Tao Peng, Zheng Xiao-Kang, Jiang He, Sheng Xinghao, Deng Yongjing, Chan Yuk Yin Ian, Zhao Qiang, Wong Wai-Yeung
Department of Applied Biology and Chemical Technology and Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
The Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China.
Dalton Trans. 2023 Oct 31;52(42):15496-15502. doi: 10.1039/d3dt02061d.
A pair of high-efficiency deep-red emissive ionic iridophosphors (Ira and Irb) showing high photoluminescence quantum yields (PLQYs) are rationally designed by using 1-(thiophen-2-yl)isoquinoline as the cyclometalating ligand. Two bulky tetraarylborate anions (tetraphenylborate and tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) are selected to improve their PLQYs in both solution and aggregated states, which enables efficient electroluminescence a solution-processed approach. The variation of the tetraarylborate anions also aims to tune the photophysical properties of these deep-red emissive iridophosphors. Both ionic iridophosphors emit intense deep-red room-temperature phosphorescence in both solution and aggregated states. The phosphorescence spectra of both complexes are similar (630 nm with a shoulder emission of 686 nm) in CHCl, originating from the same cationic species of the complexes. Both complexes show high PLQYs in CHCl (0.41 for Ira, 0.43 for Irb) and neat films (0.27 for Ira, 0.34 for Irb). Moreover, they serve as triplet emitters to evaluate their performance in solution-processed deep-red electroluminescent devices. The maximum external quantum efficiencies for the deep-red electroluminescence are 7.3% with an emission maximum of 649 nm for Ira, and 10.2% with an emission maximum of 635 nm for Irb, respectively, implying that they are good candidates for high-performance electroluminescence.
通过使用1-(噻吩-2-基)异喹啉作为环金属化配体，合理设计了一对具有高光致发光量子产率（PLQYs）的高效深红色发射离子型铱磷光体（Ira和Irb）。选择了两个体积较大的四芳基硼酸根阴离子（四苯基硼酸根和四(3,5-双(三氟甲基)phenyl)硼酸根）来提高它们在溶液态和聚集态中的PLQYs，这使得能够采用溶液处理方法实现高效电致发光。四芳基硼酸根阴离子的变化还旨在调节这些深红色发射铱磷光体的光物理性质。两种离子型铱磷光体在溶液态和聚集态中均发射出强烈的深红色室温磷光。两种配合物在CHCl中的磷光光谱相似（630 nm伴有686 nm的肩峰发射），源自配合物的相同阳离子物种。两种配合物在CHCl中（Ira为0.41，Irb为0.43）和纯薄膜中（Ira为0.27，Irb为0.34）均显示出高PLQYs。此外，它们作为三线态发射体来评估其在溶液处理的深红色电致发光器件中的性能。Ira的深红色电致发光的最大外量子效率为7.3%，发射最大值为649 nm，Irb的最大外量子效率为10.2%，发射最大值为635 nm，这意味着它们是高性能电致发光的良好候选材料。
