TiO2 nanosheets with highly exposed (001)-facets for enhanced photovoltaic performance of dye-sensitized solar cells

Abstract

In this study, TiO2 nanosheets having highly exposed (001)-facets were synthesized and compared with the commercially available P25. The results indicate that the synthesized TiO2 nanosheets have a smaller specific surface area and yet with a higher dye-loading capacity. This gives a 26.7% enhancement in cell efficiency (η) when compared with the corresponding dye-sensitized solar cell (DSSC) made of P25. Abundant characterization data were obtained to understand the 001 surface activity of TiO2 nanosheets and their role on the device performance. Reasonable mechanism is proposed to explain the higher dye-loading capacity on the smaller specific surface area. Besides, according to the normalized photocurrent of TiO2 nanosheets, the longer wavelength region (600-800nm) contributes 52.9% of the integrated photocurrent density; this result further confirms their superior light scattering properties in the longer wavelength region. An optimal η of 8.77% is obtained for the DSSC with the TiO2 nanosheets film, as compared to that of the cell with the P25 film (6.92%). © 2014 Elsevier Ltd.