Electrochemical Properties of Transparent Conducting Films of Tantalum-Doped Titanium Dioxide. (1st April 2017)

• Record Type: Journal Article
• Authors: Krysova, Hana; Mazzolini, Piero; Casari, Carlo S.; Russo, Valeria; Bassi, Andrea Li; Kavan, Ladislav
• Is Part Of: Electrochimica acta. Volume 232(2017)
• Page Start: 44
• Page End: 53
• Publication Date: 2017-04-01
• Subjects: titanium dioxide -- tantalum doping -- electrochemistry -- UV-photoelectrochemistry -- Li-insertion; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2017.02.124
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Highly conducting, optically transparent Ta-doped TiO2 (anatase) thin films are grown on ordinary soda-lime glass substrates by pulsed-laser deposition. They exhibit quasi-reversible cyclic voltammograms of Fe(CN)6 3−/4− and dimethylviologen redox couples, mimicking the electrochemical activity of F-doped SnO2 (FTO). Hence, our Ta-doped titania films can prospectively replace FTO, e.g. in homo-junction dye-sensitized and perovskite solar cells. However, these films are idle for the Ru(bpy)3 2+ oxidation, which is attributed to the space-charge barrier. The flatband potential of our Ta-doped TiO2 is comparable to that of an undoped reference film and/or of the pristine anatase single-crystal electrode. Our films show photoelectrochemical activity upon irradiation with UV light at potentials positive to flatband. The UV-photocurrents decrease proportionally to the increase of Ta-content. The Li-insertion ability analogously decreases with increasing Ta-content. This is attributed to the positive charge of Ta 5+ cations which occupy the Ti 4+ sites in anatase lattice and thus impede the Li + -transport. Consistent with the quasi-metallic nature of our films, the Li-extraction peak in cyclic voltammograms shows no cut at larger potentials.