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/H₂O 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.

中文翻译：

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在剥落的超薄二维金属有机框架中调整激子和准分子发射。

二维（2D）金属有机框架已展现出一系列引人入胜的属性，许多领域都对此感兴趣。在此，已经设计了具有二维分层结构的钙基金属有机骨架。产生与层内受激准分子和层间受困激子有关的双重发射，显示出与激发有关的移动趋势，这是低维半导体性质的特征。此外，在动态配位的DMF分子之间通过弱范德华力堆叠的层使剥离和形态转变成为可能，这可以通过超声以不同比例的DMF / H ₂来实现。O溶剂，或在适当的湿度条件下研磨，会产生纳米样品，包括具有单个或很少配位层的超薄纳米片。减少层数可以抑制与层间激子有关的发射，从而调制总体发射颜色和光学存储状态。这提供了基于2D-MOF的具有可切换双通道发射的罕见原型模型，其中可以通过自上而下的剥落和形态转换可逆地打开/关闭层间激励通道。