西北农林魏宁副教授课题组：高效黑磷烯手征筛选方法 | Nanoscale 论文推荐

责任编辑 谭坤

二维材料普遍具有各向异性的特征，比如不同手性具有不同的电学，力学和热学性能。一直以来，如何高效分离不同手性的二维材料，用以制备发挥其优势性能的纳米器件，被认为是二维材料研究中重要的问题之一。

近日，西北农林科技大学、西悉尼大学、中国科学院上海应用物理研究所与瑞士苏黎世联邦理工学院（ETH）的研究者合作发现，利用黑磷烯在之字形（Zigzag）和扶手椅形（Armchair）两个手性方向的不同的弯曲刚度（Bending Stiffness），可以高效地分离这两种不同手征的黑磷烯。

黑磷烯的弯曲形变需要克服弯曲能，而其在 Zigzag 方向的弯曲刚度约为 Armchair 方向的4倍。因此，这一力学的各向异性使得黑磷烯在 Armchair 方向比 Zigzag 方向更容易发生折叠，弯曲与卷曲。研究者根据这一特性，提出了3种理论模型来实现高效的手性筛选分离，分别是：（1）纳米颗粒诱导黑磷烯自包裹；（2）悬空桥模型；（3）纳米滚轴模型，如下图所示：

图1. 纳米液滴诱导黑磷烯自包裹，只有armchair方向发生了自折叠包裹， zigzag 方向的黑磷烯保持展开状态。

图2. 悬空桥模式黑磷烯手续筛选模型，随着活塞下滑，只有armchair手性的黑磷烯随着活塞向下移动并脱离了表面。

图3.通过纳米管滚轴卷曲筛选 Armchair 手征黑磷烯，留下 Zigzag 手征黑磷烯

该项研究得到国家自然科学基金委、瑞士联邦政府基金、中国科学院等单位的共同支持。相关研究成果发表在纳米尺度上（Nanoscale, 2018,），并引起海内外实验组的关注。

相关论文信息

标题 Efficient Selection Methods for Black Phosphorene Nanoribbons 

期刊 Nanoscale

作者 Ning Wei,  Yang Chen,  Yingyan Zhang,  Zhou Chui,  Xiaoli Hao,  Ke Xu,  Kun Cai  and  Jige Chen 

DOI:10.1039/C7NR08311D.

摘要 Black phosphorene (BP) has shown anisotropic electronic, mechanical, and thermal properties for various promising applications in recent years. To take full advantage of this unique anisotropy in its further functional design and application, it is paramount to separate BP with well-defined chirality quickly and precisely. In this paper, we propose three efficient methods to separate BP ribbons with different chirality by utilizing their strong chirality-dependent bending stiffness. Our results show that the bending stiffness in the zigzag direction is more than 4 times larger than that in the armchair direction. The mechanical anisotropy and bending-binding competition are used to realize chirality-dependent design. To fold, wrap or scroll the BP nanoribbons, it is necessary to overcome the bending stiffness by adding the binding energy between the BP nanoribbons and the contact surfaces. Due to the mechanical anisotropy, the BP nanoribbons could easily be folded, wrapped and scrolled along the armchair direction rather than the zigzag direction. Therefore, we introduce this characteristic in our chirality separation designs as, the self-folding model to fold up the armchair BP nanoribbons by nanoparticle, the suspension-bridge sieve model to pull down the armchair BP nanoribbons, and the nanorod-roller model to scroll up the armchair nanoribbons. Our separation methods in this research can be extended to other 2D materials with anisotropic mechanical properties. We hope our findings would offer a novel route for manufacturing of BP-based electronic devices and self-assembly nano-devices.

链接 http://pubs.rsc.org/en/content/articlelanding/2018/nr/c7nr08311d#!divAbstract

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