Preparation of Transparent Thick Films by Electrophoretic Sol‐Gel Deposition Using Phenyltriethoxysilane‐Derived Particles

Thick films were prepared on glass substrates coated with indium tin oxide (ITO) via electrophoretic deposition using sols that contained phenylsilsesquioxane (PhSiO 3/2 ) particles derived from phenyltriethoxysilane. The transparency of the thick PhSiO 3/2 films was significantly improved via heat treatment at temperatures >200°C. Scanning electron microscopy observation showed that the thick films changed in morphology, from aggregates of particles with several open spaces among the particles to a monolith with no open spaces after the heat treatment. Transparent films ~3 µm thick were obtained when the films were heat‐treated at a temperature of 400°C for 2 h.