1Laboratory of Biophysics, Faculty of Electrical Engineering, University of Ljubljana, Tržaška 25, SI 1000 Ljubljana, Slovenia
2Jožef Stefan Institute, Department of Surface Engineering and Optoelectronics, Jamova 39, SI-1000 Ljubljana, Slovenia
3Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana, Zdravstvena 5, SI-1000 Ljubljana, Slovenia
4Materials Research Laboratory, University of Nova Gorica, Vipavska 13, SI-5000 Nova Gorica, Slovenia
5Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China
6Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Zaloška 9 5, SI-1000 Ljubljana, Slovenia
Adv. Mater. Lett., 2018, 9 (10), pp 708-714
Publication Date (Web): Jul 18, 2018
Copyright © IAAM-VBRI Press
The photocatalytic activity of TiO2 nanotubes (NTs) makes these materials promising candidates for a variety of applications, including photocatalytic degradation, water splitting and biomedical devices. The large band gap of TiO2 (anatase ∼3.2 eV; rutile ∼ 3.0 eV) requires excitation with UV light, which accounts for only a small fraction of solar light. In order to increase the light absorption in the visible region, reduction of the band gap is required. Here, TiO2 nanotubes (NTs) were fabricated by electrochemical anodization of Ti foil. Scanning electron microscopy (SEM), X-ray diffraction analysis (XRD) and X-ray photoemission spectroscopy (XPS) were used to determine morphology, crystal structure and surface composition of the TiO2 NTs. Different synthesis conditions influenced TiO2 NTs properties that allowed the tuning of the band gap. UV-Vis analysis of 61.54 µm long NTs showed light absorption over the whole visible range, while NTs with the length up to 0.21 µm are able to absorb only UV light. 61.54 µm long NTs exhibited band tailing up to 1.43 eV.
TiO2 nanotubes, electrochemical anodization, visible light absorption, band gap.