Bulk and surface electron states in WO<sub>3</sub>and tungsten bronzes

Bullett, D.W.

doi:10.1088/0022-3719/16/11/022

Cited by 138 publications

(108 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Bearing in mind that the charge density plots consider only the valence electrons, the fact that we observe some charge on the hydrogen atom but not on any of the others indicates that hydrogen is not ionised. That larger atoms are completely ionised is consistent with other reported experimental results [28]. It is interesting that the same phenomenon occurs in both the cubic and hexagonal cases.…”

Section: Charge Densitysupporting

confidence: 92%

“…These are given in Figure 8. These results agree extremely well with the calculated band structures of both Bullett [28] and Cora et. al.…”

Section: Density Of Statessupporting

confidence: 87%

“…This is the case in both the cubic and hexagonal systems. An older paper by D.W. Bullet [28], utilising a non-relativistic atomic orbital-based method shows a very similar band structure (oxygen 2p as valence band and tungsten 5d as conduction band). Figure 7 shows a comparison of the density of states of the cubic bronzes with the parent oxide.…”

Section: Density Of Statesmentioning

confidence: 99%

“…Once again, analysis of the individual atomic contributions to the density of states indicates that each sodium atom is fully ionised, and the electron donated to the tungsten 5d conduction band [28].…”

Section: Cubic Sodium Tungsten Bronze Seriesmentioning

confidence: 99%

See 3 more Smart Citations

Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

Ingham

Hendy

Chong³

et al. 2005

Phys. Rev. B

119

View full text Add to dashboard Cite

Tungsten trioxide adopts a variety of structures which can be intercalated with charged species to alter the electronic properties, thus forming 'tungsten bronzes'. Similar optical effects are observed upon removing oxygen from WO3, although the electronic properties are slightly different. Here we present a computational study of cubic and hexagonal alkali bronzes and examine the effects on cell size and band structure as the size of the intercalated ion is increased. With the exception of hydrogen (which is predicted to be unstable as an intercalate), the behaviour of the bronzes are relatively consistent. NaWO3 is the most stable of the cubic systems, although in the hexagonal system the larger ions are more stable. The band structures are identical, with the intercalated atom donating its single electron to the tungsten 5d valence band. Next, this was extended to a study of fractional doping in the NaxWO3 system (0 ≤ x ≤ 1). A linear variation in cell parameter, and a systematic change in the position of the Fermi level up into the valence band was observed with increasing x. In the underdoped WO3−x system however, the Fermi level undergoes a sudden jump into the conduction band at around x = 0.2. Lastly, three compounds of a layered WO4 · α,ω-diaminoalkane hybrid series were studied and found to be insulating, with features in the band structure similar to those of the parent WO3 compound which relate well to experimental UVvisible spectroscopy results.

show abstract

Section: Charge Densitysupporting

confidence: 92%

“…These are given in Figure 8. These results agree extremely well with the calculated band structures of both Bullett [28] and Cora et. al.…”

Section: Density Of Statessupporting

confidence: 87%

Section: Density Of Statesmentioning

confidence: 99%

Section: Cubic Sodium Tungsten Bronze Seriesmentioning

confidence: 99%

See 2 more Smart Citations

Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

Ingham

Hendy

Chong³

et al. 2005

Phys. Rev. B

119

View full text Add to dashboard Cite

show abstract

“…Synthesis typically yields sub-stoichiometric tungsten oxide WO 3-δ with metal conductivity and blue color from oxygen vacancies and requires subsequent oxidative treatment. These vacancies constitute electronic defect states which are visible as up to six convoluted peaks near the Fermi energy in valence band XPS or PES spectra [13][14][15]. WO 3-δ with metal conductivity cannot produce the necessary electron hole pairs for solar energy conversion.…”

Section: Surface and Sub-surface Studies On Tungsten And Iron Oxide Pmentioning

confidence: 99%

Between photocatalysis and photosynthesis: Synchrotron spectroscopy methods on molecules and materials for solar hydrogen generation

Bora

Thieß

et al. 2013

Journal of Electron Spectroscopy and Related Phenomena

View full text Add to dashboard Cite

Energy research is to a large extent materials research, encompassing the physics and chemistry of materials, including their synthesis, processing towards components and design towards architectures, allowing for their functionality as energy devices, extending towards their operation parameters and environment, including also their degradation, limited life, ultimate failure and potential recycling. In all these stages, xray and electron spectroscopy are helpful methods for analysis, characterization and diagnostics for the engineer and for the researcher working in basic science. This paper gives a short overview of experiments with x-ray and electron spectroscopy for solar energy and water splitting materials and addresses also the issue of solar fuel, a relatively new topic in energy research. The featured systems are iron oxide and tungsten oxide as photoanodes, and hydrogenases as molecular systems. We present surface and sub-surface studies with ambient pressure XPS and hard x-ray XPS, resonant photoemission, light induced effects in resonant photoemission experiments and a photo-electrochemical in-situ/operando experiment, and nuclear resonant vibrational spectroscopy (NRVS).

show abstract

Semiempirical calculations on WO ₃ and M _X WO ₃ crystals (M = H, Li, Na)

Stashans

Lunell

1997

Int J of Quantum Chemistry

View full text Add to dashboard Cite

ABSTRACT:The monoclinic structure of tungsten trioxide WO has been studied by 3 Ž . combining a modified intermediate neglect of differential overlap INDO method and the supercell model. The fitted semiempirical parameters describe very well the features of the band structure and crystal structure. Calculations of H, Li, and Na impurities in a WO crystal have been performed to study the absorption spectra and the equilibrium 3 geometries of intercalated impurities.

show abstract

Bulk and surface electron states in WO₃and tungsten bronzes

Cited by 138 publications

References 62 publications

Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

Between photocatalysis and photosynthesis: Synchrotron spectroscopy methods on molecules and materials for solar hydrogen generation

Semiempirical calculations on WO ₃ and M _X WO ₃ crystals (M = H, Li, Na)

Contact Info

Product

Resources

About

Bulk and surface electron states in WO3and tungsten bronzes

Cited by 138 publications

References 62 publications

Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

Between photocatalysis and photosynthesis: Synchrotron spectroscopy methods on molecules and materials for solar hydrogen generation

Semiempirical calculations on WO 3 and M X WO 3 crystals (M = H, Li, Na)

Contact Info

Product

Resources

About

Bulk and surface electron states in WO₃and tungsten bronzes

Semiempirical calculations on WO ₃ and M _X WO ₃ crystals (M = H, Li, Na)