Synthesis, characterization, and their field-effect properties of azaisoindigo-based conjugated polymers with versatile alkoxycarbonyl substituents

In this study, versatile alkoxycarbonyl substituents were incorporated onto the azaisoindigo (AIID)-based polymeric pi-skeleton, affording two novel polymers PAZPT and PAZPTEt. The PAZPT has the alkoxycarbonyl groups substituted on its thiophene unit, whereas the PAZPTEt has both the thiophene and thieno [3,2-b] thiophene units substituted with alkoxycarbonyl groups. As result, PAZPT has more planar conjugated backbone conformation than that of PAZPTEt. Experimental characterization results indicated that alkoxycarbonyl substituents can effectively pull down the frontier molecular orbital energy levels and optimize the solubility and molecular packing mode of conjugated polymers. All the field-effect transistors based on the two polymers showed ambipolar carrier transport characteristics. Such results show that introducing alkoxycarbonyl substituents on polymeric pi-skeleton might be a potential approach in fine-tuning the semiconducting properties of conjugated polymers.

Automated summary

This study introduced versatile alkoxycarbonyl substituents onto the azaisoindigo-based polymeric pi-skeleton, leading to the synthesis of two novel polymers. Experimental results showed that alkoxycarbonyl substituents can effectively modulate the properties of conjugated polymers, enhancing solubility and optimizing molecular packing. All field-effect transistors based on these polymers exhibited ambipolar carrier transport characteristics, indicating the potential of alkoxycarbonyl substituents in fine-tuning the semiconducting properties of conjugated polymers.