Red Fluorescent Organic Light-Emitting Diodes Using Modified Pyran-containing DCJTB Derivatives

Two red fluorescent DCJTB derivatives (Red 1 and 2) based on modified pyrans were synthesized and their electroluminescent properties were investigated. Multilayered OLEDs were fabricated with the device structure of ITO/NPB (40 nm)/Red 1, 2 or DCJTB (0.5 or 1%): Alq(3) (20 nm)/Alq(3) (40 nm)/Liq (2 nm)/Al. All devices exhibited efficient red emissions. In particular, a device containing emitter Red 2 as a dopant in the emitting layer, the maximum luminance was 8737 cd/m(2) at 12.0 V, the luminous and power efficiencies were 2.31 cd/A and 1.251m/W at 20 mA/cm(2), respectively. The peak wavelength of the electroluminescence was 638 nm with the CIE (x,y) coordinates of (0.63, 0.36) at 7.0 V.