Fabrication of Phosphorescence WOLEDs Based on Dimeric Phenoxazine Derivative for Hole Injection Layer

Hole injection material, namely, 10,10.-bis(4-tert-butylpheny1)-N7,N7'-di(naphthalen-1-yl)-N7,N7'dipheny1-10H,10'H-3,3'-biphenoxazine-7,7'-diamine (1-PNA-BPBPDX), were adapted to white OLED devices for solution process. White devices were fabricated using a multilayer emission structure, consisting of a single host layer. The red phosphorescent, (Ir(piq)(3)), and the blue phosphorescent, (Flrpic), are doped into separate layers of (mCP) host. The Flrpic and Ir(piq)(3) guest molecules are directly excited by direct recombination on these molecules. When the device with BPBPDX was compared to the device with PEDOT:PSS, a commercialized solution HIL material, the luminance efficiency was 6.37 cd/A for BPBPDX and 0.66 cd/A for PEDOT:PSS for the optimized white device structure, showing 10 times as high efficiency.