The unusual electrochemical and photophysical behavior of 2,2 '-bis(1,3,4-oxadiazol-2-yl)biphenyls, effective electron transport hosts for phosphorescent organic light emitting diodes

摘要

The fluorescence and phosphorescence of 2,2'-bis(5-phenyl-1,3,4-oxadiazol-2-yl)biphenyl shows good spectral matching with the absorption spectra of the MLCT1 and MLCT3 transitions of Ir(ppy)(3). The red-shift of the 0-0 band in the phosphorescence at 77 K is due to the intramolecular pi-pi interactions between the oxadiazole side chains. Maximum brightness of 43 000 cd/m(2) with an efficiency of 26 cd/A at 200 cd/m(2) was achieved when BOBP was used as the host material for Ir(ppy)(3) in the PHOLED study.