Confining isolated chromophores for highly efficient blue phosphorescence

• Published in: Nature materials Vol. 20; no. 11; pp. 1539 - 1544
• Main Authors: Ye, Wenpeng, Ma, Huili, Shi, Huifang, Wang, He, Lv, Anqi, Bian, Lifang, Zhang, Meng, Ma, Chaoqun, Ling, Kun, Gu, Mingxing, Mao, Yufeng, Yao, Xiaokang, Gao, Chaofeng, Shen, Kang, Jia, Wenyong, Zhi, Jiahuan, Cai, Suzhi, Song, Zhicheng, Li, Jingjie, Zhang, Yanyun, Lu, Song, Liu, Kun, Dong, Chaomin, Wang, Qian, Zhou, Yudong, Yao, Wei, Zhang, Yujian, Zhang, Hongmei, Zhang, Zaiyong, Hang, Xiaochun, An, Zhongfu, Liu, Xiaogang, Huang, Wei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-11-2021; Nature Publishing Group
• Subjects: 639/301/1019; 639/624/399; Biomaterials; Carboxylic acids; Cations; Chemistry and Materials Science; Chromophores; Condensed Matter Physics; Confining; Crystals; Data encryption; Efficiency; Emitters; Energy levels; Ionic crystals; Materials Science; Molecular Conformation; Nanotechnology; Optical and Electronic Materials; Optoelectronics; Phosphorescence; Phosphors; Radiative recombination
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-021-01073-5

High-efficiency blue phosphorescence emission is essential for organic optoelectronic applications. However, synthesizing heavy-atom-free organic systems having high triplet energy levels and suppressed non-radiative transitions—key requirements for efficient blue phosphorescence—has proved difficult. Here we demonstrate a simple chemical strategy for achieving high-performance blue phosphors, based on confining isolated chromophores in ionic crystals. Formation of high-density ionic bonds between the cations of ionic crystals and the carboxylic acid groups of the chromophores leads to a segregated molecular arrangement with negligible inter-chromophore interactions. We show that tunable phosphorescence from blue to deep blue with a maximum phosphorescence efficiency of 96.5% can be achieved by varying the charged chromophores and their counterions. Moreover, these phosphorescent materials enable rapid, high-throughput data encryption, fingerprint identification and afterglow display. This work will facilitate the design of high-efficiency blue organic phosphors and extend the domain of organic phosphorescence to new applications.
A strategy to confine phosphorescent organic chromophores within ionic crystals proves effective in suppressing non-radiative recombination channels and increasing the phosphorescence efficiency of blue-emitting heavy-atom-free emitters.