Resolving the Growth of 3D Colloidal Nanoparticle Superlattices by Real-Time Small-Angle X-ray Scattering

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• 作者：Chenguang Lu ; Austin J. Akey ; Clayton J. Dahlman ; Datong Zhang ; Irving P. Herman
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：November 14, 2012
• 年：2012
• 卷：134
• 期：45
• 页码：18732-18738
• 全文大小：602K
• 年卷期：v.134,no.45(November 14, 2012)
• ISSN：1520-5126

文摘

The kinetics and intricate interactions governing the growth of 3D single nanoparticle (NP) superlattices (SLs, SNSLs) and binary NP SLs (BNSLs) in solution are understood by combining controlled solvent evaporation and in situ, real-time small-angle X-ray scattering (SAXS). For the iron oxide (magnetite) NP SLs studied here, the larger the NP, the farther apart are the NPs when the SNSLs begin to precipitate and the closer they are after ordering. This is explained by a model of NP assembly using van der Waals interactions between magnetite cores in hydrocarbons with a 21 zJ Hamaker constant. When forming BNSLs of two different sized NPs, the NPs that are in excess of that needed to achieve the final BNSL stoichiometry are expelled during the BNSL formation, and these expelled NPs can form SNSLs. The long-range ordering of these SNSLs and the BNSLs can occur faster than the NP expulsion.