Autocatalytic Electrochemiluminescence
Year: 2025
Type: article
Abstract: Electrochemiluminescence (ECL) is a powerful analytical technique that generates light through electrochemically induced reactions, enabling ultrasensitive biosensing and imaging of submicrometric objects. Conventional ECL systems, such as those using Ru(bpy) 3 2 ⁺ and tri‐ n ‐propylamine (TPrA), require high applied potentials (oxidation at ∼1.4 V versus Ag/AgCl), leading to electrode surface modification and parasitic reactions. Herein, we present a novel autocatalytic ECL mechanism that drastically lowers the triggering potential to −0.2 V by exploiting the synergistic interplay between oxalate (C 2 O 4 2− ) and peroxydisulfate (S 2 O 8 2− ) radicals, mediated by Ru(NH 3 ) 6 3+ reduction. This system generates ECL without direct oxidation of the luminophore, but instead through a mild reduction process, relying on homogeneous radical reactions (SO 4 • − and CO 2 • − ) to populate the Ru(bpy) 3 2 ⁺* excited state. Experimental investigation at different Ru(NH 3 ) 6 3+ /S 2 O 8 2 − /C 2 O 4 2 − concentration ratios, backed by finite element simulations, demonstrates the autocatalytic cycle's capability of exciting luminophores with a bandgap as high as 2.77 eV (blue‐emitting Ir(III) complex), while also showing a more stable ECL emission and achieving an emitting layer as thick as ∼4.8 ± 0.2 µm. These findings establish a low‐potential ECL pathway with a large emitting layer, extending the applicability of such nontoxic coreactants—historically limited by their short‐lived radicals—and potentially paving the way for new frontiers in ECL.
Institutions: University of Bologna, Centre National de la Recherche Scientifique, Université Paris Cité, Interfaces Traitements Organisation et Dynamique des Systèmes, Sorbonne Université, Chimie de la Matière Condensée de Paris, Université de Bordeaux, Institut des Sciences Moléculaires, Institut Polytechnique de Bordeaux, Deakin University
Language: English
Subfield: Electrochemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7117664047