Local atomic and electronic arrangements in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">W</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="normal">x</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">V</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mi mathvariant="normal">−</mml:mi>

Tang, Christopher; Georgopoulos, P.; Fine, M. E.; Cohen, J. B.; Nygren, Mats; Knapp, G. S.; Aldred, A. T.

doi:10.1103/physrevb.31.1000

Cited by 160 publications

(109 citation statements)

References 38 publications

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“…The work of Goodenough has been further confirmed by Tang et al [32] who investigated the oxidation states of vanadium and tungsten in W 0.05 V 0.95 O 2 and W 0.08 V 0.92 O 2 by EXAFS and magnetic susceptibility studies. They suggest the formation of V 3+ -W 6+ and V 3+ -V 4+ pairs in vanadium (IV) oxide with tungsten doping, in accordance with Goodenough"s theories on the stability of the anti-ferroelectric distortion.…”

Section: Tc Coatingsupporting

confidence: 52%

Thermochromic Coatings for Intelligent Architectural Glazing

Parkin

Binions

Piccirillo

et al. 2008

JNanoR

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Abstract. Thermochromic glazing is a type of intelligent glazing; one where the properties of the glazing change according to some external stimulus. More particularly a thermochromic window is a device that changes its transmission and reflectance properties at a critical temperature (T c ). At this specific temperature the material undergoes a semi-conductor to metal transition. At temperatures lower than T c the window lets all of the solar energy that hits it through. At temperatures above T c the window reflects the infra-red portion of solar energy. In such a way thermochromic windows may help reduce air conditioning and heating costs leading to more energy efficient buildings. This review details the nature of the semi-conductor to metal transition and indicates how substitutional doping within a crystal lattice can be used to manipulate and fine tune the critical temperature. Also detailed is the underlying science and methodologies so far employed in the production of thermochromic thin films.

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Section: Tc Coatingsupporting

confidence: 52%

Thermochromic Coatings for Intelligent Architectural Glazing

Parkin

Binions

Piccirillo

et al. 2008

JNanoR

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“…From the calculated substitution energies, 2.344 and 1.963 eV for the low-and hightemperature phases respectively, we can estimate the change in the critical temperature upon doping, 12) where T c is the critical temperature of the pure phase, dH is the change in enthalpy (internal or lattice energy) of the pure phases and n is the fraction of substituted sites; see Netsianda et al (2008) for a derivation of equation (2.12). For a 1 per cent solution of W we predict a reduction of 48.4 K, whereas it is observed to be a reduction of 26 K (Tang et al 1985).…”

Section: (Iv) Tuning the Critical Temperature Of Vanadium Dioxide Witmentioning

confidence: 62%

Advances in computational studies of energy materials

Catlow

Guo

Miskufova

et al. 2010

Phil. Trans. R. Soc. A.

127

145

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We review recent developments and applications of computational modelling techniques in the field of materials for energy technologies including hydrogen production and storage, energy storage and conversion, and light absorption and emission. In addition, we present new work on an Sn 2 TiO 4 photocatalyst containing an Sn(II) lone pair, new interatomic potential models for SrTiO 3 and GaN, an exploration of defects in the kesterite/stannite-structured solar cell absorber Cu 2 ZnSnS 4 , and report details of the incorporation of hydrogen into Ag 2 O and Cu 2 O. Special attention is paid to the modelling of nanostructured systems, including ceria (CeO 2 , mixed Ce x O y and Ce 2 O 3 ) and group 13 sesquioxides. We consider applications based on both interatomic potential and electronic structure methodologies; and we illustrate the increasingly quantitative and predictive nature of modelling in this field.

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“…A few S measurements of undoped VO 2 have been reported [12][13][14][15], but there has been no report on electron-doped VO 2 . Chemical substitution of VO 2 with aliovalent ions of W 6+ is a classical way to effectively dope electrons [16] and reduce the T MI [17]. Abrupt changes in the S values accompanied by MI transition were observed for all films and the transition temperature of S decreased with x in good linear relation with T MI .…”

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confidence: 90%

Thermopower analysis of the electronic structure around the metal-insulator transition inV1−xWxO2

2014

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The electronic structure across the metal-insulator (MI) transition of electron-doped V 1−x W x O 2 epitaxial films (x = 0−0.06) grown on α-Al 2 O 3 substrates was studied by means of thermopower (S) measurements. Significant increase of |S| values accompanied by MI transition was observed, and the transition temperatures of S (T S ) decreased with x in a good linear relation with MI transition temperatures. |S| values of V 1−x W x O 2 films at T > T S were constant at low values of 23 μV K −1 independently of x, which reflects a metallic electronic structure, whereas those at T < T S almost linearly decreased with logarithmic W concentrations. Vanadium dioxide (VO 2 ) has attracted considerable attention due to its ability to reversibly transform from a lowtemperature insulator into a high-temperature metal at ß340 K [1]. The metal-insulator (MI) transition is accompanied by a structural change from monoclinic to tetragonal-type rutile structure. The transformation of crystal structure originates from dimerization of vanadium ions with accompanying the position shifting from linear chains along c axis of rutile phase to zigzag type, resulting in a monoclinic structure. The structural change causes reconstruction of electronic structures to open up a charge gap of ß0.6 eV that abruptly changes both the electrical resistivity and infrared transmission [2]. These features of the MI transition for VO 2 appear promising for potential applications to electrical and optical switching devices, operating at room temperature (RT). Recently, reversible alternation of electronic properties from insulator to metal state was demonstrated by both electrostatic charge doping [3] and hydrogenation [4], which enables on-demand-tunable devices using the MI transition of VO 2 .However, the driving mechanism of the MI transition in VO 2 is still not fully understood, i.e., it has been debated that the MI transition should be regarded as either a structurally driven Peierls transition with electron-phonon interaction or a Mott transition with strong electron-electron correlation [5]. Thus, intensive efforts have been devoted to experimentally observe electronic structure change of VO 2 across the MI transition mainly by spectroscopic techniques, such as x-ray photoemission spectroscopy (PES) [6] and angle resolved PES [7] for valence band structure observation, as well as x-ray absorption spectroscopy [8] for the conduction band structure, but the mechanism of the MI transition is still unclear. Further investigation on the electronic-structure evolution by another experimental means is inevitable for the elucidation of MI transition, which should give crucial information for fundamental physics as well as for practical device application of VO 2 .Here we focused on thermopower (S) as a physical property to investigate the electronic structure across the MI transition, because S values should be sensitive to significant changes in * Corresponding author: hiromichi.ohta@es.hokudai.ac.jp the electronic structure of VO 2 at T MI . In g...

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Local atomic and electronic arrangements inWxV1−

Cited by 160 publications

References 38 publications

Thermochromic Coatings for Intelligent Architectural Glazing

Thermochromic Coatings for Intelligent Architectural Glazing

Advances in computational studies of energy materials

Thermopower analysis of the electronic structure around the metal-insulator transition inV1−xWxO2

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