Influence of substrate temperature on structural, morphological and electrical properties of La0.6Sr0.4Co0.2Fe0.8O3 thin films for IT-SOFCs

The crack free, homogeneous, nanocrystalline La0.6Sr0.4Co0.2Fe0.8O3 thin films have been deposited on Ce0.9Gd0.1O1.95 electrolyte by the spray pyrolysis technique. The films with typically 1-2 μm thickness, get crystallized on annealing at 800 °C. In the present work, the effect of substrate temperature on microstructure, crystallization and conductivity has been systematically studied. The deposition of film at 300 °C shows higher in plane electrical conductivity of 26.6 S cm−1 with activation energy, Ea = 0.23 eV. The higher conductivity attributes to uniform, thin and dense microstructure of thin films. No interfacial reaction products between La0.6Sr0.4Co0.2Fe0.8O3 and Ce0.9Gd0.1O1.95 were detected upon annealing at 800 °C/4 h. The uniformity and porosity distribution as a function of deposition temperature clarified from Scanning Electron micrograph.