Filter paper-templated preparation of ZnO thin films and examination of their gas-sensing properties

ZnO thin films prepared by using quantitative filter paper as a template and Zn(CHsCO2)2·2H2O ethanol precursor solution were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of sample calcination temperature, precursor concentration and filter paper types were studied, and the growth process was investigated by infra-red (IR) spectroscopy and thermogravimettic analysis/differential thermal analysis (TGA/DTA). The results show that samples soaked in a 1.5 mol/L Zn( CH3 CO2 )2.2 H2O ethanol solution and calcined at 600 ℃ yield ZnO films of uniform particle size, approximately 30, 40 and 50 nm, for fast-, medium- and slow-speed filter papers, respectively. The formaldehyde gas sensing properties of the ZnO nanoparticles were tested, showing that the material prepared from fast-speed filter paper has a higher response to 120-205 ppm formaldehyde at 400 ℃ than that prepared from medium- or slow-speed paper, which depends on the particle size.