Effect of Chlorine or Ester Incorporation on Diketopyrrolopyrrole -Based Polymeric Semiconductors

Abstract Organic photovoltaic materials incorporating either chlorine atoms or ester groups have been studied as replacement strategy for fluorinated compounds. However, the characteristics of such materials when used in organic field-effect transistors (OFETs) remain unclear. The present work synthesized three polymers via the copolymerization of diketopyrrolopyrrole (DPP) with monothiophene units having no substituents or incorporating either chlorine atoms or ester groups. All three materials were found to have similar photophysical and electrochemical properties even though their repeating units had different substituents. The maximum hole mobility values for the polymer specimens were determined to be 0.37 cm2 V−1 s−1. The introduction of chlorine into the DPP-based polymer generated an amorphous semiconductor material that makes it a very promising candidate for commercial OFETs since its properties are independent of fabrication conditions. The new polymeric semiconductors demonstrated herein suggest the viability of such materials with regard to incorporation in organic field-effect transistors.