Real-Time Monitoring the Dynamics of Coordination-Driven Self-Assembly by Fluorescence-Resonance Energy Transfer

It is quite challenging to investigate the dynamics of coordination-driven self-assembly due to the existence of multiple intermediates and many possible processes. By taking advantage of the high sensitivity and efficiency of fluorescence-resonance energy transfer (FRET), FRET was successfully employed to real-time monitor the dynamic behavior of coordination-driven self-assembly. The Förster energy transfer efficiencies and kinetic aspects of a series of discrete, well-defined metallacycles have been determined. Moreover, the dynamic characteristics of these supramolecular assemblies, such as the dynamic ligand exchange, anion-induced disassembly and reassembly, and stability in different solvents, have been investigated by using FRET

Single-Crystal Antimonene Films Prepared by Molecular Beam Epitaxy: Selective Growth and Contact Resistance Reduction of the 2D Material Heterostructure

Single-crystal antimonene flakes are observed on sapphire substrates after the postgrowth annealing procedure of amorphous antimony (Sb) droplets prepared by using molecular beam epitaxy at room temperature. The large wetting angles of the antimonene flakes to the sapphire substrate suggest that an alternate substrate should be adopted to obtain a continuous antimonene film. By using a bilayer MoS₂/sapphire sample as the new substrate, a continuous and single-crystal antimonene film is obtained at a low growth temperature of 200 °C. The results are consistent with the theoretical prediction of the lower interface energy between antimonene and MoS₂. The different interface energies of antimonene between sapphire and MoS₂ surfaces lead to the selective growth of antimonene only atop MoS₂ surfaces on a prepatterned MoS₂/sapphire substrate. With similar sheet resistance to graphene, it is possible to use antimonene as the contact metal of 2D material devices. Compared with Au/Ti electrodes, a specific contact resistance reduction up to 3 orders of magnitude is observed by using the multilayer antimonene as the contact metal to MoS₂. The lower contact resistance, the lower growth temperature, and the preferential growth to other 2D materials have made antimonene a promising candidate as the contact metal for 2D material devices