武汉大学Zhen Li研究组取得一项新突破。他们开发了一类纯有机荧光余辉材料，并描述了其可见光激发、内在机制、可调颜色、以及低成本的实际应用。相关论文于2023年5月27日发表在《德国应用化学》杂志上。

在该研究中，研究人员观察到荧光染料一旦被分散在聚合物基质中，会出现荧光余辉强度和持续时间的差异，这是由于共面和刚性染料的化学结构导致的反向系统穿越速度缓慢(kRISC)和延迟荧光寿命延长(τDF)。为验证这一机制，不同聚合物被用于调制基于溶剂效应的单线态-三线态能量分裂。此外，吖啶黄商品化薄膜与纯化后相比表现出蓝移荧光，kRISC更慢(~100 s^-1)和更长的τDF(0.6 s)。

通过从Acf向罗丹明B的能量转移，余辉颜色可以被进一步的调制，最大的荧光量子产率为42.4%。这类材料可被用在颜色可调光材料中，作为白光下低成本($2/50000标签)防伪标签。

据了解，具有可见光荧光余辉的纯有机材料具有很大的潜在应用价值。

附：英文原文

Title: Purely Organic Fluorescence Afterglow: Visible-Light-Excitation, Inherent Mechanism, Tunable Color, and Practical Applications with Very Low Cost

Author: Jiaqiang Wang, Yujie Yang, Kexin Li, Liyao Zhang, Zhen Li

Issue&Volume: 2023-05-27

Abstract: Purely organic materials with visible light excitable fluorescence afterglow are promising for applications. Herein, fluorescence afterglow with various intensity and duration was observed on fluorescent dyes once being dispersed in polymer matrix, thanks to their slow reverse intersystem crossing rate (kRISC) and long delayed fluorescence lifetime (τDF) derived from the coplanar and rigid chemical structure of the dyes..To verify the mechanism, different polymers were used to tune singlet-triplet splitting energy based on the solvent effect. And commercial acriflavine film showed blue shifted fluorescence compared to purified one, with slower kRISC (~100 s -1 ) and longer τDF (0.6 s). Via energy transfer from Acf to rhodamine B, the afterglow color was further regulated, with the largest fluorescence quantum yield of 42.4%. It was demonstrated that the materials worked on color tunable light sources, and low-cost ($2 for 50,000 labels) anti-counterfeit labels recognized by white light.

DOI: 10.1002/anie.202304020

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202304020