Robust Intrinsically Stretchable Organic Photodetectors Enabled by High-molecular-weight Conjugated Polymer Fibrils

Abstract

Intrinsically stretchable organic photodetectors (IS-OPDs) are highly attractive for applications such as skin-mounted wearables, soft robotics, and electronic textiles. However, simultaneously achieving mechanical robustness and stable optoelectronic functionality under high strain remains a challenge. Here, we demonstrate that the fibrillar network morphology formed by high-molecular-weight conjugated polymer blends provides an effective pathway to overcome this limitation. The entangled, interconnected polymer fibrils establish a mechanically percolated network that efficiently dissipates strain energy and suppresses crack propagation, enabling a high fracture strain of about 80% and enhanced toughness. The fibrillar network also forms continuous charge transport pathways, resulting in improved carrier mobility and reduced trap density. Therefore, the IS-OPDs exhibit outstanding performance stability under large deformations, maintaining a high detectivity of about 10¹² Jones at strains above 40%, while enabling reliable optical communication and clear imaging capability even at 100% strain. Our study identifies a high-molecular-weight-driven fibrillar morphology as a key structural motif for mechanically robust IS-OPDs.