1. Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga, Latvia
2. G. Liberts’ Innovative Microscopy Centre, Department of Technology, Institute of Life Sciences and Technology, Daugavpils University, Parades Street 1a, LV-5401 Daugavpils, Latvia
3. Institute of Physics, University of Tartu, West Ostwaldi Street 1, 50412, Tartu, Estonia
4. Department of Chemistry and Center for Sustainable Systems Design, Paderborn University, 33098 Paderborn, Germany