Cr/alpha-Cr2O3 monodispersed spherical core-shell particles based solar absorbers

Abstract

Monodispersed spherical core-shell particles of Cr/alpha-Cr2O3 cermet ACG coatings investigated within this contribution could be successfully employed in thermal converters. Their selectivity depends on their chemical, physical and structural characteristics and related optical properties like reflectance, emittance, solar light absorption, or absorptance and transmittance. Parameters such as particles size, aging-time and substrate roughening will greatly influence their relevant optical properties as reported. The coated Cr/alpha-Cr2O3 spherical particles on rough copper substrates by a simple self-assembly-like method were characterized by scanning electron microscopy, energy dispersive spectrometry, Raman spectroscopy, and diffuse reflectance UV-VIS-NIR spectroscopy. The samples aged for more than 40h at 75 degrees C exhibit the targeted high absorbing optical characteristic “Black chrome” while those aged for smaller or equal to 40h show a significant high diffuse reflectance.