High-Yield Synthesis of Ultrathin Metal Nanowires in Carbon Nanotubes
High-Yield Synthesis of Ultrathin Metal Nanowires in Carbon Nanotubes
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DOI：
10.1002/anie.200902615
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发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Shinohara, H.
中科院分区：
文献类型：
--
作者：
Kitaura, R.;Nakanishi, R.;Shinohara, H.
由于量子效应，限制在低维纳米结构中的电子表现出各种新的物理性质，这可能导致纳米电子器件的应用为了提高这些性能，纳米结构需要非常小并且具有高宽高比，因此，原子薄纳米线的合成是材料科学中最有趣的话题之一。然而，由于其固有的结构不稳定性和较高的化学反应活性，这种超薄纳米线总是不稳定的。因此，除了高产率可控的纳米线合成外，其伴随的结构稳定性至关重要。为此，我们重点研究了利用碳纳米管（CNTs）的伪一维纳米空间进行直接纳米填充反应。直径在0.4 ~ 50 nm之间的碳纳米管伪一维空心纳米空间具有化学稳定性和机械稳定性，可作为各种纳米结构自组装的理想纳米空间。事实上，在过去的几十年里，关于碳纳米管中纳米团簇和纳米线形成的一些研究已经被报道然而，在碳纳米管内部形成高产量的原子级细纳米线一直是困难的。我们已经开发了一种简单而有效的合成方法，即在单壁碳纳米管（SWCNTs）和双壁碳纳米管（DWCNTs）中以高填充率（通常为bbb80 %）合成典型的1-4个原子链的超薄纳米线。这些纳米线被CNTs的周围壁完全保护，因此在空气环境下，甚至在溶液中超声处理后，都不会氧化和结构分解。这一结果与先前报道的金属纳米线，特别是所谓的单原子纳米线形成了鲜明的对比，后者即使在超高真空条件下也只能存活很短的时间此外，本方法制备的超薄金属纳米线在碳纳米管可以
Electrons confined in low-dimensional nanostructures show various novel physical properties owing to quantum effects that could lead to applications in nanoelectronic devices.[1] To enhance such properties, the nanostructures need to be very small and have high aspect ratios, and, thus, the synthesis of atomically thin nanowires is one of the most intriguing topics in materials science. However, such an ultrathin nanowire is always not stable because of the intrinsic structural instability and high chemical reactivity. Therefore, in addition to the high-yield controlled synthesis of such nanowires, its concomitant structural stabilization is of key importance. For this purpose, we have focused on a direct nanofilling reaction using the pseudo-one-dimensional nanospace of carbon nanotubes (CNTs).The chemically and mechanically stable pseudo-1D hollow nanospace of CNTs ranging in size from 0.4 to 50 nm across can act as an ideal nanosized space for the selfassembly of various nanostructures. In fact, several studies on the formation of nanoclusters and nanowires in CNTs have been reported over the past couple of decades.[2] However, the formation of atomically thin nanowires inside CNTs in high yield has been difficult to date. We have developed a simple and effective synthetic procedure, whereby ultrathin nanowires of typically 1–4 atomic chains are synthesized with a high filling fraction (typically> 80%) in both single-wall CNTs (SWCNTs) and double-wall CNTs (DWCNTs). These nanowires are completely protected by surrounding walls of CNTs and are therefore free from oxidation as well as from structural decomposition under ambient air environments and even after ultrasonication in solution. This result is in marked contrast to previously reported metal nanowires, especially to the so-called single atomic nanowires, which can survive for only a very short period of time even under ultrahigh vacuum conditions.[3] Furthermore, the present method to prepare ultrathin metal nanowires in CNTs can