We report on a series of blue and deep-blue emitting zwitterionic iridium(III) complexes, consisting formally of a cationic Ir centre and a N,N′-heteroaromatic (N^N) ligand bearing negatively charged side groups, i.e. sulfonate and borate. The synthesis, photophysical and electrochemical properties of this series are described in detail together with their X-ray crystal structure determination. The reported complexes exhibit intense blue (λmax at 450 nm) and deep blue (λmax at 435 nm) emission in deaerated solution, similar to the related cationic complexes. The strategy employed, namely the internal salt formation, allows high solubility in many organic solvents as well as for some of the complexes a low sublimation temperature. For this reason, one of the complexes was further tested as an emitter in phosphorescent organic light emitting diodes (PhOLEDs). Despite the zwitterionic nature of the triplet emitter employed, the devices were fabricated by means of sublimation process. The devices showed a peak external quantum efficiency (EQE) as high as 11.0% and Commission Internationale d'Énclairage (CIE) coordinates x = 0.21 and y = 0.33.
我们报告了一系列发出蓝色和深蓝色的两性離子
铱(III)复合物,这些复合物形式上由一个阳离子
铱中心和一个带有负电荷侧基的N,N′-杂芳香族(N^N)
配体组成,即
磺酸盐和
硼酸盐。我们详细描述了这一系列的合成、光物理和电
化学特性,以及它们的X射线晶体结构测定。所报道的复合物在去气溶液中表现出强烈的蓝色(λmax在450 nm)和深蓝色(λmax在435 nm)发射,类似于相关的阳离子复合物。采用的策略,即内部盐的形成,使得在许多有机溶剂中具有高溶解度,同时一些复合物具有低升华温度。因此,其中一个复合物进一步作为发射体在
磷光有机发光二极管(PhOLEDs)中进行了测试。尽管所用的三重态发射体具有两性离子特性,但设备是通过升华过程制造的。该设备显示出高达11.0%的峰值外量子效率(EQE)和国际照明委员会(CIE)坐标x = 0.21和y = 0.33。