Search

This paper investigates on synthesis and structural, optical and magnetic properties of SnFe2O4 spinel/graphene oxide (GO)/rGO nanocomposites by sol–gel, microwave and co-precipitation methods. The synthesis of these nanoparticles was achieved through simple and cost-effective methods. A variety of techniques including X-ray diffraction (XRD), UV–Vis spectroscopy, Field emission electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), and vibrating sample magnetometer (VSM) were utilized to analyse the nanoparticles. By using the crystallography different methods like Scherer, Rietveld, and Williamson-Hall, various structural properties were studied. The X-ray diffraction patterns indicated the peaks presence corresponding to graphene oxide (GO), reduced graphene oxide (rGO) and SnFe2O4 spinel phase in the SnFe2O4 / GO and rGO nanocomposites. The peak with the highest intensity in the (311) direction was found in the SFO/rGO nanocomposite. Additionally, morphology images by FESEM showed the formation of small cube-shaped and polyhedral structures for SnFe2O4 phase and GO and rGO as nano plates. Optical properties such as refractive index, extinction coefficient, dielectric constant, Urbach energy, and reflection coefficient were analysed using UV–Vis spectroscopy. The optical analysis results show that the SnFe2O4/rGO nanocomposite had the highest level of light absorption with band gap in range Eg = 2.28–3.21 eV as wide band gap semiconductor. The Vibrating-sample magnetometer (VSM) analysis showed that samples containing tin ferrite exhibited ferromagnetic behaviour. FTIR analysis identified metal oxide peaks (Sn–O) and (Fe–O) in the nanoparticle samples, while organic bonds such as hydroxyl, epoxide, carbonyl, and carboxylic were found in GO and rGO nanocomposite samples. [ABSTRACT FROM AUTHOR]

In this study, tin ferrite nanoparticles (SnFe2O4) were synthesized using sol–gel, solvothermal, and co-precipitation methods, and the effect of annealing temperature on the formation of structures annealed at T = 350 °C, T = 450 °C, and T = 550 °C was investigated. The X-ray diffraction (XRD), UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and field-emission electron microscopy (FESEM) were used to investigate the structural, optical, and surface morphological properties. The results obtained from the structural analysis of the synthesized samples showed that the SFO4 sample with the spinel phase synthesized by solvothermal had the highest intensity of the preferred peak (311) and a more uniform grain size. The FESEM images of the nanostructures showed cubic and polyhedral grains with cluster growth. The optical absorbance of the samples was studied using UV–Vis spectroscopy within the wavelength range of λ = 190–1100 nm. The highest absorption in the samples was related to SFO6, and the band gap showed an increasing trend with temperature in region Eg = 2.20–2.85 eV. The reason for the increase of band gap with increasing temperature is the formation of independent oxide phases in the nanoparticle's composition. The tin ferrite oxide spinel sample SFO4 showed a value of 2.53 eV. From the UV–Vis analysis, the values of refractive index (n), extinction coefficient (k), dielectric constant (ϵ ), Urbach energy (Eu) and reflection coefficient were studied. The results of the FTIR analysis in the fingerprint region confirm the vibrations caused by the presence of Sn–O and Fe–O metal oxides. The presence of metal oxide bonds indicates the formation of tin ferrite structure. [ABSTRACT FROM AUTHOR]

In this study, polyaniline (PANI)/SnO2, and polyvinyl-alcohol (PVA)/PANI/SnO2 nanocomposite as polymer hybrid electrodes were synthesized from tin chloride precursor and PANI/PVA polymer by sol–gel solution method. Also, for comparison, the SnO2:F (transparent conductive oxide, FTO) and aluminium (Al) on PET substrate as metallic flexible electrodes were deposited by thermal vacuum evaporation and spray pyrolysis methods. Two different molar concentrations were used to synthesize PANI/SnO2 conductive electrodes. The conductive polymer nanocomposites and polymeric electrodes were characterized by XRD analysis, FE-SEM imaging, UV–Vis and FTIR spectroscopy. In the synthesized PANI/SnO2 nanocomposite with a larger amount of SnO2 solution (15 ml), the sharp peaks of PANI are completely removed. The XRD results for FTO/PET showed that at T = 200°C, the amorphous spectrum decreased sharply due to a decrease in the PET peak. Also, the peaks of SnO2 with the tetragonal and cubic structures were observed with the preferred direction (110). FE-SEM images of FTO thin films deposited on the PET polymer substrate at T = 200°C showed that the flat plates formed by bonding of SnO2 nanoparticles formed on the polymer substrate. Also, the optical bandgap of the PANI/SnO2 nanocomposite showed that with increasing the volume of SnO2 solution, the amount of energy gap increases. The results of FTIR spectroscopy showed that with increasing SnO2, there is no difference in the type of factor group and only affects the intensity of the peaks and leads to a little shift of the peaks to the modes of pure polyaniline. [ABSTRACT FROM AUTHOR]

In this paper, SnO2: rGO compound thin films were deposited on glass substrates by spray pyrolysis method. For the synthesis of SnO2: rGO thin films, different amounts of reduced graphene oxides (0, 25, 50, 75, 100, and 150 mg) were added to the solution. Then, the influence of reduced graphene oxide, and annealing by hydrazine as a reducing agent on the structural, electrical, and optical properties of these films were investigated. The results of XRD analysis in all the samples showed the SnO2 phase is formed and the intensity of peaks increases relatively after reducing with hydrazine and increasing the value of rGO. FE-SEM images of SnO2: rGO samples showed that grain size and porosity decreased after reduction with hydrazine. An enhancement of electrical properties was observed with the addition of reduced graphene oxide and annealing under hydrazine. The minimum sheet resistance equal to 0.42 kΩ/sq. for SnO2: rGO (50 mg) thin films was obtained. The Hall effect experiment also showed the n-type conductivity of all synthesized thin films, and the carrier concentration was calculated to be 1021 cm−3. In addition, the band gap values of the films in the range of 3.58–3.72 eV were obtained and this method is a successful technique for tuning of the band gap of SnO2 thin films. [ABSTRACT FROM AUTHOR]