Bis(arylquinoxalinyl)carbazole derivatives as saturated blue emitters for electroluminescent devices

Bis(arylquinoxalinyl)carbazole derivatives 9-phenyl-3,6-bis-(3-phenyl-quinoxalin-2-yl)-9H-carbazole (PPQC), 9-phenyl-3,6-bis-[3-(4-methoxy-phenyl)-quinoxalin-2-yl]-9H-carbazole (PMQC) and 9-phenyl-3,6-bis-(3-p-tolyl-quinoxalin-2-yl)-9H-carbazole (PTQC) were conveniently synthesized from the corresponding tetraone and o-phenylenediamine. Electroluminescent devices using PTQC as the dopant emitters were fabricated. These devices all emit saturated blue light from the PTQC doped layer. Device C that consists of CuPc (10 nm)/TCTA (30 nm)/PTQC:TPBI (7%, 30 nm)/TPBI (40 nm) shows the highest performance. The device emits blue light at 446 nm with CIE values of (0.15, 0.08) and shows a maximum external quantum efficiency of 1.31%, current efficiency of 1.00 cd/A, and brightness of 5067 cd/m2.