Black Cr/α-Cr2O3 nanoparticles based solar absorbers

Monodisperse spherical core-shell particles of Cr/alpha-Cr2O3 with high adhesion were successfully coated on rough copper substrates by a simple self-assembly-like method for the use in solar thermal absorbers. The structure and morphology of the core-shell particles of Cr/alpha-Cr2O3 were effectively controlled by deposition temperature and the pH of the initial precursor solution. Their characterizations were carried out with X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry and attenuated total reflection, as well as UV-vis diffuse reflectance spectroscopy. The samples aged for more than 40 h at 75 degrees C exhibit the targeted high absorbing optical characteristic Black chrome while those aged for <= 40 h show a significant high UV-vis diffuse reflectance green color. (C) 2011 Elsevier B.V. All rights reserved.