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 TiO2 (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. D-app = 2 (+/- 1) x 10(-15) m(2) 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. (C) 2011 Elsevier B.V. All rights reserved.