| 초록 |
In this study, dibenzothiophene based host materials were synthesized by connecting carbazole via different substitution positions of the carbazole moieties on 2-, 8- position of dibenzothiophene. These three materials, 2,8-bis(9-phenyl-9H-carbazol-1-yl)dibenzo[b,d]thiophene (1Cz-DBT), 2,8-bis(9-phenyl-9H-carbazol-3-yl)dibenzo[b,d]thiophene (3Cz-DBT) and 2,8-bis(9-phenyl-9H-carbazol-4-yl)dibenzo[b,d]thiophene (4Cz-DBT) have a high triplet energy (≥ 2.61 eV) and thermal stability. The 1Cz-DBT host material has shallow the energy level which can be matched with that of blue phosphorescent material, tris[1-(2,4-diisopropyldibenzo[b,d]furan-3-yl)-2-phenylimidazole] (Ir(dbi)3). Therefore, maximum quantum efficiency of the 1Cz-DBT device was 25.4 % and maximum power efficiency was 59.2 lm/W. The color coordinates of the 1Cz-DBT, 3Cz-DBT and 4Cz-DBT devices were (0.19, 0.39), (0.19, 0.40) and (0.19, 0.39), respectively. Additionally, the operational lifetime of 1Cz-DBT, 3Cz-DBT and 4Cz-DBT devices were observed as 50 h, 303 h and 133 h at 1,000 cd/m2, respectively. |
