Diphenylaminoarene/Chromene-containing Red Fluorescent Emitters for Organic Light-Emitting Diodes

In this study, we synthesized new 2-(2-(4-(diphenylamino)styryl)-4H-chromen-4-ylidene) malononitrile (DCCPA) derivatives with different π-conjugation aromatic spacer groups between the diphenylamine and (chromen-4-ylidene)malononitrile moieties of the DCCPA. To explore the electroluminescence properties of these materials, multilayered OLEDs were fabricated with a device stricture of: Indium Tin Oxide (ITO) (170 nm)/N,N’-diphenyl-N,N’-(1-napthyl)-(1,1’-phenyl)-4,4’-diamine (NPB) (50 nm)/2-methyl-9,10-bis-2-naphthyl anthracene (MADN):Red dopants 1 (5, 10%) (30 nm)/bis-(2-methyl-8-quinolinolato-N1,O8)-(1,1’-biphenyl-4-olato)aluminum (Balq) (30 nm)/Liq (2 nm)/Al (10 nm). A device using Red 1 showed a maximum luminance of 1030 cd/m2 at 10.0 V, with maximum luminous, power, and quantum efficiencies of 0.94 cd/A, 0.54 lm/W, and 1.11%, respectively. The CIE coordinates of this device were (0.61, 0.35) at 7.0 V, a stable color chromaticity at various voltages.