Photovoltaic performance evaluation of dye sensitized solar cells made using a quasi-solid state electrolyte and a low-cost pencil graphite counter electrode

We developed dye-sensitized solar cells (DSSCs) employing quasi-solid state electrolytes and low-cost pencil graphite counter electrode (CE), unlike the conventional DSSCs that use liquid electrolyte and expensive platinum CE. Two distinct devices are developed, utilizing N3 and N719 dyes as sensitizers in conjunction with TiO₂ semiconducting oxide. FESEM studies revealed a more uniform surface coverage and fewer surface voids in the N3 dye-TiO₂ film. The quasi-solid state electrolytes are formulated using poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) as a polymer membrane. A comparative assessment of device performance reveals that DSSCs sensitized with N3 dye exhibit a notable power conversion efficiency (PCE) of 3.43%, outperforming DSSCs sensitized with N719 dye, which registered a PCE of 2.78%. Furthermore, the underlying factors driving this difference in photovoltaic performance are recognized by conducting a comprehensive analysis. Additionally, we identified and outlined the performance-limiting factors specific to graphite CE-based DSSCs.