Electrodeposited NiCoO₂@CNTs fiber as efficient counter electrode in wire-shaped dye-sensitized solar cells

One-dimensional wire-shaped dye-sensitized solar cells (DSSCs) are promising flexible energy conversion devices for new generation wearable microelectronics. Typically, Pt-based expensive materials are employed as counter electrodes for device fabrication along with photoanode and electrolyte. In this work, a facile electrodeposition approach has been adopted to deposit bimetallic oxide of cobalt and nickel over the surface of carbon nanotube-based fiber and used it as counter electrodes in fiber-shaped DSSCs. Modified Ti wire (TiO₂ nanotubes/N719 dye) was used as a photoanode and NiCoO₂ modified CNTs fiber twisted around the photoanode operated as a counter electrode in fibrous DSSCs. Electron transfer behavior of iodide/triiodide (I⁻/I₃⁻) redox couple at counter electrode studied via cyclic voltammetry (CV) which revealed that the modified CNTs fiber electrode performs better as compared to Pt wire and pristine CNTs fiber. The lower value of charge transfer resistance was calculated via EIS (electrochemical impedance spectroscopy), which also suggested a facile reduction of triiodide to iodide at the counter electrode. The outcomes realized that the electrodeposited CoNi-oxide nanoparticles over the CNTs fiber significantly improve the device performance because of the harmonious effect of active sites and inner pathways facilitated by the NiCoO₂ nanoparticles and CNTs fiber, respectively. This work recommends a facile method for the fabrication of efficient electrodes for flexible and wearable energy harvesting devices.