Novel bis- and tris-cyclometalated iridium(III) complexes bearing a benzoyl group on each fluorinated 2-phenylpyridinate ligand aimed at development of blue phosphorescent materials for OLED
Novel bis- and tris-cyclometalated iridium(III) complexes bearing a benzoyl group on each fluorinated 2-phenylpyridinate ligand aimed at development of blue phosphorescent materials for OLED
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DOI：
10.1039/c6ra09385j
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发表时间：
2016-05
期刊：
影响因子：
3.9
通讯作者：
Naoki Okamura;Taiyo Nakamura;S. Yagi;Takeshi Maeda;H. Nakazumi;H. Fujiwara;S. Koseki
中科院分区：
文献类型：
--
作者：
Naoki Okamura;Taiyo Nakamura;S. Yagi;Takeshi Maeda;H. Nakazumi;H. Fujiwara;S. Koseki
为了开发用于有机发光二极管（OLED）的蓝色磷光材料，开发了在氟化2-苯基吡啶配体上带有苯甲酰基的新型双环和三环合铱（III）配合物。以乙酰丙酮（acac）为辅助配体，氟取代基使5′-苯甲酰化双环取代配合物的发射波长蓝移至479 nm（室温二氯甲烷中，发射蓝绿色光）。2-（5-苯甲酰基-4，6-二氟苯基）吡啶基双环取代配合物中的辅助配体从acac置换为吡啶甲酸酯，导致λPL进一步蓝移至464 nm，观察到天蓝色发射。2-（5-苯甲酰基-4，6-二氟苯基）吡啶基均配型三环化配合物在463 nm处的λPL比本文开发的任何其他二环化和三环化配合物显示出更多的蓝移，发射天蓝色，光致发光量子产率为0.90（在二氯甲烷中，室温）。使用该天蓝色磷光三环化配合物作为发光掺杂剂，制备了基于聚（9-乙烯基咔唑）的OLED，并且观察到具有（0.16，0.28）的国际照明委员会（Commission Internationale de L 'eclairage，CIE）色坐标的优异的蓝色发光，其中获得了1.81%的外量子效率（ηext）。通过使用溶液处理的双发光层器件结构，OLED性能显著改善，并且对于本发明的天蓝色磷光双环和三环化铱（III）配合物，分别实现8.55和7.46%的ηexts（CIE色度坐标：分别为（0.17，0.33）和（0.17，0.29））。
Novel bis- and tris-cyclometalated iridium(III) complexes bearing a benzoyl group on each fluorinated 2-phenylpyridinate ligand were developed, aimed at the development of blue phosphorescent materials for organic light-emitting diodes (OLED). When acetylacetonate (acac) was employed as an ancillary ligand, the emission wavelength (λPL) of the 5′-benzoylated bis-cyclometalated complex was blue-shifted up to 479 nm (in dichloromethane at rt, emitting bluish green) in combination with fluorine substituents. Ancillary ligand replacement in the 2-(5-benzoyl-4,6-difluorophenyl)pyridinate-based bis-cyclometalated complex from acac to picolinate gave rise to a further blue shift of λPL to 464 nm, and sky-blue emission was observed. The 2-(5-benzoyl-4,6-difluorophenyl)pyridinate-based homoleptic tris-cyclometalated complex exhibited a more blue-shifted λPL at 463 nm than any other bis- and tris-cyclometalated complexes developed here, emitting sky blue with a photoluminescence quantum yield of 0.90 (in dichloromethane at rt). Using this sky-blue phosphorescent tris-cyclometalated complex as an emitting dopant, a poly(9-vinylcarbazole)-based OLED was fabricated, and excellent blue emission with a Commission Internationale de L'eclairage (CIE) chromaticity coordinate of (0.16, 0.28) was observed, where an external quantum efficiency (ηext) of 1.81% was obtained. The OLED performance was drastically improved by using a solution-processed double-emitting layer device structure, and ηexts of 8.55 and 7.46% were achieved for the present sky-blue phosphorescent bis- and tris-cyclometalated iridium(III) complexes, respectively (CIE chromaticity coordinates: (0.17, 0.33) and (0.17, 0.29), respectively).