Defect states in W<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>studied with photoelectron spectroscopy

We investigate band gaps, equilibrium structures, and phase stabilities of several bulk polymorphs of wide-gap oxide semiconductors ZnO, TiO 2 , ZrO 2 , and WO 3 . We are particularly concerned with assessing the performance of hybrid functionals built with the fraction of Hartree-Fock exact exchange obtained from the computed electronic dielectric constant of the material. We provide comparison with more standard density-functional theory and GW methods. We finally analyze the chemical reduction of TiO 2 into Ti 2 O 3 , involving a change in oxide stoichiometry. We show that the dielectric-dependent hybrid functional is generally good at reproducing both ground-state (lattice constants, phase stability sequences, and reaction energies) and excited-state (photoemission gaps) properties within a single, fully ab initio framework.

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“…Instead, absorption measurements [92][93][94] have shown large data dispersion, with an optical band gap spanning the range 2.6-3.2 eV.…”

Section: Experimental Datamentioning

confidence: 99%

Electronic structure and phase stability of oxide semiconductors: Performance of dielectric-dependent hybrid functional DFT, benchmarked againstGWband structure calculations and experiments

et al. 2015

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“…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

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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).

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“…Salje et al [22] 3 . On the other hand, Bringans et al [12,23], studying the effect of H + bombardment on WO 3 by the ultraviolet photoemission spectroscopy, postulated that a loss of oxygen atoms from the surface rather than formation of H x WO 3 was the paramount effect.…”

mentioning

confidence: 99%

Surface morphology and deuterium retention in tungsten oxide layers exposed to low-energy, high flux D plasma

Alimov

Tyburska

Balden

et al. 2011

Journal of Nuclear Materials

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Defect states in WO3studied with photoelectron spectroscopy

Cited by 102 publications

References 33 publications

Electronic structure and phase stability of oxide semiconductors: Performance of dielectric-dependent hybrid functional DFT, benchmarked againstGWband structure calculations and experiments

Electronic structure and phase stability of oxide semiconductors: Performance of dielectric-dependent hybrid functional DFT, benchmarked againstGWband structure calculations and experiments

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

Surface morphology and deuterium retention in tungsten oxide layers exposed to low-energy, high flux D plasma

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