Electroluminescence and Electrical Transport in Poly(3-Octylthiophene) Diodes

David Braun, University of California at Santa Barbara
G. Gustafsson, University of California at Santa Barbara
D. McBranch, University of California at Santa Barbara
A. J. Heeger, University of California at Santa Barbara

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Copyright © 1992 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics and may be found at http://dx.doi.org/10.1063/1.351834.

Abstract

We report visible light emission from diodes made from poly(3-octylthiophene). Use of a soluble derivative of polythiophene allows fabrication of the light emitting diodes by casting the polymer film from solution with no subsequent processing or heat treatment required. The devices emit dim red-orange light with relatively low external quantum efficiencies, below 2.5×10⁻⁵ photons per electron at room temperature. Electrical characterization reveals diode behavior with rectification ratios greater than 10². The temperature dependence indicates that tunneling phenomena dominate the charge injection.