ITO@SiO₂ and ITO@{M₆Br₁₂}@SiO₂ (M = Nb, Ta) nanocomposite films for ultraviolet-near infrared shielding

Transparent optical thin films for energy saving applications have recently gained substantial prominence for functional window processes. In this study, highly visible transparent nanocomposite films with ultraviolet (UV) and near-infrared (NIR) blocking capabilities are reported. Such nanocomposite films, prepared by electrophoretic deposition on ITO-coated glass, are composed of indium tin oxide (ITO) nanocrystals (9 nm) and octahedral metal atom clusters (1 nm, Nb₆ or Ta₆) embedded into silica nanoparticles (∼80 nm). The functional silica nanoparticles were prepared by a reverse microemulsion process. The microstructural characterization proved that ITO nanocrystals are centered in the silica nanoparticles, whereas the metal atom clusters are homogeneously distributed in the silica matrix. The optical absorption spectra of these transparent nanocomposite films exhibit distinct and complementary contributions from their ITO nanoparticles and metal atom clusters (absorption in the UV range) and from the ITO layer on silica.