Probing Molecules Confined Between Graphene and Other 2D Materials

理解由静电和电动力学相互作用控制的分子组织和动力学需要在分子水平上测量介电极化。然而，这仍然是一个技术挑战，因为现有的大规模技术，如宽带介电光谱[1]的灵敏度有限。此外，尽管在原子计算方面取得了进步，理论家们仍难以预测当系统接近分子大小时的介电极化[2,3]。本研究项目的重点是利用扫描探针技术在纳米尺度上测量分子的介电特性[4,5]。特别是，我们将通过实验确定纳米受限分子的介电特性，与散装分子的介电特性相比，纳米受限分子的介电特性预计会有显著差异[2,3]。为此，在博士项目的第一年，我们将探索使用二维（2D）材料对分子[6]进行物理限制的可能性，并通过开发和使用定制的扫描探针方法[5]，以非微扰的方式在纳米尺度上探测它们的介电特性。该项目的第一部分将需要开发适合介电测量的特殊2D样品。然后，我们将使用各种实验技术（光学显微镜，电子显微镜和原子力显微镜）对它们进行结构表征。之后，将进行纳米尺度的介电测量，以研究受约束分子的介电性质。工作预计将使用国家石墨烯研究所（NGI）的设施进行。

Understanding molecular organization and dynamics which are governed by electrostatic and electrodynamics interactions requires the measurement of dielectric polarization at the molecular level. Yet, this has remained a technical challenge owing to the limited sensitivity of available large-scale techniques such as broadband dielectric spectroscopy [1]. Furthermore, despite the advances in atomistic calculations, theorists struggle to predict dielectric polarization when the system approaches molecular sizes [2,3]. This research project focuses on the measurement of dielectric properties of molecules at the nanoscale by using scanning probe techniques [4,5]. In particular, we will experimentally determine the dielectric properties of nanoconfined molecules which are expected to differ markedly as compared to the dielectric properties of molecules in bulk [2,3]. To this end, during the first year of the PhD project, we will explore the possibility of using two-dimensional (2D) materials to physically confine the molecules [6] and probe their dielectric properties at the nanoscale and in a non-perturbative way by developing and using customized scanning probe approaches [5].This first part of the project will require the development of special 2D samples suitable for dielectric measurement. We will then structurally characterize them using a variety of experimental techniques (optical microscopy, electron microscopy and atomic force microscopy). After that, nanoscale dielectric measurements will be carried out to study the dielectric properties of the confined molecules. Work is expected to be carried out using the facilities of the National Graphene Institute (NGI).