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Self‐Organization of Amorphous Carbon Nanocapsules into Diamond Nanocrystals Driven by Self‐Nanoscopic Excessive Pressure under Moderate Electron Irradiation without External Heating
Small ( IF 13.0 ) Pub Date : 2017-11-13 , DOI: 10.1002/smll.201702072 Chengbing Wang 1 , San Ling 1 , Jin Yang 2 , Dewei Rao 2 , Zhiguang Guo 3
Small ( IF 13.0 ) Pub Date : 2017-11-13 , DOI: 10.1002/smll.201702072 Chengbing Wang 1 , San Ling 1 , Jin Yang 2 , Dewei Rao 2 , Zhiguang Guo 3
Affiliation
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Phase transformation between carbon allotropes usually requires high pressures and high temperatures. Thus, the development of low‐temperature phase transition approaches between carbon allotropes is highly desired. Herein, novel amorphous carbon nanocapsules are successfully synthesized by pulsed plasma glow discharge. These nanocapsules are comprised of highly strained carbon clusters encapsulated in a fullerene‐like carbon matrix, with the formers serving as nucleation sites. These nucleation sites favored the formation of a diamond unit cell driven by the self‐nanoscopic local excessive pressure, thereby significantly decreasing the temperature required for its transformation into a diamond nanocrystal. Under moderate electron beam irradiation (10–20 A cm−2) without external heating, self‐organization of the energetic carbon clusters into diamond nanocrystals is achieved, whereas the surrounding fullerene‐like carbon matrix remains nearly unchanged. Molecular dynamics simulations demonstrate that the defective rings as the active sites dominate the phase transition of amorphous carbon to diamond nanocrystal. The findings may open a promising route to realize phase transformation between carbon allotropes at a lower temperature.
中文翻译：
在没有外部加热的情况下，在中等电子辐照下，自纳米超压驱动非晶态碳纳米囊自组织成金刚石纳米晶体
碳同素异形体之间的相变通常需要高压和高温。因此，迫切需要开发碳同素异形体之间的低温相变方法。本文中，通过脉冲等离子体辉光放电成功地合成了新型无定形碳纳米胶囊。这些纳米胶囊由封装在富勒烯状碳基质中的高应变碳簇组成，前者充当成核位点。这些成核位点有利于形成由自纳镜局部过大压力驱动的金刚石晶胞，从而显着降低了其转变为金刚石纳米晶体所需的温度。在中等电子束辐照下（10–20 A cm -2）无需外部加热，就可以将高能碳簇自组织成金刚石纳米晶体，而周围的富勒烯样碳基质几乎保持不变。分子动力学模拟表明，作为活性位点的缺陷环支配着无定形碳到金刚石纳米晶体的相变。这些发现可能为在较低温度下实现碳同素异形体之间的相变开辟一条有希望的途径。
更新日期：2017-11-13
中文翻译：
在没有外部加热的情况下，在中等电子辐照下，自纳米超压驱动非晶态碳纳米囊自组织成金刚石纳米晶体
碳同素异形体之间的相变通常需要高压和高温。因此，迫切需要开发碳同素异形体之间的低温相变方法。本文中，通过脉冲等离子体辉光放电成功地合成了新型无定形碳纳米胶囊。这些纳米胶囊由封装在富勒烯状碳基质中的高应变碳簇组成，前者充当成核位点。这些成核位点有利于形成由自纳镜局部过大压力驱动的金刚石晶胞，从而显着降低了其转变为金刚石纳米晶体所需的温度。在中等电子束辐照下（10–20 A cm -2）无需外部加热，就可以将高能碳簇自组织成金刚石纳米晶体，而周围的富勒烯样碳基质几乎保持不变。分子动力学模拟表明，作为活性位点的缺陷环支配着无定形碳到金刚石纳米晶体的相变。这些发现可能为在较低温度下实现碳同素异形体之间的相变开辟一条有希望的途径。
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