The European Physical Journal B ( IF 1.6 ) Pub Date : 2021-08-03 , DOI: 10.1140/epjb/s10051-021-00169-w Z. Yang 1 , J. Y. Song 1 , J. T. Guo 1 , X. W. Zhao 1 , G. C. Hu 1 , X. B. Yuan 1 , J. F. Ren 1, 2
|
Abstract
Two-dimensional (2D) van der Waals heterostructures (vdWHs) show great potential applications in the field of electronic and optoelectronic devices. In this work, first-principles calculations under hybrid HSE06 functional are performed to explore the electronic and optical properties of \(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH. Our results show that the \(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH owns a direct band gap of 2.73 eV, which is smaller than that of GeC monolayer. Meanwhile, this vdWH shows improved ability to absorb visible light and high-energy photons compared with the \(\hbox {Ca(OH)}_{2}\) and the GeC monolayers. The valence band maximum (VBM) potential of \(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) is lower than that of GeC, which means that the \(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH has better oxidation than that of the GeC monolayer. On the other hand, the \(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH also satisfies the requirement for photocatalytic overall water splitting. These findings indicate that \(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH is a promising candidate for optoelectronic devices and photocatalysis.
Graphic abstract
The electronic structure and photocatalytic properties of Ca(OH)2/GeC van der Waals heterostructure (vdWH) have been investigated through first principles calculation based on density functional theory. The calculation results show that among GeC monolayer, Ca(OH)\(_{2}\) monolayer and Ca(OH)\(_2\)/GeC vdWH, the Ca(OH)\(_2\)/GeC vdWH has the smallest band gap. The charge is transferred from the Ca(OH)\(_2\) layer to the GeC layer when the vdWH is synthesized. The vdWH improves the absorption in the visible light range (\(1.6~\mathrm{eV}< \mathrm{E} < 3.1~\mathrm{eV}\)) compared with that of the GeC monolayer. The VBM potential of Ca(OH)\(_2\)/GeC is higher than that of the GeC monolayer, so the oxidation ability of holes of Ca(OH)\(_2\)/GeC vdWH is stronger than that of the GeC monolayer. On the other hand, the Ca(OH)\(_2\)/GeC vdWH also satisfies the requirements for photocatalytic overall water splitting. These characteristics of the Ca(OH)\(_2\)/GeC vdWH show great application potential in the field of optoelectronic devices and photocatalysis.
中文翻译：
$$\hbox {Ca(OH)}_{2}$$ Ca(OH) 2 /GeC van der Waals 异质结构中的电子结构和增强的光催化性能
摘要
二维 (2D) 范德华异质结构 (vdWHs) 在电子和光电器件领域显示出巨大的潜在应用。在这项工作中，在混合 HSE06 泛函下进行第一性原理计算以探索\(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH的电子和光学性质。我们的结果表明，\(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH 的直接带隙为 2.73 eV，小于 GeC 单层的带隙。同时，与\(\hbox {Ca(OH)}_{2}\)和 GeC 单层相比，该 vdWH 显示出更好的吸收可见光和高能光子的能力。\(\hbox {Ca(OH)}_{2}/\hbox {GeC}\)的价带最大值 (VBM) 势低于 GeC，这意味着\(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH 比 GeC 单层具有更好的氧化性。另一方面，\(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH 也满足光催化整体水分解的要求。这些发现表明\(\hbox {Ca(OH)}_{2}/\hbox {GeC}\) vdWH 是光电器件和光催化的有希望的候选者。
图形摘要
已经通过基于密度泛函理论的第一性原理计算研究了 Ca(OH)2/GeC 范德华异质结构 (vdWH) 的电子结构和光催化性能。计算结果表明，在GeC单层中，Ca(OH) \(_{2}\)单层和Ca(OH) \(_2\) /GeCvdWH中，Ca(OH) \(_2\) /GeCvdWH有最小带隙。当合成 vdWH 时，电荷从 Ca(OH) \(_2\)层转移到 GeC 层。与 GeC 单层相比，vdWH 改善了可见光范围内的吸收（\(1.6~\mathrm{eV}< \mathrm{E} < 3.1~\mathrm{eV}\)）。Ca(OH) \(_2\)的 VBM 势/GeC 高于 GeC 单层，因此 Ca(OH) \(_2\) /GeC vdWH空穴的氧化能力强于 GeC 单层。另一方面，Ca(OH) \(_2\) /GeC vdWH 也满足光催化全分解水的要求。Ca(OH) \(_2\) /GeC vdWH 的这些特性在光电器件和光催化领域显示出巨大的应用潜力。
京公网安备 11010802027423号