Controlling Solution-Phase Polymer Aggregation with Molecular Weight and Solvent Additives to Optimize Polymer-Fullerene Bulk Heterojunction Solar Cells

The bulk heterojunction (BHJ) solar cell performance of many polymers depends on the polymer molecular weight ( M n ) and the solvent additive(s) used for solution processing. However, the mechanism that causes these dependencies is not well understood. This work determines how M n and solvent additives affect the performance of BHJ solar cells made with the polymer poly(di(2‐ethylhexyloxy)benzo[1,2‐ b :4,5‐ b ′]dithiophene‐ co ‐octylthieno[3,4‐...