Balancing the Concentrations of Redox Species to Improve Electrochemiluminescence by Tailoring the Symmetry of the AC Voltage

Abstract

We propose an effective methodology to improve the brightness of Ru(bpy) 3 2 + -based electrochemiluminescence (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 duty ratio) 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 , respectively. When the duty ratio is 40 %, a luminance of approximately 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 a maximum luminance of approximately 207 Cd/m 2 at 150 Hz. Overall, this work elucidates the 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.

Functional Ion Gels: Versatile Electrolyte Platforms for Electrochemical Applications

“…For example, by adjusting the characteristics of the input AC voltage wave (e.g., duty ratio and frequency), a balanced concentration of redox species was induced and the brightness of the ECL device was improved. 8 Inorganic nanoparticles (NPs) (e.g., titanium dioxide (TiO 2 )) can be introduced to promote electron transfer between redox materials and improve the lifetimes of the ECL devices. 105 The application of a square wave including the resting period is another option to achieve higher device stability, by which the appearance of undesired side reactions can be reduced by replenishing the reaction volume near the electrode with fresh ECL materials contained in the bulk electrolyte.…”

Gold Nanoparticles/Mo2C/MoO2-Modified Electrodes for Nucleic Acid Detection through CRISPR/Cas12a Photoelectrochemical Assay

“…The cyclic voltammetry (CV) behavior of p -AP and Ru­(bpy) 3 Cl 2 shows that the redox peak of the p -AP/ p -quinonimine ( p -QI) redox couple appears at about −0.02 to +0.15 V (red curve), whereas the redox peak of the Ru­(bpy) 3 2+ /Ru­(bpy) 3 3+ redox couple appears at about 0.99–1.05 V (blue curve; Figure A). p -AP has a strong oxidation peak at approximately 0.15 V with higher current intensity, whereas Ru­(bpy) 3 2+ indicates an oxidation peak at about 1.05 V with indistinct current intensity. The oxidation potential of p -AP is lower than that of Ru­(bpy) 3 2+ , indicating easier oxidation of p -AP than Ru­(bpy) 3 2+ .…”

“…2+ indicates an oxidation peak at about 1.05 V 32 with indistinct current intensity. The oxidation potential of p-AP is lower than that of Ru(bpy) 3 2+ , indicating easier oxidation of p-AP than Ru(bpy) 3 2+ .…”

Electrochemiluminescence for Characterizing the Polymerization Process during Graphitic Carbon Nitride Synthesis

“…Electrochemiluminescence (ECL) is the process whereby electrogenerated species undergo chemical reaction to form excited state that emits light . ECL is widely used not only in clinical and environmental detection and display filed, but also as an effective tool to analyze the surface state of nanomaterials . Our previous works demonstrate that the ECL intensity and stability of g‐CN nanosheets (CNNS) film is highly dependent on the electron transport efficiency of the film .…”