Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany.
Department of Chemistry, Philipps-Universität Marburg, 35037, Marburg, Germany.
Nat Commun. 2023 Mar 21;14(1):1554. doi: 10.1038/s41467-023-37203-7.
Since molecular materials often decompose upon exposure to radiation, lithographic patterning techniques established for inorganic materials are usually not applicable for the fabrication of organic nanostructures. Instead, molecular self-organisation must be utilised to achieve bottom-up growth of desired structures. Here, we demonstrate control over the mesoscopic shape of 2D molecular nanosheets without affecting their nanoscopic molecular packing motif, using molecules that do not form lateral covalent bonds. We show that anisotropic attractive Coulomb forces between partially fluorinated pentacenes lead to the growth of distinctly elongated nanosheets and that the direction of elongation differs between nanosheets that were grown and ones that were fabricated by partial desorption of a complete molecular monolayer. Using kinetic Monte Carlo simulations, we show that lateral intermolecular interactions alone are sufficient to rationalise the different kinetics of structure formation during nanosheet growth and desorption, without inclusion of interactions between the molecules and the supporting MoS substrate. By comparison of the behaviour of differently fluorinated molecules, experimentally and computationally, we can identify properties of molecules with regard to interactions and molecular packing motifs that are required for an effective utilisation of the observed effect.
由于分子材料在暴露于辐射下常常会分解，因此为无机材料建立的光刻图案化技术通常不适用于制造有机纳米结构。相反，必须利用分子自组织来实现所需结构的自下而上生长。在这里，我们展示了在不影响其纳米级分子堆积模式的情况下，对二维分子纳米片的介观形状进行控制，使用的分子不会形成横向共价键。我们表明，部分氟化并五苯之间的各向异性吸引力库仑力导致明显拉长的纳米片的生长，并且在生长的纳米片和通过部分解吸完整的分子单层来制造的纳米片之间，伸长的方向不同。使用动力学蒙特卡罗模拟，我们表明，仅侧向分子间相互作用就足以合理说明纳米片生长和解吸过程中结构形成的不同动力学，而无需包括分子与支撑 MoS 衬底之间的相互作用。通过实验和计算比较不同氟化分子的行为，我们可以确定对于有效利用所观察到的效应，分子的相互作用和分子堆积模式所需的性质。
