1. Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena 3/7, Riga, 1048, Latvia
2. Department of Chemistry, National Central University, Taoyuan, 32001, Taiwan
3. Faculty of Physics, Vilnius University, Sauletekio av. 3, Vilnius, 10257, Lithuania
4. Institute of Solid State Physics, University of Latvia, Kengaraga 8, Riga, 1063, Latvia