Structural and electrical properties of thin films of Pr0.8Sr0.2Fe0.8Ni0.2O3−δ

Pr0.8Sr0.2Fe0.8Ni0.2O3−δ (PN22) films have been deposited at different temperatures on yttria-stabilized zirconia (YSZ) substrates by pulsed laser deposition (PLD) for application to thin film solid oxide fuel cell cathodes. The structure of the films was analysed by X-ray diffraction (XRD) and atomic force microscopy (AFM). A marked influence in the structural properties of the substrate temperature has been found but not of the composition. Samples deposited at temperatures below 700 °C are amorphous, with granular aspect, and with decreasing roughness with the temperature. Meanwhile, the films at 700 °C are polycrystalline and exhibit a needle-shaped surface, with the highest roughness observed. Additionally, the conducting behaviour of the films has been studied by electrochemical impedance spectroscopy (EIS) and their cathodic area specific resistance (ASR) was determined. The main part of the impedance of the testing cells is due to the electrode. The ASR values of the films of PN22 are lower than those of Pr0.9Sr0.1Fe0.8Ni0.2O3−δ (PN12), being the lowest 0.5 Ω cm2 at 850 °C for the sample PN22 deposited at room temperature.