Structural characterizations of organo-capped barium titanate nanoparticles prepared by the wet chemical route

In the present study, nanoscale barium titanate particles were chemically p repared with organic shells on their surfaces. Their chemical and physical structures were characterized by FT-IR, FT-Raman, XRD, and XPS. Based on th e results of characterizations, it can be concluded that the presence of or ganic ligands greatly influences the nucleation and surface chemistry of Ba TiO3 nanoparticles. Surface Ti4+ tends to bond to stearate ions instead of the previous Ba2+ in the starting materials. The usual preferable orientati on growths of lattice, i.e., (101), (111), and (200), were significantly re strained due to surface coordination. Although poor crystallinity was obser ved, a tetragonal phase of BaTiO3 nuclei could be inferred from both XRD an d Raman patterns. Finally, the formation mechanism and structural model of organo-capped nanoparticles are discussed. (C) 2001 Academic Press.