0000000000205529
AUTHOR
G. Raimondi
Trade-off Performance of Optical Nanoantennas for Solar Energy Harvesting Applications
In this paper, the optimum behaviour of optical nanoantennas, in terms of impedance, directivity, available power, and field enhancement, at a resonance frequency of about 350 THz, will be shown. Optimum configurations are obtained by varying nanoantennas geometry in order to maximize the available power, enhancing the electric field in gap proximity and so the absorptivity. Moreover, the simulation results for aluminum nanoantennas on a three-layers substrate, will be reported, and a trade-off performance comparison among different antennas will be discussed. This study can guide both the engineering and the fabrication of plasmonic nanoantennas.
Electronic modifications in (Ba,La)(Fe,Zn,Y)O3−δ unveiled by oxygen K-edge X-ray Raman scattering
Oxides with mixed protonic-electronic conductivity are relevant as oxygen electrodes for protonic ceramic fuel cells and electrolyzers. We investigate the modification of the electronic structure of (Ba,La)(Fe,Zn,Y)O3−δ when iron is partially replaced by Zn2+ or Y3+ and when it changes between 3+ and 4+ formal oxidation states. With a combination of X-ray Raman scattering (O K-edge) and X-ray absorption near edge structure (Fe, Zn, and Y K-edges) and the corresponding simulations reproducing the spectroscopic data, we quantitatively analyze the degree of covalency of the Fe-O bonds in reduced (Fe mainly 3+) and oxidized (Fe mainly 4+) materials. The simulations employ two semi-empirical par…