| 초록 |
A series of four triazol-containing compounds for the type of dimethylbis(4-(4-phenyl-5-(4-(X)phenyl)-4H-1,2,4-triazol-3-yl)phenyl)silane (ST) derivative have been tested as electron-transport material for deep blue phosphorescent OLEDs. A systematic change in the electronic structures is achieved in these compounds by incorporating electron-withdrawing (EW) and –donating (ED) groups (X = –CF3, –Me, –tBu, and –OMe) at the 4-position of the phenyltriazole group. From their electrochemical properties obtained from cyclic voltammetric measurement, we observed that the LUMO level was significantly affected by different substituents. Overally, all prepared compounds have relatively high triplet energy levels, which is compatible with the energy level of blue phosphorescent emitting layer in blue OLED device. TDDFT calculations were also performed to figure out their frontier orbital distributions and their transition states. Using current-voltage (I-V) and IS measurement of electron only devices (EOD) and OLED, we have obtained values for the Richardson factor, the barrier height, trap density, density of states (DOS) and carrier mobility of ST derivatives and interfaces as device parameters. |
