Effectual application of green synthesized Co-doped NiO and Ce:Co-doped NiO nanomaterials in devising photo-cathode for dye-sensitized solar cells

P-type dye-sensitized solar cells have been fabricated with the sensitizer derived from tender coconut husk and Rhodamine B incorporated with and without co-doped (Co and Ce) nickel oxide (NiO) nanoparticles. NiO nanoparticles are obtained via green synthesis using the mesocarp of tender coconut. Graphene-coated FTO and I⁻/I³⁻ have been used as counter cathode and electrolyte, respectively, in the cells. The cubic structure was confirmed from XRD spectra, and Debye–Scherrer and Williamson-Hall equations were used for the evaluation of crystalline size (13.3 and 8.5 nm) and parameters of dislocation density, etc. Fingerprints of the samples by molecular vibrations were found using FTIR and UV–visible spectroscopy. SEM imaging has been recorded for both the NiO nanoparticles. The fabricated solar cells were subjected to JV characterization studies. Co-doped (Co and Ce) solar cell has shown better efficiency of 0.259% with short circuit current density and open circuit voltage of 1.382 mA/cm² and 0.387 V, respectively.