title: Derivatives of 4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-4,9-dione: synthesis and properties.
abstract: A new family of organic semiconducting materials (1-4) integrating the structural components of thiophene and fluorene into a single molecular entity was synthesized and characterized. Optical and electrochemical properties of these previously unknown 4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-4,9-dione derivatives were studied in detail. These materials possess unique optical properties with the longest wavelength absorption maxima around 500-800 nm, which gradually reached a saturation limit with the total number of thiophene units approaching eight. They also display dramatic change in the redox properties with increasing conjugation chain lengths. A thin film of oligomer 3 prepared by a solution-casting method showed a well-ordered solid-state structure according to X-ray diffraction analysis.
authors.affiliation: Departments of Chemistry and Chemical Engineering, University of Rochester, Rochester, New York 14627, USA.
authors.forename: Chunchang
authors.initials: C
authors.lastname: Zhao
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Man-Kit
authors.initials: MK
authors.lastname: Ng