Enhanced performance of dye-sensitized solar cells based on organic dopant incorporated PVDF-HFP/PEO polymer blend electrolyte with g-C₃N₄/TiO₂ photoanode

This work describes the effect of 2-aminopyrimidine (2-APY) on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) blend polymer electrolyte along with binary iodide salts (tetrabutylammonium iodide (TBAI) and potassium iodide (KI)) and iodine (I₂) were studied for enhancing the efficiency of the dye-sensitized solar cells (DSSCs) consisting of g-C₃N₄/TiO₂ composite as photoanode. The g-C₃N₄ was synthesized from low cost urea by thermal condensation method. It was used as a precursor to synthesize the various weight percentage ratios (5%, 10% and 15%) of g-C₃N₄/TiO₂ composites by wet-impregnation method. The pure and 2-APY incorporated PVDF-HFP/PEO polymer blend electrolytes were arranged by wet chemical process (casting method) using DMF as a solvent. The synthesized g-C₃N₄/TiO₂ composites and polymer blend electrolytes were studied and analyzed by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The ionic conductivity values of the pure and 2-APY incorporated PVDF-HFP/PEO blend electrolytes were estimated to be 4.53×10⁻⁵ and 1.87×10⁻⁴ Scm⁻¹ respectively. The UV–vis absorption spectroscopy was carried out for the pure and different wt% of g-C₃N₄/TiO₂ composites coated FTO films after N3 dye-sensitization. The 10 wt% g-C₃N₄/TiO₂ composite film showed a maximum absorption compared to the others. The DSSC assembled with 10 wt% g-C₃N₄/TiO₂ as photoanode using the pure polymer blend electrolyte exhibited a power conversion efficiency (PCE) of 3.17% , which was superior than that of DSSC based pure TiO₂ (2.46%). However, the PCE was increased to 4.73% for the DSSC assembled using 10 wt% g-C₃N₄/TiO₂ as photoanode with 2-APY incorporated polymer blend electrolyte. Hence, the present study is a successful attempt to provide a new pathway to enhance the performance of DSSCs. - Graphical abstract: In this study, the g-C₃N₄ was synthesized from low cost urea and it was used as a precursor to synthesize of g-C₃N₄/TiO₂ composite. The pure and 2-APY incorporated PVDF-HFP/PEO electrolytes were fabricated by solution casting method. A remarkably enhanced PCE of 4.73% was observed for 2-APY incorporated PVDF-HFP/PEO electrolyte with g-C₃N₄/TiO₂ composite photoanode based DSSC. - Highlights: • 2-APY added PVDF-HFP/PEO electrolyte was prepared by solution casting method. • The g-C₃N₄/TiO₂ composites were synthesized by wet-impregnation method. • DSSC with g-C₃N₄/TiO₂ and 2-APY added electrolyte showed the efficiency of 4.73 %. • The g-C₃N₄ and 2-APY can be a useful dopant to enhance the performance of DSSCs.