基于侧基多通道和对称性破缺效应的分子电导调控  

Multiple-channel and symmetry-breaking effects on molecular conductance via side substituents

作　　者：郝杰 汪博宇 赵璁 霍雅妮 王进莹 贾传成 郭雪峰 Jie Hao;Boyu Wang;Cong Zhao;Yani Huo;Jinying Wang;Chuancheng Jia;Xuefeng Guo(Center of Single-Molecule Sciences,Institute of Modern Optics,Frontiers Science Center for New Organic Matter,Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China;Network for Computational Nanotechnology,School of Electrical and Computer Engineering,Purdue University,Indiana 47907,USA;Beijing National Laboratory for Molecular Sciences,National Biomedical Imaging Center,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China)

机构地区：[1]Center of Single-Molecule Sciences,Institute of Modern Optics,Frontiers Science Center for New Organic Matter,Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology,College of Electronic Information and Optical Engineering,Nankai University,Tianjin 300350,China [2]Network for Computational Nanotechnology,School of Electrical and Computer Engineering,Purdue University,Indiana 47907,USA [3]Beijing National Laboratory for Molecular Sciences,National Biomedical Imaging Center,College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China

出　　处：《Science China Materials》2024年第6期1994-1999,共6页中国科学（材料科学）（英文版）

基　　金：primary financial support from the Natural Science Foundation of Beijing (2222009);the National Key R&D Program of China (2022YFE0128700,2021YFA1200102,and 2021YFA1200101);the National Natural Science Foundation of China (22173050,21727806,22150013,and 21933001)。

摘　　要：化学取代是有效调节分子电导,产生多通道输运、量子干涉效应和其他机制的关键方法.但分子骨架和侧基之间存在复杂的相互作用,目前仍未被研究清楚.在本工作中,我们结合扫描隧道显微镜裂结实验技术和第一性原理计算方法,深入研究了具有不同σ和π侧基的分子电导.实验结果及理论分析表明,σ侧基的加入引起了分子前线轨道的对称性破缺并加剧了分子内散射,从而导致电导的降低.相反,π侧基引入了额外的电荷传输通道,实现了电荷传输的多通道效应,增加了分子的电导.这些发现为未来分子功能化和分子电子器件的设计提供了坚实的基础.Chemical substitution represents a pivotal method that enables effective modulation of molecular con-ductance and production of multiple transport channels,quantum interference effects,and other mechanisms.How-ever,the intricate interplay that occurs between the molecular backbone and the side motifs remains largely unexplored.This study explores the conductance characteristics of molecular junctions that feature differentσandπside groups by using a synergistic approach that combines scanning tunneling mi-croscope break junction experiments with the results of first-principles calculations.Our analysis shows that the in-corporation ofσ-side groups induces symmetry breaking in the frontier orbitals and increases intramolecular scattering,which then leads to reduced conductance.Conversely,the integration ofπ-side groups augments the molecular con-ductance through the multiple-channel effect,by which an additionalπpathway is introduced for charge transport.The findings reported here provide valuable insights into both molecular functionalization and the future design of potential molecular electronic devices.

关 键 词：side substituent multiple-channel effect symmetry-breaking effect single-molecule junction 

分 类 号：O641[理学—物理化学]