Experimental Evaluation of Kinetic and Thermodynamic Reaction Parameters of Colloidal Nanocrystals

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• 作者：Eric M. Brauser ; Trevor D. Hull ; John D. McLennan ; Jacqueline T. Siy ; Michael H. Bartl
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：June 14, 2016
• 年：2016
• 卷：28
• 期：11
• 页码：3831-3838
• 全文大小：396K
• 年卷期：0
• ISSN：1520-5002

文摘

The unique properties of colloidal semiconductor nanocrystals, or quantum dots, have attracted enormous interest in a wide range of applications, including energy, lighting, and biomedical fields. However, widespread implementation is hampered by the difficulty of developing large-scale and inexpensive synthesis routes, mainly due to our limited knowledge of formation reaction parameters. We report here a simple yet powerful method to experimentally determine critically important reaction parameters such as rate constants, activation barriers, equilibrium constants and reaction enthalpies. This method was applied to wurtzite cadmium selenide nanocrystals, yielding activation energies for growth and dissolution of 14 ± 6 kJ mol^–1 and 27 ± 8 kJ mol^–1, respectively, and a reaction enthalpy for nanocrystal growth of −15 ± 7 kJ mol^–1. Moreover, the Gibbs free energy for growth was found to be negative at low temperatures, whereas dissolution becomes the spontaneous process above 150 °C.