Simultaneous Enhancement in the Mechanical and Electrical Performance of Stretchable Polymer Semiconductor Blends via Miscibility Control

Achieving stretchable semiconductors with high carrier mobility, stretchability, and elastic recovery (ER) simultaneously remains challenging in the field of stretchable electronics. Herein, we demonstrate that increasing the polarity of flexible blocks in polyurethane matrices can reduce their miscibility with high-mobility conjugated polymer PDPPT3, promoting favorable phase separation in blend films for simultaneously improved fracture strain (εF), ER, and mobility. Blends based on a poly(tetramethylene oxide) block-containing matrix yielded moderate phase separation size to maintain top-level mechanical and electrical properties, with εF > 300%, ER = 88% at ε = 150%, and a high mobility of 3.35 cm2 V–1 s–1 for a blend with 25 wt % PDPPT3 and εF > 600%, ER = 93% at ε = 150%, and a mobility of 2.45 cm2 V–1 s–1 along with a long cycle life for 500 cycles of 200% strain for a blend with 10 wt % PDPPT3. Notably, the mobility of the blend was even enhanced by 2–3-fold by blending with a matrix containing polar flexible blocks as compared to neat PDPPT3.