Effect of titanium dioxide nanofillers on the properties of gel-polymer electrolytes and power conversion efficiency of dye-sensitized solar cells

TiO₂ nanoparticles were gradually incorporated into a gel-polymer electrolyte to optimize the nanofiller composition to develop stable and highly efficient solid-state DSSCs. For this purpose, TiO₂ nanoparticles (13 nm) were amalgamated (0–25%) to the polyethylene oxide-based polyiodide gel-polymer electrolyte. The nanofiller-infused electrolytes were sandwiched within six-layer photoanodes sensitized with N719 dye and platinum electrodes to assemble DSSCs. The cell efficiency and electrolyte conductivity are highly dependent on the TiO₂ nanoparticle content. The electrolytic conductivity and DSSC efficiency are maximum at the optimal nanofiller percentage of 17.50%. Nanofiller-free control cell has an efficiency of 5.70%, while the optimally nanofiller-infused DSSC shows the highest efficiency of 7.30%, yielding a 28.1% efficiency improvement. This boost in efficiency resulted in enhanced conductivity, suppression of charge recombination due to the addition of smaller-sized nanoparticles, and the utilization of an appropriate photoanode. This study uncovers valuable insights into developing more efficient DSSCs by integrating nano-additives in the electrolyte.