▎ 摘　　要

Self-assembly of reduced graphene oxide, zinc [5,10,15,20-tetrakis(2,6-dichlorophenyl) porphyrin] complex and CuO nanoparticles was performed through pi-pi stacking and hydrogen bonding using Calotropis procera plant to have a bio-nanocomposite (ZnPor/rGO/CuO). This green organic/inorganic ternary hybrid was constructed using bottom-up approach to have multiple electron transfer and characterized by SEM, TEM, XRD, EDX, elemental analysis, UV-Vis spectroscopy, and Cyclic voltammetry (CV). The bio-nanocomposite (ZnPor/rGO/CuO) possesses suitable energy level, high hole mobility, and excellent thermal stability. The obtained bio-nanocomposite was used as inorganic hole-transporting material (HTM) in carbon-based Perovskite Solar Cells (C-PSC). 9.8 is the best powder conversion efficiency of system in comparision with Spiro-OMeTAD as a commercial HTM. Its PCE is about 59% more than of PCE of control device (HTM free). This significant increase in PCE was due to the higher hole-extraction rate at carbon counterelectrode, in the presence of bio nanocomposite as a HTM confirming by Mott-Schottky analysis and the electrical conductivity. (C) 2021 The Author(s). Published by Elsevier B.V.