Comparison of the electronic structure of anatase and rutile<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>TiO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math>single-crystal surfaces using resonant photoemission and x-ray absorption spectroscopy

Thomas, Andrew G.; Flavell, Wendy R.; Mallick, Arijit; Kumarasinghe, A.R.; Tsoutsou, D.; Khan, Nasir; Chatwin, C.; Rayner, S.; Smith, Graham C.; Stockbauer, Roger; Warren, S.; Johal, T. K.; Patel, Shelain; Holland, D.M.P.; Taleb, Abdelhafed; Wiame, Frédéric

doi:10.1103/physrevb.75.035105

Cited by 262 publications

(214 citation statements)

References 53 publications

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“…We computed excitation energies of 0.64 eV, 1.15 eV, and 0.89 eV for the (+1/0), (+2/+1), and (+2/0) transitions. Experimentally, a feature at ∼1.0-1.1 eV below the CB has been reported in different experiments (combined x-ray photoemission/absorption spectroscopy, 76 as well as scanning tunneling spectroscopy 57 ) on reduced anatase surfaces and has been attributed to O vacancies. Notice that, since the stable charge state of the O vacancy is q = +1 at room temperature, it seems likely that the (+2/+1) transition is mainly probed in optical experiments; accordingly, our computed excitation energy of 1.15 eV matches excellently with the measured spectroscopic features.…”

Section: Anatasementioning

confidence: 99%

Defect calculations in semiconductors through a dielectric-dependent hybrid DFT functional: The case of oxygen vacancies in metal oxides

Gerosa

Bottani

Caramella

et al. 2015

The Journal of Chemical Physics

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We investigate the behavior of oxygen vacancies in three different metal-oxide semiconductors\ud (rutile and anatase TiO2, monoclinic WO3, and tetragonal ZrO2) using a recently proposed hybrid\ud density-functional method in which the fraction of exact exchange is material-dependent but obtained\ud ab initio in a self-consistent scheme. In particular, we calculate charge-transition levels relative to the\ud oxygen-vacancy defect and compare computed optical and thermal excitation/emission energies with\ud the available experimental results, shedding light on the underlying excitation mechanisms and related\ud materials properties. We find that this novel approach is able to reproduce not only ground-state\ud properties and band structures of perfect bulk oxide materials but also provides results consistent\ud with the optical and electrical behavior observed in the corresponding substoichiometric defective\ud systems. C 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.493180

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Section: Anatasementioning

confidence: 99%

Defect calculations in semiconductors through a dielectric-dependent hybrid DFT functional: The case of oxygen vacancies in metal oxides

Gerosa

Bottani

Caramella

et al. 2015

The Journal of Chemical Physics

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“…On the contrary, the anatase {001} facet is known to reconstruct under UHV conditions [9], which is usually an indication of low stability and high reactivity of the clean surface. In both {101} and {001} anatase oxygen vacancies are thought to lie beneath the surface [10,11]. Furthermore, minority {001} facets, having a high density of surface undercoordinated Ti atoms, exhibit higher reactivity for the dissociative adsorption of reactant molecules, such as water, methanol and formic acid, compared to the {101} facets [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Specific Facets-Dominated Anatase TiO2: Fluorine-Mediated Synthesis and Photoactivity

2013

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Semiconductors crystal facet engineering has become an important strategy for properly tuning and optimizing both the physicochemical properties and the reactivity of photocatalysts. In this review, a concise survey of recent results obtained in the field of specific surface-oriented anatase TiO 2 crystals preparation is presented. The attention is mainly focused on the fluorine-mediated hydrothermal and/or solvothermal processes employed for the synthesis and the assembly of anatase micro/nanostructures with dominant {001} facets. Their peculiar photocatalytic properties and potential applications are also presented, with a particular focus on photocatalysis-based environmental clean up and solar energy conversion applications. Finally, the most promising results obtained in the engineering of TiO 2 anatase crystal facets obtained by employing alternative, possibly more environmentally friendly methods are critically compared.

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“…32-45͒ and have been reinvestigated more recently. [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] From the photoemission data on rutile 42,44,47,50,53,63 the electronic band gap, corresponding to the difference between the valence-band maximum ͑VBM͒ and the conduction-band minimum ͑CBM͒, has reported values of 3.3Ϯ 0.5 eV ͑Ref. 53͒ ͓ultraviolet photoemission spectroscopy ͑UPS͒ and inverse photoemission spectroscopy ͑IPES͔͒, 3.6Ϯ 0.2 eV ͑Ref.…”

Section: Introductionmentioning

confidence: 99%

Self-energy and excitonic effects in the electronic and optical properties ofTiO2crystalline phases

et al. 2010

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We present a unified ab initio study of electronic and optical properties of TiO 2 rutile and anatase phases with a combination of density-functional theory and many-body perturbation-theory techniques. The consistent treatment of exchange and correlation, with the inclusion of many-body one-particle and two-particles effects in self-energy and electron-hole interaction, produces a high-quality description of electronic and optical properties, giving, for some quantities, the first available estimation for this compound. In particular, we give a quantitative estimate of the electronic and direct optical gaps, clarifying their role with respect to previous measurements obtained by various experimental techniques. We obtain a description for both electronic gap and optical spectra that is consistent with experiments by analyzing the role of different contributions to the experimental optical gap and relating them to the level of theory used in our calculations. We also show the spatial properties of excitons in the two crystalline phases, highlighting the localization character of different optical transitions. This paper aims at understanding and firmly establishing electro-optical bulk properties, yet to be clarified, of this material of fundamental and technological interest for green energy applications.

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Comparison of the electronic structure of anatase and rutileTiO2single-crystal surfaces using resonant photoemission and x-ray absorption spectroscopy

Cited by 262 publications

References 53 publications

Defect calculations in semiconductors through a dielectric-dependent hybrid DFT functional: The case of oxygen vacancies in metal oxides

Defect calculations in semiconductors through a dielectric-dependent hybrid DFT functional: The case of oxygen vacancies in metal oxides

Specific Facets-Dominated Anatase TiO2: Fluorine-Mediated Synthesis and Photoactivity

Self-energy and excitonic effects in the electronic and optical properties ofTiO2crystalline phases

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