School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK.
School of Materials, University of Manchester, Manchester M13 9PL, UK.
Nat Commun. 2016 Jul 7;7:12168. doi: 10.1038/ncomms12168.
Van der Waals assembly of two-dimensional crystals continue attract intense interest due to the prospect of designing novel materials with on-demand properties. One of the unique features of this technology is the possibility of trapping molecules between two-dimensional crystals. The trapped molecules are predicted to experience pressures as high as 1 GPa. Here we report measurements of this interfacial pressure by capturing pressure-sensitive molecules and studying their structural and conformational changes. Pressures of 1.2±0.3 GPa are found using Raman spectrometry for molecular layers of 1-nm in thickness. We further show that this pressure can induce chemical reactions, and several trapped salts are found to react with water at room temperature, leading to two-dimensional crystals of the corresponding oxides. This pressure and its effect should be taken into account in studies of van der Waals heterostructures and can also be exploited to modify materials confined at the atomic interfaces.
由于有望设计具有按需特性的新型材料，二维晶体的范德华组装继续引起强烈兴趣。该技术的独特功能之一是有可能在二维晶体之间捕获分子。据预测，被捕获的分子将经历高达 1 GPa 的压力。在这里，我们通过捕获压敏分子并研究它们的结构和构象变化来报告这种界面压力的测量结果。使用拉曼光谱法测量厚度为 1nm 的分子层，发现压力为 1.2±0.3GPa。我们进一步表明，这种压力可以引发化学反应，并且几种被捕获的盐在室温下与水反应，导致相应氧化物的二维晶体。在研究范德华异质结构时应考虑到这种压力及其影响，也可以利用这种压力来修饰在原子界面限制的材料。
