Achieving intrinsically stretchable high-performance n-type polymer semiconductors via flexible linker engineering

Abstract

Herein, we developed two novel n-type intrinsically stretchable conjugated polymers, P1TVT and P2TVT, by incorporating non-conjugated 1,2-di(thiophen-2-yl) ethane (TET) or 5,5′-bis(2-(thiophen-2-yl) ethyl)-2,2′-bithiophene (di-TET) linkers into a diaza-benzodifurandione-based oligo(p-phenylene vinylene)-alt-(E)-1,2-di(thiophen-2-yl) ethene conjugated backbone. When evaluated in OFETs on polyethylene terephthalate (PET) substrates, the two polymers exhibited slightly reduced electron transport properties, with maximum electron mobilities (µ_e) of 0.51 cm² V⁻¹ s⁻¹ for P1TVT and 0.59 cm² V⁻¹ s⁻¹ for P2TVT, compared to 0.76 cm² V⁻¹ s⁻¹ for their fully conjugated counterpart, P0TVT. In stretchable OFET devices, P1TVT and P2TVT retained high µ_e values of 0.37 and 0.41 cm² V⁻¹ s⁻¹, respectively. Notably, P2TVT-based stretchable OFETs demonstrated better mechanical and electrical properties, maintaining µ_e values of 0.32 cm² V⁻¹ s⁻¹ under 25% parallel strain and 0.31 cm² V⁻¹ s⁻¹ under 25% vertical strain. This work highlights the effectiveness of flexible linker engineering as a design strategy for developing intrinsically stretchable high-performance polymer semiconductors.