Article contents
Singlet Exciton Quenching by Radical Cations of Aromatic Diamines as an Electron Donor in Organic Electroluminescent Devices
Published online by Cambridge University Press: 02 March 2011
Abstract
In this study, we report the luminescence quenching by radical cations of aromatic diamines used as a hole transport layer (HTL) in organic electroluminescent (EL) devices. The EL characteristics of green organic EL devices with an electron transport layer (ETL) as an emitter i.e. ITO/TPD HTL/Alq3 ETL/Al is studied. Here, ITO, TPD, and Alq3 are abbreviations for indium-tin-oxide, N,N’-diphenyl-N,N’-bis(3-methylphenyl)-1,1’-biphenyl-4,4’-diamine, and tris (8-hydroxyquinoline) aluminum, respectively. UV-visible absorption and electrochemical data indicate the formation of radical cations in thin film and solution of TPD after chemical oxidation. We find that the EL luminance increases less than linearly with an increase in current for the EL devices studied in this study. The luminance loss in the devices is attributed to quenching of singlet excited states by large excess radical cations of TPD are accumulated in the emission zone due to large overlap between a flourescence spectrum of Alq3 and an absorption spectrum of radical cations of TPD.
- Type
- Research Article
- Information
- MRS Online Proceedings Library (OPL) , Volume 1286: Symposium E – Molecular and Hybrid Materials for Electronics and Photonics , 2011 , mrsf10-1286-e03-15
- Copyright
- Copyright © Materials Research Society 2011
References
REFERENCES
- 1
- Cited by