Narrow-bandgap acceptors with low energetic disorder achieve over 21% efficiency in organic solar cells

Narrow-bandgap acceptors with minimal energy loss and high short-circuit current density for organic solar cells are rare. Here a designed acceptor incorporated into ternary blends achieves low energy loss of 0.486 eV and high short-circuit current density of 28.82 mA cm−2, resulting in a 21.12% certified efficiency in organic solar cells.