Fluorination on cyclopentadithiophene-based hole-transport materials for high-performance perovskite solar cells.

A new class of fluorinated cyclopenta[2,1-:3,4-']dithiophene (CPDT)-based small molecules, namely YC-oF, YC-mF, and YC-H, are demonstrated as hole-transporting materials (HTMs) for high-performance perovskite solar cells (PSCs). PSCs employing YC-oF as the HTM delivered an excellent efficiency of 22.41% with encouraging long-term stability.