The Shankar Research Group - Excitonics and Nanostructures Laboratory



33. Mohammadpour A, Waghmare PR, Mitra SK and Shankar K, Anodic Growth of Large-Diameter Multipodal TiO2 nanotubes ACS Nano 2010 4(12) 7421-30.

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Abstract: We report on the formation of a new class of nanostructures, namely, multipodal hollow titania nanotubes possessing two or more legs, achieved during the electrochemical anodization of titanium in diethylene glycol (DEG)-based electrolytes. The unique multipodal porous structure is expected to extend and enhance the applications of TiO2 nanotube arrays. Multipodal nanotubes form by a process we term “nanotube combination”, which only occurs in viscous electrolytes at high anodization potentials in the presence of a low concentration of fluoride-bearing species. The mechanism of formation of multipodal nanotubes is considered, and the tube length at which nanotube combination occurs is predicted theoretically using a simplified analytical model. The results suggest that capillary forces strong enough to bend the TiO2 nanotubes by tens of degrees are generated during the imbibition of electrolyte into and out of the intertubular spaces between adjacent tapered nanotubes.

32. Mohammadpour A and Shankar K, Anodic TiO2 nanotube arrays with optical wavelength-sized apertures Journal of Materials Chemistry, 2010 20 8474-8477.

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Abstract: We report on the fabrication and optical properties of very large diameter titanium dioxide nanotube (NT) arrays with inner diameters as large as 900 nm, which surpass the largest inner diameter reported thus far for anodically formed self-organized TiO2 NTs by a factor of 2.5.

31. Kim S, Mor GK, Paulose M, Varghese OK, Shankar K and Grimes CA, "Broad spectrum light harvesting in TiO2 nanotube array - hemicyanine dye-P3HT hybrid solid-state solar cells", IEEE Journal of Selected Topics in Quantum Electronics, 2010 16(6) 1573-1580.