New efficient fused-ring spiro[benzoanthracene-fluorene] dopant materials for blue fluorescent organic light-emitting diodes

New blue fluorescent spirobenzoanthracene-type dopant materials, 3,9-di(di( p -tolyl))aminospiro[benzo[ de ]anthracene-7,9′-fluorene] ( DTSBAF ) and 3,9-di(di(4-biphenyl))aminospiro[benzo[ de ]anthracene-7,9′-fluorene] ( DBSBAF ), were designed and successfully prepared by an amination reaction of 3-bromo-9-chlorospiro[benzo[ de ] anthracene-7,9′-fluorene] with di( p -tolyl)amine and di(4-biphenyl)amine, respectively. The EL characteristics of 1,10-dinaphthylspiro[benzo[ ij ]tetraphene-7,9′-fluorene] ( DNSBTF ) as the blue host material doped with the above blue dopant materials was evaluated. The electroluminescence spectra of indium tin oxide (150 nm)/ N , N ′-diphenyl- N , N ′-bis[4-(phenyl- m -tolyl-amino)phenyl]-biphenyl-4,4′-diamine (DNTPD, 60 nm)/ N , N , N ′, N ′-tetra(1-biphenyl)-biphenyl-4,4′-diamine (TBB, 30 nm)/ SBTF hosts: SBAF dopant (20 nm, 5%)/9,10-di(naphthalene-2-yl)anthracen-2-yl-(4,1-phenylene)(1-phenyl-1 H -benzo[ d ]imidazole) (LG201, 20 nm)/LiF (1 nm)/Al (200 nm) with DNSBTF as a host material show a blue emission band with a full width at half maximum of 50 nm and λ max = 472 nm. The device obtained from DNSBTF doped with DTSBAF showed a good color purity (0.141, 0.254), high luminance efficiency (10.12 cd A −1 at 5 V) and high external quantum efficiency (6.02%).