Search

This study examines the optimal parameters for obtaining fluorine-doped SnO2 (FTO) films with promising potential for photovoltaic applications. Due to its properties, tin oxide is used in a wide range of technologies, among which the manufacture of solar cells is one of the most important. Being doped with fluorine, tin dioxide becomes a good transparent and conductive electrode, suitable for solar cell applications. The chemical stability and low cost of the doped SnO2 makes it an advantageous alternative to tin-doped indium oxide (ITO). Among the most important characteristics of FTO thin films are high photoconductivity under sunlight irradiation and strong UV absorption. The SnO2 compound, doped with fluorine, exhibits a considerable chemical and physical stability, good electrical conductivity and high transmission (over 85%) in the visible range. The spray pyrolysis technique is the most preferable and efficient deposition method of fluorine-doped SnO2 thin films. This work aims to identify the optimal parameters for the spray pyrolysis of SnO2:F films and to analyze the morphology, transparency and strength of as obtained films in relation to the doping amount in the precursor solution, spraying distance and film thickness. [ABSTRACT FROM AUTHOR]

A study of optical absorption in the region of fundamental absorption edge and photoluminescence at 78 and 293 K of p-GaSe crystals doped with Te is presented. At low concentrations, Te atoms liquidated structural defects in GaSe single crystals and modified their excitonic absorption and photoluminescence.

The influence of Sc3+ ion content on the microstructure, electrical, and gas-sensing properties of Ni0.5Co0.5ScxFe2–xO4 (x = 0.0, 0.05, 0.1 and 0.2) ferrites synthesized by a novel self-combustion method using polyvinyl alcohol as the colloidal medium, was studied. X-ray diffraction, X-ray photon spectroscopy (XPS), Brunauer–Emmett–Teller (BET) surface area, scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX) were employed to characterize the structure and morphology properties of these ferrites. The gas-sensing properties of hydrogen, methane, ethanol, methylene chloride, and benzene were investigated. The samples show p-type semiconducting properties for the studied gases within the temperature range of 100–380 °C. The results revealed that the partial substitution of Fe3+ by Sc3+ ions on the octahedral sites of the spinel structure of Ni0.5Co0.5Fe2O4 ferrite has a favorable effect on the sensing activity of this ferrite. The increase of the degree of Fe3+ ion substitution by Sc3+ ions up to x = 0.2 in the basic composition (Ni0.5Co0.5Fe2O4) results in the increase of the response and the decrease of the optimal operating temperature for all the studied gases. The sensor element Ni0.5Co0.5Sc0.2Fe1.8O4 (x = 0.2) has the best response to benzene (2.57) and to methylene chloride (2.10) at the operating temperature of 175 °C for a gas concentration of 500 ppm and a relative humidity of 50%. Highlights: The Ni0.5Co0.5ScxFe2–xO4 (0 < x < 0.2) ferrites have been prepared by self-combustion method. The porosity is amplified by a system with open pores distributed along the grain agglomerations. The increase of substitution by Sc results in the increase of sensor response to the studied gases. The substitution with Sc ions has the effect of decreasing the optimal operating temperature. The Ni0.5Co0.5Sc0.2Fe1.8O4 sensors have the best response to benzene and methylene chloride gas. [ABSTRACT FROM AUTHOR]