This paper discusses the effect of adding reduced erbium-doped ceria nanoparticles (REDC NPs) as a coating on silicon solar cells. Reduced ceria nanoparticles doped with erbium have the advantages of both improving conductivity and optical conversion of solar cells. Oxygen vacancies in ceria nanoparticles reduce Ce4+ to Ce3+ which follow the rule of improving conductivity of solar cells through the hopping mechanism. The existence of Ce3+ helps in the down-conversion from 430 nm excitation to 530 nm emission. The erbium dopant forms energy levels inside the low-phonon ceria host to up-convert the 780 nm excitations into green and red emissions. When coating reduced erbium-doped ceria nanoparticles on the back side of a solar cell, a promising improvement in the solar cell efficiency has been observed from 15% to 16.5% due to the mutual impact of improved electric conductivity and multi-optical conversions. Finally, the impact of the added coater on the electric field distribution inside the solar cell has been studied.

This work presents a new nanocomposite of cerium oxide (ceria) nanoparticles embedded in electrospun PVA nanofibers for optical sensing of radicals in solutions. Our ceria nanoparticles are synthesized to have O-vacancies which are the receptors for the radicals extracted from peroxide in water solution. Ceria nanoparticles are embedded insitu in PVA solution and then formed as nanofibers using an electrospinning technique. The formed nanocomposite emits visible fluorescent emissions under 430 nm excitation, due to the active ceria nanoparticles with fluorescent Ce3+ ionization states. When the formed nanocomposite is in contact with peroxide solution, the fluorescence emission intensity peak has been found to be reduced with increasing concentration of peroxide or the corresponding radicals through a fluorescence quenching mechanism. The fluorescence intensity peak is found to be reduced to more than 30% of its original value at a peroxide weight concentration up to 27%. This work could be helpful in further applications of radicals sensing using a solid mat through biomedical and environmental monitoring applications.

No abstract

This paper introduces a new fluorescent nanocomposite of electrospun biodegradable nanofibers embedded with optical nanoparticles. In detail, this work introduces the fluorescence properties of PVA nanofibers generated by the electrospinning technique with embedded cerium oxide (ceria) nanoparticles. Under near-ultra violet excitation, the synthesized nanocomposite generates a visible fluorescent emission at 520 nm, varying its intensity peak according to the concentration of in situ embedded ceria nanoparticles. This is due to the fact that the embedded ceria nanoparticles have optical tri-valiant cerium ions, associated with formed oxygen vacancies, with a direct allowed bandgap around 3.5 eV. In addition, the impact of chemical crosslinking of the PVA on the fluorescence emission is studied in both cases of adding ceria nanoparticles in situ or of a post-synthesis addition via a spin-coating mechanism. Other optical and structural characteristics such as absorbance dispersion, direct bandgap, FTIR spectroscopy, and SEM analysis are presented. The synthesized optical nanocomposite could be helpful in different applications such as environmental monitoring and bioimaging.

This aim of the percent work is to develop new, cost effective, high performance, lightweight polymer matrix composite nanofiber for corrosion resistance of aluminum in 0.1 M hydrochloric acid (0.1 M HCl) solution. Cerium oxide nanoparticles (ceria NPs) are embedded in-situ in poly vinyl chloride (PVC) solution, and then formed as nanofibers using electrospinning technique. The formed nanocomposite coating of PVC is successfully deposited on aluminum substrates; considering these substrates as metallic target in the electrospinning procedure. Measurements of corrosion for aluminum substrate before, and after coating with polymer nanofiber in 0.1 M HCl solution is performed using potentiodynamic polarization ,and electrochemical impedance spectroscopy techniques. Potentiodynamic polarization and electrochemical impedance results confirm that ceria NPS embedded in-situ within PVC NFS coatings protect the aluminum surface from being corroded through minimizing both of its corrosion rate, corrosion current and increasing the surfaces' polarization resistance. The morphologies of polymer nanofiber coatings are imaged using scanning electron microscopy (SEM), with detecting the optical characteristics of the synthesized nanocomposite to prove the existence of oxygen vacancies associated to tri-valent cerium ions via optical analysis such as direct band gap, and fluorescence measurements. These vacancies are considered physical adsorbers for radicals which consequently reduces the corrosion rate. Average mean diameter of ceria NPS was measured using transmission electron microscopy (TEM).