基于界面能量转移的有机近红外超长磷光纳米材料及其应用

近几年发展起来的有机超长磷光材料其磷光裸眼可分辨，利用时间分辨技术可大幅度提高瞬态成像信噪比，在生物检测与成像上展现了优异效果，受到了人们的高度重视。然而已报道超长磷光材料其磷光集中在可见光区域，生物背景干扰强，稳态成像分辨率不高。且尚无合适分子设计策略大幅度调节其磷光颜色。本项目基于前期探索提出的双组分“界面能量转移”策略，拟利用近红外荧光分子作为疏水端的两亲性表面改性剂包覆稳定超长磷光纳米晶体，实现超长磷光向近红外荧光的能量转移，构筑有机近红外超长磷光纳米体系。糅合近红外和超长磷光两者优势，发展一类兼具稳态和瞬态高灵敏度的生物检测与成像有机新材料。并系统分析纳米体系结构、能量转移和激发态过程，研究其生物应用，探索其裸眼时间分辨进行快速检测的可能。项目的成功实施，将促进有机超长磷光和近红外荧光两类材料的发展，还将深化对纳米尺度下有机材料相界面长寿命激发态过程等基础科学问题的理解。

Organic materials with persistent room-temperature phosphorescence (pRTP) have obtained much attentions due to the excellent performance on bio-detection and bio-imaging. Their long-lived phosphorescence can be distinguished by naked eyes after removing the excitation source, which lead to a very high signal-to-noise ratio for time-resolved imaging. However, the phosphorescence peaks of these reported organic pRTP materials located in the visible spectrum, which resulted in low resolution of steady-state imaging because of the high biological background. There is no molecular design strategy to widely turn the pRTP color for these novel organic luminescent materials. In this project, organic nano-systems with persistent near-infrared (NIR) phosphorescence could be constructed from amphipathic surface modifiers coating pRTP nano-crystals, based on an interface energy transfer (IET) process of bi-component system reported recently by our group. The key amphipathic surface modifier contained a NIR fluorescent dye as its hydrophobic group. This hydrophobic NIR dye group could absorb onto the surface of pRTP nano-crystal and promote the IET process from the pRTP nano-crystal to the NIR dye, turning on a long-lived NIR luminescence of such organic nano-systems. Therefore, this new persistent NIR phosphorescent nano-systems can integrate of NIR and pRTP, providing a new kind of organic luminescent materials for highly sensitive imaging at both steady and transient states. The structures and excitons processes for energy transfer of these organic nano-systems will be systematic studied, and their applications for bio-detection and bio-imaging will be also investigated. Their possibilities for fast time-resolved detection by naked eyes will be explored too. This project could promote the developments of both NIR and pRTP organic materials, as well as the deep understand of the processes of long-lived excitons inside the interfaces of organic nano-systems.