Towards supramolecular chemistry with inorganic 2D nanomaterial building blocks

自从突破性地发现石墨中的各个层可以稳定地分离以产生原子级薄的石墨烯纳米片以来，层状晶体受到了极大的关注。除了石墨之外，诸如过渡金属二硫属化物或III-VI族半导体的广泛范围的无机材料以其层状形式广泛丰富。作为一个过程，分层到单个纳米片对材料科学和技术产生了变革性的影响，通过打开在二维（2D）剥离形式中发现的令人兴奋的特性，而不一定在它们的大块对应物中看到。此外，剥离产生具有高纵横比和表面积的材料。近年来，从根本上研究许多2D材料的物理特性取得了重大进展。此外，已经证明它们可以在液体中剥离，从而从溶液中进行处理，这有利于将这些材料用作从电子到能量存储或电催化的广泛潜在应用中的构建块。然而，到目前为止，2D材料的化学性质还很少被探索。特别是，广泛缺乏湿化学官能化序列，以改变光学，电子和表面性能。为了充分发挥它们的潜力，有必要对其性能进行微调。在该提案中，将基于研究液体剥离无机2D材料与各种有机分子和聚合物的非共价相互作用，探索通用和高通量的功能化。纳米材料的光学指纹对它们的化学环境高度敏感，将用于跟踪诸如掺杂或光致电荷转移等相互作用。基于这种高通量筛选，将鉴定用于用阴离子、阳离子或中性官能部分官能化的合适的锚基团。这将使人们能够获得各种具有定制特性的2D材料，这些材料可以通过旋涂、滴铸或印刷等现有技术从液体中加工而成。反过来，这将允许使用超分子化学制造多组分无机/有机混合体系。这样的系统是非常感兴趣的基础研究和各种应用，因为可以利用不同类别的纳米材料之间的协同效应。

Since the ground-breaking discovery that individual layers in graphite can be stably isolated to yield atomically thin graphene nanosheets, layered crystals have received enormous attention. In addition to graphite, a broad range of inorganic materials such as transition metal dichalcogenides or III-VI semiconductors are widely abundant in their layered form. As a process, delamination to individual nanosheets has had a transformative effect on materials science and technology by opening up exciting properties found in the two-dimensional (2D) exfoliated forms, not necessarily seen in their bulk counterparts. In addition, exfoliation creates materials with high aspect ratio and surface area. Recent years have seen significant progress to fundamentally study physical properties of a number of 2D materials. In addition, it was demonstrated that they can be exfoliated in liquids giving access to processing from solution which is beneficial for using these materials as building blocks in a broad range of potential applications from electronics to energy storage or electrocatalysis. However, up until now, the chemistry of the 2D materials is only little explored. In particular, wet chemical functionalization sequences to modify optical, electronic and surface properties are widely lacking. To fully exploit their potential, it will be necessary to fine-tune their properties.Within this proposal, a versatile and high throughput functionalization will be explored based on studying the noncovalent interaction of liquid exfoliated inorganic 2D materials with a broad range of organic molecules and polymers. The optical fingerprints of the nanomaterials which are highly sensitive to their chemical surrounding will be used to track interactions such as doping or photoinduced charge transfer. Based on this high throughput screening, suitable anchor groups for the functionalization with anionic, cationic or neutral functional moieties will be identified. This will give access to a broad range of 2D materials with tailored properties which can be processed from liquids by established techniques such as spin coating, drop casting or printing. In turn, this will allow for the fabrication of multicomponent inorganic/organic hybrid systems using supramolecular chemistry. Such systems are of great interest for both fundamental studies and various applications, as synergistic effects between different classes of nanomaterials can be exploited.