Addition of Electrospun TiO2 Nanofibers for Improving the Charge Capabilities of Polymer Electrolyte-Based DSSCs

TiO2 nanofibers were fabricated by electrospinning techniques for application to polymer matrix electrolyte-based dye-sensitized solar cells (DSSCs). The prepared TiO2 nanofibers exhibited an anatase phase of 67% and diameters of 120 nm; they were used as additives into the PEO-(PVDF-HPF) polymer matrix electrolyte-based DSSCs for improving the electron charge transfers. The addition of TiO2 nanofibers increased the ionic conductivity, thereby improving the charge transport of the I-/I-3(-) redox couple into the polymer matrix electrolyte. A polymer matrix electrolyte containing 0.02 g of TiO2 nanofibers (TN002) showed the best efficiency among the evaluated DSSCs; the efficiency increased by up to 37.34% compared with a pure polymer matrix electrolyte (TN000). Furthermore, the TN002 electrolyte also produced the fastest electron transport time of 1.42 ms, the highest electron recombination time of 31.72 ms, and a charge collection efficiency of 95.53%. The diffusion coefficiency and diffusion length were 1.23 x 10(-4) cm(2) s(-1) and 20.28 mu m, respectively. TiO2 nanofiber additives also greatly enhanced the interfacial stability between the polymer matrix electrolyte and the photoelectrode, with TN002 exhibiting both the lowest cell impedance (15.35 Omega) and the highest solar conversion efficiency (5.37%). (C) 2014 The Electrochemical Society. All rights reserved.