Low-Temperature Melt-Processable Polymer Semiconductors with Large-Ring Crown Ether Side Chains for High-Performance...

Polymer semiconductors are crucial components in organic electronics and have shown remarkable progress in recent years. However, their dependence on halogenated solvents for film processing raises environmental concerns and introduces risks of defects caused by residual solvent molecules during film drying. Melt processing has emerged as a sustainable alternative for fabricating polymer semiconductor films. Despite its potential, balancing low melting temperatures with high charge transport performance remains challenging, as high-performance polymers typically exhibit high melting points due to their rigid conjugated backbones. This study introduces a molecular design strategy incorporating large-ring crown ether (LCE) side chains to enhance the melt processability of conjugated polymers. This approach reduces the melt temperature to as low as 70 °C while maintaining excellent charge transport performance. Highly aligned polymer films are fabricated using melt friction transfer processing and employed in organic field-effect transistors (OFETs), achieving a carrier mobility of up to 1.06 cm² V^-1 s^-1 in the channel-parallel direction, approximately 2.5 times greater than their non-oriented counterparts. Aggregation structure characterizations reveal that these LCE side chains not only enable low melting temperature but also facilitate bimodal texture formation, creating 3D pathways for efficient charge transport. This strategy offers a scalable, eco-friendly approach to produce high-performance electronics.