Chinese scientists discover new carbon family single crystal materials
2022-06-20
(Figure A: schematic diagram of single crystal structure of quasi hexagonal polymeric C60. Each C60 is connected to the surrounding six C60 through C-C covalent bonds. Figure B: scanning transmission electron microscope picture of single-layer polymeric C60. The C60 cage cluster is shown as a ring in the figure.) The reporter learned from the Chinese Academy of Sciences that the team of Zhengjian, a researcher from the Institute of chemistry, Chinese Academy of Sciences, has created a new type of carbon allotrope single crystal - monolayer polymerized C60 under normal pressure through simple reaction conditions. This new carbon material has high crystallinity, good thermodynamic stability and moderate band gap, which provides a new idea for the study of carbon materials. The work results were published in the international academic journal Nature on June 16. Carbon materials have always been regarded as a kind of future materials. Some material scientists even believe that human society has entered the future "carbon based electronic age" from the current "silicon-based electronic age". By adjusting the band gap of carbon materials, they can show very different electrical properties, such as metals, semiconductors and insulators, which are widely used in the fields of transistors, energy storage devices, superconductors and so on. The properties of carbon materials are closely related to their topological structures. Therefore, it is of great significance to study new two-dimensional carbon allotropes, especially new structures with band gaps, and establish the relationship between structure and physical properties. The preparation of new carbon materials has always been a cutting-edge scientific issue in the field of materials. Each discovery of new carbon materials represented by fullerenes, carbon nanotubes, graphene and graphene has triggered a research upsurge among materials scientists. Substances composed of the same element exhibit different physical and chemical properties due to different atomic arrangements. We call them allotropes. Carbon has many allotropes, including diamond, graphite, fullerene, carbon nanotube, graphene and graphene. Up to now, the smallest unit to construct two-dimensional materials is a single atom. As the basic unit, nano clusters called artificial atoms have not been able to construct a more advanced two-dimensional topology. Because the yield of carbon carbon bonding reaction is not 100% and the reaction is irreversible, it is almost impossible to prepare two-dimensional cluster carbon single crystals by using the traditional chemical reaction from bottom to top through the molecular "brick" method. In recent years, Zheng Jian's research group has devoted itself to the research. After 5 years, the single-layer two-dimensional polymerized C60 single crystal has been successfully prepared by using the doping polymerization stripping two-step method, and the exact valence bond structure has been obtained. Due to the asymmetric bonding structure, each C60 unit in the monolayer polymeric C60 is stretched into an ellipsoid with the same direction, which makes this new carbon material have significant Planar Anisotropy, such as anisotropic phonon mode and conductivity, indicating that this material has great application prospects in nonlinear optics and functional electronic devices. In addition, due to its unique conjugated carbon structure, huge superlattice and porous skeleton structure, this two-dimensional clustered carbon material also has potential applications in the fields of superconductivity, quantum computing, spin transport, information and energy storage, catalysis and so on. (Xinhua News Agency)
Edit:Li Jialang Responsible editor:Mu Mu
Source:people.com
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