Strength and plasticity in small volumes (Prof DJ Dunstan)
This is an on-going EPSRC-supported research programme in collaboration with the Materials Department in which we are establishing why all materials are stronger when plasticity is confined to small volumes, as in nanoindentation, or when micron-sized components are stressed. New experiments have been designed to measure the stress-strain curves for thin foils and wires, and more experimental data is needed. There is opportunity also for students to work on theoretical developments, on exploitation, and on related outreach.
Intrinsic spin and charge carrier dynamics in organic semiconductors (Dr AJ Drew)
The importance and performance of organic electronic devices have increased significantly in the last two decades, and are increasingly showing great promise for new applications. A novel class of techniques makes use of a spin probe to measure the motion of charge carriers and their spin relaxation. Muon spin relaxation (muSR) has the unique feature that in organic materials it can both generate an excitation by chemical reaction with the system and also act as a sensitive probe of the dynamics of this excitation. Thus far, the application of muSR to investigating charge carrier transport in organic materials has been mostly limited to conducting polymers and has not been widely applied to small molecular systems. Furthermore, there has been little work on using muons to measure intrinsic electron spin dynamics. This project aims to develop the muSR technique in these areas and will involve combining the expertise in muon science with materials science, chemistry, physics and molecular electronics. This multi-disciplinary approach guaranties an unrivalled chance of unravelling the intricacies of intrinsic molecular charge and spin dynamics, which is critical to future applications of these already technologically relevant materials. Considerable travel will be associated with this project, as the main experimental work is carried out at world-leading research facilities spread across Europe and beyond.
Organic magnetoresistance (Dr WP Gillin)
It has recently been demonstrated that magnetic fields can have dramatic effects upon the current in and efficiency of organic light emitting diodes and organic photovoltaic cells. This is due to the fact that electron spin is vitally important in all of these devices and a magnetic field acts to perturb spin interaction processes. The study of this phenomena has led us to an improved understanding of the operation of these devices and in particular to the role that excited states have on charge transport. This project will involve performing a detailed study of the effect of magnetic fields on a number of OLEDs. The project will involve growing devices using our state-of-the-art facilities and then characterising these devices under various magnetic fields.