Ternary intermetallic compounds based on rare-earth metals are characterized by high values of the magnetocaloric effect (MCE) and magnetoresistance, making them suitable materials for a variety of innovative, environmentally friendly and efficient applications. Magnetic refrigeration, for example, is a potential candidate for environmentally friendly gas liquefaction and for preventing gas from evaporating during storage. As an example, liquid nitrogen is often used as a final refrigerant for liquefied natural gas at 111 K. Novel intermetallics GdMn_1−xRu_xSi with a tetragonal CeFeSi-type structure (P4/nmm), were synthesized, with x = 0, 0.2, 0.5, 0.8 and 1 [1]. Their Curie temperature T_C changes from 78.3 to 320 K with a change in manganese content. The electronic structure and magnetic moments of GdMn_1-xRu_xSi intermetallic compounds were calculated using the theoretical DFT+U method. The calculated total magnetic moments of GdMn_1-xRu_xSi also show reduced values for intermediate Ru concentrations. In the GdMn_1-xRu_xSi system, MCE occurs during a second-order phase transition and in a wide temperature range from 78.3 (which is near the boiling point of liquid nitrogen at 77.4 K) to 320 K. The GdMn_1-xRu_xSi system, with x = 0 - 1, is of practical interest for the liquefaction of gases, including nitrogen. A cassette can be made from compounds within this range with slightly varying chemical compositions. Due to their properties, the intermetallic GdMn_1-xRu_xSi compounds are novel, more efficient magnetocaloric materials suitable for the liquefaction of nitrogen and other gases.

1. Platonov, S.P.; Kuchin, A.G.; Volegov, A.S.; Gaviko, V.S.; Mukhachev, R.D.; Lukoyanov, A.V.; Yakovleva, M.Yu. The GdMn_1-xRu_xSi Compounds Cassette for Magnetocaloric Nitrogen Liquefaction. Physica B: Condensed Matter 2024, 685, 416060. https://doi.org/10.1016/j.physb.2024.416060

Electronic structures of all inorganic rare-earth element, such as gadolinium (Gd) and neodymium (Nd), double perovskite crystals (Cs₃GdCl₆ and Cs₃NdCl₆) were characterized for application of photovoltaic devices with photovoltaic performance. The band structure, density of state, electron density distribution, and the real and imaginary parts of the dielectric function of Cs₃GdCl₆ and Cs₃NdCl₆ double perovskite crystals were approximated using first-principles calculations, with GGA-PBE approximation. The Cs₃GdCl₆ and Cs₃NdCl₆ double perovskite crystals had a narrow band dispersion with direct band gaps of 1.0 eV and 0.7 eV. The band structure of the Cs₃GdCl₆ crystal consisted of 5d and 4f orbitals of Gd ions near the valence band (VB) state,the 5d orbital of Gd ions ,and the 6s orbital of Cs ions near the conduction band (CB) state. The band structure of the Cs₃NdCl₆ crystal consisted of the 5p orbital of Cl ions near the VB state, and the 5d orbital of Nd ions near the CB state. The charge transfer and carrier generation related to electron mobility will be caused by the overlap of the 5d orbital of Gd and Nd ions and the 6s orbital of Cs ions near the CB state. The real and imaginary parts of the dielectric function in both cases were obtained in the range of 0 – 1 eV. The photon energies correspond to transition between the energy levels of the split 5d and 4f orbitals of Gd andNd ions coordinated with Cl ions as ligands in the crystal field with charge distribution. The Cs₃GdCl₆ and Cs₃NdCl₆ double perovskite crystals have high potential for the application of photovoltaic devices with photovoltaic performance.

At present, LCDs have completely replaced conventional cathode ray tube (CRT) displays. LCDs offer the advantage of being significantly thinner and lighter, making them highly portable. With advancements in fabrication technology, LCDs have become cost-effective alternatives to CRTs. Over recent decades, extensive research by various groups has focused on liquid crystal (LC)-based nanoparticle (NP) composite materials, a prominent area in LCD-related studies. Research on LC-NP composites allows the exploration of synergistic combinations of LCs and NPs, each contributing unique characteristics. By doping NPs with LCs, properties such as localized surface plasmon resonance (SPR) of metal nanoparticles (MNPs) like Ag, Au, and Pt can be tailored. LCs play a crucial role in modifying NP assembly, thereby influencing the morphological organization of NPs and their remarkable electro-optical and electronic properties, essential for nanoscale device fabrication. Conversely, NPs can also tune the characteristics of LCs, including their EO properties and alignment in display technologies.

This study explores how adding gold nanorods (GNRs) to ferroelectric liquid crystal (FLC) devices affects their properties. GNR concentrations from 0.025 wt.% to 0.1 wt.% were tested. Adding GNRs at 0.025 wt.% and 0.050 wt.% improved optical contrast, tilt angle, absorbance, and photoluminescence intensity. The alignment of FLC composites with GNRs was better, with fewer light leakage centers. Also, the relative permittivity, dielectric loss, and DC conductivity improved with GNR inclusion. This suggests that GNRs can enhance the performance and efficiency of FLC devices.

Organic-inorganic hybrid materials have emerged as a potential candidate due to their fascinating properties for several optoelectronic applications. In this study, lead-free organic-inorganic hybrid perovskite single crystals [N(CH₃)₄]MnCl₃ were synthesized through a slow evaporation method using tetramethylammonium as the organic ligand. Systematic characterizations were carried out to reveal the crystal structure and other optoelectrical properties. A series of systematic characterizations were carried out in order to reveal the crystal structure as well as other optoelectrical features. Phase purity and morphology were confirmed by powder x-ray diffraction and scanning electron microscopy respectively. The crystal has a P 63/m space group which belongs to the hexagonal crystal system. The optical band gap was found to be 2.15 eV, and under the excitation of a suitable UV light source, it can emit 635 nm bright red lights with a full width at half maximum of 78 nm at room temperature. Thermal study indicates that the compound is stable up to 300 °C. The compound's electrical properties were studied using Impedance spectroscopy as a function of frequency from 20 Hz to 4 MHz at different temperatures. Finally, the successful achievement of luminescent printing was made possible by harnessing the exceptional photophysical properties of the material. The printed images demonstrated remarkable clarity even after undergoing multiple cycles and remained visible for a prolonged period of 15 days in an air environment, affirming the stability of the printed images. The information stored on the paper can be easily read using a UV lamp. Therefore, these findings highlight the material's outstanding photoluminescence and optoelectrical properties, suggesting its potential for promising applications in optoelectronics, including light-emitting diodes.

Our main goal was to form various compounds of the chloroacetylation product of p-methoxyphenol (4-methoxyphenyl 2-chloroacetate) with various amines using the Menshutkin reaction. This article presents a part of our research, namely, the reaction process with 2,4-dinitrophenyl hydrazine and its analysis. The process was carried out in different solvents. The expected product of the reaction was 2-(2,4-dinitrophenyl)-1-(2-(4-methoxyphenoxy)-2-oxoethyl)hydrazin-1-ium chloride. Due to regrouping, another product was formed. As a result of our research, 2,4-dinitrophenylhydrazide of monochloroacetic acid (2-chloro-N'-(2,4-dinitrophenyl)acetohydrazide) was formed. Crystal structure analysis was performed. This is of interest because of its potential applications in various fields, including pharmaceuticals and materials science. The synthesis of the compound was achieved by a direct synthetic route and confirmed by spectroscopic methods such as IR, NMR, and elemental analysis. Single-crystal X-ray diffraction analysis provided detailed structural information, revealing the molecular arrangement within the crystal lattice. Crystallographic data revealed a monoclinic crystal system with the space group P21/n, which revealed the molecular conformation, intermolecular interactions, and crystal packing motifs. This comprehensive structural characterization enhances our understanding of the compound's properties and provides valuable insights for further exploration of its potential applications. As a result, a compound with a confirmed crystal structure was entered into the reference of Structures The Cambridge Crystallographic Data Centre (CCDC).

Among nitrogen-containing heterocyclic compounds, triazoles have high pharmacological properties and are therefore of interest for structural and physico-chemical studies. Structurally, triazoles can be divided into two different subsets: 1,2,3-triazole and 1,2,4-triazole. Due to their structural characteristics, 1,2,3- and 1,2,4-triazoles can accommodate a wide range of substituents (electrophiles and nucleophiles) around their core structures, opening the way for the synthesis of various new bioactive substances [1]. Although it has been more than 120 years since the initial discovery of the method for the synthesis of 1,2,3-triazoles by cross-alkynes and azides, the interest in this chemical class of molecules has been increasing rapidly in the last 20 years. The reason for this is the introduction of catalytic methods for cyclization reactions, which made the generation of 1,2,3-triazole derivatives widely accessible for pharmacological applications. With the advancement of click chemistry, scientific work on these five-member heterocyclic compounds is growing rapidly [2]. Here, we report the synthesis and structural characterization of 2-((1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)methoxy)benzaldehyde (1) and 3-((1-(4-nitrophenyl)-1H-1,2,3-triazol-4-yl)methoxy)benzaldehyde (2) using X-ray crystallography. The structures of compounds 1 and 2 were established by single-crystal X-ray diffraction, and the identified conformations were described in the context of their stabilizing intra- and inter-molecular interactions, particularly highlighting the significant hydrogen bonds of the crystals. For molecular crystals, Hirshfeld surface analyses can provide crucial insight into the intermolecular interactions. These analyses were performed to determine intermolecular interactions in 1 and 2. According to our results, the molecules are associated by intra- and intermolecular hydrogen bonds, C—H···π, and N—O···π stacking interactions. The three-dimensional Hirshfeld surface analysis and two-dimensional fingerprint plots revealed that the structures are dominated by H···H, H···C/C···H and H···O/O···H contacts.

Molybdenum disulfide (MoS₂) with single- and odd-numbered layers is a novel piezocatalyst, and its piezocatalytic molecular oxygen activation, which produces reactive oxygen species (ROS), has been considered a promising and low-cost strategy for environmental remediation. However, its performance is still far from satisfactory, and the limited knowledge regarding its molecular oxygen activation process significantly impedes its further development. Herein, several numbered layers of Co-doped MoS₂ ultrathin nanosheets (UNs) with a thickness of 3.2 nm were successfully fabricated via hydrothermal synthesis. The single Co atom-doped odd-numbered layers of MoS₂ nanosheets strongly interacted with adsorbed oxygen molecules for a highly efficient generation of ROS in the piezocatalytic degradation process. The dopant-induced enhanced carrier density (electron density) of Co-doped MoS₂ was 7.7 × 10¹⁸ cm^–3, compared with 2.9 × 10¹⁶ cm^–3 for bare MoS₂. Moreover, the interfacial action of Co-doped MoS₂ nanosheets on directional molecular oxygen activation properties were predicted by DFT calculation and monitored by generated reactive oxygen species (ROS) evolution. Co-doped MoS₂ decomposed tetracycline (an antibiotic) by 99.8% in 15 min through shaking vibration in the dark. It was found that Co active sites can facilitate the one-electron reduction of molecular oxygen activation by introducing a Co²⁺/Co³⁺ redox couple. In addition, a tentative mechanism was proposed to explain the origin of the piezocatalytic enhancement in Co-doped MoS₂. Thus, in order to meet the requirements in the field of wastewater pollutant remediation, the current research effort may provide guidelines for constructing 2D TMDCs piezoelectric catalysts and comprehending the mechanisms of the directional piezoelectric catalytic generation of reactive oxygen species through the doping route.

Introduction:

Broadband emissions related to self-trapped excitons in the sub-bandgap region in organic lead halide perovskite (OLHP) have drawn attention in recent times due to their potential in optoelectronic applications. In this study, we have provided a systematic multi-technique approach to the formation of broad-band emission in OLHPs. We have observed that broad-band emission is closely related to the lattice fluctuation in OLHPs.

Methods:

Single crystals of methylammonium lead chloride (MAPbCl₃), methylammonium lead bromide (MAPbBr₃), and formamidinium lead bromide (FAPbBr₃) were grown using solvent evaporation at room temperature method. Temperature-dependent photoluminescence measurements were performed in Edinburg FLS920 spectrometer, synchrotron X-ray powder diffraction measurements were carried out at the P-02.1 beamline at PETRA III, DESY, and temperature-dependent Raman measurements were carried out in a micro-Raman spectrometer (in Via, Renishaw, UK).

Results:

Temperature-dependent photoluminescence study shows broad-band emission in MAPbCl₃ and MAPbBr₃ in the sub-bandgap region, which is missing in FAPbBr₃. Synchrotron X-ray powder diffraction analysis suggests cubic phase till 172, 235, and 265 K for MAPbCl₃, MAPbBr₃, and FAPbBr₃, respectively. The tetragonal phase transforms to an orthogonal phase at 167, 148, and 150 K, respectively. Interestingly, below 165 K in MAPbCl₃, conventional single Pnma symmetry cannot be fitted with low values of reliability parameters, suggesting the presence of another phase. Temperature-dependent Raman study shows stronger N-H---X hydrogen bonding between MA⁺ cation and PbX₆ octahedra in the orthorhombic phase of MAPbCl₃ and MAPbBr₃ than FAPbBr₃. The study suggests more tilting of the octahedral framework in both the MA-based compounds.

Conclusions:

In summary, our study suggests the emergence of broad-band emission in the two MA-based compounds is due to the transient lattice distortion due to the stronger N-H---X bonding. However, at the lower temperature of MAPbCl₃, the presence of double unit cells stabilizes the transient lattice deformation.

M7C3 carbides (where M could be Fe, Cr, i.e. (Fe, Cr)7C3) or other solution elements replacing Cr or Fe are a special group of carbides, widely used in materials such as white cast iron and welded hardfacings. Normally, the structure of hypereutectic Fe–Cr–C alloy consists of a high quantity of large primary M7C3 carbides within an eutectic matrix. The morphologies of primary M7C3 carbides directly influence the hardness, wear resistance, fracture toughness of the alloy as well as the physical properties such as thermal conductivity and electrical resistance. It is essential to develop a systematic data-led modelling framework to assess the effect of the morphologies on the key properties and functionalities of M7C3 carbides under different loading conditions.

In this paper microstructure based modelling is applied to M7C3 carbides. An effective framework has been developed to transfer microstructure of M7C3 carbides into image databases for statistical structure analysis and modelling. A mechanical-thermal-electrical modelling approach has been developed and is applied to different carbide structures for predicting the effective properties including stiffness, thermal and electrical properties. A new approach is developed to model the structure of individual carbides including the stress concentration factors associated with the shapes and the internal features, which is critical to wear and fracture of the carbides. The key functional feature of the program is presented including microstructure data, image processing and structure models with different scales. The work show that the internal feature could cause significant variation of stress concentration factors under different loading and boundary conditions. The key issues in data development and analysis of the structures are outlined. The link between engineering simulation and first principle calculation of the properties is analysed. The use of modelling for data-driven materials development, quality and performance prediction is discussed.

Due to their diverse properties, zinc oxide nanoparticles (ZnONPs) have shown great potential in various applications. These nanoparticles exhibit unique characteristics, including antimicrobial, anti-inflammatory, wound healing, catalytic, magnetic, optical, and electronic properties, making them useful in various fields. The size and crystalline structure of the material are crucial factors affecting these properties. In recent years, using plant extracts to synthesize nanoparticles has emerged as a technique that allows for the control of the size, shape, and properties of these materials. The main objective of this work is to study the influence of extract concentration and temperature on the synthesis of ZnONPs using Flourensia cernua extract. Zinc nitrate hexahydrate was used as a precursor, and we tried different extract–solvent ratios, such as 0.5:10 and 1:10 w/v. The ZnNPs were synthesized at varying temperatures ranging from 300 to 500 °C. ZnONPs were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectrometry (FTIR). The XRD patterns showed a wurtzite hexagonal phase of ZnO. According to TEM characterization, crystalline particles with a semi-spherical morphology were obtained in a size range between 10 and 22 nm. Interestingly, increasing the amount of extract led to a decrease in the particle size. On the other hand, an increase in the calcination temperature caused the growth of the nanoparticles. This method showed that extract concentration and temperature greatly influence the size of the ZnONPs. The application of these particles in the photodegradation of organic dyes is being studied. Using plant extracts as a green synthesis method for ZnONPs can provide a sustainable and eco-friendly approach to developing customized nanoparticles for various applications.