Blue organic light-emitting diodes with carbazole-based small molecules

We synthesized bis(3-N-ethylcarbazolyl) terephthalidene (BECP) and bis(3-N-ethylcarbazolyl) cyano-terephthalidene and characterized electroluminescence properties of these materials. Our device shows a strong blue emission at 472 nm with a luminance efficiency of 0.9 lm/W at a voltage, a current density, and a brightness of 8 V, 5.7 mA/cm2 and 130 cd/m2, respectively and shows typical rectifying diode characteristics in ITO/CuPc/TPD/BECP/Bu-PBD or Alq3/LiF/Al device.