Charge carrier dynamics in TiO2 nanoparticles at various temperatures

Savenije, Tom J.; Huijser, Annemarie; Vermeulen, M. J. W.; Katoh, Ryuzi

doi:10.1016/j.cplett.2008.06.078

Cited by 44 publications

(49 citation statements)

References 32 publications

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“…This behavior has also been reported elsewhere, [17,39,45,46] and it has been attributed to the competition between electron trap filling and higher-order recombination. At such, it has been used as a signature for the presence of trap states in semiconductors (i.e., trap-assisted recombination).…”

Section: Resultsmentioning

confidence: 54%

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Jang

Friedrich

Müller

et al. 2017

Advanced Energy Materials

122

164

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Widespread application of solar water splitting for energy conversion is largely dependent on the progress in developing not only efficient, but also cheap and scalable photoelectrodes. Metal oxides, which can be deposited with scalable techniques and are relatively cheap, are particularly interesting, but high efficiency is still hindered by the poor carrier transport properties (i.e., carrier mobility and lifetime). In this paper, a mild hydrogen treatment is introduced to bismuth vanadate (BiVO4), which is one of the most promising metal oxide photoelectrodes, as a method to overcome the carrier transport limitations. Timeresolved microwave and terahertz conductivity measurements reveal more than two-fold enhancement of the carrier lifetime for the hydrogen-treated BiVO4, without significantly affecting the carrier mobility. This is in contrast to the case of tungsten-doped BiVO4, although hydrogen is also shown to be a donor type dopant in BiVO4. The enhancement in carrier lifetime is found to be caused by significant reduction of trap-assisted recombination, either via passivation of deep trap states or reduction of trap state density, which can be related to vanadium anti-site on bismuth or vanadium interstitials according to density functional theory calculations. Overall, these findings provide further insights on the interplay between defect modulation and carrier transport in metal oxide photoelectrodes, which will benefit the development of low-cost, highly-efficient solar energy conversion devices.

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Section: Resultsmentioning

confidence: 54%

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Jang

Friedrich

Müller

et al. 2017

Advanced Energy Materials

122

164

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“…This conductance is significantly suppressed upon lowering the temperature to 153 K, in clear contrast to pure TiO 2 , with mobilities in the range of 1 cm 2 V À1 s À1 nearly independent of temperature. 25,26 This difference suggests thermally activated hopping as the main mechanism for the charge transport due to the isolation of the Ti clusters by the organic linkers in the MOF. 27 Indeed, such clusters are too far apart to fulfil the Mott transition conditions, being approximately 4 Bohr radii.…”

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confidence: 99%

Enhancing optical absorption of metal–organic frameworks for improved visible light photocatalysis

et al. 2013

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NH2-MIL-125(Ti) has been post-synthetically functionalized with dye-like molecular fragments. The new material (methyl red-MIL-125(Ti)) exhibits improved light absorption over a wide range of the visible spectrum, and shows enhanced photocatalytic oxidation activity under visible light illumination. The consequences of functionalization and the bottlenecks in MOF photochemistry are studied in detail.

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“…21 The decay profiles are similar to each other, except for the profile for ST01, in which the signal decays quickly. Although there are no clear explanations for the fast decay of the ST01 profile, one possible explanation is that electrons are trapped by structural defects in the particles.…”

Section: Decay Profile Of Trmc Signalmentioning

confidence: 69%

Time-resolved microwave conductivity study of charge carrier dynamics in commercially available TiO₂ photocatalysts

Nakajima

Katoh

2015

J. Mater. Chem. A

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Charge carrier dynamics in various commercially available TiO 2 photocatalysts was studied by means of the time-resolved microwave conductivity (TRMC) technique. The intensities of the TRMC signals strongly depended on the photocatalyst, suggesting that the TRMC technique is potentially useful for characterizing photocatalytic activity. We found that fast charge recombination within the time resolution of the measurement system becomes dominant when one or more charges are generated primarily in a particle. We also found that the TRMC signals were sensitive to the particle size and that the maximum signal intensity was roughly proportional to the diameter of the particles. This tendency was explained on the basis of a model in which electron traps are located at the surface of the particles. P25, one of the best photocatalysts developed to date, showed a slight deviation from this tendency; the reason for the deviation is discussed.

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Charge carrier dynamics in TiO2 nanoparticles at various temperatures

Cited by 44 publications

References 32 publications

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Enhancing optical absorption of metal–organic frameworks for improved visible light photocatalysis

Time-resolved microwave conductivity study of charge carrier dynamics in commercially available TiO₂ photocatalysts

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Charge carrier dynamics in TiO2 nanoparticles at various temperatures

Cited by 44 publications

References 32 publications

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Enhancing Charge Carrier Lifetime in Metal Oxide Photoelectrodes through Mild Hydrogen Treatment

Enhancing optical absorption of metal–organic frameworks for improved visible light photocatalysis

Time-resolved microwave conductivity study of charge carrier dynamics in commercially available TiO2 photocatalysts

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Product

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Time-resolved microwave conductivity study of charge carrier dynamics in commercially available TiO₂ photocatalysts