The preparation of highly flexible mesoporous TiC/CNF film for flexible dye-sensitized solar cells

The flexible TiC/carbon nanofiber (TiC/C NF) film was prepared by electrospinning, stabilization, and carbonization. All the obtained TiC/CNFs had rough surface and random orientation, and the TiC nanoparticles (NPs) were uniformly dispersed on the CNFs. With the increase of TiC NPs, the flexural property of TiC/CNF film increased. While, the electrical conductivity increased, reaching a largest value before decreasing as the amount of TiC NPs increases. These highly flexible films showed promising electrical conductivity and electrocatalytic activity. Hence, they were employed as counter electrodes (CEs) for flexible dye-sensitized solar cells (FDSSCs). After the optimization of the amount of TiC NPs in CNFs (when the Tip content in precursor was 12 wt%), a high conversion efficiency of 3.80% was obtained. This is due to its optimum electrical conductivity and catalytic active sites. Based on the optimum amount of TiC NPs, the mesopores TiC/CNF composite films were fabricated by the introduction of various amount of polymethyl methacrylate (PMMA) in an electrospun solution. With the ratio of PMMA/(PAN/PVP) increasing, the specific surface area and the electrical conductivity increased, reached the largest values corresponding to 1:1, and then decreased. The increased surface area and conductivity facilitated the diffusion of electrolyte and reduction of triiodide, resulting in the improvement of the properties of CEs. When the FDSSCs were assembled with mesoporous TiC/CNF films as CEs, the conversion efficiency can be further enhanced up to 4.47%, which can be even comparable to the Pt/FTO CE. Graphical abstract ᅟ