Bay‐annulated indigo based near‐infrared sensitive polymer for organic solar cells

Abstract

ABSTRACTA new conjugated polymer (PBAIIDTT) based on bay‐annulated indigo and indacenodithieno[3,2‐b]thiophene was designed, synthesized, and characterized. PBAIIDTT shows strong absorption in 400–500 and 600–800 nm, and its HOMO and LUMO energy levels are −5.45 eV and −3.65 eV, respectively. In organic field‐effect transistors, the polymer exhibits a relatively high hole mobility of 0.39 cm2 V−1 s−1. PBAIIDTT was added to poly(3‐hexylthiophene) (P3HT) and phenyl‐C61‐butyric acid methyl ester (PC61BM) based organic solar cells. Ternary blend solar cells with 10% PBAIIDTT show an increased short circuit current density due to the broadened photocurrent generated in the near‐infrared region, and a power conversion efficiency of 3.78%, which is higher than that of the P3HT:PC61BM binary control devices (3.33%). © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 213–220