Cathodic electrogenerated chemiluminescence of Ru(bpy)32+ chelate at oxide-coated heavily doped silicon electrodes

High amplitude cathodic pulse polarization of ultra thin oxide film-coated heavily doped silicon electrodes induces tunnel emission of hot electrons into aqueous electrolyte solution, which probably results in the generation of hydrated electrons in the vicinity of the electrode surface. The method allows the detection of tris (2,2′-bipyridine) ruthenium(II) chelate at subnanomolar concentration level. This paper shows that both n- and p-type heavily doped silicon electrodes can be used, illustrates the effect of oxide film thickness upon the silicon electrode on the intensity of ECL of tris (2,2′-bipyridine) ruthenium(II) and discusses the basic features of tris (2,2′-bipyridine) ruthenium(II) chelate-specific ECL at these electrodes. Thin oxide film-coated silicon electrodes provide a lower blank emission and a higher ECL intensity of the present ruthenium chelate than oxide-covered aluminium electrodes. This suggests that thin oxide film-coated silicon is a very promising working electrode material, especially in microanalytical systems made fully or partly of silicon.