Structural Insights into Conjugated Polymers for Stretchable Organic Transistors

Stretchable electronics constitute a promising and innovative field, particularly in the development of fully stretchable transistors by using conjugated polymers (CPs). CPs have a unique thin-film microstructure with coexisting crystalline and amorphous regions, enabling a sophisticated balance between efficient charge transport and stretchable mechanical behavior. Despite recent advancements in polymer science, balancing these electrical and mechanical properties remains challenging. In this review, we discuss various aspects of the molecular, meso-, and macro-scale structural factors that affect the charge-transport behavior of CPs under stretching conditions. We begin this review with a brief introduction to polymer thin-film mechanics and related testing methods for obtaining the stress-strain relationship of CPs. Next, we introduce the morphological and structural aspects at various scales that affect stable charge transport under uniaxial tensile stretching. From a structural perspective, we also present strategies to improve the mechanical and electrical properties of CP thin films including blending functional additives, cross-linking the CP chains, and forming CP nanowire structures. Ongoing challenges and the outlook for this rapidly evolving field are also discussed. This review will provide valuable insights for readers interested in studying stretchable CPs with high electrical performance.