Vol. 4 No. 3 (2026): November

Porous MgO and NiO/MgO nanocomposites have attracted significant attention due to their potential applications in heterogeneous catalysis. In this study, MgO and NiO/MgO nanostructures were successfully synthesized using a modified citrate precursor method. The structural and textural properties of the obtained materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and nitrogen adsorption–desorption (BET) analysis. The results reveal that the synthesized MgO exhibits a high specific surface area of up to 230 m²/g with particle sizes ranging from 5 to 20 nm. The incorporation of NiO into the mesoporous MgO matrix leads to changes in pore structure and particle growth behavior. The modified synthesis approach enables improved control over crystallite size and porosity compared to conventional methods. These findings suggest that the prepared materials are promising candidates for catalytic applications.

Water pollution caused by dye pollutants such as methyl orange (MO) can have a negative impact on humans, living organisms, and ecosystems. Adsorption is one of the promising methods in overcoming the presence of MO pollutants. This research focuses on the synthesis of layered double hydroxide (LDH) Ni/Al composites prepared by coprecipitation method with the addition of green tea/Camellia sinensis (CS) leaf extract as supporting material. The synthesized materials obtained were then characterized using X-ray diffraction (XRD) patterns and Fourier transform infrared spectra (FTIR). The Ni/Al and Ni/Al-CS materials were then evaluated as adsorbents to adsorb MO from aquatic solutions. The maximum capacity of MO adsorption obtained was 18.519 mg.g⁻¹ on Ni/Al LDH and 49.261 mg.g⁻¹ on Ni/Al-CS, respectively. The Langmuir isotherm model showed the best fit to the adsorption data on both materials, while the kinetics of the adsorption process followed a pseudo second-order (PSO) model. Thermodynamic analysis (ΔG°, ΔS°, and ΔH°) showed that the MO adsorption process on both materials was spontaneous and endothermic. The regeneration process carried out four consecutive regeneration cycles showed that Ni/Al-CS material has excellent adsorbent recycling ability, which only decreased by 10.26%. In contrast to Ni/Al LDH which experienced a significant decrease of up to 31.70% in the 4^th cycle. These findings suggest that Ni/Al CS material is a promising adsorbent for MO removal applications from aquatic solutions.

This study investigates the influence of internal electric field modulation on photoluminescence (PL) broadening in polar InGaN/GaN quantum wells (QWs). By applying an external bias, the internal electric field is effectively controlled, allowing systematic evaluation of its role in spectral broadening. Photoluminescence and electro-reflectance measurements reveal that reducing the internal electric field leads to a noticeable narrowing of the PL linewidth. A theoretical model is developed to describe the relationship between electric field fluctuations and emission energy variation. The results indicate that stronger internal electric fields enhance the sensitivity of emission energy to local potential fluctuations, thereby increasing PL broadening. Additionally, a reduction in the Huang-Rhys factor is observed under decreased electric field conditions, suggesting weakened exciton-phonon coupling. These findings provide direct experimental evidence of the role of internal electric fields in PL broadening and offer a pathway for spectral control in III-nitride optoelectronic devices.

This study aims to fabricate and optimize silver nanoparticle (AgNPs)-loaded filters for enhanced bacterial removal and water purification. Two types of silver were utilized: commercially available silver (Ag1) and laboratory-synthesized silver (Ag2), prepared via a redox displacement method. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy-dispersive X-ray spectroscopy (EDS), confirming their nanoscale size, crystalline structure, and elemental composition. Various types of filter papers, including membrane and cellulose-based filters, were prepared with and without silver nanoparticle loading. Structural modifications such as layer separation and adhesive incorporation were also investigated to evaluate their impact on filtration performance. The antibacterial activity of the prepared filters was assessed against Escherichia coli ATCC 25922 using the plate count method.
The results demonstrated that AgNPs-loaded filters exhibited significantly enhanced antibacterial efficiency, achieving complete removal (100%) of E. coli in selected configurations, while unloaded filters showed lower removal efficiencies ranging from 53% to 68%. Water quality analysis revealed that total dissolved solids (TDS), electrical conductivity (EC), and pH remained within acceptable drinking water standards after filtration. Furthermore, atomic absorption spectroscopy (AAS) analysis confirmed that the concentration of silver released into the filtered water was within safe limits, indicating no potential risk to human health. Home-based application tests further demonstrated stable performance and consistent water quality under continuous operation. Overall, the developed AgNPs-loaded filters represent an effective, low-cost, and practical solution for water disinfection, particularly in regions lacking advanced water treatment infrastructure.

ZnO is recognized as a wide-bandgap semiconductor (3.37 eV) possessing a relatively huge exciton binding power (~60 meV), which makes it highly attractive for optoelectronic technologies. According to the current study, Co-incorporated ZnO nanoparticles were fabricated through an economical sol-gel synthesis route. The structural and optic characteristics were comprehensively underwent examination using XRD, SEM, and UV-Vis methods. Diffraction results reveal that all synthesized samples retain a pure hexagonal wurtzite phase, with no evidence of secondary phases, confirming effective Co incorporation into the ZnO lattice. As the Co concentration increases, a slight reduction in crystallite size is observed, indicating lattice distortion induced by dopant atoms. SEM analysis shows that the particles are predominantly quasi-spherical with minor agglomeration, and doping does not significantly alter their morphology. From an optical perspective, increasing Co content causes the absorption edge to shift toward longer wavelengths, accompanied by stronger absorption in the visible region. Bandgap values, extracted using Tauc analysis, reduce from 3.18 eV (undoped ZnO) to 2.94 eV at 3 mol% Co, followed by a marginal increase at higher concentrations. This trend is associated with the introduction of impurity-related electronic states within the bandgap. Overall, Co incorporation provides an effective means to modulate the optical response of ZnO nanostructures, thereby enhancing their suitability for advanced optoelectronic applications.

This study used high-vacuum (10⁻⁵ Torr) thermal evaporation to fabricate a hybrid tellurium-tin/crystalline silicon (TeSn/c-Si) junction. The junction was deposited at room temperature, 323 K, and 348 K to evaluate its structural and electrical properties. Thin TeSn layers (500 nm thick) and the resulting diodes underwent thermal annealing. DC conductivity testing revealed a double-transfer mechanism governed by the Arrhenius equation. A significant increase in the activation energies Ea1 and Ea2 was observed following thermal annealing at 348 K, reaching 0.44 eV and 0.65 eV, respectively. This indicates an improvement in the layer’s crystallinity due to annealing and a decrease in the density of local states. Capacitance-voltage (C-V) measurements confirm the formation of a sharp heterojunction interface, exhibiting a significant improvement in the internal potential (Vbi) from 1.24 eV (at room temperature) to 1.7 eV (at 348 K) due to the passivation of the interface states. Furthermore, the current-voltage (I-V) characteristics in darkness show thermal emission behavior under forward bias and a gradual breakdown under reverse bias. Under illumination, the heterojunction exhibited a significant improvement in photovoltaic performance, with a peak short-circuit current density (Jsc) of 3.1 × 10⁻¹ mA/cm² after annealing at 348 K. These results highlight the crucial role of post-deposition thermal tuning in reducing recombination centers and enhancing the overall efficiency of chalcogenide-based solar harvesting devices.

This study investigates carrier recombination dynamics in InGaN/GaN quantum wells using time-resolved techniques, including induced grating methods, time-resolved photoluminescence, and pump–probe spectroscopy. Diffusion and carrier lifetime dependency on excitation density is systematically analyzed for structures with varying indium compositions and barrier configurations. The results reveal that carrier lifetime decreases while diffusion coefficients increase with rising excitation density, indicating enhanced nonradiative recombination under high carrier concentrations. This behavior is more pronounced in samples with higher indium content, suggesting a strong influence of carrier localization. The experimental observations are interpreted using an extended ABC recombination model that incorporates carrier density–dependent recombination processes. The analysis demonstrates that defect-assisted recombination becomes dominant at high excitation levels, while Auger recombination remains negligible within the investigated carrier density range. Furthermore, pump–probe measurements confirm distinct recombination pathways associated with localized and delocalized carrier states. These findings provide important insights into the physical mechanisms governing carrier dynamics and performance droop in InGaN-based quantum well designs, offering guidance for the optimization of high-performance optoelectronic devices.