Deep blue fluorescent host materials based on a novel spiro[benzo[C] fluorene-7,9'-fluorene] core structure with side aromatic wings

Abstract

Deep blue fluorescent host materials based on a novel spiro[benzo[c] fluorene-7,9'-fluorene] core structure with side aromatic wings in the 5- and 9-positions, namely, 5,9-di(naphthalen-2-yl)spiro[benzo[c]fluorene-7,9'- fluorene] (DN-SBFF), 5,9-bis(4-t-butylphenyl)spiro[benzo[c]fluorene-7,9'- fluorene] (BP-SBFF), and 5,9- bis(4-fluorophenyl)spiro[benzo[c]fluorene-7,9'- fluorene] (FP-SBFF), were designed and successfully prepared using the Suzuki reaction. The physical properties of these materials and their EL characteristics as blue host materials doped with N,N,N',N'- tetraphenylspiro[benzo[c]fluorene-7,9'-fluorene]-5,9-diamine (TPA-SBFF) were investigated. The device used comprised ITO/N,N'-diphenyl-N,N'-bis[4-(phenyl-m- tolyl-amino)phenyl]- biphenyl-4,4'-diamine (DNTPD)/N,N'-di(1-naphthyl)-N,N'- diphenylbenzidine (NPB)/(FP-SBFF):dopant x%/ tris(8-hydroxyquinoline)aluminum (Alq3)/LiF. The device obtained using FP-SBFF doped with TPA-SBFF showed high color purity (0.13, 0.18) and an efficiency of 6.61 cd/A at 7 V.