Highly Branched Phosphorescent Dendrimers for Efficient Solution-Processed Organic Light-Emitting Diodes

Bera, Raghu N., Cumpstey, Neil, Burn, Paul L. and Samuel, I. D. W. (2007) Highly Branched Phosphorescent Dendrimers for Efficient Solution-Processed Organic Light-Emitting Diodes. Advanced Functional Materials, 17 7: 1149-1152. doi:10.1002/adfm.200600118


Author Bera, Raghu N.
Cumpstey, Neil
Burn, Paul L.
Samuel, I. D. W.
Title Highly Branched Phosphorescent Dendrimers for Efficient Solution-Processed Organic Light-Emitting Diodes
Journal name Advanced Functional Materials   Check publisher's open access policy
ISSN 1616-301X
Publication date 2007-05
Year available 2007
Sub-type Article (original research)
DOI 10.1002/adfm.200600118
Volume 17
Issue 7
Start page 1149
End page 1152
Total pages 4
Place of publication Weinheim, Germany
Publisher Wiley- VCH Verlag Gmbh
Collection year 2007
Language eng
Subject 020504 Photonics, Optoelectronics and Optical Communications
030306 Synthesis of Materials
Abstract Intermolecular interactions play a crucial role in the performance of organic light-emitting diodes (OLEDs). Here we report the photophysical and electroluminescence properties of a fac-tris(2-phenylpyridyl)iridium(III) cored dendrimer in which highly branched biphenyl dendrons are used to control the intermolecular interactions. The presence of fluorene surface groups improves the solubility and enhances the efficiency of photoluminescence, especially in the solid state. The emission peak of the dendrimer is around 530 nm with a PL quantum yield of 76% in solution and 25% in a film. The photophysical properties of this dendrimer are compared with a similar dendrimer with the same structure but without the fluorene surface groups. Dendrimer LEDs (DLEDs) are prepared using each dendrimer as a phosphorescent emitter blended in a 4,4′-bis(N-carbazolyl)biphenyl host. Device performance is improved significantly by the incorporation of an electron-transporting layer of 1,3,5-tris(2- N-phenylbenzimidazolyl)benzene. A peak external quantum efficiency of 10% (38 CdA–1) for the dendrimer without surface groups and 13% (49.8 CdA–1) for the dendrimer with fluorene surface groups is achieved in the bilayer LEDs.
Keyword Chromophores
Dendrimers
Electroluminescence
Electrophosphorescence
Light-emitting diodes, organic
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Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Chemistry and Molecular Biosciences
 
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