High-temperature solar-selective coatings based on Cr(Al)N. Part 2: Design, spectral properties and thermal stability of multilayer stacks

• Published in: Solar energy materials and solar cells 2020-12, Vol.218, p.110812, Article 110812
• Main Authors: Rojas, T.C., Caro, A., Escobar-Galindo, R., Sánchez-López, J.C.
• Format: Article
• Language: English
• Subjects: Absorbers; Absorptance; Absorptivity; Aluminum oxide; Austenitic stainless steels; Chromium nitride; Coatings; CrAlN-based films; Direct current; Emittance; Energy conversion; Energy conversion efficiency; Heat treatment; High temperature; Magnetron sputtering; Multilayers; Optical properties; Optical simulation; Oxidation; Photovoltaic cells; Selectivity; Solar absorptance; Solar energy; Solar selective absorber; Stacks; Structural analysis; Thermal emittance; Thermal stability; Thickness
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2020.110812

Two multilayer solar selective absorber coatings [Al/CrN0.95/Cr0.96Al0.04N1.08/Cr0.53Al0.47N1.12/Al2O3 (stack #1) and Cr0.96Al0.04N0.89/Cr0.62Al0.38N1.00/Cr0.53Al0.47N1.12/Al2O3 (stack #2)] were deposited on 316L steel by combining direct current (DC) and high power impulse magnetron sputtering (HiPIMS) technologies with the aim of increasing the working limit temperature. The composition and thickness of the constituent layers were optimized using CODE software to achieve a high solar absorptance (α) and low values of thermal emittance (ε) in the infrared region. The deposited multilayered stacks were heated during 2 h in air at 600, 700 and 800 °C to study their thermal stability and optical performance. Compositional, structural and optical characterization of the stacks (as-prepared and after thermal treatment) was performed. Both stacks presented a good solar selectivity with α > 95% and ε