Novel nanocomposite coatings with dispersed organic nanoparticles for solar absorbers

A natural pigment (Anthocyanin extracted from Sambucus nigra L. fruit) was incorporated by dipping sputtered titanium oxide films into a pigment solution. The pigment solution has red colour and an absorption peak located in the wavelength range of 520 to 540 nm. Titanium oxide thin films were prepared by reactive DC magnetron sputtering and reactive pulsing DC magnetron sputtering from a Titanium target in O2 + Ar atmosphere onto glass slides. Pigment incorporation in thin films was found dependent of both morphology and composition, which depends on deposition parameters, like pulsing frequency and oxygen flow rate. The incorporation of this pigment in TiOx thin films increases the final solar absorption and decreases the final average roughness of these films. The effect in solar absorption is higher in films prepared by DC and pulsed DC at pulsing frequency of 200 kHz.