Synthesis and Characterization of Oxadiazole-Containing Molecules with High Band Gap, and Application in Blue Phosphorescent Organic Light Emitting Diodes

In this thesis, we synthesized a series of bipolar oxadiazole derivatives as the host materials for blue phosphorescent organic light emitting diodes. Taking 2,5-diphenyl-1,3,4-oxadiazole (DPO) as our basic structure, we introduced aromatic ring which has more rigid characteristic to increase molecular weight for improving the thermal stability of oxadiazole derivatives. Meanwhile, we used methyl groups to twist biphenyl structure in order to shorten the conjugation length of molecules. By using thermal analysis, spectroscopy and electrochemical method, we could observe their thermal, photophysical and electrochemical properties. In the end, we fabricated the phosphorescent organic light emitting diode incorporating compound 4 as the host matrix doped with the blue-light triplet guest emitter bis(4,6-difluorophenylpyridinato-N,C2)picolinatoiridium (FIrpic). The device exhibited luminance efficiency of 11.7cd/A at 372 cd/m2, and the maximum brightness of 1472 cd/m2.