All-polymer solar cells with efficiency approaching 16% enabled using a dithieno[3′,2′:3,4;2′′,3′′:5,6]benzo[1,2- c ][1,2,5]thiadiazole (fDTBT)-based polymer donor

Dithieno[3′,2′:3,4;2′′,3′′:5,6]benzo[1,2- c ][1,2,5]thiadiazole (fDTBT)-based polymer donors with tunable energy levels by sulfur/fluorine side-chains are designed and enable high-efficiency all-polymer solar cells with a maximum efficiency of 15.8%.