Functional indium oxide-based thin-film coatings with variable light transmission

Building Materials

 One of the directions of energy-saving technologies development in the public works construction is associated with the engineering of glazing materials that allow regulating light and heat flux passing through them. Known solutions are associated with the use of multilayer materials with special optical thin-film electrochromic coatings. This work presents the results of the functional properties study of single-layer transparent conductive thin-film coatings based on tin-doped indium oxide (ITO films), formed on a glass substrate by magnetron sputtering. It is shown that, under conditions of cathodic treatment in a potentiodynamic mode at certain threshold potentials Ep in aqueous and aqueous-ethanol solutions, the introduction of hydrogen atoms into surface layers is observed, leading to a decrease in the transmittance Tx to ~10% and the transition of ITO films to a colored state. It was found that the introduction of hydrogen atoms is accompanied by the formation of hydrogen-indium bronzes with the general formula HxIn2O3, the composition of which depends on the pH of the solution. Indium bronzes formed in a neutral 3% NaCl solution are characterized by a low value of the x index, high conductivity and reversibility of the coloration-discoloration processes, i.e. have electrochromic properties. Indium bronzes formed in 1M aqueous and aqueous-ethanol KOH solutions have higher values of the x index, low conductivity and irreversibility of the coloring process. Increase bronzes conductivity due to the introduction of carbon nanoparticles into the outer layers of ITO films does not affect the reversibility of the coloration-discoloration processes. The results obtained can serve as a basis for the creation of a wide range of modern improved glass and double-glazed windows with an adjustable value of light transmittance.