Theoretical Studies of Inorganic Fullerenes and Fullerene-Like Nanoparticles

Density Functional Theory Study of Cu-Modified B12N12 Nanocage as a Chemical Sensor for Carbon Monoxide Gas

The development of efficient B₁₂N₁₂-based toxic gas sensors has received considerable attention from the scientific community. Thus, in this regard, quantum chemical calculations were performed using density functional theory (DFT) at the B97D/6-31G(d,p) level for all of the studied systems. Modification of copper on B₁₂N₁₂ results in five optimized structures, named CuB₁₁N₁₂ and B₁₂N₁₁Cu (doped structures), Cu@b₆₆ and Cu@b₆₄ (decorated structures), and Cu@B₁₂N₁₂ (encapsulated structure). The results indicate that the CO gas weakly physisorbed on the B₁₂N₁₂ nanocage. It was found that the gas adsorption performance of B₁₂N₁₂ is improved due to the introduction of the Cu atom, but the interaction between CO and B₁₂N₁₁Cu, Cu@B₁₂N₁₂, Cu@b₆₄, and Cu@b₆₆ nanocages is strong, limiting the applications as a sensor. Particularly, the CuB₁₁N₁₂ system shows moderate adsorption (E_ads = -0.6 eV) and a high electronic sensitivity (ΔE_gap = 81.6%) toward CO gas, compared to other modified systems. Furthermore, based on the sensor performance analysis, it was found that CuB₁₁N₁₂ presented low recovery time (14 ms) and high selectivity for CO detection, making it a promising fast response sensor. Finally, our results demonstrated the capability of CuB₁₁N₁₂ as a superior sensor material for applications involving the selective detection of CO gas.

Topology of transition metal dichalcogenides: the case of the core-shell architecture

Non-planar architectures of the traditionally flat 2D materials are emerging as an intriguing paradigm to realize nascent properties within the family of transition metal dichalcogenides (TMDs). These non-planar forms encompass a diversity of curvatures, morphologies, and overall 3D architectures that exhibit unusual characteristics across the hierarchy of length-scales. Topology offers an integrated and unified approach to describe, harness, and eventually tailor non-planar architectures through both local and higher order geometry. Topological design of layered materials intrinsically invokes elements highly relevant to property manipulation in TMDs, such as the origin of strain and its accommodation by defects and interfaces, which have broad implications for improved material design. In this review, we discuss the importance and impact of geometry on the structure and properties of TMDs. We present a generalized geometric framework to classify and relate the diversity of possible non-planar TMD forms. We then examine the nature of curvature in the emerging core-shell architecture, which has attracted high interest due to its versatility and design potential. We consider the local structure of curved TMDs, including defect formation, strain, and crystal growth dynamics, and factors affecting the morphology of core-shell structures, such as synthesis conditions and substrate morphology. We conclude by discussing unique aspects of TMD architectures that can be leveraged to engineer targeted, exotic properties and detail how advanced characterization tools enable detection of these features. Varying the topology of nanomaterials has long served as a potent methodology to engineer unusual and exotic properties, and the time is ripe to apply topological design principles to TMDs to drive future nanotechnology innovation.

Field-effect transistors based on WS2 nanotubes with high current-carrying capacity

We report the first transistor based on inorganic nanotubes exhibiting mobility values of up to 50 cm(2) V(-1) s(-1) for an individual WS2 nanotube. The current-carrying capacity of these nanotubes was surprisingly high with respect to other low-dimensional materials, with current density at least 2.4 × 10(8) A cm(-2). These results demonstrate that inorganic nanotubes are promising building blocks for high-performance electronic applications.