Stereoelectronic Effect-Induced Conductance Switching in Aromatic Chain Single-Molecule Junctions

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• 作者：Na Xin ; Jinying Wang ; Chuancheng JiaZitong Liu ; Xisha Zhang ; Chenmin Yu ; Mingliang Li ; Shuopei Wang ; Yao Gong ; Hantao Sun ; Guanxin Zhang ; Zhirong Liu ; Guangyu Zhang ; Jianhui Liao ; Deqing Zhang ; Xuefeng Guo
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：17
• 期：2
• 页码：856-861
• 全文大小：457K
• ISSN：1530-6992

文摘

Biphenyl, as the elementary unit of organic functional materials, has been widely used in electronic and optoelectronic devices. However, over decades little has been fundamentally understood regarding how the intramolecular conformation of biphenyl dynamically affects its transport properties at the single-molecule level. Here, we establish the stereoelectronic effect of biphenyl on its electrical conductance based on the platform of graphene-molecule single-molecule junctions, where a specifically designed hexaphenyl aromatic chain molecule is covalently sandwiched between nanogapped graphene point contacts to create stable single-molecule junctions. Both theoretical and temperature-dependent experimental results consistently demonstrate that phenyl twisting in the aromatic chain molecule produces different microstates with different degrees of conjugation, thus leading to stochastic switching between high- and low-conductance states. These investigations offer new molecular design insights into building functional single-molecule electrical devices.