Red electrophosporescence from oxadiazoles-functionalized iridium complexes in polymer light-emitting devices

A type of oxadiazole-functionalized iridium complex is newly employed as red phosphor emmiter in polymer light-emmiting devices (PLEDs) using a blend of poly (9,9-dioctylflourene)(PFO) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD) as a host matrix. The devices show bright red electrophosphoresence with dominant peaks at about 593nm and shoulders at about 642nm. The highest luminance efficiency of 3.3 cd/A at 9.3 V and maximum luminance of 2912 cd/m(2) at 14.0 V are achieved in the devices. At current density of 100 mA/cm(2), the devices still exhibit luminance efficiency of 2.2 cd/A and luminance of 2300 cd/m(2). This indicates that the oxadiazole-functionalized iridium complexes have improved optoelectronic properties in the devices at high current density.