Spatial Distribution Regulated Chemical Doping toward High-Performance Stretchable Conjugated Polymer Films

Chemical doping has emerged as a promising strategy for fabricating high-performance stretchable conjugated polymer films. However, the underlying working mechanisms remain poorly understood. Herein, by a combination of theory simulation and structural characterization, we demonstrate that the spatial distribution of chemical dopants in conjugated polymer films is critical for simultaneously enhancing the carrier mobility and stretchability of the films. Using the conjugated polymer poly(indacenodithiophene-co-benzothiadiazole) (IDTBT) and the dopant tris(4-bromophenyl) ammoniumyl hexachloroantimonate (Magic Blue, MB) as a model, we demonstrate that the intimate contact between MB and the IDTBT backbone promotes the efficient charge transfer via cation-π interactions. It not only induces a more planarized backbone with enhanced charge delocalization but also introduces structural disorder with enlarged π–π stacking distance. The former improves intrachain charge transport and reduces contact resistance in transistor devices, whereas the latter enables effective strain energy dissipation through chain sliding and alignment during stretching. Consequently, the IDTBT film exhibits ca. a 2-fold increase in both carrier mobility and fracture strain through chemical doping. Moreover, the doped film maintains a high mobility of 1.85 cm2 V–1 s–1 at 100% strain, significantly outperforming the pristine film (ca. 0.18 cm2 V–1 s–1 at 100% strain). This work provides a guideline for the chemical doping regulation to construct high-performance stretchable conjugated polymer films.