Regular Article

Correlation between photoelectrochemical and photoluminescence measurements of Ag-doped ZnO/ITO photoanode^★

¹ Faculté des sciences de Bizerte, Université de Carthage, Tunis, Tunisia
² Laboratory of Nanomaterials and Systems for Renewable Energies (LaNSER), Research and Technology Center of Energy, Technopôle Borj-Cedria, Hammam-Lif, Tunis, Tunisia

^* e-mail: yousralitaiem@gmail.com

Received: 23 October 2018
Received in final form: 16 December 2018
Accepted: 25 January 2019
Published online: 28 February 2019

Abstract

Silver-doped zinc oxide (SZO) thin films have been deposited onto indium-doped tin oxide substrates (ITO) using sol–gel spin-coating technique with different Ag doping content (1, 2 and 5% Ag). The effect of silver incorporation on structural, morphological, optical and photoelectrochemical (PEC) properties of the SZO films was investigated. Ag incorporation resulted in an enhanced grain size and thickness of elaborated SZO films. Scanning electron micrographs exhibited a uniform distribution of spherical grains with particle size increment after doping. Band gap energies were found to increase after Ag doping. Photoluminescence (PL) measurements revealed that the energy band gaps of the films were in the UV region. As compared to pure ZnO thin film, the samples are more photoactive, and the film containing 2% Ag yielded the highest photocurrent. A correlation study between PEC and PL measurements of Ag-doped ZnO/ITO photoanode leads to a reverse variation. Charge transfer processes at the ZnO–electrolyte interface were identified by electrochemical impedance spectroscopy.