He Yanjin, Wang Yongtao, Li Xueming, Guo Yanjun, Ma Lei
Guangxi Key Laboratory of Electrochemical and Magneto-chemical Function Materia, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China.
Guangxi Key Laboratory of Electrochemical and Magneto-chemical Function Materia, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2023 Mar 5;288:122161. doi: 10.1016/j.saa.2022.122161. Epub 2022 Nov 26.
Poor photostability has become a major obstacle of organic fluorescent dyes (OFD) used as light conversion agent. To explore the intrinsic mechanisms of photodegradation and highly efficient means to enhance photostability, here, three s-triazine dyes and two 1,3,5-triphenylbenzene luminescent agents were designed and synthesized. Further, the relationships of photostability, intramolecular charge transfer effect, energy gap between singlet and triplet, and active oxygen generating capacity are analyzed and discussed. AIE activity, solid-state fluorescence emission, light conversion quality, and photostability combined with thermostability show TPT-DB (2,4,6-tris(4-(3,6-ditertbutyl-9H-carbazol-9-yl)phenyl)-1,3,5-triazine) is the best light conversion agent among of the dyes, whose photosynthetic photon flux density at 400-500 nm and 600-700 nm in doping film increased successively to 6.20% and 25.78% of the blank film, emission intensity can maintain 93.4% of the initial value after intensified UV radiation of 20 h (365 nm, 40 w), and has good thermal stability, Td up to 374 °C. Furthermore, oxygen-free environment was confirmed to be the most effective measure to enhance the photostability of OFD, thereby a simple and efficient method is adopted to block the diffusion of oxygen and significantly enhance the photostability of OFD by amphiphilic ethylene-vinyl alcohol copolymer. The work not only provides an excellent light conversion agent, but also clears the obstacles for the large-scale application of OFD as light conversion agents.
光稳定性差已成为用作光转换剂的有机荧光染料（OFD）的主要障碍。为了探索光降解的内在机制以及提高光稳定性的高效方法，本文设计并合成了三种三嗪染料和两种1,3,5-三苯基苯发光剂。此外，还分析和讨论了光稳定性、分子内电荷转移效应、单重态和三重态之间的能隙以及活性氧生成能力之间的关系。通过聚集诱导发光（AIE）活性、固态荧光发射、光转换质量和结合热稳定性的光稳定性表明，TPT-DB（2,4,6-三（4-（3,6-二叔丁基-9H-咔唑-9-基）苯基）-1,3,5-三嗪）是这些染料中最佳的光转换剂，其掺杂膜在400 - 500 nm和600 - 700 nm处的光合光子通量密度依次提高到空白膜的6.20%和25.78%，在365 nm、40 w的紫外光强化辐射20 h后，发射强度可保持初始值的93.4%，并且具有良好的热稳定性，热分解温度高达374℃。此外，证实无氧环境是提高OFD光稳定性的最有效措施，因此采用一种简单有效的方法通过两亲性乙烯 - 乙烯醇共聚物来阻止氧气扩散并显著提高OFD的光稳定性。这项工作不仅提供了一种优异的光转换剂，还清除了OFD作为光转换剂大规模应用的障碍。
