Molecular tunneling in large tubes of 3D nitrogenated micropore materials
Molecular tunneling in large tubes of 3D nitrogenated micropore materials
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DOI：
10.1063/1.5045194
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发表时间：
2018-11
影响因子：
3.2
通讯作者：
A. Pimachev;Y. Dahnovsky
中科院分区：
文献类型：
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作者：
A. Pimachev;Y. Dahnovsky
我们研究新型 3D 材料，即 π 共轭微孔聚合物 (aza-CMP)，其中 2D 层通过甲酸和乙酸基团连接。计算了晶体参数和能带结构。具有乙酸 (Eg3D=1.04eV) 和甲酸 (Eg3D=1.26eV) 酸连接基团的 3D 晶体的能隙小于 2D 材料 (Eg2D=1.64eV) 的能隙。通过改变选择规则和光谱，3D 晶体的对称性变得低于 2D aza-CMP。对于具有乙酸的 aza-CMP，上部空穴带变得非简并，而对于具有甲酸连接基团的 aza-CMP，上部空穴带变得双重简并。价带中的上能带变得更加平坦，这意味着空穴质量较重，从而导致空穴迁移率较低。我们还研究了通过通道的分子运输。我们发现CH 4 分子在大孔材料中很容易沿着管移动，而在小孔（带有乙酸连接基团）晶体中受到阻碍。氨分子以很大的活化能（约0.39eV）附着在管壁上。对于大分子NR 4 (R=CH 3, C 2H 5)，化学反应在窄管中发生。特别地，N(CH 3) 4 分子在碎片中衰变。两个原子N和C附着在管壁上，三个分子片段CH 4 、C 2H 6 和H 2 可以进一步沿着通道形成隧道。 π-共轭微孔聚合物结构的低能隙和可调传输特性可用于电子、能量收集、气体分离、选择性气体传输、储氢和生物医学（药物输送）。我们研究新型3D材料，π-共轭微孔聚合物（aza-CMP），其中2D层通过甲酸和乙酸基团连接。计算了晶体参数和能带结构。具有乙酸 (Eg3D=1.04eV) 和甲酸 (Eg3D=1.26eV) 酸连接基团的 3D 晶体的能隙小于 2D 材料 (Eg2D=1.64eV) 的能隙。通过改变选择规则和光谱，3D 晶体的对称性变得低于 2D aza-CMP。对于具有乙酸的 aza-CMP，上部空穴带变得非简并，而对于具有甲酸连接基团的 aza-CMP，上部空穴带变得双重简并。价带中的上能带变得更加平坦，这意味着空穴质量较重，从而导致空穴迁移率较低。我们还研究了通过通道的分子运输。我们发现CH 4 分子在大孔材料中很容易沿着管移动，而在小孔（带有乙酸连接基团）晶体中受到阻碍。氨分子位于...
We study new 3D materials, π-conjugated microporous polymers (aza-CMPs), where 2D layers are connected by methanoic and ethanoic acid groups. The crystal parameters and the band structures are calculated. The energy gaps for a 3D crystal with the ethanoic ( Eg3D=1.04eV) and methanoic ( Eg3D=1.26eV) acid connecting groups are smaller than those for a 2D material ( Eg2D=1.64eV). The symmetry of a 3D crystal becomes lower than for a 2D aza-CMP by changing selection rules and optical spectra. The upper hole bands become non-degenerate for an aza-CMP with ethanoic acid and are doubly degenerate for an aza-CMP with methanoic acid connecting groups. The upper bands in the valence zone become more flat implying heavier hole masses that lead to lower hole mobilities. We also investigate molecular transport through the channels. We find that a CH 4 molecule moves easily along the tube in a large pore material and is hindered in a small pore (with ethanoic acid connecting groups) crystal. The ammonia molecule is attached to the tube walls with a large activation energy (about 0.39eV). For the large molecules NR 4 (R=CH 3, C 2H 5), chemical reactions take place in the narrow tubes. In particular, an N(CH 3)4 molecule decays in the fragments. The two atoms, N and C, are attached to the tube walls, and the three molecular fragments, CH 4, C 2H 6, and H 2, can further tunnel along the channels. The low energy gaps and tunable transport properties of π-conjugated microporous polymeric structures can be used for electronics, energy harvesting, gas separation, selective gas transport, hydrogen storage, and biomedicine (drug delivery).We study new 3D materials, π-conjugated microporous polymers (aza-CMPs), where 2D layers are connected by methanoic and ethanoic acid groups. The crystal parameters and the band structures are calculated. The energy gaps for a 3D crystal with the ethanoic ( Eg3D=1.04eV) and methanoic ( Eg3D=1.26eV) acid connecting groups are smaller than those for a 2D material ( Eg2D=1.64eV). The symmetry of a 3D crystal becomes lower than for a 2D aza-CMP by changing selection rules and optical spectra. The upper hole bands become non-degenerate for an aza-CMP with ethanoic acid and are doubly degenerate for an aza-CMP with methanoic acid connecting groups. The upper bands in the valence zone become more flat implying heavier hole masses that lead to lower hole mobilities. We also investigate molecular transport through the channels. We find that a CH 4 molecule moves easily along the tube in a large pore material and is hindered in a small pore (with ethanoic acid connecting groups) crystal. The ammonia molecule is at...