Aqueous-Alcohol-Processable High-Mobility Semiconducting Copolymers with Engineered Oligo(ethylene glycol) Side Chains

Replacement of toxic chlorinated solvents with eco- and human-friendly solvents is an important task for the successful implemention of next-generation polymer electronics technology. Herein, we designed and synthesized five aqueous-alcohol-processable conjugated copolymers by incorporating linear or branched oligo(ethylene glycol) side chains and systematically investigated their material and electronic properties. The resulting benzothiadiazole-based donor–acceptor alternating copolymers were well-soluble in both an ethanol/water mixed solvent and a chlorinated solvent, and their thin films showed distinct morphologies and crystalline characteristics that resulted from the self-assembling properties of the engineered side chains. Moreover, the copolymers showed excellent electrical characteristics with high hole mobilities of up to 0.1 cm2 V–1 s–1, which is among the highest values reported thus far for polymer field-effect transistors processed using truly eco- and human-friendly solvents without the use of any surfactants. These results clearly demonstrate the immense potential of branched oligo(ethylene glycol) side chains for application in green electronics.