The impact of immerssion time and thickness of TiO2 photoanode on power conversion efficiency of dye-sensitised solar cells using graphene quantum dots as photosensitiser

Abstract Scientists propose developing stable, efficient, cost-effective, and colorful ruthenium-free dyes to improve the performance of dye-sensitised solar cells (DSSCs), facilitating their commercialization and overcoming the limitation of ruthenium-based dyes. Therefore, graphene quantum dots (GQDs) as a photosensitiser, having unique and fascinating properties, have attracted the interest of researchers for them to be used in the fabrication of green DSSC based on titanium oxide nanoparticles (TiO2-NPs) as a photoanode. GQDs bear both the individual and attractive properties of the graphene nature as well as the size-resulted quantum effects. In addition to the unique electrical and optical properties of GQDs, their bandgap is lesser than 2.0 eV making them interesting material in the field of DSSCs. In this article, we fabricate a TiO2-NPs based DSSCs using GQDs green photosensitiser and investigate the impact of immersion time and photoanode layer thickness on the performance and power conversion efficiency (PCE) of fabricated DSSC. The optimized immersion time of TiO2 in GQDs green photosensitiser is analyzed to be 21 h and 40 μm thickness of the photoanode layer. The I–V result test indicates open circuit output potential difference (Voc) of 0.74 V, and short circuit current (ISC) of 6.62 mA with PCE of 2.76% and a fill factor (FF) of 56.