A novel n-type red luminescent material for organic light-emitting diodes

A novel red luminescent material N,N-bis{4-[2-(4-dicyanomethylene-6-methyl-4H-pyran-2-yl)ethylene]phenyl}aniline (BDCM) with two (4-dicyanomethylene)-4H-pyran electron-acceptor moieties and a triphenylamine electron-donor moiety for application in organic light-emitting diodes (OLEDs) was synthesized. The resultant compound has a sterically well-hindered structure and a high fluorescence yield. The photoluminescence (PL) of this compound in solution and solid film and the electroluminescence (EL) have been studied. Based on its intense sterically hindered structure, the pure BDCM film prepared shows a bright red PL emission. The three-layered EL device with the structure ITO/CuPc/DPPhP/BDCM/Mg:Ag has a turn-on voltage of less than 4 V, which suggests that BDCM has an excellent electron injection property. A bright luminance of 582 cd m(-2) is obtained for the device at 19 V.