Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-10T09:22:55.040Z Has data issue: false hasContentIssue false
  • English
  • Français

Layer Cross-Fading at Organic/Organic Interfaces in OVPD-Processed Red Phosphorescent Organic Light Emitting Diodes as a New Concept to Increase Current and Luminous Efficacy

Published online by Cambridge University Press:  31 January 2011

Florian Lindla ,
Manuel Boesing ,
Christoph Zimmermann ,
Frank Jessen ,
Philipp van Gemmern ,
Dietrich Bertram ,
Dietmar Keiper ,
Nico Meyer ,
M. Heuken  and
Holger Kalisch
...Show all authors
Florian Lindla
Affiliation:
florian.lindla@rwth-aachen.de, RWTH Aachen University, Institut für theoretische Elektrotechnik, Aachen, Germany
Manuel Boesing
Affiliation:
boesingm@gan.rwth-aachen.de, RWTH Aachen University, Institut für theoretische Elektrotechnik, Aachen, Germany
Christoph Zimmermann
Affiliation:
zimmermann@gan.rwth-aachen.de, RWTH Aachen University, Institut für theoretische Elektrotechnik, Aachen, Germany
Frank Jessen
Affiliation:
jessen@ithe.rwth-aachen.de, RWTH Aachen University, Institut für theoretische Elektrotechnik, Aachen, Germany
Philipp van Gemmern
Affiliation:
philipp.van.gemmern@philips.com, Philips Technologie GmbH, Aachen, Germany
Dietrich Bertram
Affiliation:
dietrich.bertram@philips.com, United States
Dietmar Keiper
Affiliation:
d.keiper@aixtron.com, United States
Nico Meyer
Affiliation:
n.meyer@aixtron.com, AIXTRON AG, Aachen, Germany
M. Heuken
Affiliation:
m.heuken@aixtron.com, RWTH Aachen University, Institut für theoretische Elektrotechnik, Aachen, Germany
Holger Kalisch
Affiliation:
kalisch@ithe.rwth-aachen.de, United States
Rolf H. Jansen
Affiliation:
rhj@ithe.rwth-aachen.de, United States
Get access

Abstract

The current and luminous efficacy of a red phosphorescent organic light emitting diode (OLED) with sharp interfaces between each of the organic layers can be increased from 18.8 cd/A and 14.1 lm/W (at 1,000 cd/m2) to 36.5 cd/A (+94%, 18% EQE) and 33.7 lm/W (+139%) by the introduction of a layer cross-fading zone at the hole transport layer (HTL) to emission layer (EL) interface. Layer cross-fading describes a procedure of linearly decreasing the fraction in growth rate of an organic layer during deposition over a certain thickness while simultaneously increasing the fraction in growth rate of the following layer. For OLED processing and layer cross-fading organic vapor phase deposition (OVPD) is used. The typical observation of a roll-off in current efficacy of phosphorescent OLED to higher luminance can be reduced significantly. An interpenetrating network of a prevailing hole and a prevailing electron conducting material is created in the cross-fading zone. This broadens the recombination zone and furthermore lowers the driving voltage. The concept of layer cross-fading to increase the efficacies is suggested to be useful in multi-colored OLED stacks as well.

Keywords

organicsemiconductingphysical vapor deposition (PVD)
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1154: Symposium B – Concepts in Molecular and Organic Electronics , 2009 , 1154-B05-07
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1] Kondakova, M.E. et al. , J. of Appl. Phys. (2008) 104, 094501 Google Scholar
[2] Adachi, C. et al. , Organic Electronics (2001) 2, 37 Google Scholar
[3] Kim, S.H. et al. , Appl. Phys. Let. (2008) 92, 02351 Google Scholar
[4] Boesing, M. et al. , Mat. Res. Soc. Symp. Proc. (2008) 1115, in pressGoogle Scholar
[5] Stöcker, , Taschenbuch der Physik, Verlag Harri Deutsch (2000)Google Scholar
[6] Merck, , Technical Data Sheet, not publishedGoogle Scholar
[7] Brüttig, W. Physics of Organic Semiconductors, Wiley-VCH (2005)Google Scholar