Fabozzi Filippo Giovanni, Cojal González José D, Severin Nikolai, Rabe Jürgen P, Hecht Stefan
DWI-Leibniz Institute for Interactive Materials, Aachen 52074, Germany.
Department of Chemistry and Center for the Science of Materials Berlin, Humboldt-Universität zu Berlin, Berlin 12489, Germany.
ACS Nano. 2024 Dec 10;18(49):33664-33670. doi: 10.1021/acsnano.4c12708. Epub 2024 Nov 22.
Studying molecular materials at the nanoscale allows us to gain a deeper understanding of supramolecular structure formation and serves as the basis for rationally controlling the resulting interfacial properties. Here, we describe the formation of extended Moiré patterns resulting from the assembly of dipolar π-conjugated molecules on highly oriented pyrolytic graphite at the liquid-solid interface as characterized by scanning tunneling microscopy (STM). By switching the bias of the sample and thus the orientation of the external electric field in the vicinity of the STM junction, structural reorganization of the molecular building blocks and the resulting organic 2D crystal is induced and can conveniently be monitored by the appearance and disappearance of the Moiré patterns. Importantly, the formation and loss of the Moiré patterns are fully reversible, providing exquisite control over epitaxial molecular crystals. Our approach provides fundamental insights into the supramolecular organization and resulting superstructure formation of incommensurable 2D lattices upon applying an electric field and enables the rational tuning of Moiré patterns as a key step toward the potential integration of organic 2D crystals in molecular nanodevices.
在纳米尺度上研究分子材料，使我们能够更深入地理解超分子结构的形成，并为合理控制由此产生的界面性质奠定基础。在此，我们描述了由偶极π共轭分子在液固界面的高度取向热解石墨上组装而形成的扩展莫尔条纹图案，这一过程通过扫描隧道显微镜（STM）进行表征。通过切换样品的偏压，进而改变STM结附近外部电场的方向，分子构建单元和由此产生的有机二维晶体的结构会发生重组，并且可以通过莫尔条纹图案的出现和消失方便地进行监测。重要的是，莫尔条纹图案的形成和消失是完全可逆的，这为外延分子晶体提供了精确的控制。我们的方法为施加电场时不可公度二维晶格的超分子组织和由此产生的超结构形成提供了基本见解，并能够合理调节莫尔条纹图案，这是朝着将有机二维晶体潜在集成到分子纳米器件迈出的关键一步。
