Broadband optical absorption of amorphous carbon/Ag nanocomposite films and its potential for solar harvesting applications

• Published in: Solar energy materials and solar cells 2013-10, Vol.117, p.350-356
• Main Authors: Zoubos, H., Koutsokeras, L.E., Anagnostopoulos, D.F., Lidorikis, E., Kalogirou, S.A., Wildes, A.R., Kelires, P.C., Patsalas, P.
• Format: Article
• Language: English
• Subjects: Amorphous carbon; Broadband; Carbon; Cross-disciplinary physics: materials science; rheology; Effective medium approximation; Exact sciences and technology; Graphitization; Materials science; Nanocomposites; Nanomaterials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Other topics in nanoscale materials and structures; Physics; Plasmonics; Silver; Solar absorption; Spectral emissivity
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/j.solmat.2013.06.019

The emergence of Localized Surface Plasmon Resonance (LSPR) in nanocomposite films consisting of a hydrogen-free amorphous Carbon (a-C) matrix and Ag is considered theoretically and experimentally. While in theory it could be manifested for highly tetrahedral (>90% sp3) matrices, Auger electron spectroscopy and neutron reflectivity have shown that the incorporation of Ag into the a-C matrix induces severe graphitization that eliminates the LSPR; nonetheless, the dielectric damping of graphitized a-C, in combination with the π−π⁎ electronic transitions of carbon and the defect states introduced by Ag, cumulatively result in a strong broadband optical absorption in the near infrared, visible and UVA/UVB spectral ranges, revealed by optical reflectivity spectra, that coincides with the solar emission spectrum. The incorporation of Ag into a-C at room temperature thus proves to be an energy-efficient pathway for the controlled graphitization and the tailored optical absorption of novel nanocomposite films for solar photothermal applications. •We provide the optical response of amorphous Carbon/Silver nanocomposite layers, whose absorbance is tailored to coincide with the solar emittance.•We identify the mechanism lying behind the atomical dispersion or nanoparticle formation of Ag into amorphous Carbon.•We manufacture a black carbon material at room temperature and without ion damage.