We present a new approach to explore the potential-dependent multi-colour co-reactant electrochemiluminescence (ECL) from multiple luminophores. The potentials at both the working and counter electrodes, the current between these electrodes, and the emission over cyclic voltammetric scans were simultaneously measured for the ECL reaction of Ir(ppy)3and either [Ru(bpy)3]2+or [Ir(df-ppy)2(ptb)]+, with tri-n-propylamine as the co-reactant. The counter electrode potential was monitored by adding a differential electrometer module to the potentiostat. Plotting the data against the applied working electrode potential and against time provided complementary depictions of their relationships. Photographs of the ECL at the surface of the two electrodes were taken to confirm the source of the emissions. This provided a new understanding of these multifaceted ECL systems, including the nature of the counter electrode potential and the possibility of eliciting ECL at this electrode, a mechanism-based rationalisation of the interactions of different metal-complex luminophores, and a previously unknown ECL pathway for the Ir(ppy)3complex at negative potentials that was observed even in the absence of the co-reactant.
Funding
The authors thank Deakin University, the Australian Research Council (DP200102947) and the Royal Society (IES\R3\170367) for funding this work. E. K. thanks National Health and Medical Research Council (NHMRC) of Australia (GNT1161573).
History
Publication Date
2021-07-28
Journal
Chemical Science
Volume
12
Issue
28
Pagination
(p. 9770-9777)
Publisher
ROYAL SOC CHEMISTRY
ISSN
2041-6520
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