The correlation between the geometrical structural change in push-pull π-conjugated polymers and the formation of phase segregation in their bulk heterojunction (BHJ) composite films is investigated. When substituted with large alkyl side chains, the polymer wires experience serious conformational distortion by increasing the torsion energy of dihedral angles along the backbone and undergo large-scale phase segregation in the BHJ composites.
- bulk heterojunction composites
- phase segregation
- polymer solar cells
- push-pull π-conjugated polymers
- torsion energy