Rational design of 2D materials

The aim of this course is to lay the foundation for experimental and theoretical work that forms the basis for designing 2D materials with desired functionalities. The approach falls under the umbrella of the Materials Genome Initiative (MGI) in which theory and experiments work in a feedback loop with information from one used to better the other, to accelerate the discovery of novel materials. It is addressed to physics and chemistry students at all stages and senior scientists who are interested in understanding and predicting the characteristics of functional 2D materials. The specific direction and scope of the course is open to discussion and may be adjusted to the interest of the audience.

There will be a short introduction into the striking properties of 2D Materials such as single-layer transition metal dichalcogenides (TMDC) and surface-coordinated molecular assemblies, vis-a-vis their applications (optoelectronic and catalysis), because of their low-dimensionality, well-defined local electronic and geometric structure, and/or intrinsic direct band-gap which typically lies in the visible spectrum. This will be followed by a summary of the opportunity and challenges, as gleaned from some of the extensive literature that has emerged in the past few years. The remaining lectures are devoted to topics specific to the two types of systems. In the case of the TMDCs, the focus will be on their band gap engineering and manipulation of their frontier orbitals through alloying, vacancy formation, hydrogenation, fluorination, interface with metallic nanostructures and alkali metal doping. Attention will also be paid to the characteristics of excitons, trions, and biexcitons in these systems. In the case of surface-coordinated molecular assemblies, the goal will be to understand the comparative roles of the functional groups and the coordination center in determining the nature of the active site.

Outline:

• Introduction to the two classes of two-dimensional functional materials
• Survey of opportunities & challenges in 2D-TMDC
• Band gap engineering in 2D-TMDC
• Manipulation of the frontier orbitals in 2D-TMDC
• 2D-TMDC as catalysts for conversion of syn-gas to methanol
• Molecular adsorption and coordinated network formation on metal surfaces
• Manipulation of the oxidation state of the metal coordination center
• Discussion of the way forward to face the challenges computationally