Symmetry in Seeded Metal Nanocrystal Growth
Symmetry in Seeded Metal Nanocrystal Growth
复制标题
DOI：
10.1021/accountsmr.1c00077
复制
发表时间：
2021-07
影响因子：
14.6
通讯作者：
S. Skrabalak
中科院分区：
文献类型：
--
作者：
S. Skrabalak
对称性是我们周围世界的结构和功能的基础，也被现代纳米材料所捕获，在那里改变超晶格中纳米结构单元的对称性或粒子间间距和方向可以赋予新的功能。然而，纳米晶体的合成和组装在很大程度上限于简单的组成和结构。它仍然是一个巨大的挑战，以实现纳米晶体的组成和结构的复杂性，同时保持其使用所需的单分散性。ThisAccounting说明通过最近的例子，种子的方法，使合成的组成和结构复杂的多金属晶体与定义和可预测的对称性，在等离子体激元和催化的应用。这种结果的出现是因为异质成核的势垒（即，晶种）的成核速率低于均匀成核，在均匀成核中，晶种可作为复杂结构和晶相生长的优先位置。我们的分析开始考虑金属从单晶种子的不同形状和对称性，其中吸附原子除了种子相对于它们的扩散在种子的动力学过度生长占所表示的形状。然后将这些结果与来自具有不同内部结构（即，平面缺陷），其中讨论了晶粒尺寸与体积应变能和表面能之间的关系。从这个分析的一个主要发现是，通常潜在的对称性的种子可以预测转移到最终的晶体在过度生长过程中。这一发现的结果是具有类似于雪晶的不同层次的晶体以及具有复杂组成的纳米晶体（例如，四元纳米颗粒）。然而，种子生长有一些微妙的方面，它们为那些与原始种子相比以受控方式降低了对称性的例子铺平了道路。正如我们所发现的，金属前体和封端剂的浓度都可以影响在过度生长期间对称性是否转移或降低。从我们的实验室的例子将被放置在上下文中的其他报告的对称性破缺的策略。正如将要讨论的那样，理解在籽晶生长过程中什么条件有利于对称性保持而不是对称性降低是获得下一代晶体形式的核心。该帐户总结概述了与形成纳米级异质结构相关的合成挑战，这些异质结构具有在给定的衬底内精确的3-D放置不同材料以及在不同材料域和界面工程中的面控制。我们设想通过区域选择性和化学选择性种子合成来应对这些挑战，本文概述了这些挑战的基础。
ConspectusSymmetry underpins the structure and function of the world around us and is also captured in modern nanomaterials, where changing the symmetry of a nanocrystal or the interparticle spacing and orientation of nanocrystal building blocks in a superlattice can give new function. However, the synthesis and assembly of nanocrystals have been limited largely to simple compositions and structures. It remains a grand challenge to achieve nanocrystals with compositional and structural complexity while maintaining the monodispersity required for their use. ThisAccountwill illustrate through recent examples that seeded methods enable the synthesis of compositionally and structurally complex multimetallic crystals with defined and predictable symmetries for applications in plasmonics and catalysis. This outcome arises because the barrier for heterogeneous nucleation (i.e., seeded) is lower than that of homogeneous nucleation, where seeds can serve as preferential sites for the growth of complex structures and crystal phases. Our analysis begins by considering metal overgrowth from single-crystalline seeds of different shapes and symmetries, where the kinetics of adatom addition to seeds relative to their diffusion across seeds accounts for the expressed nanocrystal shapes. These results are then compared to overgrowth from seeds with different internal structures (i.e., planar defects), where the relationships between nanocrystal size and volumetric strain energy and surface energy are discussed. A major finding from this analysis is that often the underlying symmetry of seeds can be predictably transferred to the final crystals during overgrowth processes. Consequences of this finding are the predictable syntheses of crystals with different hierarchies akin to snowcrystals as well as nanocrystals with complex compositions (e.g., quaternary nanoparticles). Yet, there are subtle aspects to seeded growth that pave a path toward examples where nanocrystal symmetry has been reduced compared to the original seeds in a controlled manner. As we found, both the concentrations of metal precursors and capping agents can impact whether symmetry is transferred or reduced during overgrowth. Examples from our laboratory will be placed in context to other reported strategies for symmetry breaking. As will be argued, understanding what conditions favor symmetry preservation versus symmetry reduction during seeded crystal growth is central to accessing next-generation crystal forms. TheAccountconcludes by outlining synthetic challenges associated with forming nanoscale heterostructures with precise 3-D placement of different materials within a given nanocrystal as well as facet control within different material domain and interface engineering. We envision meeting these challenges through regioselective and chemoselective seeded syntheses for which a foundation is outlined herein.