Xinliang Feng, Technische Universität Dresden
Advances in Organic 2D Crystals—From On-Water Surface Chemistry to Functional Applications.
Written by Vineeth Venugopal
In his Symposium X presentation, Xinliang Feng of the Technische Universität Dresden spoke about inorganic two-dimensional (2D) crystals such as dichalcogenides, boron nitride, black phosphorus, metal oxides, and nitrides beyond graphene. He noted that there has been much less development in organic 2D crystalline materials, including the bottom-up organic/polymer synthesis of graphene nanoribbons, 2D metalorganic frameworks, and 2D polymers/supramolecular polymers, as well as the supramolecular approach to 2D organic nanostructures.
Organic two-dimensional soft matter are 2D nanostructures that can be easily deformed by thermal stresses or thermal fluctuations at about room temperature. They include graphene oxide, 2D supramolecular organic nanoarchitectures, from surface synthesis, amphiphile, colloids, biomembrane, and liquid crystal. Organic 2D materials can include synthetic graphene, 2D polymers/supramolecular polymers, single/ few layer 2D COFs/MOFs, and crystalline polymer nanosheets, for example. These have applications, for example, in energy storage, photo/electro catalysis, sensors, superconductivity, topological insulators, and spintronics.
Recently, Feng’s research group observed fractional edge excitations in nanographene spin chains. This has led to work on G-nanostructures and organic 2D materials such as 2D polymers and conjugated polymers.
One of the central chemical challenges is to realize a controlled polymerization in two distinct dimensions under thermodynamic/kinetic control in solution and at the surface/interface. In this talk, Feng presented his group’s recent efforts in bottom-up synthetic approaches toward novel organic 2D crystals with structural control at the atomic/molecular level. On-water surface synthesis provides a powerful synthetic platform by exploiting surface confinement and enhanced chemical reactivity and selectivity.
Feng presented a surfactant-monolayer-assisted interfacial synthesis (SMAIS) method that is highly efficient to promote programmable assembly of precursor monomers on the water surface and subsequent 2D polymerization in a controlled manner. Two-dimensional conjugated polymers and coordination polymers belong to such materials classes. The unique 2D crystal structures with possible tailoring of conjugated building blocks and conjugation lengths, tunable pore sizes and thicknesses, as well as impressive electronic structures, make them highly promising for a range of applications in electronics, optoelectronics, and spintronics. Other physicochemical phenomena and application potential of organic 2D crystals, such as in membranes, were also discussed.
Symposium X—MRS/The Kavli Foundation Frontiers of Materials features lectures aimed at a broad audience to provide meeting attendees with an overview of leading-edge topics.