From Nanorods to Atomically Thin Wires of Anatase TiO₂: Nonhydrolytic Synthesis and Characterization

Abstract

A nonhydrolytic two-step chemical process has been developed to synthesize ultrathin, nearly monodisperse TiO(2) (anatase) wires with tunable diameters of 5 nm to approximately 4 A, reaching the atomic length scale. The high-quality anatase titania atomically thin wires can be doped and stabilized with nitrogen species by introducing suitable nitrogen-containing molecules. The ultrathin wires, particularly the atomically thin wires, as well as the precursor, have been thoroughly characterized by an extensive series of structural, spectroscopic, and other techniques. Possible formation mechanisms for the rods and the wires are proposed on the basis of experimental results obtained under varying reaction conditions. Also demonstrated are the pronounced effects of size and N-doping on the electronic, optical, and phononic properties of the anatase titania wires in the smallest size regime.

Enhancement of Hole Mobility of Poly(3‐hexylthiophene) Induced by Titania Nanorods in Composite Films

“…Here, composite fi lms of conjugated polymer P3HT and TiO 2 nanorods [ 24 ] modifi ed with pyridine ( Figure S1, Supporting Information) are shown to demonstrate up to three times the hole mobility of a pristine P3HT fi lm, which can be attributed to the improvement of the crystallinity of P3HT and the optimized orientation of polymer chains in the composite fi lms induced by the nanorods. Through the comparison of different types of nanoparticles, it is confi rmed that the rod-like shape and the surface modifi er (pyridine ligand) both play important roles on the crystallinity and hole mobility in the P3HT matrix.…”

Comparative optical study of colloidal anatase titania nanorods and atomically thin wires

“…The dimensions of 3 samples have been estimated based on the statistical analysis of HRTEM images of the respective samples, as has been discussed in detail in ref. 15. All optical absorption measurements were performed on highly diluted solutions of TiO 2 nanorods/nanowires in the same solvent chloroform without any sign of aggregation which may be accounting for undesirable scattering effects.…”

“…At the same time, the manifestation of the size quantization effect inuencing the photophysical properties of colloidal anatase TiO 2 nanoparticles has remained controversial over decades. 16,20 Taking advantage of the availability of the colloidal anatase TiO 2 nanorods with a diameter systematically decreasing towards the dimensions of extremely thin atomic wires, which can be synthesized within one and the same nonhydrolytic solution approach by variation of the reaction time, 15 we have conducted a systematic study of their optical absorption as well as steady-state and time-resolved PL, with the results presented and discussed here. …”

Large-surface mesoporous TiO2 nanoparticles: Synthesis, growth and photocatalytic performance

“…As one of the most promising semiconducting materials, titanium dioxide (TiO 2 ) has acquired much more attention because of its diverse applications in bioanalysis [4], photocatalysis [5,6], sensors [7,8], pigments, cosmetics [9], and energy convertors (e.g., Lithium ionic batteries [10], and dye-sensitized solar cells [11]). …”