Sol–gel synthesis of mesoporous CaCu3Ti4O12 thin films and their gas sensing response

✍ Scribed by R. Parra; R. Savu; L.A. Ramajo; M.A. Ponce; J.A. Varela; M.S. Castro; P.R. Bueno; E. Joanni

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 862 KB
• Volume: 183
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1016/j.jssc.2010.03.033

✦ Synopsis

A new sol-gel synthesis procedure of stable calcium copper titanate (CaCu 3 Ti 4 O 12 -CCTO) precursor sols for the fabrication of porous films was developed. The composition of the sol was selected in order to avoid the precipitation of undesired phases; ethanol was used as solvent, acetic acid as modifier and poly(ethyleneglycol) as a linker agent. Films deposited by spin-coating onto oxidized silicon substrates were annealed at 700 1C. The main phase present in the samples, as detected by X-ray diffraction and Raman spectroscopy, was CaCu 3 Ti 4 O 12 . Scanning electron microscopy analysis showed that mesoporous structures, with thicknesses between 200 and 400 nm, were developed as a result of the processing conditions. The films were tested regarding their sensibility towards oxygen and nitrogen at atmospheric pressure using working temperatures from 200 to 290 1C. The samples exhibited n-type conductivity, high sensitivity and short response times. These characteristics indicate that CCTO mesoporous structures obtained by sol-gel are suitable for application in gas sensing.