含柔性空间间隔基团的荧光-长寿命室温磷光双重发射有机材料的设计及其在生物快速检测与成像领域的应用

Organic materials with persistent room-temperature phosphorescence (pRTP) are emerging materials which break the traditional concept of only inorganic materials exhibit persistent phosphorescence at room-temperature. Their pRTP are naked eyes visible and very sensitive to external stimuli. Among kinds of pRTP, dual-emission of fluorescence and pRTP attracted considerable attentions because it not only can serve as detection regents for ratio analysis which showing strong ability of anti-interference and highly stability, but also could provide rapid detection and imaging simply by naked eyes. However, it is a common problem for these organic materials with dual-emission of fluorescence and pRTP that low pRTP intensity and short pRTP wavelength, in the only several reported cases of their bioimaging applications. In this project, based on our previously discovery and proposed “intermolecular groups conjugation” mechanism of organic pRTP materials, we will propose to synthesize a series of organic materials with dual-emission of fluorescence and pRTP, which exhibit highly emissive quantum yields, using a new design strategy of introduction of a soft spacer unit into the molecular structure to independently control the intensity and lifetime of pRTP. And preparation of microcrystals of these highly emissive organic materials with dual-emission of fluorescence and pRTP, by an ultrasound-induced seed assisted crystallization method. These obtained microcrystals will be used for rapid detection and imaging simply by naked eyes in biological applications. In this project, we will focus on studying the molecular design strategy, the mechanism of their pRTP, their stimuli-responsive properties, in order to reveal the tuning approach of the excited state life in organic materials with pRTP. The work being proposed in this project will push forward the development of those new organic functional materials with persistent phosphorescence. Furthermore, it will promote the fundamental investigation on luminescent behavior and excited state feature of organic molecules as well.

最近发展起来的有机长寿命室温磷光新材料其磷光裸眼可分辨，且对外界刺激具有灵敏响应。其中的荧光-长寿命磷光双重发射有机材料，适合作为比率型检测试剂，抗环境干扰能力强，稳定性高，还可实现裸眼分辨的快速检测与成像，受到了人们的高度重视。有机长寿命磷光材料生物成像应用仅有的几个例子都存在材料磷光发光效率较低，波长较短等问题。本项目拟根据我们前期探索提出的长寿命磷光“分子间基团共轭”机理，利用“柔性空间间隔基团”的分子结构设计策略，在晶体中分别独立调控长寿命磷光的发光效率与寿命，获得高效发光的双重发射材料。拟采用“超声诱导晶种辅助”方法制备其微晶，探索其在裸眼分辨生物快速检测与成像领域的应用。并力求明确其分子设计策略，阐明其发光机理和刺激响应机制，揭示其激发态调控的途径。本项目的成功实施，将促进有机长寿命磷光新材料的发展，还将促进对有机材料分子发光行为和激发态过程等基础科学问题认识的深化。

荧光-超长磷光双发射有机材料，适合作为比率型检测试剂，抗环境干扰能力强，稳定性高，还可实现裸眼分辨的快速检测与成像，受到了人们的高度重视。现有荧光-超长磷光双发射有机材料存在磷光发光效率较低，波长较短等问题。针对上述问题，本项目取得了一些一些成果：（1）揭示了咔唑衍生物晶体中关键异构体的本征超长磷光性质，并提出了“界面能量转移”策略，获得了发光寿命为0.10 s的640 nm红光有机荧光-超长磷光双发射材料；（2）深化了n、π基团的概念，设计了新的超长磷光分子TP，在TP@PVA聚合物复合体系中获得了具有高达33%量子效率的3.29 s超长磷光寿命新记录；并提出了“阶梯型能量转移”策略，在TP@PVA体系中共掺杂商用红光和近红外荧光分子，获得了发光寿命为0.2 s的810 nm近红外有机荧光-超长磷光双发射聚合材料；（3）详细研究了微乳液法制备有机荧光-超长磷光双发射材料纳米晶的工艺条件，初步探索了其在细胞成像的应用；（4）探索了其他类型双发射材料：（a）提出了利用晶体中弱分子间作用局域化并稳定自由基的策略，设计了灵敏可逆的光激活荧光-自由基发光双发射有机发光新材料；（b）揭示了有机荧光-TADF双发射材料力致发光颜色变化（动态力致发光）的分子结构和聚集体结构规律。项目相关成果在包括材料类顶级期刊Adv Mater、化学类顶级期刊Angew Chem Int Ed上发表标注SCI论文8篇，其中中科院1区论文4篇。获中国专利授权1项。本项目促进了有机荧光-超长磷光双发射等新材料的发展，也促进了对有机材料分子发光行为和激发态过程等基础科学问题认识的深化。