Search Results (230)

Laser annealing of oxide functional thin films makes them compatible with substrates of various types, especially flexible materials. The effects of optical annealing on Ni-doped ZnO thin films were the subject of investigation and analysis in this study. Using pulsed laser deposition, we deposited polycrystalline ZnNiO films on sapphire and silicon substrates. The deposited film was annealed by laser heating. A continuous CO₂ laser was used for this purpose. The uniformly distributed long-wavelength radiation of the CO₂ laser can penetrate deeper from the surface of the thin film compared to short-wavelength lasers such as UV and IR lasers. After growth, optical post-annealing processes were applied to improve the conductive properties of the films. The crystallinity and surface morphology of the grown films and annealed films were analyzed using SEM, and their electrical parameters were evaluated using van der Pauw effect measurements. We used electrical conductivity measurements and investigated the photovoltaic properties of the ZnNiO film. After CO₂ laser annealing, changes in both the crystalline structure and surface appearance of ZnO were evident. Subsequent to laser annealing, the crystallinity of ZnO showed both change and degradation. High-power CO₂ laser annealing changed the structure to a mixed grain size. Surface nanostructuring occurred. This was confirmed by SEM morphological studies. After irradiation, the electrical conductivity of the films increased from 0.06 Sm/cm to 0.31 Sm/cm. The lifetime of non-equilibrium charge carriers decreased from 2.0·10⁻⁹ s to 1.2·10⁻⁹ s. Full article

Co_0.95R_0.05Fe₂O₄ nanoparticles with R = La, Pr, Nd, Sm, and Eu were synthesized via an environmentally friendly sol–gel method. The prepared samples were studied using X-ray diffraction measurements (XRD), transmission electron microscopy (TEM), X-ray photoelectron microscopy (XPS), and magnetic measurements. All compounds were found to be single phases adopting a cubic Fd-3m structure. EDS analysis confirmed the presence of Co, Fe, R, and oxygen in all cases. The XPS measurements reveal that the Co 2p core-level spectra are characteristic for Co³⁺ ions, as indicated by the 2p_3/2 and 2p_1/2 binding energies and spin–orbit splitting values. The analysis of the Fe 2p core-level spectra reveals the presence of both Fe³⁺ and Fe²⁺ ions in the investigated samples. The doped samples exhibit lower saturation magnetizations than the pristine sample. Very good agreement with the saturation magnetization values was obtained if we assumed that the light rare-earth ions occupy octahedral sites and their magnetic moments align parallel to those of the 3d transition metal ions. The ZFC-FC curves indicate that some nanoparticles remain superparamagnetic, while others exhibit ferrimagnetic ordering at room temperature, suggesting the presence of interparticle interactions. The M_r/M_s ratio at room temperature reflects the dominance of magnetostatic interactions. Full article

Silica fume-based geopolymer composite coatings, an approach to using metallurgical solid waste, exert flame retardancy with ecological, halogen-free, and environmentally friendly advantages, but their fire resistance needs to be improved further. Herein, a silica fume-based geopolymer composite flame-retardant coating was designed by doping boric acid (BA), zinc phytate (ZnPA), and melamine (MEL). The results of a cone calorimeter demonstrated that appropriate ZnPA and BA significantly enhanced its flame retardancy, evidenced by the peak heat release rate (p-HRR) decreasing from 268.78 to 118.72 kW·m⁻², the fire performance index (FPI) increasing from 0.59 to 2.83 s·m²·kW⁻¹, and the flame retardancy index increasing from 1.00 to 8.48, respectively. Meanwhile, the in situ-formed boron phosphate (BPO₄) facilitated the residual resilience of the fire-barrier layer. Furthermore, the pyrolysis kinetics indicated that the three-level chemical reactions governed the pyrolysis of the coatings. BPO₄ made the pyrolysis E_α climb from 94.28 (P5) to 127.08 (B3) kJ·mol⁻¹ with temperatures of 731–940 °C, corresponding to improved thermal stability. Consequently, this study explored the synergistic flame-retardant mechanism of silica fume-based geopolymer coatings doped with ZnPA, BA, and MEL, providing an efficient strategy for the high-value-added recycling utilization of silica fume. Full article

Dielectric capacitors have become a key component for energy storage systems, owing to their exceptional power density and swift charge–discharge performance. In a series of lead-free ferroelectric ceramic materials, BaSn_xTi_1-xO₃ (BTS) received widespread attention due to its unique properties. However, BTS ceramics with high Sn content have high efficiency (η) but low recovery energy storage density (W_rec). We incorporated the Sm element into BTS ceramics and aimed to optimize both efficiency and recoverable energy density at moderate Sn content. With the synergistic effect between Sm and Sn, the optimal composition was found at 5% Sn content with 1% low-level Sm dopants, where the energy storage density reached 0.2310 J/cm³ at 40 kV/cm. Furthermore, the thermal stability of the ceramic was investigated using temperature-dependent dielectric spectroscopy, in situ XRD, and temperature-dependent hysteresis loops. With Sm doping, the fluctuation of W_rec decreased from 18.48% to 12.01%. In general, this work not only enhances the understanding of samarium dopants but also proposes strategies for developing lead-free ferroelectric ceramics with superior energy storage properties. Full article

Chalcopyrite (CuFeS₂) has attracted interest as a thermoelectric material due to its narrow bandgap and its ability to tailor its carrier concentration through doping. In this study, we investigated the effects of Ni²⁺ substitution at Cu⁺ sites in chalcopyrite (Cu_1−xNi_xFeS₂) on its structural, microstructural, and thermoelectric properties. Samples were synthesized using mechanical alloying followed by hot pressing to ensure high-density compaction. X-ray diffraction analysis confirmed the formation of the tetragonal chalcopyrite phase without detectable secondary phases. The observed reduction in lattice parameters with increasing Ni content provided evidence of successful Ni incorporation at Cu sites within the chalcopyrite structure. Microstructural analysis and elemental mapping further supported the uniform distribution of Ni within the chalcopyrite matrix. Thermoelectric property measurements revealed that Ni-doped chalcopyrite exhibited n-type conduction. As the Ni concentration increased, the carrier concentration and electrical conductivity increased significantly, with Cu_0.92Ni_0.08FeS₂ achieving the highest electrical conductivity of 2.5 × 10⁴ Sm⁻¹ at 723 K. However, the absolute value of the Seebeck coefficient decreased with increasing Ni doping, following the expected trade-off between electrical conductivity and thermopower. The optimized composition, Cu_0.96Ni_0.04FeS₂, exhibited the highest thermoelectric performance, with a power factor of 0.50 mWm⁻¹K⁻² and a maximum dimensionless figure of merit (ZT) of 0.18 at 623 K. Compared to undoped chalcopyrite, these enhancements represent a 43% increase in power factor and a 50% improvement in ZT. Full article

Synthesis and characterization of undoped and samarium-doped CuO–SnO₂:F thin films using the spray pyrolysis technique are presented. The effect of the samarium doping level on the physical properties of these films was thoroughly analyzed. X-ray diffraction patterns proved the successful synthesis of pure CuO–SnO₂:F thin films, free from detectable impurities. The smallest crystallite size was observed in 6% Sm-doped CuO–SnO₂:F thin films. The 6% Sm-doped CuO–SnO₂films demonstrated an increasedsurface area of 40.6 m²/g, highlighting improved textural properties, which was further validated by XPS analysis.The bandgap energy was found to increase from 1.90 eV for undoped CuO–SnO₂:F to 2.52 eV for 4% Sm-doped CuO–SnO₂:F, before decreasing to 2.03 eV for 6% Sm-doped CuO–SnO2:F thin films. Photoluminescence spectra revealed various emission peaks, suggesting a quenching effect. A numerical simulation of a new solar cell based on FTO/ZnO/Sm–CuO–SnO₂:F/X/Mo was carried out using Silvaco Atlas software, where X represented the absorber layer CIGS, CdTe, and CZTS. The results showed that the solar cell with CIGS as the absorber layer achieved the highest efficiency of 15.98. Additionally, the thin films demonstrated strong photocatalytic performance, with 6% Sm-doped CuO–SnO₂:F showing 86% degradation of ampicillin after two hours. This comprehensive investigation provided valuable insights into the synthesis, properties, and potential applications of Sm-doped CuO–SnO₂ thin films, particularly for solar energy and pharmaceutical applications. Full article

This study presents the fabrication of a samarium-doped Ti/Sb-SnO₂/PbO₂ electrode and investigates its applications in polluted water treatment and energy conversion. Physicochemical properties were characterized by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray powder diffraction analysis, and Raman spectroscopy. The Ti/Sb-SnO₂/Sm-PbO₂ electrode showed 2.5 times higher oxygen evolution potential activity than the Ti/Sb-SnO₂/PbO₂ electrode. Density Functional Theory was used to conduct first-principles calculations, and the obtained results indicated that Sm doping enhances the production of reactive oxygen species. The application of the Ti/Sb-SnO₂/Sm-PbO₂ electrode in carbendazim (CBZ) removal was investigated, since CBZ is a fungicide whose presence in the environment, including food, water, and soil, poses a threat. After 60 min of the treatment under optimized working parameters, the degradation rate of CBZ reached 94.2% in the presence of 7.2 g/L Na₂SO₄ with an applied current density of 10 mA/cm² in an acidic medium (pH 4). Of the four investigated parameters, the current density had the most significant influence on the degradation process. At the same time, the initial pH value of the solution was shown to have the least impact on degradation efficiency. These results imply a potential use of the proposed treatment for CBZ removal from wastewater. Full article

Solar energy-absorbing and -storing integrated ceramics are a new type of material that absorbs sunlight and stores it as heat energy, with properties such as high absorptivity, high thermal storage density, and high temperature stability. In this study, forsterite ceramics were prepared from fused magnesia, quartz, α-Al₂O₃, and Sm₂O₃, and concurrently, two additives of Fe₂O₃ and CuO were doped to improve the absorptivity, and the effects of the composite additives on the performance of forsterite ceramics were investigated. The results showed that the optimal Fe₂O₃/CuO content ratio was 8:2, at which time the apparent porosity, bulk density, and thermal storage density of the sample were 0.21%, 3.08 g/cm³, and 1516.71 kJ/kg (1000 °C), respectively. After 30 thermal shock cycles, the precipitation of samarium silicate in the samples resulted in a tighter grain bonding, increased the bending strength by 70.6%, and exhibited excellent thermal shock resistance. The solar absorptivity reached 93.80% in the 0.3–2.5 μm wavelength range. Fe₂O₃ doping replaced part of the positions of Al³⁺ in MgAl₂O₄ to form MgFe_0.6Al_1.4O₄ phase. This replacement caused lattice distortion, which triggered electronic transition and augmented the intrinsic absorption capacity, thereby enhancing the sample’s absorptivity. CuO’s low reflectivity across the spectrum further reduced sample reflectivity. Full article

In this paper, using the Materials Studio software (version 2020) and based on first-principles and density functional theory, the effects of Sm³⁺ doping at different ratios (1/12, 1/6, and 1/3) on the crystal structure and Mulliken charge distribution of bismuth silicate (Bi₄Si₃O₁₂, BSO) were analyzed. The examination of the crystal framework and Mulliken charge allocation reveals that increasing levels of Sm³⁺ doping have the potential to warp the lattice’s symmetry and result in a decrease in electrical conductivity. With the rise in the concentration of Sm³⁺ doping, the Sm-O bond length shows a pattern of a rise at first and then a fall, demonstrating that electrons are shared, and reaches its minimum length with a doping proportion of 1/12. At the same time, when the doping concentration of Sm³⁺ rises, the Bi-O bond length becomes longer; it reaches its shortest length when the doping concentration is 1/12. This finding suggests that when a small quantity of Sm³⁺ is doped, especially when the doping concentration is 1/12, the covalent nature of the bonds between Sm-O and Bi-O atoms within the BSO crystal is strengthened. Full article

In this work, a novel potential thermal barrier coating material entropy-stabilized titanium–aluminum oxide (La_0.25Ce_0.25Nd_0.25Sm_0.25)Ti₂Al₉O₁₉ (META) was successfully synthesized by the solid-state reaction method, and its thermophysical properties, phase stability, infrared emissivity, mechanical properties, and CMAS corrosion resistance were systematically investigated. The results demonstrated that META exhibits low thermal conductivity at 1100 °C (1.84 W·(m·K)⁻¹), with a thermal expansion coefficient (10.50 × 10⁻⁶ K⁻¹, 1000–1100 °C) comparable to yttria-stabilized zirconia (YSZ). Furthermore, META displayed desirable thermal stability, high emissivity within the wavelength range of 2.5–10 μm, and improved mechanical properties. Finally, META offers superior corrosion resistance due to its excellent infiltration inhibiting. The bi-layer structure on the corrosion surface prevents the penetration of the molten CMAS. Additionally, doping small-radius rare-earth elements thermodynamically stabilizes the reaction layer. The results of this study indicate that (La_0.25Ce_0.25Nd_0.25Sm_0.25)Ti₂Al₉O₁₉ has the potential to be a promising candidate for thermal barrier coating materials. Full article

In this work, a multicomponent PZT-type material doped with manganese Mn, antimony Sb, samarium Sm, and tungsten W was fabricated using classical powder technology. Sintering of the ceramic samples was performed by the free sintering method (pressureless sintering). The influence of samarium on the properties of PZT was analyzed using a variable amount of samarium Sm³⁺ (from 0.8 to 1.2 wt.%) and tungsten W⁶⁺ (from 1.4 to 1.2 wt.%) admixture compared to the Pb(Zr_0.49Ti_0.51)_0.963Mn_0.021Sb_0.016O₃ + W⁶⁺1.8 wt.% reference composition. XRD studies have shown that PZT-type ceramic samples have a tetragonal structure with a point group of P4mm. Field emission scanning electron micrographs (FE-SEMs) showed fine and properly crystallized grains with an average grain size of 5.65–7.70 μm and clearly visible grain boundaries. The polarization–electric field (P-E) hysteresis measurement confirmed the ferroelectric nature of the ceramic materials with high P_m maximum polarization values (from 12.38 to 16.46 μC/cm²). Dielectric studies of PZT-type materials have revealed high permittivity values (from 1025 to 1365 at room temperature (RT) and from 18,468 to 25,390 at phase transition temperature T_m) with simultaneously low tanδ dielectric loss factor values (from 0.004 to 0.011 at RT) and low DC electrical conductivity, which are important parameters for microelectronic applications. The most homogeneous structure and the most favorable set of utility parameters are represented by the composition with an equal content of Sm and W admixtures, i.e., for 1.2 wt.%. Full article

Rare earth element (Sm)-doped potassium sodium niobate (KNN)-based ceramics are fabricated using spark plasma sintering method and their properties are investigated. The results show that all the samples crystallize in a typical perovskite structure with a single orthorhombic phase. With increasing the Sm doping, the ceramics gradually shift toward the relaxor ferroelectric state and the value of dielectric loss angle tangent (tanδ) is smaller than 0.05 for x ≤ 0.003 ceramic samples. Meanwhile, the optimized piezoelectric charge coefficient d₃₃ = 128 pC/N, and piezoelectric voltage coefficient g₃₃ = 18.9 × 10⁻³ Vm/N are obtained when x = 0.001. Compared with the undoped sample, the d₃₃ of x = 0.001 ceramics has been significantly enhanced by 28%. The positron annihilation lifetime results indicate that the main defect types in the ceramics are the A-site vacancies and defect dipoles. Based on the aforementioned results, the optimized piezoelectric performance and the lowest defect dipoles concentration in x = 0.001, may be attributed to the low internal oxygen vacancy concentration in it. This work may provide insights for the further study of KNN-based piezoelectric ceramics. Full article

The tetragonal R_1−xZr_x(FeCo)₁₁Ti alloys, where R is a rare earth and Ti a transition metal, are promising candidates for permanent magnets. Sm_1−xZr_x(Fe_0.8Co_0.2)_12−yTi_y (x = 0 and 0.25; y = 1 and 0.7) master alloys were prepared by arc melting under argon atmosphere. Some of the samples were almost single-phase compounds at 1:12, with a very small amount of a-Fe(Co). Partially replacing Sm with Zr produced alloys with small amounts of Sm(FeCo)₂ Laves-type phases. The as-cast ingots were milled using high-energy ball milling (HEBM) for different times in an argon atmosphere and then annealed at 973 K–1173 K at different interval times (15–90 min). After annealing, the sample milled for 4 h contained a large variation of grain size from 2–4 μm to 20 μm or larger, while, after annealing, the other sampled milled for 8 h exhibited grains size in the range of 2–6 μm; therefore, their coercivity was higher, reaching a maximum value of 5.5 kOe for SmFe₉Co₂Ti annealed at 1123 K for 60 min. Coercivity was strongly affected by the annealing temperature and time. The microstructure evolution with emphasis on the particles size during annealing and their correlation with coercivity are herein discussed. Full article

This paper describes the synthesis and evaluation of samarium-doped 45S5 bioactive glass in various ratios. The bioactive glass samples were prepared using the sol–gel method and subjected to a heat treatment at 700 °C in normal atmosphere. The obtained samples were analyzed by thermogravimetric analysis (TGA) before and after the heat treatment to assess their thermal stability and compositional changes. The bioactivity of the samples was tested in vitro by immersion in simulated body fluid (SBF) at 36.5 ± 0.5 °C (normal human body temperature) and pH 7.4 (the pH of the human blood plasma), for several time periods. During the test, the pH and conductivity of the SBF solutions were monitored to track ion migration. After the in vitro test, the mass loss was evaluated and the formation of hydroxycarbonate apatite (HCA) was analyzed by FTIR spectroscopy. The microstructure of the bioactive glasses was examined using scanning electron microscopy (SEM) and the density of bioactive glass was also determined using Archimedes’ principle. This study also investigated the antimicrobial and anti-biofilm properties of both undoped and samarium-doped 45S5 bioactive glass through qualitative and quantitative assays against a range of microorganisms, including Gram-negative, Gram-positive, and yeast reference strains. The results were compared with literature data on melt-derived bioactive glass to evaluate the effects of Sm doping and the sol–gel synthesis method on bioactive glass performance. Full article

The auto-thermal reforming (ATR) of acetic acid is an effective hydrogen production method, but it suffers from catalyst deactivation by coking. Sm-promoted layered La₂NiO₄ perovskite catalysts were synthesized via the sol–gel method and its catalytic performance in the ATR of HAc was further evaluated. The characterization results demonstrate that the incorporation of Sm into the lattice of La₂NiO₄ perovskite led to the formation of Ni-La-Sm-O species, inducing crystal defects in the perovskite structure which could promote the gasification of coking precursors. Additionally, Sm regulated the reduction characteristics of La₂NiO₄, resulting in the formation of highly dispersed nickel nanoparticles upon the hydrogen reduction, which increased the number of active sites available for acetic acid conversion. Consequently, a stable reactivity without obvious coking was obtained over a Ni_0.42La_0.7Sm_0.36O_2.01±δ catalyst within the ATR of Hac. The hydrogen yield reached 2.53 mol-H₂/mol-HAc along with the complete conversion of acetic acid. Full article