Preparation of oriented zinc oxide thin films by firing Zn–Al layered double hydroxide thin films

The Zn–Al layered double hydroxide (LDH) particles were prepared by heating aqueous solutions of Zn(NO3)2 and Al(NO3)3 with ethylenediamine at 348 K for 24 h. The obtained particles, which had sheet morphology, were well dispersed in water. The sol of LDH nanoparticles was dried on an alkali-free glass substrate and LDH thin films were obtained easily. Firing the LDH films at temperatures higher than 573 K produces a highly oriented zinc oxide film. The obtained films had orientation of zinc oxide (002) on the glass substrate. This orientation reflected that of the LDH films. The zinc oxide films showed more than 80% of the optical transmittance when the wavelength was 400 nm.

► Transparent thin films of Zn–Al layered double hydroxide (LDH) were prepared.
► Transparent zinc oxide films were obtained by firing the Zn–Al LDH films at 573 K.
► Oxide films obtained by firing Zn–Al LDH films had high orientation of ZnO (002).