Hole-Phonon Relaxation and Photocatalytic Properties of Titanium Dioxide and Zinc Oxide: First-Principles Approach

Zhukov, V. P.; Tyuterev, V. G.; Chulkov, Eugene V.; Echenique, Pedro M.

doi:10.1155/2014/738921

Cited by 7 publications

(24 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The validity of the 'effective phonon' approach is well confirmed by means of comparing this data with the results of the 'exact' calculations obtained with such an approximation avoided [23,24]. We see in figure 2 that for both electrons and holes the correspondence between the results of these two approaches is almost perfect.…”

Section: Definitions and Justificationsupporting

confidence: 66%

“…According to (18) the average value of energy loss by an electron in the single electron-phonon scattering act becomes independent of the excess energy level ε av (E) = ε 0 . In our calculations [12,22,23] we have shown that for realistic band structures in ZnO and TiO 2 this quantity ε av (E) manifests a weak dependence versus E, both for electrons and holes, see figure 1. Similarly the quantity…”

Section: Definitions and Justificationmentioning

confidence: 89%

“…The extreme case would be n 0 (E) = θ (E − µ), where θ (x) is the Heaviside step Figure 2. The downfall times for electrons (a) and holes (b) in ZnO as calculated via the 'exact' method [23,24] and employing the 'effective phonon' approach.…”

Section: Strong Degeneracymentioning

confidence: 99%

“…Average loss of energy due to the emission of a phonon by carriers scattered from the excess energy level E in ZnO wurtzite (a) and TiO 2 anatase (b)[23].…”

mentioning

confidence: 99%

“…High-energy 'tails' of electron distribution in ZnO (a) and hole distribution in TiO 2 with an anatase structure (b) depending on the external excitation level E max[23]. The arrows indicate estimated positions of chemical potential (40).…”

mentioning

confidence: 99%

See 4 more Smart Citations

Relaxation of highly excited carriers in wide-gap semiconductors

Tyuterev¹,

Zhukov²,

Echenique³

et al. 2014

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The electron energy relaxation in semiconductors and insulators after high-level external excitation is analysed by a semi-classical approach based on a kinetic equation of the Boltzmann type. We show that the non-equilibrium distributions of electrons and holes have a customary Fermi-like shape with some effective temperature but also possess a high-energy non-Fermian 'tail'. The latter may extend deep into the conduction and valence bands while the Fermi-like component is localized within a small energy range just above the edge of the band gap. The effective temperature, effective chemical potential, and the shape of the high-energy component are governed by the process of electron-phonon interactions as well as by the rates of carrier generation and inter-band radiative recombination.

show abstract

Section: Definitions and Justificationsupporting

confidence: 66%

Section: Definitions and Justificationmentioning

confidence: 89%

Section: Strong Degeneracymentioning

confidence: 99%

“…Average loss of energy due to the emission of a phonon by carriers scattered from the excess energy level E in ZnO wurtzite (a) and TiO 2 anatase (b)[23].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Relaxation of highly excited carriers in wide-gap semiconductors

Tyuterev¹,

Zhukov²,

Echenique³

et al. 2014

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

Ultrafast Dynamics of Photongenerated Holes at a CH₃OH/TiO₂ Rutile Interface

Chu¹,

Saidi

Zheng³

et al. 2016

J. Am. Chem. Soc.

138

167

View full text Add to dashboard Cite

Photogenerated charge carrier dynamics near molecule/TiO interfaces are important for the photocatalytic and photovoltaic processes. To understand this fundamental aspect, we performed a time-domain ab initio nonadiabatic molecular dynamics study of the photogenerated hole dynamics at the CHOH/rutile TiO(110) interface. We studied the forward and reverse hole transfer between TiO and CHOH as well as the hole energy relaxation to the valence band maximum. First, we show that the hole-trapping ability of CHOH depends strongly on the adsorption structure. Only when the CHOH is deprotonated to form chemisorbed CHO will ∼15% of the hole be trapped by the molecule. Second, we find that strong fluctuations of the HOMO energies of the adsorbed molecules induced by electron-phonon coupling provide additional channels, which accelerate the hole energy relaxation. Third, we demonstrate that the charge transfer and energy relaxation processes depend significantly on temperature. When the temperature decreases from 100 to 30 K, the forward hole transfer and energy relaxation processes are strongly suppressed because of the reduction of phonon occupation. These results indicate that the molecule/TiO energy level alignment, thermal excitation of a phonon, and electron-phonon coupling are the key factors that determine the photogenerated hole dynamics. Our studies provide valuable insights into the photogenerated charge and energy transfer dynamics at molecule/semiconductor interfaces.

show abstract

Recent progress in magnetic iron oxide–semiconductor composite nanomaterials as promising photocatalysts

2015

View full text Add to dashboard Cite

Photocatalytic degradation of toxic organic pollutants is a challenging tasks in ecological and environmental protection. Recent research shows that the magnetic iron oxide-semiconductor composite photocatalytic system can effectively break through the bottleneck of single-component semiconductor oxides with low activity under visible light and the challenging recycling of the photocatalyst from the final products. With high reactivity in visible light, magnetic iron oxide-semiconductors can be exploited as an important magnetic recovery photocatalyst (MRP) with a bright future. On this regard, various composite structures, the charge-transfer mechanism and outstanding properties of magnetic iron oxide-semiconductor composite nanomaterials are sketched. The latest synthesis methods and recent progress in the photocatalytic applications of magnetic iron oxide-semiconductor composite nanomaterials are reviewed. The problems and challenges still need to be resolved and development strategies are discussed.

show abstract

Hole-Phonon Relaxation and Photocatalytic Properties of Titanium Dioxide and Zinc Oxide: First-Principles Approach

Cited by 7 publications

References 27 publications

Relaxation of highly excited carriers in wide-gap semiconductors

Relaxation of highly excited carriers in wide-gap semiconductors

Ultrafast Dynamics of Photongenerated Holes at a CH₃OH/TiO₂ Rutile Interface

Recent progress in magnetic iron oxide–semiconductor composite nanomaterials as promising photocatalysts

Contact Info

Product

Resources

About

Hole-Phonon Relaxation and Photocatalytic Properties of Titanium Dioxide and Zinc Oxide: First-Principles Approach

Cited by 7 publications

References 27 publications

Relaxation of highly excited carriers in wide-gap semiconductors

Relaxation of highly excited carriers in wide-gap semiconductors

Ultrafast Dynamics of Photongenerated Holes at a CH3OH/TiO2 Rutile Interface

Recent progress in magnetic iron oxide–semiconductor composite nanomaterials as promising photocatalysts

Contact Info

Product

Resources

About

Ultrafast Dynamics of Photongenerated Holes at a CH₃OH/TiO₂ Rutile Interface