1. CNR‐IMM Strada VIII Catania 5 95121 Italy
2. Department of Physics and Astronomy University of Catania Via Santa Sofia 64 Catania 95123 Italy
3. Department of Physics and Chemistry Emilio Segré University of Palermo Via Archirafi 36 Palermo 90143 Italy
4. AtenCenter University of Palermo Viale delle Scienze Ed.18 Palermo 90128 Italy
5. Centre for Energy Research Institute of Technical Physics and Materials Science Konkoly‐Thege ut 29–33 Budapest 1121 Hungary
6. Institute of Electrical Engineering SAS Dúbravská cesta 9 Bratislava 84104 Slovakia