Abstract
Polymeric light emitting devices may be fabricated from a simple structure consisting of a low work function cathode (typically calcium or magnesium), a conjugated semiconducting polymer and a transparent anode (typically indium-tin oxide). Optimum device efficiencies require the balanced injection of electrons and holes. This paper describes the application of molecular engineering in the design of a family of poly(cyanoterephthalylidenene)s which show increased electron affinity over the unsubstituted analogue [poly(p-phenylenevinylene) PPV]. In particular these polymers as the emissive layer in a bilayer device with indium tin oxide (ITO, positive transparent contact) and aluminum (stable negative contact) and PPV as a hole transporting layer exhibit internal efficiencies up to 4%.
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Acknowledgments
We thank the Science and Engineering Research Council (U.K.), Cambridge Research & Innovation Limited, and Cambridge Display Technology for supporting this work. We thank Clare College, Cambridge for the award of the Denman Baynes Studentship (NCG) and the Royal Society for the award of a Royal Society Leverhulme Senior Research Fellowship (ABH). We thank ICI Paints (Slough) for assistance with the DSC measurements.
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Moratti, S.C., Bradley, D.C., Friend, R.H. et al. Molecularly Engineered Polymer LEDs. MRS Online Proceedings Library 328, 371–376 (1993). https://doi.org/10.1557/PROC-328-371
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DOI: https://doi.org/10.1557/PROC-328-371