Atom-Knotting Enables High-Performance Intrinsically Stretchable Polymer Semiconductors

Intrinsically stretchable polymer semiconductors are indispensable elements for the construction of stretchable electronic devices. Distinguished from incorporating flexible segments, developing the all-conjugated material system is expected to have great prospects. Herein, we propose the feasible atom-knotting strategy, with bridging atoms (N, C, S, and Si) partially inserted into donor units along regioregular conjugated polymer chains. The bending angle in the polymer backbone and the alkyl chain appended onto the bridging atom are central to mechanical stretchability. This strategy spawns a dual-mode stretchability enhancement mechanism. In addition to admittedly undermining film crystallinity (Mode I), bent chain conformations induced by atom-knotting could also promote bimodal stacking for preserved crystallinity and direct stretchability enhancement (Mode II). Si-knotted and S-knotted all-conjugated semiconducting polymers, initially 1.27 and 1.85 cm 2 V –1 s –1, respectively, exhibit superior carrier mobilities, performance retention, and cyclic stability in both stretching directions. Particularly, when subjected to 100% strain or cyclic stretching under 25% strain over 1000 cycles, both could maintain over 0.95 cm 2 V –1 s –1 along the stretching direction, far higher than that of the reference conjugated polymer. Originating from the structure–property relationship, the atom-knotting strategy provides a brand-new pathway to designing high-performance intrinsically stretchable polymer semiconductors.