Diamond and Related Materials最新文献

A multifunctional terahertz (THz) metasurface for broadband absorption and wavefront manipulation based on graphene and vanadium dioxide (VO₂) is proposed in this paper. While VO₂ is in the metallic state, a broadband absorber is obtained. The bandwidth of over 90 % absorption rate is 1.11 THz. By adjusting graphene Fermi level, absorption bandwidth dynamical tunning is realized. The modulation depth for bandwidth tuning is 64 %, and the drift of center frequency is slight. Also, an equivalent circuit model is explored to explain the absorption mechanism. While VO₂ is in the insulating state, the metasurface acts as a deflected vortex beam generator. Based on the convolutional operations, the functionalities of deflector and spiral phase plate are integrated into the proposed metasurface. Through precise phase arrangement based on the rotation angle of the metal resonator, arbitrary manipulation of transmitted vortex beams can be performed in the range of 0.75–0.85 THz. We also develop a 1D focusing metalen operating at different frequencies, which exhibits remarkable subwavelength focusing capabilities. Thus, multifuncitons including broadband absorption, beam deflection, vortex beam generation, and focusing metalen are integrated into one single metasurface successfully. It holds the great potential in diverse applications, such as optical stealth, beam generation, and holographic technique in the future.

A novel electrochemical glucose biosensor was fabricated using the casting technique of multi-walled carbon nanotubes (MWCNT)/polyaniline (PANI)/carboxymethyl chitosan (CCs) as an appropriate matrix for glucose oxidase (GOx) immobilization. The differential pulse voltammetry (DPV) study results demonstrated a wide linear range of glucose concentrations from 10 nM to 10 μM, with a limit of detection (LOD) of 1.41 μM and a sensitivity of 1791 μA mM⁻¹ cm⁻². Additionally, cyclic voltammetry (CV) data analysis yielded a heterogeneous rate constant (ks) of 0.3 s⁻¹ and an apparent Michaelis-Menten constant ($k_m^{\mathrm{app}}$) of 18 nM. Over a 30-day period, the biosensor exhibited exceptional repeatability and stability, maintaining approximately 84.58 % of its initial performance for storage stability at 4 °C and 82.13 % for functional stability. Moreover, the reproducibility, interference resistance, and overall performance of the biosensor were assessed, demonstrating its capability to accurately measure glucose levels in human serum with a relative standard deviation (RSD) of <5 %.

The aim of this research is to fabricate plane-type devices possessing straight longer axons individually and regularly arrayed for evaluating the axon behavior of neuronal cells in vitro toward the development of brain-on-chip models, utilizing diamond-like carbon (DLC) thin film patterning deposition. The DLC thin films were deposited on a polydimethylsiloxane (PDMS) plate with a plasma CVD method under four conditions, with/without stretching of and a metal mask on the plate, and the fabricated substrates were used to culture human neuroblastoma cells, SH-SY5Y, for up to 21 days. In the case of the stretched PDMS plate with the mask covered, extremely peculiar structures were created on the DLC deposited areas of the substrate, with multiple 20 μm-thick rope-like axons aligned straight at the length of millimeter-level at intervals of about 200 μm. It was found that the rope-like axons consisted of plenty of thinner axons, and were supported by the clusters of cells at both ends. It was strongly suggested that the linear wrinkle structures created by the DLC deposition played an important role in the formation of the rope-like axons. This device can be fabricated by means of not conventional lithographic techniques, but only DLC thin film deposition.

A diamond-like carbon (DLC) film was deposited using unipolar-double-pulse high-power pulsed magnetron sputtering, aimed at enhancing both film density and deposition rate. The pulse interval between the 1st and 2nd pulses, with negative polarity applied to the target, was varied from 15 to 200 μs. Temporal variations in the flux and energy of C⁺ and Ar⁺ incident to the DLC film were analyzed through energy-resolved and time-resolved mass spectrometry to clarify the ion generation process during the 1st and 2nd pulses. The contribution of ionic species in forming the DLC film through HiPIMS was clarified through mass spectrometry, Raman scattering spectroscopy, and X-ray reflectivity analyses. Reducing the pulse interval increased the deposition rate, and the film density of the DLC film was improved at a pulse interval of approximately 40 μs. Overall, the implementation of a double pulse with the appropriate pulse interval can help enhance both the film density and deposition rate.

There are various dye molecules in dye wastewater, making the degradation treatment of mixed dyes more practical. This work used ZIF-67 as a sacrificial template to prepare hollow CoS_x polyhedral as a co-catalyst to modify and improve B-doped g-C₃N₄/MoO₃ (BCM) photocatalysts for efficient degradation of MO + MB + RhB mixed dyes (the concentrations of MO and MB were both 10 mg/L and RhB was 20 mg/L). In the evaluation of the catalytic performance of mixed pollutants (100 mL) with a catalyst content of 20 mg under a simulated light source with a power of 300 W, the best degradation performance was achieved by a photocatalyst (CBCM-60) with a mass ratio of BCM to ZIF-67 of 60:1. It completely degraded MO within 20 min and degraded 87 % MB and 37 % RhB, respectively, within 200 min. In sharp contrast, the time for complete degradation of MO by BCM without CoS_x modification was extended to 40 min, and at 200 min, only 62 % of MB and 17 % of RhB could be degraded. The enhancement of the catalytic performance of CBCM is closely related to the hollow structure of CoS_x polyhedral. Firstly, the cavity structure captures incident light and undergoes multiple reflections/scattering, significantly enhancing light absorption. Secondly, the modification of CoS_x increased the specific surface area of the material, overcoming the insufficient reduction in BCM specific surface area caused by B doping. Finally, CoS_x can serve as a “high-speed channel” for electron transfer, further improving the carrier separation efficiency on the basis of Z-type heterojunctions. Therefore, the hollow CoS_x polyhedral modified B-doped g-C₃N₄/MoO₃ photocatalyst is expected to be suitable for practical industrial wastewater purification, which is also of great significance for studying how to remove mixed pollutants with two or three different molecular structures in photocatalysis.

The current investigation aims to enhance the optical and dielectric properties of poly (vinyl alcohol) (PVA)/polyethylene glycol (PEG) blended polymers via loading with copper cobaltite (CuCo₂O₄), polyaniline (PANi), and x wt% multi-walled carbon nanotubes (MWCNTs) for potential applications in optoelectronics and capacitive storage. The fabrication of PVA/PEG/CuCo₂O₄/PANi/x wt% MWCNTs blended polymers was carried out via casting and hydrothermal methods. Characterization of the blended polymer's structure and morphology was conducted using X-ray diffraction and scanning electron microscopy techniques. The impact of various fillers on the linear and nonlinear optical properties of the host blend was analyzed. The loaded blends demonstrated efficacy in blocking UVA, UVB, and UVC spectra, making them suitable absorbers for solar cells. The lowest values for direct and indirect optical band gap energy (E_g), of 5.34 eV and 4.44 eV were attained at x = 0.02. The blend with x = 0.01 displays the highest refractive index at λ = 600 nm. The optical conductivity exhibited nonmonotonically growth until peaking at x = 0.01. Analysis of chromaticity diagrams in CIE 1931 color space reveals that all blends emit blue-violet hues with slight variations in intensity. The fluorescence (FL) intensity of the doped blend is notably lower compared to the undoped counterparts. The doped blend (x = 0.03) showcases superior dielectric constants and ac conductivity values. The maximum energy density was achieved at 1 kHz for the host blend incorporating CuCo₂O₄/PANi. Overall, the observed characteristics indicate that PVA/PEG/CuCo₂O₄/PANi/x wt% MWCNTs blended polymers represent promising hybrid nanomaterials suitable for diverse applications.

Transition metal carbonitrides have been widely applied in various fields due to their excellent physical and chemical properties. In the pursuit of identifying innovative and stable crystal structures among transition metal carbonitrides, we have employed first-principles calculations to investigate the substitution of transition metal elements (Cr, Hf, Mo, Nb, Ti, V, W, Zr) for Ta within three stable crystal structure types: Ta₃C₂N, Ta₃CN₂, and Ta₄C₃N. The thermal stability, dynamic stability, and mechanical stability of these twenty-four structures were systematically studied, and nine stable new crystal structures were finally identified. Our subsequent investigations have included assessments of their structural, electrical, and mechanical properties. Our findings in mechanical properties have revealed that five compounds, Nb₃CN₂, Hf₄C₃N, Nb₄C₃N, Ti₄C₃N, and Zr₄C₃N, exhibit hardness values of 20.3 GPa, 30.0 GPa, 22.4 GPa, 28.7 GPa, and 26.2 GPa, respectively. Furthermore, our electronic property assessments have indicated that these structures exhibit metallic characteristics.

The construction of transition metal oxide with reduced graphene oxide nanosheets ha a great interest in boosting the capacitance nature of the supercapacitors. Herein, we developed the bismuth oxychloride anchored with the reduced graphene oxide nanosheets (rGO@BiOCl) for enhancing the electrochemical behaviour. The monoclinic structure of BiOCl was illustrated in XRD analysis. Also, the Raman vibrational modes are illustrating the formation of rGO anchored BiOCl nanocomposite. The morphological analysis SEM and TEM analysis show the formation of rGO nanosheet anchored with the BiOCl nanoflower. The maximum capacitance for BiOCl and rGO@BiOCl are shown as 226 and 790 F/g, respectively. However, the rGO@BiOCl electrode has attained a larger capacitance retention of 97 % even at the 2000th cycle at 5 A/g. Also, both BiOCl and rGO@BiOCl electrodes have low charge transfer resistance values of 24.72 and 14.86 Ω. In addition, the electrode was constructed as sandwiched by rGO@BiOCl (positive electrode) and rGO (negative electrode) are used for asymmetric capacitor device. From the result, rGO@BiOCl//rGO ASC shows the 194 F/g of capacitance value also it shows 24.28 Wh/kg and 1285 W/kg of energy and power density values. Moreover, the rGO@BiOCl//rGO asymmetric capacitor device shows 92.79 % cyclic stability at 8 A/g. Also, it shows the 9.25 and 8.61 Ω R_ct values for after and before stability. These findings indicate that the prepared rGO@BiOCl electrode is a suitable electrode for supercapacitor devices.

Amorphous tantalum (Ta)/carbon (C) composite films were heated with the irradiation of near-infrared lasers. The phase transformation and microstructural evolution of the films during the heating process were in situ observed by transmission electron microscopy. TaC crystals with a NaCl structure of 5–40 nm in diameter were formed in the films under laser irradiation with a density of 10 MW/m². The crystals coalesced after 160 MW/m² irradiation and the crystals diameter increased to 20–80 nm. A Ta₂C phase with a hexagonal structure was observed in addition to the TaC phase in the films after laser irradiation. This double-phase texture transformed to the single Ta₂C phase, and the diameter increased to 80–160 nm after re-irradiation up to 190 MW/m². The highest temperature at this maximum irradiation density was estimated to be 2076–2230 ± 797 K. The texture maintained after decreasing of irradiation to zero and cooling to ambient temperature, revealing that the single Ta₂C phase was stable after heating at this temperature.

To meet the growing market requirement for low-cost supercapacitor electrode materials, N/O/S self-doping hierarchical porous carbon is successfully fabricated by direct pyrolysis of platycladus orientalLeaves (POL). The obtained carbon material exhibits wide application prospects, because of simple and green-environmental technology, low-cost and satisfactory electrochemical properties, which avoided complex preparation routes and consumption of expensive chemical reagents in the traditional activation process. Under the optimum pyrolysis temperature (850 °C), the obtained POL-derived carbon (POL-850) possesses a high specific surface area (1140.2 m²g⁻¹), sheet-like hierarchical porous microstructure, and uniform ternary heteroatoms co-doping (O: 6.79 at.%; N: 3.45 at.% and S: 2.20 at.%). As an electrode material for supercapacitor, the specific capacitance of the POL-850 reaches 224.4 Fg⁻¹ of 0.5 Ag⁻¹and 156.0 Fg⁻¹ at 30 Ag⁻¹, revealing excellent rate performance. The capacitance retention maintains 96.3 % after 10,000 consecutive charge-discharge cycles at 20 Ag⁻¹, demonstrating superior cycling stability. Additionally, the assembled carbon-based symmetric supercapacitor device delivers a satisfied energy density of 11.0 Wh kg⁻¹ with the power density of 65 W kg⁻¹ and ultralong cycle-lifetime with 95.65 % capacitance retention after 10,000 charge/discharge cycles, while the Coulombic efficiency is retaining up to approximately 100 %. This work provides an easy and cost-effective way to rapidly prepare N/O/S co-doping hierarchical porous carbon for supercapacitors, which is very suitable for large-scale production.