2009 Faraday medal

Professor Donal Bradley

Imperial College London

For his pioneering work in the field of ‘plastic electronics’, His experimental investigations have significantly advanced our understanding of the physics of conjugated polymers as semiconductors and helped to demonstrate their widespread application potential.

Donal Bradley has made seminal contributions to the science and engineering of plastic semiconductors, focussing on critical control of optoelectronic properties via chemical and physical structure. His work has helped to establish and understand the trade-offs between processing protocols and ultimate performance, yielding a much deeper knowledge of these novel materials and allowing plastic electronics to emerge as an important new branch of condensed matter physics. In turn this has facilitated device optimisation, driving an increased commercial interest in market sectors spanning displays, lighting, electronics, solar energy and medical diagnostics.

Bradley and colleagues have explored in detail the influence of conformation, configuration, packing, and alignment, helping to separate intrinsic and extrinsic factors and emphasising the importance of molecular control. Major contributions have also been made to broader materials processing and device fabrication advances and to the development of sophisticated optical probes.

Bradley’s initial materials focus in Cambridge was on precursor-route polyarylenevinylenes, work that led to the patented invention of conjugated polymer electroluminescence, to the founding of Cambridge Display Technology (CDT) and to rapid growth in global plastic electronics activity. On moving to Sheffield, Bradley built up close links with The Dow Chemical Company and through an influential sequence of publications helped to establish the polyfluorenes’ (PFs) credentials for LED and other applications. The Sumitomo Chemical Company (which acquired Dow’s PF business and then bought CDT) has continued the interaction on PFs with Bradley, now at Imperial College London. Further strong collaborations have emerged in the solar energy arena with, for example, Merck Chemicals.

Other key themes in Bradley’s published research include charge injection and transport, photophysics, optical gain and lasing, nonlinear optical spectroscopy, hybrid organic/ inorganic semiconductor structures, microcavities operating in both the weak- and strong-coupling regimes and microfluidic chip based diagnostic devices, the latter involving close links with Molecular Vision Ltd (a second start-up co-founded by Bradley).