Abstract

Controlling the structure formation of molecules on surfaces is fundamental for creating molecular nanostructures with tailored properties and functionalities and relies on tuning the subtle balance between intermolecular and molecule-surface interactions. So far, however, reliable rules of design are largely lacking, preventing the controlled fabrication of self-assembled functional structures on surfaces. In addition, while so far many studies focused on varying the molecular building blocks, the impact of systematically adjusting the underlying substrate has been less frequently addressed. Here, we elucidate the potential of tailoring the mesoscopic island shape by tuning the interactions at the molecular level. As a model system, we have selected the molecule dimolybdenum tetraacetate on three prototypical surfaces, Cu(111), Au(111) and CaF₂(111). While providing the same hexagonal geometry, compared to Cu(111), the lattice constants of Au(111) and CaF₂(111) differ by a factor of 1.1 and 1.5, respectively. Our high-resolution scanning probe microscopy images reveal molecular-level information on the resulting islands and elucidate the molecular-level design principles for the observed mesoscopic island shapes. Our study demonstrates the capability to tailor the mesoscopic island shape by exclusively tuning the substrate lattice constant, in spite of the very different electronic structure of the substrates involved. This work provides insights for developing general design strategies for controlling molecular mesostructures on surfaces.

中文翻译：

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量身定制分子岛的形状：微观相互作用对介观结构的影响

摘要

控制表面上分子的结构形成是创建具有定制特性和功能的分子纳米结构的基础，并且依赖于调节分子间相互作用与分子-表面相互作用之间的微妙平衡。然而，到目前为止，在很大程度上缺乏可靠的设计规则，从而阻止了在表面上自组装功能结构的受控制造。另外，尽管到目前为止，许多研究都集中在改变分子构件上，但系统地调节底层底物的影响却很少得到解决。在这里，我们阐明了通过在分子水平上调节相互作用来调整介观岛形状的潜力。作为模型系统，我们选择了三个原型表面Cu（111），Au（111）和CaF上的四乙酸二钼酸分子₂（111）。尽管提供了相同的六边形几何形状，但与Cu（111）相比，Au（111）和CaF ₂（111）的晶格常数分别相差1.1和1.5倍。我们的高分辨率扫描探针显微镜图像揭示了所得岛状物的分子水平信息，并阐明了所观察到的介观岛状的分子水平设计原理。我们的研究表明，尽管所涉及的衬底的电子结构非常不同，但可以通过专门调整衬底的晶格常数来定制介观岛形状。这项工作为开发用于控制表面分子介观结构的一般设计策略提供了见识。