西北工业大学黄维团队报道了可见光激发下分离分子的高效超长室温磷光。相关研究成果发表在2024年12月9日出版的国际知名学术期刊《美国化学会杂志》。

可见光激发的超长有机磷光（UOP）材料在各种实际应用中具有巨大的潜力。红移激发波长可以通过在有机分子中引入大的π共轭结构来实现，从而增加分子间的相互作用和耦合。然而，从孤立的分子中产生可见光激发的UOP是一个巨大的挑战。

该文中，研究人员开创了一种通过将有机分子掺杂到刚性聚合物中，来实现可见光激发UOP的策略。所得材料在环境条件下表现出高达2.226秒的超长寿命和42.6%的高磷光效率。令人印象深刻的是，掺杂1 wt%不同客体的聚乙烯醇薄膜，显示出蓝色和绿色可见光激发的UOP。

此外，它们显示出长时间的持续发光，在室温下持续30分钟以上。通过控制实验和理论计算，发现客体和PVA之间的氢键限制了分子运动，促进了高效UOP。单分子态内的分子内电荷转移导致低能级，从而导致红移吸收。

该项工作将为开发基于非晶态聚合物的可见光激发UOP开辟一条新途径，在环境条件下提供高效的UOP和长期持续的发光。

附：英文原文

Title: Efficient and Ultralong Room Temperature Phosphorescence from Isolated Molecules under Visible Light Excitation

Author: Huanyu Yang, Yuefei Wang, Xiaokang Yao, Huili Ma, Jiming Yu, Xian Li, Xing Wang, Xinyu Liang, Qiming Peng, Suzhi Cai, Zhongfu An, Wei Huang

Issue&Volume: December 9, 2024

Abstract: Visible-light-excited ultralong organic phosphorescence (UOP) materials hold significant potential for various practical applications. Red-shifted excitation wavelength can be achieved by introducing large π-conjugation structures into organic molecules, thereby increasing intermolecular interactions and coupling. However, generating visible-light-excited UOP from isolated molecules poses a great challenge. Herein, we pioneered a strategy to achieve visible-light-excited UOP by doping organic molecules into a rigid polymer. The resulting materials exhibit an ultralong lifetime of up to 2.226 s and a high phosphorescence efficiency of 42.6% under ambient conditions. Impressively, poly(vinyl alcohol) films doped with 1 wt % different guests demonstrate blue and green visible-light-excited UOP. Moreover, they show long-persistent luminescence, lasting over 30 min at room temperature. Through control experiments and theoretical calculations, we discovered that hydrogen bonding between the guests and PVA confines the molecular motion, promoting efficient UOP. The intramolecular charge transfer within the single molecular state contributes to the low energy level, thus leading to the red-shifted absorption. This work will open a new way for developing visible-light-excited UOP based on amorphous polymers, offering highly efficient UOP and long-persistent luminescence under ambient conditions.

DOI: 10.1021/jacs.4c08889

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c08889