Novel scanning probe methods to manipulate and characterise molecular semiconductors for advanced applications

This project focuses on the use of advanced scanning probe microscopy (SPM) techniques to address the two main challenges of molecular electronics and spintronics. The first challenge is the need to control the orientation of semiconductor molecules on substrates, since their properties are highly anisotropic. This can be notoriously difficult as it relies on balancing intermolecular and molecule-substrate interactions, but we have recently found that surface dipoles can induce 90- degree rotation. In this project, ferroelectric substrates will be poled (on large areas and at the nanoscale, see placement), assessed using piezo-force microscopy, and used to template the growth of molecular semiconductors, whose functional properties will be assessed using Kelvin probe force microscopy. The second challenge is the understanding of fundamental properties such as charge and exciton transport in molecular materials at the nanoscale. This will be achieved by precisely defining insulating barriers of varying depths between semiconducting

domains in molecular single crystals via local anodic oxidation, and assessing charge, excitons and spin transport around the barriers.
Addressing both challenges in parallel will result in high efficiency molecule-based devices being developed.

The production and processing of materials accounts for 15% of UK GDP and generates exports valued at £50bn annually, with UK materials related industries having a turnover of £197bn/year. It is, therefore, clear that the success of the UK economy is linked to the success of high value materials manufacturing, spanning a broad range of industrial sectors. In order to remain competitive and innovate in these sectors it is necessary to understand fundamental properties and critical processes at a range of length scales and dynamically and link these to the materials' performance. It is in this underpinning space that the CDT-ACM fits.

The impact of the CDT will be wide reaching, encompassing all organisations who research, manufacture or use advanced materials in sectors ranging from energy and transport to healthcare and the environment. Industry will benefit from the supply of highly skilled research scientists and engineers with the training necessary to advance materials development in all of these crucial areas. UK and international research facilities (Diamond, ISIS, ILL etc.) will benefit greatly from the supply of trained researchers who have both in-depth knowledge of advanced characterisation techniques and a broad understanding of materials and their properties. UK academia will benefit from a pipeline of researchers trained in state-of the art techniques in world leading research groups, who will be in prime positions to win prestigious fellowships and lectureships. From a broader perspective, society in general will benefit from the range of planned outreach activities, such as the Mary Rose Trust, the Royal Society Summer Exhibition and visits to schools. These activities will both inform the general public and inspire the next generation of scientists.

The cohort based training offered by the CDT-ACM will provide the next generation of research scientists and engineers who will pioneer new research techniques, design new multi-instrument workflows and advance our knowledge in diverse fields. We will produce 70 highly qualified and skilled researchers who will support the development of new technologies, in for instance the field of electric vehicles, an area of direct relevance to the UK industrial impact strategy.
In summary, the CDT will address a skills gap that has arisen through the rapid development of new characterisation techniques; therefore, it will have a positive impact on industry, research facilities and academia and, consequently, wider society by consolidating and strengthening UK leadership in this field.