Details

Autor(en) / Beteiligte

• Lin, Ming-Shiang
• Yang, Shang-Jung
• Chang, Hong-Wei
• Huang, Yi-Hsiang
• Tsai, Yu-Tang
• Wu, Chung-Chih
• Chou, Shu-Hua
• Mondal, Ejabul
• Wong, Ken-Tsung

Titel

Incorporation of a CN group into mCP: a new bipolar host material for highly efficient blue and white electrophosphorescent devices

Ist Teil von

• Journal of materials chemistry, 2012-01, Vol.22 (31), p.16114-1612

Erscheinungsjahr

2012

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A novel bipolar host material mCPCN has been designed and synthesized by incorporating the electron-accepting CN group into the well-known benchmark host material mCP. Compared to mCP, the incorporation of the simple and small CN group significantly improves thermal/morphological stabilities ( T g = 97 °C and T d = 313 °C) and increases the electron affinity, while keeping electronic transition energies unaltered and maintaining a high triplet energy ( E T = 3.03 eV). Characteristics of single-carrier devices containing mCPCN indicate its rather balanced hole/electron injection and transport properties. Highly efficient blue phosphorescent organic light emitting devices (PhOLEDs) with maximum external quantum, current and power efficiencies of 26.4%, 58.6 cd A 1 , and 57.6 lm W 1 , respectively, were achieved using mCPCN as the bipolar host material and bis[(4,6-difluorophenyl)pyridinato- N , C 2 ]iridium( iii ) picolinate (FIrpic; E T = 2.65 eV) as the triplet emitter. Furthermore, blue PhOLEDs adopting mCPCN exhibit impressively low efficiency roll-offs, retaining high quantum efficiencies of 25% at 1000 cd m 2 and 20% even at 8000 cd m 2 . mCPCN has also been successfully used in implementing highly efficient white PhOLEDs having external quantum efficiencies in excess of 23%. A novel bipolar material mCPCN can serve as a host for highly efficient blue/white PhOLEDs, giving external quantum efficiencies of 26.4%/23.3%, and impressively low efficiency roll-offs at high brightnesses.