Novel star-shaped host materials for highly efficient solution-processed phosphorescent organic light-emitting diodes

作者：Jiang Wei; Duan Lian; Qiao Juan; Zhang Deqiang; Dong Guifang; Wang Liduo; Qiu Yong^*

来源：Journal of Materials Chemistry, 2010, 20(29): 6131-6137.

DOI：10.1039/c0jm00692k

Two novel star-shaped host materials for solution processed blue phosphorescent organic light-emitting devices, 9-(5',5'''-diphenyl[1,1': 3',1 '':3 '',1''':3''',1 ''''-quinquephenyl]-5 ''-diyl)-9H-carbazole (DQC) and 9,9'-(5'-phenyl[1,1':3',1 ''-terphenyl]-3,5-diyl)bis-9H-carbazole (PTC), were synthesized by the Suzuki coupling reaction. These compounds both exhibited high glass-transition temperatures (T(g) >= 128 degrees C) and excellent film-forming ability. The nonplanar star-shaped configuration of DQC and PTC limited the effective extension of their pi-conjugation, leading to the same triplet energy of 2.81 eV. The solution processed single layer devices using DQC and PTC as the host for the phosphorescence emitter iridium(III) bis(4,6-difluorophenylpyridinato)-picolinate (FIrpic) showed the maximum luminance efficiencies of 9.2 and 12.8 cd A(-1), respectively. By introducing a thin 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene (TPBI) electron-transporting and exciton-confining layer, the maximum efficiencies of the solution processed devices based on DQC and PTC were further improved to 21.7 and 25.7 cd A(-1) with the maximum external quantum efficiencies up to 9.2% and 11.9%, respectively. Furthermore, the DQC- and PTC-based devices showed significantly high performance compared with the corresponding devices based on 1,3-bis(9-carbazolyl)benzene (mCP).

• 出版日期2010
• 单位清华大学