Benzodithiophene‐based poly(aryleneethynylene)s: Synthesis, optical properties, and applications in organic solar cells

The synthesis and characterization of building block of ethynylene‐substituted benzo[1,2‐ b :4,5‐ b ′]dithiophene (BDT), and its application in the construction of poly(aryleneethynylene)s (PAEs) are described in this article. Alkoxy‐substituted BDT and thiazolothiazole are selected as the other copolymerized units, and polymers of PEBBDT and PEBTTZ were synthesized by Pd‐catalyzed Sonogashira coupling reaction. These polymers showed intense interchain π–π interaction and deep HOMO levels (≤ −5.50 eV). Bulk heterojunction solar cell fabricated using PEBBDT or PEBTTZ as electron donor and PC 61 BM as acceptor display power conversion efficiency of 0.85 and 2.40%, respectively, under the illumination of AM1.5G, 100 mW cm −2 . This study shows good prospect for the application of PAEs‐type polymers in organic solar cell.