Introduction

Organic solar cells (OSCs) are attractive for low-cost, lightweight, and mechanically flexible photovoltaic technologies. However, their efficiency is limited by suboptimal light absorption and charge extraction. Incorporating an optical spacer, such as zinc oxide (ZnO), has been proposed to improve device performance by enhancing both optical and electrical responses.

Methods

Finite element method (FEM)-based simulations were carried out to examine the effect of a ZnO optical spacer in OSCs. The active layer consisted of a PTB7 donor blended with a PCBM acceptor. Two device structures were analyzed: a reference design (Glass/SiO₂/ITO/PEDOT:PSS/PTB7:PCBM/Al) and a modified configuration with a ZnO spacer inserted between the PEDOT:PSS layer and the active blend (Glass/SiO₂/ITO/PEDOT:PSS/ZnO/PTB7:PCBM/Al). Optical field distribution, exciton generation rate (G), and short-circuit current density (JSC) were evaluated under monochromatic illumination (450–850 nm) and standard AM1.5 solar conditions at 100 mW/cm².

Results

The inclusion of ZnO significantly enhanced the internal electric field distribution and increased exciton generation across the active layer. This improvement is attributed to the dual role of ZnO: (i) its optical spacer effect, which reduces reflection losses at the PEDOT:PSS/active interface and redistributes light more effectively within the absorber, and (ii) its favorable electronic properties, which facilitate electron transport and mitigate interfacial recombination. Under AM1.5 illumination, the ZnO-modified structure exhibited nearly 30% higher light absorption and a notable increase in JSC compared to the reference cell.

Conclusion

This numerical study demonstrates that integrating a ZnO spacer layer into OSCs simultaneously improves light harvesting and charge extraction. The findings, in agreement with experimental reports, confirm the multifunctional role of ZnO as both an optical spacer and an electron-transporting interfacial layer, providing a practical strategy for enhancing the efficiency of organic photovoltaics.

Introduction: Water contamination by synthetic dyes from industrial effluents presents a severe threat to ecosystems and public health. There is a critical need for the development of efficient, sustainable, and easily separable adsorbents to remove these pollutants. This study focuses on synthesizing and evaluating a novel magnetic nanocomposite adsorbent that combines the high adsorption capacity of graphene oxide (GO) with the magnetic properties of nickel ferrite for the effective removal of dye pollutants from wastewater.

Methods: Magnetic M-type nickel ferrite (NiFe₁₉O₂₀) nanoparticles were first synthesized via a combustion method. Subsequently, composite nanofibers were fabricated by incorporating these nanoparticles and graphene oxide (GO) nanosheets into a polymer matrix using the electrospinning technique. The resulting NiFe₁₉O₂₀/GO composite nanofibers were thoroughly characterized using SEM, TEM, XRD, FT-IR, and VSM. Their adsorption performance was evaluated using Methylene Blue (MB) as a model cationic dye.

Results: The characterization results confirmed the successful integration of NiFe₁₉O₂₀ nanoparticles and GO nanosheets within the nanofiber matrix. The composite exhibited excellent superparamagnetic properties, allowing for rapid separation from water using an external magnet.

Conclusions: The NiFe₁₉O₂₀/GO composite nanofibers successfully combine the exceptional adsorption capacity of GO, provided by its high surface area and functional groups, with the superb magnetic separability of nickel ferrite. This study conclusively demonstrates that this material is a highly effective, reusable, and easily retrievable adsorbent. It presents a promising and sustainable solution for the advanced treatment of dye-laden wastewater, offering significant potential for environmental remediation applications.

Introduction

Conductive polymers, particularly polyaniline (PANI), are crucial in materials science, but their application is often limited by the use of corrosive mineral acids like HCl for doping. This study investigates the use of oxalic acid, a safer organic acid, as a functional dopant to create an environmentally benign and more processable form of PANI.

Methods

Polyaniline was synthesized and doped separately with hydrochloric acid (PANI-HCl) and oxalic acid (PANI-OA). The resulting materials were comprehensively characterized using FTIR and UV-Vis spectroscopy, Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), four-point probe conductivity measurements, and qualitative solubility tests.

Results

FTIR analysis confirmed the successful doping of PANI with oxalic acid, evidenced by significant shifts in the benzenoid and quinoid ring stretching vibrations and an enhanced band at ~1158 cm⁻¹, indicating charge delocalization. Furthermore, SEM imaging revealed a significant morphological transformation from a classic "cauliflower-like" structure in PANI-HCl to an ordered "rod-like" microstructure in PANI-OA. This structural change was accompanied by a trade-off in performance where PANI-OA exhibited lower electrical conductivity (1.23 S/cm) and reduced thermal stability compared to PANI-HCl (329 S/cm). However, these drawbacks were offset by a critical gain in processability, as PANI-OA demonstrated excellent solubility in polar aprotic solvents, whereas PANI-HCl remained intractable.

Conclusion

Doping polyaniline with oxalic acid sacrifices conductivity and thermal stability for major gains in processability, safety, and morphological control. This work validates the use of functional organic dopants to engineer task-specific conductive polymers with tailored properties for solution-based fabrication.

Introduction.

The need for decarbonization in the chemical industry has stimulated active research for novel methods that can synthesize ammonia, which is a key part of the production of fertilizers and a promising hydrogen carrier. The electrochemical reduction of nitrite (NO₂^–RR) is of particular interest, as this will make it possible not only to obtain a valuable product, but also to solve the problem of wastewater treatment from nitrogen pollution. Our studies demonstrate that intermetallic compounds (IMCs) open up new possibilities for creating highly efficient catalytic systems. In this work, studies were conducted on the use of CuSi-containing IMCs as catalysts in the NO₂^–RR reaction.

Experimental Section.

The samples CuSi-IMC were prepared using arc melting in an argon atmosphere at the AM-200 facility. Mass control of the samples after fusion showed that melting losses did not exceed 1 mass%. Physicochemical characterization methods, such as SEM and XRD, were used for CuSi-IMC samples. Voltammetry and chronoamperometry were used to determine the conditions for the synthesis reactions of ammonia using Autolab PGSTAT302N and PS-20 potentiostats.

Results and Discussion.

The results show that the use of CuSi-IMC electrocatalysts is promising, since excellent values of Faradaic efficiency (FE) and ammonia yield rate were achieved in the NO₂^–RR. Moreover, IMC-based catalysts show higher results at lower potentials than just solid solution catalysts.

Acknowledgment.

The research was carried out at the expense of a grant from the Russian Science Foundation (RSF) No 25-29-00488, https://rscf.ru/en/project/25-29-00488/.

Expansive clay soils are known for their low strength and high compressibility, which often lead to severe geotechnical challenges in construction. This study evaluates the combined effects of lime, nano-metakaolin (NMK), and sisal fibre on the strength and consolidation behavior of expansive clay. Lime content was maintained at 4%, while NMK was varied at 4, 8, and 12%, and sisal fibre was incorporated at 2, 3, 4, and 5% by dry weight of soil. A series of laboratory tests, including unconfined compressive strength (UCS) and one-dimensional consolidation tests, were conducted to determine the mechanical and compressibility characteristics of the treated soils. The results indicate that the inclusion of NMK significantly enhanced pozzolanic reactivity with lime, leading to improved soil bonding and higher UCS values. The addition of sisal fibre provided tensile bridging within the soil matrix, which increased ductility and contributed to sustained strength at higher fibre dosages. In terms of consolidation, the treated specimens showed reduced compressibility and lower coefficient of consolidation compared with untreated expansive clay, reflecting the densification and pore-filling effects of lime–NMK reactions and fibre interlocking. The optimum performance was observed at intermediate NMK contents (8%) and fibre reinforcement of 3–4%, where a balance between strength gain and reduced compressibility was achieved. Overall, the study demonstrates that a combination of lime, NMK, and sisal fibre provides a sustainable and effective technique for improving the strength and consolidation properties of expansive soils, with promising applications in geotechnical engineering practice

Introduction
Gold nanoshells (AuNSs) with dielectric cores have emerged as promising agents for biomedical photothermal therapy due to their tunable plasmonic properties in the near-infrared region. Understanding their thermal responses under various laser excitations is crucial for optimizing their therapeutic efficiency and safety.

Methods
We employed finite element modeling (FEM) in COMSOL Multiphysics to investigate the spatiotemporal temperature evolution of SiO₂@Au and BaTiO₃@Au nanoshells, as well as nanobars, under continuous-wave (CW), nanosecond (ns), and femtosecond (fs) laser irradiation. The models coupled electromagnetic absorption with heat transfer, accounting for electron–phonon and phonon–environment interactions through one-, two-, and three-temperature models depending on the pulse duration.

Results
Our simulations show that BaTiO₃@Au nanoshells exhibit significantly higher absorption and heating than SiO₂@Au, particularly at 800 nm, a wavelength relevant for biomedical applications. Under CW excitation, the temperature rise is moderate and spatially uniform, reaching equilibrium within hundreds of nanoseconds. In contrast, ns pulses produced localized heating with delayed peak temperatures (~203 K for BaTiO₃@Au vs ~34 K for SiO₂@Au at 5 mJ/cm²), while fs pulses induced ultrafast electron heating (>3000 K) followed by energy transfer to the lattice and environment within a few nanoseconds. Parametric studies revealed a strong dependence of the thermal response on shell thickness, pulse duration, and fluence.

Conclusion
This work highlights the distinct thermal dynamics of gold nanoshells under different irradiation regimes and identifies BaTiO₃@Au as a highly efficient photothermal agent. These insights provide valuable guidance for designing nanoshell-assisted cancer therapies with controlled heating and minimal collateral damage.

The integration of modular container for Onshore Power Supply (OPS) systems for electric boats presents a strategic advancement in sustainable maritime infrastructures which are under-developed. This study explores the design and production of lightweight, modular containers made using composite sandwich panels with basalt fibre skins, extruded polystyrene (XPS) cores, and epoxy resin matrices. The sandwich panel production process uses one-shot vacuum infusion, ensuring uniform resin distribution and minimized void content. Basalt fibre, known for its high tensile strength, thermal stability, and resistance to corrosion, offers a sustainable alternative to conventional synthetic fibres. Combined with XPS, which contributes thermal insulation and low density, the resulting sandwich structure achieves an optimal balance between weight reduction and mechanical performance. These modular units are tailored to meet the general operational demands, providing adaptable, durable storage and systems housing. Experimental tests confirm the composites’ favourable strength-to-weight ratio and environmental resilience, highlighting their suitability for marine applications. Furthermore, the modularity supports scalability and ease of maintenance, aligning with the dynamic logistical needs of modern electric boat operations. This research underscores the potential of advanced composite manufacturing techniques in maritime applications, contributing to the broader objectives of energy efficiency, operational flexibility, and sustainable design in the naval sector.

Semiconductors are fundamental components of modern industry, as they serve as the backbone of electronics and energy technologies. Among their many characteristics, thermal properties play a crucial role in ensuring both performance and long-term reliability. Doped semiconductors, in particular, display unique and useful electronic properties; however, the introduction of impurities generally alters their thermal behavior, often leading to a reduction in thermal conductivity. To study this effect, equilibrium molecular dynamics (EMD) combined with the Green–Kubo formalism can be employed to calculate the thermal conductivity of doped semiconductor systems. In addition, the use of interatomic potentials, such as the Tersoff model, provides a framework to capture the underlying atomic interactions. By integrating machine learning techniques with molecular dynamics, it becomes possible to predict thermal properties across different doping levels and defect concentrations. Machine learning models, trained on simulation data, can reduce the computational cost of traditional simulations, which are typically both time- and resource-intensive. The results highlight how doping and defects modify thermal conductivity and help establish practical limits for impurity levels that still allow semiconductors to remain attractive for technological applications. The results are also of interest to determine the figure of merit of doped semiconductors. Understanding this relationship is essential for designing advanced materials that balance performance, efficiency, and reliability.

The development of advanced energy harvesting technologies requires piezoelectric architectures that combine high efficiency with mechanical flexibility. In this study, we conduct a comparative investigation of zinc oxide (ZnO) nanowires (NW) arrays grown on rigid Au/Pt-coated substrates and on flexible titanium foils, with the aim of evaluating their potential for integration into next-generation piezoelectric devices.

Vertically aligned ZnO NWs were grown via a low-temperature hydrothermal process on a crystalline seed layer prepared by sol–gel spin deposition. To enhance structural integrity and device compatibility, the NW arrays were encapsulated within a polymethylmethacrylate polymer matrix. The nanostructures were characterized throughout fabrication using transmission electron microscopy, scanning electron microscopy, and spectroscopic ellipsometry, confirming uniform morphology, high crystallinity, and consistent alignment. Piezoelectric properties were directly evaluated by measurements of the effective longitudinal piezoelectric coefficient (d₃₃), enabling a quantitative comparison between rigid and flexible device platforms. The results revealed a significant enhancement in piezoelectric performance for ZnO NWs integrated on titanium foil compared to those grown on Pt/Au substrates. This improvement is attributed to superior vertical integration and enhanced mechanical adaptability of the NWs when supported by a flexible substrate. These findings highlight the critical role of substrate choice in optimizing nanoscale piezoelectric performance. Moreover, the demonstrated low-cost, solution-processed growth of ZnO NWs on flexible metal foils underscores their potential for scalable fabrication of energy harvesting systems.

These results indicate that solution-processed ZnO nanowires networks on metal foils provide a cost-effective, scalable pathway to developing efficient, environmentally sustainable energy harvesting devices.

The rising incidence of fungal infections and the limited effectiveness of current antifungal drugs emphasize the need for new active substances. Cryptococcus neoformans is a major opportunistic pathogen, responsible for cryptococcal meningitis in immunocompromised patients and associated with high mortality worldwide. Thiosemicarbazones and their metal complexes are reported to exhibit diverse biological activities, including antifungal effects.

For our study, we have synthesized 3-(morpholin-4-yl)propane-2,3-dione 4-phenylthiosemicarbazone (HL) and its mixed ligand–copper(II) complexes [CuL(Im)NO₃], [CuL(Py)NO₃], [CuL(β-Pic)NO₃], and [CuL(γ-Pic)NO₃]. The composition and structure of all compounds were confirmed using ¹H and ¹³C NMR, FTIR, elemental analysis, molar conductivity measurements, and X-ray crystallographic analysis.

The antifungal activity of all synthesized compounds was evaluated towards Cryptococcus neoformans (CECT 1043) using the broth microdilution method. The mixed ligand–copper(II) complexes exhibited higher activity compared to both the HL and the copper(II) nitrate complex from which they were obtained. This finding confirms that the introduction of an additional ligand into the inner coordination sphere can enhance biological activity. The most active compound was [CuL(γ-Pic)NO₃], which showed MIC and MBC values of 7.81 µg/mL and 15.63 µg/mL, respectively.

These results highlight the potential of mixed ligand–copper(II) complexes as promising leads for the development of new antifungal agents, particularly against pathogenic fungi such as Cryptococcus neoformans.

The work was performed with financial support from subprogram 010602 of the institutional project.