The structural and the photoelectrochemical properties of ZnO–ZnS/ITO 1D hetero-junctions prepared by tandem electrodeposition and surface sulfidation: on the material processing limits - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue RSC Advances Année : 2018

The structural and the photoelectrochemical properties of ZnO–ZnS/ITO 1D hetero-junctions prepared by tandem electrodeposition and surface sulfidation: on the material processing limits

Résumé

ZnO–ZnS 1D hetero-nanostructures were prepared by an easy and scalable processing route. It consists of ZnO nanorod electrodeposition on ITO substrate and surface sulfidation by ion exchange in an aqueous Na 2 S solution. Increasing the treatment contact time (t c) from 8 to 48 h involves different ZnS growth mechanisms leading to different structural and microstructural rod characteristics, even if the overall size does not change significantly. Grazing X-ray diffraction, high-resolution microscopy, energy-dispersive spectrometry and X-ray photoelectron spectroscopy describe the outer surface layer as a poly-and nanocrystalline ZnS blende shell whose thickness and roughness increase with t c. The ZnO wurtzite–ZnS blende interface goes from continuous and dense, at short t c , to discontinuous and porous at long t c , indicating that ZnS formation proceeds in a more complex way than a simple S 2À /O 2À ion exchange over the treatment time. This feature has significant consequences for the photoelectrochemical performance of these materials when they are used as photoanodes in a typical light-assisted water splitting experiment. A photocurrent (J p) fluctuation of 45% for less than 5 min of operation is observed for the sample prepared with a long sulfidation time while it does not exceed 15% for that obtained with a short one, underlining the importance of the material processing conditions on the preparation of valuable photoanodes.

Domaines

Chimie
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Dates et versions

hal-01748875 , version 1 (29-03-2018)

Identifiants

Citer

A. Brayek, S. Chaguetmi, M. Ghoul, I. Ben Assaker, R. Chtourou, et al.. The structural and the photoelectrochemical properties of ZnO–ZnS/ITO 1D hetero-junctions prepared by tandem electrodeposition and surface sulfidation: on the material processing limits. RSC Advances, 2018, 8 (21), pp.11785 - 11798. ⟨10.1039/c8ra00176f⟩. ⟨hal-01748875⟩
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