1. Key Lab of Environment‐Friendly Chemistry and Applications of the Ministry of Education, College of Chemistry, Xiangtan University, , Xiangtan, 411105 China;2. National Center for Nanoscience and Technology, , Beijing, 100190 China;3. College of Materials and Chemical Engineering, Hainan University, , Haikou, 570228 China
Abstract:
Two electron‐deficient tetracyclic monomers, 6,9‐dibromo‐7,8‐bis(octyloxy)‐11H‐indeno[2,1‐b] quinoxalin‐11‐one ( M1 ) and 1,3‐bis(5′‐bromo‐4′‐hexylthiophen‐2‐yl)‐9H‐indeno[1,2‐b]thieno[3,4‐e]pyrazin‐9‐one ( M2 ), are synthesized through condensation of ninhydrin with aromatic diamines in good yields. Copolymerization of M1 with thiophene (Th) and dithieno[3,2‐b:2′,3′‐d]silole (DTS), and M2 with DTS affords three new D–A conjugated copolymers, P1 – P3, respectively . The optical, electrochemical, and photovoltaic properties of P1–P3 are investigated. P3 exhibits a broad absorption (300–1100 nm) and a low bandgap of 1.24 eV. Solar cells based on P3 /[6,6]‐phenyl C71 butyric acid methyl ester (PC71BM) blends afford a power conversion efficiency of 1.93% and a very broad spectral response (300–1020 nm).
