Chen Liang, Chen Xin, Ma Rui, Lin Kun, Li Qiang, Lang Jian-Ping, Liu Chunyu, Kato Kenichi, Huang Ling, Xing Xianran
Beijing Advanced Innovation Center for Materials Genome Engineering, Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing 100083, China.
College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, China.
J Am Chem Soc. 2022 Aug 3;144(30):13688-13695. doi: 10.1021/jacs.2c04316. Epub 2022 Jul 25.
Overcoming thermal quenching is an essential issue in the practical application of luminescent materials. Herein, we found that negative thermal expansion (NTE) can achieve the thermal enhancement of luminescence in molecular materials based on three metal-organic frameworks CuX-bpy (X = Cl, Br, I; bpy = 4,4'-bipyridine). All complexes exhibit NTE on the -axis, and the strongest NTE leads to a contraction of the Cu...Cu distance in CuCl-bpy, which further intensifies the luminescence emission. This phenomenon indicates the existence of thermally enhanced charge transfer. Moreover, the origin of the distinction in charge transfer attributed to the different valence states of the copper is investigated through the combined studies of X-ray photoelectron spectroscopy, X-ray absorption near-edge structure, and density functional theory calculations. This research provides a new approach to modulating the luminescence thermal enhancement by NTE.
克服热猝灭是发光材料实际应用中的一个关键问题。在此，我们发现基于三种金属有机框架CuX-bpy（X = Cl、Br、I；bpy = 4,4'-联吡啶）的负热膨胀（NTE）能够实现分子材料发光的热增强。所有配合物在a轴上均表现出NTE，最强的NTE导致CuCl-bpy中Cu...Cu距离收缩，这进一步增强了发光发射。该现象表明存在热增强电荷转移。此外，通过结合X射线光电子能谱、X射线吸收近边结构和密度泛函理论计算，研究了归因于铜不同价态的电荷转移差异的起源。本研究为通过NTE调节发光热增强提供了一种新方法。
