| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2014) | |
| Nanomaterials | Tuesday Sessions |
| Session NM-TuP |
| Session: | Nanomaterials Poster Session |
| Presenter: | Adam Hitchcock, McMaster University, Canada |
| Authors: | AP. Hitchcock, McMaster University, Canada X. Zhu, McMaster University, Canada C. Bittencourt, University of Mons, Belgium P. Umek, Jožef Stefan Institute, Slovenia P. Krüger, Chiba University, Japan |
| Correspondent: | Click to Email |
TiOx-based nanostructures are being used as active materials in lithium ion batteries, gas sensors, photocatalysts, dye synthesized solar cells, etc. Much effort has been directed toward understanding their electronic properties [1] because they exhibit physical and chemical properties different from their bulk counterparts. They are challenging to study by analytical electron microscopy techniques since they are highly sensitive to radiation damage. Their nano-scale prevents the use of conventional X-ray absorption spectroscopy (NEXAFS) to study individual structures. Scanning transmission x-ray microscopy (STXM) allows studies of the electronic structure of individual nanomaterials with high spatial resolution (30 nm) and high energy resolution (0.1 Ev) via NEXAFS spectroscopy and its linear dichroism (spectral variation as a function of the E-vector orientation) [2]. Here we report STXM-NEXAFS studies of individual sodium titanate nanoribbons (NaTiOx-NR) prepared by hydrothermal treatment of anatase TiO2 micro-particles [3]. By measuring the dichroism with the sample at different orientations relative to the X-ray beam, and varying the direction of the linear E-vector by an elliptically polarizing undulator (EPU), the linear dichroism at the O 1s and Ti 2p edges was measured along the 3 principle axes of the anisotropic nanoribbons. Comparison of the spectra and dichroism with high level calculations helps confirm the crystal structure [4] and gives insight into the electronic bonding in these novel layered materials through the orientation dependence of local electronic structure within the crystallite. The methodology for 3D dichroic STXM measurements newly developed in this study is a powerful way to investigate anisotropic nanomaterials.
Research carried out at the Canadian Light Source, which is supported by NSERC, CIHR, NRC and the University of Saskatchewan. Research funded by NSERC, Canada Research Chair.
[1] P. Krüger, Phys. Rev. B 81 (2010) 125121.
[2] A.P. Hitchcock,Soft X-ray Imaging and Spectromicroscopy Ch. 22 in Handbook on Nanoscopy, eds. G. Van Tendeloo, D. Van Dyck and S.J. Pennycook (Wiley, 2012) 745.
[3] P. Umek, R. C. Korošec, B. Jančar, R. Dominko, D. Arčon, J. Nanosci. Nanotechnol.7 (2007) 3502.