Zhu Jianing, Huang Manli, Zhang Youming, Chen Zhanxiang, Deng Yijia, Zhang Hongyang, Wang Xinzhong, Yang Chuluo
Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, P. R. China.
College of Physical and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, P. R. China.
Angew Chem Int Ed Engl. 2025 Feb 3;64(6):e202418770. doi: 10.1002/anie.202418770. Epub 2024 Dec 10.
Among the various challenges in the field of organic light-emitting diodes (OLEDs), simultaneously achieving high efficiency, a long lifespan, and a narrow full-width at half maximum (FWHM) in blue OLEDs remains a significant hurdle. Herein, we demonstrate a strategy to improve the color purity of tetradentate Pt(II) complexes with the assistance of ⋅⋅⋅H interaction by incorporating trifluoromethyl (-CF) groups into the well-known blue tetradentate Pt(II) phosphorescent complex. The results show that the different substitution positions of -CF have significantly varying effects on the FWHM values of the complexes; specifically, introducing -CF on the benzene ring of carbazole effectively reduces the FWHM, while introducing it on the benzene ring linked to the carbene unit has a minimal impact. When utilized in a mixed host system of SiCzCz/SiTrzCz2, the OLEDs with these new complexes as emitters demonstrated maximum external quantum efficiencies (EQEs) of 27.1 %, 33.8 %, and 27.6 % for PtON-CF-1, PtON-CF-2, and PtON-2CF, respectively, with excellent color purity (CIEy≈0.14 for the PtON-CF-2 based device). Notably, the device based on PtON-CF-2 matched the stability of the benchmark PtON-TBBI complex.This work offers an important guideline for the design of high efficient Pt(II) phosphorescent complexes with good blue color purity.
在有机发光二极管（OLED）领域的各种挑战中，在蓝色OLED中同时实现高效率、长寿命和窄半高宽（FWHM）仍然是一个重大障碍。在此，我们展示了一种策略，通过将三氟甲基（-CF）基团引入著名的蓝色四齿Pt（II）磷光配合物中，借助⋅⋅⋅H相互作用来提高四齿Pt（II）配合物的色纯度。结果表明，-CF的不同取代位置对配合物的FWHM值有显著不同的影响；具体而言，在咔唑的苯环上引入-CF可有效降低FWHM，而在与卡宾单元相连的苯环上引入则影响最小。当在SiCzCz/SiTrzCz2混合主体系统中使用时，以这些新配合物作为发光体的OLED对于PtON-CF-1、PtON-CF-2和PtON-2CF分别表现出27.1%、33.8%和27.6%的最大外量子效率（EQE），具有出色的色纯度（基于PtON-CF-2的器件CIEy≈0.14）。值得注意的是，基于PtON-CF-2的器件与基准PtON-TBBI配合物的稳定性相当。这项工作为设计具有良好蓝色色纯度的高效Pt（II）磷光配合物提供了重要指导。
