Passivation layers for nanostructured photoanodes : Ultra-thin oxides on InGaN nanowires
Neuderth, Paula (Justus Liebig University Giessen)
Hille, Pascal (University of Bremen. Institute of Solid State Physics)
Schörmann, Jörg (Justus Liebig University Giessen)
Frank, A. (Justus Liebig University Giessen)
Reitz, C. (Karlsruhe Institute of Technology)
Martí-Sánchez, Sara (Institut Català de Nanociència i Nanotecnologia)
De La Mata, Maria (Institut Català de Nanociència i Nanotecnologia)
Coll, Mariona (Institut de Ciència de Materials de Barcelona)
Arbiol i Cobos, Jordi (Institut Català de Nanociència i Nanotecnologia)
Marschall, R. (Justus Liebig University Giessen)
Eickhoff, Martin (University of Bremen)

Date:	2018
Abstract:	An experimental strategy for systematically assessing the influence of surface passivation layers on the photocatalytic properties of nanowire photoanodes by combining photocurrent analysis, photoluminescence spectroscopy and high resolution transmission electron microscopy with a systematic variation of sample structure and the surrounding electrolyte is demonstrated. Following this approach we can separate the impact on recombination and transport processes of photogenerated carriers. We apply this strategy to analyze the influence of ultra-thin TiO, CeO and AlO coatings deposited by atomic layer deposition on the photoelectrochemical performance of InGaN/GaN nanowire (NW) photoelectrodes. The passivation of surface states results in an increase of the anodic photocurrent (PC) by a factor of 2. 5 for the deposition of 5 nm TiO. In contrast, the PC is reduced for CeO- and AlO-coated NWs due to enhanced defect recombination in the passivation layer or increased band discontinuities. Furthermore, photoelectrochemical oxidation of the InGaN/GaN NW photoelectrode is attenuated by the TiO layer and completely suppressed for a layer thickness of 7 nm or more. Due to efficient charge transfer from the InGaN NW core a stable TiO-covered photoanode with visible light excitation is realized.
Grants:	Ministerio de Economía y Competitividad RYC-2013-12448 Ministerio de Economía y Competitividad SEV-2015-0496 Agència de Gestió d'Ajuts Universitaris i de Recerca 2014/SGR-1638 Ministerio de Economía y Competitividad MAT2014-59961-C2-2-R Ministerio de Economía y Competitividad SEV-2013-0295
Rights:	Tots els drets reservats.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Defect recombinations ; Experimental strategy ; Photo-electrochemical oxidations ; Photocatalytic property ; Photocurrent analysis ; Photoelectrochemical performance ; Photogenerated carriers ; Visible light excitation
Published in:	Journal of materials chemistry, Vol. 6, Issue 2 (January 2018) , p. 565-573, ISSN 2050-7496

DOI: 10.1039/c7ta08071a

Postprint 19 p, 1.0 MB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Catalan Institute of Nanoscience and Nanotechnology (ICN2)
Articles > Research articles
Articles > Published articles