Bulletin of Materials Science最新文献

Reviews of renewable energy are being prompted more frequently by economic challenges and climate change resulting from global warming. Solar cells are commonly regarded as renewable energy sources among energy-producing technologies. The majority of the world’s photovoltaic (PV) fabrication capacity is embraced by technologies based on silicon heterojunction (SHJ) solar cells. In mass production, the conversion efficiency of the SHJ solar cell has surpassed 26%. The main challenges to the industrial-scale implementation of SHJ solar cells are now carrier recombination, which includes contact recombination (at the metal-semiconductor), surface/interface recombination (at c-Si surfaces), and bulk recombination (within c-Si), which is typically minimal in high-quality wafers. To minimize recombination and improve the performance of SHJ solar cells, light utilization, optical design, and material parameters (the functional layers) must be optimized. The latest developments in SHJ solar cells are reviewed. We review the various factors that can influence the solar cell gain and loss mechanisms, with a particular focus on the Interlayer and capping layer that affect the overall performance of the SHJ solar cell. We examine the current limitations and potential solutions to the industrialization of SHJ technology, most of which are currently being explored in the industrial field. The systematic dependability and simplicity are reviewed with an eye on their use in performance improvement.

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The environmental toll of petroleum-based plastics, with tensile strengths of 10–20 MPa, includes pollution, greenhouse gas emissions, and crude oil depletion, driving the need for sustainable alternatives. This study established linseed oil (LO), a renewable source rich in polyunsaturated fatty acids, as an exceptional feedstock for polyurethane (PU) biomaterials, surpassing traditional materials. An optimized synthesis route involving epoxidation, ring-opening, and polyaddition with a suitable linker is the conventional route for PU materials. In the current work, hexamethylene diisocyanate (HDI) as a linker and cellulose nanofibers (CNF) as a sustainable filler material were used at an optimized ratio to produce LO-derived polyurethane (LPU) and CNF-reinforced LPU (LPU-CNF) composite sheets. These achieved a tensile strength of 18.95 MPa and a glass transition temperature (Tg) of 220–240°C, outperforming many fossils fuel-derived PUs (T_g 150–200°C). Spectroscopic (FTIR, XPS) and crystallographic (XRD) analyses confirmed their molecular structure and enhanced crystallinity. The high unsaturation of LO enabled robust crosslinking, while CNF reinforcement boosted mechanical and thermal properties, validated by tensile testing, TGA, and DSC. Computational density functional theory (DFT) studies underscored the thermodynamic favorability of the synthesis, reinforcing the stability of LPU-CNF. These biomaterials hold potential for packaging, foams, coatings, adhesives, and biocomposites, supporting the transition to eco-friendly, high-performance alternatives to petroleum-based plastics.

For the first time, a graphite sheet supported palladium (Pd) and ruthenium (Ru) composite catalyst (denoted as Pd_xRu_y/GS) (catalyst a) for alkaline hydrogen evolution reaction (HER) is synthesized using an air calcination approach, in which RuO₂·3H₂O, PdO and graphite are employed as the starting materials. Of note, the atomic ratio of Ru in RuO₂·3H₂O to Pd in PdO is 7:1, and the calcination temperature and the calcination time are respectively 800°C and 1 h. For comparison, the catalyst prepared using RuO₂·3H₂O and graphite is denoted as Ru/GS (catalyst b), and the catalyst synthesized employing PdO and graphite is denoted as Pd/GS (catalyst c). As analysed by XRD (X-ray diffraction) and XPS (X-ray photoelectron spectroscopy), RuO₂, metallic Ru, PdO, metallic Pd and graphite with a higher crystallinity are indicated to be the main substances of catalyst a. As demonstrated by linear sweep voltammetry (LSV) curves, the over-potential required for achieving –10 mA cm⁻² on catalyst a is about 136 mV, a value being much smaller than that of catalyst b (180 mV) and c (600 mV). The Tafel slope of catalyst a for HER is about 107.4 mV dec⁻¹, much smaller than that of catalyst b (142.8 mV dec⁻¹) and c (172.4 mV dec⁻¹). More importantly, in the 10 h-CA test, the average HER current densities measured at −1.53 V vs. Hg/HgO in 1M KOH were, respectively, about 350 mA cm⁻², 279 mA cm⁻² and 3.3 mA cm⁻² on catalyst a, b and c. After systematic characterization and testing, the greatly decreased charge transfer resistance and the relatively higher electrochemical surface area (ECSA) value are considered to be the main reasons why catalyst a has excellent HER electrocatalytic ability. A very simple method to prepare a graphite sheet-supported Pd and Ru composite HER catalyst has been demonstrated in this work. This method, due to the rather simple preparation process and the satisfied HER performance, is very meaningful to the further exploration of alkaline HER catalyst.

Ferroelectric thin films hold potential for non-volatile memory applications due to their inherent polarization. Barium titanate (BaTiO₃) is noted for its high dielectric constant and low loss. This work reports the modulation of resistive switching in BaTiO₃ under dark and illuminated conditions. A polycrystalline thin film of pristine BaTiO₃ (BTO) was fabricated on an FTO substrate using the spin-coating technique. The Al/BTO/FTO device illustrates a tetragonal phase with a film thickness of 300 nm. The energy band gap of BTO is found to be 3.6 eV. The current–voltage (I-V) data shows the resistive switching behavior of the BTO thin film under dark and light conditions, making it suitable for future opto-memristor devices. This Al/BTO/FTO device was tested for endurance and retention performance with and without illumination; it shows stability up to 500 cycles and 5000 s, respectively. The Al/BTO/FTO device can be useful in non-volatile resistive random-access memory (ReRAM).

The development of eco-friendly additives for electroplating is essential for advancing sustainable surface engineering. This study reports the synthesis of a novel organic brightener via the condensation of vanillin and L-glutamic acid, both naturally occurring and biodegradable compounds. The synthesized brightener was incorporated into a zinc–nickel (Zn–Ni) electroplating bath to evaluate its effect on coatings deposited on mild steel substrates. The coatings were characterized using field emission scanning electron microscopy (FESEM), reflectance measurements, X-ray diffraction (XRD), and electrochemical impedance spectroscopy (EIS). The results demonstrated that the addition of the brightener significantly reduced surface roughness and increased coating brightness to above 80%, yielding smoother and more uniform surfaces. Enhanced corrosion resistance was also observed, with a corrosion rate of 9.172 × 10⁻⁶ g h⁻¹ compared to 1.135 × 10⁻⁵ g h⁻¹ for coatings obtained from an additive-free bath. Furthermore, the presence of the brightener promoted grain refinement, reducing the average crystallite size from 80.4 to 52.3 nm, and markedly improved surface morphology. Owing to its bio-based origin and low toxicity, the synthesized additive represents a sustainable alternative to conventional synthetic brighteners. Overall, this work supports the advancement of green electroplating technologies and demonstrates a viable approach for producing high-performance, environmentally responsible alloy coatings.

Graphical Abstract

Biodegradable alloys in orthopedic implant applications avoid revision surgeries; these alloys need mechanical properties akin to human bones and desirable degradation rates. This study investigates how Zn and Ca content influences the mechanical and degradation properties of as-cast Mg–Zn–Ca alloys. The study involved six alloys with two different Zn contents (3 and 5 wt.%), each having three different Ca contents (0, 0.3, and 0.5 wt.%). This manuscript describes the structural and mechanical characteristics and in vitro degradation (in simulated body fluid) of these alloys. The ultimate tensile strength and elongation of each 0.3 wt.% Ca alloy are greater than those of the corresponding 0.5 wt.% Ca alloy (MZC33 > MZC35 and MZC53 > MZC55; the first digit represents the Zn wt.% while the second digit denotes 10 times the Ca wt.%). The observed changes are explained on the basis of phase composition, microstructural changes, secondary phase distributions, etc. The degradation of the alloys with 3 wt.% Zn increased with Ca content in potentiodynamic investigations. Amongst the alloys with 5 wt.% Zn, the MZC53 alloy (5 wt.% Zn and 0.3 wt.% Ca) had the lowest corrosion rate; these alloys, in the order of increasing corrosion rate, are: MZC53 < MZC50 < MZC55. The degradation in the immersion studies is higher for each 0.3 wt.% Ca alloy than for the corresponding (same Zn content) 0.5 wt.% Ca alloy (MZC33 > MZC35 and MZC53 > MZC55). Discrepancies in the long-term immersion studies vis-à-vis the potentiodynamic polarization studies are elucidated in terms of time, ion accumulation, and associated reactions. The authors suggest post-processing of the alloys to enhance the properties to suit orthopedic implant requirements.

The γ-phase of the silver iodide, γ-AgI, is a metastable polymorph of AgI that crystallizes into a zincblende structure, which exhibits n-type semiconducting behaviour and allows Ag⁺ ionic transport by interstitials. On the other hand, γ-CuI is a p-type semiconductor, isostructural to γ-AgI, with transport governed by the formation of Cu⁺ Frenkel-type defects. This prompted us to investigate the shift in electrical transport with the substitution of Ag by Cu in γ-AgI. Towards this objective, we report the computational study on the 1 × 1 × 1 unit cell of γ-Ag_1–xCu_xI (x = 0.00–1.00) using the density functional theory by employing the hybrid HSE06 functional within the full-potential linearized augmented plane wave (FP-LAPW) method. The optimized lattice parameters and bulk modulus were found to vary linearly with increasing Cu content, whereas the bandgap exhibits a nonlinear dependence on Cu concentration. The computed density of states and band structure further elucidate the electronic transitions induced by Cu substitution.

Nano-structured Ni thin films were deposited on silicon substrates using D.C. magnetron sputtering to observe the changes in crystallite size, lattice strain, thickness, roughness, density, and magnetic properties under various growth conditions. Grazing-incidence X-ray diffraction measurements were performed on the films at different incident angles for each film. The crystallite sizes, lattice strain, and dislocation density for each film at different penetration depths were calculated and analyzed. An increase in the crystallite size and a decrease in the strain with substrate heating and post-deposition annealing were observed to different extents. Crystallite sizes were also seen to increase with penetration depth. The thicknesses of the films were measured using X-Ray Reflectivity. The magnetic properties were investigated using SQUID analysis. The structural and magnetic properties of the films were correlated.

Interdiffusion studies and the formation of new phases in multilayer films have attracted interest both as a method for synthesizing new intermetallic compounds and in assessing the stability of layered structures used in microelectronics. The effect of low-temperature annealing on the state of Co/Pd multilayer film nanostructures with a cobalt layer thickness of 10 nm and palladium thicknesses of 0.5, 1, 2, 3 and 4 nm was studied using the ferromagnetic resonance method. The Co(Pd) solid solution phase formed as a result of annealing affects the ferromagnetic resonance field in a qualitatively different way, depending on the thickness of the initial Pd layer. In films with a Pd layer thickness greater than 2 nm, the resonance field increases, while at smaller thicknesses it decreases. An estimate of the activation energy of the process leading to the formation of a solid solution, 38 kJ mol⁻¹, indicates the diffusion character of the atomic transfer.