RF plasma-enhanced graphene–polymer composites as hole transport materials for perovskite solar cells

Nanocomposites of graphene (GR) with polythiophene (PTh) or poly(3,4-ethylenedioxythiophene) (PEDOT) through a versatile and environmentally benign process, utilizing radio frequency (RF) plasma polymerization, were made. The morphological characterization of these nanocomposites was performed using various microscopy techniques and it revealed that PTh or PEDOT is coated on the GR surface. The surface properties of the GR nanocomposites were also determined using Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) analysis. The nanocomposites obtained were highly cross-linked with amorphous structure and exhibited homogeneous distribution of conducting polymers of PTh and PEDOT on the GR surface. The obtained nanocomposites were doped with iodine (I₂) to tune the conductivity. The developed GR nanocomposites were then used as hole-transporting layers for perovskite solar cell fabrication. The fabricated devices yielded a power conversion efficiency of 8.79 and 4.95% for PEDOT/GR and PTh/GR, respectively.