Enhancing the electrical properties of dye-sensitized solar cells by carbon-free titanium gel via a non-hydrolytic method

Abstract

Abstract In this study, a carbon free titanium gel was synthesized following a non-hydrolytic method, and was used as a binder for the TiO 2 electrodes of dye-sensitized solar cells (DSSCs). The concentration of the binding anode paste was optimized by using varying levels of titanium gel (10, 13, and 16 wt%) to fabricate the anode paste of DSSCs. The TiO 2 layers printed on transparent conducting oxide (TCO) glass substrates had good shape-retention without an organic binder after doctor blade printing, and the amorphous titanium gel crystallized into a pure anatase form from annealing at 450 °C for 1 h. The SEM and HR-TEM analyses revealed a mesoporous TiO 2 layer, and a uniform TiO 2 coating of ∼1.5 nm P-25-TiO 2 nanoparticles. This coating enhanced excited electron transfer and electrical contact between particles. The open-circuit voltage of DSSCs increased by about 50 mV more than that of the DSSCs with an organic-based binder. Furthermore, the dark saturation current of DSSCs fabricated with 10 wt% titanium gel decreased by 1/6 than organic binder-based DSSCs. In summary, the power conversion efficiency of DSSCs fabricated with a titanium gel binder was enhanced by 15.4%, compared to that of organic binder-based DSSCs.