New asymmetric monostyrylamine dopants for blue light-emitting organic electroluminescence device

Four new dopant materials containing a monostyrylamine moiety, 4-(1,2-diphenylvinyl)-4′-(N,N-diphenylamino)biphenyl (TP-BP), 4-(1,2-diphenylvinyl)-4′-(N,N-ditolylamino)biphenyl (TP-MP), 4-(1,2-diphenylvinyl)-4′-(N-naphthyl-N-phenylamino)biphenyl (TP-NP) and 4-[1-phenyl-2-(4-biphenyl)vinyl]-4′-(N,N-diphenylamino)biphenyl (TP-BiP) were synthesized by the Wittig–Horner reaction, followed by an amination reaction with various aromatic diamines. Blue OLEDs were obtained from the distyrylarylene host materials TPM-BP, TPM-MP and TPM-BiP. The structure of the device is an ITO/DNTPD/NPB/TPM host, TP dopant/Alq3/Al–LiF. Here, NPB is used as the hole transport layer, DNTPD as the hole injection layer, the TPM series host as the blue emitting host, TP series as dopant, Alq3 as the electron transport layer, and Al as the cathode. Their photophysical and electroluminescent properties, including efficiency, current density, and CIE coordinates were examined.