Nanosized Anatase TiO2 Single Crystals with Tunable Exposed (001) Facets for Enhanced Energy Conversion Efficiency of Dye-Sensitized Solar Cells

This paper reports the synthesis of nanosized TiO2 single crystals with different percentages of exposed (001) facets in the presence of HF solution. Various characterizations are conducted to understand the correlation between particle morphology, exposed (001) facets and photo-conversion efficiency of the nanosized anatase TiO2 single crystals. An enhancement in dye-sensitized solar cells (DSSCs) overall conversion efficiency is observed for the photoanode consisting of nanosized TiO2 single crystals with higher percentage of exposed (001) facets, increasing from 7.47%, 8.14% to 8.49% for the TiO2 single crystals with ca. 10%, 38%, and 80% percentage of exposed (001) facets. Experimentally confirmed by dark current potential and open-circuit voltage decay scans, such highly exposed (001) facets are not only favorable for more dye adsorption but also effectively retard the charge recombination process in DSSCs.