Tuning Organic Semiconducting Binary Heterostructures Inherited by Template Nanostructures for Achieving High-Performance Organic Transistors

Abstract

The charge transport in organic semiconductors is unavoidably affected by morphological or crystalline structure resulting from the self-organized polycrystalline characteristics. To obtain the desired molecular arrangement in the heterostructured active layer, where nanostructures are gradually formed by piecing individual parts together into the final structures, it is necessary to formulate a precise strategy for anisotropic formation via weak epitaxy growth (WEG) of the layer structures. This strategy includes the nanostructural control of the bottom-templating layer through the inert character optimization of the supporting substrate surfaces. For these purposes, a copper phthalocyanine (CuPc) film grown on p-sexiphenyl (p-6P) as a bottom-templating layer is prepared to induce WEG between them, and supporting substrates are controlled using various inert self-assembled interlayers. The grain structures of the bottom-templating p-6P layer are dependent on the polar term of the surface energy in the variously modified supporting substrate, thereby inducing the activated WEG effect between the p-6P and CuPc semicrystalline structures. This strategy significantly improved the device performances of CuPc transistors (by a factor of up to 14). This result has important implications for optimizing a heterostructured active layer induced by the WEG mechanism and provides a solution for improving the device performance of organic electronics.