Shape control of CdSe nanocrystals
Shape control of CdSe nanocrystals
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DOI：
10.1038/35003535
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发表时间：
2000-03-02
期刊：
影响因子：
64.8
通讯作者：
Alivisatos, AP
中科院分区：
文献类型：
--
作者：
Peng, XG;Manna, L;Alivisatos, AP
纳米大小的无机点，试管和电线表现出广泛的电气和光学特性（1,2），它们敏感地依赖于尺寸和形状（3,4），并且具有基本和技术兴趣。与零维系统的合成相反，一维系统的现有制备通常会产生很难分离的管子或杆网络（5-12）。而且，在光学活跃的II-YI和III-V半导体的情况下，所得的杆直径太大而无法表现出量子约束效应（6,8-10）。因此，除了某些金属纳米晶（13）之外，没有制备方法可以产生可溶和单分散粒子的量子，它们在其两个尺寸中被量子限制。对于半导体，基准制备是通过将前体分子注入热表面活性剂中的几乎球形II-VI和III-V纳米晶体的生长（14,15）。在这里，我们证明了对II-VI半导体镉硒化的生长动力学的控制可用于改变所得颗粒的形状从几乎球形的形态到类似杆状的形态，其长宽比高达十到一个。该方法不仅适用于测试量子限制理论，而且对于获得具有光谱特性的颗粒，这些特性在生物标记实验中可能有优势（16,17）和发光二极管（18,19）中具有优势。
Nanometre-size inorganic dots, tubes and wires exhibit a wide range of electrical and optical properties(1,2) that depend sensitively on both size and shape(3,4), and are of both fundamental and technological interest. In contrast to the syntheses of zero-dimensional systems, existing preparations of one-dimensional systems often yield networks of tubes or rods which are difficult to separate(5-12). And, in the case of optically active II-YI and III-V semiconductors, the resulting rod diameters are too large to exhibit quantum confinement effects(6,8-10). Thus, except for some metal nanocrystals(13), there are no methods of preparation that yield soluble and monodisperse particles that are quantum-confined in two of their dimensions. For semiconductors, a benchmark preparation is the growth of nearly spherical II-VI and III-V nanocrystals by injection of precursor molecules into a hot surfactant(14,15). Here we demonstrate that control of the growth kinetics of the II-VI semiconductor cadmium selenide can be used to vary the shapes of the resulting particles from a nearly spherical morphology to a rod-like one, with aspect ratios as large as ten to one. This method should be useful, not only for testing theories of quantum confinement, but also for obtaining particles with spectroscopic properties that could prove advantageous in biological labelling experiments(16,17) and as chromophores in light-emitting diodes(18,19).