Sol-gel synthesis of mesoporous CaCu{sub 3}Ti{sub 4}O{sub 12} thin films and their gas sensing response

Journal Article · Tue Jun 15 00:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.03.033· OSTI ID:21432455

Parra, R ^[1]; Savu, R ^[2]; Ramajo, L A; Ponce, M A ^[1]; Varela, J A ^[2]; Castro, M S ^[1]; Bueno, P R ^[2]; Joanni, E ^[2]

---

1. Instituto de Investigaciones en Ciencia y Tecnologia de Materiales (INTEMA), CONICET-UNMdP, J. B. Justo 4302, B7608FDQ Mar del Plata (Argentina)
2. Instituto de Quimica, UNESP, Rua F. Degni s/n, 14800-900 Araraquara, SP (Brazil)

A new sol-gel synthesis procedure of stable calcium copper titanate (CaCu{sub 3}Ti{sub 4}O{sub 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 {sup o}C. The main phase present in the samples, as detected by X-ray diffraction and Raman spectroscopy, was CaCu{sub 3}Ti{sub 4}O{sub 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 {sup o}C. 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. - Graphical abstract: A sol-gel synthesis procedure toward stable CaCu{sub 3}Ti{sub 4}O{sub 12}-precursor sols avoiding the precipitation of undesired compounds is proposed. Films deposited by spin-coating onto oxidized silicon substrates were annealed at 700 {sup o}C. The thickness varied between 200 and 400 nm depending on sol composition. The films, tested as gas sensors for O{sub 2}, showed n-type conductivity, good sensitivity and short response times.

• OSTI ID: 21432455
• Journal Information: Journal of Solid State Chemistry, Vol. 183, Issue 6; Other Information: DOI: 10.1016/j.jssc.2010.03.033; PII: S0022-4596(10)00123-4; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
ACETIC ACID
ANNEALING
ATMOSPHERIC PRESSURE
CALCIUM COMPOUNDS
COPPER COMPOUNDS
NANOSTRUCTURES
OXYGEN
SCANNING ELECTRON MICROSCOPY
SENSORS
SILICON
SOL-GEL PROCESS
SPIN-ON COATING
TEMPERATURE RANGE 0400-1000 K
THIN FILMS
TITANATES
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
CARBOXYLIC ACIDS
COHERENT SCATTERING
DEPOSITION
DIFFRACTION
ELECTRON MICROSCOPY
ELEMENTS
FILMS
HEAT TREATMENTS
MICROSCOPY
MONOCARBOXYLIC ACIDS
NONMETALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
SCATTERING
SEMIMETALS
SURFACE COATING
TEMPERATURE RANGE
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS