Ternary PM6:Y6 Solar Cells with Single‐Walled Carbon Nanotubes

An organic solar cell with single‐walled carbon nanotubes (SWCNTs) in the photoactive layer is typically a type II heterojunction with the semiconducting SWCNTs acting as the electron donor and C 60 or other fullerene derivatives as the acceptor. Herein, the performance of solar cells consisting of (6,5) SWCNTs combined with C 60 and three nonfullerene acceptors is evaluated in a bilayer architecture. SWCNTs are then combined with the donor/acceptor PM6:Y6 in a ternary mixture and both bulk heterojunction and bilayer devices are fabricated. The SWCNTs are found to extend the light absorption of PM6:Y6 solar cells into the infrared but their use must strike a balance between the SWCNT concentration to enhance light absorption and solvent‐induced changes to the morphology of the active layer.