The design of an efficient and stable solar selective coating for Concentrating Solar Power central receivers requires a
complex study of the materials candidates that compose the coating. Carbon-transition metal nanocomposites were
studied in this work as absorber materials because they show appropriate optical properties with high absorption in the
solar region and low thermal emittance in the infrared. Furthermore metal carbides are thermal and mechanical stable in
air at high temperatures.
In this work a solar selective coating was grown by a dual source filtered cathodic vacuum arc. The complete stack
consists on an infrared reflection layer, an absorber layer of carbon-zirconium carbide nanocomposites and an
antireflection layer. The aim of this research is optimize the absorber layer and for that, the metal content was controlled
by adjusting the pulse ratio between the two arc sources. The elemental composition was determined by Ion Beam
Analysis, X-Ray diffraction measurements show the crystal structure and the optical properties were characterized by
spectroscopic ellipsometry measurements. The reflectance spectra of the complete selective coating were simulated with
the optical software CODE. Bruggeman effective medium approximation was employed to average the dielectric
functions of the two components which constitute the nanocomposite in the absorber layer. The optimized coating
exhibited a solar absorptance of 95.41% and thermal emittance of 3.5% for 400°C. The simulated results were validated
with a deposited multilayer selective coating.
A systematic study of TiO2 films deposited by dc filtered cathodic vacuum arc (FCVA) was carried out by varying the deposition parameters in a reactive oxygen atmosphere. The influence of the oxygen partial pressure on film properties is analyzed. Composition was obtained by Rutherford backscattering spectroscopy (RBS) measurements, which also allow us to obtain the density of the films. Morphology of the samples was studied by scanning electron microscopy (SEM) and their optical properties by ellipsometry. Transparent, very dense and stoichiometric TiO2 films were obtained by FCVA at room temperature.