Efficient Organic Light-Emitting Diodes Based on Indeno-Type Polyaromatic Hydrocarbons.

To develop the efficient emitters for organic light-emitting diode (OLED), three indeno-type polyaromatic hydrocarbons materials were designed and synthesized through Buchwald-Hartwig amination. OLED devices using these materials were fabricated in the following sequence: indium-tin-oxide (ITO) (180 nm)/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (50 nm)/Emitting materials (1-3) (30 nm)/4,7-diphenyl-1,10-phenanthroline (BPhen) (30 nm)/lithium quinolate (Liq) (2 nm)/Al (100 nm). All devices showed the efficient emissions. In particular, a device using 8,8-dimethyl-N, N-diphenyl-8H-indeno[2,1-b] fluoranthen-6-amine (2) as efficient emitter showed luminous efficiency, power efficiency, and external quantum efficiency of 8.35 cd/A, 5.70 lm/W, 2.37% at 20 mA/cm(2), respectively, with Commission Internationale d'Enclairage (CIE) coordinates of (0.37, 0.59) at 6.0 V.