A novel preparation of small TiO2 nanoparticle and its application to dye-sensitized solar cells with binder-free paste at low temperature

TiO2 nanoparticles with diameter < 10 nm were synthesized by a facile, non-hydrothermal method at low temperature. A porous TiO2 film electrode consisting of the obtained small TiO2 nanoparticles and commercial TiO2 nanoparticles without any organic binder was prepared at low temperature. The photovoltaic performance of the solar cell based on the TiO2 electrode was investigated by the current-voltage and electrochemical impedance spectra. All the experimental results indicate that the addition amount of the small TiO2 nanoparticles in the binder-free paste affects the photovoltaic performance of the photoelectrode greatly. The overall energy conversion efficiency of the optimized binder-free photoelectrode achieves 3.53% without high-temperature sintering. Additionally, the performance of the small particles derived from this facile method can be comparable with that of small ones obtained from traditionally hydrothermal method, indicating the small particles in our study can be applied to flexible dye-sensitized solar cells. And the present low-temperature preparation of photoelectrode containing small TiO2 nanoparticles shows an encouraging performance on both conductive glass and plastic substrates and could be suited in the industrial and large-scale application due to its low energy cost and relatively high conversion efficiency.