Femtosecond Investigation of Electron Trapping in Semiconductor Nanoclusters

Skinner, David; Colombo, D.; Cavaleri, Joseph J.; Bowman, R. M.

doi:10.1021/j100020a003

Cited by 236 publications

(223 citation statements)

References 2 publications

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“…Bowman and coworkers first reported pump-probe diffuse-reflectance spectroscopic measurements of heterogeneous photocatalytic reactions [4][5][6][7]. Decay kinetics of electrons trapped in levels located below the CB bottom (electron trap = ET) or electrons in the CB after photoexcitation by femtosecond ultraviolet pump pulses was observed in the picosecond time region and analyzed.…”

Section: Direct Observation Of Electron-hole Recombinationmentioning

confidence: 99%

Titania Photocatalysis beyond Recombination: A Critical Review

2013

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Section: Direct Observation Of Electron-hole Recombinationmentioning

confidence: 99%

Titania Photocatalysis beyond Recombination: A Critical Review

2013

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“…Free electrons excited in the conduction band are trapped in midgap states within picoseconds. 33 A finite fraction of the trapped electrons are thermally excited to the conduction band. Conduction-band electrons give absorption characterized by a monotonous spectrum formulated by ν -1.5 , when the momentum required for the intraband transition is provided by acoustic phonons.…”

Section: Electronic States Of the Sensitized Catalystsmentioning

confidence: 99%

Photoinduced Dynamics of TiO₂ Doped with Cr and Sb

et al. 2008

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Rutile particles doped by Cr and Sb with Sb/Cr ratios greater than unity were active for photocatalytic O 2 evolution from an aqueous silver nitrate solution under visible light irradiation. Two vibrational bands appeared in Raman scattering resonant to the electronic absorption and were assigned to symmetric breathing modes of the CrO 6 octahedron and neighboring TiO 6 octahedra, on the assumption that Cr dopant atoms exactly replaced Ti cations in rutile. Electrons excited with 355-nm and 532-nm light pulses showed absorption of mid-IR light, which was traced as a function of the time delay in a microsecond domain. By optimizing the Sb/Cr ratio, electron-hole recombination was retarded compared with that in non-doped rutile. Chromium dopants when accompanied with antimony dopants are proposed to trap the charge carriers without much enhancement of the recombination. The optimized Sb/Cr ratios were common for both the visible lightinduced O 2 production and the retarded recombination, suggesting that the charge carriers of the retarded recombination are used to produce O 2 .

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“…15 Unfortunately, these methods affect not only surface properties, but also size, shape, and crystallinity of nanoparticles. Several low-temperature techniques for synthesizing TiO 2 nanoparticles have been developed using the following approaches: sol-gel methods, 22 formation from Ti-alkoxide precursors in aqueous 23 or organic media, 24 TiCl 4 hydrolysis at low temperature, 25 and a non-hydrolytic combination of Ti-alkoxide and TiCl 4 . 26 However, these methods have given rise to issues such as controlling the reaction rates which lead to the loss of microstructural control 22 and obtaining nanoparticles which are not soluble in organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Controlling Surface Defects and Photophysics in TiO₂ Nanoparticles

et al. 2014

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Titanium dioxide (TiO 2 ) is widely used for photocatalysis and solar cell applications, and the electronic structure of bulk TiO 2 is well understood. However, surface structure of nanoparticulate TiO 2 , which has a key role in properties such as solubility and catalytic activity, still remains controversial. Detailed understanding of surface defects structures may help explain reactivity and overall materials performance in a wide range of applications. In this work we address the solubility problem and surface defects control on TiO 2 nanoparticles. We report the synthesis and characterization of ~ 4 nm TiO 2 anatase spherical nanoparticles that are soluble and stable in a wide range of organic solvents and water. By controlling the temperature during the synthesis, we are able to tailor the density of defect states on the surface of the TiO 2 nanoparticles without affecting parameters such as size, shape, core crystallinity and solubility.The morphology of both kinds of nanoparticles was determined by TEM. EPR experiments were used to characterize the surface defects, and transient absorption measurements demonstrate the influence of the TiO 2 defect states on photoinduced electron transfer dynamics.3

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Femtosecond Investigation of Electron Trapping in Semiconductor Nanoclusters

Cited by 236 publications

References 2 publications

Titania Photocatalysis beyond Recombination: A Critical Review

Titania Photocatalysis beyond Recombination: A Critical Review

Photoinduced Dynamics of TiO₂ Doped with Cr and Sb

Controlling Surface Defects and Photophysics in TiO₂ Nanoparticles

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Femtosecond Investigation of Electron Trapping in Semiconductor Nanoclusters

Cited by 236 publications

References 2 publications

Titania Photocatalysis beyond Recombination: A Critical Review

Titania Photocatalysis beyond Recombination: A Critical Review

Photoinduced Dynamics of TiO2 Doped with Cr and Sb

Controlling Surface Defects and Photophysics in TiO2 Nanoparticles

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Product

Resources

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Photoinduced Dynamics of TiO₂ Doped with Cr and Sb

Controlling Surface Defects and Photophysics in TiO₂ Nanoparticles