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The chirality-dependent property of CNTs hinders their application in next-generation electronic devices. There is thereby an urgent need to explore new 1D nanotubes with stable and controllable electronic properties. Here, we investigate the charge transport properties of several BAs nanotubes (BAsNTs) with different shapes by using first-principles density functional theory (DFT) and non-equilibrium Green's function (NEGF) methods. It is found that these BAs nanotubes are all semiconductors regardless of chirality and cross section shape, and their band gaps are very close (∼1 eV), which could overcome the chirality-dependent property shortcoming of CNTs and thus make them potential candidates for application in the field of electronic devices. In addition, we demonstrate that the encapsulation of H2O, CO2 and SO2 molecules has different effects on the BAsNTs with different cross section shapes. Particularly, when inserting H2O into the circular BAsNT, the negative differential resistance (NDR) phenomenon and a metal–semiconductor transition are observed. This novel characteristic makes BAsNTs potential candidates for application in gas sensors. The discovery may provide new opportunities for the design of next-generation BAsNT-based electronic devices and gas sensors. [ABSTRACT FROM AUTHOR]

There is a growing awareness that the structures of boron phosphide (BP) nanoribbons have a significant impact on their electronic transport properties, which will further affect their application in many fields, including energy conversion and nanoelectronic devices. By using the first principle density functional theory and non-equilibrium Green's function calculations, we investigate the electronic transport properties of graphene-like hexagonal zigzag BP nanoribbons with edges terminated by hydrogen atoms (–H) or hydroxyl groups (–OH) and the effect of twisting and bending deformations on their transport properties. Our results show that the electronic transport properties of the BP-H nanoribbons become poor after twisting to 45°, while twisting does not reduce the electronic transport properties of BP-OH nanoribbons. When we combine BP-H and BP-OH nanoribbons into a heterosheet, the effect of twist angle is similar to that for the BP-H nanoribbon. Another interesting finding is that for the BP-OH nanoribbons, there is a significant negative differential resistance (NDR) with a giant peak-to-valley ratio (PVR) of up to 90 when it is curled into an arch, which can be applied as an electric switch. Our detailed insights may provide a novel strategy to tune the electronic transport properties of BP nanoribbon-based structures. [ABSTRACT FROM AUTHOR]

The electronic structures of the armchair Fe2Si nanotubes are calculated by using the SGGA+U method. Novel heterostructure devices are prepared composed of single-wall Fe2Si nanotubes (Fe2Si NTs) and carbon nanotubes (CNTs). The results indicate that the (4,4) Fe2Si NT is a ferromagnetic half metal with 100% spin-polarization ratio at the Fermi energy level. These heterojunctions have spin-polarized transport properties but their spin-polarization ratios are relatively low. Interestingly, the (13,0) CNT–(n,n) Fe2Si NT–(13,0) CNT devices are all semiconductors but others are metallic. This study suggests that adding the novel Fe2Si NTs endows the CNTs with spin-polarized property and provides very valuable results for better understanding of the electronic structures of the heterostructure. [ABSTRACT FROM AUTHOR]

Edge reconstructions of two-dimensional (2D) materials play a central role in determining the electronic transport properties of nanodevices. However, it is not feasible to study the relationship between edge reconstruction and electronic properties using experimental methods because of the complexity of the experimental environment and the diversity of edge reconstruction. Herein, we have combined density functional theory (DFT) calculations and the nonequilibrium Green's function (NEGF) method to investigate the inner physical mechanism of platinum diselenide (PtSe 2 ) nanoribbons, revealing distinctive negative differential resistance (NDR) behaviors in different nanoribbons with various edge reconstructions. The armchair PtSe 2 nanoribbons with different edge reconstructions are all metallic, while the zigzag PtSe 2 nanoribbons are semiconducting when the ratio of Pt to Se atoms at the edge is 1 : 2. These results reveal the internal source of the difference in the electron transport properties of PtSe 2 nanoribbons with different edge reconstructions, providing new ideas for the design of novel multifunctional PtSe 2 semiconducting and conducting electronic nanodevices with NDR properties., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

MoS 2 nanosheets can be applied as electrochemical biosensors to selectively and sensitively respond to the surrounding environment and detect various biomolecules due to their large specific surface area and unique physicochemical properties. In this paper, single-layer or few-layer MoS 2 nanosheets were prepared by an improved liquid phase stripping method, and then combining the unique material characteristics of MoS 2 and the metallic property of Au nanoparticles (AuNPs), Au@MoS 2 composite nanosheets were synthesized based on MoS 2 nanosheets. Then, the structure and properties of MoS 2 nanosheets and Au@MoS 2 composite nanosheets were comprehensively characterized. The results proved that AuNPs were successfully loaded on MoS 2 nanosheets. At the same time, on the basis of the successful preparation of Au@MoS 2 composite nanosheets, an electrochemical biosensor targeting dopamine was successfully constructed by cyclic voltammetry. The linear detection range was 0.5-350 μM, and the detection limit was 0.2 μM. The high-sensitive electrochemical detection of dopamine has been achieved, which provides a new idea for the application of MoS 2 -based nanomaterials in the biosensing of neurotransmitters. In addition, density functional theory (DFT) was used to explore the electrochemical performance of Au@MoS 2 composite nanosheets. The results show that the adsorption of Au atoms on the MoS 2 2D structure improves the conductivity of MoS 2 nanosheets, which theoretically supports the possibilities of its application as a platform for the ultrasensitive detection of neurotransmitters or other biomolecules in the field of disease diagnosis., Competing Interests: There are no competing interests to declare., (This journal is © The Royal Society of Chemistry.)