Highly Efficient Blue-Light-Emitting Diodes from Polyfluorene Containing Bipolar Pendant Groups

Autor:	Ching-Fong Shu, Rajasekhar Dodda, Michelle S. Liu, Fang-Iy Wu, Alex K.-Y. Jen
Rok vydání:	2003
Předmět:	Photoluminescence Materials science Polymers and Plastics Organic Chemistry Quantum yield Electroluminescence Fluorene Triphenylamine Photochemistry Inorganic Chemistry chemistry.chemical_compound Polyfluorene chemistry Materials Chemistry Side chain Quantum efficiency
Zdroj:	Macromolecules. 36:6698-6703
ISSN:	1520-5835 0024-9297
DOI:	10.1021/ma030123e
Popis:	A highly efficient blue-light-emitting copolymer with bulky hole-transporting triphenylamine (TPA) and electron-transporting oxadiazole (OXD) pendant groups at the C-9 position of fluorene was synthesized. The results from photoluminescence and electrochemical measurements reveal that both the side chains and the polyfluorene main chain retain their own electronic characteristics in the copolymer. It shows a pure blue emission with no aggregates or excimers formed even after being annealed at 150 °C under nitrogen for 20 h. In addition, it also demonstrates improved charge injection and balanced charge transport in electroluminescence. The maximum external quantum efficiency of a single-layer device using this copolymer as the emitting layer is 1.21% (at a brightness of 354 cd/m2 with driving voltage of 7.6 V). The maximum luminance of the device reaches 4080 cd/m2 at a bias of 12.0 V and a current density of 640 mA/cm2.
Databáze:	OpenAIRE
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