Facile synthesis of a hole transporting material with a silafluorene core for efficient mesoscopic CH3NH3PbI3 perovskite solar cells

A novel electron-rich small-molecule, 4,4′-(5,5-dihexyl-5H-dibenzo[b,d]silole-3,7-diyl)bis(N,N-bis(4-methoxyphenyl)aniline) (S101), containing silafluorene as the core with arylamine side groups, has been synthesized via a short efficient route. When S101 was incorporated into a CH3NH3PbI3 perovskite solar cell as a hole transporting material (HTM), a short circuit photocurrent density (Jsc) of 18.9 mA cm−2, an open circuit voltage (Voc) of 0.92 V, and a fill factor (FF) of 0.65 contributing to an overall power conversion efficiency (PCE) of ∼11% which is comparable to the PCE obtained using the current state-of-the-art HTM 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) (η = 12.3%) were obtained. S101 is thus a promising HTM with the potential to replace the expensive spiro-OMeTAD due to its comparable performance and much simpler and less expensive synthesis route.