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Residual Halide Groups in Gilch-Polymerized Poly(p-phenylene-vinylene) and Their Impact on Performance and Lifetime of Organic Light-Emitting Diodes

Fleissner, Arne and Stegmaier, Katja and Melzer, Christian and von Seggern, Heinz and Schwalm, Thorsten and Rehahn, Matthias (2009):
Residual Halide Groups in Gilch-Polymerized Poly(p-phenylene-vinylene) and Their Impact on Performance and Lifetime of Organic Light-Emitting Diodes.
21, In: Chemistry of Materials, (18), pp. 4288-4298, ISSN 0897-4756, [Online-Edition: http://dx.doi.org/10.1021/cm901513k],
[Article]

Abstract

On the basis of new insights into the reaction mechanism of the so-called Gilch route leading to poly(p-phenylene-vinylene)s (PPVs), the importance of vinyl halide defects for the performance of organic light-emitting diodes (OLEDs) is stressed in the present contribution. It is found that the current density, the luminance, and luminance efficiency are superior for PPVs that were subject to a long-term dehydrohalogenation. In particular, the device lifetime improves by a factor of 200 as long as the halide content is reduced from 0.4 to 0.05 wt %. The results imply that rather the mentioned vinyl halide defect than the often discussed tolane-bisbenzyl (TBB) defect has to be considered when investigating lifetime and performance of OLEDs. The device behavior is analyzed in view of a detailed study of the charge-carrier transport properties. We suggest that the penetration of electrons from the cathode in the PPV leads to a separation of halogen and thus to free halogen anions. The anions can move in the electric field to the contacts where they form a salt with the counterion present in the electrode material. The charge-carrier transport across the respective contact is thus impeded as a consequence of the appearance of a salt-containing interlayer. The proposed mechanism explains the observed differences in device performance and lifetime.

Item Type: Article
Erschienen: 2009
Creators: Fleissner, Arne and Stegmaier, Katja and Melzer, Christian and von Seggern, Heinz and Schwalm, Thorsten and Rehahn, Matthias
Title: Residual Halide Groups in Gilch-Polymerized Poly(p-phenylene-vinylene) and Their Impact on Performance and Lifetime of Organic Light-Emitting Diodes
Language: English
Abstract:

On the basis of new insights into the reaction mechanism of the so-called Gilch route leading to poly(p-phenylene-vinylene)s (PPVs), the importance of vinyl halide defects for the performance of organic light-emitting diodes (OLEDs) is stressed in the present contribution. It is found that the current density, the luminance, and luminance efficiency are superior for PPVs that were subject to a long-term dehydrohalogenation. In particular, the device lifetime improves by a factor of 200 as long as the halide content is reduced from 0.4 to 0.05 wt %. The results imply that rather the mentioned vinyl halide defect than the often discussed tolane-bisbenzyl (TBB) defect has to be considered when investigating lifetime and performance of OLEDs. The device behavior is analyzed in view of a detailed study of the charge-carrier transport properties. We suggest that the penetration of electrons from the cathode in the PPV leads to a separation of halogen and thus to free halogen anions. The anions can move in the electric field to the contacts where they form a salt with the counterion present in the electrode material. The charge-carrier transport across the respective contact is thus impeded as a consequence of the appearance of a salt-containing interlayer. The proposed mechanism explains the observed differences in device performance and lifetime.

Journal or Publication Title: Chemistry of Materials
Volume: 21
Number: 18
Divisions: DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A5: Synthesis of semiconducting model polymers and their characterization before and after cyclic electrical fatigue
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > D - Component properties > Subproject D4: Fatigue of organic electronic devices
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > D - Component properties
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 04 Aug 2011 12:50
Official URL: http://dx.doi.org/10.1021/cm901513k
Additional Information:

SFB 595 Cooperation A5, D4

Identification Number: doi:10.1021/cm901513k
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