Reductive-Oxidation Co-reactant-Induced Electrogenerated Chemiluminescence of Gold Nanocluster Isomers

Electrogenerated chemiluminescence of Au21hcp,0 and Au21fcc,0 nanocluster isomers in the presence of benzoyl peroxide (BPO), as an oxidizing co-reactant, was investigated. A near-infrared (NIR) ECL emission at 838 nm (Au21hcp,0*) and 842 nm (Au21fcc,0*) is observed. The ECL efficiency of Au21hcp,0/BPO and Au21fcc,0/BPO was estimated to be 3.13% and 0.12%, respectively, versus the Ru(bpy)32+/BPO system. Interestingly, the ECL efficiency of Au21hcp,0/BPO is almost 26-fold higher than that of Au21fcc,0/BPO. This observation agrees well with the previously reported ECL efficiency of Au21 isomers in the presence of tripropylamine (TPrA). However, the ECL efficiencies of Au21hcp,0 and Au21fcc,0 in the presence of BPO are lower than those of TPrA, which could be related to the bulkiness of the BPO radical versus the TPrA radical as well as their oxidation and reduction power.