Stabilization of graphene nanopore
Stabilization of graphene nanopore
复制标题
石墨烯纳米孔的稳定性
DOI：
10.1073/pnas.1400767111
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发表时间：
2014-05-27
影响因子：
11.1
通讯作者：
Chisholm, Matthew F.
中科院分区：
文献类型：
--
作者：
Lee, Jaekwang;Yang, Zhiqing;Chisholm, Matthew F.
意义纳米孔研究的关键驱动力一直是DNA测序的前景，这需要又小又薄的孔才能达到最高的分辨率。通过使用石墨烯，孔通道的长度可以减少到单层原子层。然而，众所周知，石墨烯中的微孔不稳定，不能被碳吸附原子填充。因此，这种孔洞的稳定是实现应用所要解决的关键问题。我们论证了石墨烯中稳定空穴的存在，并从理论上解释了它们为什么是稳定的。我们的发现是朝着开发坚固可靠的基于石墨烯的分子易位设备迈出的重要一步。石墨烯是一种超薄的不透膜。在石墨烯中可控地引入纳米孔将导致涉及水净化、化学分离和DNA测序的应用。然而，石墨烯纳米孔不稳定，不能抵抗碳原子的填充。在这里，使用像差校正的扫描电子显微镜和密度泛函计算，我们报告了硅原子通过桥接空穴周围的悬挂键来稳定石墨烯纳米孔。即使在强烈的电子束照射下，硅钝化的气孔仍保持完好，并在样品制作几个月后观察到它们，表明这些结构本质上是坚固的，对碳填充是稳定的。理论计算揭示了这种稳定效应的潜在机制：硅原子与石墨烯边缘强烈键合，它们对四面体配位的偏好迫使C原子形成伸出石墨烯平面的树枝晶，而不是填充纳米孔。我们的结果为开发稳定的纳米孔提供了一种新的方法，这是迈向可靠的基于石墨烯的分子易位器件的重要一步。
Significance The key driving force for nanopore research has been the prospect of DNA sequencing, which requires small, thin pores for highest resolution. The length of the pore channel can be reduced to a single layer of atoms through the use of graphene. However, it is known that tiny holes in graphene are unstable against filling by carbon adatoms. Thus, the stabilization of such holes is a critical issue to be resolved to enable applications. We demonstrate the existence of stabilized holes in graphene and theoretical understanding of why they are stable. Our discoveries are a major step toward the development of robust and reliable graphene-based molecular translocation devices. Graphene is an ultrathin, impervious membrane. The controlled introduction of nanoscale pores in graphene would lead to applications that involve water purification, chemical separation, and DNA sequencing. However, graphene nanopores are unstable against filling by carbon adatoms. Here, using aberration-corrected scanning transmission electron microscopy and density-functional calculations, we report that Si atoms stabilize graphene nanopores by bridging the dangling bonds around the perimeter of the hole. Si‐passivated pores remain intact even under intense electron beam irradiation, and they were observed several months after the sample fabrication, demonstrating that these structures are intrinsically robust and stable against carbon filling. Theoretical calculations reveal the underlying mechanism for this stabilization effect: Si atoms bond strongly to the graphene edge, and their preference for tetrahedral coordination forces C adatoms to form dendrites sticking out of the graphene plane, instead of filling the nanopore. Our results provide a novel way to develop stable nanopores, which is a major step toward reliable graphene-based molecular translocation devices.