Electrochemically tuneable multi-colour electrochemiluminescence from a single emitter (original) (raw)
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A Demonstration of Simultaneous Electrochemiluminescence
Journal of Chemical Education, 2013
Paired (simultaneous) electrochemical processes can increase energy savings in selected cases by using the reactions at both electrodes of an electrochemical cell to perform a desired process, as is the case in the commercially successful chlor-alkali process. In the demonstration described herein, simultaneous blue electrochemiluminescence (ECL) is obtained with luminol in a basic medium in a divided electrochemical cell. ECL is obtained in the anolyte through the direct oxidation of luminol, the reaction products of which interact with H2O2 in the vicinity of the electrode to yield an excited emitting species. ECL is also obtained in the catholyte through an indirect, mediated process involving the initial reduction of ClO2– to ClO–, which then reacts with luminol and H2O2 to produce the excited emitting species. The co-reactant (H2O2) is needed to complete the reaction sequences in both compartments of the cell. This ECL phenomenon is visible to the naked eye in a darkened room at a distance of up to 5 m.
Spatially-resolved multicolor bipolar electrochemiluminescence
Electrochemistry Communications, 2017
Here, we describe a new aspect of multicolor potential-resolved electrochemiluminescence (ECL) based on bipolar electrochemistry (BPE). BPE involves a potential gradient established along a polarized conducting object which thus acts as a bipolar electrode (BE). The resulting driving forces can induce electron-transfer reactions, necessary for processes such as ECL occurring at different longitudinal locations along the same BE. In this work, we exploit the entire spatial domain where anodic polarization occurs to demonstrate for the first time how the potential gradient along a BE may be used to simultaneously resolve the emissions of ECL-active luminophores with differing oxidation potentials. The control of both size and position of the ECL-emitting domains was achieved by tuning the applied electric field. Multicolor light-emission was analyzed in detail to demonstrate spatial and spectral resolution of a solution containing different emitters.
Organic Electronics, 2018
In this work, we propose an electrochemiluminescence (ECL) luminophore, 2,2′-bipyridylbis(2-phenylpyridine) iridium(III) hexafluorophosphate ([Ir(ppy) 2 (bpy)][PF 6 ]) (1), emitting yellow-colored light for displaying a variety of ECL colors. The synthesized luminophore 1 is optically and electrochemically analyzed. The ECL electrolytes are very simply composed of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI] [TFSI]), sandwiched between two transparent electrodes used for the devices. The resulting ECL devices are characterized by a low-voltage operation and quick response independent of frequency. We also suggest an efficient method for improving the ECL brightness by incorporating 2,2′-bipyridylbis[2-(2′,4′-difluorophenyl) pyridine]iridium(III) hexafluorophosphate ([Ir(diFppy) 2 (bpy)][PF 6 ]) (2) as a coreactant. The intensity of the emitted yellow light is doubled, when 60 mol% of 2 is included in the mixed-luminophore system. Additionally, we further enhanced the luminance of yellow light emitting ECL devices by adjusting the frequency of applied AC voltage, leading to ∼3.5 times higher brightness at 500 Hz.
Electrogenerated Chemiluminescence
Annual Review of Analytical Chemistry, 2009
In electrogenerated chemiluminescence, also known as electrochemiluminescence (ECL), electrochemically generated intermediates undergo a highly exergonic reaction to produce an electronically excited state that then emits light. These electron-transfer reactions are sufficiently exergonic to allow the excited states of luminophores, including polycyclic aromatic hydrocarbons and metal complexes, to be created without photoexcitation. For example, oxidation of [Ru(bpy) 3 ] 2+ in the presence of tripropylamine results in light emission that is analogous to the emission produced by photoexcitation. This review highlights some of the most exciting recent developments in this field, including novel ECL-generating transition metal complexes, especially ruthenium and osmium polypyridine systems; ECL-generating monolayers and thin films; the use of nanomaterials; and analytical, especially clinical, applications.
ChemElectroChem, 2018
Herein, we propose an effective methodology to improve the brightness of Ru(bpy) 3 2+based ECL devices driven by the annihilation path, based on an understanding of the great importance of concentration balance between oxidized (Ru(bpy) 3 •3+) and reduced (Ru(bpy) 3 •1+) species. From cyclic voltammetry experiments, we verify that Ru(bpy) 3 •3+ is more stable than Ru(bpy) 3 •1+ , which is a fundamental physical parameter for balanced electrochemical annihilation reaction. Accordingly, we adjust the symmetry (i.e. the dutyratio) of the input AC voltage to control the concentrations of redox species. The frequency and peak-to peak voltage (V pp) are fixed at 60 Hz and 7.5 V pp. When the duty-ratio is 40%, the luminance of ~174 Cd/m 2 is detected, which is brighter than the ~148 Cd/m 2 achieved under a symmetric voltage wave. We investigate the feasibility of further enhancing device luminance by modulating the frequency of applied voltage at the fixed duty-ratio of 40%, achieving the maximum luminance of ~207 Cd/m 2 at 150 Hz. Overall, this work elucidates a critical role of electrochemical stability of redox species that participate in the light-emitting annihilation reaction and suggests a simple but effective route (e.g. adjusting symmetry of AC input) to improve luminance of ECL devices.
Recent applications of electrogenerated chemiluminescence in chemical analysis
Talanta, 2001
Analytical applications of electrogenerated chemiluminescence (ECL) are reviewed with emphasis on the years 1997-2000. Recent developments are described for the ECL of organics, metal complexes and clusters, cathodic ECL on oxide covered electrodes, ECL based immunosensors, DNA-probe assays and enzymatic biosensors. Mechanisms are given for polyaromatic hydrocarbons, luminol/hydrogen peroxide, some cathodic ECL reactions and ruthenium complexes with and without co-reactants. New developments and improvements of techniques and instrumentation and their application to analytes are described. The application of ECL for visualisation of electrochemical processes and imaging of surfaces is mentioned.
Analytical Chemistry, 2009
Bipolar electrodes are potentially useful for a variety of sensing applications, but their implementation has been hampered by an inability to easily monitor the current through such electrodes. However, current can be indirectly determined using electrogenerated chemiluminescence (ECL) as a reporting mechanism. This paper provides a detailed theoretical analysis of ECL reporting at bipolar electrodes. In addition, experiments are described that confirm the theory. Finally, we correlate ECL intensity directly to current through the use of split bipolar electrodes. The results indicate that the lowest current that can be indirectly detected through ECL reporting is ∼32 µA/cm 2 , which corresponds to a reporting sensitivity of ∼7200 counts/nA in the present experimental system.
Electrogenerated Chemiluminescence for Immunoassay Applications
Indonesian Journal of Chemistry, 2021
Electrogenerated chemiluminescence (ECL) has recently become one of the most prominent and well-established transducers for immunoassay techniques. ECL relates a luminophore concentration in solution with the emission of light triggered by an electrochemical stimulus. ECL immunoassay (ECLIA) performance depends on the parameters of its light generation, including the luminophore, the species that emit light called labels in ECLIA; co-reactants, which are added reagents that support the luminophore to undergo the excited state; electrodes, which are the place for the ECL reactions to take place; and the format of the immunoassay. This review discusses the behaviour of ECLIA parameters, the required instrumentations, and some important examples of detections based on ECLIA.