Blue Emitters Based on 2-Styryl-9H-fluorene Derivatives End-Capped with Diarylamine for Organic Light-Emitting Diodes

초록

We synthesized 2-styryl-9H-fluorene derivatives end-capped with the various electron-withdrawing moieties-containing arylamine groups by Buchwald-Hartwig reactions. To investigate their electroluminescent (EL) properties, multilayer devices were fabricated based on following sequence: indium-tin-oxide (ITO) (180 nm)/4,4',4 ''-tris[2-naphthyl(phenyl) amino] triphenylamine (2-TNATA) (60 nm)/N,N'-di(1-naphthyl)-N, N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB) (20 nm)/2-methyl-9,10-bis(naphthalen-2-yl) anthracene (MADN): blue dopants (10%) (30 nm)/bathophenanthroline (Bphen) (30 nm)/lithium quinolate (Liq) (2.0 nm)/Al (100 nm). A device using 7-(4(((4-trifluoromethyl) phenyl)-phenylamino)) styryl)-9,9-diethyl-N-(4-(trifluoromethyl) phenyl)-N-phenyl-9-Hfluoren-2-amine as a dopant at 10% concentration in 2-methyl-9,10-bis(naphthalen-2-yl) anthracene host exhibited highly efficient blue emission with the luminous, power and external quantum efficiencies of 4.10 cd/A, 1.95 lm/W and 2.83% at 20 mA/cm(2), respectively. The maximum value of the CIE coordinates of this device were (0.15, 0.14).

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