TiO 2 nanowires with a diameter of ∼150 nm, length of ∼3-4 µm, and aspect ratio of 10:1, were prepared by ultrasonically dispersing electrospun continuous nanofibers in monocarboxylic acids. The resulting pastes were used for making nanowire films on conducting glass substrates with thicknesses in the range of 500 nm to 100 µm, good adhesion, and high nanowire packing. These films were used to fabricate dye-sensitized solar cells using the D131 dye and the iodide/triiodide electrolyte. Transient photocurrent measurements showed a high electron diffusion coefficient in those nanowire films. The measured diffusion coefficient in those TiO 2 nanowires was orders of magnitude higher than that observed in nanoparticles under similar experimental conditions. The charge-transport mechanism in the nanowire sample is discussed in support with the measured open-circuit voltage decay curves.

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One‐dimensional nanostructures of niobium‐doped anatase TiO2 (Nb:TiO2) up to 5 at.% Nb were synthesized by electrospinning a polymeric solution containing titanium and niobium precursors and subsequent annealing. Thus obtained fibers had diameter ∼150 nm. The undoped TiO2 fibers were constituted by larger single crystalline grains of size ∼50 nm, whereas the doped ones had decreased grain sizes (∼30 nm) under similar processing conditions. The Nb doping decreased the BET surface area of TiO2. A strain‐induced lattice contraction was observed in Nb:TiO2. The continuous nanofibers were shortened to nanowires (NW) of aspect ratio 10:1 by ultrasonically dispersing them in acetic acid, which were developed as films of thickness ∼8–13 μm onto conducting glass substrates. The TiO2 and Nb:TiO2 nanowire films were further sensitized by a dye; the amount of dye anchored was found to decrease with increase in the dopant concentration. The dye‐sensitized solar cells fabricated using the doped fibers, although with a nominally increased current density (JSC), have reduced efficiency due to lower fill factor and open circuit voltage (VOC). The electron diffusion coefficient (Dn) and mobility (μn) of the TiO2 and Nb:TiO2 NW in the presence of iodide/triiodide ions were an order of magnitude higher compared with the undoped samples.