Synthesis and electroluminescent properties of carbazolyl vinylene derivatives

We report the photo-(PL) and electro-luminescence (EL) properties of conjugated compounds based on carbazolyl vinylene moiety, 3,3′-(1,4-phenylene di-2,1-ethenediyl)bis[9-ethyl-(E,E)-9H-carbazole] (PEEC) and 3,3′-([1,1′-biphenyl]-4,4′-diyldi-2,1-ethenediyl)bis[9-ethyl-9H-carbazole] (BPEEC), as emitting materials. The ITO/m-MTDATA/NPB/BPEEC/AlQ3/LiF/Al device shows bluish-green EL spectrum at 490 nm and turn-on voltage at 8 V. PEEC also shows bluish-green EL spectrum at 496 nm and turn-on voltage at 6 V and 2.4 cd/A efficiency in ITO/m-MTDATA/NPB/PEEC/AlQ3/LiF/Al device. ITO/m-MTDATA/NPB/DPVBi + PEEC (3%)/AlQ3/LiF/Al device shows EL spectrum at 462 nm and EL efficiency was increased to 4.5 cd/A (1.7 lm/W) from 3.5 cd/A (the device without doping agent).