Polymerizations of Diketopyrrolopyrrole-Type Dyes in Unconventional Orientation

Two diketopyrrolopyrrole (DPP)-derived monomers with extended π-conjugated skeletons are synthesized for polymerization in unconventional orientation. The π-conjugations in the monomers are either strengthened by resonance-assisted hydrogen bonds or by difluoroboron complexes. The pyrrolopyrrole aza-BODIPY-type monomer can be polymerized to give polymers with conjugated backbones completely different from any previously reported DPP-type polymers. The photophysical and electrochemical properties of the monomers and the polymers were studied. The semiconducting properties of the polymers were investigated in organic field-effect transistor devices. An average hole mobility of 0.10 cm2 V–1 s–1 has been achieved with one of the polymers. The results have demonstrated that DPP-type monomers can be polymerized in unconventional orientation to form polymers with interesting semiconducting properties.