% of their initial PCE after over 1,000 h under one sun illumination in a moist air atmosphere. This research presents a straightforward and effective method for enhancing both the efficiency and stability of PSCs.