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Multicomponent equimolar perovskite oxides (ME-POs) have recently emerged as a highly promising class of materials with unique synergistic effects, making them well-suited for applications in such areas as photovoltaics and micro- and nanoelectronics. High-entropy perovskite oxide thin film in the (Gd0.2Nd0.2La0.2Sm0.2Y0.2)CoO3 (RECO, where RE = Gd0.2Nd0.2La0.2Sm0.2Y0.2, C = Co, and O = O3) system was synthesized via pulsed laser deposition. The crystalline growth in an amorphous fused quartz substrate and single-phase composition of the synthesized film was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Surface conductivity and activation energy were determined using a novel technique implementing atomic force microscopy (AFM) in combination with current mapping. The optoelectronic properties of the deposited RECO thin film were characterized using UV/VIS spectroscopy. The energy gap and nature of optical transitions were calculated using the Inverse Logarithmic Derivative (ILD) and four-point resistance method, suggesting direct allowed transitions with altered dispersions. The narrow energy gap of RECO, along with its relatively high absorption properties in the visible spectrum, positions it as a promising candidate for further exploration in the domains of low-energy infrared optics and electrocatalysis.

Various amounts of Al2O3 (0.25, 0.5 and 1.0mol%) were added to tetragonal polycrystalline material (3YTZP), prepared using the hydrothermal crystallization method. The effects of the added amount as well as the sintering temperature on the microstructure and electrical properties of the 3Y-TZP/Al2O3 composites were investigated. The alumina addition was found to affect the microstructure of the 3Y-TZP samples obtained after sintering at 1400 or 1500?C only to a slight extent. The lowest values of the blocking factor, which represents the contribution of grain boundary resistivity to the total resistivity of a polycrystal, were observed for the 3Y-TZP with Al2O3 additions of 0.25 or 0.5mol% at measurement temperatures of 550 and 600 ?C. The study proves that the 3Y-TZP/Al2O3 should be taken into consideration as solid electrolyte in the intermediatetemperature solid oxide fuel cells.

In this work, a new carbon paste electrode (CPE) was presented, in which as a binder picein hard wax was applied. Picein wax combines the features of high plasticity at temperatures above 90 °C as well as hardness and chemical resistance at room temperature. Repeated polishing and usage, without losing the quality of the electrode working surface, is possible and gives the effect of a high level of signal repeatability. Picein-based electrode was applied in europium(III) determination by differential pulse voltammetry in the optimized supporting electrolyte (mixture of NaClO4 and HClO4). It was proved that addition of HClO4 is necessary; otherwise, double-peak effect is observed. In voltammetric experiments, activation of the electrode surface, by applying a potential of 1600 mV for several seconds, is recommended. It was demonstrated that for concentration 1–10 μM of Eu(III), sensitivity was 0.0301 ± 0.0004 μAμM−1 with correlation r = 0.9996 and limit of detection 0.3 μM.

V2O5 thin films have been deposited onto an insulating support by radiofrequency (rf) reactive sputtering from a metallic vanadium target at controlled flow rates of argon–oxygen gas mixture. Glancing-incidence x-ray diffraction (GIXD) analysis and scanning electron microscopy (SEM) were used for structural and phase characterization of the obtained materials. The as-sputtered thin films were found to consist of orthorhombic V2O5 phase. Electrical properties were determined by electrochemical impedance spectroscopy (EIS) conducted over the frequency range of 0.1 Hz to 1.4 MHz and temperatures ranging from room temperature (RT) to 773 K. Between RT and 528 K, the recorded impedance spectra were interpreted in terms of an equivalent circuit composed of a resistor and non-Debye constant-phase element (CPE) connected in parallel. In this temperature range, the material exhibited n-type extrinsic conductivity. The activation energy of electrical conductivity was 0.243 ± 0.023 eV. At 528 K, an abrupt change in resistivity was observed, interpreted as a metal–insulator transition (MIT). Above 528 K, the equivalent circuit was composed of a resistor (R) and inductor (L) connected in series, typical of materials exhibiting metallic properties.

The lanthanum strontium cobalt ferrite (LSCF)-Ag composite cathode material was prepared in aqueous solution by new one-step method. In this method silver nanoparticles obtained by the reduction of [Ag(NH3)2]+ complex with sucrose were directly deposited onto the surface of LSCF powder. UV–Vis spectra of supernatant solution taken during synthesis showed the presence of a sharp excitation band near 397 nm attributed to the surface plasmon excitation of silver nanoparticles. Obtained composite powder was sintered to samaria doped ceria electrolyte in one step sintering procedure at 1000 °C. The presence of silver in LSCF cathode facilitates the oxygen reduction. The comparison of impedance spectra of LSCF-Ag cathodes with spectra reported in literature for similar LSCF cathodes shows that this effect is important at lower oxygen partial pressures. The analysis of the electrochemical impedance spectra recorded in the range 10−2–1010 Hz reveals that the second high frequency semicircle ascribed to the electrolyte grain boundary impedance is distorted due to process belonging to oxygen reduction reaction.

Silver is one of the most promising cathode materials for low temperature (300–500 °C) solid oxide fuel cells. The most important disadvantage of silver is its migration in the electric field. For better understanding of this phenomenon, an in situ observation of the migration mechanism was undertaken with the use of high-temperature microscopes. Scandia stabilised ceria doped zirconia CeScSZ electrolyte prepared from commercial powder was examined before and after silver migration experiments using scanning electron microscope. X-ray diffraction, broadband electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. The silver electrodes for solid oxide fuel cells were prepared using magnetron sputtering. The described cells under polarisation were examined using a high-temperature low energy electron microscope. Reference cells and post-mortem cells were observed using a scanning electron microscope equipped with high temperature stage. Under polarisation, silver moved inside the electrolyte and along the surface towards the region between electrodes. The structures thus formed were similar to those previously described in the literature; however, direct observation of the deposit growth was unsuccessful. In situ scanning electron microscopy observations of the silver electrode at 650 °C revealed neither melting of the smallest silver particles nor movement of silver structures. Silver migration through the electrolyte caused a reduction in grain interior conductivity of the electrolyte, whereas its grain boundary conductivity remained unaffected.

The preparation and sintering conditions of the selected rare-earth oxychlorides REOCl (Re=La, Nd, Sm, Gd) were determined. The purity of materials phase compositions was confirmed by X-ray diffraction method. Further analysis of the data enabled lattice parameters and average grain size determination. The electrical properties of the single phase REOCl materials were investigated by Electrochemical Impedance Spectroscopy in wide temperature range in atmospheric air. The spectra were analyzed by the equivalent circuit fitting. Basing on the values of equivalent circuits parameters the specific conductivities were calculated and presented in the Arrhenius coordinates. Energies of activation were calculated. The determined structural and electrical properties of four different rare-earth oxychlorides were directly compared.

The aim of this work was examination of gadolinium-doped 3YSZ electrical and structural properties. Such materials may be used as electrolytes in intermediate temperature solid oxide fuel cells (IT-SOFC). First step of the research was synthesis of 3YSZ with different contents of gadolinium (0.25; 0.5; 1.0 at %). Prepared materials were characterized by high porosity. No effect of gadolinium addition on grain size was observed. The experimentally determined values of grain interiors electrical conductivities for gadolinium doped samples are comparable to grain interior conductivities of gadolinium free tetragonal zirconia. On the other hand, a clear effect of gadolinium addition on electrical conductivity of grain boundaries was observed. It was found that 3YSZ containing 0.25 at. % Gd was the most promising from the investigated materials as a solid electrolyte for IT SOFC.

The ammonia sensing properties of BiFeO 3 (BFO) multiferroic semiconductor were investigated. The material was prepared by solid state reaction method. The sintered sample was studied by X-ray diffraction analysis (XRD), Raman Spectroscopy and Scanning Electron Microscopy (SEM). Electrical conductivity of BFO was determined by Electrical Impedance Spectroscopy (EIS) in temperature range 100–700 °C at different gaseous atmospheres. The BFO resistance responses to ammonia concentrations of 0–2100 ppm in argon were recorded in the temperature range of 300–600 °C. Similar measurements were carried out in atmosphere containing 0–2100 ppm ammonia in synthetic air in temperature range of 350–450 °C. The effect of water vapor on sensor performance was investigated. The sensor working mechanism has been explained.

La 1-x Mg x OCl 1-x (x = 0.025, 0.05 and 0.1) and La 0.9 Ca 0.1 OCl 0.9 samples were prepared by a solid state reaction method. The best preparation conditions were determined by means of the differential thermal analysis and thermogravimetry (DTA&TG). The samples were studied by X-ray diffraction (XRD) analysis. Electrical conductivity of La 0.9 Mg 0.1 OCl 0.1 was measured using electrical impedance spectroscopy (EIS). The prototype chlorine gas sensor was constructed from La 0.9 Mg 0.1 OCl 0.1 solid electrolyte. The source voltage (SV) of the constructed device was measured as a function of temperature (500–800°C), Cl 2 gradient partial pressure and time. Similar measurements of SV was carried out in atmosphere of synthetic air in argon.