Solar selective absorbers consisting of semiconducting silicide absorbing layers with thermally stabilized Ag base

• Main Authors: Okuhara, Yoshiki, Kuroyama, Tomohiro, Yokoe, Daisaku, Kato, Takeharu, Takata, Masasuke, Tsutsui, Takuhito, Noritake, Kazuto
• Format: Conference Proceeding
• Language: English
• Subjects: Absorbers; Absorptance; Absorptivity; Disilicides; Energy conversion; High temperature; Infrared radiation; Intermetallic compounds; Iron silicide; Laminates; Laminating; Multilayers; Nanoparticles; Photovoltaic cells; Refractivity; Semiconductor materials; Silicon dioxide; Solar radiation; Spectra; Temperature dependence; Thermal energy
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5117631

Solar selective absorber coatings consisting of semiconducting β-FeSi2 and thermally-stabilized Ag base have been fabricated for high temperature thermal energy conversion below 650 °C. The band gap of the β-FeSi2 around 0.8 eV was suitable for absorbing solar radiation, and the high refractive index was gradually declined to the top surface by composing with SiO2. The Ag base for suppressing infrared radiation loss was thermally stabilized by adding SiNx nanoparticles and laminating with W layers. In-situ high temperature measurements of optical constants (refractive index n and extinction coefficient k) for each composing layer were carried out, and the temperature dependence of absorptance spectra for the multilayers were simulated based on the n and k spectra. The derived absorptance spectra showed that the developed multilayers achieved highly efficient solar-thermal energy conversion of above 78% below 650 °C.