Blue organic electroluminescent devices based on the spiro[fluorene-7,9′-benzofluorene] derivatives as host and dopant materials

The novel spiro[fluorene-7,9′-benzofluorene]-based blue host material, 2-(10-phenylanthracene)-spiro[fluorene-7,9′-benzofluorene] (BH-3P), was successfully prepared by reacting 2-bromo-9,11-spiro[benzofluorene-fluorene] (3) with 9-phenylanthracene-10-boronic acid through the Suzuki reaction. Diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]-amine (BD-1), 2-[4′-(phenyl-4-vinylbenzeneamine)phenyl-spiro[fluorene-7,9′-benzofluorene] (BH-3BD) and 4-[2-naphthyl-4′ (phenyl-4-vinylbenzeneamine)]phenyl (BD-1N) were used as dopant materials. Blue OLEDs with the configuration of ITO/DNTPD/α-NPD/BH-3P:5% dopant/Alq3/Al–LiF were prepared from the BH-3P host and BD-1, BD-1N and BH-3BD dopants and they showed blue EL spectra at around 452 nm at 7 V and luminance efficiencies of 1.9–3.3 cd/A.