Quantifying Quantum Dots through F枚rster Resonant Energy Transfer

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• 作者：Preston T. Snee ; Christina M. Tyrakowski ; Leah E. Page ; Adela Isovic ; Ali M. Jawaid
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：October 13, 2011
• 年：2011
• 卷：115
• 期：40
• 页码：19578-19582
• 全文大小：840K
• 年卷期：v.115,no.40(October 13, 2011)
• ISSN：1932-7455

文摘

Semiconductor nanocrystals (NCs or quantum dots) have significant potential for use in a variety of applications from renewable energy generation to biological imaging. Modern methods of colloidal synthesis can be used to create crystalline materials with tight size distributions; this assures high quantum yields and narrow emission profiles in the case of direct-bandgap semiconductors. The optical properties of NCs may also be tuned with size due to quantum confinement effects. Quantum confinement also creates problems when characterizing nanomaterials; specifically, the absorptivity of a sample is a function of the size and structure of the quantum dots. We demonstrate here a simple method for determining the molar absorptivity of aqueous CdSe/CdZnS NCs through F枚rster resonant energy transfer. Energy transfer from NC donors to dye acceptors was measured and modeled using standard F枚rster theory incorporating Poissonian statistics to calculate the acceptor/donor ratio leading to a direct determination of the NC concentration. This process is significantly more simple than standard methods for calculating the size-dependent Beer鈥檚 law coefficient of nanomaterials and can be applied to heterogeneous quantum confined systems. The results also yield surprising insight into the internal structure of water-soluble polymer-coated core/shell quantum dots.