厦门大学洪文晶团队报道了σ–σ堆叠的超分子结。相关研究成果于2022年7月28日发表在《自然—化学》。

分子间电荷输运在有机电子材料和生物系统中起着至关重要的作用。迄今为止，分子材料和电子器件中分子间电荷传输的实验研究仅限于涉及π–π堆叠相互作用的共轭系统。

该文中，研究人员证明了相邻非共轭分子之间的σ–σ堆叠相互作用为通过超分子结的电荷传输提供了高效途径。在两个非共轭环己烷硫醇或单锚定金刚烷分子之间形成的σ–σ堆叠分子结的电导，与在π-共轭苯环之间形成的π–π堆叠分子结的电导相当。电流-电压特性和闪烁噪声分析表明，电极对之间存在堆叠的分子结，并表现出穿透空间电荷传输的特性。密度泛函理论计算与非平衡格林函数方法相结合表明，具有σ–σ堆积相互作用的两个分子之间发生有效电荷输运。

附：英文原文

Title: σ–σ Stacked supramolecular junctions

Author: Feng, Anni, Zhou, Yu, Al-Shebami, Mohammed A. Y., Chen, Lichuan, Pan, Zhichao, Xu, Wei, Zhao, Shiqiang, Zeng, Biaofeng, Xiao, Zongyuan, Yang, Yang, Hong, Wenjing

Issue&Volume: 2022-07-28

Abstract: Intermolecular charge transport plays an essential role in organic electronic materials and biological systems. To date, experimental investigations of intermolecular charge transport in molecular materials and electronic devices have been restricted to conjugated systems in which π–π stacking interactions are involved. Herein we demonstrate that the σ–σ stacking interactions between neighbouring non-conjugated molecules offer an efficient pathway for charge transport through supramolecular junctions. The conductance of σ–σ stacked molecular junctions formed between two non-conjugated cyclohexanethiol or single-anchored adamantane molecules is comparable to that of π–π stacked molecular junctions formed between π-conjugated benzene rings. The current–voltage characteristics and flicker noise analysis demonstrate the existence of stacked molecular junctions formed between the electrode pairs and exhibit the characteristics of through-space charge transport. Density functional theory calculations combined with the non-equilibrium Green’s function method reveal that efficient charge transport occurs between two molecules configured with σ–σ stacking interactions.

DOI: 10.1038/s41557-022-01003-1

Source: https://www.nature.com/articles/s41557-022-01003-1