Formation of Anisotropic Nanostructures on Rutile TiO2(110) Surfaces and Their Photo-Absorption Properties

Solanki, Vanaraj; Joshi, Shalik Ram; Mishra, Indrani; Kanjilal, D.; Varma, Shikha

doi:10.1007/s11661-018-4622-3

Cited by 7 publications

(2 citation statements)

References 36 publications

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“…Slowing the propagation may be viewed as a trap, because an activation barrier needs to be crossed, yet it may also result in increased recombination with holes on the adjacent oxygen atoms. The activation energies of anisotropic charge propagation in oxides have been computed and show that it can vary significantly. − Scheme E presents charge propagation close to an interstitial Ti cation. The charge of an interstitial Ti (Ti int . )…”

Section: Methodsmentioning

confidence: 99%

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO₂ Single Crystal. Possible Anisotropic Propagation

Alamoudi,

Katsiev,

Idriss

2023

J. Phys. Chem. Lett.

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Defects (oxygen vacancies and interstitial cations) in oxide semiconductors have recently been invoked as a key property behind increased photocatalytic reaction rates. In this work, we have monitored by transient absorption spectroscopy (TAS) excited electrons in the conduction band decaying into the invoked traps to extract their lifetime using a rutile single crystal instead of the more conveniently used powder homologue. This is preferred in order to rule out grain boundary, degree of crystallinity, and size effects among other parameters that would obscure the results. It was found, in the energy region investigated (1.3−1.8 eV), that the lifetime of excited electrons is about four times shorter for the bulk defect crystal when compared to the fresh one. This indicates that the created defects (mostly oxygen defects and interstitial Ti cations) are unlikely to contribute to reaction rate enhancement.

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Section: Methodsmentioning

confidence: 99%

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO₂ Single Crystal. Possible Anisotropic Propagation

Alamoudi,

Katsiev,

Idriss

2023

J. Phys. Chem. Lett.

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“…Anisotropy of charge diffusion has been recognized early on for rutile TiO 2 (110). , It was observed that the conductivity was 3–6 times higher along the [001] direction when compared to that along the [11̅0] direction. It has also been observed that Ar ion sputtering causes anisotropy of Ti–O species along the [001] direction irrespective of the azimuth of sputtering.…”

Section: Introductionmentioning

confidence: 99%

Direct Visualization of a Gold Nanoparticle Electron Trapping Effect

et al. 2022

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A new atomic-scale anisotropy in the photoreaction of surface carboxylates on rutile TiO2(110) induced by gold clusters is found. STM and DFT+U are used to study this phenomenon by monitoring the photoreaction of a prototype hole-scavenger molecule, benzoic acid, over stoichiometric (s) s-TiO2, Au9/s-TiO2, and reduced (r) Au9/r-TiO2. STM results show that benzoic acid adsorption displaces a large fraction of Au clusters from the terraces toward their edges. DFT calculations explain that Au9 clusters on stoichiometric TiO2 are distorted by benzoic acid adsorption. The influence of sub-monolayers of Au on the UV/visible photoreaction of benzoic acid was explored at room temperature, with adsorbate depletion taken as a measure of activity. The empty sites, observed upon photoexcitation, occurred in elongated chains (2 to 6 molecules long) in the [11̅0] and [001] directions. A roughly 3-fold higher depletion rate is observed in the [001] direction. This is linked to the anisotropic conduction of excited electrons along [001], with subsequent trapping by Au clusters leaving a higher concentration of holes and thus an increased decomposition rate. To our knowledge this is the first time that atomic-scale directionality of a chemical reaction is reported upon photoexcitation of the semiconductor.

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Energy dependence of morphologies on photoresist surfaces under Ar+ ion bombardment with normal incidence

Yang

Hirsch

et al. 2020

Applied Surface Science

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Formation of Anisotropic Nanostructures on Rutile TiO2(110) Surfaces and Their Photo-Absorption Properties

Cited by 7 publications

References 36 publications

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO₂ Single Crystal. Possible Anisotropic Propagation

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO₂ Single Crystal. Possible Anisotropic Propagation

Direct Visualization of a Gold Nanoparticle Electron Trapping Effect

Energy dependence of morphologies on photoresist surfaces under Ar+ ion bombardment with normal incidence

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Formation of Anisotropic Nanostructures on Rutile TiO2(110) Surfaces and Their Photo-Absorption Properties

Cited by 7 publications

References 36 publications

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO2 Single Crystal. Possible Anisotropic Propagation

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO2 Single Crystal. Possible Anisotropic Propagation

Direct Visualization of a Gold Nanoparticle Electron Trapping Effect

Energy dependence of morphologies on photoresist surfaces under Ar+ ion bombardment with normal incidence

Contact Info

Product

Resources

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Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO₂ Single Crystal. Possible Anisotropic Propagation

Monitoring the Lifetime of Photoexcited Electrons in a Fresh and Bulk Reduced Rutile TiO₂ Single Crystal. Possible Anisotropic Propagation