Bulletin of Materials Science最新文献

Double perovskite materials present significant advantages in terms of stability, environmental safety, tunability, charge dynamics and efficiency, making them a promising avenue for future solar cell technologies. In the present study, the numerical simulation for the photovoltaic performance of lead-free halide double perovskites (HDPs) X₂AgBiI₆ (where X = Rb, K) estimated using the one-dimensional solar cell capacitance simulator (SCAPS-1D) package is discussed in detail. A range of electron transport layers (ETLs) such as zinc oxide (ZnO), titanium oxide (TiO₂), fullerene (C₆₀), indium gallium zinc oxide (IGZO), tin oxide (SnO₂) and [6,6]-phenyl-C₆₁-butyric-acid methyl ester was varied to identify the best fit. Similarly, the hole transport layers (HTLs), namely cuprous oxide (Cu₂O), cuprous thiocyanate (CuSCN), copper antimony sulphide (CuSbS₂), nickel oxide (NiO), poly(3-hexylthiophene), PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulphonate), spiro-MeOTAD (2,2′,7,7′-tetrakis[N,N-di (4-methoxyphenyl)amino]-9,9′-spirobifluorene), CuI (copper iodide), CuO (cupric oxide), V₂O₅ (vanadium pentoxide), CBTS (copper-barium-tin-sulphide) and CFTS (copper ferrous tin sulphide), respectively, were extensively studied in solar device configuration. The influence of various physical parameters, such as different layers, thickness of ETL and HTL and temperature, was investigated. The performance of the proposed HDPs improved with increases in layer thickness and decreases in temperature. The proposed studies may pave the way towards more stable and efficient HDPs for futuristic photovoltaics.

The investigation on obtaining composite material based on Ni–Ti–Al system has been carried out in this article. Experimental samples were obtained using two methods: pressing and additive forming. Samples of nickel, titanium and aluminium powders were pressed under a pressure of 4 tons in order to study the physical and mechanical properties of the obtained materials. The concentrations of titanium and aluminium varied from 10 to 20 wt%. The physical and mechanical characteristics of the experimental samples were studied; in particular, the density, Rockwell hardness, Vickers microhardness and flexural strength. It was shown that at a concentration of 20% titanium and aluminium, high values of physical and mechanical properties were obtained, with the bending strength of 810 MPa. In this study, a screw extruder was developed, which enabled the production of 3D-printed products with a small proportion of polymer binder. Using the FDM (fused deposition modelling) method, experimental samples were obtained from a mixture of Ni 80% + (Al + Ti) 20% and its properties were determined. The phase composition of the obtained samples was studied, revealing that the main phases formed during sintering are intermetallic compounds, specifically Ni₃Al and Ni₃ (Al, Ti).

Producing multi-layer soundproofing materials by combining materials with different properties is a widely used method. The production of these types of structures utilizes the superior properties of each layer contained within the structure. This study addresses the acoustic performance of nonwoven surface structures fabricated in different thicknesses and densities using chicken feather fibres in different constructions. An impedance tube was used to determine the sound absorption and sound transmission loss values of two-layer structures of different densities and thicknesses. The results show that the influence of the layer in front or behind on the values of sound transmission losses is very limited in two-layer structures with varying densities and thicknesses. However, for the degree of sound absorption, it is important which layer is closer to the sound source. These findings are based on an analysis of multifactorial experimental data. Accordingly, the sound absorption coefficients and sound transmission loss values of all two-layer structures decrease slightly with increasing sound frequency in the frequency range of 63–200 Hz and then increase. The low-density layer on the front of the combined structure ensures better sound absorption at low and medium frequencies. As the density of the front layer increases, its ability to absorb sound decreases. It has been found that the sound absorption capacity of structures with a low density on the front and a thick layer on the back is highest.

This study investigates the effects of doping MgH₂ with rhodium (Rh) on hydrogen desorption activation energy, utilizing kinetic Monte Carlo simulations to elucidate the underlying mechanisms. The introduction of this transition metal significantly influences the desorption kinetics, with activation energies measured at 128.2 kJ mol^–1 for 6.25 wt% Rh and 136.3 kJ mol^–1 for 3.125 wt% Rh. The kinetic Monte Carlo simulations provide detailed isothermal Temperature Programmed Desorption profiles for each doped system, revealing that 6.25 wt% Rh doping notably reduces the activation energy and time required for hydrogen desorbed, thereby enhancing the desorption process. Rh doping presents intermediate effects, offering a nuanced understanding of how transition metal doping can be tailored to optimize hydrogen storage in MgH₂. These findings contribute valuable insights into the design of advanced hydrogen storage materials, making this study a significant addition to the field.

CuCr₂O₄ and Fe-substituted CuCr₂O₄ nanoparticles were synthesized via the sol–gel method, and their structural, morphological and optical/electrical properties were investigated using X-ray diffraction (XRD) and terahertz spectroscopy. XRD analysis revealed that the parent compound exhibits a tetragonal spinel phase, while Fe substitution induces a phase transition towards the cubic spinel structure. Dynamic light scattering measurements indicated a decrease in average particle size with increasing Fe content. Additionally, zeta potential measurements showed a reduction in surface charge upon Fe substitution, suggesting changes in colloidal stability or surface chemistry. Terahertz spectroscopy revealed that increasing Fe content led to a progressive increase in absorption coefficient, refractive index and dielectric constant across the series. As a result, the electrical conductivity of the nanoparticles increased with Fe substitution, likely due to enhanced charge carrier mobility or polaron hopping facilitated by the Fe dopants.

Two new hybrid compounds were synthesized by combining potassium N–(4-methylphenylsulfonyl)dithiocarbimate (DCBI) with layered zinc hydroxy salts: zinc hydroxynitrate (ZHN) and zinc hydroxyacetate (ZHA), using a coprecipitation method. The materials were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), confirming the incorporation of the organic anion into the layered structure. DCBI and the host layers interact mainly through the CS₂ group. The compounds were evaluated as accelerators in the vulcanization of rubber and compared to the commercial accelerator ZEDC. The synthesized materials led to slower vulcanization reactions and vulcanizates with higher elongation at break and lower tear resistance. These features suggest that the materials may be suitable for applications that require greater flexibility and improved safety, presenting a promising alternative to conventional amine-based accelerators.

Graphical abstract

The vulcanization process was conducted with the interlayer materials synthesized in this work.

Over the last decade, graphene's exceptional properties have revolutionized diverse fields with applications spanning electronics, materials science, energy storage, gas sensing and biotechnology (Castro Neto et al [1]). Graphene oxide (GO), derived from graphene has gained significant attention in the field of gas sensing due to its exceptional electrical, chemical and mechanical properties (Ma et al [2], Klechikov et al [3]). Modified Hummer’s method of GO synthesis is a well-known protocol wherein sonication, a powerful dispersion technique, is employed to exfoliate and functionalize GO sheets. Sonication provides the necessary energy to facilitate separation of bulk graphite oxide into thin, single- or few-layered GO nanosheets (Bera et al [4]). In this study, six GO samples synthesized at varying sonication times (5–120 min) have been investigated for H₂ and SO₂ gas sensing and their response characteristics were analyzed. The application of ultrasonic energy, leading to shear forces, reducing the lateral size of GO flakes, thus producing more uniform nanosheets, is clearly discernible. Characterizations including XRD, Raman, FTIR, TEM and UV-vis are shown to support the control influenced by sonication vis-à-vis reduction of particle size and control of flake morphology. Maximum gas sensing response characteristics were observed for GO sample that has been sonicated for 90 min. A fragmentation of the GO nanosheet along the a-axis is clearly discernible for sonication times greater than 60 minutes. It facilitates enhancement of the gas sensing response characteristics for both the gases.

The development of advanced alloys materials with tailored mechanical properties is essential for industries such as aerospace engineering. Conversely, the ability to design custom chemical compositions based on desired properties is fundamental to many industrial applications. In this research, an artificial neural network (ANN) and generative adversarial network (GAN) are proposed to predict properties and design alloys. A dataset of 4000 alloys, including the chemical composition of 45 elements, 21 different properties and 75 tempers, is created. ANN models are developed and optimized to predict key properties, demonstrating strong forecasting capabilities. Incorporating temper data into the input features significantly enhances the models’ accuracy, particularly for critical mechanical property prediction. Secondly, GAN is employed to create novel alloy compositions based on the properties and result show its limitation by proposing a unique chemical composition related to the desired properties. An optimized generative collaborative networks (OGCN) is proposed based on two successive models, a generator and a predictor model. Results show its capability to generate alternative chemical compositions that achieve desired properties, demonstrating reliability and industrial value through coherence with known functional compositions.

Magnesium aluminate (MgAl₂O₄) spinel (MAS) is a very promising synthetic material of cubic crystal structure with its excellent mechanical, thermal, chemical, dielectric and optical properties. Due to its superior high-temperature properties and eco-friendliness, it has gained importance as a refractory material for use in steel-teeming ladles, cement rotary kilns and glass tank furnaces. Apart from refractory, polycrystalline MAS is extensively used in optically transparent windows, armours and domes, owing to its high transparency with acceptable pyro-chemical properties. MAS formation from alumina and magnesia involves a volume expansion of 5–8%, which prohibits the formation of dense MAS bodies through a single-stage sintering process. As a result, a more expensive double-stage firing process is required to produce dense MAS ceramics. However, various additives play a significant role in the formation and sintering of MAS through the reaction sintering process. Research has shown that halide doping can lower the spinel formation temperature, enhance densification during sintering and modify the microstructure of MAS, resulting in a notable improvement in its thermo-mechanical properties. This review aims to explore the spinel formation and sintering characteristics of halide-doped MAS.

This research aims to analyse the physical properties of lead-free double perovskites ({text{A}}_{2} {text{GaScI}}_{6}) (where A = Li, Rb, Cs) using first-principles method. The structural stability of the considered material is confirmed through geometry optimization process which includes formation energy, octahedral tilting factor, tolerance factor and analysis of elastic parameters. The electronic properties are evaluated using both generalized gradient approximation (GGA) with Perdew–Burke–Ernzerhof (PBE) and Tran and Blaha modified Becke-Johnson (TB-mBJ) methods through analysis of the density of states and band structures to obtain accurate energy band gaps. Subsequently, the optical parameters, including the absorption coefficient, loss function, optical conductivity, reflectivity, dielectric function, and refractive index, are calculated and analyzed. The results show that all double perovskites exhibit a high absorption coefficient in the visible and UV regions. The calculated mechanical parameters indicated that studied materials are elastically stable, compressible, anisotropic and show high melting temperature. Thermoelectric parameters indicate that electrical and thermal conductivities, power factor, and seebeck coefficient all increase with temperature. The calculated ZT at 300 K is very close to unity and positive seebeck coefficient, indicating p-type behaviour. The calculated band gaps along with optical, thermoelectric and mechanical parameters envisaged that these materials are very suitable for optoelectronic and thermoelectric devices for green energy harvesting.