Synthesis and electro-optical properties of carbazole derivatives for organic device applications

Abstract

Two materials, DNCz and TCzPB, which contain carbazole moieties and exhibit high band gap energies, were synthesized via C{single bond}N coupling and Suzuki coupling reactions, respectively. The ionization potential and electron affinity of the synthesized TCzPB were measured at 5.89 and 2.39 eV, respectively, implying that it is suitable for a host material. A doped multilayer device, ITO/DNTPD/NPD/TCzPB + Ir(ppy)3/BCP/Alq3/LiF/Al, exhibited a bright green emission with a maximum luminance of 27,200 cd/m2 (17.6 cd/A at 18.0 V) when the synthesized TCzPB was used as the host material for a phosphorescent green dopant. The compound DNCz exhibited similar electronic energy levels to those of NPD, and was applied as a hole-transporting material. Bright green light originated from the Alq3 layer was observed in the double layer device, ITO/DNCz/Alq3/LiF/Al. The high hole-transporting property of DNCz was also demonstrated. © 2009 Elsevier B.V. All rights reserved.