Mechanism and characteristics of porous ZnO films by sol–gel method with PEG template

Porous ZnO thin films have been prepared on glass substrates via sol–gel method using polyethylene glycol (PEG) as organic template, zinc acetate as precursor, ethanol as solvent and diethanolamine as chelating agent. A model concerning the pore formation was suggested that PEG taking zinc oligomers would exclude the ethanol solvent, which results in the phase separation of this system. The experiment results showed that the thickness of the film obtained by six dip-coating is about 220 nm. The crystal structure of the ZnO films was hexagonal wurtzite by X-ray diffraction pattern analysis. And, the transmittance spectrum gave a high transmittance of 80% in the visible region.