Liquid crystal properties of dimers having two identical terminal units and a central oxyethylene spacers

ABSTRACT

In this research, we designed and synthesized blue emitting materials based on aminofluorene-substituted pyrene derivatives. Organic light-emitting diodes (OLEDs) devices using these materials were fabricated in the following sequence; ITO/N,N′-diphenyl-N,N′-(2-napthyl)-(1,1′-phenyl)-4,4′-diamine (NPB) (500 Å)/Blue emitters 1 or 2 (300 Å)/4,7-diphenyl-1,10-phenanthroline (BPhen) (300 Å)/lithium quinolate (Liq) (20 Å)/Al (1000 Å). These devices showed efficient blue emissions. Particularly, a device A using 7-(1-(2-(diphenylamino)-9,9-diethyl-9H-fluoren-7-yl)pyren-6-yl)-9,9-diethyl-N,N-diphenyl-9H-fluoren-2-amine (1) as blue emitter exhibited luminous efficiency, power efficiency, and external quantum efficiency of 2.20 cd/A, 0.80 lm/W, 1.62% at 100 mA/cm², respectively, with Commission Internationale d’Énclairage (CIE) coordinates of (0.17, 0.24) at 8.0 V.