Cation Exchange-Based Facile Aqueous Synthesis of Small, Stable, and Nontoxic Near-Infrared Ag₂Te/ZnS Core/Shell Quantum Dots Emitting in the Second Biological Window

Chi Chen ‡, Xuewen He †, Li Gao †, and Nan Ma *†‡ （马楠）

^† The Key Lab of Health Chemistry and Molecular Diagnosis of Suzhou, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, 215123, P. R. China

^‡ CAS Key Laboratory of Health Informatics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, P. R. China

ACS Appl. Mater. Interfaces 2013, 5, 1149–1155.

Facile aqueous synthesis of near-infrared Ag₂Te quantum dots (QDs) and Ag₂Te/ZnS core/shell QDs emitting in the second biological window is reported. The QD synthesis is based on a straightforward cation exchange process between CdTe QDs and Ag⁺ ions conducted in aqueous solution. The prepared Ag₂Te QDs possess near-infrared emission ranging from 900 to 1300 nm and a quantum yield up to 2.1%. A ZnS shell was grown on the Ag₂Te QD to further enhance the photoluminescence intensity with a quantum yield of 5.6%. These Ag₂Te/ZnS core/shell QDs possess robust colloidal stability and photostability with minimum photoluminescence fluctuation upon incubation for 72 h in biological buffer or continuous laser excitation for 120 min. Also, These QDs possess small hydrodynamic size ( 7.6 nm) and are non-cytotoxic to human cells, which is ideal for optical bioimaging in the second biological window.

链接： //pubs.acs.org/doi/abs/10.1021/am302933x