New sky-blue and bluish-green emitting Ir(III) complexes containing an azoline ancillary ligand for highly efficient PhOLEDs

作者：Sarada Ganguri; Sim Bomi; Cho Woosum; Yoon Juho; Gal Yeong Soon; Kim Jang Joo; Jin Sung Ho

来源：Dyes and Pigments, 2016, 131: 60-68.

DOI：10.1016/j.dyepig.2016.03.053

• Phosphorescent organic light-emitting diode
• Iridium complex
• Rigidity
• Intersystem crossings
• Photoluminescence quantum yields
• External quantum efficiency

Two Ir(III) complexes containing the chromophoric ancillary ligands 2-(4,5-dihydrooxazol-2-yl)phenol and 2-(1-ethyl-4,5-dihydro-1H-imidazol-2-yl)phenol, and a highly functionalized phenylpyridine derivative, 3-(4-(tert-butyl)pyridin-2-yl)-2,6-difluoroberizonitrile, as a cyclometalating ligand were designed and synthesized. The oxazoline/imidazoline heterocycle of the ancillary ligand has the effect of enhancing the metal to ligand charge transfer transition nature of the emitting excited state and the fluorine and cyano substituents on the ligand have enriched the intersystem crossings, as indicated by the experimental photoluminescence analysis. As a result, the oxazoline and imidazoline containing complexes exhibited high photoluminescence quantum yields of about >90% with bright sky-blue emission at 480 nm and bluish-green light at 495 nm, respectively, along with excellent thermal/morphological stability about 400 degrees C and good solubility, that make them suitable for both wet- and dry processes. In particular, the phosphorescent OLEDs fabricated by a dry-process showed the maximum EQEs of 21.9% and 19.7% for the oxazoline and imidazoline containing complexes, respectively.

• 出版日期2016-8