Translator Disclaimer
Paper
4 April 1997 Materials and modeling for organic light-emitting diodes
Author Affiliations +
Abstract
Polymer light-emitting diodes, based for example on MEH-PPV, are known to be susceptible to oxidative degradation. This leads to loss of conjugation, i.e. lower carrier mobility and higher operating voltage, and to the formation of carbonyl species, i.e. to luminescence quenching. In-situ FTIR has revealed that ITO can act as the source of oxygen. In order to explore further the mechanism of oxidation and to provide guidance for its elimination, we have studied the behavior of MEH-PPV LEDs prepared with a variety of conducting polymer anodes including polyaniline and polythiophene derivatives cast from various solvents and with various molecular and polymeric dopants. In all cases examined, it is found that polymer anodes lead to significant improvement in lifetime over devices with ITO as the anode contact. Moreover, in contrast to the variability observed for ITO anodes, conducting polymers with polymers with polymeric dopants yield consistently good devices with power efficiencies of about 0.5 percent at 5 volts and brightness in excess of 1000 cd/m2. Anodes prepared with small molecule dopants are more variable and exhibit short term behavior which suggests interfacial electrochemistry. We describe the device characteristics in the context of a model of hole-dominated bipolar charge injection with Langevin recombination.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Campbell Scott, Sue A. Carter, Siegfried Karg, and Marie Angelopoulos "Materials and modeling for organic light-emitting diodes", Proc. SPIE 3002, Light-Emitting Diodes: Research, Manufacturing, and Applications, (4 April 1997); https://doi.org/10.1117/12.271028
PROCEEDINGS
6 PAGES


SHARE
Advertisement
Advertisement
RELATED CONTENT

New conjugated polymer (PININE) with stability for LEDs
Proceedings of SPIE (October 16 2007)
Novel blue light-emitting polymers for PLED
Proceedings of SPIE (November 10 2004)
High-efficiency polymer LEDs : triplets and novel devices
Proceedings of SPIE (September 08 2004)
LEDs based on conjugated PPV block copolymers
Proceedings of SPIE (November 01 1996)

Back to Top