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

Herein, a novel Au nanoclusters/Cu 2 O (Au NCs/Cu 2 O) heterostructure exhibited exceptionally strong electrochemiluminescence (ECL) emission, in which the p-type semiconductor Cu 2 O 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/Cu 2 O 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/Cu 2 O 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.