Direct Formation of Zn−Al Layered Double Hydroxide Films with High Transparency on Glass Substrate by the Sol−Gel Process with Hot Water Treatment

Amorphous Al 2 O 3 −ZnO thin films with various Zn/Al ratios were prepared on glass substrates by the sol−gel method with a heat treatment at 400 °C for 30 min followed by immersion of the films in distilled water at 100 °C to form nanocrystalline Zn−Al layered double hydroxide (LDH) with hexagonal structure. Zn−Al LDH nanocrystals were precipitated on the amorphous Al 2 O 3 −ZnO films with various Zn/Al ratios, and the maximum amount of nanocrystals was formed on the film of the Zn/Al atomic ratio of unity. Zn−Al LDH crystals with the size of 200−500 nm have been precipitated on glass substrates through hot water treatment at temperatures lower than 100 °C.