Combined TiO2/SnO2 material with adding Pt by sol-gel technology for humidity sensor

In this work, the sensitivity of the humidity sensor based on hybrid thin films of TiO2/SnO2 nanostructure with Pt dopant was successfully increased. The humidity-sensitive materials, TiO2/SnO2, were prepared by sol gel technology. The microstructure of the sensing film after calcination was investigated by Field Emission gun Scanning Electron Microscopy (FESEM) and revealed that the metal oxide hybrid had about 10 rim grain size. On order to study the effect of Pt dopant on the humidity-sensitive responses, 1 to 10 ml of Pt standard solution was added into the colloidal solution. To compare the humidity sensor of Pt dopant with that of no Pt dopant, operational frequencies and electrode spacings were set under the relative humidity from 30 % to 95 % at the ambient temperature of 22 degrees C. We demonstrated that adding Pt dopant remarkably enhances the sensitivity of TiO2/SnO2 humidity sensor, and further decreased the TiO2/SnO2 resistance, which was 3.3 times lower than that without Pt dopant at high humidity.