[Abstract]

We designed and synthesized two new acceptor-donor-acceptor (A-D-A) small molecules SM-1 and SM-2 by connecting benzodithiophene (BDT) and dithienopyrrole (DTP) are electron rich donor units, dialkoxyphenylenedithiophene as π-spacer and 2,4 thiazolidinedione as terminal acceptor unit respectively. The SM-1 and SM-2 showed broad absorption windows with optical band gaps of 1.7 and 1.8 eV respectively, and also possess high thermal stabilities and suitable energy levels for optoelectronic applications. Especially, SM-2 shows a maximum power conversion efficiency of 1.26%, and hole mobility of 4.6 × 10−3 cm2/V.s in conventional organic solar cells and organic field effect transistor devices respectively.