The assembly of nanoparticles into mesoscopic structures, known as Superparticles (SPs), leads to emergent properties arising from interactions among their components [1, 2]. Indeed, various types of nanoparticles, ranging from metal chalcogenide and perovskite quantum dots (QDs) to metal nanoparticles and magnetite nanocubes, can act as functional building blocks for artificial solids displaying unique properties that transcend those of their constituents. Within this landscape, SPs based on plasmonic metal nanoparticles [3-5] have attracted significant interest owing to the unique coupling effects between the plasmonic fields of the constituent nanoparticles, holding great promise for several applications including ultra-efficient surface-enhanced Raman scattering (SERS) [6,7]. Despite this promising outlook, the understanding of the fundamental factors driving the behavior of metal SPs is still incomplete.

Here, we assembled gold nanoparticles (AuNPs) into 200-300 nm SPs with varying interparticle distances. After performing a structural characterization of the resulting SPs, we leveraged transient absorption spectroscopy (TA) and transient absorption microscopy (μPP) to unravel their ultrafast photophysics. Our results shed light on the role of interactions between plasmon resonances in determining the overall optical response of metal SPs. In fact, both spectral shape and kinetics show a dependance upon the interparticle distance, revealing the emergence of a collective response of the SP to photoexcitation due to interactions between the constituent nanoparticles, as also highlighted by numerical field enhancement simulations. The results pave the way to the engineering of functional metal-based superstructures for a variety of possible applications in photonics and optoelectronics.

[1] ACS Nano 2020, 14, 10, 13806–13815.

[2] Nat Synth, 2023, 10.1038/s44160-023-00407-2.

[3] Chem. Rev. 2020, 120, 2, 464–525.

[4] Nanoscale Adv., 2020, 2, 3764-3787.

[5] Nat. Comm, 11, 2771, 2020.

[6] Adv. Funct. Mater. 2020, 30, 2005400.

[7] Nanoscale, 2019, 11, 17444-17459.

The increasing demand for compact, flexible, and transparent energy storage devices has stimulated intensive research on advanced electrode materials. Transition metal oxides are among the most promising candidates, with vanadium oxide (VOₓ) attracting particular interest due to its wide range of accessible oxidation states and ability to form non-stoichiometric phases. In this work, VOₓ thin films were prepared on ITO-coated glass substrates by DC reactive sputtering under different oxygen pressures, without applying external heating. Structural and optical characterization by SEM and UV-Vis spectroscopy confirmed the formation of smooth, uniform films with a thickness of about 100 nm and no detectable porosity. XPS analysis revealed that varying the oxygen pressure during deposition allows manipulation of the vanadium oxidation states, thereby tuning the electronic structure of the films. This adjustment in oxidation states directly influenced their electrochemical response. Electrochemical testing in 1 M Na₂SO₄ revealed excellent capacitive behavior: cyclic voltammetry showed a volumetric capacitance of 143 F/cm³ at 50 mV/s, while galvanostatic charge–discharge experiments demonstrated stable cycling at 1 mA/cm². These findings highlight reactive sputtering as a scalable method to produce VOₓ thin films with controlled structural and electronic properties. The observed correlation between oxidation state distribution and electrochemical behavior underscores their strong potential as electrodes for supercapacitor applications.

The pursuit of sustainable and lead-free alternatives for piezoelectric materials has motivated the development of new synthesis strategies with minimal environmental impact. In this study, we report an eco-friendly approach for fabricating piezoactive nanostructures based on zinc oxide (ZnO) doped with silver (Ag) and lithium (Li).

The nanostructures were synthesized via a low-temperature hydrothermal method directly on metallic substrates (platinum and titanium foils) previously coated with a ZnO seed layer obtained through sol–gel spin coating. The hybrid system was further encapsulated with a polymer layer to ensure mechanical stability and compatibility for device integration. Comprehensive morphological characterization was performed using atomic force microscopy and scanning electron microscopy, confirming the successful growth of well-aligned doped ZnO nanostructures. The piezoelectric performance of the samples was evaluated through measurements of the direct piezoelectric coefficient (d₃₃).

The results demonstrated that the incorporation of dopant ions not only preserved but also enhanced the piezoelectric activity of the ZnO structures, indicating that the synthesis route is both efficient and environmentally responsible. This work highlights the potential of Ag- and Li-doped ZnO nanostructures, prepared under green processing conditions, for obtaining large-area piezoelectric materials. The combination of low-cost synthesis, ecological benefits, and functional piezoelectric response suggests that this approach represents a promising pathway toward sustainable materials design for applications in energy harvesting.

Lead-free ferroelectric ceramics have gained widespread interest as alternatives to toxic lead-based dielectrics. In this work, Ba₀.₉₅Ca₀.₀₅TiO₃ (BCT) ceramics were synthesized via the conventional solid-state reaction route and evaluated for their structural and dielectric characteristics. X-ray diffraction combined with Rietveld refinement confirmed the formation of dense ceramics with a tetragonal perovskite structure (P4mm) after calcination at 850 °C and sintering at 950 °C, with refined lattice parameters a = 3.9895 Å, c = 4.0114 Å and c/a = 1.0055. The nanocrystalline microstructure remained stable, with an average crystallite size of ~26 nm and minimal lattice strain, demonstrating uniformity of the phase. Raman spectroscopy further supported the tetragonal symmetry through distinct E(TO) and A₁ vibrational modes, underlining the structural robustness of the synthesized ceramics. Dielectric investigations revealed a high permittivity of ~600 at 100 Hz and 50 °C, while a stable dielectric response was maintained between 10 kHz and 1 MHz across 100–450 °C. Importantly, dielectric loss remained below 0.1 throughout this operational range, confirming excellent thermal–frequency stability and low energy dissipation. Impedance and electric modulus analyses highlighted the presence of non-Debye type relaxation, defect-mediated hopping conduction, and clear distinction between grain and grain boundary contributions. The combination of phase purity, nanocrystalline stability, and superior dielectric response demonstrates the potential of BCT ceramics as environmentally benign candidates for next-generation capacitors, high-temperature sensors, actuators, and energy-storage devices.

Photoelectrocatalysis (PEC) is a promising solar-driven strategy that integrates photocatalysis and electrocatalysis for both solar fuel generation and water remediation. Among emerging contaminants, antibiotics and non-steroidal anti-inflammatory drugs are of particular concern due to their persistence and ecological risks. Tungsten trioxide (WO₃) is a benchmark n-type photoanode owing to its suitable band gap (~2.7 eV), strong oxidative potential, and acid stability. However, its relatively positive conduction band (~0.5 V vs. NHE) hampers O₂ reduction, limiting PEC degradation efficiency for pharmaceutical pollutants. Defect engineering via oxygen vacancies is an effective route to extend light absorption, enhance carrier mobility, and activate surface sites without complex modifications. In parallel, structuring metal oxides into three-dimensional inverse opals (IOs) produces ordered macroporous photonic crystals with tunable photonic band gaps (PBGs), where slow-photon effects can be integrated with suitable compositional modifications to improve light trapping and charge separation.

Here, we combine these two strategies in oxygen-deficient WO_3-x IO photoanodes for the PEC degradation of tetracycline (TC) and ibuprofen (IBU). PBG engineering was first optimized by tuning IO lattice constants relative to the absorption edge, as confirmed by photoelectrochemical tests and TC degradation performance. The best-performing IOs were subsequently reduced under H₂, introducing oxygen vacancies and W⁵⁺ defect states. The resulting WO_3-x IOs showed more than twofold photocurrent enhancement, extended visible–NIR absorption, and increased donor density. These oxygen-deficient IOs achieved significantly higher PEC degradation rates for both pollutants, validating the synergistic role of vacancy engineering and photonic structuring. This study highlights the potential of WO_3-x IOs as efficient photoanodes for solar-driven pharmaceutical degradation and establishes defect–photon coupling as a general strategy to advance PEC water treatment technologies.

Acknowledgements

The research work was supported by the Hellenic Foundation for Research and Innovation (HFRI) under the 3rd Call for HFRI PhD Fellowships (Fellowship Number: 5570).

Polyethylene terephthalate–derived fluorescent carbon quantum dots (PET-FCQDs) have emerged as promising nanomaterials for environmental sensing and potential biomedical applications. However, their biological safety profile remains underexplored, particularly when modified through metal doping for enhanced performance. In this study, we present a comprehensive in silico biocompatibility and safety evaluation of pristine and dual-site metal-doped PET-FCQDs (Ca, Mg, Zn, Fe) using multi-target molecular docking against key human proteins—Human Serum Albumin (HSA), Cytochrome P450 3A4 (CYP3A4), Hemoglobin, Transferrin, Caspase-3, Glutathione S-Transferase (GST), Estrogen Receptor alpha (ERα), and inflammatory markers (TNF-α, IL-6). The docking analysis revealed moderate to strong binding affinities, with variations in interaction profiles suggesting different implications for distribution, metabolism, and potential toxicity. Additionally, ADMET analysis indicated that all variants possessed high gastrointestinal absorption, low skin permeability, favorable blood-brain barrier penetration, and non-mutagenic, non-carcinogenic profiles. Metal doping enhanced aqueous solubility (up to ~18.6 mg/mL for Ca-O and Mg-O variants) but generally reduced lipophilicity (Log P: 0.38–0.64 vs. pristine: 1.13). All CQDs complied with major drug-likeness rules (Lipinski, Veber, Egan, Muegge) and displayed minimal CYP450 inhibition risk, indicating low potential for drug–drug interactions. Toxicity predictions classified all as low acute toxicity (Class III, LD₅₀ = 500–5000 mg/kg), with biodegradability dependent on doping site. These findings provide novel computational insights into the biocompatibility and pharmacokinetic behavior of PET-FCQDs and their doped analogues, supporting their safe integration in biomedical and environmental applications while highlighting site- and metal-dependent variations in safety profiles.

Stable high-spin organic radicals (S ≥ 1) are attractive objects for organic materials with potential applications in fields such as organic magnets, spintronics, spin filters, and memory devices [1]. However, the synthesis of thermally stable di- and polyradicals is a challenging task, especially when ferromagnetic exchange interactions between multiple paramagnetic centers are desired. The report discusses methods for obtaining promising synthetic blocks for the synthesis of functionally substituted di-nitronyl nitroxyl radicals and their complexes with Cu(hfac)2 based on m-xylene. Using the strategy of Pd-catalyzed cross-coupling reactions of active aryl halides based on 4,6-dibromoiso-phthalaldehyde, an approach to obtaining a new type of polyhetero-radicals is proposed. The structural features of the obtained paramagnets and their EPR spectra are considered. Recently, the bifunctional substituted nitronyl nitroxide (NNR) diradical which was synthesized by cross coupling reaction such as 1 which was successfully used as a working body in a molecular heat engine in the study of spin phase transitions between superconducting electrodes [2].

In this presentation and graphical abstract , various synthetic approaches to previously unknown types
of functionally substituted (X, Y = Br, NO2, COOR) diradicals 2, 3 with meta-positioning of the NHR fragments will be discussed. Special attention will be paid to methods of introducing reactive groups into the diradical molecule by using cross coupling reaction and the possibility of obtaining various complexes with copper salts.

References:
[1] E. V. Tretyakov, I. A. Zayakin, A. A. Dmitriev, M. V. Fedin et al. Chem. Eur. J. 2024, 30, e202303456.
[2] S. Volosheniuk, D. Bouwmeester, D. Vogel, H.S.J. van der Zant et al. Nat. Commun., 2025, 16, 3279.

Caffeine is one of the most popular bioactive substances and psychoactive agents in the world. Due to its stimulating properties and cognitive-enhancing abilities, it is a formulation staple in many beverages. Additionally, this alkaloid is known to support metabolic health. However, caffeine is rapidly absorbed and metabolized, which can limit its effectiveness throughout the body and increase the risk of side effects, including tachycardia, dependence, insomnia, and migraines, especially in highly sensitive individuals or when consumed in high doses. Materials science proves essential for this purpose. Following PRISMA guidelines, this systematic review discusses the latest advances in using nanomaterials to encapsulate caffeine in functional drinks. Results have shown that a feasible strategy to increase bioavailability, protect against gastric degradation, and enable controlled release in the intestine is to encapsulate caffeine in nano/microcarriers. These nanomaterials optimize absorption, preventing acute energy spikes and subsequent sharp declines. Furthermore, the liquid matrix of functional drinks, composed of macronutrients and micronutrients, can modulate the stability and release profile of nanosystems. The matrix also affects the interaction between the nanoparticles and the liquid environment, thereby influencing caffeine's final bioaccessibility. Therefore, understanding these interactions is essential to designing functional drinks that modulate caffeine release at the intestinal level. This approach increases the safety of caffeine intake and minimizes adverse effects caused by sudden spikes in plasma levels. Finally, using nanocarrier systems in liquid formulations can facilitate incorporating caffeine into sustained-release matrices with an improved sensory profile. This reduces the perceived bitterness by activating taste receptors in the oral mucosa, thereby enhancing consumer acceptance of the final product.

Zirconia (ZrO₂) is a ceramic oxide known for its properties such as inertness and biocompatibility, making it attractive for biomedical and protective coating applications.

In this study, Zirconia (ZrO₂) thin films were deposited using a radio-frequency magnetron sputtering (RFMS) system. A pure zirconium target was sputtered in an Ar–O₂ gas mixture. The sputtering power was systematically varied from 100 W to 400 W in order to investigate its influence on the film’s properties.

The structural, morphological and surface characteristics of the deposited films were analyzed using X-ray Diffraction, contact angle measurements and Atomic Force Microscopy. XRD results show that the monoclinic phase is predominant in lower sputtering power, and the increase in the power induces a notable change in the films' crystallinity and the preferred orientation. Higher sputtering power also led to a significance increase in the surface roughness (from 0.46 nm at 100 W to 14.77 nm at 400 W). In line with our previous work [1], in this study, the contact angle measurement showed that a sputtering power of 250 W produced the most hydrophobic films. In addition. The electrochemical behavior of the films was assessed trough potentiodynamic polarization tests in Hank’s solution. Compare to the uncoated sample, the films presented a better corrosion resistance. The results also showed that the Zirconia films exhibited a protective anti-corrosion performance.

In conclusion, the results demonstrate that the sputtering power is a key deposing parameter for tailoring different properties of zirconia thin films, confirming their potential as a protective coating for biomedical metals.

[1] H.Zegtouf et al , Influence of oxygen percentage on in vitro bioactivity of zirconia thin films obtained by RF magnetron sputtering, Applied Surface Science, V532, 2020, 147403, ISSN 0169-4332

Classical effective-medium models (e.g., Maxwell, Hamilton–Crosser) systematically underpredict thermal-conductivity enhancements in nanofluids and cannot reproduce the characteristic sublinear growth and early saturation seen across metal-oxide, graphene, and carbon-nanotube (CNT) dispersions. I present a compact mesoscale correction that augments a baseline effective-medium estimate with a single compound parameter representing interfacial layering and collective micro-scale coupling. In its simplest closed form:

κₑff / κₘ = 1 + α √φ

where κₑff is the effective thermal conductivity, κₘ the base-fluid conductivity, φ the particle volume fraction, and α one system-level parameter that can be estimated once from lightweight characterization proxies (e.g., viscosity ratio, ζ-potential, dynamic light scattering size) and then held fixed for prediction across concentrations. The √φ shape encodes two bundled effects: (i) a density-linked screening length in the interfacial layer that weakens with concentration, and (ii) a narrow resonance-like coupling window that briefly boosts transport before saturation.

Using small, public datasets (Al₂O₃/water, graphene/water, CNT/water, 20–40 °C, φ ≤ 6%), the one-parameter law reproduces curvature and saturation that classical models miss, while remaining falsifiable: once α is fixed from a single calibration point, all remaining concentrations are blind predictions. I provide a predict-then-make workflow—measure 2–3 proxies → estimate α → forecast κₑff before formulation—and a design chart linking target gain to particle size, volume fraction, and surfactant level.

The talk covers (i) derivation and physical interpretation; (ii) validation on held-out concentrations and particle types; (iii) a falsifier specifying data patterns that would refute the model; and (iv) guidance for synthesis/processing to hit required conductivity gains without extensive trial-and-error.