Organic Light-Emitting Devices Consisting of N-Triarylamine-Based Hole Injecting/Transporting Materials

Abstract

A series of N-triarylamine-based derivatives such as 4,4'-bis[N-(1- naphthyl)-N-phenyl-amino]biphenyl (-NPD), 1,3,5-tris[4-(3-methylphenyl(phenyl) amino)phenyl]benzene (m-MTDAPB) and 1,3,5-tris-{4-[1-naphthyl(phenyl)amino] phenyl}benzene (1-TNAPB) were synthesized and characterized. Specially, 1-TNAPB was synthesized with high yield in 1hr. The hole injecting/transporting properties of these materials were investigated by using double-layered organic light-emitting diodes (OLEDs) with the configuration of ITO/N-triarylamine/Alq3/ LiF/Al, in which Alq3 was used as an emitting and electron transporting layer. A comparative study on EL performance of OLEDs fabricated with N-triarylamines as the hole injecting/transporting layer revealed that better results were observed in OLED with m-MTDAPB and -NPD, respectively. OLED with m-MTDAPB (20nm thickness) showed maximum luminescence of 15,970cd/m2 at 10V and turn-on voltage of 4V. On the other hand, -NPD (50nm thickness) exhibited maximum luminescence of 17,650cd/m2 at 17V and turn-on voltage of 7V.