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In this study, an electrode based on transition metal oxide molybdenum trioxide (MoO3) was fabricated and applied to electrochemical biosensing for glucose. In the process of making electrodes with relatively larger specific surface areas, an array of carbon nanotubes (CNTs) was deposited on a silicon substrate, and then, MoO3 was coated on the array of CNTs by chemical vapor deposition to produce a MoO3/CNTs/Si structure of three-dimensional electrochemical biosensing electrodes. Biosensing measurement was carried out in the concentration region from 20 μM to 7 mM of sodium hydroxide (NaOH). The highest sensitivity of 17.4 μA/μM cm2 was measured in the concentration range of 20–100 μM. The correlation coefficient of linear response (R2) was 0.9929, thus showing that MoO3/CNTs/Si is an excellent nonenzymatic glucose electrochemical sensor. [ABSTRACT FROM AUTHOR]

Two-dimensional molybdenum disulfide (MoS2) with multilayer hierarchical structures is generally considered to be able to provide more active sites and shorter diffusion channels for electrolytes, which make them extremely suitable for supercapacitor applications. Nevertheless, the MoS2 poor conductivity and rare surface area are the major technical obstacles. Herein, we demonstrated a honeycomb basis using carbon nanotubes (CNTs). The honeycomb-shaped carbon skeleton provides a relatively larger surface area to store more ions with a more stable and stronger structure to maintain long-term electrochemical tests. During MoS2 fabrication, MoOx was also synthesized onto CNTs. MoOx influenced the electrochemical test results. Thermal annealing was conducted to remove the MoOx attachments to assure the optimal capacitance value. For the particular composite honeycomb structure (MoS2/CNTs) used in this research, the specific capacitance increased from 4.7 F/g (CNTs) to 75 F/g (MoS2 + MoOx/CNTs), measured using cyclic voltammetry measurements. The specific capacitance further reached 425 F/g using thermal annealing at optimal temperature, 700 °C. The designed electrode materials demonstrated excellent electrochemical characteristics and had great potential for future electrochemical applications. [ABSTRACT FROM AUTHOR]

The study used multi-layer graphene, synthesized by thermal chemical vapor deposition, as the material for a homo-junction pn device formation. Due to the oxygen adsorption in air, the synthesized pristine graphene behaved as a p-type semiconductor. In order to modulate the graphene semiconductor type, the nitrogen plasma treatment with radio-frequency power as a parameter was used to transfer the semiconductor characteristics. The graphene-based field-effect transistor transfer characteristics were subsequently measured to confirm whether the modified graphene was p-type or n-type. Different nitrogen doping levels affected the diode properties differently. It demonstrated that the rectification effect of the formed pn device was clearly observed using this simple strategy. We also successfully produced this graphene lateral pn device applying a half-wave rectification circuit. The effective formed pn device can be further applied in bipolar junction transistor development. [ABSTRACT FROM AUTHOR]

The study utilized transition metal chalcogenide, molybdenum diselenide (MoSe 2 ), for application in the field of bioelectrochemical sensing. The MoSe 2 was combined with carbon nanotubes (CNTs) by chemical vapor deposition to enhance the specific surface area and improve the detection sensitivity. To further increase the contact area between the electrolyte and the electrode, photolithography techniques were employed to fabricate hive-shaped CNTs, thereby enhancing the specific surface area. Next, cholesterol oxidase (ChO x ) was coated onto the electrode material, creating a cholesterol biosensor. Cyclic voltammetry was utilized to detect the concentration of cholesterol. The experiment involved segmented testing for cholesterol concentrations ranging from 0 μ M to 10 mM. Excellent sensitivity, low detection limits, and high accuracy were achieved. In the cholesterol concentration range of 0 μ M-100 μ M, the experiment achieved the highest sensitivity of 4.44 μ A μ M⋅cm -2 . Consequently, all data indicated that ChO x /MoSe 2 /CNTs functioned as an excellent cholesterol sensor in the study., (Creative Commons Attribution license.)