Grain-size effects on gas response in nanostructured Gd0.9Ba0.1CoO3

The perovskite Gd(0.9)Ba(0.1)CoO3 was prepared via solution and solution-polymerization methods in aqueous media. The thermal decomposition of precursor powders produced well crystallized nanostructured materials possessing an extensive nanoporosity. The average particle size obtained by the solution route was 150 nm, whereas by the solution-polymerization method was 61 nm. The characterization of gas response, performed on thick-films, revealed that the electrical resistance variation increases with reducing grain size. In oxygen, the films prepared with powder of solution-polymerization registered an increment of 1000%, compared to the powder made by the solution route, whereas in carbon dioxide was 1100%.