Thiol-free self-assembled oligoethylene glycols enable robust air-stable molecular electronics
Thiol-free self-assembled oligoethylene glycols enable robust air-stable molecular electronics
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DOI：
10.1038/s41563-019-0587-x
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发表时间：
2020-01-20
期刊：
影响因子：
41.2
通讯作者：
Chiechi, Ryan C.
中科院分区：
文献类型：
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作者：
Qiu, Xinkai;Ivasyshyn, Viktor;Chiechi, Ryan C.
自组装单分子膜（Self-assembled monolayers，SAMs）是一种新型的表面修饰材料，它是由乙二醇醚和富勒烯组成的化学吸附分子，可以在金属表面形成均匀的自组装双层膜，并通过原位交换实现功能化。金属-硫醇盐键的相对简单和通用的化学性质使硫醇盐自组装膜成为一系列应用中的优选选择，但脆弱性和在空气中氧化的倾向限制了它们的长期使用。在这里，我们报告的形成无硫醇自组装单和双层的乙二醇醚，它结合到钴金属的表面，通过自发的化学吸附的乙二醇醚官能化的富勒烯。所制备的组件是在衬底和环境界面处呈现富勒烯笼的双层。随后暴露于官能化的乙二醇醚取代最顶层的乙二醇醚官能化的富勒烯，并且所得的组件将官能团暴露于环境界面。这些层表现出硫醇盐SAM的关键特性，但它们对环境条件稳定数周，如由烷基官能化乙二醇醚的SAM形成的隧道结的性能所示。乙二醇醚官能化螺吡喃纳入混合单分子膜导致可逆的，光驱动的电导切换。乙二醇醚的自组装是硫醇盐SAM的直接替代品，保留了它们所有的有用特性，同时避免了金属-硫醇盐键的缺点。
Chemisorbed molecules combining glycol-ether moieties and fullerenes are shown to form uniform and air-stable self-assembled bilayers on coinage metals, and are amenable to versatile functionalization by in-place exchange of the top layer.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 a range of applications, yet fragility and a tendency to oxidize in air limit their long-term use. Here, we report the formation of thiol-free self-assembled mono- and bilayers 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, and 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 tunnelling junctions formed from SAMs of alkyl-functionalized glycol ethers. Glycol ether-functionalized spiropyrans incorporated into mixed monolayers lead 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.