Electrochemical fabrication and potential-enhanced luminescence of [Ru(bpy)2tatp]2+ incorporating DNA-stabilized single-wall carbon nanotubes on an indium tin oxide electrode

A simple method was developed for the preparation of [Ru(bpy)2tatp]2+-based aggregates (where bpy = 2,2′-bipyridine, tatp = 1,4,8,9-tetra-aza-triphenylene) on an indium tin oxide (ITO) electrode in the presence of DNA-stabilized single-walled carbon nanotubes (DNA–SWCNTs). The presence of SWCNTs in the concentration range from 0.02 to 0.125 g L−1 dispersed with 0.25 mmol L−1 DNA was found to promote the immobilization of [Ru(bpy)2tatp]2+ on the ITO electrode by the method of repetitive voltammetric sweeping. The photoluminescence of [Ru(bpy)2tatp]2+ incorporating DNA–SWCNTs both in solution and on the ITO electrode was systematically investigated by emission spectra and fluorescence microscopic imaging. An excess amount of SWCNTs can quench the photoluminescence of [Ru(bpy)2tatp]2+ enhanced by DNA. The anodic potentials combined with CW green laser via an optical microscope was found to significantly increase the emission intensity of [Ru(bpy)2tatp]2+–DNA–SWCNTs aggregates on the ITO electrode. In addition, the electrochemical fabrication and photoluminescence principles of [Ru(bpy)2tatp]2+–DNA–SWCNTs aggregates on the ITO electrode tuned by the external electric fields were discussed in detail.