Alkaline earth copper silicates, with the general formula ACuSi4​O₁₀​ (A: Ca²⁺, Ba²⁺), are materials of historical relevance, known since ancient times. Notable examples are CaCuSi4​O₁₀​ (Egyptian Blue) and BaCuSi4​O₁₀​ (Han Blue), dating back to 2500 BC and 1200 BC respectively, both valued for their vibrant blue color and remarkable resistance to wear over time. In addition to their historical value, their unique layered crystalline structure and their ability to emit light in the NIR region make them promising candidates for optoelectronics. Their intense pigmentation is due to a chromophore center with a square planar [CuO₄​] group, surrounded by [SiO₄​] tetrahedra.

Although these are excellent optoelectronic materials, the literature lacks procedures for synthesizing a nanomaterial with good dimensional homogeneity. Current studies focus on exfoliating pre-formed bulk materials. A further advantage is their very low toxicity and biocompatibility, a rare quality for materials used in solar-to-electricity conversion, IR light-emitting devices, and telecommunications.

In this work, we present our recent results on the synthesis of 2D nanosheets of these two compounds and of SrCuSi4​O₁₀​. By modifying the reagents of the hydrothermal synthesis and the exfoliation conditions, it was possible to alter the final compounds obtained. Varied morphologies have been obtained: nanosheets, rolled nanosheets, and spheres. Depending on the different solvents used to exfoliate the samples, they undergo preferential exfoliation along different planes, resulting in a consequent variation in the relative intensity of the XRD pattern. The study on the influence of these multiple factors on NIR emission is currently underway.

Our study focuses on persistent luminescence (PeL) halide double perovskites (HDPs), both bulk and nano. PeL materials, or glow-in-the-dark materials, can temporarily store the excitation energy in metastable traps and release it as photons after a certain time. Given the same stoichiometry (Cs₂Na₁₋ₓAgₓInCl₆:Mn²⁺), at room temperature (RT) bulk shows PeL, but nano does not. The mechanism behind this behaviour is still unknown. To understand what causes the PeL annihilation at nano size at RT, we performed thermally stimulated luminescence measurements across a broad temperature range (10 K – 450 K) and PeL decay measurements (at RT and 15 K) after X-ray charge. These measurements enabled us to determine at which temperatures the materials exhibit PeL. At 15 K, even nano materials have PeL. So, to find out what causes the PeL behaviour change with T, we analysed electronic structure with T, using X-ray Absorption Near Edge Structure (XANES) spectroscopy at the K-edge of Mn (the emissive centre) at three different temperatures: 15 K (nano and bulk have PeL), 290 K (bulk has PeL) and 430 K (no PeL). The XANES analysis suggests that Mn is present in the bulk sample in both 2⁺ and 3⁺ oxidation states, but in the nano sample only 2⁺, so the PeL arising could be associated with the presence of the 3⁺ oxidation state.

The rise of antimicrobial resistance (AMR) poses a critical challenge to global health as conventional antibacterial drugs increasingly lose their efficacy. The administration of conventional antibacterial drugs often suffers from incomplete absorption, resulting in reduced efficacy and the need for higher or more frequent dosing. To counteract this limitation, a zinc-aluminium double hydroxide-palmitic acid nanocomposite (ZnAl-LDH-PA) was developed as a pH-reactive carrier for controlled drug delivery. The ZnAl-LDH-PA nanocomposite was synthesised using the co-precipitation method. Structural characterisation confirmed the successful intercalation: Powder X-ray diffraction (PXRD) showed an increase in the basal spacing from 8.6 Å to 14.35 Å, while Fourier transform infrared spectroscopy (FTIR) confirmed the intercalation by the disappearance of the nitrate band at 1344 cm-¹, the appearance of a COO band at 1535 cm^-¹ and the appearance of symmetric and asymmetric alkane stretching peaks at 2915 cm^-¹ and 2847 cm^-¹. Energy dispersive X-ray analysis (EDX) confirmed the incorporation of PA, with nitrogen absent and carbon making up 71.90% of the elemental composition. In addition, Brunauer–Emmett–Teller (BET) surface area measurements increased from 4.82 m²/g for the LDH host to 21.35 m²/g after intercalation, indicating improved porosity. Drug release studies showed a pH-dependent behaviour, with the highest release efficiency (68%) observed at a pH of 4.8, while a slower sustained release behaviour was observed at a pH of 7.4. The ZnAl-LDH-PA nanocomposite exhibited remarkable antimicrobial activity and retained the efficacy of palmitic acid against Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. Overall, the results show that ZnAl-LDH-PA nanocomposites are promising candidates for smart pH-responsive drug delivery systems. This work contributes to the further development of nanostructured carriers in pharmaceutical applications and provides a basis for further research into drug delivery.

Nanoparticles have become more widely applied in industrial, consumer, and therapeutic products since the past decade, and this trend is presumed to persist due to the rapid population growth, industry, urbanization, and intensive agriculture. The manufacturing of nanomaterials is not necessarily accomplished through eco-friendly processes. Certain nanomaterials involve heavy metals like, but not exclusively, mercury (Hg), platinum (Pt), palladium (Pd), cadmium (Cd), and lead (Pb). The releasing of nanomaterials into the environment could result in soil and aquatic system contamination. These problems have stimulated intensive research aimed at the prediction of environmental concentrations of nanoparticles in water and soil and at the determination of threshold concentrations for their ecotoxicological effect on aquatic and terrestrial ecosystems. Different studies show that metal-based nanoparticles with properties like hydrophilicity and low solubility impact the environment by creating toxics for the aquatic and terrestrial biota. Like ZnO Nanoparticles produce more toxicity due to their rapid dissolving nature. Semiconductor quantum dots based on cadmium selenide release ionic cadmium, resulting in exceeding water quality guidelines. and Ag nanoparticles disrupt membrane transport in algal species and higher organisms, causing adsorption and ingestion as it releases through oxidation. On the other hand, some nanomaterials benefit from geotechnical applications, like carbon nanotubes for soil reinforcement, nano bentonite for improving drilling fluids, and colloidal silica or laponite for mitigating soil liquefaction. Furthermore, this paper deals with current research on these competing roles, examining the causes of nanotoxicity as well as their positive geotechnical and remedial applications in water and soil systems. Furthermore, this study deals with the applications of different nanomaterials in water and soil systems and their subsequent impacts. It provides a general evaluation of the beneficial and harmful roles of these nanomaterials in water and soil systems for understanding the relationship between nanotechnology and the environment.

Introduction: Organic selenium plays vital roles in antioxidant defense, immune regulation, thyroid balance, and reproductive health. Selenium nanoparticles (SeNPs) have emerged as safer, more effective alternatives to bulk selenium due to their reduced toxicity and enhanced bioactivity arising from a high surface-to-volume ratio. While most studies focus on conventional synthesis, this work introduces a novel approach by applying ultraviolet (UV) irradiation, UVC (254 nm), and UVA (365 nm) to investigate how photonic treatment modulates SeNP characteristics.

Methods: SeNPs were synthesized by reducing 400 µL of 0.001 M selenomethionine with 30 mL of 0.001 M NaBH₄ under ice-bath stirring (500 rpm, 20 min), followed by dropwise addition (~1 drop/s). The suspensions were divided into three groups: non-irradiated control (S1), UVC-exposed (S2), and UVA-exposed (S3), each irradiated for 20 min at a distance of 10–15 cm. Characterisation was performed immediately using UV–Vis spectroscopy (200–800 nm, Thermo INSIGHT™ 2 software, Thermo Fisher Scientific, USA), diffuse reflectance analysis, and dynamic light scattering (DLS) with zeta potential (25 °C, Zetasizer Nano ZS).

Results: UV–Vis spectra showed broad SeNP absorption between 220 and 400 nm. Baseline absorbance increased from ~0.10 (control) to ~0.28 A.U. after UVC exposure and decreased to ~0.05 A.U. after UVA. Diffuse reflectance declined from ~95–100% in controls to ~60–70% with UVC and ~80–85% with UVA, confirming wavelength-dependent optical modulation. DLS revealed particle sizes of 40–90 nm for S1, 50–100 nm for S2 (mild aggregation), and 45–110 nm for S3 (greater polydispersity).

Conclusion: UV irradiation significantly modulated the optical and size properties of SeNPs without compromising colloidal stability. UVC exposure promoted mild aggregation, whereas UVA increased polydispersity, highlighting photonic modulation as a tunable strategy to optimise SeNPs for biomedical applications.

The birch wood industry is a key component of Latvia’s forest-based economy and presents significant potential for biorefinery innovations aligned with sustainability goals. This study proposes an integrated biorefining process for birch wood and lignocellulosic (LC) residues that enhances the preservation of cellulose while maximizing the yield of value-added chemical intermediates, specifically furfural and acetic acid. Traditional furfural production processes, which typically rely on sulfuric acid (H₂SO₄) catalysis, suffer from major drawbacks, including high cellulose degradation rates (40–50%) and the generation of environmentally hazardous sulfur-containing residues. In response, a novel pretreatment method using phosphoric acid (H₃PO₄) as a catalyst was developed to enable selective furfural extraction with significantly reduced cellulose loss. The integration of this process with downstream production of 5-hydroxymethylfurfural (5-HMF) offers a promising biorefining platform. The chemical composition of raw LC material and post-treatment residues was analyzed using NREL protocols (TP-510-42618, TP-510-42622) and HPLC. Process optimization was conducted using DesignExpert11 software across 26 experimental trials. Fixed parameters included raw material moisture content (45%) and H₃PO₄ concentration (55%), while catalyst amount, reaction temperature, time, and water steam flow were varied. The optimized process achieved a maximum furfural yield of 10.11% based on oven-dry mass (o.d.m.), corresponding to 65.67% of the theoretical maximum—substantially outperforming the 50–55% yields typically reported in industrial settings. Acetic acid yield reached 5.71%, while glucose loss in the LC residue was limited to 8.89%. Further optimization at Technology Readiness TRL6 reduced glucose loss to just 2.00%.

These findings demonstrate the feasibility and industrial relevance of a sustainable, integrated biorefining approach that maximizes chemical recovery while preserving carbohydrate value, supporting future developments in green chemistry and circular bioeconomy systems.

Funding: This research was funded by the Latvian Council of Science State Research Program: “Innovation in Forest Management and Value Chain for Latvia’s Growth: New Forest Services, Products and Technologies” (Forest4LV), project No VPP-ZM-VRIIILA-2024/2-0002

Soft, flexible and conductive silicone composites reinforced with carbon nanotubes (CNTs) are widely used in the field of (opto)electronics and (bio)medicine [1]. Usually, non-modified carbon fillers demonstrate poor distribution in polymer matrices resulting in the deterioration of composite properties. In order to obtain high-performance materials and devices, the surface of carbon filler can be functionalized with polymers. Among polymers, ferrocenyl-containing polysiloxanes can be used due to the unique properties of polysiloxanes, their ability to interact with the CNT surface as well as the presence of redox-active moieties allowing the use of the resulting material for sensing technologies, energy storage devices, etc. [2].

Thus, we used two different approaches to functionalize CNT with ferrocenyl-containing polysiloxanes. In this study, ferrocenyl-containing (poly)siloxanes bearing 100 mol.% of ferrocenyl groups were grafted to the CNT surface via the covalent ligand exchange reaction. Simultaneously the CNT was modified using a non-covalent approach and the synergistic interaction of ferrocenyl-containing polysiloxanes and CNT. The successful modification of CNT was confirmed using Raman and X-ray photoelectron spectroscopy. The modified CNTs were used as filler for soft, flexible and conductive silicone composites. The level of specific resistivity in the obtained composites was measured using broadband dielectric spectroscopy [2,3].

This study was supported by the Russian Science Foundation (project 24-13-00038).

The pursuit of high-energy-density cathode materials has positioned LiNiO₂ as a promising candidate due to its high theoretical capacity. However, its practical application is hindered by structural instability, cation mixing, and sluggish Li-ion mobility. This study presents a strategic co-doping approach to enhance the electrochemical performance of R3m-structured LiNiO₂ by introducing Na at the Li site and Nb/Al at the Ni site. First-principles calculations based on density functional theory (DFT), combined with the bond valence sum energy (BVSE) method, were employed to evaluate the structural, electronic, and transport properties of the doped systems. The optimized lattice parameters reveal that co-doping induces lattice expansion and suppresses cation disorder, thereby improving structural integrity. Band structure analysis indicates a reduced band gap in the co-doped configurations, suggesting enhanced electronic conductivity. Bader charge analysis confirms charge redistribution between dopants and host atoms, which stabilizes Ni oxidation states and mitigates Jahn–Teller distortion. Formation energy and phonon dispersion calculations validate the thermodynamic and dynamic stability of the modified structures. Furthermore, BVSE-based ion migration mapping shows that Na/Nb and Na/Al co-doping significantly broadens Li-ion diffusion pathways and lowers migration barriers compared to pristine LiNiO₂. These results demonstrate that dual-site doping is an effective strategy to overcome intrinsic limitations of Ni-rich layered oxides, offering a rational design route for next-generation Li-ion battery cathodes with improved cycling stability and rate capability.

This study aimed to apply the distribution of relaxation times (DRT) analysis on impedance spectra to model the electrochemical circuit of the electrode’s surface and reveal information about charge transfer, mass transport, and surface kinetics. A Cu-BTC metal–organic framework was synthesized and mixed with graphite to create a semiconductor layer on top of a glassy carbon electrode (GCE). Electrochemical impedance spectroscopy was applied to determine the effect of Cu-BTC thickness and Cu-BTC@Graphite mixing ratio, both compressed onto a graphite electrode. Cu-BTC acts as an insulator, thus it greatly reduces the conductivity of the electrode. An optimal ratio is observed at 60% Cu-BTC@Graphite. Cu-BTC@Graphite in a polymer mixture was drop-casted onto the GCE. Gold nanoparticles were electrodeposited, and the thiolated aptamer was immobilized via the Au-S bond formation. The impedance spectra were obtained for the hybrid nanomaterial electrode assembly. DRT plots were generated using pyDRTtools, showing 4-5 characteristic peaks from bare GCE to 3 characteristic peaks after modification. The Python package “Impedance.py” was used to fit the EIS data to each proposed equivalent circuit model (ECM) for the final assembly. Out of the six proposed ECMs, the Randles circuit with constant phase element (CPE) and a custom circuit with transmission line model (TLM) showed the best fit with root mean square error of 11.0 and 8.0, respectively. TLM applies to porous electrodes with high surface area, while the CPE accounts for the non-ideal capacitive behavior of the double layer, which is common in most biosensors.

Quantum dots (QDs) are three-dimensionally confined semiconductor nanoparticles that have been extensively studied to meet the demands of modern applications. Among them, core/shell QDs have emerged as highly versatile nanostructures that integrate quantum confinement with engineered band alignment, offering superior optical stability, high quantum yield, and reduced nonradiative losses compared to bare QDs. Beyond chemical stability, the shape, size, and surface modifications of core/shell QDs critically influence their optical and electronic properties, thereby governing effective carrier confinement. By spatially separating the optically active core from a passivating or electronically engineered shell, core/shell architectures suppress surface trap-mediated nonradiative recombination and spectral diffusion, resulting in higher quantum yields, improved photostability, and tunable band alignments for charge and exciton confinement. These attributes position core/shell QDs as promising materials for next-generation technologies.

Two parallel approaches currently dominate technological progress. First, epitaxial self-assembled III–V core/shell heterostructures (e.g., InAs/InP, GaAs/AlGaAs variants) yield optically active, spin-addressable single QDs with steadily improving coherence and deterministic coupling to photonic cavities—key advances that enable single-photon sources and spin-qubit prototypes, with coherence times now reaching microseconds to milliseconds under optimized decoupling and material-growth strategies. Second, colloidal core/shell QDs (e.g., graded-alloy CdSe/CdS/ZnS and perovskite core/shell systems) provide solution processability, high brightness, and tunable band structures that support on-chip integration and scalable quantum-emitter arrays, though challenges remain in minimizing charge leakage and noise as well as enhancing surface/ligand stability.

In summary, core/shell quantum dots combine material-level strategies (band engineering, shell passivation) with device-level integration (cavities, photonic circuits) to provide a practical pathway toward scalable quantum emitters and spin qubits. Ongoing progress in growth chemistry, decoherence suppression, and heterogeneous integration will play a decisive role in shaping their impact on near-term quantum computing and quantum communication technologies.