1. Department of Materials Science and Engineering, University of Ioannina, GR-45110
2. Department of Materials Science, University of Patras, GR-26504 Patras, Greece
3. Institute of Inorganic Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84536 Bratislava, Slovakia
4. Regional Centre of Advanced Technologies and Materials, Faculty of Science, Department of Physical Chemistry, Palacký University in Olomouc, CZ-77146 Olomouc, Czech Republic