Efficient and Air-Stable Doping of Folded MoS₂ Nanosheets for Use in Field-Effect Transistors

Abstract

In recent years, doping technology has been widely used to modulate the electronic structure and transfer characteristics of two-dimensional (2D) materials. The addition of metal ions to 2D materials induces changes in the carrier type, which has promoted the development of 2D material-based optoelectronics. However, normal doping methods only modulate the top surface of a 2D material at the atomic level, which severely limits the doping efficiency and stability. Here, we report a method for highly efficient and air-stable doping of molybdenum disulfide (MoS 2 ) using a folded structure. Chloroauric acid (HAuCl 4 ) is used as the dopant to control the band gap of folded MoS 2 and gradually modify MoS 2 from an n-type to a p-type semiconductor. The intercavity of the folded structure creates a relatively closed environment, whereby the doped nanoparticles in the MoS 2 interlayer are protected. Therefore, three-face doping of the folded bilayer is achieved, that is, double-face doping of the top layer and single-face doping of the bottom layer; doping is thus unequivocally more efficient and stable, which leads to a change in the electronic band gap of MoS 2 . This study provides an effective method for highly efficient and stable doping of 2D materials.

ZnFe2O4/Graphitic Carbon Nitride Nano/Microcomposites for the Enhanced Electrochemical Sensing of H2O2

“…Compared with single metal oxides, nanosized spinel bimetal oxides were reported to show excellent electrocatalytic properties, which have already been utilized as advanced electrode architectures, photoelectric structures, and surface catalysts. ,− Among these compounds, ZnFe 2 O 4 (ZFO) reveals apparent merits in biosensors, attributed to the good catalytic activity, easy separation, low cost, and eco-friendliness. − For example, ZFO nanoparticles have been developed for the electrochemical determination of 5-fluorouracile, epinephrine, and glucose in recent years. − Nevertheless, the practical applications of pristine ZFO are often hampered, attributed to the poor inherent electronic conductivity and severe structural collapse induced by huge volumetric change and particle aggregation during the electrochemical reactions. Building a hierarchical hybrid nanostructure between nanosized ZFO and the conductive matrix is a prospective strategy to overcome the above-mentioned defects for the usage of pure ZFO materials. − Although the modified ZFO electrodes with carbonaceous matrixes (such as mesoporous carbon, amorphous carbon spheres, carbon nanotubes, and graphene) have been proved to exhibit remarkable electrochemical performances, − the simple and economical fabrication of hybrid composites with uniform micro/nanostructures and a respectable particle size for the detection of H 2 O 2 still remains a huge challenge.…”