Hybrid polymer electrolyte composite with SiO2 nanofiber filler for solid-state dye-sensitized solar cells

SiO2 nanofibers were prepared by electrospinning method and incorporated as filler into a hybrid polymer matrix of poly(ethylene oxide) (PEO) and poly(vinylidene fluoride)-hexafluoropropylene (PVDF-HFP). The effectiveness of the SiO2 nanofiber-filled matrix as a polymer electrolyte for solid-state dye-sensitized solar cells (DSCs) was evaluated. The SiO2 nanofiber filler was found to increase the ionic conductivity, thereby improving the charge transport of the I−/I3− redox couple in the electrolyte. As a result, the efficiency of the DSCs was increased by up to 24% as compared with a pristine polymer electrolyte. The ionic conductivity was found to be greatest in the polymer electrolyte containing 0.01 g of SiO2 nanofiber filler, 9.90 × 10−4 s cm−1, which represents a substantial increase over the 3.81 × 10−4 s cm−1 of a pristine polymer electrolyte. Furthermore, the addition of 0.01 g of SiO2 nanofiber filler also produced the highest electron transport time of 1.47 ms, an electron recombination time of 29.41 ms, and a charge collection efficiency of 94.99%. The SiO2 nanofiber filler also greatly enhanced the interfacial stability between the polymer electrolyte and the semiconductor electrodes, with the hybrid polymer electrolyte containing 0.01 g of SiO2 nanofiber filler exhibiting both the lowest cell impedance (20.96 Ω) and the highest solar conversion efficiency (4.85%) in this study.