Sustainable Aqueous Emulsification of Polymer Semiconductors for Ecofriendly, Streamlined Organic Electronics

Abstract

Polymer semiconductors (PSCs) have attracted significant attention as promising alternatives to conventional silicon-based semiconductors owing to their low cost and solution processability. However, the use of hazardous organic and halogenated solvents in organic field-effect transistor (OFET) processes has raised significant concerns regarding severe environmental issues. To address these issues, the ecofriendly solution processes for PSCs utilizing water as a solvent are proposed, in which PSCs are emulsified in aqueous media with ionic surfactants. However, these emulsified processes, which rely on surfactants, necessitate complex additional steps (precipitation and redispersion) to ensure their complete removal. Herein, PSC is successfully emulsified using the relatively volatile, nonionic benzyl alcohol (BA) as a stabilizer and it is confirmed that BA is completely removed from the PSC film during the thermal annealing conducted to enhance its crystallization. Consequently, OFETs, with this approach, demonstrate device characteristics comparable to those using organic solvent-based methods. Additionally, the successful implementation of logic circuits, such as inverters and NAND/NOR gates, is validated through printed electronics processes employing emulsified PSC aqueous solutions. The results suggest sustainable methodology through the implementation of an aqueous emulsification strategy, highlighting its potential as an environmentally friendly manufacturing approach in the field of organic electronics.