Title: Multilayer films of indium tin oxide/TiO2 codoped with vanadium and nitrogen for efficient photocatalytic water splitting

Authors: Z. El Koura; N. Patel; R. Edla; A. Miotello

Addresses: Laboratorio IdEA (Idrogeno, Energia, Ambiente), Department of Physics - University of Trento, Via Sommarive 14, I-38123 Povo (TN), Italy ' Laboratorio IdEA (Idrogeno, Energia, Ambiente), Department of Physics - University of Trento, Via Sommarive 14, I-38123 Povo (TN), Italy ' Laboratorio IdEA (Idrogeno, Energia, Ambiente), Department of Physics - University of Trento, Via Sommarive 14, I-38123 Povo (TN), Italy ' Laboratorio IdEA (Idrogeno, Energia, Ambiente), Department of Physics - University of Trento, Via Sommarive 14, I-38123 Povo (TN), Italy

Abstract: TiO22 films codoped with V cations and N anions were synthesised by RF-magnetron sputtering. The incorporation of V and N in TiO2 lattice produces isolated energy levels near the conduction and valence bands, respectively, causing an effective narrowing of the band gap to 2.5 eV. Recombination of photo-charges was reduced by depositing multilayer films of indium tin oxide (ITO)/V-N-codoped TiO2 with different numbers of bilayers. In multilayer structure, the generated photoelectrons, travelling into TiO2 film of limited thickness, rapidly enter the space charge interface of the ITO/TiO2 films from where they are instantaneously injected into the ITO layer and then removed towards the cathode. The synergic effects created by band narrowing and enhanced charge separation by using codoping and multilayer structure strategy in TiO2 generate higher photocurrent for water splitting under visible light which definitely exceeds that obtained by doping TiO2 with a single, V or N, element.

Keywords: nanotechnology; titanium dioxide; titania; co-doping; photocatalytic water splitting; multilayer structure; visible light irradiation; thin films; RF-magnetron sputtering; photoelectrochemical cells; charge recombination; TiO2 red shift; green technology; vanadium; nitrogen.

DOI: 10.1504/IJNT.2014.064297

International Journal of Nanotechnology, 2014 Vol.11 No.9/10/11, pp.1017 - 1027

Published online: 15 Aug 2014 *

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