Synthesis of La0.8Sr0.2Co0.5Ni0.5O3-δ thin films for high sensitivity CO sensing material using the Pechini process

A sol-gel technique including the Pechini process followed by a spin-coating procedure has been employed for the preparation of nano-sized La0.8Sr0.2Co0.5O3.8 (LSCN) thin films used as high sensitivity CO sensing materials. In the characterization of the material, X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis-thermogravimetric analysis (DTA-TG) and surface area analyses (BET equation) were used. The results showed that the molar ratio (R,.) of the citrate/metal ions in the gelation process is the critical factor to obtain a thin film with smooth surfaces, low porosity and homogeneous grain sizes. It is found that an R, value of 3.3 can produce the best results compared to other tested values of 4.0, 2.5, and 1.7. Taking this R. value to prepare the precursor powder and calcined at the temperature of 650degreesC, a thin film of perovskite structure with average grain sizes of similar to60 nm can be obtained. (C) 2002 Elsevier Science B.V. All rights reserved.