Stretchable Fully π‐Conjugated Polymer Films via Dual‐Functional Fluid Semiconductor Supramolecular Polymer Plasticizing for Flexible Light‐emitting Diodes

ABSTRACT Emerging stretchable fully π‐conjugated polymers (FπCPs) films are promising functional layers in flexible optoelectronic devices. However, simultaneous enhancement of the stretchability and optoelectronic properties of FπCPs films via traditional chain‐softness modification or physical blending approaches is challenging due to the inherently weak interchain charge‐transportation and morphological stability of these films, hindering their wide application in flexible electronics. Herein, we establish a new semiconductor supramolecular polymer (SSP) plasticizing strategy to simultaneously enhance the optoelectronic, morphological, and stretchable properties of FπCPs films for flexible polymer light‐emitting diodes (PLEDs). Two fundamental requirements were proposed—fluid monomer (EODBC) to obtain plasticizing and supramolecular π‐conjugated monomer (FMIPF6) to achieve excellent optoelectronic characteristics—to prepare model‐matched SSP plasticizers (EODBC‐FMIPF6). Interestingly, F8BT blending films present a uniform morphology with efficient emission. Therefore, the stretchability and charge transport behavior of FπCPs films can be improved simultaneously via SSP plasticization due to the synergistic effect of hierarchical structure and optoelectronic properties of SSP plasticizers, increasing the external quantum efficiency of PLEDs by approximately 13%. Finally, flexible PLEDs based on stretchable F8BT blending films were fabricated to confirm the effectiveness of our strategy. Our results show that dual‐functional fluid SSP may be used as novel plasticizers to manufacture stretchable FπCPs for flexible electronics.