This work investigates the quaternary Heusler alloy CoFeZrSi using a first-principles approach to assess its potential for spintronic and optoelectronic applications. Heusler compounds are of significant interest due to their versatile electronic and magnetic properties, particularly their ability to exhibit half-metallic ferromagnetism, which is essential for efficient spintronic devices. This study aims to provide a comprehensive understanding of CoFeZrSi by examining its structural, electronic, magnetic, mechanical, and optical behaviors.

Calculations were performed within the framework of density functional theory (DFT) using the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k code. Three atomic arrangements based on the F-43m space group (Y1, Y2, and Y3) were analyzed. Structural optimization revealed that the Y1-type configuration is the most energetically favorable. Electronic properties were computed using both the generalized gradient approximation (GGA-PBE) and the modified Becke–Johnson (TB-mBJ) potential.

The results show that CoFeZrSi exhibits half-metallic ferromagnetism with an indirect band gap of 0.657 eV (GGA) and 1.451 eV (TB-mBJ) in the minority-spin channel. The total magnetic moment is 1 μB per formula unit, in accordance with the Slater–Pauling rule. Elastic constants confirm mechanical stability and ductility, with favorable values of bulk modulus, shear modulus, Poisson’s ratio, and Pugh’s ratio.

Optical analyses indicate strong interband transitions and high absorption in the visible and ultraviolet ranges, as evidenced by the dielectric function, absorption coefficient, and energy loss spectra.

In conclusion, CoFeZrSi demonstrates robust half-metallicity, mechanical reliability, and strong optical activity, suggesting it is a promising candidate for use in next-generation spintronic and optoelectronic technologies.

References:

1. Ş. Ţălu, Micro and nanoscale characterization of three dimensional surfaces. Basics and
applications. Napoca Star Publishing House, Cluj-Napoca, Romania, 2015.

Abstract
Cadmium sulfide nanoparticles with tunable optical properties were synthesized using two methods: Successive Ionic Layer Adsorption and Reaction and sonochemical synthesis, with Cd:S molar ratios varied from 1:0.1 to 1:1. The SILAR method produced flexible CdS/polyvinyl alcohol composite films, while the sonochemical method yielded highly crystalline CdS powders under ambient conditions. Structural analysis revealed phase transitions from hexagonal to mixed cubic–hexagonal and amorphous structures depending on sulfur concentration, demonstrating the critical role of precursor stoichiometry.

Optical characterization showed a decrease in the band gap with increasing sulfur content, attributed to quantum confinement effects and defect state modulation. Photoluminescence measurements under 330 nm excitation indicated that emission intensity, spectral position, and broadening were significantly influenced by synthesis route and stoichiometry. Sonochemically synthesized nanoparticles exhibited broad, defect-related emissions, while SILAR-based CdS/PVA films displayed more intense, red-shifted, and stable luminescence due to exciton confinement and polymer interaction.

The highest PL efficiency was observed at a 1:0.25 Cd:S ratio, providing an optimal balance between crystallinity and defect density. These findings demonstrate that synthesis method, stoichiometry, and matrix environment critically affect the structural and photoluminescent properties of CdS nanoparticles, offering practical insights for tailoring these materials for optoelectronic and photonic applications.
These results confirm that the synthesis method and stoichiometry critically influence the emission, defect structure, and crystal phase of CdS nanoparticles, enabling tunable properties for optoelectronic and photocatalytic use.

Background: Multidrug-resistant (MDR) organisms pose an increasingly significant public health challenge, complicating the treatment of numerous healthcare-associated infections with standard topical medications and antibiotics. Among the MDR bacteria, Staphylococcus aureus and Shigella sonnei stand out as virulent agents responsible for severe disease. This study aimed to explore a novel biogenic antibacterial agent as a potential alternative to traditional antibiotics for combating Staphylococcus aureus and Shigella sonnei.

Method: The study involved synthesizing zinc oxide nanomaterial (ZnONM) from the mushroom Ganoderma lucidum and examining its antibacterial potency. To characterize the synthesized nanomaterials, several analytical techniques were performed, including UV-vis spectral analysis, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTA), and dynamic light scattering (DLS). Later, a minimum inhibitory concentration (MIC) test and biofilm inhibition assay (at 4*MIC, 2*MIC, MIC, ½*MIC doses) were conducted to evaluate the antibacterial potency of the synthesized green ZnONM.

Results: The results showed that the synthesized ZnONM samples were monodisperse, moderately stable, and had a mean size distribution of 257.2 nm. The MIC value of ZnONM was 625 μg/ml for both MDR pathogens, with biofilm disruption rates at approximately 60% for S. aureus and 5% for S. sonnei. In addition, ½ MIC of ZnONM showed higher biofilm inhibition of S. aureus than higher doses. Remarkably, in the case of S. aureus, the antibacterial effect of ZnONM was almost 1.6 times more effective than that of azithromycin. Furthermore, a strong positive Pearson correlation between ½*MIC and biofilm disruption for S. aureus highlighted the potential effectiveness of lower-dosage treatments in managing biofilm-related S. aureus infections.

Conclusion: Overall, the present study successfully demonstrated the synthesis of ZnONM, which exhibited promising antibacterial activities at lower concentrations. This highlights its antimicrobial potency as an effective alternative to antibiotics against MDR Staphylococcus aureus and Shigella sonnei.

The textile industry has demonstrated a keen interest in developing techniques that enhance the value of end products. A pivotal aspect of this endeavour involves the functionalization of articles, a process that introduces new characteristics without compromising the fundamental properties of fibrous materials. Among the numerous treatments applied to textiles, flame retardancy stands out as a significant concern. Cellulosic fabrics, being highly flammable, find application in various sectors, particularly in the domestic and clothing industries. Given their critical role in sectors where direct contact with humans is inevitable, health and safety concerns are paramount. In this study, we aimed to develop viable alternatives using highly crystalline and resistant materials, known as metal–organic materials (MOFs), to retard flame's action on cotton fabrics. Materials UiO-66 and MOF-808 were developed, compared, and integrated into the fabric using the Layer-by-Layer (LBL) technique, with the objective of enhancing the potential for flame-retardant functionalization of the fabric. The materials produced were characterized using scanning electron microscopy (SEM). The flame-retardant functionality of the fabric was verified using a flammability test method in accordance with European Standard EN ISO 15025:2002—Protective clothing—Test method for limited flame propagation. UIO-66 had a defined shape, as has already been seen in the literature. In consideration of the flame-retardant properties exhibited by cotton fabric in response to treatment with the two MOFs, the fabric subjected to UiO-66 demonstrated effective extinguishment of the flame, while the fabric exposed to MOF-808 exhibited failure to impede the progression of combustion and subsequent complete consumption. Consequently, this study proposed a promising alternative for the development of cellulose fabrics with flame-retardant properties, contributing to consumer safety and advancing the field of textile functionalization. Moreover, it demonstrates that the MOF structure can contribute to the flame-retardant effect of the fabric according to the material produced.

Magneto-plasmonics (MP) refers to multifunctional nanomaterials that exhibit both plasmonic and magnetic properties concurrently. This integration of magnetism and photonics at the nanoscale is typically accomplished by combining plasmonic materials, such as Au and Ag, with magnetic substances, including 3D metals and their oxides. In this study, we present experimental findings on the laser ablation synthesis in solution (LASiS) of Au-Fe (oxide) core–shell nanoparticles (NP) in water. Our approach consists of two steps: first, a gold target is subjected to 1064 nm (400 ns; 0.5 mJ) pulses from a fiber laser at 50 kHz, resulting in pure Au. A colloidal solution with an optical density (OD) of 1 at 520 nm—corresponding to ~0.1 mg/mL of Au—was obtained in this step and was used as the medium for the second step, involving the ablation of an iron target under identical laser conditions. Various LASiS configurations were explored, with different Au0 and Fe-target ablation durations. Consequently, optimal Au and Fe colloidal concentrations were established to synthesize very stable hybrid Au-Fe (oxide) nanoparticle solutions. NP characterization using UV-Vis spectrometry reveals a surface plasmon band centered at 530 nm, which corresponds to the solution's vibrant purple color; additionally, DLS and TEM analyses indicate spherical NPs with an average size of 10 nm. Characterization of the NP structure through EDS and XPS confirms the presence of iron oxide, which explains why a small neodymium magnet placed at the bottom of a test tube filled with the colloidal solution can attract all the NPs to the bottom in under 5 minutes. These core–shell Au-Fe (oxide) NPs represent promising materials for biophotonic applications, including bioseparation, in vivo imaging, and sensing. As a proof-of-concept experiment, we effectively utilized our Au-Fe (oxide) NPs as substrates in Surface-Enhanced Raman Spectroscopy (SERS) tests to detect trace amounts of biological molecules, such as amino acids and urea, in aqueous solutions.

Various strategies are being explored to produce clean and renewable fuels and to efficiently convert their stored energy. Among emerging materials, metal-free three-dimensional (3D) hierarchical porous carbon structures have gained attention as promising candidates for electrocatalytic water splitting. In particular, laser-induced graphene (LIG) electrodes stand out due to their high stability, favorable electronic properties, low resistance, and large surface area. During LIG formation, the heat generated by laser irradiation breaks C–O, C=O, and C–N bonds, releasing gaseous products and promoting the rearrangement of carbon atoms into aromatic structures with sp² hybridization. One of the main challenges in advancing these materials lies in understanding their surface chemistry, especially the role of structural defects that enable their functionalization for various applications. In this work, the LIG electrode was fabricated using different laser powers at 100 mm.s^-1. These electrodes were characterized using synchrotron-based X-ray photoelectron spectroscopy (XPS). The chemical depth profiles were investigated by varying the incident photon energies from 100 to 1200 eV (i.e., kinetic energy). The results revealed a decrease in the intensity of the sp³ (C 1s) component and associated defects with increasing kinetic energy. Additionally, the contribution of the sp² (C 1s) component relative to the total oxygen content increases at higher kinetic energies. XPS quantification reveals not only variations in the surface and sub-surface chemical composition with different laser powers but also corresponding changes in the chemical depth profile. These findings highlight important aspects often overlooked when using such electrodes in practical applications, where surface chemistry plays a critical role.

The development of efficient artificial photocatalysts is a promising strategy for addressing global energy and environmental challenges. Polymeric carbon nitride (CN) has emerged as a strong candidate for photocatalytic hydrogen (H₂) evolution due to its favorable electronic structure and ease of synthesis. However, its performance is limited by the rapid recombination of photogenerated charge carriers. To overcome this limitation, CN was synthesized through the thermal polycondensation of melamine and subsequently modified with nickel (Ni) cocatalysts through magnetron sputtering. The Ni loading was precisely tuned by adjusting the deposition time, reaching up to 0.11 wt%. A range of characterization techniques, including UV-Vis spectroscopy, FTIR, XRD, SEM, XPS, and XAS, was used to evaluate the structural and electronic properties of the CN-Ni materials. The results confirmed the presence of Ni²⁺ species, primarily as NiOx and Ni(OH)x, which contributed to the improved charge separation by acting as hole and electron scavengers. Additionally, the incorporation of Ni led to modifications in the nitrogen bonding states without altering the bulk structure of the CN. These changes correlate with enhanced photocatalytic activity, supporting a proposed mechanism based on the interaction between CN and different Ni species. This study provides meaningful insights into the design of non-noble-metal-based photocatalysts for sustainable hydrogen production.

Climate change-induced abiotic stresses, such as drought, salinity, and extreme temperatures, pose significant threats to global agriculture, reducing crop yields and jeopardizing food security. Nanotechnology has emerged as a promising tool to address these challenges by enhancing crop resilience and productivity under adverse environmental conditions. This study focuses on the synthesis, characterization, and application of advanced nanomaterials designed to mitigate abiotic stress in crops. Using eco-friendly green synthesis methods, we have developed nanomaterials including nanocarriers for stress-responsive molecules, nanoscale nutrient delivery systems, and protective nanocoatings. These materials were characterized using advanced techniques, including TEM, XRD, and FTIR, to ensure their structural and functional properties are optimized for agricultural applications. The nanomaterials were tested under simulated stress conditions, demonstrating significant improvements in seed germination, root development, and overall plant growth. For instance, nano-enabled platforms enhanced water retention, nutrient uptake, and antioxidant activity in plants, enabling them to withstand drought and salinity stress more effectively. Field trials conducted in drought-prone and saline-affected regions further validated these findings, showing increased crop yields and reduced water requirements. This research highlights the potential of nanotechnology to revolutionize agriculture by providing sustainable, scalable, and cost-effective solutions to improve crop resilience. By addressing the challenges posed by climate change, these nanomaterials offer a pathway to enhance food security and support sustainable farming practices. The integration of nanotechnology into agriculture not only improves crop performance under stress but also contributes to the development of climate-resilient agricultural systems for the future.

Given the growing prevalence of heavy crude oil in global petroleum reserves, refinery outputs of heavy oil byproducts (including petroleum asphalt and FCC slurry) have exhibited consistent annual growth. The realization of clean, high-value applications for heavy oil resources has emerged as a pivotal challenge confronting the petroleum refining sector. Characterized by abundant availability, cost-effectiveness, and elevated carbon content, heavy oil represents an exceptional precursor material for carbon-based nanomaterials. Herein, we employed heavy oil derivatives such as petroleum asphalt and FCC slurry as carbon sources to synthesize two-dimensional ultrathin graphene-like materials through an innovative "bottom-up" synthesis strategy incorporating template-assisted and molten salt-mediated methodologies. By introducing metal species in situ during carbonization, we successfully achieved the self-assembly of two-dimensional graphene-analogous frameworks incorporating atomically dispersed metal sites (M-Nx-C, where M = Fe, Co, Pd, etc.), with precise engineering of electronic coupling between the metallic centers and carbon matrices. Through systematic modulation of the metal centers' coordination environments, the developed single-atom M-Nx-C catalysts exhibited remarkable catalytic performance and exceptional chemoselectivity in hydrogenating nitroaromatics containing diverse sensitive functional groups (such as -CHO and -C≡C). This research establishes a fundamental framework for developing next-generation catalysts for selective hydrogenation processes while pioneering an innovative approach to the high-value transformation of heavy oil resources.

Understanding the thermal transport properties of nanoscale gallium nitride (GaN) is essential to ensure reliable operation and prevent overheating in high-power applications. Although previous works have attempted to investigate the thermal properties of GaN films on various substrates, such as sapphire and Si, these substrates could influence the measured results. To address this issue, we aim to investigate the thermal properties of suspended GaN films with thicknesses down to 82nm using the Raman technique.

To achieve the suspended GaN structure, the samples composed of GaN/AlInN on GaN template/sapphire were processed through microfabrication and wet chemical etching of a lattice-matched Al_0.83In_0.17N layer. The Raman measurement was directly performed on the suspended bridge. The heat conduction model is defined as κ = χ_A (L/2Wh)(δω/δP)⁻¹, where κ is the thermal conductivity, L is the length from the center of the bridge to the anchor, W is the width, h is the thickness, χ_A is the temperature coefficient due to anharmonic phonon interaction, and δω/δP is the change in Raman shift at different power levels.

As a result, we obtained κ values of 70±7 and 87±5 Wm⁻¹K⁻¹ for the suspended GaN thin films with thicknesses of 82nm and 160nm, respectively. These values are consistent with theoretical predictions from first-principles lattice dynamics. In addition, it was previously reported that the κ value of non-suspended GaN on a Si substrate decreases from 136 to 127 Wm⁻¹K⁻¹ as the thickness increases from 1300 to 300nm, asmeasured by the time-domain thermoreflectance method. This suggests that the κ values of GaN films for both suspended and non-suspended structures decrease with decreasing thickness due to boundary and surface scattering.

The current study presents an accurate strategy to evaluate the thermal conductivity of the suspended GaN without the effect of the substrate.