Understanding the liquid–liquid (water–hexane) interface

Liquid-Liquid Interface-Assisted Self-Assembly of Ag-Doped ZnO Nanosheets for Atomic Switch Application

Developing facile and inexpensive methods for obtaining large-area two-dimensional semiconducting nanosheets is highly desirable for mass-scale device application. Here, we report a method for producing uniform and large-area films of a Ag-doped ZnO (AZO) nanosheet network via self-assembly at the hexane-water interface by controlling the solute/solvent ratio. The self-assembled film comprises of uniformly tiled nanosheets with size ∼1 μm and thicknesses∼60-100 nm. Using these films in a Pt/AZO/Ag structure, an atomic switch operation is realized. The switching mechanism is found to be governed by electrochemical metallization with nucleation as the rate-limiting step. Our results establish the protocol for large-scale device applications of AZO nanosheets for exploring advanced atomic switch-based neuromorphic systems.

Interfacial Thermal Conductivity and Its Anisotropy

There is a significant effort in miniaturizing nanodevices, such as semi-conductors, currently underway. However, a major challenge that is a significant bottleneck is dissipating heat generated in these energy-intensive nanodevices. In addition to being a serious operational concern (high temperatures can interfere with their efficient operation), it is a serious safety concern, as has been documented in recent reports of explosions resulting from many such overheated devices. A significant barrier to heat dissipation is the interfacial films present in these nanodevices. These interfacial films generally are not an issue in macro-devices. The research presented in this paper was an attempt to understand these interfacial resistances at the molecular level, and present possibilities for enhancing the heat dissipation rates in interfaces. We demonstrated that the thermal resistances of these interfaces were strongly anisotropic; i.e., the resistance parallel to the interface was significantly smaller than the resistance perpendicular to the interface. While the latter is well-known—usually referred to as Kapitza resistance—the anisotropy and the parallel component have previously been investigated only for solid-solid interfaces. We used molecular dynamics simulations to investigate the density profiles at the interface as a function of temperature and temperature gradient, to reveal the underlying physics of the anisotropy of thermal conductivity at solid-liquid, liquid-liquid, and solid-solid interfaces.