Solid-state dewetting of La0.6Sr0.4CO0.2Fe0.8O3 +/-delta thin films during annealing

Porous La0.6Sr0.4CO0.2Fe0.8O3 +/-delta (LSCF) thin film cathodes were fabricated by spray pyrolysis and pulsed laser deposition (PLD). These films show nanometer sized grains and a thickness < 1 mu m. They are dense after deposition and develop porosity upon annealing at 600-900 degrees C. Sprayed films develop roughly twice the porosity of films deposited by PLD. Solid-state dewetting similar to metallic films is proposed as the mechanism for the pore formation. The amount of porosity can be tailored by the deposition process, the annealing conditions and the chemistry of the precursor. The connection between porosity and electrical conductivity was also investigated. (c) 2007 Elsevier Ltd. All rights reserved.