In this work, (Cu1-xAgx)2ZnSnSe4 (CAZTSe) alloys with various silver content (x= 0.0, 0.1and 0.2) have been prepared by reacting their high purity elements (Cu, Ag, Zn, Sn and Se) in an evacuated quartz tube under pressure of 10 -3Torr. The composition of the prepared alloys was determined by energy dispersive X-ray spectroscopy (EDXS) analysis, the results were close to the theoretical values. CAZTSe thin films with a thickness of 800 nm were deposited by thermal evaporation technique on glass substrates at room temperature (RT) with a deposition rate of 0.53nm/sec. Similarly, CdS thin films were deposited with a thickness of 100 nm on the same substrates at RT with a deposition rate of 0.3nm/sec from ready-made CdS alloy powder. All prepared thin films were annealed at temperatures of 373K and 473K under vacuum (10-3Torr) for 1h. X-ray analysis showed that all CAZTSe alloys and their thin films were polycrystalline and have the tetragonal structure with preferential orientation in the (112) direction, while all thin CdS films were polycrystalline and have the hexagonal structure with preferential orientation in the (002) direction. The scanning electron microscopy (SEM) technique was used to study the surface morphology of all prepared CAZTSe films, while the atomic force microscopy (AFM) technique was used to study the surface topography of all prepared CAZTSe and CdS films. SEM results revealed that CAZTSe films had uniform surface features with irregular sized grains, while AFM results showed that the surface roughness and the average grain size of CAZTSe and CdS thin films increased with increasing Ag content for CAZTSe thin films and annealing temperature for CAZTSe and CdS thin films. The absorbance and transmittance spectra for CAZTSe and CdS thin films were recorded in the wavelength ranges of (400-1100) nm and (350- 1100) nm, respectively. Optical measurements showed that all CAZTSe and CdS thin films have a direct energy gap (Eg) that decreased with increasing silver content for CAZTSe thin films and annealing temperature (Ta) for both types of prepared thin films, so it decreased from 1.73 eV to1.5 eV when x content increased from 0.0 to 0.2 and decreased from 1.5 eV to1.46 eV and from 2.47 eV to 2.38 eV when Ta increased from RT to 473K for CAZTSe thin films with x content equal to 0.2 and CdS thin films, respectively. Optical constants such as extinction coefficient, refractive index and dielectric constant were calculated for all prepared thin films. The measurements of the electrical properties for prepared films showed that the D.C electrical conductivity (σd.c) increased with increasing Ag content for CAZTSe thin films and annealing temperature for both types of thin films. So the electrical conductivity changed from 1.1276*10-2 (Ω.cm)-1 to 28.9266*10-2 (Ω.cm)-1 when x changed from 0.0 to 0.2 and changed from 28.9266*10-2 (Ω.cm)-1 to 57.4599*10-2 (Ω.cm)-1 and from 4.0476*10-4 (Ω.cm)-1 to 9.4227*10-4 (Ω.cm)-1 when Ta changed from RT to 473K for CAZTSe thin films with Ag content equal to 0.2 and CdS thin films, respectively. The prepared thin films have two activation energies (Ea1 & Ea2) in the temperature ranges of (318-488)K and (313-443)K for CAZTSe and CdS films, respectively. The results of Hall effect for CAZTSe thin films showed that all films were of acceptor type and the concentration of holes in them decreased with increasing silver content and annealing temperature, while CdS thin films were of donor type and the concentration of electrons in them increased with increasing annealing temperature. In this research, solar cells were fabricated from CdS/CAZTSe/Si structurThe C-V measurements revealed that all prepared heterojunctions were of the abrupt type and the junction capacitance and carrier concentration reduced while the width of depletion region and the built-in potential increased with increasing the silver content and annealing temperature. The current-voltage characteristics under dark condition of CAZTSe heterojunctions showed that both the ideality factor and saturation current decreased with increasing Ag content and annealing temperature. While,The current-voltage characteristics under dark condition of CAZTSe heterojunctions showed that both the ideality factor and saturation current decreased with increasing Ag content and annealing temperature. While, the current-voltage measurements under illumination showed that the performance of heterojunction solar cell improved with increasing Ag content and annealing temperature. The result indicated that the prepared solar cell with 0.2 Ag content and 473K annealing temperature exhibited the highest efficiency (η = 2.827%) compared to other prepared solar cells
The organic compound imidazole has the chemical formula C3N2H4. Numerous significant biological compounds contain imidazole. The amino acid histidine is the most prevalent. The substituted imidazole derivatives have great potential for treating a variety of systemic fungi infections. Thiourea is an organosulfur compound with the formula SC(NH2)2. It is a reagent in organic synthesis. In this paper, some new imidazole and thiourea derivatives are synthesized, characterized, and studied for their biological activity. These new compounds were synthesized from the starting material terephthalic acid, which was transformed to corresponding ester [I] by the refluxing of diacid with methanol in the presence of H2SO4 as a catalyst, compound [I] con
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This paper presents an experimental study of cooling photovoltaic (PV) panels using evaporative cooling. Underground (geothermal energy) water used to extract heat from it during cooling and cleaning of PV panels. An experimental test rig was constructed and tested under hot and dusty climate conditions in Baghdad. An active cooling system was used with auxiliary an underground water tank to provide cold water as a coolant over both PV surfaces to reduce its temperature. The cellulose pad has been arranged on the back surface and sprays cooling on the front side. Two identical PV panels modules used: without cooling and evaporative water cooling. The experiments are comprised of four cases: Case (I): backside cooling, Ca
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New substituted coumarins derivatives were synthesized by using nitration reaction to produce different nitro coumarin isomers which were separated from these isomers by using different solvent, and the reduction of nitro compounds was done to give corresponding amino coumarins. Temperature and reaction time of reaction were very important factors in determining the most productive nitro isotopes. A low temperature for three hours was sufficient to give a high product of a compound 6-nitro coumarin while increasing the temperature for a period of twenty-four hours that gave a high product of 8-nitro-coumarin. The synthesized compounds were confirmed by FT-IR,1 H-NMR, and13 C-NMR spectroscopy and all final compounds were tested for their ant
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Purpose: To assess the antioxidant and antineoplastic effects of Hibiscus sabdariffa Linn. on oral squamous cell carcinoma cells. Materials and Methods: Human squamous cell carcinoma HSCC cells were tested for cytotoxicity by a methanol extract of Hibiscus sabdariffa (MEHSP). After 24, 48, and 72 ...
The structural properties of ternary chalcopyrite AgAlSe2 compound alloys and thin films that prepared by the thermal evaporation method at room temperature on glass substrate with a deposition rate (5±0.1) nm s-1 for different values of thickness (250,500 and 750±20) nm, have been studied, using X-ray diffraction technology. As well as, the optical properties of the prepared films have been investigated. The structural investigated shows that the alloy has polycrystalline structure of tetragonal type with preferential orientation (112), while the films have amorphous structure. Optical measurement shows that AgAlSe2 films have high absorption in the range of wavelength (350-700 nm). The optical energy gap for allowed direct transition we
... Show MoreThe structural properties of ternary chalcopyrite AgAlSe2 compound alloys and thin films that prepared by the thermal evaporation method at room temperature on glass substrate with a deposition rate (5±0.1) nm s-1 for different values of thickness (250,500 and 750±20) nm, have been studied, using X-ray diffraction technology. As well as, the optical properties of the prepared films have been investigated. The structural investigated shows that the alloy has polycrystalline structure of tetragonal type with preferential orientation (112), while the films have amorphous structure. Optical measurement shows that AgAlSe2 films have high absorption in the range of wavelength (350-700 nm). The optical energy gap for allowed direct
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