Fast Synthesis of Iridium(III) Complexes Incorporating a Bis(diphenylphorothioyl)amide Ligand for Efficient Pure Green OLEDs

Bis­(diphenylphorothioyl)­amide (Stpip) containing phosphor–sulfur (PS) bonds was used as an ancillary ligand for three pure green iridium­(III) emitters Ir1, Ir2, and Ir3, which were synthesized in few minutes at room temperature with high reaction yields above 70%. All these complexes show good thermal stability and excellent sublimation yields of around 80–90%, which are considered beneficial for industry practical production and organic light-emitting diode (OLED) fabrication. The emission profiles of these complexes meet the green standards of CIE1931 with coordinates of (0.33, 0.63), (0.33, 0.62), and (0.34, 0.62), respectively, and high photoluminescence quantum yields of up to 98% are achieved. Utilizing these complexes as emissive dopants, these OLEDs exhibited high current efficiency up to 91.94 cd A–1, external quantum efficiency up to 26.52%, and power efficiency up to 92.60 lm W–1 with very small efficiency roll-off, without adopting internal or external out-coupling methods. These results indicate that Stpip is a potentially suitable ligand scaffold for highly efficient phosphorescent Ir­(III) emitters that endow corresponding OLEDs with high efficiency and small roll-off.

双(二苯基硫代磷酰)胺（Stpip）含有磷-硫（P=S）键，被用作三种纯绿色铱(III)发光材料Ir1、Ir2与Ir3的辅助配体。该类配合物可在室温条件下数分钟内完成合成，反应产率均高于70%。所有配合物均具备良好的热稳定性与约80%~90%的优异升华产率，这一特性有利于工业化实际生产与有机发光二极管（Organic Light-Emitting Diode, OLED）的制备。上述配合物的发射光谱符合CIE1931绿色标准，色坐标分别为(0.33, 0.63)、(0.33, 0.62)与(0.34, 0.62)，且光致发光量子产率最高可达98%。以这些配合物作为发光掺杂剂制备的OLED器件，展现出高达91.94 cd·A⁻¹的电流效率、26.52%的外量子效率以及92.60 lm·W⁻¹的功率效率，且效率滚降极小，未采用任何内外光提取方法。研究结果表明，Stpip是一种极具应用潜力的配体骨架，可用于制备高效磷光铱(III)发光材料，使对应的OLED器件兼具高发光效率与极小的效率滚降特性。