Abstract:

In this paper, we demonstrated that controlled host-dopant concentration is essential for charge carrierstransporting in red phosphorescent organic light-emitting device (PHOLEDs). Carriers transport via (1-Phenylisoquinoline) iridium (III) dopant molecules in the emitting layer with single host, while, via both dopant and host molecules when their energy levels are well aligned. Conditions for reduction of driving voltage and enhanced efficiency of red PHOLED were obtained with mixed host structure. A pure red PHOLED with color coordinates of (0.67, 0.33) has been realized by using only 4 wt% emissive dopant, The device achieves 100 cd/cm2 at 2.9 V, with corresponding power efficiency of 9.3 lm/W and external quantum efficiency of 14.3%.

Key words: semi conductor technology, material science, red phosphorescent, mixed host, carrierstransporting