Solar spectral performance of nanopigments

Solar spectral behavior of nanopigments has been an important issue in many practical relevance due to their tunable properties. There are extensive literatures on radiative transfer through pigmented coating but they are generally restricted to a small range of materials with specific properties and particular applications. Current study, on the other hand, concerns with a comprehensive look at contribution of fundamental characteristics of nanopigments on spectral behavior of the pigmented coatings. In order to accomplish this goal, a Discrete Ordinate Method (DOM), known as Multi Flux (MF) model in color science, has been applied on spherical particles embedded in nonabsorbing medium, and their optical responses including reflectance, transmittance and absorption has been studied over solar spectrum, with special emphasis on VIS region. The effect of various indices of refraction, particle sizes and volume fractions has been further investigated. Obtained results reveal that, pigments with different fundamental and morphological structures represent interesting optical behavior which is very promising in optimization of spectrally selective pigmented coatings. The results from MF model were subsequently validated using spectrophotometric measurements on Titanium dioxide nanopigments coated on white polyester substrate, which represented a good agreement with collected data from MF model.