Wiktor Matysiak

Manufacturing and investigation of physical properties of polyacrylonitrile nanofibre composites with SiO2, TiO2 and Bi2O3 nanoparticles

Summary The aim of this study was to produce nanocomposite polymer fibres, consisting of a matrix of polyacrylonitrile (PAN) and a reinforcing phase in the form of SiO2/TiO2/Bi2O3 nanoparticles, by electrospinning the solution. The effect of the nanoparticles and the electrospinning process parameters on the morphology and physical properties of the obtained composite nanofibres was then examined. The morphology of the fibres and the dispersion of nanoparticles in their volume were examined using scanning electron microscopy (SEM). All of the physical properties, which included the band gap width, dielectric constant and refractive index, were tested and plotted against the concentration by weight of the used reinforcing phase, which was as follows: 0%, 4%, 8% and 12% for each type of nanoparticles. The width of the band gap was determined on the basis of the absorption spectra of radiation (UV–vis) and ellipsometry methods. Spectroscopic ellipsometry has been used in order to determine the dielectric constant, refractive index and the thickness of the obtained fibrous mats.

Analysis of optical properties of TiO2 nanoparticles and PAN/TiO2 composite nanofibers

ABSTRACT The aim of the study was the production of thin composite nanofibrous mats PAN/TiO2 nanoparticles using the electrospinning method from solution of PAN/TiO2/DMF. TiO2 nanoparticles were obtained using sol-gel method. To prepare sol mixture, organic alkoxides precursor of titanium isopropoxide and water solution were used. Calcination of TiO-gel and following milling were carried out to obtain nanoparticles of TiO2 rutile phase. In order to analyze the structure of the obtained particles, we used X-ray diffraction analysis (XRD) and energy dispersive spectrometer (EDS). Analysis of the morphology and chemical composition of the resulting composite nanofibers were carried out using a scanning electron microscope (SEM) with EDS. The analysis of the optical properties and the energy band structure prepared nanoparticles and thin composite nanofibrous mats were determined by spectral analysis of the absorbance as a function of the energy of radiation obtained using a UV–Vis spectrophotometer.

Using of sonochemically prepared SbSI for electrospun nanofibers

A novel polymeric, polyacrylonitrile (PAN) nanofibers containing ferroelectric and semiconducting antimony sulfoiodide (SbSI) have been made by electrospinning. SbSI nanowires, used as the filler, have been prepared sonochemically from antimony sulphide (Sb2S3) and antimony tri-iodide (SbI3) for the first time. Nanocrystalline SbSI has been fabricated in ethanol under ultrasonic irradiation (20kHz, 565W/cm2) at 323K within 2h. The products have been characterized by using techniques such as powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, high-resolution transmission electron microscopy, selected area electron diffraction and optical diffuse reflection as well as transmission spectroscopy. The good quality of the nanocrystals and their dispersion in the nanofibers volume is important because this material is attractive for nanogenerators due to its ferroelectric and piezoelectric properties. The amplitude of the voltage pulse, generated under shock pressure of 3.0MPa, has reached 180V in the prototype PAN/SbSI piezoelectric nanogenerator. The peak output voltage of about 0.2V was measured in bending/releasing conditions with the deformation frequency of 1Hz.

Analysis of the Optical Properties of PVP/ZnO Composite Nanofibers

The aim of this study was to produce nanocomposites polymer fibers, with the participation of the reinforcing phase in the form of ZnO nanoparticles with a matrix of polyvinylpyrrolidone (PVP), made by electrospinning. Furthermore, examining the impact of the concentration of reinforcing phase on the optical properties of the obtained composites nanofibers. The morphology of nanofibers was examined by atomic force microscope and it showed that the applied process parameters gave the polymer fiber mats PVP from 10 % solution PVP/EtOH and composites PVP/ZnO from 10 % solution, wherein the concentration by weight of the used reinforcing phase was as follow: 5 and 10 %. To improve the influence of the concentration by weight of the used reinforcing phase on the optical properties, the spectroscopy UV-Vis has been used.

Synthesis of the Novel Type of Bimodal Ceramic Nanowires from Polymer and Composite Fibrous Mats

The purpose of this paper was to produce SiO2 and TiO2 nanowires via the electrospinning process from a polyvinylpyrrolidone (PVP)/Tetraethyl orthosilicate (TEOS)/Titanium (IV) butoxide (TNBT)/dimethylformamide (DMF) and ethanol (EtOH) solution. The as-obtained nanofibers were calcined at temperatures ranging from 400 °C to 600 °C in order to remove the organic phase. The one-dimensional ceramic nanostructures were studied using a scanning electron microscope (SEM) and a transmission electron microscope (TEM) to analyze the influence of the used temperature on the morphology and structures of the obtained ceramic nanomaterials. In order to examine the chemical structure of the nanowires, energy dispersive spectrometry (EDX) and Fourier-Transform Infrared spectroscopy (FTIR) were used. The optical property analysis was performed on the basis of UV-Vis spectra of absorbance as a function of the wavelength. Using the modified Swanepoel method, which the authors proposed and the recorded absorbance spectra allowed to determine the banded refractive index n, real n′ and imaginary k part of the refractive index as a function of the wavelength, complex dielectric permeability ε, and real and imaginary part εr and εi of the dielectric permeability as a function of the radiation energy of the produced ceramic nanowires.

Manufacture of photovoltaic cells with hybrid organic–inorganic bulk heterojunction

ABSTRACT The aim of this paper is to present the influences of material composition and production conditions of the photovoltaic cells on its parameters as well as the active layer properties. The layers were made of organic compounds: metal phthalocyanine/perylene derivatives. In addition, the effects of TiO2 and SiO2 nanoadditives were investigated. The materials used are selected so as to allow P–N junction creation. Deposition technique allows at simultaneous applying the materials leads to obtaining homogeneous dispersion of one material in the other, which determines the formation of bulk P–N junctions. Research includes the estimate of share of individual components in the active layer, then determination of the morphology of surface and optical properties of the same layer and its implementation in photovoltaic structures. The structural researches and morphology of surface investigation were made using transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The optical properties were researched with the use of UV–Visible spectroscope. The parameters of cells have been determined on the basis of current–voltage characteristics. The work undertaken within the framework of article allowed to linking properties of active layers with the parameters of the same cells.

Manufacturing process and optical properties of zinc oxide thin films as photoanode in DSSC

Purpose: It has been recently observed, that zinc oxide thin films are gaining much popularity, particularly in applications such as toxic gas sensors, photocatalytic materials and photovoltaic cells. Due to much better physical properties of ZnO compared to the ones of titanium dioxide (TiO2), which is currently the most used material in dye sensitized solar cells, efforts are being made to fabricate DSSCs with thin films and/or nanostructures, including nanowires, nanofibres and nanoparticles of zinc oxide. Design/methodology/approach: In this paper, zinc oxide thin films were prepared using sol-gel and spin coating methods from Zn(COO)2 x 2H2O dissolved in ethanol and acetic acid with ZnO monocrystalline nanoparticles of 0 and 10% (wt.) relative to the final concentration of produced solutions. The effect of calcination process on ZnO thin films at 600°C were examined using atomic force microscope to investigate the morphology of semiconductor coatings, infrared spectroscopy to prove the chemical structure of material. Besides, optical properties were analysed on the basis of absorbance in the function of wavelength spectra and the values of energy band gaps were studied. Findings: The topography analysis of ZnO thin films showed an increase in roughness with the increase of zinc oxide nanoparticles in the thin films material. In addition, the analysis of the optical properties of ZnO thin films showed a decrease in absorption level in the range of near-ultraviolet wavelength for the obtained layers after annealing. Research limitations/implications: It was found that ZnO thin films produced by spin coating and calcination method are a proper material for photoanode in dye-sensitized solar cells, as zinc oxide layers provide better conductivity across the photovoltaic cell. Practical implications: The results provide the possibility of production DSSCs with zinc oxide thin films as photoanode. Originality/value: The dye-sensitized solar cells based on zinc oxide photoanodes could be alternative semiconductor material to titanium dioxide, which is used in nowadays solar cells. It was estimated that ZnO, especially zinc oxide nanostructures have much better physical properties, than TiO2 structures. What is more, zinc oxide thin layers are characterized by the lower energy losses resulting from the physical properties of such nanostructures, which results in more efficient solar energy into electricity conversion.

Preparation and investigations of electricaland optical properties of thin compositelayers PAN/SiO2, TiO2 and Bi2O3

Purpose: The aim of this study was to present the influence of mass concentration of the reinforcement phase on the structure and optical properties of the obtained composite thin films with a polymer matrix reinforced by SiO2, TiO2 and Bi2O3 nanoparticles, produced by the spin-coating method. Design/methodology/approach: To produce composite materials, 10% wt. polymer solutions of polyacrylonitrile (PAN) and N, N Dimethyloformamide (DMF) were used, containing nanoparticles with a mass concentration ratio of, sequentially: 0, 4, 8, 12%. The morphology, structure and chemical composition of the obtained thin films were determined on the basis of surface topography images, taken using atomic force microscopy (AFM) and a scanning electron microscope (SEM) with EDX and QBSD spectrometers. In order to analyse the optical properties, UV-Visible spectroscopy (UV-Vis) was used. The width of the band gap was determined on the basis of the absorption spectra of radiation (UV-Vis). Findings: The carried out morphology and surface structure research showed that with increasing mass increased porosity of the produced coating surface was observed. In addition, the greater the diameter of the applied ceramic nanoparticles, the more noticeable this effect was. The analysis of the optical properties of the obtained nanomaterials, carried out based on the registered spectra in absorption function of the wavelength, revealed a strong absorption of this type of layers under ultraviolet radiation. Research limitations/implications: The nanostructured materials as components provides nanocomposite optical properties, such as absorption and width of the energy gap. In addition, nanoparticle content causes changes of the surface morphology, which is an important parameter of thin films in potential applications. Originality/value: The properties of films depend not only on the individual components used, but also on the morphology and the interfacial characteristics.