High-performance hybrid perovskite solar cells with polythiophene as hole-transporting layer via electrochemical polymerization

Thin polythiophene film prepared via electrochemical polymerization has been successfully used as the hole-transporting layer in CH3NH3PbI3 perovskite solar cells, affording a series of ITO/polythiophene/CH3NH3PbI3/C-60/BCP/Ag devices. The highest occupied molecular orbit (HOMO) and lowest unoccupied molecular orbit (LUMO) of the polythiophene film are determined as -5.20 eV and -3.12 eV, respectively, which match well with that of CH3NH3PbI3 perovskite material. In addition, a promising power conversion efficiency of 11.8%, featuring a high fill factor of 0.707, good open voltage of 1.03 V and short current density of 16.2 mA cm(-2), has been obtained, which renders polythiophene as an effective competitor to spiro-OMeTAD in perovskite solar cells. Furthermore, this work provides a simple, prompt, controllable and economic approach for the preparation of hole-transporting layer, which would undoubtedly yield new insight into the industrial production of perovskite solar cells.