Solution-processable iridium complexes for efficient orange-red and white organic light-emitting diodes
作者:Renjie Wang、Di Liu、Run Zhang、Lijun Deng、Jiuyan Li
DOI:10.1039/c1jm13846d
日期:——
Two homoleptic and heteroleptic cyclometalated iridium complexes containing the 2-phenylbenzothiozole derivative as the main ligand, 1 and 2, have been synthesized and characterized as efficient orange-red phosphors. Triarylamine was introduced as an important substituent into the 6-position of the benzothiazole ring to tune the photonic and electronic properties of these complexes. Different from most of small molecular iridium complexes, 1 and 2 are solution-processable and their neat films can be obtained by a spin-coating method. Furthermore, their homogeneously dispersed films in a small molecular matrix, 4,4′-N,N′-dicarbazolebiphenyl (CBP), were successfully prepared by solution method even with low doping levels. Organic light-emitting diodes (OLEDs) were fabricated by solution processing the emitting layer containing 1 and 2 as doped emitters in the CBP host. Efficient orange-red electroluminescence by using 5 wt% 2 as the dopant was realized with a maximum efficiency of 14.49 cd A−1 (7.38 lm W−1 and 8.73%) and Commission Internationale de l'Eclairage (CIE) coordinates of (0.60, 0.40), which are among the highest luminance efficiency ever reported for partially solution-processed red and orange-red OLEDs so far. In addition, two-element white OLEDs were achieved with these orange-red phosphors and the traditional blue emitter by spin coating the emission layer. A maximum luminance efficiency of 8.97 cd A−1 and CIE of (0.33, 0.35) were realized.
我们合成了两种以 2-苯基苯并噻唑衍生物为主要配体的同性和异性环甲基化铱配合物 1 和 2,并将其表征为高效的橙红色荧光粉。在苯并噻唑环的 6 位引入了三芳基胺作为重要取代基,以调整这些配合物的光子和电子特性。与大多数小分子铱络合物不同的是,1 和 2 是可溶液加工的,并且可以通过旋涂法获得整洁的薄膜。此外,即使掺杂水平较低,也能通过溶液法成功制备出它们在小分子基质 4,4′-N,N′-二咔唑联苯(CBP)中均匀分散的薄膜。通过在 CBP 主基中溶液处理含有 1 和 2 作为掺杂发射体的发射层,制备出了有机发光二极管(OLED)。通过使用 5 wt% 的 2 作为掺杂剂,实现了高效的橙红色电致发光,最大效率为 14.49 cd A-1 (7.38 lm W-1 和 8.73%),国际照明委员会(CIE)坐标为 (0.60, 0.40),是迄今为止报道的部分溶液处理红色和橙红色 OLED 的最高发光效率之一。此外,利用这些橙红色荧光粉和传统的蓝色发射器,通过对发射层进行旋涂,实现了双元素白光有机发光二极管。其最大发光效率为 8.97 cd A-1,CIE 值为 (0.33, 0.35)。