Zhang Lin, Yan Zhi-Ping, Zheng You-Xuan
State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China.
Dalton Trans. 2019 Jul 2;48(26):9744-9750. doi: 10.1039/c9dt00298g.
The lack of efficient blue-emitting materials is one of the most important issues faced when extending the application of organic light-emitting diodes (OLEDs). Therefore, in this study, the ancillary ligand bis(diphenylphorothioyl)amide (Stpip) was utilized in iridium(iii) complexes with 2-(2,4-difluorophenyl)pyridine (dfppy) and 2-(2,4-difluorophenyl)pyrimidine (dfppm) as the main ligands, respectively. The two complexes, (dfppy)2Ir(Stpip) and (dfppm)2Ir(Stpip), exhibit sky-blue emission peaks at 466 and 474 nm with photoluminescence quantum yields of 12% and 89%, respectively. Due to the strong coordination capability between sulfur and iridium atoms, both complexes can be prepared with extremely high production yields under mild conditions. Furthermore, a double light-emitting layer device using (dfppm)2Ir(Stpip) as the emitter exhibits a maximum external quantum efficiency (EQEmax) of 19.4% with Commission Internationale de l'Eclairage (CIE) coordinates of (0.13, 0.27). Specifically, the EQE remains at 19.2% at a practical brightness of 1000 cd m-2, indicating an inappreciable efficiency roll-off.
缺乏高效的蓝色发光材料是扩展有机发光二极管（OLED）应用时面临的最重要问题之一。因此，在本研究中，辅助配体双（二苯基磷酰基）酰胺（Stpip）分别用于以2-（2,4-二氟苯基）吡啶（dfppy）和2-（2,4-二氟苯基）嘧啶（dfppm）为主要配体的铱（III）配合物中。两种配合物，（dfppy）2Ir（Stpip）和（dfppm）2Ir（Stpip），分别在466和474 nm处呈现天蓝色发射峰，光致发光量子产率分别为12%和89%。由于硫和铱原子之间强大的配位能力，两种配合物都可以在温和条件下以极高的产率制备。此外，使用（dfppm）2Ir（Stpip）作为发光体的双发光层器件表现出19.4%的最大外量子效率（EQEmax），国际照明委员会（CIE）坐标为（0.13, 0.27）。具体而言，在实际亮度为1000 cd m-2时，外量子效率保持在19.2%，表明效率滚降不明显。
