Fig. 4: Contact angles and morphologies.

a Contact angles of PM6, PY-IT, PY-IT2F, PG-IT, and PG-IT2F and the corresponding Flory-Huggins interaction parameters. b AFM height images and TEM images of PM6:PY-IT2F, PM6:PG-IT, and PM6:PG-IT2F blend film. c Schematic diagram of the morphology of PM6:PY-IT2F and PM6:PG-IT2F blend film.