1. Saarland University, Inorganic Solid-State Chemistry, Campus C4 1, 66123 Saarbrücken, Germany
2. INM – Leibniz Institute for New Materials, 66123 Saarbrücken, Germany
3. Saarland University, Department of Materials Science and Engineering, 66123 Saarbrücken, Germany
4. Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Straße 2, 17489 Greifswald, Germany
5. Physics Department, Saarland University, Campus D2.2, 66123 Saarbrücken, Germany
6. Saarene – Saarland Center for Energy Materials and Sustainability, 66123 Saarbrücken, Germany