Efficient green electroluminescence of pure chromaticity from a polycyclic aromatic hydrocarbon

A new highly fluorescent material with a condensed aromatic ring, 7-naphthylbenzo[a]perylene (pNNA), was synthesized for application in organic electroluminescent devices (OELDs). The fluorescent quantum yield of this material in a 1 × 10^-5 M solution of dichloromethane approached unity. OELDs have been fabricated with a configuration of ITO/NPB/AIQ-pNNA/Mg-Ag (ITO: indium tin oxide, NPB: N,N′-bis(1-naphthyl)-N,N′diphenyl-1,1′-biphenyl-4, 4′-diamine and AIQ is tris(8-hydroxyquinolinato)aluminium(111)). The device showed strong green emission with a narrow peak at 542 nm. When a mixture of pNNA and A1Q (1:400) was deposited from a single source, the electroluminescent efficiency of the devices reached 6.5 cd A^-1 at 20 mA cm^-2 and 7.8 V. A brightness of 15000 cd m^-2 was achieved at a driving voltage of 11 V.