A donor-acceptor-donor (D-A-D) molecule based on 3-alkoxy-4-cyanothiophene and dithienopyrrole units as active material for organic solar cells

A symmetrical donor-acceptor-donor D-A-D system built by connecting two dithienopyrrole donor blocks to a central electron acceptor obtained by dimerization of 3-alkoxy-4-cyanothiophene has been synthesized and characterized. The compound combines a high photoluminescence efficiency with a broad absorption spectrum in the solid state and a band gap of 1.70 eV. A preliminary evaluation of the potentialities of this type of compound as donor material in bulk heterojunction solar cells using PC61BM as electron acceptor is presented.