Lawrence Livermore National Laboratory , 7000 East Avenue, Livermore, California 94550, United States.
University of California Los Angeles , Los Angeles, California 90095, United States.
Nano Lett. 2017 Jun 14;17(6):3862-3869. doi: 10.1021/acs.nanolett.7b01323. Epub 2017 May 25.
Nanocrystal superlattices are typically fabricated by either solvent evaporation or destabilization methods that require long time periods to generate highly ordered structures. In this paper, we report for the first time the use of electric fields to reversibly drive nanocrystal assembly into superlattices without changing solvent volume or composition, and show that this method only takes 20 min to produce polyhedral colloidal crystals, which would otherwise need days or weeks. This method offers a way to control the lattice constants and degree of preferential orientation for superlattices and can suppress the uniaxial superlattice contraction associated with solvent evaporation. In situ small-angle X-ray scattering experiments indicated that nanocrystal superlattices were formed while solvated, not during drying.
纳米晶体超晶格通常通过溶剂蒸发或失稳方法来制备，这些方法需要很长时间才能生成高度有序的结构。在本文中，我们首次报道了使用电场将纳米晶体组装成超晶格，而不改变溶剂体积或组成，并且表明这种方法仅需 20 分钟即可生产多面体胶体晶体，而这在其他情况下则需要数天或数周的时间。该方法提供了一种控制超晶格晶格常数和择优取向的方法，并且可以抑制与溶剂蒸发相关的单轴超晶格收缩。原位小角 X 射线散射实验表明，纳米晶体超晶格是在溶剂化过程中形成的，而不是在干燥过程中形成的。
