Brill Adam R, Kuntumalla Mohan Kumar, de Ruiter Graham, Koren Elad
Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 3200008, Israel.
Faculty of Materials Science and Engineering, Israel Institute of Technology, Technion City, Haifa 3200008, Israel.
ACS Appl Mater Interfaces. 2020 Jul 29;12(30):33941-33949. doi: 10.1021/acsami.0c09722. Epub 2020 Jul 14.
Functionalized two-dimensional materials (2DMs) are attracting much attention due to their promising applications in nanoscale devices. Producing continuous and homogeneous surface assemblies with a high degree of order has been challenging. In this work, we demonstrate that by noncovalently self-assembling molecular platforms on 2DMs, high-quality and highly ordered monolayers can be generated. The high degree of order and uniformity of the self-assembled monolayer layers were confirmed by a variety of analytic techniques including time-of-flight secondary ion mass spectrometry, scanning tunnelling microscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. Furthermore, by selectively enhancing the molecular vibrations of the molecular platform, via a combination of graphene-enhanced Raman spectroscopy (GERS) and surface-enhanced Raman spectroscopy (SERS), we were able to determine the orientation of self-assembled molecular platforms with respect to the surface normal. The selective enhancement of the vibrational modes occurs by taking advantage of the distance dependence of the Raman enhancement either by the graphene surface (GERS) or the silver nanoparticules (SERS) that are located on top of the self-assembled monolayer.
功能化二维材料（2DMs）因其在纳米级器件中的应用前景而备受关注。制备具有高度有序性的连续且均匀的表面组装体一直具有挑战性。在这项工作中，我们证明通过在二维材料上非共价自组装分子平台，可以生成高质量且高度有序的单层膜。通过包括飞行时间二次离子质谱、扫描隧道显微镜、X射线光电子能谱和原子力显微镜在内的多种分析技术，证实了自组装单分子层的高度有序性和均匀性。此外，通过结合石墨烯增强拉曼光谱（GERS）和表面增强拉曼光谱（SERS）选择性增强分子平台的分子振动，我们能够确定自组装分子平台相对于表面法线的取向。振动模式的选择性增强是通过利用位于自组装单分子层顶部的石墨烯表面（GERS）或银纳米颗粒（SERS）的拉曼增强的距离依赖性来实现的。
