Barium titanate is a ferroelectric perovskite with unique electric properties; therefore, it is widely applied in the fabrication of inorganic coatings or thin films, capacitors, or in the production of devices for energy storage and conversion. This paper describes the mechanochemical synthesis of BaTiO₃ from BaO and TiO₂ using a ball mill. XRD analysis allowed concluding that barium titanate was formed after 90 min of mechanochemical grinding. It was also proved by spectroscopic analysis and the band corresponding to Ti–O vibrations on obtained Fourier Transform Infrared (FT-IR) spectra. The specific surface area of obtained powder was 25.275 m²/g. Next, formed perovskite was dispersed in an acrylic poly(ethylene glycol) (superabsorbent polymer suspension, SAP) suspension prepared using microwave radiation. Final suspensions differed in the concentration of SAP applied. It was proven that the increase of SAP concentration does not affect the acidity of the suspension, but it does increase its dynamic viscosity. A sample with 83 wt.% of SAP reached a value of approximately 140 mPa∙s. Dispersions with higher values of SAP mass fraction exhibited lower sedimentation rates. Molecules such as SAP may adsorb to the surface of particles and thus prevent their agglomeration and make them well monodispersed. Based on the performed experiments, it can be concluded that acrylic poly(ethylene glycol) suspension is a suitable fluid that may stabilize barium titanate dispersions.

In this paper, we investigated the optical and thermo-optical properties of a-SiN_x:H layers obtained using the PECVD technique. SiN_x:H layers with different refractive indices were obtained from silane and ammonia as precursor gases. Surface morphology and chemical composition studies were investigated using atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectrometry methods. Spectroscopic ellipsometry was used to determine the optical indexes, thicknesses and optical bandgap of the films. The main purpose was to identify the thermo-optical characteristics of layers with different refractive indexes. Thermo-optical studies were performed to determine the temperature hysteresis of optical parameters. These measurements showed that after annealing up to 300 °C and subsequent cooling, the value of optical parameters returned to the initial values.

This paper presents the results of investigations of optical scattering phenomena in porous silica films. SiO₂ films were prepared by the sol-gel method and deposited on polished silicon wafers by the dip-coating technique. Fabricated films were studied using integrating sphere reflectometry, spectroscopic ellipsometry, atomic force microscopy, scanning electron microscopy, and angular resolve scattering. The spectral characteristics of the refractive and extinction indices and scattering extinction coefficients are presented. Additionally, the depolarization of reflected beam from samples was measured. The tested films were characterized by a thickness of 500 to 900 nm, a porosity of 50%, and refractive indices of less than 1.24. The observed depolarization of light reflected from SiO₂ films resulted from surface and bulk scattering. This phenomenon resulted from the presence of surface and closed pores located in the bulk of SiO₂ film.

The aim of this work was the determination of the basic optical parameters and electronic structure of conjugated polymer films by two commonly used techniques—spectrophotometry and ellipsometry. Poly(3-hexylthiophene (P3HT) and poly(3-octylthiophene (P3OT) conductive polymers films deposited on a glass substrate by the spin-coating technique showed very comparable surface structures composed of grains of similar sizes and shapes. X-ray tests confirmed that the polythiophene layers are amorphous, which confirmed the correctness of the choice of the optical models used. Selected optical models (Lorentz, Tauc–Lorentz and Cody–Lorentz) have been applied in order to determine the thickness, and optical parameters such as refractive index and extinction coefficient, absolute absorption and electronic parameters (energy gap E_g, amplitude A and broadening B). Spectral absorption determined from spectrophotometric measurement is similar to the absorption spectrum obtained from the ellipsometry method with the application of oscillator models.

It has been demonstrated that apart from the known compounds YbVO₄ and Yb₈V₂O₁₇, a substitutive solid solution is also formed in the binary oxide system V₂O₅–Yb₂O₃. This solid solution is characterized by limited solubility of vanadium(V) oxide in the crystal lattice of ytterbium oxide, and its general formula is Yb_2−5x□_2xV_3xO₃, where 0.00 < x < 0.1667. The new solid solution was obtained from the mixtures of V₂O₅ and Yb₂O₃ oxides, containing vanadium(V) oxide in the amounts not exceeding 30 mol%, by high-energy ball milling in a planetary ball mill. The solid solution obtained was characterized using the methods XRD, DTA-TG, SEM, IR and UV–Vis-DR. It was found to crystallize in cubic system and to show a structure of Yb₂O₃. This solid solution was stable in air atmosphere at least up to ~ 800 °C, and the temperature of its decomposition decreased with increasing x, so with increasing degree of Yb³⁺ replacement with V⁵⁺ in the crystal lattice of Yb₂O₃. The energy gap estimated for this solid solution varied from ~ 2.5 eV for x = 0.0322 to ~ 2.6 eV for x = 0.1176, which means that this new solid solution is a semiconductor.