1. Department of Solid State Physics (Member of National Photovoltaic Laboratory, Poland), Faculty of Physics and Applied Informatics, University of Lodz, Pomorska 149/153, 90-236 Łódź, Poland
2. Division of Physical Chemistry, Department of Chemistry, Lund University, P.O. Box 124, 22100 Lund, Sweden
3. Department of Physics, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia