1. Institut für Physik; Humboldt-Universität zu Berlin; Brook-Taylor-Str. 6 D-12489 Berlin Germany
2. Helmholtz-Zentrum Berlin für Materialien und Energie GmbH; Albert-Einstein-Str. 15 D-12489 Berlin Germany
3. Elettra-Sincrotrone Trieste S.C.p.A; S.S. 14 Km 163.5 I-34149 Basovizza (TS) Italy
4. IOM CNR Laboratorio TASC; Basovizza (TS) 34149 Italy
5. Center for Organic Photonics and Electronics (COPE); School of Chemistry and Biochemistry; Georgia Institute of Technology; GA Atlanta 30332-0400 USA