Determining absolute electrochemiluminescence efficiencies of two iridium complexes

Yang, Liuqing; Adsetts, Jonathan Ralph; Zhang, Ruizhong; Balónová, Barbora; Piqueras, Marta Tomás; Chu, Kenneth; Zhang, Congyang; Zysman‐Colman, Eli; Blight, Barry A.; Ding, Zhifeng

doi:10.1016/j.jelechem.2021.115891

Cited by 19 publications

(13 citation statements)

References 45 publications

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“…There are currently Ru(bpy) 3 2+ /TPrA coreactant systems tested and Ir(ppy) 3 /benzoyl peroxide (BPO) systems tested, but these experiments employed compounds with much different concentrations, and a direct comparison is therefore difficult. 28,43 Φ AQE Verification with 1 mM Ru(bpy) 3 2+ in Pulsing Mode. To verify the accuracy and precision of this new strategy to determine Φ AQE by means of a CCD the conventional standard ECL emitter, Ru(bpy) 3 2+ that has a known Φ AQE value tested in the annihilation pathway was determined to produce Figure 5.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Absolute Electrochemiluminescence Quantum Efficiency of Au Nanoclusters by Means of a Spectroscopy Charge-Coupled Device Camera

et al. 2022

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Currently, the electrochemiluminescence (ECL) efficiency of a luminophore is evaluated by measuring the ratio of ECL intensity generated by a certain number of electrons injected. Then, this ratio is compared to that of the commercial luminophore, Ru(bpy)3 2+ under the same test conditions. However, the ECL intensity from a luminophore will be different on every instrumental setup due to wavelength-specific interaction of light with photodetectors. Also, previous absolute ECL techniques require multiple instruments, each of which has its own wavelength-specific light losses leading to complicated hardware and calculation requirements. Herein, this paper presents an absolute way to evaluate the ECL quantum efficiency (QE), permitting researchers to quickly compare ECL results and elucidate ECL mechanisms. The accuracy and precision of this new physical strategy is verified with the well-studied Ru(bpy)3 2+ to find an ECL QE of 0.64%. The strategy was then exemplified with Au25 0(SC2H4Ph)18 to represent a difficult spectroscopic challenge and this ECL QE was found to be 0.0062%. Finally, Ru(bpy)3 2+ ECL QE at different TPrA concentrations was evaluated to understand how the TPrA concentration affects the ECL QE of Ru(bpy)3 2+. Significant Ru(bpy)3 2+ ECL QE decreases were viewed from 3.2 × 10–3% at 6.25 mM TPrA to 6.5 × 10–6% at 200 mM TPrA likely due to high excited state quenching. Along with our previous publications on Au cluster ECL, discussed are factors influencing the ECL intensity such as the diffusion of electroactive molecules, the stability of radicals, the reactivity of excited states, and the analyte’s reactivity. Profound variations were observed on this finding, which has large implications for past, current, and future relative ECL efficiencies also discussed in length.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Absolute Electrochemiluminescence Quantum Efficiency of Au Nanoclusters by Means of a Spectroscopy Charge-Coupled Device Camera

et al. 2022

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“…As demonstrated in Figure 1A, the coreactant BPO was reduced at a cathodic peak potential of −1.20 V to generate BPO radical anion [11c] that easily decomposed into PhCOO⋅ and benzoate (Figure 2). When 2c was reduced to form 2c .− at around −1.80 V, the PhCOO⋅ as a strong oxidant can extract an electron from the HOMO of 2c .− to produce excited state 2c*, which then emitted ECL.…”

Section: Resultsmentioning

confidence: 99%

“…Spooling ECL spectroscopy was employed to study the kinetic of the ECL, which can monitor the real‐time ECL during a potential scan and observe the evolution and devolution of the ECL [6,11c] . Figure 3 presents the spooling ECL spectra of 2c acquired with CV scan upon addition of 5 mM BPO as the coreactant, collecting with a potential cycle between −1.70 V and −2.0 V. Three distinguishable ECL features are displayed in these spectra, including red (forward scan, from −1.80 to −1.94 V), blue (forward scan, from −1.94 to −1.94 V) and green (backward scan, from −1.94 to −1.80 V) districts.…”

Section: Resultsmentioning

confidence: 99%

“…The electrochemical experiments were conducted on an Autolab potentiostat (PGSTAT30, Metrohm, Switzerland) with a three‐electrode system. A Pt disk electrode ( d =2 mm) was used as the working electrode that was cleaned as reported before [11c] . The other two Pt coils were used as reference and counter electrodes.…”

Section: Methodsmentioning

confidence: 99%

“…As reported elsewhere, [11c] the absolute ECL quantum efficiency ( Φ x,a ) was measured by comparing the number of photons emitted with the number of electrons injected. Considering the factors of self‐absorption, non‐Faradaic current, difference of PMT's sensitivity to ECL emission at specific wavelength and so on, the absolute ECL efficiency was detected using equation :

true Φ_{x, a} = (\frac{\int_{a}^{b} P C d t}{\int_{a}^{b} ((||, i_{x}) - (||, i_{B G})) d t} \times \frac{N_{A} \times k_{A B S} \times q_{e}}{F \times C \times σ_{P M T}}) \times 100 %

…”

Section: Methodsmentioning

confidence: 99%

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Correlating Structures to Electrochemiluminescence Efficiencies of Silole Compounds in Coreactant Systems

et al. 2022

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To develop efficient electrochemiluminescence (ECL) of activated silole chromophores, the relative ECL efficiencies of eight thiophene‐containing compounds are firstly studied in a coreactant pathway. The experimental results show that the extended π‐conjugated systems and donor groups of the silole emitters affect both the radical stability and emission efficiencies. It is found that the 1,1‐di‐tert‐butyl‐2,5‐bis[(2,2′‐bithiophen)‐5‐yl]‐3,4‐diphenylsilole (2c) compound with benzoyl peroxide (BPO) as a coreactant exhibits the highest relative ECL efficiencies among the studied systems due to its structural properties. Moreover, the absolute ECL efficiency of the potential pulsing/ECL experiment in the coreactant pathway is 6‐fold larger than that in the potentiodynamic experiment due to the short time interval for the radical species to meet and react. This work provides a guidance for structural modification of silole compounds to tune ECL performance.

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Electrocatalytic Effects of Au Nanoclusters in its Electrochemiluminescence Enhanced by Coreactant Tertiary Amines

Ma,

Yang,

et al. 2024

ChemElectroChem

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Atomically precise metal nanoclusters are increasingly exploited in electrocatalysis such as water electrolysis and CO2 reduction. The catalytic effects are generally evaluated by conventional electrochemical methods or end‐product analysis. Herein, near infrared electrochemiluminescence (ECL) of the nanoclusters is introduced as a new signaling mechanism to complement classical voltammetric analysis for elucidating essential electrocatalytic parameters. Coreactant ECL from an aqueous soluble Au22 nanocluster (NCs) enhanced by a common pH buffer materials 4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) and by a piperazine drug hydroxyzine (HDZ) is studied under oxidative reduction pathways. Foot of the wave analysis on voltametric features and the kinetics profiles in potential‐step experiments are studied in different nanocluster and coreactant concentrations. Benchmark parameters such as rate constants are determined under EC (Electron‐transfer‐Chemical‐reaction) mechanism as feasibility validations. Because the luminescence properties of AuNCs are sensitive to the surface ligands or adsorbents, ECL is proposed as a new signal readout for operando studies providing insights for governing reaction mechanism and kinetics during catalytic reactions. Retrospectively, mechanistic understanding of the complex multi‐step reactions during ECL generation can provide guidance for the evaluation and optimization of ECL property for better quantitative applications.

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Determining absolute electrochemiluminescence efficiencies of two iridium complexes

Cited by 19 publications

References 45 publications

Absolute Electrochemiluminescence Quantum Efficiency of Au Nanoclusters by Means of a Spectroscopy Charge-Coupled Device Camera

Absolute Electrochemiluminescence Quantum Efficiency of Au Nanoclusters by Means of a Spectroscopy Charge-Coupled Device Camera

Correlating Structures to Electrochemiluminescence Efficiencies of Silole Compounds in Coreactant Systems

Electrocatalytic Effects of Au Nanoclusters in its Electrochemiluminescence Enhanced by Coreactant Tertiary Amines

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