Pan Xiaoyun, Montes Enrique, Rojas Wudmir Y, Lawson Brent, Vázquez Héctor, Kamenetska Maria
Department of Chemistry, Boston University, Boston, Massachusetts 02155, United States.
Institute of Physics, Czech Academy of Sciences, Cukrovarnická 10, Prague CZ-162 00, Czech Republic.
Nano Lett. 2023 Aug 9;23(15):6937-6943. doi: 10.1021/acs.nanolett.3c01540. Epub 2023 Jul 24.
We demonstrate enhanced electronic transport through dimer molecular junctions, which self-assemble between two gold electrodes in π-π stabilized binding configurations. Single molecule junction conductance measurements show that benzimidazole molecules assemble into dimer junctions with a per-molecule conductance that is higher than that in monomer junctions. Density functional theory calculations reveal that parallel stacking of two benzimidazoles between electrodes is the most energetically favorable due to the large π system. Imidazole is smaller and has greater conformational freedom to access different stacking angles. Transport calculations confirm that the conductance enhancement of benzimidazole dimers results from the changed binding geometry of dimers on gold, which is stabilized and made energetically accessible by intermolecular π stacking. We engineer imidazole derivatives with higher monomer conductance than benzimidazole and large intermolecular interaction that promote cooperative assembly of more transparent dimer junctions and suggest at the potential of molecular devices based on self-assembled molecular layers.
我们展示了通过二聚体分子结增强的电子传输，这些分子结在π-π稳定的结合构型中自组装于两个金电极之间。单分子结电导测量表明，苯并咪唑分子组装成二聚体结，其单分子电导高于单体结中的电导。密度泛函理论计算表明，由于大的π体系，两个苯并咪唑在电极之间的平行堆积在能量上最为有利。咪唑较小，具有更大的构象自由度以获得不同的堆积角度。输运计算证实，苯并咪唑二聚体的电导增强源于二聚体在金上结合几何结构的改变，这种改变通过分子间π堆积得以稳定并在能量上易于实现。我们设计了具有比苯并咪唑更高单体电导和大的分子间相互作用的咪唑衍生物，这些相互作用促进了更透明二聚体结的协同组装，并暗示了基于自组装分子层的分子器件的潜力。
