Optimization of quasi-solid-state dye-sensitized photovoltaic fibers using porous polymer electrolyte membranes

Abstract

Quasi-solid-state dye-sensitized photovoltaic fibers are fabricated using poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP)/polyethylene oxide-co-polypropylene oxide-co-polyethylene oxide (P123) porous polymer electrolyte membranes and their photocurrent–voltage (I–V) characteristics are presented. The working electrode is a titanium wire coated with a dye-adsorbed TiO2 layer and the counter electrode is a platinum wire coated with a porous polymer electrolyte membrane. Different pore structures in the PVdF-HFP/P123 polymer membranes are obtained by varying the blend ratio of the polymers. The overall pore volume increases with higher P123 content, improving the ionic conductivity of the porous polymer electrolyte membrane by facilitating the uptake of electrolyte solution. Consequently, quasi-solid-state dye-sensitized photovoltaic fibers fabricated with membranes higher in P123 content give superior performances. The photoelectrochemical characteristics of the photovoltaic fiber are also dependent upon the thickness of the TiO2 layer and the twist pitch length of the counter electrode. The best performing photovoltaic fiber in this study exhibits a short-circuit current density (Jsc) of 2.117 mA cm−2, open-circuit voltage (Voc) of 0.6932 V, fill factor (FF) of 0.7015 and an energy conversion efficiency (η) of 1.029%. Finally, the possibility for large-scale application of the quasi-solid-state dye-sensitized photovoltaic fiber is confirmed by implementing a mesh-type weave structure based on fiber-like electrodes.