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Proceedings Paper

Columnar discotics for light-emitting diodes
Author(s): Volker Stuempflen; Inga Stapff; Joachim Heinz Wendorff
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Paper Abstract

Polymer and low molar mass liquid crystalline discotic materials display an unusually large hole mobility of the order of 10-2 cm2/VS which results from the formation of stacks with a strong one dimensional (pi) - electron overlap. Homogeneous films with the stacks being uniformly oriented along the film normal or perpendicular to it can be prepared by spin coating and multilayer films with a narrow control of the internal structure via Langmuir Blodgett techniques. We have used such discotic materials as hole transport layer in light emitting diodes both in single layer as well as in multilayer devices. The observation is that the onset fields are small compared with amorphous hole conducting materials, that the onset fields depend strongly on the orientation of the molecular stacks and finally that the onset field is significantly decreased and the quantum efficiency increased in the multilayer devices. Quantum well structures are available via the Langmuir Blodgett technique.

Paper Details

Date Published: 17 April 1998
PDF: 9 pages
Proc. SPIE 3281, Polymer Photonic Devices, (17 April 1998); doi: 10.1117/12.305418
Show Author Affiliations
Volker Stuempflen, Philipps-Univ. Marburg (Germany)
Inga Stapff, Philipps-Univ. Marburg (Germany)
Joachim Heinz Wendorff, Philipps-Univ. Marburg (Germany)

Published in SPIE Proceedings Vol. 3281:
Polymer Photonic Devices
Bernard Kippelen; Donal D. C. Bradley, Editor(s)

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