Focused ion beam (FIB) machining allowed a sub-micron trench to be cut through tin-doped indium oxide (ITO) film on glass to give a generator - collector junction electrode with narrow gap (ca. 600 nm). A layer-by-layer deposited film composed of a dinuclear ruthenium(II)-bis(benzimidazolyl) pyridine-phosphonate (as the negative component) and nanoparticulate TiO 2 (ca. 6 nm diameter, as the positive component) was formed and investigated first on simple ITO electrodes and then on ITO junction electrodes. The charge transport within this film due to Ru(II/III) redox switching (electron hopping) was investigated and an apparent diffusion coefficient of ca. Dapp = 2 (± 1) × 10-15 m2 s -1 was observed with minimal contributions from intra-molecular Ru-Ru interactions. The benefits of FIB-cut ITO junctions as a tool in determining charge hopping rates are highlighted.
Bibliographical noteFunding Information:
Dr. Suguo Huo and Dr. Paul Warburton are gratefully acknowledged for allowing access to the EPSRC FIB service at UCL. C.Y.C. thanks the EPSRC for a studentship. M.H. acknowledges the financial support received from the Ministry of Education, Culture, Sports, Science and Technology for a Grant-in-Aid for Priority Area “Coordination Programming” (No. 21108003) and also for Scientific Research (No. 21350082).
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Chemical Engineering(all)