Molecular “Flower” as the High-Mobility Hole-Transport Material for Perovskite Solar Cells

To develop novel hole-transport materials (HTMs) with less synthetic steps is still a great challenge. Here, a small molecule hexakis[4-( N, N -di- p -methoxyphenylamino)phenyl]benzene ( F-1 ) was successfully synthesized by a relatively simple scenario. F-1 exhibits a deep highest occupied molecular orbital energy level of −5.31 eV. Notably, F-1 also features 2 times higher hole mobility of 4.98 × 10 –4 cm 2 V –1 s –1 than that of the mostly used 2,2′,7,7′-tetrakis( N, N -bis(4-methoxyphenyl)amino)-9,9′-spirobifluorene (spiro-OMeTAD). Consequently, F-1 -based perovskite solar cells (PSCs) show markedly improved performance compared with spiro-OMeTAD-based ones. These results indicate such a material can be a promising HTM candidate to boost the overall performance of the PSC.