Towards OCPLEDs: Organic Circularly Polarised Light Emitting Devices

Organic light emitting diodes (OLEDs) require an emissive electroluminescent layer of an organic semiconductor material located between two electrodes, where at least one of the electrodes is transparent. Such devices are revolutionising display technologies, with the production of flexible and fully transparent devices possible. Devices that emit circularly polarised electroluminescence (CPEL) should have vast translational potential in photonic technology, such as highly improved LCD backlighting, colour-image detection and stereoscopic displays, optical communication, and quantum computing, however to date the problem of directly generating CPEL has not been solved. The goal of this research is to use intrinsically chiral, conductive and luminescent small molecules as electroluminescent layer in OLEDs, in an attempt to demonstrate efficient CPEL. Such work would have significant impact on current knowledge, which could be exploited in a number of translational areas. Taking alternative LCD backlighting as one example of the exploitation of this work, current technologies rely on polarising filters that effectively cut out 75% of the light used in these displays. Combined with absorption by the colour filters and at device interfaces, only 4% of the light used is transmitted. The use of a polarised light source, coupled with tuneable colour components would remove this need, thus leading to significantly more energy efficient displays, with a dramatically lowered carbon footprint.

The science proposed herein would have significant impact on current academic and industrial knowledge in a diverse range of disciplines including chemistry, physics and materials science. Indeed, advances in the direct generation of CPEL would have international impact in these fields, and is likely to promote new research directions. The translational aspect of this proposal would be of high interest to a number key industrial companies (CDT, Merck, BASF, etc) involved in plastic electronics research. Technological advances resulting from this work would have clear ramifications in terms of wealth creation within the UK, with, for example, the current OLED market valued at >$2.5B. Taking alternative LCD backlighting as one example of the exploitation of this work (as highlighted in the proposal), a novel polarised light source, coupled with tuneable colour components would lead to significantly more energy efficient displays. Such displays with a lowered carbon footprint would be of clear environmental impact, and therefore of benefit to society as a whole. Finally, further training of skilled-coworkers and the educational experiences of students involved in this science would also have clear economic and societal impact.