Electrostatic spray assembly of nanostructured La0.7Ca0.3CrO3-delta films

The deposition of La0.7Ca0.3CrO3-delta (LCC) thin films was studied in detail by electrostatic spray deposition, considering the functions of deposition temperature, substrate material, and solvent composition. The microstructures of LCC films, which varied from porous reticulated models and cagelike particles to interconnect nanowire structures, can be effectively assembled. With increasing substrate temperature, the porosity decreases considerably; the pore and pore-wall sizes both became smaller. When changing the substrate material from nickel, aluminum, and alumina substrates to copper substrate, the microstructure of LCC film converted from the porous reticulated model to the cagelike particle model, as determined by the bigger contact angle on the copper substrate than that on other substrates. A qualitative mechanism involved in the formation of various microstructures is presented. Moreover, by changing the solvent composition, the layer morphology may also be significantly changed from the porous reticulated model to interconnect nanowire structure. (c) 2007 The Electrochemical Society.