Synthesis of La 0.8Sr 0.2Co 0.5Ni 0.5O 3-δ thin films for high sensitivity CO sensing material using the Pechini process

Abstract

A sol–gel technique including the Pechini process followed by a spin-coating procedure has been employed for the preparation of nano-sized La 0.8Sr 0.2Co 0.5Ni 0.5O 3-δ (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 c) 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 c 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 c value to prepare the precursor powder and calcined at the temperature of 650°C, a thin film of perovskite structure with average grain sizes of ∼60 nm can be obtained.