skip to main content

SciTech ConnectSciTech Connect

Title: Heat treatment effect on the physical properties of cobalt doped TiO{sub 2} sol–gel materials

Cobalt doped and undoped TiO{sub 2} powders have been prepared by sol–gel technique and annealed at temperatures ranging from 400 °C to 1000 °C. The effects of annealing temperature on the structural, morphological and optical properties have been characterized by X-ray diffraction, transmission electron microscopy, electron energy-loss spectroscopy and diffuse reflectance spectroscopy. For all doped samples there is a general reduction of the band gap energy, in comparison with undoped samples prepared in the same conditions. More specifically, experimental results indicate that cobalt doping, occurring as Co{sup 2+} ion insertion into the TiO{sub 2} (Ti{sup 4+}) host lattice, inhibits the growth of the crystallites and delays the phase transformation from anatase to rutile. Moreover, at high temperature, a secondary phase (CoTiO{sub 3}) is found to coexist with highly crystalline rutile. These structural characteristics are discussed in relation with the observed general trends for the optical properties. - Highlights: • Cobalt doped and undoped TiO{sub 2} powders have been prepared by sol–gel route. • Doping makes the band gap narrower. • Doping delays the phase transformation from anatase to rutile. • Doping inhibits the growth of the crystallites. • At high annealing temperature a CoTiO{sub 3} phase coexists with highly crystallinemore » rutile.« less
Authors:
 [1] ;  [2] ; ;  [3] ; ;  [4]
  1. Institut Préparatoires aux Etudes d'Ingénieurs d'El-Manar, Université Tunis El Manar, Campus Universitaire, 2092 El Manar (Tunisia)
  2. (Tunisia)
  3. Laboratoire de Photovoltaique de Semi-conducteur et de Nanostructure, Centre de Recherches et des Technologies de l'Energie, Technopole borj cedria, Bp 95, hammamm lif 2050 (Tunisia)
  4. Laboratoire de Physique des Solides, UMR 8502 CNRS - Université Paris-Sud, Bât 510, 91405 Orsay cedex (France)
Publication Date:
OSTI Identifier:
22288676
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 85; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; COBALT; DOPED MATERIALS; ENERGY-LOSS SPECTROSCOPY; OPTICAL PROPERTIES; PHASE TRANSFORMATIONS; RUTILE; TITANATES; TITANIUM OXIDES; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION