Gu Chun, Zhang Hang, Yu Junhong, Shen Qiang, Luo Guoqiang, Chen Xuan, Xue Ping, Wang Zhengbang, Hu Jianbo
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Laboratory for Shock Wave and Detonation Physics, Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900, China.
Nano Lett. 2021 Jan 27;21(2):1102-1107. doi: 10.1021/acs.nanolett.0c04492. Epub 2021 Jan 6.
Metal-organic frameworks (MOFs) provide a novel strategy to precisely control the alignment of molecules to enhance exciton diffusion for high-performance organic semiconductors. In this paper, we characterize exciton dynamics in highly ordered and crystalline porphyrin MOF nanofilms by time-resolved photoluminescence and femtosecond-resolved transient absorption spectroscopy. Results suggest that porphyrin MOF nanofilms could be a promising candidate for high-performance organic photovoltaic semiconductors in which the diffusion coefficient and diffusion length of excitons are 9.0 × 10 cm s and 16.6 nm, respectively, comparable with or even beyond that of other excellent organic semiconductors. Moreover, by monitoring real-time exciton dynamics it is revealed that excitons in MOF nanofilms undergo high-efficient intermolecular hopping and multiexciton annihilation due to the short intermolecular distance and aligned molecular orientation in MOF structure, thus providing new insights into the underlying physics of exciton dynamics and many-body interaction in molecular assembled systems.
金属有机框架（MOFs）提供了一种新颖的策略，可精确控制分子排列以增强高性能有机半导体中的激子扩散。在本文中，我们通过时间分辨光致发光和飞秒分辨瞬态吸收光谱来表征高度有序且结晶的卟啉MOF纳米薄膜中的激子动力学。结果表明，卟啉MOF纳米薄膜可能是高性能有机光伏半导体的一个有前途的候选材料，其中激子的扩散系数和扩散长度分别为9.0×10⁻⁹ cm² s⁻¹和16.6 nm，与其他优异的有机半导体相当甚至超过它们。此外，通过监测实时激子动力学发现，由于MOF结构中分子间距离短且分子取向排列，MOF纳米薄膜中的激子经历高效的分子间跳跃和多激子湮灭，从而为分子组装系统中激子动力学和多体相互作用的潜在物理机制提供了新的见解。
