Enhancing charge transport performance of perovskite solar cells by using reduced graphene oxide-cysteine/nanogold hybrid material in the active layer

•Conductive networks of reduced graphene oxide-cysteine/nanogold (rGO-CysAu) hybrid material were incorporated into perovskite thin films.•Inverted PVSCs with ITO/NiOx/MAPbI3:1%-urea:rGO-CysAu/PCBM/BCP/Ag structure was fabricated.•The additives improved charge transfer, which reduced charge recombination and boundary impedance.•PVSCs with rGO-CysAu had an improved average efficiency of 20.59% compared to 18.32% for control cells.