Pyridine-Functionalized Fullerene Electron Transport Layer for Efficient and Flexible Perovskite Solar Cells

摘要

Designing low-temperature solution-processed electron transport layer (ETL) for perovskite solar cells (PSCs) is important to realize low-cost and large-scale manufacturing of PSCs. Herein, we successfully synthesized a novel pyridine-functionalized fullerene derivative [6,6]-(4-pyridinyl)-C_(61)-ethyl acid ethyl ester (PyCEE), which can act as an excellent ETL for n-i-p type PSCs. Due to its suitable energy levels, high electron mobility, and coordination interactions with the Pb~(2+) within perovskite, PyCEE-based PSCs displayed a power conversion efficiency (PCE) of 18.27% with dramatically suppressed hysteresis, superior to that of the TiO_2-based control devices. Benefitting from the low-temperature and solution processability of PyCEE, it was further applied in flexible PSCs and a PCE of 15.25% was obtained, which demonstrates its applicability in flexible PSCs and provides new opportunity for large-scale production and commercialization of PSCs.