Preparation of ZnO porous thin films by sol–gel method using PEG template

ZnO porous thin films were prepared on glass substrates by sol–gel method with polyethylene glycol (PEG) as organic template, Zn(CH3COO)2·2H2O as precursor, ethanol as solvent and NH(C2H2OH)2 as chelating agent. IR, TG–DTA, XRD and SEM analyzed the characteristics of films and the chemical and physical changes during sol–gel process. The effects of Zn(CH3COO)2 concentration, PEG content and water bath temperature on the characteristics of films were also discussed. The results showed that the morphology of porous ZnO thin films strongly depended on these processing factors. ZnO porous thin film could be made due to the better phase separation according to the following conditions: Zn(CH3COO)2 concentration was 0.6 mol/l and PEG content was 0.7 g in 50 ml solvent. The sol should be pretreated in water bath at 70 °C before dipping, then sintered at 500 °C for 1 h.