Chlorination of Hydrogenated Silicon Nanosheets Revealed by Solid-State Nuclear Magnetic Resonance Spectroscopy
Chlorination of Hydrogenated Silicon Nanosheets Revealed by Solid-State Nuclear Magnetic Resonance Spectroscopy
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DOI：
10.1021/acs.chemmater.2c02980
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发表时间：
2023-01
影响因子：
8.6
通讯作者：
Rick W. Dorn;Bradley J. Ryan;Sujeewa N S Lamahewage;Mark V. Dodson;J. Essner;R. Biswas;Matthew G. Panthani;Aaron J. Rossini
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文献类型：
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作者：
Rick W. Dorn;Bradley J. Ryan;Sujeewa N S Lamahewage;Mark V. Dodson;J. Essner;R. Biswas;Matthew G. Panthani;Aaron J. Rossini
二维硅纳米片（Si-NS）是由CaSi 2的拓扑脱嵌作用合成的，它是由sp3杂化的硅原子与其他三个骨架硅原子和一个末端原子或官能团（如H、Cl或OH）键合而成的屈曲层组成.在此，我们应用1H {35 Cl}和29 Si {35 Cl}共振-回波饱和-脉冲双共振（RIDDOR）固态NMR实验来直接确认Si-NS中氯化Si原子的存在。绘制1H {35 Cl}双极DOR退相作为35 Cl饱和脉冲偏移的函数显示，35 Cl四极耦合常数（CQ）为38 MHz，与共价键合到硅上的Cl原子一致。模拟1H {35 Cl}的DOR退相曲线表明，Si-Si层间距约为6 μ m。平面波密度泛函理论（DFT）计算表明，随着氯化和羟基化程度的增加，Si-NS的直接带隙跃迁逐渐减小，表明可以通过修饰末端原子或官能团来调节Si-NS的带隙.
Two-dimensional silicon nanosheets (Si-NS) synthesized by topotactic deintercalation of CaSi2are hypothesized to consist of buckled layers of sp3-hybridized silicon atoms that are bonded to three other framework Si atoms and a terminal atom or functional group such as H, Cl, or OH. Here, we apply1H{35Cl} and29Si{35Cl} Resonance-Echo Saturation-Pulse DOuble-Resonance (RESPDOR) solid-state NMR experiments to directly confirm the presence of chlorinated Si atoms within Si-NS. Plotting the1H{35Cl} RESPDOR dephasing as a function of the35Cl saturation pulse offset reveals that the35Cl quadrupolar coupling constant (CQ) is 38 MHz, consistent with Cl atoms that are covalently bonded to silicon. Modeling the1H{35Cl} RESPDOR dephasing curve shows that the Si–Si interlayer spacing is approximately 6 Å. Plane-wave density functional theory (DFT) calculations show that the direct band gap transition of the Si-NS decreases with increasing chlorination and hydroxylation, suggesting that the band gap of Si-NS can be tuned by modifying the terminal atoms or functional groups.