Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films

Photo-excited charge carriers play a vital role in photocatalysts and photovoltaics, and their dynamic processes must be understood to improve their efficiencies by controlling them. The photo-excited charge carriers in photocatalytic materials are usually trapped to the defect states in the picosec...

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Autores principales:	Kenji Katayama, Tatsuya Chugenji, Kei Kawaguchi
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	photo-excited charge carrier dynamics defect states titanium oxide strontium titanium oxide hematite bismuth vanadate Technology T
Acceso en línea:	https://doaj.org/article/8341112055ad4d8395df250788285df4
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spelling	oai:doaj.org-article:8341112055ad4d8395df250788285df42021-11-11T15:49:40ZCharge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films10.3390/en142170111996-1073https://doaj.org/article/8341112055ad4d8395df250788285df42021-10-01T00:00:00Zhttps://www.mdpi.com/1996-1073/14/21/7011https://doaj.org/toc/1996-1073Photo-excited charge carriers play a vital role in photocatalysts and photovoltaics, and their dynamic processes must be understood to improve their efficiencies by controlling them. The photo-excited charge carriers in photocatalytic materials are usually trapped to the defect states in the picosecond time range and are subject to recombination to the nanosecond to microsecond order. When photo-excited charge carrier dynamics are observed via refractive index changes, especially in particulate photocatalytic materials, another response between the trapping and recombination phases is often observed. This response has always provided the gradual increase of the refractive index changes in the nanosecond order, and we propose that the shallowly trapped charge carriers could still diffuse and be trapped to other states during this process. We examined various photocatalytic materials such as TiO<sub>2</sub>, SrTiO<sub>3</sub>, hematite, BiVO<sub>4</sub>, and methylammonium lead iodide for similar rising responses. Based on our assumption of surface trapping with diffusion, the responses were fit with the theoretical model with sufficient accuracy. We propose that these slow charge trapping processes must be included to fully understand the charge carrier dynamics of particulate photocatalytic materials.Kenji KatayamaTatsuya ChugenjiKei KawaguchiMDPI AGarticlephoto-excited charge carrier dynamicsdefect statestitanium oxidestrontium titanium oxidehematitebismuth vanadateTechnologyTENEnergies, Vol 14, Iss 7011, p 7011 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	photo-excited charge carrier dynamics defect states titanium oxide strontium titanium oxide hematite bismuth vanadate Technology T
spellingShingle	photo-excited charge carrier dynamics defect states titanium oxide strontium titanium oxide hematite bismuth vanadate Technology T Kenji Katayama Tatsuya Chugenji Kei Kawaguchi Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films
description	Photo-excited charge carriers play a vital role in photocatalysts and photovoltaics, and their dynamic processes must be understood to improve their efficiencies by controlling them. The photo-excited charge carriers in photocatalytic materials are usually trapped to the defect states in the picosecond time range and are subject to recombination to the nanosecond to microsecond order. When photo-excited charge carrier dynamics are observed via refractive index changes, especially in particulate photocatalytic materials, another response between the trapping and recombination phases is often observed. This response has always provided the gradual increase of the refractive index changes in the nanosecond order, and we propose that the shallowly trapped charge carriers could still diffuse and be trapped to other states during this process. We examined various photocatalytic materials such as TiO<sub>2</sub>, SrTiO<sub>3</sub>, hematite, BiVO<sub>4</sub>, and methylammonium lead iodide for similar rising responses. Based on our assumption of surface trapping with diffusion, the responses were fit with the theoretical model with sufficient accuracy. We propose that these slow charge trapping processes must be included to fully understand the charge carrier dynamics of particulate photocatalytic materials.
format	article
author	Kenji Katayama Tatsuya Chugenji Kei Kawaguchi
author_facet	Kenji Katayama Tatsuya Chugenji Kei Kawaguchi
author_sort	Kenji Katayama
title	Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films
title_short	Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films
title_full	Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films
title_fullStr	Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films
title_full_unstemmed	Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films
title_sort	charge carrier trapping during diffusion generally observed for particulate photocatalytic films
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/8341112055ad4d8395df250788285df4
work_keys_str_mv	AT kenjikatayama chargecarriertrappingduringdiffusiongenerallyobservedforparticulatephotocatalyticfilms AT tatsuyachugenji chargecarriertrappingduringdiffusiongenerallyobservedforparticulatephotocatalyticfilms AT keikawaguchi chargecarriertrappingduringdiffusiongenerallyobservedforparticulatephotocatalyticfilms
_version_	1718433711562686464

Charge Carrier Trapping during Diffusion Generally Observed for Particulate Photocatalytic Films

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