XRD and UV-Vis Spectroscopic Studies of Lead Tin Sulphide (PbSnS) Thin Films

The effects of deposition cycles on the structural and optical properties of lead tin sulphide (PbSnS) thin films have been described. Successive ionic layer adsorption and reaction (SILAR) method was used to deposit the ternary material on soda-lime substrates. In the present work, the PbSnS films were grown using lead nitrate, tin chloride dehydrate and thioacetamide solutions as sources of Pb, Sn and S, respectively. XRD measurements revealed that the deposited films were polycrystalline in nature with strong adherent to the substrates. The transmittance was found to be high in the near infrared regions of the electromagnetic radiation and, also increased with deposition cycles. The band gap energy was found to vary from 1.70 to 1.75 eV for 10 and 35 deposition cycles. The study indicates that SILAR is an excellent method in depositing good quality films for device applications. HIGHLIGHTS SILAR is an excellent technique for depositing thin films of lead tin sulphide (PbSnS) Deposition cycles influences the XRD and optical properties of PbSnS thin films PbSnS thin films are useful for solar cell fabrications The band gaps of the PbSnS varies from 1.70 to 1.75 eV with deposition cycles

Conductive Polymer Composites for Hydrogen Sulphide Sensors Working at Sub-PPM Level and Room Temperature

Hybrid composites based on tin chloride and the conductive polymers, polyaniline (PAni) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), were integrated into high-performance hydrogen sulphide (H2S) gas sensors working at room temperature. The morphology and chemical properties were studied by scanning and transmission electron microscopy (SEM, TEM), energy dispersive spectroscopy (EDS) and Fourier-transform infrared (FTIR). The composites demonstrated a slightly porous nanostructure and strong interactions between the polymers and the metal salt, which slightly dopes PAni. The hybrid sensors exhibited a very low detection limit (<85 ppb), fast response, repeatability, reproducibility and stability over one month. Moreover, this work presents how calibration based on the derivative of the signal can give hybrid sensors the ability to quantify the concentration of targeted gas, even during continuous variation of the analyte concentration. Finally, the effect of interfering species, such as water and ammonia, is discussed.

PREPARATION OF ATO NANOPOWDERS WITH Co-PRECIPITATION AND THEIR LASER-REFLECTION PROPERTIES

Antimony tin oxide (ATO) nanoparticles were prepared using co-precipitation with tin chloride and antimony chloride as the main raw materials. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and ultraviolet-visible spectrophotometry were used to characterize the crystal structure, morphology and laser reflectivity. The effects of the pH value, co-precipitation reaction temperature, calcination temperature and calcination time on the laser reflectivity of ATO nanoparticles were studied. The results show that, compared with the undoped SnO2 powder, the reflectivity of a Sb-doped ATO powder at a laser wavelength of 1.06 µm is significantly reduced, and with an increase in the Sb doping, the reflectivity of the ATO powder at 1.06 µm first decreases and then increases. When the Sb/Sn molar ratio is 2/10, the reflectivity decreases to the lowest point, which is caused by the high concentration of Sb5+. ATO powders (Sb/Sn = 2/10) prepared at a titration-end-point pH of 2, co-precipitation temperature of 70 °C, calcination temperature of 800 °C and calcination time of 6 h have the lowest laser reflectivity at the laser wavelength of 1.06 µm, which is less than 0.02 %.

CuO/SnO2 Nanocomposite Thin Films: Effect of Solvent and Precursor on Optical and Structural Properties

New materials nanocomposites were synthesized for the degradation of organic and inorganic pollutants. This study reviews CuO/SnO2 nanocomposite thin films for their photocatalytic effect. The latter were deposited using the spray pyrolysis method, which is a simple, cheapest and rapid technique. Different concentration ratios of precursors and solvent are used. The thin films were deposited on ordinary glass substrates heated to 550∘C from solutions of copper chloride and tin chloride as precursors. The optical and structural properties of nanocomposite thin films have been demonstrated, and the equi-percentage of the precursor combination shows the good bandgap energy according to the literature. Investigations of structural properties using (SEM, EDS, XRD and RAMAN) techniques depict the good agreement photocatalytic degradation according to the surface roughness, quantities of elements and the existence of phases which will be of interest to the photocatalytic of organic and inorganic pollutants in aqueous and gas media according to the huge specific area due to the roughness and heterogeneity.

Soluble tungsten compounds Determination in workplace air

Tungsten is a transition metal which occurs in the Earth’s crust as minerals which after being mined is extracted. There is no data on chronic effects of contact with tungsten, although fine tungsten powder is flammable and can cause mechanical irritation to skin and eyes. However, there are soluble tungsten compounds, which are classified as toxic, causing damage to the eyes, and being harmful to the aquatic environment. The aim of the study was to amend Standard No. PN-Z-04221-3 determination of soluble tungsten compounds in workplace air using spectrophotometric method with potassium thiocyanate. The amendment was performed because Standard No. PN-Z-04221-3 describes a method in which the quantification is 0.25 mg/m3, according to European Standard No. EN 482 the quantification of method must be in range of 0.1 – 2 mg/m3. The method is based on depositing soluble tungsten compounds on a cellulose esters filter and then dissolving them in water. Then tungsten is reduced with tin chloride, after reaction with potassium thiocyanate, tungsten becomes a complex. Tungsten complex should be extracted with isoamyl alcohol and then absorbance should be measured on a UV-Vis spectrophotometer. The tests were performed with the UV-Vis Heλios spectrophotometer by ThermoSpectronic model Beta. The validation requirements of European Standard No. EN 482 were met. With this method soluble tungsten compounds in air can be determined at concentration of 0.1 – 2 mg/m3. The limit of quantification (LOQ) is 1.875 ng. The overall accuracy of the method is 5.06% and its relative total uncertainty is 22.09%. The method for determining tungsten has been recorded in a form of an analytical procedure (see Appendix). This article discusses problems of occupational safety and health, which are covered by health sciences and environmental engineering.

Tin-Naphthalene Sulfonic Acid Complexes as Photostabilizers for Poly(vinyl chloride)

Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%–95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.

Synthesis of Cu2ZnSnS4 (CZTS) Ink by an Easy Hydrothermal Method

The quadrilateral p-type semiconductor Cu2ZnSnS4 (CZTS) with a direct bandgap of 1.4 to 1.5 eV and a high absorption coefficient in the visible light range, is considered an excellent absorbent layer in the production of solar cells. The application of Cu2ZnSnS4 film absorbent materials is promising in the field of low-cost solar cell production. In this paper, a simple, efficient, controllable, and inexpensive solvothermal method is used to make the CZTS nanoparticles from zinc acetate, copper acetate, tin chloride, thiourea, and hexadecyl amine solvent. The ink was prepared from the CZTS powder and applied by the doctor Blade technique on soda-lime glass. The X-ray diffraction (XRD) and Raman spectroscopy analysis showed that the CZTS synthesis nanoparticles had a pure Kesterite structure. The thermo-gravimetric analysis showed about 12% of the loss weight of CZTS nanoparticles using field emission scanning electron microscopy, energy dispersive spectroscopy, dynamic light scattering, and zeta potential indicated that the synthesized nanoparticles had a strong absorption in the range of 125–477 nm with an average particle size of 300 nm and plate shape. The energy bandgap of CZTS nanoparticles was measured to be 1.49 eV using UV-Vis spectroscopy.