UNEXPECTED PHOTOLUMINESCENCE ENHANCEMENT OF RED-EMITTING CdTe QUANTUM DOTS BY Cu2+ IONS

Abstract

Size-dependent reactivity of semiconductor quantum dots (QDs) is of importance to deploy QDs to diverse applications such as photocatalysts, chemosensors, and QDs synthesis. Herein, we studied the effects of Cu²⁺ on the absorption and photoluminescent properties of water-soluble CdTe QDs in order to demonstrate the application potential of CdTe QDs as a photoluminescent sensor for Cu²⁺ detection. Unexpectedly, while the photoluminescence (PL) of small CdTe QDs, such as green or yellow emitting CdTe QDs changed slightly with increasing Cu²⁺ concentration from 10^-8 M to 10^-5 M the PL intensity of red-emitting QDs increased by about 3.3 times. In the higher concentration regime, PL intensity of the small QDs decreased while that of red-emitting QDs unchanged with Cu²⁺. Out results advise the uses of CdTe QDs of suitable size for Cu²⁺ detection in the aqueous medium.