Structural, morphological and electrical properties of Sm-Gd Co-doped ceria thin films for micro-solid oxide fuel cells

Thin film electrolytes of Sm and Gd doubly co-doped ceria, namely, Ce0.8Sm0.1Gd0.1O1.90 (CSGO) deposited by pulsed laser deposition (PLD) technique have been investigated. The influence of oxygen partial pressure (pO(2)) on structural and morphological properties of CSGO thin films deposited on Si (111) substrate was studied by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM) techniques. The XRD and FESEM results showed that the films were polycrystalline cubic structure with (111) oriented columnar structure. The co-doping strategy has strongly helped to stabilize the Ce4+ state as the lattice parameter of the films did not show any significant change under the influence of pO2 in the range of 2 x 10(-4)-3 x 10(-2) mbar. The electrical conductivity and activation energy of CSGO thin film supported on NiO-GDC10 anode were found to be 0.48 mS.cm(-1) and 0.5 eV respectively. Determination of significantly lower Ce3+ concentration (27%) in CSGO film by X-ray photon electron spectroscopy (XPS) suggests that Sm-Gd co-doping has strongly suppressed the conversion of Ce4+ to Ce3+ in the overall composition. (C) 2020 Elsevier B.V. All rights reserved.