Rapid electron injection in nitrogen- and fluorine-doped flower-like anatase TiO₂ with {001} dominated facets and dye-sensitized solar cells with a 52% increase in photocurrent

Nitrogen- and fluorine-doped flower-like anatase TiO₂ (NF-TiO₂) with {001} dominated facets was fabricated by a facile hydrothermal method. We investigated its electrical and optical properties, applied it in dye-sensitized solar cells as an electrode material, and achieved an improved conversion efficiency of 8.20%. There was a 52% increase in the photocurrent and 22% improvement in the conversion efficiency. Such improvements mainly arise from the positive-shift flat band, increasing the driving force of electrons and then improving the electron injection efficiency from the lowest unoccupied molecular orbital (LUMO) of the dye and the conduction band of TiO₂; from the incorporation of the flower-like anatase NF-TiO ₂ crystals with exposed {001} facets, serving as effective light-scattering centers and improving the reactivity, both important attributes for achieving a higher light harvesting and thus an improved J_sc and conversion efficiency; and from the narrowed band gap, expanding the response in the visible region and increasing the utilization percentage of visible light. This study provides straightforward evidence for the nitrogen- and fluorine-doped {001} facets dominated anatase TiO₂, and with these merits, NF-TiO₂ with {001} dominated facets may find its way in various environmental and energy-related applications.