Scientists report a systematic study involving theoretical and experimental approaches to evaluate the Li-ion storage capability in 2D atomic sheets of nonlayered MoO2. They describe a new process - polymer-assisted reduction - to make atomically flat 2D sheets of MoO2. Since MoO2 is not a 2D material, this process opens a new pathway to make 2D nanostructures from non-layered materials. By successfully making 2D atomic sheets of MoO2, the researchers fabricated a battery electrode in which the Li ion diffusion and electron transport are exceptionally fast.
Researchers have looked closer at the Hall effect in narrow graphene devices - so-called graphene nanoribbons and nanoconstrictions. They were puzzled when they found that the quantization of the conductance was destroyed in some samples - especially because these particular samples were optimized for low edge disorder and low contamination. As it turned out, this effect had been predicted by several theoretical physicists twenty years ago, but largely ignored since no experimental evidence was ever found.
Optics and mesoscopic physics teams have discovered a new cooling mechanism concerning electronic components made of graphene deposited on boron nitride. The efficiency of this mechanism allowed them to reach electric intensities at the intrinsic limit of the laws of conduction. This new mechanism, which exploits the two-dimensional nature of the materials opens a 'thermal bridge' between the graphene sheet and the substrate. Researchers have demonstrated the effectiveness of this mechanism by imposing in graphene levels of electrical current still unexplored, up to the intrinsic limit of the material and without any degradation of the device.
Efficient electrocatalysts lie at the heart of a series of significant energy conversion and storage technologies, and atomically precise understanding of the influences of component dopants is crucial for looking into the reaction mechanism and controlled synthesis of the desired electrocatalysts. Graphitic carbon nitride is a promising electrocatalytic material owing to its intrinsically high N content and abundant edge sites. This material has been researched towards some of the most significant electrocatalytic reactions including oxygen reduction/evolution reaction and hydro evolution reaction. New work has comprehensively explored the influences of component elements within graphitic carbon nitride motiety for electrocatalytic reactions.
Since the ground-breaking discovery of two-dimensional (2D) black phosphorus (phosphorene), it has created global research interest and triggered ripples of excitement in the scientific community due to its intriguing optical, mechanical and electronic properties. Researchers have looked into the state-of-the-art development of phosphorene, including its structure, preparation routes, anisotropic properties, device applications as well as the bottlenecks encountered by the research community. However, there still are quite a few obstacles and opportunities for scientists to tackle.
Researchers have reported on improved performance of graphene-based moisture barrier layers. By combining catalytic CVD and ALD they created in scalable fashion nanolaminates of few-layer graphene and aluminium oxid. Unlike previous reports, this new approach exploits the synergy between different materials and growth techniques. These nanolaminates also are a potential material to be included in standard multi-stacked barrier layers to enhance the performance of existing ALD aluminium oxide and produce next generation moisture barriers.
Currently, most graphene-based innovations are not yet at the level of large-scale commercial production. But public and private investments into graphene and its applications in products are large and whichever production methods eventually turn out to be successful, exposure to humans or the environment somewhere along the value chain or life-cycle of the material or product should be anticipated timely. A new review paper offers suggestions on how potential nanospecific safety issues can be addressed, by who and at what stage of the innovation process.
Just like traditional paper origami that results in complicated 3D structures from 2D paper, graphene origami allows the design and fabrication of carbon nanostructures that are not naturally existing but of desirable properties. In a new report, researchers describe how p-type and n-type doping of 2D sheets like graphene in selected areas could be exploited as two 'colors' to guide the sheets into preferred folded shapes where complementarily doped areas maximize their mutual overlap.