Copper–manganese oxide (CuMnOx) thin films
are proposed as efficient and thermally stable selective
solar absorbers. The coatings were deposited on aluminum,
stainless steel, and glass substrates by dip-coating method
from the alcoholic solution of the Cu and Mn nitrate. An
organic filmogen was introduced in order to get better
adherence with the substrate hence to get uniform films
even for larger substrates. The coated films were dried and
subsequently heat-treated at 500 C. X-ray diffraction
spectra of the annealed film showed the formation of pure
Cu–Mn oxide spinel structure (Cu1.5Mn1.5O4) in the film.
FTIR spectra show complete removal of the organic species
after thermal treatment at 500 C. The solar absorptance
and thermal emittance were calculated from the
hemispherical reflectance spectra in the UV/Vis/NIR and
IR range, respectively. The maximum visible absorptance
with minimizing the infrared thermal emittance was optimized
by controlling the thickness of the films, choosing
substrates, and introducing a SiO2 overlayer
