Graded-host phosphorescent light-emitting diodes with high efficiency and reduced roll-off
Date
2012Source Title
AIP Advances
Print ISSN
2158-3226
Electronic ISSN
2158-3226
Publisher
A I P Publishing LLC
Volume
2
Issue
1
Pages
012192-1 - 012192-7
Language
English
Type
ArticleItem Usage Stats
296
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240
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Abstract
We demonstrated graded-host phosphorescent organic light-emitting diodes with high efficiency and reduced efficiency roll-off. The emissive layer of the graded host device consists of both electron and hole transport type hosts, 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBI) and 4,4-,4- tris(Ncarbazolyl) triphenylamine, respectively, with graded composition, and the phosphorescent red emitter bis(2-phenylquinoline) (acetylacetonate) iridium(III), which wasuniformly doped into the graded hostmatrix. The graded host device shows improved quantum efficiency and power efficiency with significantly reduced efficiency rolloff as compared to the unipolar-host and double layer heterojunction host devices.
Keywords
AcetylacetonatesDouble layers
Emissive layers
Graded composition
Hole transports
Host devices
Phosphorescent organic light-emitting diodes
Power efficiency
Red emitter
Triphenyl amines
Benzene
Heterojunctions
Iridium compounds
Light emission
Light emitting diodes
Phosphorescence
Efficiency