Electrochemical Generation of Excited Intramolecular Charge‐Transfer States

Kapturkiewicz, Andrzej

doi:10.1002/celc.201600865

Cited by 20 publications

(17 citation statements)

References 192 publications

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“…(1)-(4) is simplified as ECL reactants and products are species with distinctly different spin multiplicities, which may lead to additional kinetic complications because of spin conservation rules [7]. Typical luminophores that can undergo such an annihilation pathway are 9,10-diphenylanthracene (DPA), pyrene, tris(bipyridine)ruthenium(II) ([Ru(bpy) 3 ] 2+ ), and 5,6,11,12-tetraphenyltetracene (rubrene) [1,7]. Annihilation rates have been measured directly previously by driving the reaction by high-frequency pulsation of a single electrode between oxidation to reduction overpotentials [8].…”

Section: Introductionmentioning

confidence: 99%

Towards Determining Kinetics of Annihilation Electrogenerated Chemiluminescence by Concentration-Dependent Luminescent Intensity

Mathwig

Šojić

2019

J. Anal. Test.

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In ion-annihilation electrochemiluminescence (ECL), luminophore ions are generated by oxidation as well as reduction at electrodes surfaces, and subsequently recombine into an electronically excited state, which emits light. The intensity of the emitted light is often limited by the kinetic rate of recombination of the luminophore ion species. Recombination or annihilation rates are high ranging up to approximately 10 10 M −1 s −1 and can be difficult to determine using scanning electrochemical microscopy or high-frequency oscillations of an electrode potential. Here, we propose determining annihilation kinetics by measuring the relative change of the emitted light intensity as a function of luminophore concentration. Using finite element simulations of annihilation ECL in a geometry of two closely spaced electrodes biased at constant potentials, we show that, with increasing concentrations, luminescence intensity crosses over from a quadratic dependence on concentration to a linear regime-depending on the rate of annihilation. Our numerical results are applicable to scanning electrochemical microscopy as well as nanofluidic electrochemical devices to determine fast ion-annihilation kinetics.

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Section: Introductionmentioning

confidence: 99%

Towards Determining Kinetics of Annihilation Electrogenerated Chemiluminescence by Concentration-Dependent Luminescent Intensity

Mathwig

Šojić

2019

J. Anal. Test.

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“…The intensity of the emitted light is linked with the efficiency of generating the excited state that depends on the rate of the annihilation reaction. 33 During the process, the redox state of the luminophore is changed either by an electrochemical (i.e. heterogeneous reaction at the electrode|solution interface) or a redox (homogeneous reaction in solution) mean.…”

Section: Energetics and Kineticsmentioning

confidence: 99%

Chapter 1. Introduction and Overview of Electrogenerated Chemiluminescence

Bouffier¹,

Šojić²

2019

Analytical Electrogenerated Chemiluminescence

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This chapter is conceived as a general introduction to electrogenerated chemiluminescence (ECL) for those without prior knowledge of the subject, but with a background in chemistry or biochemistry. The major processes, methods and concepts discussed in this chapter give only a foundation for a first understanding of ECL. After a simple classification of the different types of luminescence, we present the underlying principles of ECL in electrochemistry and photophysics. The basic energetic and kinetic aspects, which involve exergonic electrontransfer reactions are then introduced and briefly described by the Marcus theory. We consider then the different mechanistic pathways leading to the generation of the electronically excited state of the luminophore. This is followed by a short presentation of the main protagonists: the electrode materials, where ECL is initiated, the nature of the luminophores and of the coreactants. Finally, the sensing strategies are presented with the main (bio)analytical applications, which are nowadays successfully commercialized.

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“…Assessing the potential of the three 2CzPN derivatives as OLED materials was possible without the time-intensive and costly task of constructing full OLEDs, since ECL provides a tool to simulate charge imbalances, judge relative stabilities of electrically generated radical cations and anions (holes and electrons, respectively), evaluate relative emission efficiencies and understand emission mechanisms of luminophores. 73,[76][77] Although our reference compound, 2CzPN is a well-studied TADF emitter in the literature, we have redetermined its optoelectronic properties under the same conditions as the three new emitters, as well as calculating its properties, to allow the most accurate comparison.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence and Electrochemiluminescence of Thermally Activated Delayed Fluorescence (TADF) Emitters Containing Diphenylphosphine Chalcogenide-Substituted Carbazole Donors

Kumar

Tourneur

Adsetts

et al. 2021

Preprint

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Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to stabilize the HOMO level relative to the pristine compound, thus increasing the HOMO-LUMO gap and blue-shifting the emission wavelength. By cyclic voltammetry, photophysical data and quantum-chemical calculations, it was found that polar solvents and matrices validated the proposed concept, but these trends were not recovered in non-polar media. The suitability of these 2CzPN derivatives in polar matrices for optoelectronic applications was explored with electrochemiluminescence (ECL) by measuring emission delays, radical stability, emission stabilities, emission efficiencies and emission spectra. Some of the 2CzPN derivatives showed an unprecedented delayed onset of the ECL, and delayed rising time to the ECL maximum, as well as long ECL emission decay. All of these mentioned delay times suggest that these luminophores primarily emit via organic long-persistent electrochemiluminescence (OLECL) mechanisms. The derivatization of the donor groups of the emitters affected both the radical stability and the predominant emission mechanism, providing important insight into their potential as emitters in solid-state electroluminescent devices.

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Electrochemical Generation of Excited Intramolecular Charge‐Transfer States

Cited by 20 publications

References 192 publications

Towards Determining Kinetics of Annihilation Electrogenerated Chemiluminescence by Concentration-Dependent Luminescent Intensity

Towards Determining Kinetics of Annihilation Electrogenerated Chemiluminescence by Concentration-Dependent Luminescent Intensity

Chapter 1. Introduction and Overview of Electrogenerated Chemiluminescence

Photoluminescence and Electrochemiluminescence of Thermally Activated Delayed Fluorescence (TADF) Emitters Containing Diphenylphosphine Chalcogenide-Substituted Carbazole Donors

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