Strategic design and fabrication of rGO encapsulated single phase CdFe2O4 nanohybrid for Pt-free dye-sensitized solar cells

Recently, Pt-free counter electrodes (CEs) have emerged as cost-effective alternatives for components in dye-sensitized solar cells (DSSCs), garnering significant interest in the field. In this regard, we have developed a novel hybrid composite consisting of 2D spinel phase CdFe₂O₄ and 2D reduced graphene oxide (rGO) nanosheets through a one-step ultrasonic-assisted hydrothermal method to serve as the CE for dye-sensitized solar cells. The crystallinity, morphology and textural properties of the composites were analyzed in detail using X-ray diffraction, scanning electron microscopy (FE-SEM), Transmission electron microscope, N₂ adsorption–desorption, X-ray photo electron spectroscopy techniques. The findings obtained through electrochemical impedance spectroscopy, cyclic voltammetry and Tafel polarization measurements indicated that the CdFe₂O₄/rGO demonstrated robust electrocatalytic activity, enabling effective I⁻/I₃⁻ redox reactions and notably reduced charge transfer resistance in comparison with pristine CdFe₂O₄. Specifically, the DSSC utilizing the CdFe₂O₄/rGO CE attains a power conversion efficiency of 8.52%, significantly surpassing the efficiencies of 4.02%, 5.21%, and 6.64% observed in solar cells employing CdFe₂O₄, CdFe₂O₄-rG1, and CdFe₂O₄-based counter electrodes, respectively. Therefore, the CdFe₂O₄/rGO hybrid composite serves as a cost-effective alternative to high-cost Pt as a CE, thereby facilitating cost-efficiency in DSSCs in the future.