Structural and optical properties of Pt-Al2O3 double cermet as selective solar absorber

A new Pt-Al2O3 double cermet selective solar absorber configuration was prepared using magnetron sputtering system at room temperature. The Scanning Electron Microscopy (SEM) investigations showed that the surface of the Pt-Al2O3 double cermet coating was characterized by a granular structure, while AFM and cross-section SEM analysis revealed a columnar structure with an average height of 45.4 +/- 0.1 nm and a surface roughness of 21.1 nm. EDS analysis confirmed the chemical purity of the without any detectable impurities. The coatings showed a combination of a high selective solar absorptance of 0.97 and a thermal emittance of 0.18 at 400 degrees C, which is better than almost all Al2O3, based selective solar absorbers reported so far. An optical analysis revealed that these favorable properties arise from a combination of interference, and light trapping/absorption effects that occur in the multilayered columnar solar absorber coating. The Pt-Al2O3 cermet showed an excellent photo-thermal conversion efficiency of 88%. (C) 2019 Elsevier Ltd. All rights reserved.

Automated summary

A new Pt-Al2O3 double cermet selective solar absorber configuration was prepared using magnetron sputtering system at room temperature. The coatings showed a high selective solar absorptance of 0.97 and a thermal emittance of 0.18 at 400 degrees C, which is better than almost all Al2O3 based selective solar absorbers reported so far. Optical analysis revealed that these properties arise from interference and light trapping/absorption effects in the multilayered columnar solar absorber coating. The Pt-Al2O3 cermet also exhibited an excellent photo-thermal conversion efficiency of 88%.