Kinetically Driven Cadmium Chalcogenide Nanorod Growth Fed by Local Cluster Aggregates
Kinetically Driven Cadmium Chalcogenide Nanorod Growth Fed by Local Cluster Aggregates
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DOI：
10.1021/acs.jpcc.0c02730
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发表时间：
2020-06-11
影响因子：
3.7
通讯作者：
Boldt, Klaus
中科院分区：
文献类型：
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作者：
Fischli, Danja;Enders, Florian;Boldt, Klaus
导致形成各向异性胶体半导体纳米晶体的对称性破缺过程是理解成核和生长物理机制的重要问题。假设纳米棒的一维生长是在高浓度单体的反应限制控制下发生的，该单体优先在具有最高能量和表面配体钝化最少的晶面上发生反应。在这项研究中，研究表明，CdS 纳米棒在 CdSe 颗粒上的晶种生长不是假设单体在反应溶液中均匀分布，而是由充当局部单体库的一维反应中间体的形成驱动的。这些导致成核物质的不均匀分布的热点，保证了纳米棒仅在一个方向上的快速沉积和一维生长。因此，在有利于形成瞬态、亚稳态中间体的条件下进行各向异性颗粒生长反应会导致颗粒具有更高的长径比和更好的机械反应控制。
The process of symmetry breaking that leads to the formation of anisotropic, colloidal semiconductor nanocrystals is an important issue for understanding the physical mechanism of nucleation and growth. One-dimensional growth of nanorods is assumed to occur under reaction-limited control at a high concentration of monomer, which preferentially reacts at the crystal facet that has the highest energy and least passivation by surface ligands. In this study, it is shown that instead of assuming a homogeneous distribution of monomer in the reaction solution, the seeded growth of CdS nanorods on CdSe particles is driven by the formation of one-dimensional reaction intermediates that act as local monomer reservoirs. These result in heterogeneously distributed hotspots of the nucleating species that guarantees fast deposition and one-dimensional growth of the nanorod exclusively in one direction. Thus, performing anisotropic particle growth reactions under conditions that favor formation of transient, metastable intermediates lead to particles with a higher aspect ratio and better mechanistic reaction control.