期刊
JOURNAL OF PHYSICAL CHEMISTRY C
卷 125, 期 28, 页码 15396-15404出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.jpcc.1c02357
关键词
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资金
- UGC
- SERB, India
- SERB
- NCPRE
The study demonstrates the potential of aqueous polyethyleneimine-capped CdS quantum dots for rapid detection of toxic metal ion Pb2+, with hot electron transfer playing a crucial role in fluorescence quenching.
The prospect of aqueous polyethyleneimine-capped CdS quantum dots (QDs), in toxic metal-ion sensing, has been explored. Pb2+ binds strongly to the surface of the QDs facilitating ultrafast electron transfer. As a result, severe (similar to 90%) PL quenching is observed. Hot electron transfer plays an important role in the quenching process, as is elucidated by anticorrelation between the magnitude of ground-state bleach of the QDs and the concentration of Pb2+ ions, as well as the concurrent decrease in bleach rise time. A second major contribution is from electron transfer from conduction band edge, with a rate constant of 1.45 x 10(11) s(-1). Selectivity in this turn-off sensing process is governed by the exergonicity, quality of QD surface, nature of capping ligand, and its metal-ion binding properties. Engineering these factors is crucial for the development of QD-based selective and efficient metal-ion sensors.
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