A Synthesis and Luminescence Study of Ir(ppz)3 for Organic Light-Emitting Devices

Abstract

Abstract Tris(1-phenyl-κC1-pyrazolato-κN2)iridium (Ir(ppz)3) was prepared and its luminescence properties were investigated for the application to organic light-emitting devices (OLEDs). The photoluminescence (PL) spectra of Ir(ppz)3 in dichloromethane showed a peak at 437 nm at room temperature. The luminescent lifetime of an Ir(ppz)3 film doped in CBP was found to be 218 ns, which indicated that its emission is phosphorescent. OLEDs were fabricated with doped films of Ir(ppz)3 in several hosts, and the electroluminescence (EL) peak was observed at 450 nm. The luminance of OLEDs was pure blue, with the CIE coordinates of x = 0.158, y = 0.139 at 100 cd/m2, but luminous efficiencies were low since the LUMO of Ir(ppz)3 is higher than those of the hosts used.