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Proceedings Paper

Impact of the metal cathode on the performance of polymer light-emitting diodes
Author(s): Matthias Stoessel; Georg Wittmann; Karsten Heuser; Joerg Blaessing; Jan Birnstock; W. Rogler; W. Roth; A. Winnacker; Michael Inbasekaran; Mark T. Bernius; Weishi W. Wu; James J. O'Brien
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Paper Abstract

An appropriate choice of the cathode material and the process of cathode deposition is a key issue in the development of polymer light emitting devices. In this paper, we report on the impact of low work function metals on the luminescence efficiency of thin films of polyfluorene type polymers. Photoluminescence as well as electroluminescence experiments are presented, and in both cases, a strong correlation between the metal layer thickness and the luminescence efficiency is demonstrated. By means of time-of-flight secondary ion mass spectroscopy (TOF-SIMS), the distribution of the metal contamination within the polymer layers is determined. The results strongly suggest that impurity quenching of excitons by metal atoms inside the polymer layer takes place and strongly affects luminescence and device efficiency.

Paper Details

Date Published: 2 February 2001
PDF: 8 pages
Proc. SPIE 4105, Organic Light-Emitting Materials and Devices IV, (2 February 2001); doi: 10.1117/12.416880
Show Author Affiliations
Matthias Stoessel, Siemens AG (United States)
Georg Wittmann, Siemens AG (Germany)
Karsten Heuser, Siemens AG (Germany)
Joerg Blaessing, Siemens AG (Germany)
Jan Birnstock, Siemens AG (Germany)
W. Rogler, Siemens AG (Germany)
W. Roth, Siemens AG (Germany)
A. Winnacker, Friedrich-Alexander Univ. Erlangen-Nuernberg (Germany)
Michael Inbasekaran, The Dow Chemical Co. (United States)
Mark T. Bernius, The Dow Chemical Co. (United States)
Weishi W. Wu, The Dow Chemical Co. (United States)
James J. O'Brien, The Dow Chemical Co. (United States)

Published in SPIE Proceedings Vol. 4105:
Organic Light-Emitting Materials and Devices IV
Zakya H. Kafafi, Editor(s)

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