Tuning the Optical and Electrical Properties of ALD-Grown ZnO Films by Germanium Doping.

In this work, we report on the fabrication of ZnO thin films doped with Ge via the ALD method. With an optimized amount of Ge doping, there was an improvement in the conductivity of the films owing to an increase in the carrier concentration. The optical properties of the films doped with Ge show improved transmittance and reduced reflectance, making them more attractive for opto-electronic applications. The band gap of the films exhibits a blue shift with Ge doping due to the Burstein-Moss effect. The variations in the band gap and the work function of ZnO depend strongly on the carrier density of the films. From the surface studies carried out using XPS, we could confirm that Ge replaces some of the Zn in the wurtzite structure. In the films containing Ge, the concentration of oxygen vacancies is also high, which is somehow related to the poor electrical properties of the films at higher Ge concentrations.

Synergistic Effect of Precursor and Interface Engineering Enables High Efficiencies in FAPbI3 Perovskite Solar Cells.

Formamidinium lead iodide (FAPbI3)-based perovskite solar cells have gained immense popularity over the last few years within the perovskite research community due to their incredible opto-electronic properties and the record power conversion efficiencies (PCEs) achieved by the solar cells. However, FAPbI3 is vulnerable to phase transitions even at room temperature, which cause structural instability and eventual device failure during operation. We performed post-treatment of the FAPbI3 surface with octyl ammonium iodide (OAI) in order to stabilize the active phase and preserve the crystal structure of FAPbI3. The formation of a 2D perovskite at the interface depends on the stoichiometry of the precursor. By optimizing the precursor stoichiometry and the concentration of OAI, we observe a synergistic effect, which results in improved power conversion efficiencies, reaching the best values of 22% on a glass substrate. Using physical and detailed optical analysis, we verify the presence of the 2D layer on the top of the 3D surface of the perovskite film.

Deposition of Thin Electroconductive Layers of Tin (II) Sulfide on the Copper Surface Using the Hydrometallurgical Method: Electrical and Optical Studies.

Thin films of tin (II) sulfide (SnS) were deposited onto a 500 µm thick copper substrate by a chemical bath method. The effect of sodium (Na) doping in these films was studied. The synthesis of the films was performed at temperatures of 60, 70, and 80 °C for 5 min. The microstructure of the SnS films analyzed by scanning electron microscopy (SEM) showed a compact morphology of the films deposited at 80 °C. The edges of the SnS grains were rounded off with the addition of a commercial surfactant. The thickness of different SnS layers deposited on the copper substrate was found to be 230 nm from spectroscopic ellipsometry and cross-section analysis using SEM. The deposition parameters such as temperature, surfactant addition, and sodium doping time did not affect the thickness of the layers. From the X-ray diffraction (XRD) analysis, the size of the SnS crystallites was found to be around 44 nm. Depending on the process conditions, Na doping affects the size of the crystallites in different ways. A study of the conductivity of SnS films provides a specific conductivity value of 0.3 S. The energy dispersive analysis of X-rays (EDAX) equipped with the SEM revealed the Sn:S stoichiometry of the film to be 1:1, which was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis. The determined band-gap of SnS is equal to 1.27 eV and is in good agreement with the literature data.

The Influence of the ITO Layers' Thicknesses on Their Chosen Physical Surface Parameters.

The paper presents the results concerning the influence of the thickness of the ITO and In2O3 layers deposited by the magnetron sputtering method on the physical parameters characterising their surface properties. The characterisation parameters were obtained by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Kelvin probe. The increase in the layers' thickness related to the time of their fabrication causes an increase in the surface roughness and the value of the work function, followed by a decrease in the concentration of elements and compounds in the near-surface area.

Investigation of Ti/Al2O3 + TiO2 and Ti + TiO2/Al2O3 + TiO2 hybrid coatings as protection of ultra-light Mg-(Li)-Al-RE alloys against corrosion.

Low corrosion resistance is a significant problem of magnesium alloys, particularly ultra-light magnesium-lithium alloys. Surface treatment is one way to improve their corrosion resistance. The paper presents the results of tests of Ti/Al2O3 + TiO2 and Ti + TiO2/Al2O3 + TiO2 coatings obtained in a hybrid process combining PVD and ALD methods and ALD coating of Al2O3 + TiO2 type obtained on AE42 (Mg-4Li-2RE) and LAE442 (Mg-4Li-4Al-2RE). Structural studies were performed using scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy and EDS and XPS spectroscopic methods. Potentiodynamic tests and electrochemical impedance spectroscopy EIS in 0.05 M NaCl solution were performed to determine the electrochemical properties of the tested materials. Moreover, tests of surface wettability and tribological properties using the ball-on-disc method were performed. Based on the analysis of anodic polarisation curves and Tafel analysis, it was found that the Ti + TiO2/Al2O3 + TiO2 coating showed the best potentiodynamic properties on both substrates. In particular, on the magnesium-lithium substrate, the value of the polarisation resistance of this hybrid coating is Rpol = 14 × 103 Ω × cm2, and the value of the corrosion current is jcorr = 0.4 µA/cm2. For the uncoated LAE442 substrate, the polarisation resistance is Rpol = 1.05 × 103 Ω × cm2, and the corrosion current value is jcorr = 5.49 µA/cm2. This improvement is due to the synergistic effect of the combined PVD and ALD technologies. The study confirmed the impact of hybrid coatings on improving the anti-corrosion and tribological properties of ultra-light magnesium alloys.

The atomic layer deposition (ALD) synthesis of copper-tin sulfide thin films using low-cost precursors.

In this work we demonstrated the process of co-deposition of copper-tin sulfide species by the atomic layer deposition (ALD) technique using all-low-cost precursors. For the deposition of tin species, the tin(IV) chloride SnCl4was used successfully for the first time in the ALD process. Moreover, we showed that the successful deposition of the tin sulfide component was conditioned by the pre-deposition of CuSxlayer. The co-deposition of copper and tin sulfides components at 150 °C resulted in the in-process formation of the film containing Cu2SnS3, Cu3SnS4andπ-SnS phases. The process involving only tin precursor and H2S did not produce the SnSxspecies. The spectroscopic characteristic of the obtained materials were confronted with the literature survey, allowing us to discuss the methodology of the determination of ternary and quaternary sulfides purity by Raman spectroscopy. Moreover, the material characterisation with respect to the morphology (SEM), phase composition (XRD), surface chemical states (XPS), optical properties (UV-vis-NIR spectroscopy) and electric (Hall measurements) properties were provided. Finally, the obtained material was used for the formation of the p-n junction revealing the rectifyingI-Vcharacteristics.

The Composites of Polyamide 12 and Metal Oxides with High Antimicrobial Activity.

The lack of resistance of plastic objects to various pathogens and their increasing activity in our daily life have made researchers develop polymeric materials with biocidal properties. Hence, this paper describes the thermoplastic composites of Polyamide 12 mixed with 1-5 wt % of the nanoparticles of zinc, copper, and titanium oxides prepared by a twin-screw extrusion process and injection moulding. A satisfactory biocidal activity of polyamide 12 nanocomposites was obtained thanks to homogenously dispersed metal oxides in the polymer matrix and the wettability of the metal oxides by PA12. At 4 wt % of the metal oxides, the contact angles were the lowest and it resulted in obtaining the highest reduction rate of the Escherichia coli (87%), Candida albicans (53%), and Herpes simplex 1 (90%). The interactions of the nanocomposites with the fibroblasts show early apoptosis (11.85-27.79%), late apoptosis (0.81-5.04%), and necrosis (0.18-0.31%), which confirms the lack of toxicity of used metal oxides. Moreover, the used oxides affect slightly the thermal and rheological properties of PA12, which was determined by oscillatory rheology, thermogravimetric analysis, and differential scanning calorimetry.

Investigation of Dye Dopant Influence on Electrooptical and Morphology Properties of Polymeric Acceptor Matrix Dedicated for Ternary Organic Solar Cells.

The publication presents the results of investigations of the influence of dye dopant on the electrooptical and morphology properties of a polymeric donor:acceptor mixture. Ternary thin films (polymer:dye:fullerene) were investigated for potential application as an active layer in organic solar cells. The aim of the research is to determine the effect of selected dye materials (dye D131, dye D149, dye D205, dye D358) on the three-component layer and their potential usefulness as an additional donor in ternary cells, based on P3HT donor and PC71BM acceptor. UV-vis spectroscopy studies were performed, and absorption and luminescence spectra were determined. Ellipsometry parameters for single dye and ternary layers have been measured. The analyses were performed using the Raman spectroscopy method, and the Raman spectra of the mixtures and single components have been determined. Organic layers were prepared and studied using scanning electron microscope and atomic force microscope. For dyes, ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy studies were carried out and the ternary system was presented and analyzed in terms of energy bands.

Damage Development on the Surface of Nickel Coating in the Initial Period of Erosion.

The common occurrence of the phenomenon of cavitation in many industries and the multitude of factors affecting the resistance to cavitation erosion of used materials contribute to the search for methods and appropriate parameters of coating application that are able to minimize the effects of erosion. To determine the validity of the developed application parameters and the method used, cavitation studies and microscopic observations of the development of erosion during the cavitation test were carried out. There was a clear lack of incubation time and a linear increase in losses after 60 min of the test. Moreover, the damage observed during the test overlapped, widening the area of erosion and thus leading to damage to the integrity of the coating.

Effect of Bee Pollen Addition on the Polyphenol Content, Antioxidant Activity, and Quality Parameters of Honey.

Bee pollen is regarded as a valuable source of bioactive substances. Honey enrichment with bee pollen seems to be the most popular way to introduce this bee product into a human diet. The aim of this study was to determine the influence of the addition of bee pollen to honey on the content of selected biologically active pollen components, antioxidant activity, and quality parameters, as well as sensory properties. On the basis of the obtained results, it was established that enriching honey with bee pollen resulted in a significant increase in the level of phenolics, including both flavonoids and phenolic acids, of which kaempferol and gallic acid were present in the highest level. As a result of increasing addition of bee pollen, an increase in the antioxidative, antiradical, and reducing activities of honey was observed. However, the addition of bee pollen to honey resulted in the deterioration of its sensory properties. A decrease in brightness, clarity, and uniformity of color, as well as a decrease in the perception of fragrance, was observed. In the assessment of texture, a decrease in smoothness and spread ability in the mouth was observed, with a significant increase in the feeling of sandiness. In contrast, the evaluation of taste revealed a marked increase in sharpness, acid taste, bitterness, and persistence of the aftertaste, with a simultaneous decrease in sweetness. Honey enrichment with bee pollen resulted in a significant increase in the content of water-insoluble substances, free acidity, specific conductivity, and proline content, with a slight decrease in the content of glucose and fructose.

The Impacts of Crystalline Structure and Different Surface Functional Groups on Drug Release and the Osseointegration Process of Nanostructured TiO2.

In implantable materials, surface topography and chemistry are the most important in the effective osseointegration and interaction with drug molecules. Therefore, structural and surface modifications of nanostructured titanium dioxide (TiO2) layers are reported in the present work. In particular, the modification of annealed TiO2 samples with -OH groups and silane derivatives, confirmed by X-ray photoelectron spectroscopy, is shown. Moreover, the ibuprofen release process was studied regarding the desorption-desorption-diffusion (DDD) kinetic model. The results proved that the most significant impact on the release profile is annealing, and further surface modifications did not change its kinetics. Additionally, the cell adhesion and proliferation were examined based on the MTS test and immunofluorescent staining. The obtained data showed that the proposed changes in the surface chemistry enhance the samples' hydrophilicity. Moreover, improvements in the adhesion and proliferation of the MG-63 cells were observed.

Influence of Conditioning Temperature on Defects in the Double Al2O3/ZnO Layer Deposited by the ALD Method.

In this work, we present the results of defects analysis concerning ZnO and Al2O3 layers deposited by atomic layer deposition (ALD) technique. The analysis was performed by the X-band electron paramagnetic resonance (EPR) spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) methods. The layers were either tested as-deposited or after 30 min heating at 300 °C and 450 °C in Ar atmosphere. TEM and XPS investigations revealed amorphous nature and non-stoichiometry of aluminum oxide even after additional high-temperature treatment. EPR confirmed high number of defect states in Al2O3. For ZnO, we found the as-deposited layer shows ultrafine grains that start to grow when high temperature is applied and that their crystallinity is also improved, resulting in good agreement with XPS results which indicated lower number of defects on the layer surface.

The influence of dielectric permittivity of water on the shape of PtNPs synthesized in high-pressure high-temperature microwave reactor.

In this paper, a novel method for the synthesis of Pt nanoparticles (PtNPs) using a microwave autoclave reactor is proposed. For benchmarking, the obtained results are compared with the traditional, batch method. A novel process window is proposed, which is the application of high-temperature and high-pressure. The main finding is that this only brings advantage, when the ionic strength of the system is enough low. It is explained, that at high pressure and high temperature, water behaves like only a slightly polar solvent, approaching a subcritical state. This reduces the electrostatic stabilization of the particles. Moreover, a change in the Pt particle shape is observed under high pressure and temperature conditions, suggesting that additional physical-chemical processes are involved.

Physicochemical and Biological Characterisation of Diclofenac Oligomeric Poly(3-hydroxyoctanoate) Hybrids as ß-TCP Ceramics Modifiers for Bone Tissue Regeneration.

Nowadays, regenerative medicine faces a major challenge in providing new, functional materials that will meet the characteristics desired to replenish and grow new tissue. Therefore, this study presents new ceramic-polymer composites in which the matrix consists of tricalcium phosphates covered with blends containing a chemically bounded diclofenac with the biocompatible polymer-poly(3-hydroxyoctanoate), P(3HO). Modification of P(3HO) oligomers was confirmed by NMR, IR and XPS. Moreover, obtained oligomers and their blends were subjected to an in-depth characterisation using GPC, TGA, DSC and AFM. Furthermore, we demonstrate that the hydrophobicity and surface free energy values of blends decreased with the amount of diclofenac modified oligomers. Subsequently, the designed composites were used as a substrate for growth of the pre-osteoblast cell line (MC3T3-E1). An in vitro biocompatibility study showed that the composite with the lowest concentration of the proposed drug is within the range assumed to be non-toxic (viability above 70%). Cell proliferation was visualised using the SEM method, whereas the observation of cell penetration into the scaffold was carried out by confocal microscopy. Thus, it can be an ideal new functional bone tissue substitute, allowing not only the regeneration and restoration of the defect but also inhibiting the development of chronic inflammation.

Copper Oxides on a Cu Sheet Substrate Made by Laser Technique.

This paper presents results from the production of copper oxide layers on a Cu sheet substrate using diode and Yb:YAG disc lasers operating in the wavelength ranges of 808-940 nm and 1030 nm. The parameters of these layers were compared with the layer obtained in the thermal process of copper oxidation at 300 °C in an infrared (IR) furnace in a natural atmosphere. Investigations into the layers mentioned above, concerning their topography, chemical composition and roughness, were made using scanning electron microscopy (SEM) and atomic force microscopy (AFM). A hot-point probe was used to determine and check the type of conductivity of the copper oxide layers formed. The optical band gap energy was estimated by applying the Kubelka-Munk method based on spectrophotometric data. Cross-sections and the element distribution maps were made using transmission electron microscopy (TEM). The phase analysis was investigated by the X-ray diffraction method (XRD). In sum, controlled laser oxidations of copper sheets allow for the formation of a mixture of Cu2O and CuO phases. The diode laser allows the production of a layer of copper oxides with a phase composition comparable to the oxides produced by the thermal oxidation method, while the distribution of high phase uniformity in the cross-section of the layer enables the process using a Yb:YAG disc laser.

Nanoporous Anodic Aluminum-Iron Oxide with a Tunable Band Gap Formed on the FeAl3 Intermetallic Phase.

Nanostructured anodic oxide layers on an FeAl3 intermetallic alloy was prepared by two-step anodization in 20 wt.% H2SO4 at 0 °C. The obtained anodic oxide coating was subjected to phase and chemical composition analysis using XPS and XRD techniques. An analysis of the band gap of individual coatings was also performed. The applied parameters of the anodization process were determined, enabling the formation of a nanostructured coating on the FeAl3 intermetallic alloy. Tests were carried out on samples produced at a voltage between 10 V and 22.5 V in 2.5 V steps. The produced coatings were subjected to an annealing process at 900 °C for 2 h in an argon protective atmosphere. Moreover, the influence of the substrate chemical composition on the chemical and phase composition of the anodic oxide are discussed. Band gaps of 2.37 eV at 22.5 V and 2.64 eV at 10 V were obtained directly after the anodizing process. After applying the heat treatment, band gap values of 2.10 eV at 22.5 Vand 2.48 eV for the coating produced at 10 V were obtained.

The Effect of Enriching Honey with Propolis on the Antioxidant Activity, Sensory Characteristics, and Quality Parameters.

Bee products, including propolis, are a valuable source of biologically active substances. The most natural way to introduce propolis in the diet seems to be its addition to honey. The aim of this study was to analyze the effect of honey enrichment with propolis on the content of selected bioactive compounds, antioxidant potential, as well as sensory and qualitative characteristics of honey. On the basis of the obtained results, it was stated that the addition of propolis extract to honey contributed to a significant increase in the content of polyphenolic compounds, including flavonoids and phenolic acids, among which chrysin, pinocembrin, p-coumaric, and ferulic acid reached the highest level. The increase of antioxidant, antiradical, and reduction in activity of enriched honey was observed as a result of increasing addition of propolis extract. However, the enrichment of honey with propolis contributed to deterioration of the sensory properties. The changes in color, smell, texture, and taste were observed. The addition of propolis to honey had no significant effect on 5-hydroxymethylfurfural (HMF) and sugar content, and specific conductivity. On the other hand, a significant increase in free acidity and content of substances insoluble in water was observed. The obtained results indicate that honey supplemented with propolis extract can be an excellent source of antioxidant compounds, nevertheless, the amount of additive used is strongly dependent on changes in sensory characteristics and consumer acceptability.

Incorporation of Ca ions into anodic oxide coatings on the Ti-13Nb-13Zr alloy by plasma electrolytic oxidation.

The present work concerns the surface modification of The Ti-13Nb-13Zr alloy by electropolishing and plasma electrolytic oxidation (PEO) process in Ca-containing electrolytes: calcium formate and calcium lactate solutions (0.1-1.0 mol dm-3) under voltages of 200 and 400 V. As a result of the PEO process, a porous oxide layer containing incorporated calcium compounds was formed on the Ti-13Nb-13Zr alloy surface. The morphology and chemical composition of the modified Ti-13Nb-13Zr alloy were investigated using scanning electron microscopy (SEM + EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). An increase in the applied voltage caused an increase in the number of pores and an increase in the amount of calcium incorporated in the oxide layer. Analysis showed that all samples were covered by titanium oxide, which was present in the form of anatase and/or rutile. In course of the experiments, it was showed that the proposed procedure has a positive effect on the overall bioactivity of the Ti-13Nb-13Zr alloy. Bioactivity investigations using simulated body fluid (SBF) confirmed the formation of apatite on the anodized surfaces. The cell adhesion results obtained by the use of human bone marrow mesenchymal stem cells (hBMSC) demonstrated that the PEO coatings on the Ti-13Nb-13Zr alloy remarkably enhanced the cytocompatibility of the substrate, indicating a potential application in orthopedic surgeries. The incorporation of Ca into the oxide layer proceeded to a higher extent when the PEO treatment was performed in the calcium lactate bath. The oxide layers formed in the calcium lactate solution exhibited also superior biological behavior towards hBMSC. This can be ascribed to the presence of carboxylic groups onto coatings' surface (as identified by XPS), which facilitated the anchoring of cells and tissues.

Sorption of Molybdates and Tungstates on Functionalized Montmorillonites: Structural and Textural Features.

Montmorillonite-the most popular mineral of the smectite group-has been recognized as a low-cost, easily available mineral sorbent of heavy metals and other organic and inorganic compounds that pollute water. The aim of this work was to determine the sorption mechanism and to identify the reaction products formed on the surface of montmorillonite and organo-montmorillonite after sorption of molybdates (Mo(VI)) and tungstates (W(VI)). Montmorillonites are often modified to generate a negative charge on the surface. The main objective of the study was to investigate and compare the features of Na-montmorillonite (Na-M), montmorillonite modified with dodecyl trimethyl ammonium bromide (DDTMA-M), and montmorillonite modified with didodecyl dimethyl ammonium bromide (DDDDMA-M) before and after sorption experiments. The material obtained after sorption was studied by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The XRD pattern showed the presence of a new crystallic phase in the sample that was observed under an SEM as an accumulation of crystals. The FTIR spectra showed bands related to Mo-O and W-O vibration (840 and 940 cm-1, respectively). The obtained results suggest that molybdenum(VI) and tungsten(VI) ions sorb onto the organo-montmorillonite in the form of alkylammonium molybdates and tungstates.

Application of metallic inks based on nickel-silver core-shell nanoparticles for fabrication of conductive films.

Conductive inks based on nickel nanoparticles (NPs) have attracted much attention as a low-cost replacement for the currently used silver and gold inks, for fabrication of printed electronic circuits and devices. Nickel NPs as a component of conductive inks should be stable against oxidation process at all stages of preparation of conductive patterns: ink formulation and storage, printing, and post-printing treatment. In the present study, the oxidation resistance of the Ag layer and the conductive properties of the Ni core allowed the use of nickel-silver core-shell (Ni@Ag) NPs as the component of conductive ink. Thick films composed of Ni-Ag core-shell NPs were deposited on a glass substrate and then sintered at temperatures ranging from 250 °C-370 °C. The conductivity of Ni@Ag coatings after sintering at 350 °C reached 11% of that for a bulk nickel.