High-Efficiency Large-Bandgap Material for Polymer Solar Cells

High‐molecular‐weight conjugated polymer HD‐PDFC‐DTBT with N‐(2‐hexyldecyl)‐3,6‐difluorocarbazole as the donor unit, 5,6‐bis(octyloxy)benzothiadiazole as the acceptor unit, and thiophene as the spacer is synthesized by Suzuki polycondensation. HD‐PDFC‐DTBT shows a large bandgap of 1.96 eV and a high hole mobility of 0.16 cm2 V−1 s−1. HD‐PDFC‐DTBT:PC71BM‐based inverted polymer solar cells (PSCs) give a power conversion efficiency (PCE) of 7.39% with a Voc of 0.93 V, a Jsc of 14.11 mA cm−2, and an FF of 0.56. HD‐PDFC‐DTBT with a large bandgap of 1.96 eV is synthesized and used for the fabrication of polymer solar cells (PSCs). A power conversion efficiency (PCE) of 7.39% with a Voc of 0.93 V, a Jsc of 14.11 mA cm−2, and an FF of 0.56 is obtained in inverted PSCs with (6,6)‐phenyl‐C71‐butyric acid methyl ester (PC71BM) as the acceptor without using any processing additive.