National Institute Of Materials Physics - Romania

Multilayer oxide/metal/oxide (OMO) structures emerge as suitable alternative to indium tin oxide (ITO) in transparent conductive electrode (TCE) field mainly due to their high visible light transmittance and low resistivity. Moreover, OMO structures are appropriate for flexible organic optoelectronic devices being less susceptible to cracking than single-layer ITO electrodes. Therefore, the present study is focused on the assessment of the properties of ZnO/Ag/ZnO (ZAZ) structures deposited by consecutive radio frequency magnetron sputtering (ZnO) and thermal vacuum evaporation (Ag) on flexible substrates such as polyethylene terephthalate, polyethersulfone and flexible glass. Additionally, the ZAZ deposition was carried out on patterned polyethersulfone in order to evaluate the nanopatterning effect on the properties of the multilayer structures. For comparison, ZAZ structures were also deposited on rigid glass substrate, this being commonly used in optoelectronic devices. The optical and electrical measurements reveal that the roughness of the deposition substrate has a significant impact on the transmittance and sheet resistance of the ZAZ multilayers. Thus, the best performance in terms of transmittance at 550 nm wavelength (82.7%), sheet resistance (9.5 52/square) and figure of merit (15.75x10-3 52-1), correlated with the lowest roughness (2.3 nm), is achieved for the structure fabricated on flexible glass. The values of the TCE key parameters endorse the developed ZAZ structures for optoelectronic applications.

This paper reports about bulk heterojunctions layers containing azomethine oligomers based on carbazole (AzC) or triphenylamine (AzPA) donor and alkyl perylene diimide derivative (PTCDI-12C) acceptor blended in different weight ratios (1:2), (1:3) and (1:4), prepared by Matrix Assisted Pulsed Laser Evaporation (MAPLE) on flexible substrate of polyethylene terephthalate (PET) covered by ITO. The effect of the type of azomethine donor substituent group and mixed layer composition on the optical and electrical properties was investigated in correlation with the molecular aggregation particularities and surface topographical particularities of the layers.The strong absorption band between 400 and 650 nm was favored by the strong polarization interactions in the layers deposited by MAPLE from chloroform and the red shift of the UV-Vis absorption peaks of PTCDI-12C in the both types of bulk heterojunction layer confirmed the generation during the deposition mostly of J-aggregates, which are associated with the fluorescence emission.The correlation between the roughness, statistical analysis parameters obtained by height-to-height correlation function, grains shape and electrical behavior was analyzed. The samples prepared with AzC donor showed photoelectric behavior with the best parameters for AzC:PTCDI-12C in a weight ratio of (1:3), while the sample with AzPA:PTCDI-12C mixed layer showed an injection contact behavior with the best current (10(-4) A for voltage < 0.5 V) at a weight ratio of (1:2). Thus, the behavior of the heterostructures is affected by the type of azomethine: carbazole-azomethine can be potential candidates for optoelectronic applications while triphenylamine-azomethine for electronic application.[GRAPHICS].

The kidney is a major organ for xenobiotic detoxification and a primary target for nanoparticle (NPs)-induced toxicity. This study investigated oxidative stress responses and renal histopathological alterations in Helix aspersa after dietary exposure to nickel oxide (NiO), magnesium oxide (MgO), and their composite (NiO-MgO) nanoparticles. Snails were fed two NPs concentrations (1 and 2 mg. g(-1) feed) for four weeks. Oxidative stress was evaluated through the biomarkers glutathione (GSH), glutathione peroxidase (GPX), glutathione S-transferase (GST), and catalase (CAT), supported by multivariate statistics, response surface modeling (RSM), and interaction energy analysis. All treated groups exhibited statistically significant oxidative alterations (p <= 0.05, one-way ANOVA, Fisher's LSD), including elevated GSH levels and GPX activity, suppressed GST activity, and dose-dependent modulation of CAT activity. The overall toxicological impact was synthesized into a unified assessment using the Integrated Biomarker Response (IBR) index, which revealed a clear toxicity hierarchy: NiO-MgO composite > individual NPs. RSM revealed nonlinear, nanoparticle-specific effects: GSH showed strong synergism, GPX mild synergy, while GST and CAT displayed antagonistic behavior. Further modeling using the Interaction-Based Hypothesis (IBH) framework linked response surface coefficients to molecular binding affinities, showing strong molecular interactions for GST (-8.3 kcal mol(-)(1)) and CAT (-8.0 kcal mol(-)(1)), consistent with observed enzyme inhibition. Histopathological assessments confirmed progressive renal lesions aligned with biochemical responses. Overall, these findings demonstrate that NiO and MgO nanoparticles impair renal antioxidant defense in H. aspersa through complex non-additive interactions. The integrated methodological framework bridges biochemical and molecular levels, highlighting ecological and food safety concerns associated with terrestrial nanoparticle contamination.

Composites based on TiO2 and single-walled carbon nanotubes (SWCNTs), highly separated in semiconducting tubes (S-SWCNTs) and as a mixture of metallic and semiconducting tubes (M + S-SWCNTs), were obtained by the interaction in the solid state. This interaction induces a change in the size of TiO2 particles from 23.67 nm to 28.2 and 150 nm, respectively, accompanied by an increase in the disorder state of the graphitic lattice of SWCNTs. We demonstrate by UV-VIS spectroscopy that the best performance in terms of rhodamine 6G (Rh6G) photodegradation is obtained in the case of the TiO2/S-SWCNT composite. The highest values of the Rh6G photodegradation efficiency were equal to 92% for an S-SWCNT concentration in the photocatalyst mass of 10 wt% and 94% for a 0.1 mM Rh6G solution with a pH equal to 1. We demonstrate that an important role is played by the O2(center dot)- and (OH)-O-center dot species in the photodegradation mechanism of Rh6G. This study contributes to a better understanding of the role of metallic and semiconducting carbon nanotubes in the photocatalysis field, highlighting that composites based on semiconducting SWCNTs and semiconducting metallic oxides are those that contribute essentially to the removal of dyes by exposure to the light emitted by a halogen lamp.

Using solid-state interactions, composites based on molybdenum disulfide (MoS2), poly(ortho-toluidine) (POT), and reduced graphene oxide (RGO) were prepared. Raman scattering and FTIR spectroscopic studies have demonstrated that the interaction of the RGO and MoS2 sheets with the POT-emeraldine base state (EB) leads to composites composed of RGO sheets non-covalently functionalized with pseudo-protonic POT doped with MoS2 and RGO covalently functionalized with POT-leucoemeraldine salt (LS). An alternative way to prepare these composites is the solid-state interaction of the RGO and MoS2 sheets with the POT-emeraldine salt (ES), resulting in composites composed of RGO non-covalently functionalized with POT-salt having pseudo-protonic acidic entities doped with MoS2 and RGO covalently functionalized with POT-leucoemeraldine base (LB). Using UV-Vis spectroscopy, we demonstrate that the exposure of these composites to UV light in protic polar solvents leads to the generation of partially de-doped POT-LB and POT-ES. The features of the composites after light exposure, as well as their transformation to the salt state, are highlighted by surface-enhanced Raman scattering. This study contributes to better understanding of the properties of the composites based on MoS2, POT, and RGO, highlighting the need to avoid the exposure of composites dissolved in polar protic solvents to UV light.

Erythropoietin (EPO), a glycoprotein hormone conventionally associated with erythropoiesis, has emerged as a versatile macromolecule with substantial therapeutic potential in tissue engineering and regenerative medicine. Beyond its role in red blood cell production, EPO displays pleiotropic effects, including angiogenesis, neuroprotection, anti-apoptosis, immunomodulation, and cell survival, making it a suitable agent for tissue repair and regeneration. This review explores EPO's biological characteristics and its integration into tissue-engineered constructs through innovative approaches such as scaffold immobilization, hydrogel encapsulation, and genetically modified cells for localized delivery. EPO has shown remarkable efficacy in regenerating diverse tissues, including bone, cartilage, neural, cardiac, dental, and skin, and in promoting wound healing. Additionally, its applications extend to advanced fields such as organoid development, immune modulation, and cancer research, further highlighting its versatility. Nevertheless, challenges such as maintaining EPO's bioactivity, achieving controlled and sustained delivery, and mitigating systemic or off-target effects remain significant barriers. Furthermore, its dual role in cancer biology necessitates a deeper understanding of its effects on tumor growth and immunity. Future advances in biomaterials and precision medicine could optimize EPO-based delivery systems to enable personalized therapeutic solutions. EPO stands poised to revolutionize tissue engineering, thus bridging laboratory innovation and clinical applications.

Rapidly solidified Fe-Pd-based ferromagnetic shape memory alloy ribbons, modified with Mn or Ga additions, were produced and subjected to post-solidification heat treatments of varying duration to investigate the interplay between composition, surface characteristics, and functional properties. Surface morphology and wettability were evaluated alongside corrosion behavior, magnetic response, martensitic transformation, and in vitro cell adhesion. Corrosion performance was assessed through immersion and electrochemical techniques, providing insight into degradation kinetics. The results reveal a complex coupling between surface properties, corrosion resistance, and cell adhesion responses. Binary Fe-Pd ribbons exhibit moderately rough, homogeneous surfaces with stable Wenzel-type wetting, but limited electrochemical stability due to the reactivity of iron. Mncontaining ribbons display heterogeneous surface features and locally poor wettability after short heat treatments, leading to reduced corrosion resistance and degradation of magnetic and martensitic properties; nevertheless, they support favorable fibroblast adhesion. Prolonged annealing improves surface uniformity and wettability, while maintaining moderate corrosion resistance and good cell adhesion. Ga-containing ribbons show highly nonuniform topography combined with good hydrophilicity and the highest corrosion resistance, attributed to the formation of stable Ga-O protective products. Although corrosion effects are mitigated, partial suppression of magnetic and martensitic responses is observed. The findings highlight the potential of Fe-Pdbased ferromagnetic shape memory alloy ribbons as degradable biomedical substrates.

Carbon-based nanomaterials (CBNs), including carbon nanotubes (CNTs), fullerenes, and graphene (GN), have attracted significant attention due to their unique structural, electrical, mechanical, and biocompatible properties. Their high surface area, excellent biocompatibility, and tunable physicochemical characteristics enable a wide range of applications, particularly in biomedicine, electronics, energy storage, and optoelectronics. CNTs, with their tensile strength and electrical conductivity, have been extensively studied for tissue engineering, drug delivery, and supercapacitor electrode applications. Despite concerns over their biocompatibility and toxicity, surface functionalization has shown promise in improving their performance and safety. Similarly, fullerenes, owing to their closed-cage structures and high electron affinity, exhibit potent antioxidant and photodynamic therapy capabilities, making them suitable for cancer treatment and optoelectronic devices. GN's high surface area and charge mobility make it ideal for energy storage systems such as supercapacitors and lithium-ion batteries, although its agglomeration tendency limits its practical use unless modified. This work provides a narrative synthesis of recent advancements and practical limitations, outlining future directions for biomedical and technological applications.

beta-SiC nanostructures were synthesized and incorporated into polypropylene (PP) to obtain SiC/PP nanocomposites (1-10 wt%). Scanning Electron Microscopy (SEM) revealed mixed morphologies of SiC with relatively uniform distribution, but progressive agglomeration at higher loadings. Debye-Scherrer calculations indicated that the SiC crystallite size in the composites evolves non-monotonically from 2.01 to 51.32 nm as a function of filler concentration, reflecting a competition between heterogeneous nucleation, particle aggregation, and interfacial confinement. Ultraviolet-Visible (UV-Vis) spectroscopy demonstrated deep-UV absorption below similar to 230 nm and slight shifts of the direct band gap, with Eg varying in a narrow range between 5.82 and 5.98 eV across the SiC/PP nanocomposite materials (Eg(PP) = 5.88 eV, Eg(SiC) = 5.79 eV). Fourier Transform Infrared (FTIR) and Raman spectroscopy revealed the gradual reduction of PP-characteristic bands and the growth of Si-C vibrational signatures, accompanied by an increase in the PP beta-phase fraction, indicating effective interfacial interactions and beta-nucleation by beta-SiC. Dielectric spectroscopy revealed Maxwell-Wagner-Sillars relaxation and a loading-dependent decrease of the permittivity at 80 degrees C and log omega approximate to 5.75 from epsilon ' approximate to 8.12 (PP) to approximate to 5.3-4.9 for composites. similar to 3 wt% SiC/PP provides an optimal compromise between dispersion, crystallinity, optical, and dielectric properties, making these nanocomposites promising for deep-UV-active insulating films and lightweight dielectric components.

Triboelectric nanogenerators (TENGs) are limited by poor charge retention and unstable output. This study investigates the effect of graphene oxide (GO) incorporation and environmental humidity on a nylon/polysiloxane-based TENG. Structural and chemical properties were analyzed using XRD, Raman, and FTIR, while SEM and photoluminescence (PL) were used to examine morphology and charge-trapping behavior. Electrical performance was evaluated through dielectric and TENG output measurements. An optimal GO loading of 0.05 wt% yields the highest performance, reaching 58.6 V, 5.7 mu A, and 54.6 mu W (34.1 mW/m(2)). SEM confirms uniform dispersion at this concentration, while PL indicates increased charge-trapping sites. Higher GO content leads to agglomeration and reduced performance. The output strongly depends on humidity, with voltage and current increasing as relative humidity decreases from 70-75% to 60%, due to reduced charge dissipation. The device powers 37 LEDs at higher humidity and similar to 60 LEDs at lower humidity, and demonstrates stable capacitor charging. Unlike complex hybrid systems, this work establishes a direct relationship between GO dispersion, charge trapping, and triboelectric performance. These results demonstrate that controlled GO incorporation and environmental conditions provide an effective strategy for improving TENG performance and enabling practical self-powered systems. This work goes beyond previous studies by explicitly linking GO-induced defect states and interfacial polarization to humidity-dependent charge retention mechanisms.