Low temperature synthesis and optical properties of CaTiO3 nanoparticles from Ca(NO3)2•4H2O and TiO2 nanocrystals

Choosing low-melting-point Ca(NO3)(2)center dot 4H(2)O and high-reactive-activity TiO2 nanocrystals as the raw materials, a simple and cost-effective route was developed for the synthesis of CaTiO3 nanoparticles at 600 degrees C, which is much lower than that (about 1350 degrees C) used in the conventional solid state reaction methods. X-ray diffraction, energy dispersive X-ray spectroscopy and field emission scanning electron microscopy revealed the formation of orthorhombic phase CaTiO3 nanoparticles with oxygen-deficiency at the surface. UV-vis absorption spectrum of the as-obtained CaTiO3 nanoparticles displayed an absorption peak centered at around 325 nm (3.8 eV), together with a tail at lower energy side. Room temperature photoluminescence spectrum of the as-obtained CaTiO3 nanoparticles upon laser excitation at 325 nm demonstrated a strong and broad visible light emission ranging from about 527 to 568 nm, which may be originated from the surface states and defect levels. (C) 2011 Elsevier B.V. All rights reserved.