Applications of Perfluorinated Phenylenes for Organic Electroluminescent Devices

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Perfluorinated oligo(p-phenylene)s including perfluoro-p-quinquephenyl to -octiphenyl (PF-5P to -8P) have been synthesized by the organocopper cross-coupling method. Two PF-6P derivatives containing trifluoromethyl and perfluoro-2-naphtyl groups were also prepared. All compounds are colorless solids and insoluble in common organic solvents. The differential scanning calorimetry measurements indicated that they are highly crystalline solids without glass transitions. The electron-transport capabilities of perfluorinated oligo(p-phenylene)s are excellent compared with perfluorinated phenylene dendrimers. The maximum luminance of the naphtyl derivative is 19970 cd/m^2 at 10.0 V. The luminance-voltage and current-voltage characteristics of PF-7P and -8P are almost identical to those of PF-6P.Perfluoro-1, 3, 5-tris(p-quaterphenyl)benzene (PF-13Y) and perfluoro-1, 3, 5-tris(p-quinquephenyl)benzene (PF-16Y) have been synthesized and characterized. They showed higher glass transition temperatu … More res compared with perfluoro-1, 3, 5-tris(p-terphenyl)benzene (PF-1OY). Organic light-emitting diodes (OLEDs) were fabricated using these materials as the electron-transport layers. PF-13Y and -16Y are better electron-transporters than PF-1OY. The electron mobilities of PF-1OY and A1q_3 were measured by the time-of-flight technique. PF-1OY showed higher electron mobilities (10^<-4> cm2/Vs) and weaker electric field dependence compared with A1q3.One of the keys to highly efficient phosphorescent emission in organic light-emitting devices is to confine triplet excitons generated within the emitting layer. We employ starburst perfluorinated phenylenes (C60F42) as a both hole- and exciton-block layer, and a hole-transport material 4, 4, 4 -tri(N-carbazolyl) triphenylamine as a host for the phosphorescent dopant dye in the emitting layer. A maximum external quantum efficiency reaches to 19.2%, and keeps over 15% even at high current densities of 10-20 mA/cm^2, providing several times the brightness of fluorescent tubes for lighting. Less