Chemical tuning of electroluminescence copolymers to improve emission efficiencies and allow patterning

• Published in: Nature (London) Vol. 356; pp. 47 - 49
• Main Authors: Burn, P L, Holmes, A B, Kraft, A, Bradley, D D C, Brown, A R, Friend, R H, Gymer, R W
• Format: Journal Article
• Language: English
• Published: 05.03.1992
• ISSN: 0028-0836

It has been found that electroluminescent copolymers comprising a combination of different arylene units can be chemically tuned to provide a range of materials with considerably improved properties for use as the active layers in light-emitting diodes and other applications. One of two different leaving groups incorporated into a precursor copolymer can be selectively eliminated to give a conjugated/nonconjugated copolymer, or both can be eliminated to give a fully conjugated copolymer. This permits local variation in the pi-pi* electronic energy gap to be induced at both the molecular and supramolecular levels. Variations at the molecular level can act to trap excitons, hindering their migration to quenching sites; these materials give strongly enhanced quantum yields for electroluminescence and allow control of the color of emission. Variations at the supramolecular level permit the production of structures suitable for multicolor displays. The ability to pattern the film allows fabrication of optical waveguides. (C.D.)