School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Nat Nanotechnol. 2013 Jun;8(6):426-31. doi: 10.1038/nnano.2013.85. Epub 2013 Jun 2.
Colloidal nanocrystals exhibit a wide range of size- and shape-dependent properties and have found application in myriad fields, incuding optics, electronics, mechanics, drug delivery and catalysis, to name but a few. Synthetic protocols that enable the simple and convenient production of colloidal nanocrystals with controlled size, shape and composition are therefore of key general importance. Current strategies include organic solution-phase synthesis, thermolysis of organometallic precursors, sol-gel processes, hydrothermal reactions and biomimetic and dendrimer templating. Often, however, these procedures require stringent experimental conditions, are difficult to generalize, or necessitate tedious multistep reactions and purification. Recently, linear amphiphilic block co-polymer micelles have been used as templates to synthesize functional nanocrystals, but the thermodynamic instability of these micelles limits the scope of this approach. Here, we report a general strategy for crafting a large variety of functional nanocrystals with precisely controlled dimensions, compositions and architectures by using star-like block co-polymers as nanoreactors. This new class of co-polymers forms unimolecular micelles that are structurally stable, therefore overcoming the intrinsic instability of linear block co-polymer micelles. Our approach enables the facile synthesis of organic solvent- and water-soluble nearly monodisperse nanocrystals with desired composition and architecture, including core-shell and hollow nanostructures. We demonstrate the generality of our approach by describing, as examples, the synthesis of various sizes and architectures of metallic, ferroelectric, magnetic, semiconductor and luminescent colloidal nanocrystals.
胶体纳米晶体表现出广泛的尺寸和形状依赖性性质，并已在众多领域得到应用，包括光学、电子学、力学、药物输送和催化等领域。因此，能够简单方便地生产具有可控尺寸、形状和组成的胶体纳米晶体的合成方法具有重要的普遍意义。目前的策略包括有机溶液相合成、有机金属前体的热解、溶胶-凝胶过程、水热反应以及仿生和树状大分子模板。然而，这些方法通常需要严格的实验条件，难以推广，或者需要繁琐的多步反应和纯化。最近，线性两亲嵌段共聚物胶束已被用作模板来合成功能性纳米晶体，但这些胶束的热力学不稳定性限制了这种方法的应用范围。在这里，我们报告了一种使用星形嵌段共聚物作为纳米反应器来制备具有精确控制尺寸、组成和结构的各种功能纳米晶体的通用策略。这种新型共聚物形成结构稳定的单分子胶束，从而克服了线性嵌段共聚物胶束的固有不稳定性。我们的方法能够方便地合成有机溶剂和水溶性的近单分散纳米晶体，具有所需的组成和结构，包括核壳和空心纳米结构。我们通过描述各种尺寸和结构的金属、铁电、磁性、半导体和发光胶体纳米晶体的合成，证明了我们方法的通用性。
