Stable and efficient star-shaped hole transporting materials with EDOT moiety as side arm for perovskite solar cells

Abstract Two novel star-shaped hole transporting materials (HTMs). i.e. [BMPA-EDOT] 3 -TPA and [BMPA-BTD] 3 -TPA with EDOT or BTD moiety as side arm have been designed and synthesized. The optical and electronic properties of these HTMs were modified by changing the side arms. Surprisingly, the cell performance was dependent on the moietys such as EDOT or BTD of side arms. Perovskite solar cells with [BMPA-EDOT] 3 -TPA gave a short circuit photocurrent density ( J sc ) of 21.01 mA cm −2 , an open circuit voltage ( V oc ) of 0.916 V, and a fill factor ( ff ) of 0.67, corresponding to an overall conversion efficiency of 12.92%.