Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films

Mesoporous films and electrodes were prepared from aqueous slurries of isolated anatase TiO2 nanoparticles. The resulting layers were annealed in air at temperatures 100°C ≤ T ≤ 450°C upon preservation of internal surface area, crystallite size and particle size. The impact of processing temperature...

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Autores principales:	Karin Rettenmaier, Thomas Berger
Formato:	article
Lenguaje:	EN
Publicado:	Frontiers Media S.A. 2021
Materias:	nanoparticle films grain boundaries deep traps charge separation recombination conductivity Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/65716a70d65f4756b68a087f3ec0f42f
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spelling	oai:doaj.org-article:65716a70d65f4756b68a087f3ec0f42f2021-11-09T17:43:25ZImpact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films2296-264610.3389/fchem.2021.772116https://doaj.org/article/65716a70d65f4756b68a087f3ec0f42f2021-11-01T00:00:00Zhttps://www.frontiersin.org/articles/10.3389/fchem.2021.772116/fullhttps://doaj.org/toc/2296-2646Mesoporous films and electrodes were prepared from aqueous slurries of isolated anatase TiO2 nanoparticles. The resulting layers were annealed in air at temperatures 100°C ≤ T ≤ 450°C upon preservation of internal surface area, crystallite size and particle size. The impact of processing temperature on charge separation efficiency in nanoparticle electrodes was tracked via photocurrent measurements in the presence of methanol as a hole acceptor. Thermal annealing leads to an increase of the saturated photocurrent and thus of the charge separation efficiency at positive potentials. Furthermore, a shift of capacitive peaks in the cyclic voltammograms of the nanoparticle electrodes points to the modification of the energy of deep traps. Population of these traps triggers recombination possibly due to the action of local electrostatic fields attracting photogenerated holes. Consequently, photocurrents saturate at potentials, at which deep traps are mostly depopulated. Charge separation efficiency was furthermore investigated for nanoparticle films and was tracked via the decomposition of hydrogen peroxide. Our observations evidence an increase of charge separation efficiency upon thermal annealing. The effect of particle consolidation, which we associate with minute atomic rearrangements at particle/particle contacts, is attributed to the energetic modification of deep traps and corresponding modifications of charge transport and recombination, respectively.Karin RettenmaierThomas BergerFrontiers Media S.A.articlenanoparticle filmsgrain boundariesdeep trapscharge separationrecombinationconductivityChemistryQD1-999ENFrontiers in Chemistry, Vol 9 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	nanoparticle films grain boundaries deep traps charge separation recombination conductivity Chemistry QD1-999
spellingShingle	nanoparticle films grain boundaries deep traps charge separation recombination conductivity Chemistry QD1-999 Karin Rettenmaier Thomas Berger Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films
description	Mesoporous films and electrodes were prepared from aqueous slurries of isolated anatase TiO2 nanoparticles. The resulting layers were annealed in air at temperatures 100°C ≤ T ≤ 450°C upon preservation of internal surface area, crystallite size and particle size. The impact of processing temperature on charge separation efficiency in nanoparticle electrodes was tracked via photocurrent measurements in the presence of methanol as a hole acceptor. Thermal annealing leads to an increase of the saturated photocurrent and thus of the charge separation efficiency at positive potentials. Furthermore, a shift of capacitive peaks in the cyclic voltammograms of the nanoparticle electrodes points to the modification of the energy of deep traps. Population of these traps triggers recombination possibly due to the action of local electrostatic fields attracting photogenerated holes. Consequently, photocurrents saturate at potentials, at which deep traps are mostly depopulated. Charge separation efficiency was furthermore investigated for nanoparticle films and was tracked via the decomposition of hydrogen peroxide. Our observations evidence an increase of charge separation efficiency upon thermal annealing. The effect of particle consolidation, which we associate with minute atomic rearrangements at particle/particle contacts, is attributed to the energetic modification of deep traps and corresponding modifications of charge transport and recombination, respectively.
format	article
author	Karin Rettenmaier Thomas Berger
author_facet	Karin Rettenmaier Thomas Berger
author_sort	Karin Rettenmaier
title	Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films
title_short	Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films
title_full	Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films
title_fullStr	Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films
title_full_unstemmed	Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films
title_sort	impact of nanoparticle consolidation on charge separation efficiency in anatase tio2 films
publisher	Frontiers Media S.A.
publishDate	2021
url	https://doaj.org/article/65716a70d65f4756b68a087f3ec0f42f
work_keys_str_mv	AT karinrettenmaier impactofnanoparticleconsolidationonchargeseparationefficiencyinanatasetio2films AT thomasberger impactofnanoparticleconsolidationonchargeseparationefficiencyinanatasetio2films
_version_	1718440934211846144

Impact of Nanoparticle Consolidation on Charge Separation Efficiency in Anatase TiO2 Films

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