Electrochemiluminescence

Electrogenerated chemiluminescence (ECL) is the process in which electrogenerated radical anions and cations combine in solution, produce an excited species via electron transfer and emit light. ECL has become a powerful analytical technique in immunoassays, food and water testing, trace metal determination, and biomolecule detection. In our laboratory, we study a variety of compounds, ranging from metal complexes, organic molecules, modified nucleobases, dyes, polymers, atomic clusters, nanocrystals in the visible and near-infrared regions. We perform cyclic voltammetry (CV), differential pulse voltammetry (DPV), and ECL to study the mechanisms in which light is generated from the compounds in solutions

ECL via annihilation is the process by which a luminophore species in solution is scanned or pulsed to its first oxidation and reduction potentials at a working electrode. The generation of its radical anion and radical cation in the vicinity of the electrode will produce the excited state species. ECL results from the excited state species relaxing back down to its ground state and emitting light.

An alternative to annihilation ECL is using a coreactant system. Here, one directional potential scanning at the working electrode in a solution containing the luminophore species with added coreactant (such as benzoyl peroxide, BPO) is performed. Radicals are generated from the luminophore, and coreactant that reacts to give off an excited species that emits light.

In order to see the evolution of light emission, we have developed a new technique called spooling that captures the spectrum every second for a given amount of time period while scanning the compound using CV. With the spooling technique we can track the potential at which ECL emission occurs. Using spooling we can identify multiple ECL emissions individually ECL is a valuable analytical technique that is cost effective, fast, highly sensitive and selective and tunable, requiring minimal amount of compound and solvent.

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