Treating Poly(3-hexylthiophene) with Dimethylsulfate Improves Its Photoelectrical Properties

Poly(3-hexylthiophene) is reacted with the methylating agent dimethylsulfate. This increases the hole mobility, almost doubles the exciton diffusion length, and substantially enhances the photochemical stability of the polymer in air. The reaction may involve neutralization of anionic defects via addition of a methyl cation to the polymer backbone.