title: Lanthanum hexaboride for solar energy applications.
abstract: We investigate the optical properties of LaB6- based materials, as possible candidates for solid absorbers in Concentrating Solar Power (CSP) systems. Bulk LaB6materials were thermally consolidated by hot pressing starting from commercial powders. To assess the solar absorbance and spectral selectivity properties, room-temperature hemispherical reflectance spectra were measured from the ultraviolet to the mid-infrared, considering different compositions, porosities and surface roughnesses. Thermal emittance at around 1100 K has been measured. Experimental results showed that LaB6can have a solar absorbance comparable to that of the most advanced solar absorber material in actual plants such as Silicon Carbide, with a higher spectral selectivity. Moreover, LaB6has also the appealing characteristics to be a thermionic material, so that it could act at the same time both as direct high-temperature solar absorber and as electron source, significantly reducing system complexity in future concentrating solar thermionic systems and bringing a real innovation in this field.
authors.affiliation: CNR-INO National Institute of Optics, Largo E. Fermi, 6, I-50125, Firenze, Italy. elisa.sani@ino.it.
authors.forename: Elisa
authors.identifier: http://orcid.org/0000-0001-9854-2892
authors.initials: E
authors.lastname: Sani
authors.affiliation: CNR-INO National Institute of Optics, Largo E. Fermi, 6, I-50125, Firenze, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Mercatelli
authors.affiliation: CNR-INO National Institute of Optics, Largo E. Fermi, 6, I-50125, Firenze, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Meucci
authors.affiliation: CNR-ISTEC, Institute of Science and Technology for Ceramics, Via Granarolo 64, I-48018, Faenza, Italy.
authors.forename: Luca
authors.identifier: http://orcid.org/0000-0002-6208-2035
authors.initials: L
authors.lastname: Zoli
authors.affiliation: CNR-ISTEC, Institute of Science and Technology for Ceramics, Via Granarolo 64, I-48018, Faenza, Italy.
authors.forename: Diletta
authors.initials: D
authors.lastname: Sciti