Effects of type of binder and conducting phase on the performance of solid-state electrochemiluminescence composites

The electrochemiluminescence (ECL) of tris(2,2-bipyridyl)ruthenium [Ru(bpy)3 ](2+) has received much attention. By immobilizing [Ru(bpy)3 ](2+) on an electrode surface, solid-state ECL has several advantages over solution-phase ECL, such as reduced amounts of costly reagent and a simplified experimental design. Herein, different types of solid-state ECL sensors were fabricated and the performances of paraffin oil and two ionic liquids (ILs) as the binders were compared for the construction of solid-state ECL. Scanning electron microscopy (SEM), CCD camera, UV-vis, fluorescence spectroscopy, electrochemistry and ECL were applied to characterize and evaluate the performance of the solid-state composites. According to the obtained results, Ru-graphite/IL octyl pyridinium hexaflurophosphate (OPPF6 ) was introduced as a new solid-state ECL with excellent properties such as simple preparation, low background current, fast electron-transfer rate and good reproducibility and stability. Moreover, for a study of the effect of carbon structure on the performance of the electrode, graphite was replaced by multi-walled carbon nanotubes (MWCNTs) and Ru-MWCNT/OPPF6 was constructed and its efficiency was compared with Ru-graphite/OPPF6 composite electrode.