Photo‐Patternable Stretchable Semi‐Interpenetrating Polymer Semiconductor Network Using Thiol–Ene Chemistry for Field‐Effect Transistors

Abstract

Stretchable polymer semiconductors are an essential component for skin‐inspired electronics. However, the lack of scalable patterning capability of stretchable polymer semiconductors limits the development of stretchable electronics. To address this issue, photo‐curable stretchable polymer blends consisting of a high‐mobility donor–acceptor conjugated polymer and an elastic rubber through thiol–ene chemistry are developed. The thiol–ene reaction can selectively cross‐link the rubber with alkene or vinyl groups without damaging the electronic properties of the conjugated polymer. The conjugated polymer chains embedded in the elastic polymer matrix induce a semi‐interpenetrating polymer network (SIPN). The thiol–ene‐cross‐linked network provides great solvent resistance and enhances stretchability for the embedded conjugated polymer. The well‐defined patterned film with a feature size of ≈10 µm can be obtained using UV light at 365 nm through conventional photolithography processes. Furthermore, the SIPN‐based transistors show increased mobilities from 0.61 to 1.18 cm2 V−1 s−1 when applying the strain from 0% to 100%. Moreover, the hole mobility can still maintain at 0.87 cm2 V−1 s−1 after 1000 strain‐and‐release cycles at the strain of 25%. This study sheds light on the molecular design of photo‐curable polymer semiconductors for the mass production of stretchable circuits.

Nature-Inspired Semiconducting Polymers with Peptide Conjugation Breakers for Intrinsically Stretchable and Self-Healable Transistors

“…Researchers have incorporated elastomers, or cross-linkers, as additives. For instance, elastomers like polydimethylsiloxane (PDMS) and styrene–ethylene/butylene–styrene (SEBS), alongside covalent cross-linkers − with flexible additives, have proven to reduce long-range crystallinity. Furthermore, stacking OSCs with interfacial supporting layers, such as polyurethane and PDMS, has shown promise in delaying crack formation and propagation.…”

Chain-Kinked Design: Improving Stretchability of Polymer Semiconductors through Nonlinear Conjugated Linkers

“…Conjugated polymers have garnered significant interest for their potential in fabricating lightweight, flexible, and adaptable electronic devices. − Traditional design approaches for these polymers emphasize well-ordered crystalline morphology to minimize structural and energetic disorder and maximize π-orbital overlap between backbones. − However, designing stretchable polymer semiconductors calls for a more relaxed chain structure, increasing amorphous regions to dissipate strain energy. This necessity does not fully align with the traditional principles of polymer design. − To tackle these challenges, several techniques have been explored to adjust the structure of polymer semiconductors and enhance their stretchability.…”

Aligned Conjugated Polymer Nanofiber Networks in an Elastomer Matrix for High-Performance Printed Stretchable Electronics

“…Conjugated polymer films have emerged as the core semiconductors for next-generation wearable electronics, including artificial skin, smart sensors, and wearable high-energy radiation detectors due to its benefits in low-cost large-area printing, conformable geometry, and tunable optoelectronic properties. − For the application in wearable X-ray detectors or dosimeters, conjugated polymers can outperform the commercial semiconductors with the advantages of nontoxicity, tissue equivalency, light weight, and stretchability. − However, the conventional high-mobility conjugated polymer films are prone to fracture even at low strain, , which causes the catastrophic damage after stretching. To improve stretchability of conjugated polymer films, various strategies are used, including designing stretchable structures, , synthesizing polymers with soft building blocks, − and physically blending rigid conjugated polymers with deformable elastomers. ,− The latter provides a simple way to realize high-performance stretchable devices. For instance, Bao et al proposed the nanoconfinement effect to improve film ductility by increasing chain dynamics in a conjugated polymer:elastomer blend, which achieved a mobility of 1.32 cm 2 V –1 s –1 at 100% strain in an organic field effect transistor (OFET) .…”