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Colloidal Dual-Diameter and Core-Position-Controlled Core/Shell Cadmium Chalcogenide Nanorods
ACS Nano ( IF 15.8 ) Pub Date : 2017-11-16 00:00:00 , DOI: 10.1021/acsnano.7b06542
Dahin Kim 1 , Young Kuk Lee 2 , Dongkyu Lee 1 , Whi Dong Kim 1 , Wan Ki Bae 3 , Doh C. Lee 1
Affiliation  

To capitalize on shape- and structure-dependent properties of semiconductor nanorods (NRs), high-precision control and exquisite design of their growth are desired. Cadmium chalcogenide (CdE; E = S or Se) NRs are the most studied class of such, whose growth exhibits axial anisotropy, i.e., different growth rates along the opposite directions of {0001} planes. However, the mechanism behind asymmetric axial growth of NRs remains unclear because of the difficulty in instant analysis of growth surfaces. Here, we design colloidal dual-diameter semiconductor NRs (DDNRs) under the quantum confinement regime, which have two sections along the long axis with different diameters. The segmentation of the DDNRs allows rigorous assessment of the kinetics of NR growth at a molecular level. The reactivity of a terminal facet passivated by an organic ligand is governed by monomer diffusivity through the surface ligand monolayer. Therefore, the growth rate in two polar directions can be finely tuned by controlling the strength of ligand–ligand attraction at end surfaces. Building on these findings, we report the synthesis of single-diameter CdSe/CdS core/shell NRs with CdSe cores of controllable position, which reveals a strong structure–optical polarization relationship. The understanding of the NR growth mechanism with controllable anisotropy will serve as a cornerstone for the exquisite design of more complex anisotropic nanostructures.

中文翻译:

胶体双直径和核位置控制的核/壳硫属硫化物纳米棒

为了利用半导体纳米棒(NRs)的形状和结构相关的特性,需要对其生长进行高精度控制和精确设计。硫属硫化镉(CdE; E = S或Se)NRs是这类化合物中研究最多的一类,其生长表现出轴向各向异性,Ë例如,沿着{0001}平面的相反方向的不同增长率。然而,由于难以对生长表面进行即时分析,因此NRs不对称轴向生长的机理尚不清楚。在这里,我们设计了在量子限制条件下的胶体双直径半导体NR(DDNR),它沿长轴具有两个直径不同的部分。DDNRs的细分允许在分子水平上严格评估NR生长的动力学。被有机配体钝化的末端小面的反应性受单体通过表面配体单层的扩散性支配。因此,可以通过控制端面上的配体-配体吸引强度来微调两个极性方向上的生长速率。基于这些发现,我们报告了具有可控位置的CdSe核的单直径CdSe / CdS核/壳NR的合成,揭示了强的结构-光学偏振关系。对具有可控各向异性的NR生长机理的理解将为更复杂的各向异性纳米结构的精巧设计奠定基础。
更新日期:2017-11-19
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