In this study, cupric oxide (CuO) nanoparticles were synthesized via sonochemical method. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. The spherical CuO nanoparticles were dispersed in sodium hexametaphosphate under sonication (25 kHz) to analyze the particle size distribution and UV absorption spectra. Using these absorption spectra, we further examined the CuO nanoparticle to explore the possibility of using them as a material for applications such as solar cell and textile production.

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The current scenario illustrates distinct interest in developing renewable energy sources for power generation. In this regard, several researches are performed in enhancing the power conversion efficiency of solar cells. The present work focuses on utilizing ZnAl 2 O 4 (gahnite) spinel as antireflection coating material to improve the power conversion efficiency of silicon solar cells. Gahnite was synthesized using two precursors namely zinc nitrate hexahydrate and aluminum nitrate nonahydrate through sol-gel technique. The thickness of the prepared gahnite sheets measured through atomic force microscopy was around 50 nm. Single to quintuple layers of gahnite was deposited on silicon solar substrate using spin coating technique. The influence of gahnite coating on the structural, optical, electrical properties and cell temperature of silicon solar cells are analyzed. The synthesized gahnite bears spinel crystal structure in the form of two dimensional nanosheet. Increment in layer thickness proves the deposition of single to quintuple layer on silicon substrate. A maximum of 93% transmittance and 20.72% power conversion efficiency at a low cell temperature (39.4 °C) has been achieved for triple layer deposition proving diffusion of more photons on the substrate. The obtained results prove gahnite as suitable anti-reflection coating material for enhancing the power conversion efficiency of silicon solar cells.

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Purpose This paper aims to overcome the corrosion in AA7075 by incorporating the dual-reinforcements like Al2O3 and SiC through friction stir processing (FSP). In recent days, an automotive monocoque structure undergoes corrosion because of changes in environmental conditions. Design/methodology/approach Surface hybrid composites (SHCs) of AA7075 with different weight ratios of Al2O3 and SiC were fabricated at a rotating speed of 1000 rpm, traveling speed of 56 mm/min and tool tilt angle of 2º with two passes. Surface regions were observed using optical microscopy, and the potentiodynamic corrosion test was performed under a 3.5 per cent NaCl environment at room temperature. Then, the surface morphology analysis of corroded samples and their structural properties were also investigated through scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron dispersive spectroscopy (EDS). Findings Through FSP, an improved interface between the reinforced particles and the AA7075 base matrix was observed because of the severe plastic deformation. Potentiodynamic polarization tests confirmed that the AA7075 matrix with a higher concentration of Al2O3 and a lower concentration of SiC (Al2O3 – 75 per cent and SiC – 25 per cent) possesses a lower corrosion rate than other specimens. This result is because of the combined effect of stable passive film formation and the resistance produced by hard SiC particles. In addition, the formation of a stronger interface between the reinforcements and the base matrix impedes the NaCl solution attack. The SEM micrograph depicts the film crystallinity variations with an increase in Al2O3 content. Debonding between the layers was observed on increasing the SiC content in the base matrix. XRD shows the peaks of reinforcing elements that influence the corrosion behavior. These observations suggest that the AA7075 reinforced with a higher concentration of Al2O3 and a lower concentration of SiC through FSP affords a suitable solution for automotive monocoque applications. Originality/value The corrosion rate has been identified for AA7075 SHCs with various concentrations of Al2O3 and SiC and has been compared with that of the base metal and the friction stir processed specimen without reinforcement.