Efficient blue fluorescent emitters based on imidazole-pyridine derivatives for organic light-emitting diodes

Imidazole-pyridine derivatives such as 2-(1-phenyl-5-(pyridin-2-yl)-1H-imidazol-4-yl)pyridine were synthesized for the efficient blue light-emitting materials. OLED devices using these materials were fabricated in the following sequence; Indium tin oxide (ITO) (150 nm)/N,N'-diphenyl-N,N'-(2-napthyl)-(1,1'-phenyl)-4,4'-diamine (NPB) (50 nm)/Tris(4-carbazoyl-9-ylphenyl)amine (TCTA) (10 nm)/Blue materials (20 nm)/2,2 ',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) (30 nm)/Lithium quinolate (Liq)/Aluminum (Al) (2/100 nm). Particularly, a device using 9,10-dihydro-9,9-dimethyl-10-(4-(1-phenyl-4,5-di(pyridin-2-yl)-1H-imidazol-2-yl)phenyl)acridine as a blue emitter showed maximum values of luminous efficiency, power efficiency, and external quantum efficiency of 0.21 cd/A, 0.10 lm/W, 0.26% at 20 mA/cm(2), respectively with the Commission Internationale d'enclairage (CIE) (x,y) coordinates of (0.19, 0.11) at 6.0 V.