Narrow‐Bandgap Single‐Component Polymer Solar Cells with Approaching 9% Efficiency

Two narrow‐bandgap block conjugated polymers with a (D1–A1)–(D2–A2) backbone architecture, namely PBDB‐T‐ b ‐PIDIC2T and PBDB‐T‐ b ‐PTY6, are designed and synthesized for single‐component organic solar cells (SCOSCs). Both polymers contain same donor polymer, PBDB‐T, but different polymerized nonfullerene molecule acceptors. Compared to all previously reported materials for SCOSCs, PBDB‐T‐ b ‐PIDIC2T and PBDB‐T‐ b ‐PTY6 exhibit narrower bandgap...