Electroluminescence of new blue emitting materials having hexaphenylbenzene and carbazole groups

Two new deep-blue chromophores containing hexaphenylbenzene and ethylcarbazole units were synthesized. (E)-9-ethyl-3-(2-(3 ',4 ',5 ',6 '-tetraphenyl-[1,1 ':2 ',1 ''-terphenyl]-4-yl)vinyl)-9H-carbazole (6P-VC) and 3,3 '-((1E,1 ' E)-(3 ',4 ',5 ',6 '-tetraphenyl-[1,1 ':2 ',1 ''-terphenyl]-4,4 ''-diyl)bis(ethene-2,1-diyl))bis(9-ethyl-9H-carbazole) (6P-DVC) showed an ultraviolet-visible absorption at 343 nm and maximum photoluminescence emissions at 417 and 426 nm in solution. Devices doped with 6P-VC and 6P-DVC exhibited a high efficiency of 1.8 and 1.5 cd/A, and external quantum efficiency (EQE) of 3.7 and 1.9%, respectively. The respective devices employing the two materials showed EL maximum wavelengths of 429 and 428 nm. In particular, 6P-VC showed excellent Commission International de l'eclairage Coordinates (CIE) values of (0.16, 0.05).