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New perspectives on the annihilation electrogenerated chemiluminescence of mixed metal complexes in solution
journal contribution
posted on 2023-05-19, 07:22 authored by Kerr, E, Doeven, EH, Barbante, GJ, Hogan, CF, Hayne, DJ, Donnelly, PS, Francis, PSPreliminary explorations of the annihilation electrogenerated chemiluminescence (ECL) of mixed metal complexes have revealed opportunities to enhance emission intensities and control the relative intensities from multiple luminophores through the applied potentials. However, the mechanisms of these systems are only poorly understood. Herein, we present a comprehensive characterisation of the annihilation ECL of mixtures of tris(2,2′-bipyridine)ruthenium(II) hexafluorophosphate ([Ru(bpy)3](PF6)2) and fac-tris(2-phenylpyridine)iridium(III) ([Ir(ppy)3]). This includes a detailed investigation of the change in emission intensity from each luminophore as a function of both the applied electrochemical potentials and the relative concentrations of the two complexes, and a direct comparison with two mixed (Ru/Ir) ECL systems for which emission from only the ruthenium-complex was previously reported. Concomitant emission from both luminophores was observed in all three systems, but only when: (1) the applied potentials were sufficient to generate the intermediates required to form the electronically excited state of both complexes; and (2) the concentration of the iridium complex (relative to the ruthenium complex) was sufficient to overcome quenching processes. Both enhancement and quenching of the ECL of the ruthenium complex was observed, depending on the experimental conditions. The observations were rationalised through several complementary mechanisms, including resonance energy transfer and various energetically favourable electron-transfer pathways.
History
Publication title
Chemical ScienceVolume
7Issue
8Pagination
5271-5279ISSN
2041-6520Department/School
School of Natural SciencesPublisher
Royal Society of ChemistryPlace of publication
Milton Rd, Cambridge, CB4 0WF United KingdomRepository Status
- Restricted