Polymer semiconductor blends with remarkably stable semiconducting performance under large and cyclic mechanical deformation

In this paper, we report deformable blend thin films of polymer semiconductors with PDPPTT (p-type) and N2200 (n-type) as the examples by using the hydrogenated polyisoprene (H-PIP) as the newly developed elastomer. As compared to the respective blends with other elastomers, the blends with H-PIP bear lower elastic moduli and higher crack on-set strains, and in particular exhibit remarkably stable semiconducting performance under large and cyclic mechanical deformations. This aligns with the observation that the assembly structures of polymer semiconductors are stable within the H-PIP matrix based on AFM and GIWAXS characterizations. This exceptional performance is attributed to the unique structure of H-PIP, which is solely composed of mobile aliphatic-hydrocarbon chains without chemical/physical crosslinks. This enables the blend thin films with H-PIP to follow the mechanical deformations of the substrate without generating internal stress and affecting the interconnected assembly networks of the polymer semiconductor, thus leading to stable semiconducting performance. Designing organic semiconductors for ductility and charge transport properties is a challenge. Here, the authors report a family of deformable high performance polymer semiconductor blends using hydrogenated polyisoprene.