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%): Alq3 (20 nm)/Alq3 (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 1.25 lm/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.