• 文献标题:   Graphene-molecule-graphene single-molecule junctions to detect electronic reactions at the molecular scale
  • 文献类型:   Article
  • 作  者:   YANG C, YANG CY, GUO YL, FENG JF, GUO XF
  • 作者关键词:  
  • 出版物名称:   NATURE PROTOCOLS
  • ISSN:   1754-2189 EI 1750-2799
  • 通讯作者地址:  
  • 被引频次:   0
  • DOI:   10.1038/s41596-023-00822-x EA APR 2023
  • 出版年:   2023

▎ 摘  要

The ability to measure the behavior of a single molecule during a reaction implies the detection of inherent dynamic and static disordered states, which may not be represented when measuring ensemble averages. Here, we describe the building of devices with graphene-molecule-graphene single-molecule junctions integrated into an electrical circuit. These devices are simple to build and are stable, showing tolerance to mechanical changes, solution environment and voltage stimulation. The design of a conductive channel based on a single molecule enables single-molecule detection and is sensitive to variations in physical properties and chemical structures of the detected molecules. The on-chip setup of single-molecule junctions further offers complementary metal-oxide-semiconductor (CMOS) compatibility, enabling logic functions in circuit elements, as well as deciphering of reaction intermediates. We detail the experimental procedure to prepare graphene transistor arrays as a basis for single-molecule junctions and the preparation of nanogapped carboxyl-terminal graphene electrodes by using electron-beam lithography and oxygen plasma etching. We describe the basic design of a molecular bridge with desired functions and terminals to form covalent bonds with electrode arrays, via a chemical reaction, to construct stably integrated single-molecule devices with a yield of 30-50% per chip. The immobilization of the single molecules is then characterized by using inelastic electron tunneling spectra, single-molecule imaging and fluorescent spectra. The whole protocol can be implemented within 2 weeks and requires users trained in using ultra-clean laboratory facilities and the aforementioned instrumentation. Graphene-based single-molecule junctions, integrated with an electrical circuit, facilitate the detection of electronic, optical and mechanical properties of reactions at the molecular scale.