Visible Light Emission from Semiconducting Polymer Diodes

David Braun, University of California at Santa Barbara
A. J. Heeger, University of California at Santa Barbara

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Copyright © 1991 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 Applied Physics Letters and may be found at http://dx.doi.org/10.1063/1.105039.

NOTE: At the time of publication, the author David Braun was not yet affiliated with Cal Poly.

Abstract

We report visible light emission from Shottky diodes made from semiconducting polymers, confirming the discovery by the Cambridge group [Nature 347, 539 (1990)]. Our results demonstrate that light-emitting diodes can be fabricated by casting the polymer film from solution with no subsequent processing or heat treatment required. Electrical characterization reveals diode behavior with rectification ratios greater than 104. We propose that tunneling of electrons from the recitifying metal contact into the gap states of the positive polaron majority carriers dominates current flow and provides the mechanism for light emission.