[1] Riga Tech Univ, Fac Mat Sci & Appl Chem, Res Lab Funct Mat Technol, P Valdena 3-7, LV-1048 Riga, Latvia
[2] Univ Tartu, Inst Phys, W Ostwaldi 1, EE-50411 Tartu, Estonia
[3] Univ Tartu, Inst Chem, Ravila 14A, EE-50411 Tartu, Estonia
[4] Riga Tech Univ, Fac Mat Sci & Appl Chem, Inst Tech Phys, Paula Valdena 3-7, LV-1048 Riga, Latvia