Effect of Co2+ substitution into zinc oxide host lattice via electrodeposition cum hydrothermal approach for enhancing dye synthesized solar cell performance

Pure and cobalt-doped (1, 3, 3.5 wt%) zinc oxide nanostructures were synthesized by two-step method. At first, zinc/cobalt alloys were deposited on copper substrate via electrodeposition then hydrothermally oxidized to get hierarchical nanostructures (nanorods). X-ray diffraction spectroscopy (XRD) results confirmed the deposition of zinc/cobalt alloys and their subsequent oxidation after hydrothermal treatment. Scanning electron microscopy (SEM) analysis revealed that cobalt doping has enhanced the aspect ratio (8.30 to 20) of nanorods with tapered end morphology which helped to improve the anchoring of dye molecules. Diffuse reflectance spectroscopy (DRS) analysis indicated that cobalt doping has decreased the band gap energy from 3.257 to 3.225 eV by exchange interaction among sp-d electrons. The synthesized photo-anode compositions were further used to fabricate dye-sensitized solar cells (DSSC). The J-V characteristic curves of DSSC revealed that photoconversion efficiency has been enhanced three folds due to larger surface area and higher dye (N719) loading ability of cobalt-doped zinc oxide composition (3.5 wt% Co).

Automated summary

Pure and cobalt-doped zinc oxide nanostructures were successfully synthesized using a two-step method. Cobalt doping enhanced the aspect ratio of nanorods and improved the anchoring of dye molecules, while reducing the band gap energy. This resulted in a three-fold increase in the photoconversion efficiency of dye-sensitized solar cells.