1. Istituto Officina dei Materiali-CNR, Area Science Park, S.S.14, Km 163.5, 34149 Trieste, Italy
2. Department of Materials Chemistry, National Institute of Chemistry, Hajdrihova 19, 1001 Ljubljana, Slovenia
3. Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria 16, 20133 Milano, Italy