Near-Amorphous Conjugated Polymers: An Emerging Class of Semiconductors for Flexible Electronics

Abstract

The emergence of flexible electronics with broad application prospects has put forward new requirements for organic semiconductors, i.e., not only the electrical properties but also the mechanical properties. Among the strategies to achieve synergy between mechanical and electrical properties, near-amorphous polymers are competitive candidates due to their advantages of intrinsic flexibility, high mobility, and high reproducibility. Near-amorphous polymers with excellent performance are continuing to attract attention, and recently, some significant progress has been achieved in this field. In this perspective, we summarize these excellent advances on near-amorphous polymers from the point of view of their molecular design principles, their resulting charge transport and mechanical properties, and their potential applications in flexible electronic devices. Finally, we give a brief discussion on the challenges and opportunities of nearamorphous materials in flexible electronics from the perspectives of semiconductor layer materials themselves, devices, and multifunctional integration.

Recent advances in n-type and ambipolar organic semiconductors and their multi-functional applications

“…Moreover, the aggregation state of the materials, such as an amorphous state, a semi-crystalline state and a single crystal state, plays an important role in the fabrication of final high-performance or multi-functional devices. [394][395][396][397] To obtain efficient charge transport properties, materials are always designed and assembled with highly ordered stacking structures and low defect density. In particular, organic semiconductor single crystals with long range order have always been considered as the best platforms to achieve high carrier transport performance, irrespective of whether they are n-type, ambipolar or p-type organic semiconductors.…”

Intrinsically Stretchable Block Copolymer Composed of Polyisobutene and Naphthalenediimide–Bithiophene-Based π-Conjugated Polymer Segments for Field-Effect Transistors

“…At 0% strain, the μ e for the ABA100, ABA85, and ABA52 polymers is determined to be 0.012, 0.043, and 0.0032 cm 2 V −1 s −1 , respectively. At 100% strain, the μ e retention rates for ABA100, ABA85, and ABA52 are (30,17), (14,18), and (46, 57)% with strains applied parallel/perpendicular to the channel direction, respectively. ABA100 and ABA85 exhibit similar performance decay; in contrast, ABA52 possesses much improved μ e retention due to a high PIB content.…”

“…Therefore, structural engineering of semiconducting polymers is regarded as a favorable approach for practical applications. For example, PNDI2Ts with molecular weight engineering, random terpolymerization with similar conjugated moieties , or conjugation break spacers (CBSs), − and near-amorphous structures − have been recently developed. Our group has developed PNDI2Ts with ester-based CBS that produce mobility retentions of 37 and 40% under a strain of 60% and after 400 stretch–release cycles at 60% strain .…”

Air/Liquid Interfacial Self-Assembled Intrinsically Stretchable IDT-BT Film Combining a Deliberate Transfer Adherence Strategy for Stretchable Electronics

“…Intrinsically stretchable transistors, which are made of low-modulus all-stretchable electronic components, can be seamlessly integrated with human skin and maintain the normal operation with moving and deformation of human skin, present outstanding advantages in high-comfort wearability, good biocompatibility, and high mechanical robustness for future stretchable electronics. – However, stretchable semiconductors, as the core and fundamental components of intrinsically stretchable transistors, have significantly held back the development of intrinsically stretchable transistors because of the limited available materials. ,– Most of organic and inorganic materials are still too brittle and present the low crack-onset strain lower than 10% . The available intrinsically stretchable semiconductors are mainly limited in indacenodithiophene-benzothiadiazole (IDT-BT) and diketopyrrolopyrrole-based polymers.…”