High-performance n-type stretchable OFETs enabled by molecular engineering of flexible polymers†

Abstract

Stretchable organic field-effect transistors (OFETs) have emerged as promising semiconductor devices for flexible electronics, combining mechanical deformability with stable electrical performance. However, developing high-performance n-type stretchable semiconductors remains challenging. In this study, we designed three novel n-type polymers (P1–P3) by incorporating flexible chains into an azo-benzodifurandione-based oligo(p-phenylene vinylene) (azo-BDOPV) backbone, achieving balanced mechanical and electrical properties. Using polydimethylsiloxane substrates, gold and silver nanowire electrodes, and polyvinyl alcohol (PVA) dielectric layers, we fabricated fully stretchable top-gate n-type OFETs. The devices demonstrated excellent initial electron mobilities of 0.44, 0.34, and 0.52 cm² V⁻¹ s⁻¹ for P1–P3 respectively, with P3 showing superior performance. Remarkably, P3 maintained mobilities of 0.48–0.29 cm² V⁻¹ s⁻¹ (strain parallel to the charge transport direction) and 0.42–0.26 cm² V⁻¹ s⁻¹ (strain perpendicular to the charge transport direction) under 15–50% deformation, demonstrating exceptional mechanical–electrical stability. All three polymer films show uniform surface morphology and molecular stacking, with polymer P3 having the most ordered edge-on stacking, which is consistent with its excellent device performance. These results highlight the effectiveness of molecular engineering in developing stretchable n-type semiconductors with mechanical flexibility and efficient charge transport, providing valuable insights for the design and application of high-performance fully stretchable OFETs, advancing the development of next-generation flexible and wearable electronics.