Cathodic electrochemiluminescence from self-designed near-infrared-emitting CdTe/CdS/ZnS quantum dots on bare Au electrode

Cathodic electrochemiluminescence (ECL) from self-designed near-infrared (NIR)-emitting CdTe/CdS/ZnS quantum dots (QDs) on bare Au electrode in aqueous solution was studied. Strong and stable ECL signals at − 1.25 V with an onset potential of − 0.98 V produced by the highly effective electron-transfer reactions between electron-injected CdTe/CdS/ZnS QDs and reduced S2O82− are observed. Passivation of the QD surfaces with ZnS shell increased ECL intensity by 9 times when compared to CdTe/CdS QDs. The good correspondence of the ECL emission peak with the photoluminescence results suggested the surface states of the QDs had been largely passivated by ZnS shell. Furthermore, the effects of pH, buffer solutions, electrode materials and concentrations of K2S2O8 on ECL intensity were investigated, and a possible ECL mechanism was also proposed.