Electrochemically fabricated molecule–electrode contacts for molecular electronics

Connecting molecules to electrodes is key for a range of applications. Conventional methods typically involve a spontaneous reaction of thiol/disulfide-terminated molecules with metal surfaces. Although modifying metal surfaces with thiol chemistry is simple, it is limited to forming a specific S–metal bonding, which is labile and hence there are concerns regarding its mechanical instability. In addition, spontaneous grafting requires long processing times to achieve high molecular coverages on the surface, which adds challenges for manufacturing devices comprising molecular films. Electrochemical methods for forming molecular films on surfaces offer powerful advantages over traditional methods, including reaction acceleration, molecular coverage control, and guiding the chemical bonding at the molecule‒electrode interface. Electrochemical grafting enables connecting molecules to various types of electrodes including those that cannot be functionalized by other methods. More recently, electrochemical approaches were expanded to enable connecting 2D materials to electrodes, opening a realm of possibilities for hybrid technologies. In this opinion, we survey the recent progress in electrochemical methods for connecting (bio) molecules to electrodes for advancing molecular and bioelectronics. •This review discusses electrochemical methods for connecting molecules to electrodes.•The first two sections survey the conventional methods for forming organic films on surfaces.•The third section discusses electrochemical methods for functionalising different electrodes.•The last section discusses alternative methods for forming molecular films on surfaces.•Conclusion and outlook highlight new trends of a hybrid molecular electronics and 2D materials technology. [Display omitted]