Robust Photo-Cross-Linked Polymer Semiconductors for Fully Stretchable and Photopatternable Electronics

Organic semiconductors are widely employed in flexible electronic devices due to their excellent solution processability. However, improving their mechanical properties often comes at the cost of diminished electrical performance. Here, we present a photochemical cross-linking strategy that simultaneously achieves high ductility and high charge carrier mobility. A benzophenone-capped polydimethylsiloxane (BP-PDMS) elastomer was synthesized as a photo-cross-linking agent and blended with a semicrystalline diketopyrrolopyrrole (DPP)-based polymer bearing siloxane side chains. Films with varying BP-PDMS content were cured under UV irradiation (365 nm, 30 mW cm–2), yielding mechanically robust, low-modulus networks. At polymer -to- cross-linker ratios of 10:1, 10:2, and 10:3, the films exhibited crack-free stretchability up to 100% strain. Notably, the charge carrier mobility parallel to the stretching direction exceeded 0.5 cm2 V–1 s–1 in the 10:2 and 10:3 films, surpassing that of the unstretched state due to strain-induced chain alignment. Fully stretchable transistor devices based on these cross-linked films demonstrated stable electrical performance under tensile deformation. Furthermore, the photo-cross-linked networks exhibited ∼80% retention of charge carrier mobility after 10 min solvent immersion and enabled precise photopatterning with minimum feature sizes of 13.6 μm. This work introduces an effective and scalable approach for designing organic semiconductors with combined mechanical resilience and high electronic performance, advancing the development of next-generation deformable electronic devices.