Simply designed carbazole-based hole transporting materials for efficient perovskite solar cells

Efficient and low-cost hole transporting materials are required for the development of perovskite solar cells. Herein, simple molecular designed hole transporting materials (HTM), such as the carbazole derivative CzP and a novel fluorinated analogue CzPF, are investigated in planar perovskite solar cells. A comparison of the CzP and CzPF properties clearly demonstrates that the addition of a fluorine atom increases the hole mobility. A power conversion efficiency close to 13% in MAPbI₃ planar structure devices was obtained using these amorphous carbazole-based HTMs. This result clearly demonstrates that both CzP and CzPF materials, owing to improved charge transfer and low hysteresis, lead to similar photovoltaic performances compared to the commonly used spiro-OMeTAD.