Sulfur and nitrogen dual-doped graphene (SNG) was prepared by atmospheric thermal plasma, and its synthesis mechanism was investigated. The morphology and doping concentration were characterized and analyzed. Reactive force field molecular dynamics (ReaxFF) simulations were used to visualize the graphene growth process. Doping concentrations were markedly enhanced in dual-doped (S and N) graphene compared with single-doped (S or N) graphene. Reaction pathway analysis showed that highly reactive sulfur readily bound to polycyclic aromatic hydrocarbons (PAHs) and carried less reactive nitrogen into the graphene framework. The effects of the hydrogen-to-carbon ratio were systematically examined by comparing methane, ethylene, and acetylene feedstocks, and a higher hydrogen-to-carbon ratio was found to significantly improve the morphology and doping level of SNG. When methane was used as the carbon source, the atomic percentages of nitrogen and sulfur reached 4.81% and 10.83%, respectively. These findings contributed to a deeper understanding of the design and preparation of highly doped graphene materials.
P-type nickel oxide (NiOx) films with adjustable properties are essential for advanced optoelectronics and photovoltaics. We show that the power of ALD H2O plasma (50-200 W) serves as a key parameter for controlling structural, optical, electrical, and electronic properties of NiOx films grown from Ni(acac)(2) precursor. Structurally, all obtained films had nano-crystalline cubic NiO phase; a secondary Ni3C phase emerged only for 200 W plasma, producing large crystallites (similar to 10-13 nm) and surface roughness (0.85-2.39 nm). Visible light transmittance varied with plasma power from >80% (50 W) to similar to 60% (200 W) due to increased scattering on incorporated defects. All films had p-type conductivity (similar to 10(-4) S/cm). The 200 W sample featured the highest mobility (10.07 cm(2)/V & centerdot;s) and conductivity (8.91 & times; 10(-4) S/cm). XPS analysis confirmed formation of non-stoichiometric NiOx with plasma-dependent defect configurations. The CNi peak appeared only at high plasma power. Electronic structure analysis confirmed that plasma power can be used for the efficient fine-tuning of band gap (3.35-3.54 eV), work function (5.17-5.70 eV), and the position of valence band maximum (-0.73 to -0.35 eV relative to the Fermi level E-F). The films deposited with 50 W plasma featured a promising parameter balance for hole transport layers: high transparency (>80%), low roughness (0.85 nm), good band alignment (E-F - 0.73 eV) and conductivity (3.45 & times; 10(-4) S/cm). These results establish the H2O plasma power as a versatile parameter for defect engineering and control of band alignment in NiOx, capable of producing good-quality hole transport layers for perovskite solar cells and other transparent optoelectronic devices.
Triple quantum wire (TQW) nanostructures represent a promising platform for tunable nanoscale electronic and optoelectronic devices, yet their donor impurity properties remain largely unexplored. In this work, we investigate a triple GaAs quantum wire system separated by Ga1_ xAlxAs barriers. Using the finite element method within the effective mass approximation, we calculate the donor binding energy and electronic polarizability. The donor binding energy exhibits a characteristic triple-peak profile, reflecting the spatial distribution of confined states and the interplay between quantum confinement and inter-wire coupling across the three wires. We further show that the binding energy is strongly influenced by inter-wire coupling, impurity position, alloy composition, and externally applied electric fields. Moreover, the electronic polarizability can be efficiently tuned through the quantum wire width, inter-wire coupling, alloy composition, and external electric fields, with a maximum response observed at intermediate wire widths where confinement and carrier delocalisation compete. These findings demonstrate that careful impurity positioning and structural design provide effective routes for controlling the donor binding energy and polarizability, offering valuable insights for the development of advanced nanoscale electronic and optoelectronic devices.
In this work, new multiferroic nanocomposites based on (1-x) Ni0.5Co0.5Fe2O4 + (x) Ba0.85Ca0.15Zr0.1Ti0.9O3 (where x = 0.0,0.20, 0.40,0.60,0.80 and 1) have been synthesized by conventional solid state reaction route. Structural studies have been done by XRD and Rietveld analysis technique. Energy gaps were determined using UV-Vis spectrophotometer, and values for ferrite NCFO is 1.17 eV, BCZT pure phase is 3.01 eV, whereas energy gap values vary from 1.66 eV to 2.24 eV in the case of composites. Also, the presence of ferrite T2g, A1g, Eg vibrational modes and perovskite A1(TO), E(TO) vibrational modes were confirmed through Raman spectroscopy and proved strong interfacial coupling. Scanning electron microscopy (SEM) analysis has been carried out for determining morphological characteristics of the synthesized samples. Sample N60B40 possesses highest coercivity of 470.3 Oe, whereas N20B80 exhibits minimum coercivity of 431.4 Oe. Other samples possess moderate values, such as 453.3 Oe forN80B20 and N60B40 470.3 Oe. Moreover, the dielectric constant decreases and remains constant while increasing the frequency. The N80B20 composite was observed to have the maximum magnetodielectric constant of 8.30%, which is significant at low frequency with corresponding magnetodielectric loss variation, the results revealed a significant magnetodielectric coupling effect.
We developed a highly efficient and stable CdS loaded sepiolite catalyst, CdS@SEP, with a one-step calcination process, under mild conditions (200 degrees C, 1 h)-distinct from conventional high-temperature processes-with parameters optimized by orthogonal design (L-16 4(5)). XRD and TEM results confirmed that CdS was loaded on fibrous sepiolite, forming a composite that facilitated charge separation. The prepared catalyst could not only enhance the visible light absorption, but also reduce the charge transfer resistance. The CdS@SEP achieved >97% Rhodamine B removal via synergistic adsorption-photocatalysis, with the adsorption process following pseudo-second-order kinetics and the Freundlich model, and the photocatalytic degradation process following pseudo-first-order kinetics. The CdS@SEP catalyst exhibited excellent pH stability (3-9) and maintained 86.22% of its photocatalytic activity after five cycles. Additionally, the Cd2+ leaching analysis demonstrated the environmental safety of the catalyst. TOC analysis and seed germination test jointly indicated the reduction of contaminant toxicity. Trapping and ESR results identified holes (h(+)), superoxide radical anions (& centerdot;O-2(-)), singlet oxygen (O-1(2)) as the primary active substances. Band edge analysis (ECB = -0.59 V, EVB = +1.69 V) thermodynamically supported the generation of & centerdot;O-2(-)/O-1(2) over hydroxyl radical (& centerdot;OH). This work offers a low-energy strategy for designing clay-based heterostructured photocatalysts with selective ROS for wastewater remediation.
