Mandal, Abhijit and Dandapat, Anirban and De, Goutam (2012) Magic sized ZnS quantum dots as a highly sensitive and selective fluorescence sensor probe for Ag+ ions. Analyst, 137 (3). pp. 765-772. ISSN 0003-2654

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A green and simple chemical synthesis of magic sized water soluble blue-emitting ZnS quantum dots (QDs) has been accomplished by reacting anhydrous Zn acetate, sodium sulfide and thiolactic acid (TLA) at room temperature in aqueous solution. Refluxing of this mixture in open air yielded ZnS clusters of about 3.5 nm in diameter showing very strong and narrow photoluminescence properties with long stability. Refluxing did not cause any noticeable size increment of the clusters. As a result, the QDs obtained after different refluxing conditions showed similar absorption and photoluminescence (PL) features. Use of TLA as a capping agent effectively yielded such stable and magic sized QDs. The as-synthesized and 0.5 h refluxed ZnS QDs were used as a fluorescence sensor for Ag+ ions. It has been observed that after addition of Ag+ ions of concentration 0.5-1 mu M the strong fluorescence of ZnS QDs was almost quenched. The quenched fluorescence can be recovered by adding ethylenediamine to form a complex with Ag+ ions. The other metal ions (K+, Ca2+, Au3+, Cu2+, Fe3+, Mn2+, Mg2+, Co2+) showed little or no effect on the fluorescence of ZnS QDs when tested individually or as a mixture. In the presence of all these ions, Ag+ responded well and therefore ZnS QDs reported in this work can be used as a Ag+ ion fluorescence sensor.

Item Type: Article
Subjects: Engineering Materials
Divisions: Nano-Structured Materials
Depositing User: Bidhan Chaudhuri
Date Deposited: 04 Jun 2012 08:07
Last Modified: 04 Jun 2012 08:07

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