Bulletin of Materials Science最新文献

This study is aimed to have an understanding of the formation of silicon vacancy (SiV) colour centres in diamond during thin film growth of diamond in microwave plasma CVD reactor. The study focusses on different sources of silicon impurities in the chamber and the possibility of controlling the formation of SiV during growth for various applications. Diamond thin films were grown on different substrates and their photoluminescence (PL) spectra were analysed to understand the role of substrate material and residual silicon in the chamber for the formation of SiVs. The predominant contribution to SiV formation was found to be the residual silicon in the chamber originating from the quartz components exposed to the plasma. In the films grown on silicon substrate, there is also substrate contribution to the PL signal. Controlling the formation of SiVs in polycrystalline diamond can pave the way to optically integrate SiVs to different photonic structures.

This study introduces a method for producing environmentally friendly peelable film using prevulcanized rubber latex, offering a simple and cost-effective solution capable of covering complex shapes. The synthesis investigation explores the relationship between conventional rubber formulations and the film’s performance, highlighting the significance of selecting appropriate chemicals to improve functionality. Key considerations for selecting the latex compound formulation include the solution's properties, particularly focussing on flow behaviour and coating time, as well as the mechanical properties, fire resistance, peel ability and durability of the resulting film under challenging conditions. The primary investigation into the impact of the zinc diethyldithiocarbamate : sulphur (ZDEC : S) ratio on crosslink density provides insight into rheological and mechanical properties. Furthermore, the addition of phenol, 4-methyl-, reaction products with dicyclopentadiene and isobutene (CPL) as an antioxidant improves heat resistance and oxygen tolerance. The remarkable versatility of peelable film allows for its application through various methods, including sagging (1–10 s^–1), painting and spraying (10–100 s^–1), effectively protecting against dust, scratches and temperatures exceeding 200°C. Particularly noteworthy are its low peel force of 0.139 N, 44 mm removal path and 2-month service life. The findings from testing the crucial properties of the manufactured films, which meets industrial standards, indicate a pathway to produce environmentally sustainable products, with a strong potential for further advancement towards commercial production.

Owing to the increasing demands of high-density data storage double-halide perovskite-based resistive random access memory (RRAM) have recently emerged as a promising candidate in the forefront of next-generation optoelectronic memory applications. The ionic motion-based quick switching is the key feature of this kind of material, which plays a significant role in resistive switching (RS) applications. Recently, lead-free tin-based double-halide perovskites have been considered as favourable material due to their superior stability, functionality and eco-friendly nature. Here, we report the synthesis of cesium tin (IV) iodide (Cs₂SnI₆) perovskites. X-ray diffraction (XRD) pattern of the as-synthesized perovskite confirms the formation of Cs₂SnI₆ material. The crystallographic data corroborate the formation of a pure cubic phase, free of any other phase at room temperature. We also studied optical properties of the sample by using the ultraviolet–visible (UV) spectra and photoluminescence (PL) spectra. A broadband at around 580 nm is observed in the UV−Vis absorption spectra. The optical band gap of the sample is found to be 1.68 eV. Cs₂SnI₆ perovskite exhibited intense PL emission at ~540 nm. In this work, to fabricate a flexible Al/Cs₂SnI₆/ITO-PET memory device, we used Cs₂SnI₆ film as a switching layer and the device exhibits bipolar RS characteristics.

Increasing environmental issues have emerged due to various pharmaceutical wastes. These wastes are difficult to remove by treatment due to their continuous consumption and long-term persistence. We have synthesized two different shapes of zinc oxide (ZnO) nanoparticles as catalysts—nanorod (ZnO–NR) and oval-shape (ZnO–OS). A comparative performance of these two catalyst shapes on photocatalytic degradation of rifampicin (RIF) in water—a first-line anti-tuberculosis drug, was carried out. ZnO–NR showed three times higher normalized first-order degradation rate constant of RIF under UV light than that with ZnO–OS. This is due to: (i) specific surface area and specific pore volume of ZnO–NR being 25 and six times higher, respectively, than ZnO–OS; (ii) oxygen vacancy in ZnO–NR being 1.7 times higher than ZnO–OS; (iii) slightly lower band gap energy in ZnO–NR than ZnO–OS, adding to carrier concentration; and (iv) ZnO–NR additionally showing 12.4% chemisorbed oxygen also. Towards RIF degradation, ZnO–NR shows a much improved synergistic effect than ZnO–OS under UV light, as ZnO–NR under UV light is found to give 2.7 times higher degradation than when the catalyst and UV act independently and hence only additively. Therefore, this study is helpful in tuning the shape-dependent chemical reactivity of nanoparticles in water treatment.

At present, selective and accurate determination of hydrogen peroxide (H₂O₂) and glucose has become essential for routine diagnosis. The present work demonstrates the hydrothermal synthesis of NiO nanosheet (NS)–MoS₂-based composite system for non-enzymatic electrochemical detection of H₂O₂ and glucose. To understand the structure, morphology and elemental constituents of the prepared composite system, various characterization techniques were employed, namely XRD, FTIR, FESEM, TEM and EDX. Redox activity and charge transfer process of the NiO–MoS₂-based sensor electrode towards H₂O₂ and glucose were realized via using electrochemical techniques: cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry. To be mentioned, limit of detection (LOD) and sensitivity for detection of H₂O₂ are calculated to be 3 µM and 3925 µA mM⁻¹ cm⁻², respectively, under the linear range of 5–455 µM in 0.1 M PBS solution. Similarly, the LOD and sensitivity for sensing glucose is estimated to be 3.53 µM and 1880 µA mM⁻¹ cm⁻², respectively, under the linear range of 5–370 µM in 0.1 M NaOH solution. The cost-effective fabricated sensor exhibited good stability with a high selectivity towards the specific analytes only.

This article investigates the effect of morphology on the thermoelectric properties of nanostructured zinc oxide. Three different samples of nanostructured zinc oxide, named ZnO, ZnO triethanol amine (TEA) and ZnO Calc., were synthesized. ZnO and ZnO TEA samples were synthesized by the chemical precipitation method, while ZnO Calc. sample was prepared by the direct calcination method. The FESEM analysis revealed that ZnO and ZnO Calc. samples have flakes and nanorod-like morphology, respectively, while ZnO TEA has a mixed hexagonal and irregularly shaped morphology. The Rietveld refinement of X-ray diffraction data confirmed that all the prepared samples have a hexagonal wurtzite phase of ZnO with space group P6₃mc. The energy-dispersive X-ray spectroscopy confirmed the presence of zinc and oxygen in all the synthesized samples. The electrical resistivity and Seebeck coefficient were recorded in the temperature range of 300–950 K. The negative values of the Seebeck coefficient revealed the n-type nature of all the samples. The increase in electrical resistivity with the increase in temperature confirmed that all three prepared ZnO samples show metallic behaviour. The highest Seebeck coefficient of –245 μV K^–1 was attained by ZnO nanorods at 950 K, while the lowest Seebeck coefficient of –212 μV K^–1 was obtained for ZnO TEA at 950 K. The highest thermoelectric power factor of 2.11 (times , {10}^{-3}) W m^–1 K^–2 was attained by the ZnO Calc. sample at 950 K. The results indicate that the synthesized ZnO Calc. sample with nanorod-like morphology has better thermoelectric performance as compared to flakes and platelets-like morphology.

Inspired by NG/TiO₂ composite reinforcing particles in the Ni–P matrix, an electrochemically assisted electroless deposition method was used to deposit Ni–P–TiO₂–NG composite coatings on steel substrates in order to enhance their electrochemical and photocatalytic properties. The effects of current density on the microstructure, surface morphology and phase composition of the coatings were investigated. Statistical analysis based on multifractal formalism shows that the uniformity of the height distribution shows an increasing and then a decreasing trend as the current density increases. The results show that the average hardness reached a maximum value of 966 H_V0.1 for the optimum coating obtained at a current density of 4 A dm^–2, the corrosion current reached a minimum value of 2.041 × 10^–5 A cm^–2, with a maximum corrosion potential of –0.281 V vs. SCE. These improvements can be attributed to high phosphorus Ni–P composite coatings with smooth and dense morphology, TiO₂/NG nanocomposite impermeability and excellent mechanical properties. In addition, the photocatalytic activity of the Ni–P–TiO₂–NG coating gradually increases with increasing current density.

Owing to their characteristics like fast charge–discharge rate, very long life, simple geometry and eco-friendly nature, supercapacitor is an emerging technology to fulfil the present and future requirements of the energy. The performance of a supercapacitor is derived from the composition and morphology of the electrode. 2D materials possess various excellent structural properties like surface area, flexibility in the atomic scale dimension and mechanical strength with high electrical conductivity. This makes them an entrusted material to be used as an electrode material. The teaming of 2D materials and layered transition metal dichalcogenides have been of great interest for electrode materials. In this study, the reduction of graphene oxide is done by an environment-friendly synthesis method using cow urine, and then, synthesizing the reduced graphene oxide (rGO) and transition metal dichalcogenides (TMD) composite using the refluxing method. The modified pencil graphite electrode (PGE) was functionalized using the above composite and the performance is comparable to that of glassy carbon electrode. Our main motive was to develop a low-cost, sustainable and highly effective MoS₂–rGO/PGE, which is completely based on an environment and eco-friendly method using natural precursors. The prepared MoS₂–rGO nanocomposite was characterized by XRD, SEM and EDX, which revealed the formation as well as its morphological scenario. MoS₂–rGO/PGE is explored as electrode material by electrochemical characterization with the 3-electrode system through cyclic voltammetry and electrochemical impedance spectroscopy, which exhibit maximum specific capacitance with good cycle stability.

In this study, Cu- and Zn-doped SnO₂ nanoparticles (NPs) were synthesized by using the solvothermal method. The synthesized NPs were explored to check their supercapacitor, photovoltaic and magnetic properties. The Cu-doped SnO₂ NPs showed a high specific capacitance of 386 F g⁻¹ at 20 mV s⁻¹ in 1 M KOH electrolyte and remarkable catalytic performance as a counter electrode (CE) for dye-sensitized solar cells (DSSCs), achieving a power conversion efficiency (PCE) of 10.70%, comparable to that of Pt CE. Moreover, Cu-doped SnO₂ NPs displayed the highest room-temperature ferromagnetism, indicating their potential for magnetic device applications. Our results suggest that doped SnO₂ NPs are promising candidates for multifunctional nanomaterials in energy and information technologies.

Garnet-type oxide materials show high Li-ion conductivity and may be used as solid-state electrolytes in lithium-ion batteries to address safety concerns. In this study, Nb-doped Li₇Nd_2.8Ca_0.2Zr_1.8Nb_0.2O₁₂ (LNdCZNbO) and Ta-doped Li₇Nd_2.8Ca_0.2Zr_1.8Ta_0.2O₁₂ (LNdCZTaO) garnet-type compositions were prepared to examine the impact of Nb- and Ta-doping on ionic conductivity of Li₇Nd₃Zr₂O₁₂ (LNdZO). XRD patterns showed the crystallization of major phase of these garnet-structured oxides in tetragonal symmetry. Impedance measurements were recorded from room temperature to 450°C using a Novocontrol make impedance analyzer (Alpha-A high-performance frequency analyzer) in the frequency range of 1 Hz–40 MHz. The maximum total conductivity of parent composition LNdZO was 5.12 × 10⁻⁵ S cm⁻¹ at 25°C. The compositions of LNdCZNbO and LNdCZTaO showed conductivity 7.05 × 10⁻⁴ and 8.23 × 10⁻⁴ S cm⁻¹, respectively, at 25°C. On higher temperature of 350°C, these doped compositions, LNdCZNbO and LNdCZTaO, showed enhanced conductivity of 3.30 × 10⁻³ and 2.63 × 10⁻³ S cm⁻¹, respectively, as compared to the parent LNdZO composition’s conductivity of 4.42 × 10⁻⁴ S cm⁻¹. Analysis of the Cole–Cole plots fitting showed the nature of Li ionic conduction and the existence of bulk and grain boundary impedances in these compositions. The activation energy was found to be higher for the compositions of LNdCZNbO (0.18 ± 0.01 eV) and LNdCZTaO (0.17 ± 0.01 eV) in comparison with the activation energy of undoped composition Li₇Nd₃Zr₂O₁₂ (0.14 ± 0.00 eV) due to the change in garnet lattice by doping of Ca and Nb/Ta.