Tunneling junctions comprising molecular monolayers can be considered devices because they are static and, using the appropriate electrode materials, can be wired together and packaged to perform useful functions. Self-assembled monolayers (SAMs) of thiolates are the most widely studied monolayers in this context because they are relatively easy to prepare and are capable of forming highly-ordered monolayers, facilitating the translation of observations from single-molecule junctions to large-area junctions. However, SAMs of thiolates are prone to (photo)oxidation and are only stable to ambient conditions for a matter of hours, particularly if they comprise molecules more complex than alkanes.<br/><br/>In this contribution, I will discuss our efforts to develop self-assembled bilayers (SABs) as an alternative platform for large-area molecular tunneling junctions. The SABs are anchored through noncovalent Pi-metal interactions that express polar (or aliphatic) chains at the ambient interface capable of interdigitating with arbitrary molecules bearing the same chain. This interdigitation forms the top half of the SAB and the self-assembly mirrors that of thiols; SABs exhibit self-repair, exchange and are capable of forming mixed phases. Unlike thiols, however, they are stable for up to one month in ambient conditions and are sufficiently mechanically stable to undergo exchange in operando, opening the potential for tuning the properties of a junction ex post facto.

Air-stable self-assembled bilayers form robust tunneling junctions

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.