Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp2 and sp3). Exploring new forms of carbon has been the eternal theme of scientific research. Herein, we report on amorphous (AM) carbon materials with a high fraction of sp3 bonding recovered from compression of fullerene C60 under high pressure and high temperature, previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5–2.2 eV, comparable to that of widely used AM silicon. Comprehensive mechanical tests demonstrate that synthesized AM-III carbon is the hardest and strongest AM material known to date, and can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.

中文翻译：

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发现碳基最强和最硬的无定形材料

碳是最引人入胜的元素之一，因为其结构多样的同素异形体形式源于其键合品种（sp、sp2 和 sp3）。探索碳的新形态一直是科学研究的永恒主题。在此，我们报告了在高压和高温下从富勒烯 C60 的压缩中回收的具有高比例 sp3 键合的无定形 (AM) 碳材料，这是以前未探索过的。对光致发光和吸收光谱的分析表明，它们是半导体，带隙范围为 1.5-2.2 eV，与广泛使用的 AM 硅相当。综合力学测试表明，合成的 AM-III 碳是迄今为止已知的最硬和最强的 AM 材料，可以划伤金刚石晶体并接近其强度。