Back
 NS  Vol.2 No.7 , July 2010
Synthesis, structural characterization and formation mechanism of giant-dielectric CaCu3Ti4O12 nanotubes
Abstract: A capillary-enforced template-based method has been applied to fabricate calcium copper titanate (CaCu3Ti4O12, CCTO) nanotubes (diameter ~200 nm) by filling sol-gel CCTO precursor solution into the nanochannels of porous anodic aluminum oxide (AAO) templates, subsequent heating for phase formation and fi- nally the removal of nano-channel templates by applying basic solution. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) equipped with Energy-dispersive X-ray spectroscopy (EDX) have been employed to characterize the morphology, structure, and composition of as-prepared nanotubes. XRD and selected-area electron diffraction (SAED) in-vestigations demonstrated that postannealed (750○C for 1 h) CCTO nanotubes were poly-crystalline with a cubic pseudo-perovskite cry- stal structure. The FE-SEM and TEM results showed that CCTO nanotubes were of uniform diameter (~200 nm) throughout their length. High resolution TEM (HRTEM) analysis confirm- ed that the obtained CCTO nanotubes are made of randomly aligned nano-particles 5-10 nm in size. EDX analysis demonstrated that stoichi- ometric CaCu3Ti4O12 was formed. The possible formation mechanism of CCTO nanotubes in the AAO template is discussed.
Cite this paper: Banerjee, N. and Krupanidhi, S. (2010) Synthesis, structural characterization and formation mechanism of giant-dielectric CaCu3Ti4O12 nanotubes. Natural Science, 2, 688-693. doi: 10.4236/ns.2010.27085.
References

[1]   Iijima, S. (1991) Helical microtubules of graphitic carbon. Nature, 354(6348), 56-58.

[2]   Hu, J., Odom, T.W. and Lieber, C.M. (1999) Chemistry and physics in one dimension: Synthesis and properties of nanowires and nanotubes. Accounts of Chemical Research, 32(5), 435-445.

[3]   Atzke, G.R.P., Rumeich, F.K. and Nesper, R. (2002) Based on oxide nanotubes and nanorods ? anisotropic building blocks for future nanotechnology. Angewandte Chemie, 114(14), 2554-2571.

[4]   Goldberger, J., He, R., Zhang, Y., Lee, S., Yan, H., Choi, H. and Yang, P. (2003) Single-crystal gallium nitride na-notubes, Nature, 422(6932), 599-602.

[5]   Lee, S.B., Mitchell, D.T., Rofin, L.T., Ne vanen, T.K., S?derlund, H. and Martin, C.R. (2002) Antibody-based bio-nanotube membranes for enantiomeric drug separa-tions. Science, 296(5576), 2198-2200.

[6]   Sha, J., Niu, J., Ma, X., Xu, J., Zhang, X., Yang, Q. and Yang, D. (2002) Silicon nanotubes. Advanced Materials, 14(17), 1219-1224.

[7]   Junquera, J. and Ghosez, P. (2003) Critical thickness for ferroelectricity in perovskite ultrathin films. Nature, 422(6931), 534-539.

[8]   Wang, Y. and Santiago-Aviles, J.J. (2004) Synthesis of lead zirconate titanate nanofibres and the Fourier-transform infrared characterization of their metallo-organic decomposition process. Nanotechnology, 15, 32.

[9]   Luo, Y., Szafraniak, I., Zakharo, N.D., Nagarajan, V., Steinhart, M., Ehrspohn, R.B.W., Endorff, J.H.W., Ra-mesh, R. and Alexe, M. (2003) Nanoshell tubes of fer-roelectric lead zirconate titanate and barium titanate. Ap-plied Physics Letters, 83(5377), 440-442.

[10]   Chu, M.W., Szafraniak, I., Scholz, R., Harnagea, C., Hesse, D., Alexe, M. and Gosele, U. (2004) Impact of misfit dislocations on the polarization instability of ep-itaxial nanostructured ferroelectric perovskites. Nature Materials, 3(2), 87-90.

[11]   Roelofs, A., Schneller, I., Szot, K. and Waser, R. (2002) Piezoresponse force microscopy of lead titanate nano-grains possibly reaching the limit of ferroelectricity. Ap-plied Physics Letters, 81(27), 5231-5233.

[12]   Hernandez, B.A., Chang, K.S., Fisher, E.R. and Dorhout, P.K. (2002) Sol-Gel template synthesis and characteriza-tion of batio3 and pbtio3 nanotubes. Chemistry of Mate-rials, 4, 480.

[13]   Zhang, X.Y., Zhao, X., Lai, C.W., Wang, J., Tang, X.G. and Dai, J.Y. (2004) Synthesis and piezoresponse of highly ordered Pb(Zr0.53Ti0.47)O3 nanowire arrays. Applied Physics Letters, 85(18), 4190-4192.

[14]   Singh, S. and Krupanidhi, S.B. (2007) Synthesis and structural characterization of Ba0.6Sr0.4TiO3 nanotubes. Physics Letter A, 367(4-5), 356-359.

[15]   Subramanian, M.A., Li, D., Duan, N., Reisner, B.A. and Sleight, A.W. (2000) High dielectric constant in ACu3Ti4O12 and ACu3Ti3FeO12 phase. Journal of Solid State Chemistry, 151(2), 323-325.

[16]   Liu, J. J., Sui, Y.C., Duan, C.-G., Mei, W.-N., Smith, R.W., and Hardy, J.R. (2006) CaCu3Ti4O12: Low-temperature synthesis by pyrolysis of an organic solution. Chemistry Materials, 18(16), 3878-3882.

[17]   Sinclair, D.C., Adams, T.B., Morrison, F.D. and West, A.R. (2002) CaCu3Ti4O12: One-step internal barrier layer capacitor. Applied Physics Letters, 80(12), 2153-2155.

[18]   Liu, J., Duan, C., Yin, W., Mei, W.N., Smith, R.W. and Hardy, J.R. (2004) Large dielectric constant and max-well-wagner relaxation in Bi2∕3Cu3Ti4O12. Physics Review B, 70, 144106.

[19]   Lunkenheimer, P., Bobnar, V., Pronin, A.V., Ritus, A.I., Volkov, A.A. and Loidl, A. (2002) Origin of apparent colossal dielectric constants. Physics Review B, 66, 052105.

[20]   Thomas, P., Dwarakanath, K., Varma, K.B.R. and Kutty, T.R.N. (2008) Nanoparticles of the giant dielectric material, CaCu3Ti4O12 from a precursor route. Journal of Physics and Chemistry of Solids, 69(10), 2594-2604.

[21]   Zhang, X.Y., Lai, C.W., Zhao, X., Wang, D.Y. and Dai, J.Y. (2005) Synthesis and ferroelectric properties of mul-tiferroic BiFeO3 nanotube arrays. Applied Physics Letters, 87, 143102.

[22]   Wang, Y. and Cao, G. (2007) Synthesis and electrochem-ical properties of InVO4 nanotube arrays. Journal of Materials Chemistry, 17(2298), 894-899.

 
 
Top