| 초록 |
A series of modified bis(4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl)dimethylsilane (ST), ST-CF3, ST-Me, ST- tBu, and ST-OMe, were designed and prepared by introducing the electron-withdrawing groups or the electron-donating groups at the 4-position of the end-on phenyl groups on the triazole ring. Systematic investigations of their thermal-, photophysical-, and electron-transporting properties were successfully carried out. Depending on the electronic characteristics of the substituents at the end-phenyl group on the triazole, their frontier orbital energy levels were controlled while maintaining energy band gaps. Low- temperature photoluminiscenec spectra indicate that all the prepared ST moieties maintained high triplet energy states up to 2.85 eV owing to the suppression of electron delocalization by silicon centre. Finally, the EL device utilizing ST-tBu as an electron transporting material in PhOLED with FIrpic as a dopant showed an external quantum efficiency of 15% |
