First-principles study of thinTiOxand bulklike rutile nanowires

Abstract

We have systematically investigated structural, electronic and magnetic properties of very thin TiO x ͑x =1,2͒ nanowires as well as bulklike ͑110͒ rutile nanowires by using the first-principles plane-wave pseudopotential calculations based on density functional theory. A large number of different possible structures have been searched via total-energy calculations in order to find the ground-state structures of these nanowires. Three-dimensional structures are more energetically stable than planar ones for both of the stoichiometries ͑i.e., x =1,2͒. The stability of TiO x nanowires is enhanced with its increasing radius as a result of reaching sufficient coordination number of Ti and O atoms. All stoichiometric TiO 2 nanowires studied exhibit semiconducting behavior and have nonmagnetic ground state. There is a correlation between binding energy ͑E b ͒ and energy band gap ͑E g ͒ of TiO 2 nanowires. In general, E b increases with increasing E g . In TiO nanowires, both metallic and semiconductor nanowires result. In this case, in addition to paramagnetic TiO nanowires, there are also ferromagnetic ones. We have also studied the structural and electronic properties of bulklike rutile ͑110͒ nanowires. There is a crossover in terms of energetics, and bulklike nanowires are more stable than the thin nanowires for larger radius wires after a critical diameter. These ͑110͒ rutile nanowires are all semiconductors.

Electronic structures and optical spectra of thin anataseTiO2nanowires through hybrid density functional and quasiparticle calculations

“…Nanometer-sized materials come into view with preferable and interesting physical and chemical properties [21][22][23]. For instance, quasi-one-dimensional periodic structures facilitate the transport of the charge carriers.…”

Yolk@shell anatase TiO2 hierarchical microspheres with exposed {001} facets for high-performance dye sensitized solar cells

“…The comparatively more dye molecules adsorption is thus expected to occur on {001} facets, which is 65 also supported by theoretical and experimental results. [19][20][21] Moreover, the band edges of anatase TiO 2 {001} facets are more negative than {101} facets. 22 However, to the best of our knowledge, most of these anatase TiO 2 exposed by {001} facets used in DSSCs are 2D sheetlike nanocrystals or microspheres 70 closely packed by micro/submicro-sized anatase TiO 2 nanosheets (TiO 2 NSs).…”

DFT studies of CNT–functionalized uracil-acetate hybrids

“…Moreover, other nano-based structures with typical characters have been introduced through the attempts of so many researchers in the following years [3,4]. Besides the known importance of individual nano-based structures, their hybridizations with other structures have been viewed important for various types of applications [5,6].…”