Emission properties and solid-state aggregation in poly(fluorene-thiophene-S,S-dioxide) and its model oligomer

We report on the preparation of both 2,5-di(9,9-dimethyl)fluorenyl-3,4-dihexyl-thiophene-S,S-dioxide and the related polymer with longer alkyl substitutions at 9 position. The optical, structural, and morphological characterizations of crystals and films showing noticeable EL properties are presented. Light emitting diodes (LEDs) show for the first time a good external efficiency (10-1) for a polymer containing S,S-dioxide groups.