MOE Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, Lehn Institute of Functional Materials, School of Chemistry, Sun Yat-Sen University, 510275, Guangzhou, China.
Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 201204, Shanghai, China.
Nat Commun. 2018 Jun 19;9(1):2401. doi: 10.1038/s41467-018-04833-1.
Two-dimensional (2D) metal-organic frameworks have exhibited a range of fascinating attributes, of interest to numerous fields. Here, a calcium-based metal-organic framework with a 2D layered structure has been designed. Dual emissions relating to intralayer excimers and interlayer trapped excitons are produced, showing excitation-dependent shifting tendency, characteristic of a low dimensional semiconductor nature. Furthermore, the layer stacking by weak van der Waals forces among dynamically coordinated DMF molecules enables exfoliation and morphology transformation, which can be achieved by ultrasound in different ratios of DMF/HO solvents, or grinding under appropriate humidity conditions, leading to nano samples including ultrathin nanosheets with single or few coordination layers. The cutting down of layer numbers engenders suppression of interlayer exciton-related emission, resulting in modulation of the overall emitting color and optical memory states. This provides a rare prototypical model with switchable dual-channel emissions based on 2D-MOFs, in which the interlayer excitation channel can be reversibly tuned on/off by top-down exfoliation and morphology transformation.
二维（2D）金属有机骨架具有一系列令人着迷的特性，引起了众多领域的关注。在这里，设计了一种具有二维层状结构的基于钙的金属有机骨架。产生了与层内激基缔合物和层间捕获激子有关的双重发射，表现出与低维半导体性质有关的激发依赖性移动趋势。此外，通过动态配位 DMF 分子之间的弱范德华力进行层堆叠，实现了剥离和形态转变，可以通过不同比例的 DMF/HO 溶剂中的超声或在适当湿度条件下的研磨来实现，从而得到包括具有单个或少数配位层的超薄纳米片在内的纳米样品。减少层数会抑制层间激子相关发射，从而调制整体发射颜色和光学记忆状态。这提供了一个基于 2D-MOF 的罕见的可切换双通道发射原型模型，其中通过自上而下的剥离和形态转变，可以可逆地调节层间激发通道的开/关。
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