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/AlQ–pNNA/Mg–Ag (ITO: indium tin oxide, NPB: N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine and AlQ is tris(8-hydroxyquinolinato)aluminium(III)). The device showed strong green emission with a narrow peak at 542 nm. When a mixture of pNNA and AlQ (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 15 000 cd m−2 was achieved at a driving voltage of 11 V.