TY - JOUR
T1 - Tuning charge balance in solution-processable bipolar triphenylamine-diazafluorene host materials for phosphorescent devices
AU - Fan, Zhaokang
AU - Zhao, Huiru
AU - Li, Nengquan
AU - Quan, Yiwu
AU - Chen, Qingmin
AU - Ye, Shanghui
AU - Li, Shuhua
AU - Wang, Ying
AU - Fan, Quli
AU - Huang, Wei
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/5/13
Y1 - 2015/5/13
N2 - Three bipolar hosts, namely TPA-DAF, TPA-DAF2, and TPA-DAF3, comprising an electron-donating triphenylamine (TPA) group and electron-accepting 4,5-diazafluorene (DAF) units are investigated for phosphorescent organic light-emitting diodes (PhOLEDs). Given the nonplanar structure of the sp3-hybridized C9 atom in DAF unit, these molecules have a highly nonplanar configuration, good film-forming property, and high triplet energy (ET) of 2.88-2.89 eV. Among them, TPA-DAF shows more balanced carrier injecting/transporting ability, suitable highest occupied molecular orbital (MO) energy level and higher current density, and therefore TPA-DAF-based devices exhibit the best performances, having an extremely slight efficiency roll-off with current efficiency of 20.0 cd/A at 973 cd/m2, 19.5 cd/A at 5586 cd/m2, and 17.6 cd/A at 9310 cd/m2 for blue PhOLEDs; 23.5 cd/A at 1059 cd/m2 and 15.3 cd/A at 8850 cd/m2 for green PhOLEDs; and 12.2 cd/A at 1526 cd/m2, 10.5 cd/A at 5995 cd/m2, and 9.2 cd/A at 8882 cd/m2 for red PhOLEDs, respectively. The results also provide a direct proof for the influence of charge balance on the device performance.
AB - Three bipolar hosts, namely TPA-DAF, TPA-DAF2, and TPA-DAF3, comprising an electron-donating triphenylamine (TPA) group and electron-accepting 4,5-diazafluorene (DAF) units are investigated for phosphorescent organic light-emitting diodes (PhOLEDs). Given the nonplanar structure of the sp3-hybridized C9 atom in DAF unit, these molecules have a highly nonplanar configuration, good film-forming property, and high triplet energy (ET) of 2.88-2.89 eV. Among them, TPA-DAF shows more balanced carrier injecting/transporting ability, suitable highest occupied molecular orbital (MO) energy level and higher current density, and therefore TPA-DAF-based devices exhibit the best performances, having an extremely slight efficiency roll-off with current efficiency of 20.0 cd/A at 973 cd/m2, 19.5 cd/A at 5586 cd/m2, and 17.6 cd/A at 9310 cd/m2 for blue PhOLEDs; 23.5 cd/A at 1059 cd/m2 and 15.3 cd/A at 8850 cd/m2 for green PhOLEDs; and 12.2 cd/A at 1526 cd/m2, 10.5 cd/A at 5995 cd/m2, and 9.2 cd/A at 8882 cd/m2 for red PhOLEDs, respectively. The results also provide a direct proof for the influence of charge balance on the device performance.
KW - 4,5-diazafluorene
KW - bipolar host
KW - phosphorescent diodes
KW - triphenylamine
UR - http://www.scopus.com/inward/record.url?scp=84929192104&partnerID=8YFLogxK
U2 - 10.1021/am509014v
DO - 10.1021/am509014v
M3 - 文章
AN - SCOPUS:84929192104
SN - 1944-8244
VL - 7
SP - 9445
EP - 9452
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 18
ER -