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 0.01g of SiO2 nanofiber filler, 9.90×10−4scm−1, which represents a substantial increase over the 3.81×10−4scm−1 of a pristine polymer electrolyte. Furthermore, the addition of 0.01g of SiO2 nanofiber filler also produced the highest electron transport time of 1.47ms, an electron recombination time of 29.41ms, 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 0.01g of SiO2 nanofiber filler exhibiting both the lowest cell impedance (20.96Ω) and the highest solar conversion efficiency (4.85%) in this study.