Sulfide Films Research Articles

Predictive Thermal Modeling and Characterization of Ultrasonic Consolidation Process for Thermoplastic Composites

Abstract Ultrasonic consolidation (USC) of thermoplastic composites is a highly attractive and promising method to manufacture high-performance composites. This work focuses on USC of dry carbon fiber (CF) fabrics with high-temperature polyphenylene sulfide (PPS) films. Experimental trials to assess feasibility of the process are time-consuming. Consequently, a predictive thermal model would facilitate process parameters selection to reduce expensive trial-and-error approaches. This paper presents a 2D finite element model of samples under consolidation, incorporating equations for viscoelastic heating, matrix phase change, and material properties. Theoretical temperature profiles for nodes of interest were compared to the corresponding experimental temperature curves for various control parameters (i.e., weld time and vertical displacement of sonotrode) and showed good agreement during heating phase. It was found that welding time values below 1750 ms were insufficient to reach melting temperature, whereas weld times above 3000 ms led to the lowest average void content (2.43 ± 0.81%). More specifically, the time the material spent above melting temperature, i.e., residence time, was established as a parameter that could estimate cases resulting in better consolidation and lower void content (time above 2600 ms for void content below 2.5%). X-ray diffraction (XRD) characterization revealed that the USC process led to mostly amorphous PPS, due to the high cooling rates (70 °C/s to 108 °C/s). Overall, the thermal model and micro-structural outcomes confirmed the feasibility of the USC process for layered composites made from dry fabric and high-temperature thermoplastic films.

Analysis of the influence of aggressive factors and conditions on the composition of corrosive products

Data on the use of the X-ray diffraction method in the analysis of the composition of corrosion products are presented. Such knowledge makes it possible to obtain information on the mechanisms of corrosion development and the protective properties of corrosion products, being either dense (with certain protective properties against corrosion) or loose (with a low level of protection against corrosion), which doesn't prevent the penetration of corrosive media to steel surfaces. Under H2S conditions, a layer of mackinawite (tetragonal FeS) is formed on the surface of steels, and in acidic environments of formation water imitations, it was found that, in addition to it, cubic FeS is formed. Iron sulfide with a cubic crystal structure, being metastable, reduces the protective properties of the sulfide film in aggressive acidic H2S media. During carbon dioxide corrosion of steel, the main product is siderite (FeCO3), characterized by the phenomenon of isomorphism (i.e. changes in the chemical composition of the phase while maintaining its crystal structure). It is established that in the formation water model, sediments of non-stoichiometric composition CaxFeyCO3 and (XFe)CO3 are formed, where X = (Са2+, Mg2+, Mn2+). Both of them are poorly crystallized and have defects in the crystal structure, which reduce their protective properties relative to the stoichiometric FeCO3 formed in a 3%NaCl solution. A corrosion inhibitor in aqueous media promotes the adsorption of the inhibitor film, preventing the formation of corrosion products.

Chemical Synthesis, Morphology, and Optical Properties of Manganese-Doped Zinc Sulfide Films

Chemical Synthesis, Morphology, and Optical Properties of Manganese-Doped Zinc Sulfide Films

Effect of Polyphenylene Sulphide Particles and Films on the Properties of Polyphenylene Sulphide Composites.

Glass fibre-reinforced polyphenylene sulphide composites were prepared by hot-pressing glass fibre fabrics and polyphenylene sulphide resins. The effects of different polyphenylene sulphide resin forms on the properties of the composites were investigated using scanning electron microscopy, dynamic mechanical analyser, pendulum impact tester and universal testing machine. The results showed that different polyphenylene sulphide resin forms had nearly no effect on the glass transition temperature of the composites, which are all located at about 100 °C. Compared with other polyphenylene sulphide composites, the bending strength of polyphenylene sulphide film composites was the highest, reaching 314.58 MPa, and the impact strength of polyphenylene sulphide particle composites was the highest, reaching 245.4 KJ/m2. The bending strength and impact strength were calculated using a standard fraction, and the highest standard fraction was obtained when the ratio of polyphenylene sulphide film to particle was 1:2. The impact strength and bending strength could be obtained. The impact strength reached 229.8 KJ/m2, and the bending strength reached 284.16 MPa.

Tin Sulfide (SnS) Films Deposited by an Electric Field-Assisted Continuous Spray Pyrolysis Technique with Application as Counter Electrodes in Dye-Sensitized Solar Cells.

The deposition of tin sulfide (SnS) nanostructured films using a continuous spray pyrolysis technique is reported with an electric field present at the nozzle for influencing the atomization and the subsequent film deposition. In the absence of the electric field, the X-ray diffraction pattern shows the orthorhombic phase of SnS with a crystallographic preferred orientation along the (040) plane. The application of the electric field results in significant improvement in the morphology and a reduction in surface roughness (28 nm from 37 nm). The direct optical band gap of the films deposited with and without the electric field is estimated to be 1.5 and 1.7 eV, respectively. The photothermal deflection spectroscopy studies show a lower energetic disorder (no Urbach tail), which indicates an annealing effect in the SnS films deposited under the electric field. The improvement in the film properties is reflected in the expected improvement in the power conversion efficiency (PCE) of dye-sensitized solar cells fabricated using the SnS film as a counter electrode. An enhancement of PCE from 2.07% for the film deposited without the electric field to 2.89% for the film deposited with the electric field shows the role of the electric field in the fabrication of improved SnS films.

Growth mechanism of nano-plates structured SnS films on different substrates in glancing angle deposition method

In this work, Tin (II) sulfide films have been deposited on glass, Indium Tin Oxide, and Fluorinated Tin Oxide substrates at the deposition angles of 0º, 65º, and 85º using Physical Vapor Deposition method equipped with Glancing Angle Deposition technique. Based on the results obtained from the X-ray diffraction technique, the crystalline structure of substrates and the angle of depositions along with their effects on the structure of SnS nano-plates have been investigated. Using Raman analysis, the phonons lifetime of the samples was found to change with the type of substrate and the employed deposition angle. Based Energy-dispersive X-ray spectroscopy analysis, the atomic ratio of Sn to S was observed to change with the change of deposition angle, substrate type and variation the diameter of nano-plates. This phenomenon resulted the formation of the second phase of Sn2S3 which was confirmed by Raman and X-ray diffraction patterns. The nano-sheets-like growth of all the samples has been confirmed using Felid Emission Scanning Electron Microscopy analysis. For further morphological studies, the Atomic Force Microscopy analysis has been applied, by which the direct relation between the substrate roughness and the final structure of the samples has been observed. The relation between the substrate roughness and the deposition angle in the growth process of SnS nano-sheets has been explained.

Space-charge-limited current passivation of the self-powered and ultraviolet-to-visible range bilayer p-Si/n-Bi2S3 heterojunction photodetector by Ag coating

In this research, effect of the Ag coating on the physical properties of the mesostructured bismuth sulfide (Bi2S3) films for optoelectronic applications was studied. Bi2S3 films were deposited using the chemical vapor deposition (CVD) method in an atmosphere-controlled tube furnace. X-ray diffraction (XRD) results showed the formation of polycrystalline orthorhombic Bi2S3 films. Scanning electron microscopy (SEM) images indicated that the Ag coating decreased the morphology size on the surface of the Bi2S3 film. The optical energy band gap of the Bi2S3 film was reduced when Ag coating was used (from 1.67 to 1.62 eV). Electrical results indicated that the Ag coating increased the carrier concentration (from 1.89 ×10+18 to 35.30 ×10+18 cm−3) and flat band potential (from 0.02 to 0.65 V). Moreover, the charge transport mechanism study of Bi2S3-based devices with Ag/p-Si/n-free or Ag-coated Bi2S3/Ag configuration indicated the existence of the space-charge-limited current behavior in the free-coated device, which used the Ag coating to passivate it due to the changes in the electronic band structure. The Bi2S3 films were characterized as a photodetector; it was observed that adding the Ag coating enhanced the quality parameters (QPs). Furthermore, the response of the Bi2S3-based photodetectors increased when longer wavelengths were applied. Therefore, more studies on improving the responsivity demonstrated the mesostructured Bi2S3 films can be a potential candidate to be used as self-powered and ultraviolet-to-visible range photodetectors.

Electrodeposited amorphous nickel–iron phosphide and sulfide derived films for electrocatalytic oxygen evolution

The preparation of inexpensive and efficient electrocatalysts for oxygen evolution reaction (OER) is crucial in the widespread application of water electrolyzers. A simple one-step aqueous electrodeposition method is utilized to prepare amorphous nickel-iron sulfide (Ni–Fe–S) and phosphide (Ni–Fe–P) films on Ni foam. The deposited films are highly porous, and can convert to active electrocatalysts for OER. In 1 M KOH, the Ni–Fe–S shows the highest OER activity, and requires only 230 mV overpotential to reach 0.05 A cm−2 OER current densities. The Fe–Ni–S also sustains the 30 h 0.05 A cm−2 galvanostatic OER test. Ex-situ characterizations show that sulfur in the Fe–Ni–S is oxidized and leached into the solution during OER, and that (oxy)hydroxide layer is formed at the surface. The adsorption energy of the hydroxyl group, an OER intermediate, is tuned by the electron interaction between the Ni and Fe, and the Ni–Fe–S exhibits the optimum hydroxyl group adsorption energy and the most facile OER kinetics. Also, higher intrinsic OER activity is observed for the electrodeposited amorphous nickel phosphide-derived film than the amorphous nickel sulfide-derived film.

Plasmon-enhanced upconversion luminescence with the hybrid structure of semiconductor-insulator-semiconductor

High-quality hexagonal NaYF4:Er/Yb particles and monodisperse copper(I) sulfide nanoparticles (NPs) were obtained with the solvothermal method and the hot-injection method, respectively. The hybrid structure of semiconductor-insulator-semiconductor (SIS) was constructed for upconversion luminescence (UCL). The results showed that compared with that of NaYF4:Er/Yb-SiO2 particles, the luminous intensity of SIS was promoted by 12.5 folds, and the quantum yield of SIS can reach to 0.89%. Furthermore, the optical field distribution in the vicinity of hybrid structure of SIS was numerically simulated based on the finite-time domain-difference method (FDTD). The UCL enhancement of the SIS originates from the amplified optical field, which was attributed to the localized surface plasmon resonance (LSPR) effect of copper(I) sulfide NPs and the local effect of the copper(I) sulfide film on the excited light.

PbS and PbO Thin Films via E-Beam Evaporation: Morphology, Structure, and Electrical Properties.

Thin films of lead sulfide (PbS) are being extensively used for the fabrication of optoelectronic devices for commercial and military applications. In the present work, PbS films were fabricated onto a soda lime glass substrate by using an electron beam (e-beam) evaporation technique at a substrate temperature of 300 °C. Samples were annealed in an open atmosphere at a temperature range of 200–450 °C for 2 h. The deposited films were characterized for structural, optical, and electrical properties. Structural properties of PbS have been studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and Rutherford backscattering spectrometry (RBS). The results of XRD showed that the PbS thin film was crystalline in nature at room temperature with cubic crystal structure (galena) and preferential (111) and orientation (022). The morphology of the thin films was studied by FESEM, which also showed uniform and continuous deposition without any peel-off and patches. EDS analysis was performed to confirm the presence of lead and sulfur in as-deposited and annealed films. The thickness of the PbS film was found to be 172 nm, which is slightly greater than the intended thickness of 150 nm, determined by RBS. Ultraviolet-Visible-Near-Infrared (UV-Vis-NIR) spectroscopy revealed the maximum transmittance of ~25% for as-deposited films, with an increase of 74% in annealed films. The band gap of PbS was found in the range of 2.12–2.78 eV for as-deposited and annealed films. Hall measurement confirmed the carriers are p-type in nature. Carrier concentration, mobility of the carriers, conductivity, and sheet resistance are directly determined by Hall-effect measurement. The as-deposited sample showed a conductivity of 5.45 × 10−4 S/m, which gradually reduced to 1.21 × 10−5 S/m due to the composite nature of films (lead sulfide along with lead oxide). Furthermore, the present work also reflects the control of properties by controlling the amount of PbO present in the PbS films which are suitable for various applications (such as IR sensors).

ДОСЛІДЖЕНЯ ПРОЦЕСІВ НАВОДНЮВАННЯ ВУГЛЕЦЕВИХ СТАЛЕЙ РІЗНОЇ СТРУКТУРИ У СІРКОВОДНЕВИХ СЕРЕДОВИЩАХ

The effect of applied static loads, structure, and carbon content in steels on their hydrogenation was investigated in the paper. The content of absorbed hydrogen was determined by the method of vacuum extraction at temperatures of 200, 400, 600 and 800 °С for 720 hours, after corrosion in the NACE solution. It was shown that the hydrogenation of 0.8% C steel in the number of structures: pearlite, sorbite, troostite and martensite increased. The ferrite-pearlite structure of 0.45% C steel was the most intensively hydrogenation (19.4 ppm), sorbitic, troostitic and martensitic - less by 30...50%. The main contribution to the absorbed hydrogen was made by diffusive-mobile hydrogen. Its share in the total amount of absorbed reached~65...74% for pearlitic, 50...54% sorbitic, 64...78% troostitic and ~67% martensitic U8 steel structure. For steel 45, it is ~61...72% for ferrite-pearlitic, ~74...79% sorbitic, ~61...75% troostitic, and ~52...85% martensitic. The absorbed hydrogen content of 0.8 % C steel with sorbitic, trostitic, and martensitic structures at temperatures of 400, 600, and 800 ºС increased, while that of steel 45, on the contrary, decreased. This indicated the greater strength of the hydrogen-metal bond in 0.8 % C steel. Therefore, the structure of steels affects the sorption of hydrogen more than the carbon content. Applied static loads  = 300 MPa increased the content of hydrogen absorbed by steels by ~9...15%. On 0.8% C steel, this manifests itself more significantly - СН/С0Н= 1.3...1.8. As the imbalance of the structure increased, the resistance of steels to corrosion cracking under static loads decreased. This was determined by the dispersity of the structure and the morphology of sulfide films, which are formed during the corrosion of steels in the NACE solution. Therefore, static loads most contributed to the hydrogenation of 0.8 % C steel with a troostite structure, and 0.45% C - troostite and martensitе.

Selective thermal emission and infrared camouflage based on layered media

Infrared camouflage based on artificial thermal metasurfaces has recently attracted significant attention. By eliminating thermal radiation differences between the object and the background, it is possible to hide a given object from infrared detection. Infrared camouflage is an important element that increases the survivability of aircraft and missiles, by reducing target susceptibility to infrared guided threats. Herein, a simple and practicable design is theoretically presented based on a multilayer film for infrared stealth, with distinctive advantages of scalability, flexible fabrication, and structural simplicity. The multilayer medium consists of silicon substrate, carbon layer and zinc sulfide film, the optical properties of which are determined by transfer matrix method. By locally changing the thickness of the coating film, the spatial tunability and continuity in thermal emission are demonstrated. A continuous change of emissive power is further obtained and consequently implemented to achieve thermal camouflage functionality. In addition, other functionalities, like thermal illusion and thermal coding, are demonstrated by thickness-engineered multilayer films.

Sequential transformation of copper to porous copper (I) sulfide as superior electrode for supercapacitor

Herein, a highly porous copper (I) sulfide film is formed on the copper surface by employing a sequential chemical transformation. The material is characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy (XPS), and electrochemical analyses. The present method is simple, versatile, and economic for obtaining binder-free porous and highly conducting electrodes for an efficient supercapacitor. The supercapacitor of these electrodes with 3 M KOH electrolyte gives a high specific capacitance. The estimated specific capacitance is 1044 Fg−1 at 1.5 Ag−1 with retention close to 90% at the end of 3,000 cycles. The proposed method of making these electrodes can be easily scalable for mass production.

Highly Photosensitive Lead Sulfide Thin Films Grown by H2 S Free MOCVD Using a Single Source Metal-Organic Precursor.

High-quality lead sulfide (PbS)films are deposited on selected substrate chemistries by an H2 S-free metal-organic chemicalvapordeposition (MOCVD) process using a single-source metal-organic complex (Pb(dmampS)2 ). The complex is synthesized via a salt metathesis reaction betweenPbCl2 andlithium1-(dimethylamino)-2-methylpropane-2-thiolate (Li(dmampS))in diethyl ether. Subsequent film deposition is conducted by a simple thermolysis process in the absence of H2 S, yet chemical and structural analysis confirm chemically stoichiometric and homogenous films. Mechanistic studies with electron impact mass spectroscopy (EIMS) and gas chromatography mass spectroscopy (GCMS) suggest the selective cleavage of C-S bonds in the complex as the reason for the facile PbS formation with negligible impurity incorporation. The high crystallinity, low hole concentrations, and charge transport properties comparable and in many cases superior to films produced by atomic layer deposition (ALD) testify to the quality of the films. Lastly, rigid and flexible photodetectors fabricated with the PbS films exhibit considerably high photocurrents, reliable switching characteristics, and high sensitivity over a broad spectral bandwidth, highlighting the potential for realizing practical broadband photodetectors.

The Influence of Concentration on the Formation of Chemical Bath Deposited Copper Tin Sulphide Thin Films: SEM and EDX Studies

Nanostructured copper tin sulphide films have been deposited on the substrate (soda lime glass) via an economical chemical bath deposition method. The scanning electron microscopy (SEM) technique and energy dispersive X-ray analyzer (EDX) method were employed in this work to study the films’ morphology and composition. The EDX data and SEM images confirmed that the content of elements (sulfur, tin, and copper), the shape, and the grain size strongly depended on the concentration of the precursors during the formation of films. Experimental results revealed that a higher atomic percentage of the element could be observed for the films prepared using a higher concentration of solution during the experiment.

Bath temperature role in tailoring the properties of chemically bath deposited tin sulfide films

In this paper, the structural, optical and electrical properties of tin sulfide thin films are reported. Thin films are deposited (at different bath temperatures) by chemical bath deposition to investigate the role of bath temperature on the film properties. X-ray diffraction patterns reveal the structural phase transition from cubic to orthorhombic at 75 ºC bath temperature. FTIR spectra of cubic and orthorhombic films confirm dominant bond stretching of sulfur (S) and tin (Sn) atoms. Films deposited at different bath temperatures exhibit homogeneous and uniform surface morphology with surface roughness ≤ 45 ± 3 nm. Optical characterization shows that the cubic phase films have direct energy band gap (Eg) which is observed to be decreased (2.20 eV to 1.76 eV) with increasing bath temperature (55 ºC to 65 ºC). At 75 ºC bath temperature, the obtained film crystallizes in orthorhombic crystal structure and has an indirect optical energy band gap, Eg = 1.04 eV. A remarkable decrease in energy band gap is observed which is due to the structural phase transition (from cubic to orthorhombic) at 75 ºC bath temperature. Cubic and orthorhombic SnS films have electrical resistivity ρ ≤ 2.123 × 103 Ω.cm. Bath temperature is observed to play an important role in tailoring the crystal structure and energy band gap of chemically bath deposited tin sulfide thin films. Results suggest that the tin sulfide films can be deposited with required combination of properties for optical and energy harvesting devices.

Nickel sulfide film by potentiodynamic deposition as competent electrode for supercapacitor

Nickel sulfide film by potentiodynamic deposition as competent electrode for supercapacitor

Characterisation of Lead Sulphide (PbS) Films by Optical and Scanning Electron Microscopies

Characterisation of Lead Sulphide (PbS) Films by Optical and Scanning Electron Microscopies

Pulsed Laser Phosphorus Doping and Nanocomposite Catalysts Deposition in Forming a-MoSx/NP-Mo//n+p-Si Photocathodes for Efficient Solar Hydrogen Production.

Pulsed laser deposition of nanostructured molybdenum sulfide films creates specific nonequilibrium growth conditions, which improve the electrocatalytic properties of the films in a hydrogen evolution reaction (HER). The enhanced catalytic performance of the amorphous a-MoSx (2 ≤ x ≤ 3) matrix is due to the synergistic effect of the Mo nanoparticles (Mo-NP) formed during the laser ablation of a MoS2 target. This work looks at the possibility of employing a-MoSx/NP-Mo films (4 and 20 nm thickness) to produce hydrogen by photo-stimulated HER using a p-Si cathode. A simple technique of pulsed laser p-Si doping with phosphorus was used to form an n+p-junction. Investigations of the energy band arrangement at the interface between a-MoSx/NP-Mo and n+-Si showed that the photo-HER on an a-MoSx/NP-Mo//n+p-Si photocathode with a 20 nm thick catalytic film proceeded according to a Z-scheme. The thickness of interfacial SiOy(P) nanolayer varied little in photo-HER without interfering with the effective electric current across the interface. The a-MoSx/NP-Mo//n+p-Si photocathode showed good long-term durability; its onset potential was 390 mV and photocurrent density was at 0 V was 28.7 mA/cm2. The a-MoSx/NP-Mo//n+p-Si photocathodes and their laser-based production technique offer a promising pathway toward sustainable solar hydrogen production.

Study of the quasi-single crystalline lead sulfide film deposited by magnetron sputtering and its infrared detecting characteristics

Study of the quasi-single crystalline lead sulfide film deposited by magnetron sputtering and its infrared detecting characteristics