Current–voltage characteristics of single molecule junctions are governed both by the energy level alignment of molecular orbitals with respect to the Fermi level of the electrodes and by the hybridization of electronic structures at the interface between the molecule and the electrodes. While there have been many studies on tuning the former, only a few works intended to control the latter. In the present study, we demonstrate that molecular junctions based on carbazole oligomers showed a current rectification behavior due to asymmetric–symmetric control of electronic hybridization between the molecule and electrodes at the both terminals. The carbazole oligomers originally showed an asymmetric molecular orbital and, hence, electronic hybridization with the electrodes because of the electric dipole moment. Symmetric electronic hybridization was achieved when the applied electric field between electrodes deformed molecular orbital to be symmetric. This is a novel way to control charge transport in single-molecule junctions.

中文翻译：

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基于咔唑低聚物中分子轨道的电压依赖性变形的单分子整流器†

单分子结的电流-电压特性既受分子轨道相对于电极费米能级的能级排列的控制，又受分子与电极之间界面电子结构的杂化的影响。尽管有许多关于调整前者的研究，但只有少数作品旨在控制后者。在本研究中，我们证明了基于咔唑低聚物的分子连接表现出电流整流行为，这是由于分子和两个末端电极之间电子杂交的不对称控制所致。咔唑低聚物最初显示出不对称的分子轨道，因此由于电偶极矩而与电极发生电子杂交。当电极之间施加的电场使分子轨道变形为对称时，实现了对称的电子杂交。这是一种控制单分子结中电荷传输的新颖方法。