Synthesis and Photoelectric Properties of a New Phosphorescent Host Material Based on Carbazole

A new phosphorescent host material based on 9-[6-(9H-carbazol-9-yl)hexyl]-9H-carbazole (hCP) was designed and synthesized and its structure and properties were characterized. These investigations indicated that hCP possessed a twisted rigid structure, with the two carbazole units in a non-coplanar conformation leading to a higher triplet energy level (3.01 eV). hCP also possessed a high glass transition temperature (93 °C). Electroluminescent devices were fabricated by doping the hCP host with the green- phosphorescent fac-tris(2-phenylpyridine)iridium(III) (Ir(ppy) 3 ) as the light-emitting layer. Compared with devices employing the typical (4,4 -N,N -dicarbazole)biphenyl) (CBP) as a host, the hCP host showed a 34.8% increase of current efficiency to 15.1 cd · A -1 .