Enhanced photovoltaic performance of quasi-solid-state dye-sensitized solar cells by incorporating a quaternized ammonium salt into poly(ethylene oxide)/poly(vinylidene fluoride-hexafluoropropylene) composite polymer electrolyte

Quasi-solid-state dye-sensitized solar cells (DSSCs) are fabricated using tetraethylammonium tetrafluoroborate (Et4NBF4)-modified poly(ethylene oxide)/poly(vinylidene fluoride-hexafluoropropylene) (PEO/P(VDF-HFP)) composite polymer electrolytes (CPEs) along with KI and I2. Compared to the original CPE, the addition of Et4NBF4 mainly changes the conformation of the polymer structure, reduces the crystallinity of the polymer electrolyte specifically, and hence, increases the triiodide diffusion coefficient and the ionic conductivity, leading to the notable improved photovoltaic performance of DSSC. The DSSC based on the Et4NBF4 (0.15 g)-modified CPE exhibits the best performance, with a short current density of 14.70 mA cm−2 and a photoenergy conversion efficiency of 6.243% under an irradiance of 96.17 mW cm−2.