High-adhesion stretchable organic single-crystal photoelectric thin films.

Endowing single-crystal films with stretchability is crucial for their application in wearable devices, allowing for conformal integration with dynamically strained biological tissues. While organic crystalline photosensitive semiconductors hold significant potential in artificial eyes, photodetectors and neuromorphic vision, their inherent trade-off between crystallinity and mechanical compliance impedes stretchable implementations. Herein, we demonstrate a scalable method for directly growing omnidirectionally stretchable photoresponsive organic single-crystal films (OCFs) on elastic substrates, with high interfacial adhesion. The resulting OCFs nucleate within and grow outward from the polydimethylsiloxane (PDMS) substrate, forming a cobweb-like network morphology with embedded roots anchoring onto the substrate, mirroring plant anchorage in soil. The substrate confinement effect ensures robust adhesion with a strength of 0.8 MPa, triple that of samples without root-embedded structures, while the network expansion/contraction mechanism maintains structural integrity during large tensile strains (up to 20%) in multiple directions. The resulting stretchable photodetector exhibits invariant functionality under dynamic deformation, enabling reliable light sensing in complex stretching scenarios.