Preparation and Application of Microelectrodes at the Single‐Molecule Scale

Molecular electronics offers a potential solution for the miniaturization of electronics beyond conventional silicon electronics. A key goal of molecular electronics is to fabricate the single‐molecule junction with the functions of electronic units. The term “molecular junction” means a molecular cluster or a single molecule incorporated between two microelectrodes, and electrons are transported across it. The methods of constructing molecular junctions dynamically were developed, such as STM‐BJ, AFM‐BJ, and MCBJ, providing precise control of the gap and easy measurement of thousands of junctions. Electrodes based on these techniques are commonly called microelectrodes because at least one dimension is on the micron scale. In this manuscript, we summarize the preparation methods of microelectrodes and their application in single‐molecule measurements. In addition, we discuss the electrode factor that influences the molecular electrical properties, such as material, curvature radius and cone angle, and further provide a brief prospect of molecular electronics. We present a technique for constructing molecular junctions dynamically at the single‐molecule scale, mainly including STM‐BJ, AFM‐BJ and MCBJ. The types of microelectrodes corresponding to each setup are introduced, and the preparation methods of microelectrodes are summarized. Meanwhile, we discuss the electrode factor that influences the molecular electrical properties, such as material, curvature radius and cone angle, and a brief prospect of molecular electronics is also provided in this manuscript.