Effects of tetrabutoxytitanium on photoelectrochemical properties of plastic-based TiO2 film electrodes for flexible dye-sensitized solar cells

The flexible DSSCs based on conducting plastic substrates are fabricated using electrodes made of tetrabutoxytitanium (TBOT) mixed with P25 TiO₂ nanoparticles at low temperature. To investigate the effects of TBOT on the flexible dye-sensitized solar cells, electrochemical impedance spectroscopy (EIS) is performed in the dark and under illumination conditions. Resistances for electron transport through TiO₂, charge-transfer resistance related to the TiO₂/redox electrolytes interface recombination, electron transport time and electron lifetime are quantified under different weight ratios of TBOT/P25. Additionally, the photovoltaic characteristics I-V curves and incident photon to current conversion efficiencies (IPCE) of flexible anodes made of different weight ratios of TBOT/P25 are obtained as well. It is found that the electrode under weight ratio 0.17 has the smallest inherent resistance, longest electron transport time and electron lifetime, lowest recombination rate and best performance with conversion efficiency 3.94%. These results indicate that after the weight ratios of TBOT/P25 is optimized, TBOT could enhance the interconnection between the TiO₂ particles, improve the conductivity of the electrode and decrease the charge recombination. Above results demonstrate that adding TBOT to TiO₂ is an easy and efficient method to improve the performance of the flexible DSSC fabricated at low temperature.