2,1,3-Benzothiadiazole-5,6-Dicarboxylic Imide - A Versatile Building Block for Additive-and Annealing-Free Processing of Organic Solar Cells with Effi ciencies Exceeding 8%

A new photoactive polymer comprising benzo[1,2‐b:3,4‐b′:5,6‐d′]trithiophene and 2,1,3‐benzothiadiazole‐5,6‐dicarboxylic imide is reported. The synthetic design allows for alkyl chains to be introduced on both electron‐rich and electron‐deficient components, which in turn allows for rapid optimization of the alkyl chain substitution pattern. Consequently, the optimized polymer shows a maximum efficiency of 8.3% in organic photovoltaic devices processed in a commercially viable fashion without solvent additives, annealing, or device engineering