Electrogenerated Radicals Boosting Chemiluminescence of CdSe/CdS/ZnS Quantum Dots

ABSTRACT We report in this work highly efficient, temporally stable, and multicolor chemiluminescence of CdSe/CdS/ZnS quantum dots (QDs) boosted by radicals that are in situ electrogenerated near the electrode surface. Typically, electrochemical oxidation of tri‐ n ‐propylamine (TPrA), a tertiary amine, generates radical cation (TPrA •+ ) and radical (TPrA • ). Then, TPrA • and TPrA •+ sequentially inject an electron and a hole to the valence and conduction bands of a QD to populate the excited state (QD*). In this pathway, a negatively charged QD (QD − ) is formed as the key intermediate, instead of fragile positively charged QD + , thus producing highly stable and efficient luminescence. Moreover, this pathway is also identical to the so‐called low‐oxidation‐potential electrochemiluminescence route of the gold standard luminophore, tris(2,2′‐bipyridyl)ruthenium (Ru(bpy) 3 2+ ), and therefore fully fit for microbead‐based bioassays. Considering their high emission efficiency (∼5 times higher than Ru(bpy) 3 2+ under same condition), narrow emission bands and tunable wavelengths, these QDs hold great promise as luminophores in ultrasensitive and multiplexed microbead‐based bioassays.