TiO₂–SiO₂ nanocomposite thin films have gained the attention of the scientific community due to their unique physical and chemical properties. In this paper, we report on the fabrication and characterization of a TiO₂–SiO₂ nanocomposite disk-shaped target. The target was used for the deposition of TiO₂–SiO₂ nanocomposite thin films on fluorine-doped tin oxide/glass substrates using the pulsed laser deposition (PLD) technique. The thicknesses of the thin films were fixed to 100 nm, and the deposition temperature ranged from room temperature to 300 °C. As revealed by the microstructural and morphological characterizations revealed, the TiO₂–SiO₂ nanocomposite thin films are amorphous and display homogeneous distribution. The determined values of the indirect optical band gap range from 2.92 to 3.07 eV, while those of the direct optical band gap lie between 3.50 and 3.55 eV. Additionally, as the deposition temperature decreases, the light transmission increases in the visible and in the ultraviolet ranges, which is suitable for flexible perovskite solar cells. This research can uncover new insights into the fabrication of amorphous TiO₂–SiO₂-based nanostructured thin films using the PLD technique for perovskite solar cell technology.

This paper presents the synthesis of gadolinium aluminate (GdAlO₃), an oxide compound with a perovskite structure, for applications as a capacitive and/or resistive humidity sensor. Gadolinium aluminate was synthesized by the sol-gel self-combustion method. This method allowed us to obtain a highly porous structure in which open pores prevail, a structure favorable to humidity sensors. Most of the materials studied as capacitive/resistive humidity sensors have significant sensitivities only with respect to one of these types of sensors. In the case of the studied gadolinium aluminate with p-type electric conductivity, the relative humidity of the air has a significant influence on both capacitive and resistive types of electric humidity sensors. The capacity increases about 10,000 times, and the resistance decreases about 8000 times as the relative humidity increases from 0 to 98%. The investigated gadolinium aluminate can be used successfully to obtain high-sensitivity capacitive and/or resistive humidity sensors.

The electrical and optical properties stability of poly(3-hexylthiophene) (P3HT) thin films sensitized with nitromethane ferric chloride (FeCl₃) solution was investigated. The optical properties modifications were studied by spectrophotometry and ellipsometry. For electrical characterizations, electrical resistivity measurements were performed. In agreement with the observations of other authors, an important decrease in the electrical resistivity by six orders of magnitude was noticed. In addition, the repeatability and stability of this phenomenon were investigated over a few weeks after sensitization and during different cycles of heating and cooling, both in the dark and under illumination.

The paper shows the obtaining of nanocrystalline iron manganite (FeMnO₃) powders and their investigation in terms of catalytic properties for a series of volatile organic compounds. The catalyst properties were tested in the catalytic combustion of air-diluted vapors of ethanol, methanol, toluene and xylene at moderate temperatures (50–550 °C). Catalytic combustion of the alcohols starts at temperatures between 180 °C and 230 °C. In the case of ethanol vapors, the conversion starts at 230 °C and increases rapidly reaching a value of around 97% at 300 °C. For temperatures higher than 300 °C, the degree of conversion is kept at the same value. In the case of methanol vapors, the conversion starts at a slightly lower temperature (180 °C), and the degree of conversion reaches the value of 97% at a higher temperature (440 °C) than in the case of ethanol, and it also remains constant as the temperature increases. Catalytic combustion of the hydrocarbons starts at lower temperatures (around 50 °C), the degree of conversion is generally lower, and it increases proportionally with the temperature, with the exception of toluene, which shows an intermediate behavior, reaching values of over 97% at 430 °C. The studied iron manganite can be recommended to achieve catalysts that operate at moderate temperatures for the combustion of some alcohols and, especially, ethanol. The performance of this catalyst with regard to ethanol is close to that of a catalyst that uses noble metals in its composition.

In this paper, we report on the effect of titanium dioxide (TiO₂) target sintering temperature on the morphological and optical properties of amorphous titanium dioxide thin films synthesized by pulsed laser deposition (PLD) on indium tin oxide (ITO) glass substrate and subsequently heat-treated in air at low temperature (150 °C). Three types of targets were used, unsintered (pressed at room temperature), sintered at 500 °C and sintered at 1000 °C. The surface morphology of the samples was investigated by scanning electron microscopy (SEM), and profilometry was used for thickness measurements. The structural properties of the films were examined by X-ray diffraction (XRD), while their optical properties were studied by UV‒vis spectroscopy. The obtained TiO₂ thin films have an amorphous nature, as shown by XRD analysis. Profilometer showed that sintered target samples have more reliable thicknesses than unsintered ones. The SEM studies revealed the sufficient structural homogeneity of sintered target nanosized TiO₂ films and agglomerates in the case of unsintered target film. The UV‒vis transmittance spectra showed high transparency in the visible range of PLD films, proportional to the target sintering temperature. The optical band gaps of the films deposited using the 500 °C and 1000 °C sintered targets are closer to those of anatase and rutile phases, respectively, which provides a promising approach to the challenges of amorphous TiO₂-based nanostructures.

Porous nanocrystalline lanthanum perovskite La-Fe-O (LaFeO₃) powders were synthesized by the sol–gel self-combustion method, using polyvinyl alcohol as the colloidal medium. The perovskite structure of the material, without secondary phases, was obtained at a calcination temperature of 900 °C for 40 min. The obtained powder was tested for catalytic activity at moderate temperatures (50–550 °C) for ethanol, methanol, acetone, benzene, and Pb-free gasoline vapors. Catalytic combustion begins at quite low temperatures (60–200 °C), compared to normal combustion, and this can be attributed to the nanometric crystallites, the large specific surface area, and the presence of iron cations with different valences, Fe³⁺/Fe²⁺, resulting from the method we used to obtain the material. The degree of conversion reaches values of over 99% for acetone and ethanol vapors at a temperature of 270 °C and 310 °C, respectively, and over 97% for methanol vapors at a temperature of 330 °C. The degree of conversion for Pb-free gasoline and benzene reaches somewhat lower values, over 88% at much higher temperatures, 470 °C and 550 °C, respectively. The lanthanum perovskite catalyst, LaFeO₃, obtained by the presented preparation method, can be recommended for the combustion of acetone, ethanol, and methanol vapors. The performance of this catalyst is remarkable and can be compared to that of a catalyst containing noble metals in its composition.