RESUMO
This study explores the controlled laser ablation and corresponding properties of silicon nanoparticles (Si NP) with potential applications in ultraviolet (UV) light sensing. The size distribution of Si NPs was manipulated by adjusting the laser scanning speed during laser ablation of a silicon target in a styrene solution. Characterization techniques, including transmission electron microscopy, Raman spectroscopy, and photoluminescence analysis, were employed to investigate the Si NP structural and photophysical properties. Si NP produced at a laser scanning speed of 3000 mm/s exhibited an average diameter of ~4 nm, polydispersity index of 0.811, and a hypsochromic shift in the Raman spectrum peak position. Under photoexcitation at 365 nm, these Si NPs emitted apparent white light, demonstrating their potential for optoelectronic applications. Photoluminescence analysis revealed biexponential decay behavior, suggesting multiple radiative recombination pathways within the nanoscale structure. Furthermore, a thin film containing Si NP was utilized as a passive filter for a 2nd generation CCD detector, expanding the functionality of the non-UV-sensitive detectors in optics, spectrometry, and sensor technologies.
RESUMO
As the industry develops and energy demand increases, wind turbines are increasingly being used to generate electricity, resulting in an increasing number of obsolete turbine blades that need to be properly recycled or used as a secondary raw material in other industries. The authors of this work propose an innovative technology not yet studied in the literature, where the wind turbine blades are mechanically shredded and micrometric fibers are formed from the obtained powder using plasma technologies. As shown by SEM and EDS studies, the powder is composed of irregularly shaped microgranules and the carbon content in the obtained fiber is lower by up to seven times compared with the original powder. Meanwhile, the chromatographic studies show that no hazardous to the environment gases are formed during the fiber production. It is worth mentioning that this fiber formation technology can be one of the additional methods for recycling wind turbine blades, and the obtained fiber can be used as a secondary raw material in the production of catalysts, construction materials, etc.
RESUMO
Herein, photothermal modification of nanocomposite films consisting of hydrated vanadium pentoxide (V2O5·nH2O) nanoribbons wrapped with graphene oxide (GO) flakes was performed via 405 nm direct laser irradiation. The combination of X-ray diffraction, X-ray photoelectron spectroscopy, Raman scattering, transmission electron microscopy, and scanning electron microscopy allowed comprehensive characterization of physical and chemical changes of GO/V2O5·nH2O nanocomposite films upon photothermal modification. The modified nanocomposite films exhibited porous surface morphology (17.27 m2 g-1) consisting of randomly distributed pillarlike protrusions. The photothermal modification process of GO/V2O5·nH2O enhanced the electrical conductivity of nanocomposite from 1.6 to 6.8 S/m. It was also determined that the direct laser irradiation of GO/V2O5·nH2O resulted in considerable decrease of C-O bounds as well as O-H functional groups with an increase of the laser power density.
