Site-selective local fluorination of graphene induced by focused ion beam irradiation.
Site-selective local fluorination of graphene induced by focused ion beam irradiation.
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DOI：
10.1038/srep19719
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发表时间：
2016-01-29
影响因子：
4.6
通讯作者：
Leifer K
中科院分区：
文献类型：
--
作者：
Li H;Daukiya L;Haldar S;Lindblad A;Sanyal B;Eriksson O;Aubel D;Hajjar-Garreau S;Simon L;Leifer K
石墨烯的功能化仍然是这种迷人材料所期望的众多应用的重要挑战。在对石墨烯结构进行修饰或功能化后，要保持其优越的性能，局部方法是一条很有前途的道路。本文报道了一种新技术，可实现石墨烯的精确位点选择性氟化。该方法的基本思想是通过聚焦离子束（FIB）辐照和同时引入XeF2气体来局部自由基化石墨烯。进行了一系列系统的实验，以概述插入缺陷的产生与氟化过程之间的关系。根据随后的x射线光电子能谱（XPS）分析，与正常条件下的氟化相比，观察到同时辐照下石墨烯上的氟浓度增加了6倍。扫描隧道显微镜（STM）显示，氟原子主要定位在缺陷处。实验结果得到密度泛函理论的证实，该理论预测当氟原子与缺陷位点结合时，其结合能会显著增加。所开发的技术允许石墨烯的局部氟化而不使用抗阻剂，并且有可能成为使用多种气体的石墨烯选择性功能化的一般促成因素。
The functionalization of graphene remains an important challenge for numerous applications expected by this fascinating material. To keep advantageous properties of graphene after modification or functionalization of its structure, local approaches are a promising road. A novel technique is reported here that allows precise site-selective fluorination of graphene. The basic idea of this approach consists in the local radicalization of graphene by focused ion beam (FIB) irradiation and simultaneous introduction of XeF2 gas. A systematic series of experiments were carried out to outline the relation between inserted defect creation and the fluorination process. Based on a subsequent X-ray photoelectron spectroscopy (XPS) analysis, a 6-fold increase of the fluorine concentration on graphene under simultaneous irradiation was observed when compared to fluorination under normal conditions. The fluorine atoms are predominately localized at the defects as indicated from scanning tunneling microscopy (STM). The experimental findings are confirmed by density functional theory which predicts a strong increase of the binding energy of fluorine atoms when bound to the defect sites. The developed technique allows for local fluorination of graphene without using resists and has potential to be a general enabler of site-selective functionalization of graphene using a wide range of gases.