Cao Weiwei, Xu Huakai, Liu Pu, He Yan, Yang Guowei
State Key Laboratory of Optoelectronic Materials and Technologies, Nanotechnology Research Center, School of Materials Science & Engineering, Sun Yat-sen University Guangzhou 510275 Guangdong P. R. China
College of Science, Guangdong University of Petrochemical Technology Maoming 525000 Guangdong P. R. China
Chem Sci. 2022 Dec 6;14(2):338-344. doi: 10.1039/d2sc04926k. eCollection 2023 Jan 4.
Carbyne with one-dimensional sp-hybridized carbon atoms is the third form of carbon following diamond and graphite. Although carbyne nanocrystals have been synthesized, little is known about its structural details. Here, we report experimental evidence of the kinked structure of carbon chains and interchain van der Waals interaction of carbyne nanocrystals by near edge X-ray absorption fine structure (NEXAFS) spectroscopy. We measure the resonance and the feature peaks of the kinked configuration of carbon chains and the van der Waals interaction between chains of carbyne nanocrystals using NEXAFS spectroscopy. We also perform theoretical calculations of density functional theory and simulations based on the super-cell core-hole method for carbon K-edge NEXAFS. The theoretical results are in good agreement with the experimental measurements, which demonstrates that carbyne nanocrystals are van der Waals crystals with kinked chains as structural units. Note that the peak at 288.5 eV in the simulated NEXAFS spectrum implies the possible presence of hydrogen-terminated kinks or hydrogen-terminated chains in carbyne nanocrystals, which clarifies the understanding of the C-H bond in carbyne nanocrystals. These findings are enlightening and significant for pursuing physics and potential applications of carbyne.
具有一维sp杂化碳原子的卡宾是继金刚石和石墨之后的第三种碳形式。尽管已经合成了卡宾纳米晶体，但其结构细节却鲜为人知。在此，我们通过近边X射线吸收精细结构（NEXAFS）光谱报告了卡宾纳米晶体碳链的扭结结构和链间范德华相互作用的实验证据。我们使用NEXAFS光谱测量了卡宾纳米晶体碳链扭结构型的共振峰和特征峰以及链间的范德华相互作用。我们还基于密度泛函理论进行了理论计算，并基于超胞芯孔法对碳K边NEXAFS进行了模拟。理论结果与实验测量结果吻合良好，这表明卡宾纳米晶体是以扭结链为结构单元的范德华晶体。请注意，模拟的NEXAFS光谱中288.5 eV处的峰意味着卡宾纳米晶体中可能存在氢端接的扭结或氢端接的链，这有助于阐明对卡宾纳米晶体中C-H键的理解。这些发现对于探索卡宾的物理性质和潜在应用具有启发性和重要意义。
