2D Confined High-pressure Nanoreactors
Chemical reactions conducted at high pressures provide opportunities for realising new synthesis chemistries and achieving novel states of matter. Many industrial chemical reactors operate at pressures of few thousand atmospheres but facile application of very high pressures (>1 GPa), where interesting reactions can occur and new materials can be realized, is challenging. Confinement of reactants within nanoscale spaces of low dimensional materials (pores such as zeolites and metal organic frameworks and carbon nanotubes) has been shown to provide non-equilibrium conditions for synthesis of novel molecules3 and tuning of chemical reactivity. While few studies have reported chemistry within zero dimensional pores and one dimensional nanotubes, organic reactions in confined spaces between 2D materials have yet to be explored. Here we demonstrate that reactants confined between atomically thin sheets of graphene or hexagonal boron nitride experience pressures as high as 7 GPa, which allows the propagation of solvent-free organic reactions that ordinarily do not occur under standard conditions. Specifically, we show that cyclodehydrogenation of hexaphenylbenzene without catalysts as a proof of concept and oxidative polymerisation of dopamine into sheet-like crystalline structure are enabled by the effective high pressure experienced by the reactants between the graphene layers. The graphene/polydopamine/graphene reaction results in a novel composite material that possesses higher Young’s modulus (430 GPa) than pure graphene layers (300 GPa) and an exceptionally low water vapor transmission rate of < 0.1 g-m-2-day-1 – nearly an order of magnitude lower than the state-of-the-art water-diffusion barriers for graphene and hBN. Our results demonstrate a facile, general approach for performing new high-pressure chemistry based on confinement of reactants within graphene layers that provides opportunities for realizing new materials with extraordinary properties.

Exploring Two-Dimensional Materials for Future Electronic Devices
Due to our life style changes, data created exponentially and continuously increases. To respond to the huge Data created, conventional Si device scaling down for angstrom era, and 3D stacking device and introduction of disruptive device should be considered. However, the process technology and material performance of Si devices are gradually reaching their limits, and the development of new materials, processes and device architectures is required to overcome these limitations. Graphene and 2D Materials have an ultra-thin crystal structure with a stable surface state. For example, among diverse 2D materials, MoS2 has a great potential in logic transistor because of its high mobility, and no short channel effect. In this talk, we will introduce 2D material designs from growth to integration via interface property control to realize the Angstrom era: (i) material growth for wafer-scale and precise layer control, (ii) interface control for doping, contact resistance, and adhesion/pattern, and (iii) Interconnect with a low resistance metal barrier and
ultralow dielectric material for multi-stacking device. Finally, we will briefly discuss (iv) disruptive devices for future computing systems such as low-power synaptic device.

Registration: https://hkuems1.hku.hk/hkuems/ec_hdetail.aspx?guest=Y&ueid=86927