1. University of Strasbourg; CNRS; ISIS UMR 7006; 8 allée Gaspard Monge F-67000 Strasbourg France
2. Laboratory of Organic Matter Physics; University of Nova Gorica; Vipavska 11c SI-5270 Ajdovšcˇina Slovenia
3. Istituto per la Microelettronica e Microsistemi (IMM); Consiglio Nazionale delle Ricerche; via Gobetti 101 40129 Bologna Italy