Mechanisms of the shape evolution of CdSe nanocrystals
Mechanisms of the shape evolution of CdSe nanocrystals
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DOI：
10.1021/ja0027766
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发表时间：
2001-02-21
影响因子：
15
通讯作者：
Peng, XG
中科院分区：
文献类型：
--
作者：
Peng, ZA;Peng, XG
对具有有机金属前体的非水溶剂中CDSE量子限制的纳米棒（量子杆）的时间形状演变进行了定量和系统地研究。实验结果揭示了形状演化的三个可区分阶段。在高单体浓度下，纳米晶体仅沿着Wurtzite结构的C轴生长，使该轴成为杆的长轴。在中间浓度下，纳米晶体同时在三个维度上生长。在低单体浓度下，纵横比在纳米晶体表面的颗粒内扩散控制的过程中降低。这个颗粒内成熟阶段;与正常的Ostwald成熟不同，正常的Ostwald成熟，该成熟在较低的单体浓度下，并且是通过单体从小到大的迁移。，添加己基磷酸或四丙基磷酸，强的Cadmium cadmium cadmium codmium cipands，主要是因为它可以使其具有重大的重要性量子杆生长所需的高单体浓度。提出了一个简单的模型，以根据扩散控制来解释面的CDSE纳米晶体的生长。
The temporal shape evolution of CdSe quantum confined nanorods (quantum rods) in nonaqueous solvents with organometallic precursors was studied quantitatively and systematically. The experimental results revealed three distinguishable stages in the shape evolution. At high monomer concentrations, nanocrystals grow exclusively along the c-axis of the wurtzite structure, making this axis the long axis of the rods. At intermediate concentrations, nanocrystals grow simultaneously in three dimensions. At low monomer concentrations, the aspect ratio decreases in a process controlled by intraparticle diffusion on the surface of the nanocrystals. This intraparticle ripening stage;is different from normal Ostwald ripening, which-occurs at lower monomer concentrations and is by monomer migration from small to larger ones., Addition of hexylphosphonic acid or tetradecylphosphonic acid, strong cadmium ligands, is important mainly because it enables the high monomer concentrations needed for the growth of quantum rods. A simple model is proposed to explain the growth of faceted CdSe nanocrystals on the basis of diffusion control.