Efficient blue organic light emitting diodes based on 14,14-dimethyl-14H-indeno[1,2-b]triphenylene derivatives

Abstract

We synthesized and characterized blue emitting materials based on indeno-triphenylene derivatives. Multilayer organic light emitting diodes (OLEDs) were fabricated in the following sequence; ITO (180 nm)/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (50 nm)/Blue emitter (30 nm)/4,7-diphenyl-1,10-phenanthroline (BPhen) (30 nm)/lithium quinolate (Liq)/Al (2 nm/100 nm). Particularly, a device using 14,14-dimethyl-14H-indeno[1,2-b]triphenylene as an emitter showed the efficient emission and exhibited luminous efficiency, power efficiency, and external quantum efficiency of 11.16 cd/A, 6.05 lm/W, 4.30% at 20 mA/cm2, respectively. Also, it exhibited blue emission with the Commission Internationale De L'enclairage (CIE) coordinates of (0.21, 0.43) at 8.0 V.