A few-layer covalent network of fullerenes
A few-layer covalent network of fullerenes
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DOI：
10.1038/s41586-022-05401-w
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发表时间：
2023-01-05
期刊：
影响因子：
64.8
通讯作者：
Roy, Xavier
中科院分区：
文献类型：
--
作者：
Meirzadeh, Elena;Evans, Austin M.;Roy, Xavier
碳的两种天然同素异形体，金刚石和石墨，分别是sp(3)杂化和sp(2)杂化原子的扩展网络(1)。通过混合不同的杂化和碳的几何形状，人们可以在概念上构建无数的合成同素异形体。在这里，我们介绍石墨烯，一种C60的二维结晶聚合物，它弥合了分子和延伸碳材料之间的鸿沟。其组成富勒烯亚基六边形排列在共价相互连接的分子片上。我们报道了电荷中性的纯碳基宏观晶体，其大到足以机械剥离以产生具有干净界面的分子薄片-这是创建异质结构和光电子器件的关键要求2。该合成方法需要通过化学蒸汽传输生长层状聚合物（Mg4C60）(8)的单晶，随后用稀酸除去镁。我们探索了这种材料的导热性，发现它比分子C-60的导热性要高得多，这是面内共价键的结果。此外，利用透射电子显微镜和近场纳米光致发光光谱对少层石墨烯薄片进行成像，发现了云纹状超晶格的存在(3)。更广泛地说，通过分子前体聚合合成扩展碳结构为系统设计具有可调谐光电性能的二维异质结构材料指明了一条清晰的道路。
The two natural allotropes of carbon, diamond and graphite, are extended networks of sp(3)-hybridized and sp(2)-hybridized atoms, respectively(1). By mixing different hybridizations and geometries of carbon, one could conceptually construct countless synthetic allotropes. Here we introduce graphullerene, a two-dimensional crystalline polymer of C60 that bridges the gulf between molecular and extended carbon materials. Its constituent fullerene subunits arrange hexagonally in a covalently interconnected molecular sheet. We report charge-neutral, purely carbon-based macroscopic crystals that are large enough to be mechanically exfoliated to produce molecularly thin flakes with clean interfaces-a critical requirement for the creation of heterostructures and optoelectronic devices2. The synthesis entails growing single crystals of layered polymeric (Mg4C60)(8) by chemical vapour transport and subsequently removing the magnesium with dilute acid. We explore the thermal conductivity of this material and find it to be much higher than that of molecular C-60, which is a consequence of the in-plane covalent bonding. Furthermore, imaging few-layer graphullerene flakes using transmission electron microscopy and near field nano-photoluminescence spectroscopy reveals the existence of moire-like superlattices(3). More broadly, the synthesis of extended carbon structures by polymerization of molecular precursors charts a clear path to the systematic design of materials for the construction of two-dimensional heterostructures with tunable optoelectronic properties.