Cademartiri Ludovico, Ghadimi Arya, Ozin Geoffrey A
Materials Chemistry Research Group, Lash Miller Chemical Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, Canada.
Acc Chem Res. 2008 Dec;41(12):1820-30. doi: 10.1021/ar800158d.
Nanocrystal superstructures are increasingly becoming a subject of intense study. Such materials could constitute a new class of nanocomposites of designed structure, of homogeneous composition, and with unique properties. New phenomena are observed in these materials because of the interaction at such diminutive length scales. A common problem in the development of devices relying on colloidal nanocrystal assemblies is that the individual nanocrystal building blocks require organic molecules to control their size. These ligands are responsible for the colloidal stability of the individual nanocrystal building blocks and are thus necessary for their solution processibility. Because of the ligands' incompatibility with many solid state applications, it is important to develop post-processing techniques that mildly remove them from these nanocomposites, while maintaining the size-dependent properties of the building blocks. This Account highlights a new strategy, nanocrystal plasma polymerization (NPP), for processing colloidal nanocrystal assemblies. This technique exposes the nanocomposite to a mild air plasma and allows for the removal of the nanocrystals' capping ligands while preserving their size-dependent and material properties. As a result, the process yields a nearly all-inorganic flexible solid-state material with unprecedented characteristics. We describe early experiments, in which NPP was used to create arbitrarily complex 1D, 2D, and 3D inorganic free-standing architectures entirely composed of nanocrystals, as well as future directions and challenges. We expect this platform will be useful for the design of new materials and will be a valuable new addition to the nanoscientist's toolbox.
纳米晶体超结构正日益成为深入研究的对象。这类材料可能构成一类具有设计结构、成分均匀且具有独特性能的新型纳米复合材料。由于在如此微小的长度尺度上存在相互作用，在这些材料中观察到了新现象。依赖胶体纳米晶体组件的器件开发中的一个常见问题是，单个纳米晶体构建块需要有机分子来控制其尺寸。这些配体负责单个纳米晶体构建块的胶体稳定性，因此对于它们的溶液可加工性是必需的。由于配体与许多固态应用不相容，开发后处理技术以温和地从这些纳米复合材料中去除它们，同时保持构建块的尺寸依赖性特性非常重要。本综述重点介绍了一种用于处理胶体纳米晶体组件的新策略——纳米晶体等离子体聚合（NPP）。该技术将纳米复合材料暴露于温和的空气等离子体中，能够去除纳米晶体的封端配体，同时保留其尺寸依赖性和材料特性。结果，该过程产生了一种具有前所未有的特性的几乎全无机的柔性固态材料。我们描述了早期实验，其中NPP被用于创建完全由纳米晶体组成的任意复杂的一维、二维和三维无机独立结构，以及未来的方向和挑战。我们预计这个平台将有助于新材料的设计，并将成为纳米科学家工具包中有价值的新补充。
