Thin films of silica–carbon nanocomposites for selective solar absorbers

In this paper, we describe new film structures based on porous silica and nanosized carbon for selective solar absorbers application. The films show high absorbance in the solar-spectral region and low emittance in the IR region. The best results for 1000 nm thick films of nanocomposite silica–carbon has excellent optical parameters, absorbance as = 0.94 and IR emissivity of e = 0.15. The films show good stability under the influence of humidity and high temperatures (250–300 8C). This new solar absorber structure offers low cost production and both the materials are easily available and non-toxic. The overall process of film preparation is simple and works under ‘‘green-chemistry’’ conditions.