Pre‐oxidation of Gold Nanoclusters Results in a 66 % Anodic Electrochemiluminescence Yield and Drives Mechanistic Insights

Abstract

Gold nanoclusters (AuNCs) are attractive electrochemiluminescence (ECL) emitters because of their excellent stability,n ear IR emission, and biocompatibility.H owever, their ECL quantum yield is relatively low,a nd our limited fundamental understanding has hindered rational improvement of this parameter.Herein, we report drastic enhancement of the ECL of ligand-stabilized AuNCs by on-electrode preoxidation with triethylamine (TEA) as ac o-reactant. The lmethionine-stabilized AuNCs resulted in ar ecordh igh ECL yield of 66 %. This strategy was successfully extended to other AuNCs,a nd it is more effective for ligand shells that allow more effective electron transfer.I na ddition, excitation of the pre-oxidized ECL required al ower potential than conventional methods,a nd no additional instrument was required. This work opens avenues for solving achallenging problem of AuNC-based ECL probes and enriches fundamental understanding,greatly broadening their potential applications.

Cysteine Modification of Glutathione-Stabilized Au Nanoclusters to Red-Shift and Enhance the Electrochemiluminescence for Sensitive Bioanalysis

“…24,25 Moreover, their ECL emission wavebands and efficiency can be regulated by changing the stabilizer capped on their surface and accelerating the charge transfer among the electrochemical process with a electrosensitizer such as Cu 2 O. 26 By covalently binding N,N-diethylethylenediamine to lipoic acid-stabilized AuNCs 20 or preoxidizing Lmethionine (Met)-stabilized AuNCs (Met-AuNCs), 21 the ECL performance can be improved. A doping-in-growth way has also been proposed to enhance the ECL performance and regulate the emission waveband of AuNCs.…”

“…The ECL of luminol, Ru­(bpy) 3 2+ , and nanomaterials such as CdSe, g-C 3 N 4 , and polymer dots (P-dots) is primarily located in the visible region. Although some ECL luminophores with low emission potential or near-infrared (NIR) band , have been presented for decreasing the interference and photochemical damage in bioassay, their ECL efficiency is still limited owing to the depressed through-bond charge transfer in the electronic process and the enhanced nonradiative relaxation of excited states during the energy transition. , In recent years, some metal nanoclusters (NCs) with admirable physicochemical properties have been found to show good ECL performance. − Especially, AuNCs have been successfully proved to be a kind of biocompatible and eco-friendly NIR ECL luminophores. , Moreover, their ECL emission wavebands and efficiency can be regulated by changing the stabilizer capped on their surface and accelerating the charge transfer among the electrochemical process with a electrosensitizer such as Cu 2 O . By covalently binding N , N -diethylethylenediamine to lipoic acid-stabilized AuNCs or preoxidizing l -methionine (Met)-stabilized AuNCs (Met-AuNCs), the ECL performance can be improved.…”

Gold Nanocluster Probe-Based Electron-Transfer-Mediated Electrochemiluminescence Sensing Strategy for an Ultrasensitive Copper Ion Detection

“…The ECL peak of OM-AuNCs is at approximately 800 nm, which corresponded to our reported result (Figure S4). However, in this wavelength range, the absorption of Cu 2+ was almost negligible at such a low concentration. Thus, we could exclude that the RET played a major role in the ECL quenching of the OM-AuNC emission.…”

“…It is urgent to construct a convenient, rapid, and accurate method for the detection of trace transitional metal ions in environmental and biological processes. , Met-AuNCs were synthesized according to our previously reported method (Figures S1 and S2). The ECL performance of OM-AuNCs/TEA system regulated by Cu 2+ was studied in detail. Compared with Met-AuNC/GCE (Figure A, curve a), a 24.3-fold enhancement in ECL intensity was observed after the pre-oxidation treatment owing to the valence effect (Figure A (curve b), B (curve a)).…”

“…The OM-AuNC/GCE was prepared in accordance with the method we reported previously . Briefly, the GCE was polished and sonicated according to the reported work .…”