Carbon nanofibers (CNFs) are promising materials for the construction of energy devices, particularly organic solar cells. In the electrospinning process, polyacrylonitrile (PAN) has been utilized to generate nanofibers, which is the simplest and most popular method of creating carbon nanofibers (CNFs) followed by carbonization. The CNFs are coated on stainless steel (SS) plates and involve an electropolymerization process. The prepared Cu, CNF, CNF–Cu, PANI, PANI–Cu, CNF–PANI, and CNF–PANI–Cu electrode materials’ electrical conductivity was evaluated using cyclic voltammetry (CV) technique in 1 M H2SO4 electrolyte solution. Compared to others, the CNF–PANI–Cu electrode has higher conductivity that range is 3.0 mA. Moreover, the PANI, CNF–PANI, and CNF–PANI–Cu are coated on FTO plates and characterized for their optical properties (absorbance, transmittance, and emission) and electrical properties (CV and Impedance) for organic solar cell application. The functional groups, and morphology-average roughness of the electrode materials found by FT–IR, XRD, XPS, SEM, and TGA exhibit a strong correlation with each other. Finally, the electrode materials that have been characterized serve to support and act as the nature of the hole transport for organic solar cells.

Electrospun and electropolymerized carbon nanofiber–polyaniline–Cu material as a hole transport material for organic solar cells
    Abstract
    1 Introduction
    2 Experimental section
        2.1 Materials
        2.2 Preparation of carbon nanofiber (CNF)
        2.3 Fabrication of a carbon nanofiber (CNF)-coated electrode
        2.4 Electrolyte preparation for polymerization
            2.4.1 Preparation of aniline monomer
            2.4.2 Preparation of copper monomer
            2.4.3 Preparation of a copper–aniline monomer mixture
        2.5 Electropolymerization of aniline
    3 Results and discussion
        3.1 Cyclic voltammetry study
        3.2 Cyclic voltammetry and impedance study of FTO plate
        3.3 Optical study
        3.4 Fluorescence and FT-IR study
        3.5 XRD and TGA analyses
        3.6 XPS spectra
        3.7 Structure morphology study
        3.8 Current–voltage (I–V) characteristicsstudy
    4 Conclusions
    Anchor 23
    Acknowledgements 
    References

• Esakkimuthu Shanmugasundaram(Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003, Tamil Nadu, India)
• Chandramohan Govindasamy(Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia)
• Muhammad Ibrar Khan(Department of Community Health Sciences, College of Applied Medical Sciences, King Saud University, P.O. Box 10219, Riyadh 11433, Saudi Arabia)
• Vigneshkumar Ganesan(Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003, Tamil Nadu, India)
• Vimalasruthi Narayanan(Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003, Tamil Nadu, India)
• Kannan Vellaisamy(Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003, Tamil Nadu, India)
• Rajaram Rajamohan(Organic Materials Synthesis Laboratory, School of Chemical Engineering, Yeungnam University, Gyeongsan 38541, Republic of Korea)
• Stalin Thambusamy(Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003, Tamil Nadu, India)