Surface Charge Control of Quantum Dot Blinking

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• 作者：Steven D. Quinn ; Aidan Rafferty ; Emma Dick ; Michael J. Morten ; Fraser J. Kettles ; Chloe Knox ; Mark Murrie ; Steven W. Magennis
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：September 1, 2016
• 年：2016
• 卷：120
• 期：34
• 页码：19487-19491
• 全文大小：338K
• 年卷期：0
• ISSN：1932-7455

文摘

A characteristic property of colloidal semiconductor nanocrystal quantum dots (QDs) is their emission intermittency. Although a unifying theory of QD photoprocesses remains elusive, the importance of charged states is clear. We now report a new approach to directly study the role of surface charge on QD emission by adding metal ions to individual, core-only QDs immobilized in aqueous solution in an agarose gel. The CdTe QDs show very stable emission in the absence of metal ions but a dramatic and reversible increase in blinking due to the presence of trivalent metal ions. Our results support a charge-separation model, in which the major blinking pathway is the surface trapping of electrons; transiently bound metal ions close to the QD surface enhance this process.