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Nickel thin films were deposited to the different thicknesses onto glass substrates using electron-beam glancing angle deposition. The changes in the structural, chemical, and magnetic properties of the films have been investigated. The obtained morphological and microstructural results revealed that the deposited samples consisted of vertical columns with a thickness in the range of 50 nm to 140 nm and a diameter of 15 nm to 29 nm. With the increase in film thickness, the surface roughness increases as well. Chemical analysis showed that the main phase in the samples is metallic Ni, with a certain amount of NiO. In addition, magnetic measurements exhibit that all Ni films show typical hysteresis loops with a uniaxial magnetic anisotropy. The coercivity was found to increase with the thickness up to 110 nm followed by its further decrease, probably due to the differences in the structure of the columns themselves as well as the combined contributions of two different antiferromagnetic (NiO) and ferromagnetic (Ni) phases created in the deposited nanostructures.

The paper presents a study on the structural and optical properties of nickel (Ni) thin films in the shape of vertical columns obtained by using the glancing angle deposition method. The films are deposited onto glass substrates at a fixed deposition angle of 85° to the different thicknesses of 50 nm, 80 nm, 110 nm, and 140 nm. Field emission scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and high resolution transmission electron microscopy (HR-TEM) were utilized to analyze the morphological, chemical, and microstructural properties of the films. SEM and TEM analyses are showing well-defined columnar structures, where the increase in thickness leads to more porous films and larger column diameters. The results of the surface examination of the XPS confirm that metallic Ni is a major phase in the deposited structures, but all samples also exhibit a certain amount of oxide phases. The optical measurements of the effective dielectric function reveal that both real and imaginary parts are strongly influenced by the changes in the film thickness. The surface plasmon resonance (SPR) peak is significantly shifted from 585.6 nm, as obtained for a 50 nm thick film, to 1291.8 nm in the case of a thickness of 140 nm. The variation in SPR peak position can be related to the differences in the film's morphology, and it is attributed to the changes in the size of the formed Ni nanoparticles. Finally, the experimental results show that with increasing film thickness, the electrical resistivity decreases. Both optical and electrical properties are found to be determined by the growth mechanism, and they are discussed on the basis of the defect concentration of the films.

The following investigation presents the thermal treatment of geopolymer based on metakaolin, with the addition of 1% and 5% of neodymium in the form Nd2O3, at 300˚C, 600˚C and 900˚C. Six samples were synthesized in total. Samples GT1 and GT2 containing 1% and 5% of Nd2O3, and they were treated at 300˚C, while the samples GT3 and GT4 also had the same percentage composition of Nd2O3 and were treated at 600˚C, and the samples GT5 and GT6 were treated at 900˚C with the same percentage of Nd2O3. Physical and chemical changes in the aluminosilicate geopolymer matrix were monitored. The incorporation of rare earths into the polymer network of aluminosilicates has been proven to disrupt the basic structure of geopolymers, however, with increased temperature, these materials show even more unusual properties. DRIFT was employed to investigate the structural properties of thermally treated geopolymers. Additionally, TEM provided further insight into the structural changes induced by thermal treatment and Nd2O3 doping. SEM was used to observe the effect of thermal treatment temperature (300˚C and 600˚C) on geopolymer porosity, which resulted in the appearance of large pores and cracks in the material. The UV/Vis spectra of the synthesized Nd3+ doped geopolymers exhibited attractive optical properties. The photoexcitation of electrons from the valence band to the conduction band in the geopolymer structure is responsible for the absorbance observed at 260 nm, while the minor peaks at slightly longer wavelengths can be linked to Nd3+

To enhance the utilization efficiency of platinum (Pt) in electrochemical energy conversion, the precise selection of support materials presents a highly promising strategy. We have developed an efficient and stable bifunctional catalyst for methanol oxidation (MOR) and hydrogen evolution (HER) reaction in an alkaline medium. The Pt-based electrocatalyst, denoted as Pt/e-rGO with low Pt loading was successfully synthesized using graphene sheets as the support via chemical reduction using formic acid as the reducing agent. Graphene sheets are obtained by anodic electrochemical exfoliation of graphite tape. Significant enhancement of intrinsic activity toward MOR and HER was achieved for Pt/e-rGO compared to the commercial Pt/C catalyst. Structural characterization was performed by TEM, SEM and XPS. XPS analysis shows that the graphene is highly reduced. TEM analysis unveiled that the majority of the Pt nanoparticles (NPs) exhibit a diameter in the range of 4-5 nanometers, which is significant because the efficiency of electrooxidation of methanol on supported Pt NPs shows a strong dependence on particle size distribution. Catalyst activity was studied by cyclic voltammetry and linear sweep voltammetry in 0.1M KOH. Electrochemical active surface area (ECSA) was measured by CO-stripping voltammetry and estimated to be 67.93 m2 /g. Current density of 11.28 mA/cm2 ECSA at 0.82 V vs. RHE for MOR is achieved. Onset potential for MOR is 0.55 V vs. RHE. Meanwhile, for HER overporential at the current density -10 mA/cm2 ECSA was 119 mV.

This study focused on analyzing samples of aluminosilicate materials in which different percentages of samarium (III)-oxide were incorporated. Basic samples and thermally treated samples at 600 °C were analyzed. Introducing samarium (III)-oxide into the polymer matrix of aluminosilicates has been demonstrated to alter the fundamental structure of aluminosilicate materials. Interestingly, at elevated temperatures, these materials exhibit even more distinctive properties. The gamma ray spectrometric analysis results were used to conduct radiological analysis. Different methods monitor physico-chemical changes within the aluminosilicate materials. By introducing Sm3+ into the aluminosilicate matrix, the basic structure of the aluminosilicate is disturbed. The DRIFT method was used to analyze the structural properties. The analysis of the microstructural properties of the selected samples was carried out using a scanning electron microscope (SEM) and enabled the examination of the fine details of the structure of the materials thermally treated at 600 °C which resulted in the appearance of significant pores and cracks in the material.

Background: The use of nitinol (NiTi) archwires in orthodontic treatment has increased significantly due to unique mechanical properties. The greatest obstacle for safe orthodontic treatment is chemically or microbiologically induced corrosion, resulting in nickel (Ni) release. The aim of this investigation was to enhance corrosion resistance and introduce antibacterial properties to NiTi archwires by coating them with copper (Cu) doper titanium nitride (TiN-Cu). Methods: NiTi archwires were coated with TiN-Cu using cathodic arc evaporation (CAE) and direct current magnetron sputtering (DC-MS). The morphology of the sample was analyzed via field emission scanning electron microscopy (FESEM) and chemical composition was assessed using energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy (FTIR). Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to estimate the ion release. The biocompatibility of samples was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl tetrazolium bromide (MTT) assay. Antibacterial activity was tested against Streptococcus mutans and Streptococcus mitis. Results: Physicochemical characterization revealed well-designed coatings with the presence of TiN phase with incorporated Cu. TiN-Cu-nanocoated archwires showed a statistically lower Ni release (p < 0.05). Relative cell viability was the highest in 28-day eluates of TiN-Cu-nanocoated archwires (p < 0.05). The most remarkable decrease in Streptococcus mitis concentrations was observed in the case of TiN-Cu-coated archwires (p < 0.05). Conclusion: Taking into account biocompatibility and antibacterial tests, TiN-Cu-nanocoated archwires may be considered as a good candidate for further clinical investigations

Amorphous, non-doped, and copper- and selenium-doped Sb2S3 nanoparticles were synthesized by a hot-injection method. Zinc-doped Sb2S3 nanoparticles were prepared for the first time using the same approach. Electron microscopy revealed that spherical nanoparticles of 1–4 nanometers aggregated into larger spherical clusters. Introducing dopants into the Sb2S3 structure neither influenced the samples’ spherical morphology nor their sizes. The presence of the dopants (Cu, Se, or Zn) was confirmed by energy dispersive X-ray (EDX) and, in the case of Zn, also by inductively coupled plasma-mass spectrometry (ICP-MS). The X-ray powder diffraction (XRPD) patterns of the non-doped and doped samples imply an amorphous structure. Crystalline Zn-doped Sb2S3 revealed defined peaks from only the Sb2S3 phase, indicating successful doping. Diffuse reflectance spectroscopy (DRS) revealed high optical bandgap energies (2.03–2.12 eV) compared to the values (1.6–1.7 eV) for large non-doped and doped particles obtained at 240 °C, which might be attributed to a quantum size effect. X-ray photoelectron spectroscopy (XPS) revealed a phase without any impurities for the undoped and characteristic peaks for copper, selenium, and zinc Auger for the doped samples. XPS valence band confirm for the Zn-doped particles a shift towards lower binding energy compared to the non-doped samples, indicating successful doping. Photoluminescence (PL) measurements show that embedding Zn into the Sb2S3 host lattice suppresses the wide luminescence band related to intrinsic vacancy defects. Narrow peaks at 1.7–2.4 eV were found to be associated with singlet excitons. The energy dependence of the light emission on the synthesized nanoparticles’ size suggests quantum confinement. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.

Enhanced optical properties of TiO2 thin films can be achieved by doping or coating with metals. Metal-doped TiO2 can reduce electron-hole recombination and increase hydroxyl radical concentration on the surface of TiO2, resulting in increase of the photocatalytic activity. TiO2 and TiO2-Au thin films were obtained by DC magnetron sputtering of Ti target with Ar ions in O2 atmosphere. In the case of Au buffered TiO2 thin films, two different systems were deposited for comparison. Post deposition annealing at 400 °C was carried out in nitrogen atmosphere for 3 h. The structural and optical characteristics of the prepared films were investigated in detail by the combination of high-resolution microscopic and spectroscopic techniques. The photo-degradation rate was measured using Rhodamine B which simulated pollutant. Post deposition annealing resulted in diffusion of Au atoms through the layer as it was revealed by transmission electron microscopy and energy dispersive X-ray spectroscopy. The obtained TiO2 thin films were found to be amorphous after deposition and annealing at 400 °C leads to crystallization of anatase phase. Analysis of the binding energy in the corresponding X-ray photoelectron spectra has confirmed stoichiometry of TiO2 and that concentration of Au on the surface can be controlled by sputtering and annealing conditions, thus changing optical properties by influencing the surface plasmonic nature. All Au doped TiO2 thin films exhibited enhanced wettability and photo-degradation rates when compared to pristine titania films. © 2022 Elsevier B.V.

In this study, we have investigated the effect of thickness on the structural and optical properties of copper (Cu) helical nanostructures. Thin films with thicknesses of 160 nm, 280 nm, 450 nm, and 780 nm were obtained by e-beam glancing angle deposition. The morphology and the microstructure were studied by field emission scanning electron microscopy, x-ray diffraction and transmission electron microscopy, while for the optical analysis measurements spectroscopic ellipsometry was used. The results show that the deposited structures are porous with nanometer-sized crystallites preferentially oriented along (111) planes, as well as that the diameter of the helices increases with thickness. Detailed analyses of optical properties have demonstrated that the dielectric function of Cu structures is greatly influenced by the films thicknesses. With increasing thickness from 160 nm to 780 nm, the surface plasmon resonance peak was shifted from 1.31 eV to 1.05 eV, which was correlated with the growth mechanism and the size of deposited nanostructures.

Rare earth oxides have been broadly utilised in different research areas due to their unique properties. This research aims to examine the effect of Nd and Sm in the form of oxide addition in the metakaolin-based geopolymer matrix. Metakaolin-based geopolymers with the addition of different percentages of Sm2O3 and Nd2O3 (S1-S6) were synthesised. Samples contained 0.1% Sm; 1% Sm; 5% Sm, and 0.1% Nd, 1% Nd, and 5% Nd. The focus was on monitoring the polymerisation process using the DRIFT method for 7, 14, 21 and 28 days. The phase composition of the samples was confirmed by the XRD method, while the morphology of the samples was analysed by SEM analysis. After 28 days, due to the polymerisation process, the binding of Neodymium and Samarium ions were incorporated into the structure.

In this work, the influence of different deposition angles on the structural, chemical and magnetic properties of nickel (Ni) thin films was investigated. Nickel samples were deposited by glancing angle deposition technique at two different angles, 65o and 85o. Characterization of the thin films was carried out by scanning electron microscopy, X-ray photoelectron spectroscopy and magneto-optical Kerr effect microscopy. Structural analysis was found that the changes in the deposition angle have a great influence on the porosity of the film as well as on the amount of the present nickel oxide (NiO) in the samples. On the other hand, we have also found that different deposition angle changes the magnetic response of nickel film. The coercivity of the samples deposited at the angle of 85o is significantly higher compared to the samples deposited at lower angle which could be correlated with the higher porosity and the amount of NiO in the thin films.

Phosphate tungsten bronze (WPB) and phosphate molybdenum bronze (MoPB) were synthesized and modified with rhenium. The existing phases were established by X-ray powder diffraction (XRPD), electron paramagnetic spectroscopy (EPR) and Field emission scanning electron microscopy (FESEM). The electroactivity of bronze samples, with and without rhenium for hydrogen evolution reaction (HER) was tested. The influence of carbon black presence in the catalytic ink on the electrochemical activity was investigated. Collected results provide insight into the effects of the constituents of an electrode on its electrochemical activity.

In this study, nickel (Ni) thin films were deposited at two different angles (65o and 85o) using Glancing Angle Deposition technique, to the thicknesses of 60 – 290 nm. Structural analysis of the deposited films was performed by scanning electron microscopy and X-ray diffraction, while spectroscopic ellipsometry was used for the investigation of optical properties. Electrical resitivity of the samples was determined by four-point probe method. Structural analysis showed that the Ni films grow in a shape of zigzag nanocolumns, where the deposition angle strongly affects their porosity. As the thickness of the films increase they absorb light strongly and become less dense. Besides, samples deposited at the angle of 85o exhibit higher values of electrical resistivity as compared to the samples deposited at the angle of 65o, which can be correlated with high porosity and the growth mechanism of the deposited nanostructures.

In this work we deposited nickel thin films by Glancing Angle Deposition at two different angles (65 degrees and 85 degrees) onto glass substrates. The structure of the films, thicknesses between 50 and 200 nm, was studied by scanning electron microscopy, atomic force microscopy and X-ray diffraction, while the chemical properties were analyzed using X-ray photoelectron spectroscopy. According to the obtained results it can be seen that the deposition angle has influence on porosity, crystallinity and surface roughness. Optical properties were investigated by spectroscopic ellipsometry and electrical properties were measured by four point probe. Spectroscopic ellipsometry revealed that the refractive index and extinction coefficient varied with thickness and deposition angle, which can be correlated with changes in microstructure and porosity of Ni films. The observed variations in resistivity could be attributed to the changes in the width of the columns, as well as to the amount of oxide present in the samples.

The interaction of ultrashort laser beam with metal surfaces may induce the generation of periodic structures (LIPSS) with period less than the incoming wavelength, opening wide area of application [1, 2]. The presence of the underneath layer influences the quality of the LIPSS [3] . We have exposed multilayer thin films Ni/Ti, Ni/Pd, W/Ti, Ti/Ta to femtosecond beams of various wavelengths and powers. The interactions have been performed by Mira900 fs laser of Coherent. Detailed surface morphology after irradiation was examined firstly by optical microscopy, and then by scanning electron microscopy (JEOL JSM-7500F, Tokyo, Japan). Two types of structures have been noticed. Their appearance differ in the direction against the polarization direction, in pronounced ablation and in the spatial period, enabling their grouping into LIPSS of higher and lower spatial frequencies. Surface plasmon polariton is seen as the most probable cause of periodic distribution of energy at the surface and consequently to LIPSS.

Yellow gentian (Gentiana lutea L.), a medicinal plant widely used in traditional medicine, displays multiple biological effects, ranging from beneficial to toxic. Since many promising applications have been reported so far, our aim was to evaluate its potential concentration- and time- dependent cytotoxic and genotoxic effects in vitro . To that end we exposed human peripheral blood mononuclear cells to 0.5, 1, and 2 mg/mL of yellow gentian root extract (YGRE) to determine its effects on oxidative stress parameters [pro/antioxidant balance (PAB) and lipid peroxidation], DNA damage (alkaline comet assay and chromosome aberrations), and cell viability (trypan blue exclusion test). Cell viability decreased with increasing concentrations and treatment duration. Only the lowest YGRE concentration (0.5 mg/mL) increased oxidative stress but produced minor DNA damage and cytotoxicity. At higher concentrations, redox parameters returned to near control values. The percentage of chromosome aberrations and percentage of DNA in the comet tail increased with increased YGRE concentration after 48 h and declined after 72 h of treatment. This points to the activation of DNA repair mechanism (homologous recombination), evidenced by the formation of chromosomal radial figures after 72 h of treatment with the highest YGRE concentration of 2 mg/mL. Our results suggest that YGRE, despite induction of cytotoxic and genotoxic effects, activates cell repair mechanisms that counter oxidative and DNA lesions and induce cell death in highly damaged cells. Therefore, observed protective effects of yellow gentian after longer exposure could be a result of activated repair and removal of cells with irreparable damage.

Fe/Polyethylene nanocomposite was synthesized by ion beam implantation of 56Fe+ into bulk high-density polyethylene. Nanoscale surface morphology along with magnetic and optical behavior was investigated. The aim of the research was to investigate changes of polyethylene's surface layer morphology with the change of Fe implantation fluence in the high fluence range and to find correlations with the magnetic and optical behavior. Four implantation fluences were applied: 5 × 1016, 1 × 1017, 2 × 1017 and 5 × 1017 cm−2, while the implantation energy was 95 keV. Concentration profiles of implanted Fe were analyzed by Rutherford backscattering spectrometry, showing Fe concentration profile maxima closer to the surface with increasing implantation fluence. Cross-sectional transmission electron microscopy showed the formation of metallic nanoparticles with sizes in a range from below 1 nm up to few tens of nanometers, depending on the fluence, and for the highest implantation fluence, a continuous layer was formed. Magneto-optic Kerr effect magnetometry demonstrates weak ferromagnetic behavior for the 2 higher fluences, and superparamagnetic for the 2 lower fluences. The UV-VIS remission function spectra show the peak in the UV region, which we attribute to iron nanoparticles.