High-Efficient Electrochemiluminescence of Au Nanoclusters Induced by the Electrosensitizer Cu2O: The Mechanism Insights from the Electrogenerated Process

Herein, a novel Au nanoclusters/Cu2O (Au NCs/Cu2O) heterostructure exhibited exceptionally strong electrochemiluminescence (ECL) emission, in which the p-type semiconductor Cu2O was defined as the electrosensitizer to provide the electrogenerated holes for rapidly transferring the electrogenerated hot electrons of Au NCs. Thus, the fast charge transfer of Au NCs/Cu2O was achieved by the electrosensitizer compared to the sluggish one via intramolecular covalent bond charge transfer of traditional Au NCs, resulting in a greatly higher ECL efficiency (63.8%) than that of pure Au NCs (2.7%) versus the standard [Ru(bpy)3]2+. It solved one main challenge of electrochemiluminophore-based metal NCs: high efficiency with energic charge-transport kinetics. As a proof of concept, Au NCs/Cu2O was successfully employed in an ultrasensitive ECL biosensing platform for determining the biological antioxidant glutathione with a limit of detection (LOD) as low as 6.3 pM. The heterostructure as an ECL emitter is a very promising start for guiding the rational design of efficient electrochemiluminophores in intense light-emitting devices and high-definition ECL imaging.