Search

We have investigated the electronic and magnetic properties of zigzag nanoribbons (ZNRs) of arsenene and antimonene both in black phosphorene (BP) phase and hexagonal phase by using first principles calculations. Firstly, a novel metallic edge state emerges in the mid of the bulk band gap for ZNRs of all the systems. Secondly, edge magnetism have also been systematically studied for these systems by considering different magnetic configurations. An intra-edge antiferromagnetic semiconducting state is found to be the ground state for the ZNRs of arsenene and antimonene. Since the edges of ZNRs are easily saturated by Hydrogen and Oxygen atoms when the samples are exposed to the air in the experiment, we further investigate influence of edge passivation of Hydrogen or Oxygen atoms and find the edge magnetism vanished under H-passivation but still restored under O-atoms passivation. Thus the electronic and magnetic properties of the ZNRs can be effectively controlled by intentionally passivation with various elements. We hope these interesting electronic and magnetic properties of the ZNRs of arsenene/antimonene are useful for future applications in nanoelectronic and spintronic devices.

The enduring goal in condensed matter physics is to search for controlled magnetism in semiconducting materials. Based on first principles DFT calculations, we systematically investigate the electronic and magnetic properties of zigzag arsenene nanoribbons (ZAsNRs). We find that metallic edge states originate in the middle of bulk band gap for different widths of ZAsNRs due to electronic instability. Besides, edge magnetism for different magnetic configurations of ZAsNRs, have been investigated to remove these instabilities. There occurs a transition from non-magnetic to magnetic and metallic to semi-conducting edge states and as a result an intra-edge antiferromagnetic (AFM) semiconducting ground state has been found. In order to tune the edge states, strain engineering is employed on magnetic ground state and found that at critical value of compressive strains (−6%), there happens a transition from magnetic to nonmagnetic (NM) and semiconductor to metal. We expect that these semiconducting properties can be controlled by edge magnetism and strain engineering and make ZAsNRs a best semiconducting material which can be used as promising candidate for device applications in semiconducting industry.

In view of the growing concern about energy management issues, sodium ion batteries (SIBs) as cheap and environmentally friendly devices have increasingly received wide research attentions. The high current rate and long cycle-life of SIBs are considered as two key parameters determining its potential for practical applications. In this work, the rigid single-crystalline anatase TiO2 nanosheets (NSs) with a thickness of ∼4 nm has been firstly prepared, based on which a stable nanostructured network consisting of ultrathin anatase TiO2 NSs homogeneously anchored on graphene through chemical bonding (TiO2 NSs-G) has fabricated by hydrothermal process and subsequent calcination treatment. The morphology, crystallization, chemical compositions and the intimate maximum contact between TiO2 NSs and graphene are confirmed by TEM, SEM, XRD, XPS and Raman characterizations. The results of electrochemical performance tests indicated that the TiO2 NSs-G hybrid network could be consider as a promising anode material for SIBs, in assessment of its remarkably high current rate and long cycle-life aside from the improved specific capacity, rate capability and cycle stability.

Taking advantages of the monodisperse TiO2 nanosheets (NSs) with high active crystal face exposure and the tunable localized surface plasmon resonance (LSPR) properties of Au@Ag nanorods (NRs), this study demonstrated that TiO2 NSs film with trace amount of Au@Ag NRs modification possess a strong enhancement of photocurrent response, which was remarkably inhibited with the addition of mercury (II) ions (Hg(2+)). Based on the selective decrease of photocurrent with the addition of Hg(2+), a simple photoelectrochemical (PEC) sensor has been assembled. The PEC sensor exhibits wide linear range (0.01-10nM), low detection limit (2.5 pM), satisfying selectivity, reproducibility and acceptable stability for Hg(2+) detection. The feasibility of this method for practical application in human serum has been evaluated and the result was satisfactory. This PEC sensing method would provide a potential application for Hg(2+) detection in clinical diagnosis.