Probing the spectrally selective property of NbB2-based tandem absorber coating for concentrated solar power application

Poobalan, RK and Singh, MP and Basu, B (2021) Probing the spectrally selective property of NbB2-based tandem absorber coating for concentrated solar power application. In: Journal of the American Ceramic Society, 105 (2). pp. 1136-1148.

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Abstract

Solar selective coating with good thermal stability is the primary requirement for a concentrated solar power (CSP) plant to function with better photothermal efficiency. In recent years, ultra-high-temperature ceramic-based coatings have been explored as potential materials for solar selective coatings. In this context, NbB2/Nb(BN)/Al2O3 tandem absorber coating was designed to be fabricated on a stainless-steel substrate by the radio frequency magnetron sputtering of spark plasma sintered ceramic target. In the bulk form, the NbB2 ceramic exhibits high solar absorptance (α = 0.756) and thermal emissivity (ε = 0.43), whereas the amorphous single NbB2 coating exhibits α/ε = 0.716/0.13. Reactive sputtering of NbB2 in nitrogen produced a semi-transparent coating with an optical bandgap of ∼2.80 eV and was used as the secondary absorber layer. Raman and X-ray photoelectron spectroscopy analyses reveal mild oxygen incorporation in the absorber layers. The developed SS/NbB2/Nb(BNO)/Al2O3 tandem absorber exhibits a good solar absorptance of 0.950 and a moderate thermal emissivity of 0.15 at room temperature. The coatings exhibited good thermal stability when heated in vacuum for 5 h up to 700°C, and the selectivity (α/ε) remains above 6. The present work shows the possibility of exploring NbB2-based tandem absorber coatings for CSP applications.

Item Type:	Journal Article
Publication:	Journal of the American Ceramic Society
Publisher:	John Wiley and Sons Inc
Additional Information:	The copyright for this article belongs to the The American Ceramic Society, John Wiley and Sons Inc
Keywords:	Coatings; Electromagnetic wave emission; Niobium; Niobium compounds; Reactive sputtering; Solar absorbers; Solar energy; Thermodynamic stability; X ray photoelectron spectroscopy, Absorber coatings; Concentrated solar power; Multi-layer-coating; Niobium diboride; Power applications; R.F. magnetron sputtering; Solar absorptance; Solar selective coating; Spectral selectivity; Tandem absorber, Magnetron sputtering
Department/Centre:	Division of Chemical Sciences > Materials Research Centre Division of Interdisciplinary Sciences > Interdisciplinary Centre for Energy Research
Date Deposited:	01 Jul 2022 06:14
Last Modified:	01 Jul 2022 06:14
URI:	https://eprints.iisc.ac.in/id/eprint/74034

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