Flexible PET/(PET-TiO2) core/shell nanofibrous mats as potential photoanode layer for dye-sensitized solar cells, DSSCs

In this detailed study, high porous flexible structures composed of polyethylene terephthalate (PET) and a PET composite comprised of titanium dioxide (PET-TiO2) core/shell nanofibrous mats were developed using coaxial electrospinning technique. Two different TiO2 shapes (nanobars and nanorhombics) were developed, using the solvothermal synthesis method, then incorporated at various contents (0–20 wt%) in the shell layer of the nanofiber to improve the optical, thermal, and mechanical properties of their corresponding fibrous mats to use them as alternative porous structures to the brittle porous TiO2 based photoelectrode presently used. The surface morphology, porosity, specific surface area, thermal stability, dye adsorption, optical and mechanical properties of the so developed nanofibrous mats were investigated. Emphasis was to the effect of solvent miscibility and solvent composition on fibrous mats' morphology. The successful incorporation of TiO2 nanoparticles inside the nanofibers’ shell was confirmed by various characterizations techniques. It was observed that addition of up to 15 wt% TiO2 shifted the UV–Visible absorption of the of the so developed nanofibrous mats to larger wavelength. Moreover, PET/(PET-TiO2) core/shell nanofibrous mats obtained with nanobars TiO2 showed higher thermal stability due to a better TiO2/PET interfacial interaction. Photoluminescence results confirmed the efficient charge transfer between TiO2 nanoparticles and PET with a minimum recombination of the photogenerated charges.