State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, China.
Synergetic Extreme Condition User Facility, Jilin University, Changchun, China.
Nature. 2021 Nov;599(7886):599-604. doi: 10.1038/s41586-021-03882-9. Epub 2021 Nov 24.
Amorphous materials inherit short- and medium-range order from the corresponding crystal and thus preserve some of its properties while still exhibiting novel properties. Due to its important applications in technology, amorphous carbon with sp or mixed sp-sp hybridization has been explored and prepared, but synthesis of bulk amorphous carbon with sp concentration close to 100% remains a challenge. Such materials inherit the short-/medium-range order of diamond and should also inherit its superior properties. Here, we successfully synthesized millimetre-sized samples-with volumes 10-10 times as large as produced in earlier studies-of transparent, nearly pure sp amorphous carbon by heating fullerenes at pressures close to the cage collapse boundary. The material synthesized consists of many randomly oriented clusters with diamond-like short-/medium-range order and possesses the highest hardness (101.9 ± 2.3 GPa), elastic modulus (1,182 ± 40 GPa) and thermal conductivity (26.0 ± 1.3 W m K) observed in any known amorphous material. It also exhibits optical bandgaps tunable from 1.85 eV to 2.79 eV. These discoveries contribute to our knowledge about advanced amorphous materials and the synthesis of bulk amorphous materials by high-pressure and high-temperature techniques and may enable new applications for amorphous solids.
非晶态材料从相应的晶体中继承了短程和中程有序，因此保留了其某些性质，同时又表现出了一些新的性质。由于其在技术中的重要应用，人们已经探索并制备了具有 sp 或混合 sp-sp 杂化的非晶态碳，但合成 sp 浓度接近 100%的块状非晶态碳仍然是一个挑战。这些材料继承了金刚石的短程/中程有序，也应该继承其优异的性能。在这里，我们通过在接近笼塌边界的压力下加热富勒烯，成功地合成了毫米级大小的、比以前研究中合成的大 10-10 倍的透明、近纯 sp 非晶态碳样品。所合成的材料由许多具有类金刚石短程/中程有序的随机取向的团簇组成，具有最高的硬度（101.9±2.3GPa）、弹性模量（1182±40GPa）和热导率（26.0±1.3WmK），这些都是在任何已知的非晶材料中观察到的。它还表现出从 1.85eV 到 2.79eV 可调的光学带隙。这些发现有助于我们了解先进的非晶态材料以及通过高压高温技术合成块状非晶态材料的知识，可能为非晶态固体开辟新的应用前景。
