Dataset: Thiol-free Self-assembled Oligoethylene Glycols Enable Robust Air-stable Molecular Electronics

Self-assembled monolayers (SAMs) are widely used to engineer the surface properties of metals. The relatively simple and versatile chemistry of metal-thiolate bonds makes thiolate SAMs the preferred option in various applications, yet fragility and tendency to oxidize in air limit their long-term use. Here we report the formation of thiol-free self-assembled mono- and bi-layers of glycol ethers, which bind to the surface of coinage metals through the spontaneous chemisorption of glycol-ether-functionalized fullerenes. As-prepared assemblies are bilayers presenting fullerene cages at both the substrate and ambient interface. Subsequent exposure to functionalized glycol ethers displaces the topmost layer of glycol-ether-functionalized fullerenes; the resulting assemblies expose functional groups to the ambient interface. These layers exhibit the key properties of thiolate SAMs, yet they are stable to ambient conditions for several weeks, as shown by the performance of tunneling junctions formed from SAMs of alkyl-functionalized glycol ethers. Glycol-ether-functionalized spiropyrans incorporated into mixed monolayers leads to reversible, light-driven conductance switching. Self-assemblies of glycol ethers are drop-in replacements for thiolate SAMs that retain all of their useful properties while avoiding the drawbacks of metal-thiolate bonds.