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Mechanisms for the enhancement of the thermal stability of organic thin films by aluminum oxide capping layers

Published online by Cambridge University Press:  01 February 2006

S. Sellner
Affiliation:
Max-Planck-Institut für Metallforschung, 70569 Stuttgart, Germany; and Institut für Theoretische und Angewandte Physik, Universität Stuttgart, 70550 Stuttgart, Germany
A. Gerlach
Affiliation:
Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford OX1 3QZ, United Kingdom
F. Schreiber
Affiliation:
Physical and Theoretical Chemistry Laboratory, Oxford University, Oxford OX1 3QZ, United Kingdom
M. Kelsch
Affiliation:
Max-Planck-Institut für Metallforschung, 70569 Stuttgart, Germany
N. Kasper
Affiliation:
Max-Planck-Institut für Metallforschung, 70569 Stuttgart, Germany; and ANKA, FZ Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany
H. Dosch
Affiliation:
Max-Planck-Institut für Metallforschung, 70569 Stuttgart, Germany; and Institut für Theoretische und Angewandte Physik, Universität Stuttgart, 70550 Stuttgart, Germany
S. Meyer
Affiliation:
III. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany
J. Pflaum
Affiliation:
III. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany
M. Fischer
Affiliation:
I. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany
B. Gompf
Affiliation:
I. Physikalisches Institut, Universität Stuttgart, 70550 Stuttgart, Germany
G. Ulbricht
Affiliation:
Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany
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Abstract

We present a detailed study of the thermal stability of organic thin films of diindenoperylene encapsulated by sputtered aluminum oxide layers. We studied the influence of capping layer thickness, stoichiometry, and heating rate on the thermal stability of capped films and their eventual breakdown. Under optimized encapsulation conditions (thick and stoichiometric capping layer), the organic films desorb only at temperatures 200 °C above the desorption of the uncapped film. Moreover, the capped organic films retain their crystalline order at these elevated temperatures, whereas they would normally (i.e., uncapped) be in the gas phase. This study therefore also shows a way of studying organic materials under temperature conditions normally inaccessible. Considering results from complementary techniques, we discuss possible scenarios for the eventual breakdown. The results have implications for the performance and long-term stability of organic devices for which stability against elevated temperatures as well as against exposure to ambient gases is crucial.

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Articles
Copyright
Copyright © Materials Research Society 2006

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