We are working on a new class of hybrid material that is so thin it is both a surface and an interface. These are oxide films that are one atomic layer thick and can be imaged in the scanning tunnelling microscope (STM) with atomic resolution. The structure of the films is unique to the thin film system, is not a bulk termination, and is determined through the interaction with the gold substrate. To date we have explored TiOx, NbOx, VOx, and FeOx films on Au(111) crystal substrates. The new project in this area will concentrate on ternary oxide films such as FeCrOx. These systems are of fundamental importance to understanding the effects of high temperature encapsulation of noble metal catalysts. Particular emphasis will be placed on learning about point and extended defects that occur in the films as well as investigating the properties and atomic structure of preferential molecular adsorption sites.

This project involves the growth of 2D conducting metal-organic frameworks (MOFs) in ultra-high vacuum (UHV) and subsequent characterisation with atomic resolution using scanning tunnelling microscopy (STM). Conductive 2D MOF networks result from square planar complexation of late transition metals and some simple polyaromatic hydrocarbon ligands. We grow these MOFs in-situ by evaporating elemental metals (e.g. Cu, Ni, Co) and molecules (e.g. HHTP, HATP, HHB) onto an Au(111) surface. Annealing in UHV leads to a complexation reaction of the metals with the molecules. We are currently interested in observing this reaction as well as exploring alternative metal and ligand combinations. Within the context of gas sensing we are particularly interested in the interaction of the MOFs with small reactive molecules such as ammonia and nitrogen oxides.

Molecular imaging and theoretical modelling of 2D nucleotide base networks
(in collaboration with Dr Christopher Patrick, University of Warwick)

This is a joint experiment / theory project that will suit a student willing to take on the challenge of mastering scanning tunnelling microscopy (STM) and density functional theory (DFT) modelling. 2D molecular networks will be synthesised in ultrahigh vacuum through self-assembly on metal surfaces such as Au(111). STM is used to investigate the ordering of the molecules. DFT is then employed to calculate the relative energies of viable network configurations to gain further insights into the physical interactions that drive self-assembly. Of particular interest are interactions that influence the chirality (handedness) of the molecular arrangements. Examples of this are networks that consist of DNA and RNA nucleobases such as adenine and uracil. This project is relevant to the broader issue of the physical mechanisms that are responsible for the ordering of biomolecules such as nucleotide bases and amino acids. Within this context the project will contribute to the field of abiogenesis.

The aim of the work in this project is to develop sensing technology that can be readily miniaturised and provide lightweight mobile or networked molecular detection of chemicals in the vapour phase. In Oxford we have been working on developing such sensors through research into the use of conducting polymer networks or metal-organic frameworks (MOFs) operating in the electrical percolation region, which we refer to as percolation sensors. This project involves the development of percolation sensors for the detection of a variety of analytes, especially volatile organic compounds. The student will be involved in a broad range of interdisciplinary activities including design, characterisation, and testing of the gas sensor. The sensors can be grown on a variety of substrates including rigid glass and high-area flexible polymer sheets.