Local Structure and Bonding of Carbon Nanothreads Probed by High-Resolution Transmission Electron Microscopy
Local Structure and Bonding of Carbon Nanothreads Probed by High-Resolution Transmission Electron Microscopy
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DOI：
10.1021/jacs.8b13405
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发表时间：
2019-05-01
影响因子：
15
通讯作者：
Alem, Nasim
中科院分区：
文献类型：
--
作者：
Juhl, Stephen J.;Wang, Tao;Alem, Nasim
碳纳米线是以苯为原料，在高压、室温下通过缓慢固相聚合法合成的一种新型一维碳纳米材料。由此产生的螺纹呈现出数百微米的结晶堆积。我们显示了高分辨率电子显微镜（HREM）图像的六角形阵列排列良好的线程列，遍历80-100纳米的厚度制备的样品。电子衍射中的漫散射揭示了纳米线之间填充有轴向和/或方位角错位。退火纳米线衍射中的层线提供了沿其长度沿着平移顺序的第一个证据，表明这种固态反应具有一定的规律性。HREM还揭示了纳米线晶体中的弯曲和缺陷，这些弯曲和缺陷可以导致其衍射斑点的加宽，并且电子能量损失光谱法证实它们主要是spa-杂化的，具有少于27%的sp（2）碳，最有可能与部分饱和的“4度”线相关。
Carbon nanothreads are a new one-dimensional sp(3)-bonded nanomaterial of CH stoichiometry synthesized from benzene at high pressure and room temperature by slow solid-state polymerization. The resulting threads assume crystalline packing hundreds of micrometers across. We show high-resolution electron microscopy (HREM) images of hexagonal arrays of well-aligned thread columns that traverse the 80-100 nm thickness of the prepared sample. Diffuse scattering in electron diffraction reveals that nanothreads are packed with axial and/or azimuthal disregistry between them. Layer lines in diffraction from annealed nanothreads provide the first evidence of translational order along their length, indicating that this solid-state reaction proceeds with some regularity. HREM also reveals bends and defects in nanothread crystals that can contribute to the broadening of their diffraction spots, and electron energy-loss spectroscopy confirms them to be primarily sp a -hybridized, with less than 27% sp(2) carbon, most likely associated with partially saturated "degree-4" threads.