Sulfonic Acid-Functionalized Tetraphenylethylene-Amplified Electrochemiluminescence by Regulating π–π Interaction

The electrochemiluminescence (ECL) effectiveness of the tris(bipyridine) ruthenium(II) (Ru(bpy)32+) system is hampered by aggregation-caused quenching (ACQ) in optoelectronic systems as a result of π–π accumulation of the aromatic ring structure. In this work, a negatively charged tetraphenylvinyl molecule (TPE-2SO3Na, TPE-4SO3Na) was synthesized to modify the electrode interface, and the π–π accumulation between Ru(bpy)32+ molecules was transformed into the π–π interaction between Ru(bpy)32+ and TPE molecules. Interestingly, the ECL signal intensity of the Ru(bpy)32+-tripropylamine (TPA) system in the presence of TPE-2SO3Na was increased by about 15 times due to the π–π action and electrostatic action. In comparison with traditional physical packaging with porous zeolites, metal–organic frameworks (MOFs), and covalent organic frameworks (COFs), the fabricated electrode interface modification strategy was simple and efficient to avoid π–π accumulation in aqueous solutions. Our success will inspire other researchers to investigate the supramolecular interaction (π–π interaction, electrostatic interaction, hydrophilic interaction, and host–guest interaction) at the electrode interface to amplify the ECL intensities of Ru(bpy)32+.