Distinct phosphorescence enhancement of red-emitting iridium(III) complexes with formyl-functionalized phenylpyridine ligands
Distinct phosphorescence enhancement of red-emitting iridium(III) complexes with formyl-functionalized phenylpyridine ligands
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具有甲酰基官能化苯基吡啶配体的发红光铱 (III) 配合物的明显磷光增强
DOI：
10.1039/c6tc00856a
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发表时间：
2016-01-01
影响因子：
6.4
通讯作者：
Huang, Wei
中科院分区：
文献类型：
--
作者：
Cao, Sizhen;Hao, Lin;Huang, Wei
合成了一种新的高效发红光Ir（III）配合物，双[9-（4-（2-乙基己氧基）苯基）-3-（4-苯基喹啉-2-基）- 9h -咔唑][3-（吡啶-2-基）苯甲醛]铱（III） （Ir- cho），并对其进行了表征，研究了吸电子酰基对Ir（III）配合物光电性能的影响。为了比较，还制备了双[9-（4-（2-乙基己氧基）苯基）-3-（4-苯基喹啉-2-基）- 9h -咔唑][（3-（吡啶-2-基）苯基）甲醇]铱（III） （Ir-OH）和双[9-（4-（2-乙基己氧基）苯基）-3-（4-苯基喹啉-2-基）- 9h -咔唑]铱（III） （Ir-PQCz）。值得注意的是，ir - co掺杂的红色有机发光二极管（oled）表现出最高的性能，最大发光效率（LE）为14.3 cd a−1，外量子效率（EQE）为8.4%，优于ir - oh掺杂和ir - pqcz掺杂的红色有机发光二极管。这一结果可归因于引入了吸电子的甲酰基，提高了Ir-CHO的电子亲和力，降低了Ir-CHO基oled的电子注入势垒。同样，以Ir-CHO为红色发射体的白色oled （WOLEDs）显示出26.1 cd A−1的高LE和10.9%的EQE。结合这些Ir（III）配合物的热学、光物理、电化学和电致发光（EL）性质可以得出结论，即加入吸电子的甲酰基取代苯吡啶（py- cho）可以明显改善所得到的发红光铱配合物的磷光，从而提高OLED性能。该结果为合理设计用于发光应用的高效磷光配合物提供了一种简单的方法。
A new highly efficient red-emitting Ir(III) complex, bis [9-(4-(2-ethylhexyloxy)phenyl)-3-(4-phenylquinolin-2-yl)-9H-carbazole] [3-(pyridin-2-yl) benzaldehyde]iridium(III) (Ir-CHO), has been synthesized and characterized to investigate the impact of the electron-withdrawing formyl group on the optoelectronic properties of the resulting Ir(III) complexes. For comparison, bis [9-(4-(2-ethylhexyloxy)phenyl)-3-(4-phenylquinolin-2-yl)-9H-carbazole] [(3-(pyridin-2-yl) phenyl) methanol] iridium(III) (Ir-OH) and fac-tris[9-(4-(2-ethylhexyloxy)phenyl)-3-(4-phenylquinolin-2-yl)-9H-carbazole] iridium(III) (Ir-PQCz) were also prepared. Remarkably, Ir-CHO-doped red organic light-emitting diodes (OLEDs) exhibited the highest performance, achieving a maximum luminance efficiency (LE) of 14.3 cd A−1 and an external quantum efficiency (EQE) of 8.4%, which were better than those of Ir-OH-doped and Ir-PQCz-doped red OLEDs. The results can be attributed to the introduction of the electron-withdrawing formyl group, which improved the electron affinity in Ir-CHO and lowered the electron-injection barrier in OLEDs based on Ir-CHO. Similarly, white OLEDs (WOLEDs) with Ir-CHO as their red emitter demonstrated an excellent high LE of 26.1 cd A−1 and an EQE of 10.9%. A combination of the thermal, photophysical, electrochemical and electroluminescence (EL) properties of these Ir(III) complexes can thus lead to a conclusion that the incorporation of the electron-withdrawing formyl-substituted phenylpyridine (ppy-CHO) can apparently improve the phosphorescence of the resulting red-emitting iridium complexes and thus the OLED performance. The results suggest a simple methodology for the rational design of efficient phosphorescent complexes for light-emitting applications.