Nonhalogenated-Solvent-Processed Efficient Polymer Solar Cells Enabled by Medium-Band-Gap A−π–D−π–A Small-Molecule Acceptors Based on a 6,12-Dihydro-diindolo[1,2-b:10,20-e]pyrazine Unit
A new nonfullerene electron acceptor of m-MeIC was designed and synthesized, which is effective with different band-gap polymer donors, including wide band-gap J71, medium band-gap PBDB-T and low band-gap PCE-10.