Exploiting Dual Emission from Single Polymers to Achieve Highly-efficient, Colour-tunable and White Organic Light-Emitting Devices

Organic light-emitting devices (OLEDs) use polymers with structures built up from conjugated rings and pi-electrons to convert electrical energy into visible light. The organics offer brighter and more efficient displays than are available using current LED technology; they are easier to manufacture and the substrates for their deposition can be flexible plastic. The new materials to be studied in this project are based on a family of light-emitting organic polymers called polyfluorenes. Synthetic chemistry techniques will enable us systematically to modify the chemical structure of the polymer with the result that the colour of the emitted light will change in a controlled way. A particular goal of this new technology which we will address is to tailor the chemical structure of the polymer so that white light is emitted. This is something which could hardly have been even dreamt of 10 years ago! New sources of white light are potentially of great benefit to society and the economy. Light bulbs are based on technology which is about 100 years old; fluorescent tubes are more efficient, but they are fragile, ugly and not well suited to home use. Lighting accounts for more than 20% of the UK's energy consumption, so replacing this old technology with new more efficient sources is a high priority, with potentially great benefit to the general public and the environment.This adventurous interdisciplinary project will combine organic synthesis, photophysical studies, device fabrication and measurements of the device properties. We plan to produce a new generation of materials for OLEDs, to understand their fundamental photophysical properties and to demonstrate devices which will be applicable to commercialisation in electronic display technologies, including solid state lighting.