Linking Optical Properties and Nanostructure of NiCrOx Cermet Nanocomposite for Solar Thermal Application

Abstract

Conversion of solar energy into thermal energy helps reducing consumption of non-renewable energies. Cermets (ceramic-metal composites) are versatile materials suitable, amongst other applications, for solar selective absorbers. The presence of metallic Ni nanoparticles (NPs) in the dielectric matrix is a prerequisite for efficient solar selective absorption in NiCrOx cermets (Zhao and Wackelgard, Solar Energy Mater Solar Cells 90:1861–1874, 2006). By combining comprehensive chemical and structural analyses, but also electronic microscopy, we revealed the origin of the remarkable optical properties of this cermet material. A solar absorber multilayer stack on aluminium substrate using a sputtered NiCrOx layers allows us to achieve solar absorptance as high as α = 96. 1 % while keeping thermal emissivity as low as ε = 2. 2 % both values are comparable to best values recorded so far (Buhrman, Physics of solar selective surfaces. In: Ber (ed) Advances in solar energy. Springer, New York, pp 207–282, 1986). Determining the origin of sputtered NiCrOx cermets optical properties drives further optimization of solar absorbers.

FormalPara Abstract

Conversion of solar energy into thermal energy helps reducing consumption of non-renewable energies. Cermets (ceramic-metal composites) are versatile materials suitable, amongst other applications, for solar selective absorbers. The presence of metallic Ni nanoparticles (NPs) in the dielectric matrix is a prerequisite for efficient solar selective absorption in NiCrOx cermets (Zhao and Wackelgard, Solar Energy Mater Solar Cells 90:1861–1874, 2006). By combining comprehensive chemical and structural analyses, but also electronic microscopy, we revealed the origin of the remarkable optical properties of this cermet material. A solar absorber multilayer stack on aluminium substrate using a sputtered NiCrOx layers allows us to achieve solar absorptance as high as α = 96. 1 % while keeping thermal emissivity as low as ε = 2. 2 % both values are comparable to best values recorded so far (Buhrman, Physics of solar selective surfaces. In: Ber (ed) Advances in solar energy. Springer, New York, pp 207–282, 1986). Determining the origin of sputtered NiCrOx cermets optical properties drives further optimization of solar absorbers.