Li Huanhuan, Liu Yitong, Zhao Wei, Cao Hengyu, Yan Xin, Zhang Shuman, Yan Xi, Li Hui, Tao Ye, Xie Gaozhan, Li Wei, Chen Runfeng, Huang Wei
State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, Nanjing, 210023, China.
Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
Adv Mater. 2024 Nov;36(46):e2409338. doi: 10.1002/adma.202409338. Epub 2024 Sep 23.
The development of organic phosphorescent scintillators with high exciton utilization efficiency has attracted significant attention but remains a difficult challenge because of the inherent spin-forbidden feature of X-ray-induced triplet excitons. Herein, a design strategy is proposed to develop organic phosphorescent scintillators through thermally activated exciton release to convert stabilized spin-forbidden triplet excitons to spin-allowed singlet excitons, which enables singlet exciton-dominated multi-mode emission simultaneously from the lowest singlet, triplet, and stabilized triplet states. The resultant scintillators demonstrate a maximum photoluminescence efficiency of 65.8% and a minimum X-ray radiation detection limit of 110 nGy s; this allows efficient radiography imaging with a spatial resolution of ≈10.0 lp mm. This study advances the fundamental understanding of exciton dynamics under X-ray excitation, significantly broadening the practical use of phosphorescent materials for safety-critical industries and medical diagnostics.
具有高激子利用效率的有机磷光闪烁体的开发引起了广泛关注，但由于X射线诱导的三重态激子固有的自旋禁阻特性，这仍然是一个艰巨的挑战。在此，我们提出了一种设计策略，通过热激活激子释放来开发有机磷光闪烁体，将稳定的自旋禁阻三重态激子转化为自旋允许的单重态激子，从而实现从最低单重态、三重态和稳定三重态同时以单重态激子为主的多模式发射。所得闪烁体的最大光致发光效率为65.8%，最低X射线辐射检测限为110 nGy s；这使得能够以约10.0 lp mm的空间分辨率进行高效的射线照相成像。本研究推进了对X射线激发下激子动力学的基本理解，显著拓宽了磷光材料在安全关键行业和医学诊断中的实际应用。
