Cross-Linked Polyphosphazene Nanospheres Boosting Long-Lived Organic Room-Temperature Phosphorescence

作者：Yongfeng Zhang, Xiaohong Chen, Jianrong Xu, Qinglun Zhang, Liang Gao, Zhonghao Wang, Lunjun Qu, Kaiti Wang, Youbing Li, Zhengxu Cai, Yanli Zhao, Chaolong Yang · 发表于：Journal of the American Chemical Society · 年份：2022 · DOI：10.1021/jacs.2c02076 · 被引用次数：277 · 研究领域：Luminescence and Fluorescent Materials、Organic Light-Emitting Diodes Research、Perovskite Materials and Applications

Long-lived organic room-temperature phosphorescence (RTP) has sparked intense explorations, owing to the outstanding optical performance and exceptional applications. Because triplet excitons in organic RTP experience multifarious relaxation processes resulting from their high sensitivity, spin multiplicity, inevitable nonradiative decay, and external quenchers, boosting RTP performance by the modulated triplet-exciton behavior is challenging. Herein, we report that cross-linked polyphosphazene nanospheres can effectively promote long-lived organic RTP. Through molecular engineering, multiple carbonyl groups (C═O), heteroatoms (N and P), and heavy atoms (Cl) are introduced into the polyphosphazene nanospheres, largely strengthening the spin–orbit coupling constant by recalibrating the electronic configurations between singlet (S n ) and triplet (T n ) excitons. In order to further suppress nonradiative decay and avoid quenching under ambient conditions, polyphosphazene nanospheres are encapsulated with poly(vinyl alcohol) matrix, thus synchronously prompting phosphorescence lifetime (173 ms longer), phosphorescence efficiency (∼12-fold higher), afterglow duration time (more than 20 s), and afterglow absolute luminance (∼19-fold higher) as compared with the 2,3,6,7,10,11-hexahydroxytriphenylene precursor. By measuring the emission intensity of the phosphorescence, an effective probe based on the nanospheres is developed for visible, quantitative, and expeditious detection of v...