Chemically Modulating the Twist Rate of Helical van der Waals Crystals,Chemistry of Materials

当前位置： X-MOL 学术 › Chem. Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Chemically Modulating the Twist Rate of Helical van der Waals Crystals
Chemistry of Materials ( IF 7.2 ) Pub Date : 2020-01-02 , DOI: 10.1021/acs.chemmater.9b03779
Zixuan Fang _{1,

2} , Yin Liu _{1,

3} , Stephen Gee ₁ , Shuren Lin _{1,

3} , Sean Koyama ₁ , Chi So ₁ , Fuchuan Luo _{1,

2} , Rui Chen ₁ , Bin Tang ₂ , Jie Yao _{1,

3}

Affiliation

Twisted van der Waals (vdW) materials with a controllable twist are of great interest because the twist offers new opportunities to modify the optoelectronic properties of the materials, giving rise to exotic phenomena, such as superconductivity, moiré excitons, and chiroptical response. Recently, we have synthesized helical vdW crystals with a periodic twist via the vapor–liquid–solid (VLS) growth of dislocated germanium sulfide nanowires with an Eshelby twist. The twist rates and periods of these structures are determined by the radii of the dislocated nanowires, which are defined by the size of the droplets catalyzing the VLS process. In this work, we tailor the twist rates and periods of the structures via chemically modulating the droplet size and the diameter of dislocated vdW nanowires. Our chemical analysis reveals that the growth of twisted GeS nanowires is catalyzed by droplets of an Au–Ge alloy. The size of the catalyst droplets was tailored by introducing GeSe into the growth. The addition of GeSe significantly increases the surface energy of the droplets, increasing the size of the droplets. This results in the growth of GeS_1–xSe_x with decreased twist rates. The chemical modulation of the droplet size is correlated with the change of germanium concentration (supersaturation) in the alloy droplets, consistent with the Gibbs–Thomson effect. Increasing the selenium concentration in the GeS_1–xSe_x from x = 0 to x = 0.11 decreases the twist rate from 0.59 to 0.22 rad/μm, increasing the period from 8 to 15 μm. The chemical modulation demonstrates good potential to tailor the twist rate and period of helical vdW crystals, providing more flexibility to modulate the optoelectronic properties and chiral light–matter interactions. Moreover, adding GeS into the source powder provides a means to tune the composition of the nanowires and mesoscale twisted crystals as GeS_1-xSe_x alloy structures are produced. Our Raman spectroscopy and photoluminescence spectroscopy studies suggest that the compositional engineering in GeS_1–xSe_x has good potential to tune the optoelectronic property.

中文翻译：

化学调节螺旋范德华晶体的扭曲速率

具有可控扭曲度的扭曲范德华（vdW）材料引起人们极大的兴趣，因为这种扭曲为改变材料的光电性能提供了新的机会，从而引起了诸如超导电性，莫尔激子和手性响应等奇特现象。最近，我们通过具有Eshelby扭曲的位错的硫化锗纳米线的汽-液-固（VLS）生长合成了具有周期性扭曲的螺旋vdW晶体。这些结构的扭曲速率和周期由位错的纳米线的半径决定，半径由催化VLS过程的液滴大小确定。在这项工作中，我们通过化学调节液滴尺寸和位错vdW纳米线的直径来调整结构的扭曲速率和周期。我们的化学分析表明，扭曲的GeS纳米线的生长受到Au-Ge合金液滴的催化。通过将GeSe引入生长中来调整催化剂液滴的大小。GeSe的添加显着增加了液滴的表面能，从而增加了液滴的尺寸。这导致GeS的增长_{1– x} Se _x扭曲率降低。液滴尺寸的化学调制与合金液滴中锗浓度的变化（过饱和）相关，这与吉布斯-汤姆森效应一致。将GeS _{1– x} Se _x中的硒浓度从x = 0增加到x= 0.11将扭曲率从0.59降低到0.22 rad /μm，周期从8增大到15μm。化学调制显示出调整螺旋vdW晶体的扭曲速率和周期的良好潜力，为调制光电特性和手性光-质相互作用提供了更大的灵活性。此外，在原料粉末中添加GeS提供了一种在制备GeS _1-x Se _x合金结构时调节纳米线和中尺度扭曲晶体组成的方法。我们的拉曼光谱和光致发光光谱研究表明，GeS _{1– x} Se _x中的成分工程具有很好的潜力来调节光电性能。

更新日期：2020-01-04

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11