Directing the Thin-Film Morphologies of Organic Semiconductors by Design

Semiconducting materials derived ?-conjugated organic molecules and polymers offer the promise of light-weight, flexible, embedded, and shock-resistant mobile electronics and power generation during Navy and Marine Corps operations. The design of novel materials, processing protocols, and device architectures have ushered tremendous advances in the development of organic electronics. Though progress is encouraging, there remains limited comprehensive understanding of the factors that collectively control semiconductor performance, a direct consequence of the tremendous dependence of device efficiencies on the active layer morphologies. Focusing on oligomer and polymer-based materials, we will harness the power of modern theoretical materials chemistry to generate a first-principles understanding of the impact of molecular and polymer chemical composition and architecture on the phase transformations that are critical to the formation of the hierarchal morphologies of organic semiconductors. Exploiting a multiscale computational approach comprised of state-of-the-art electronic-structure calculations and atomistic and coarse-grained molecular-dynamics simulations, we will characterize essential physicochemical processes that occur during the development of the morphology of organic semiconductor materials. A number of low-energy phases exist in these materials, and a detailed understanding as to how chemical composition and molecular architecture influence these phase minima can offer tremendous insight into the design of new molecular and polymer targets to control the thin-film morphology. Achieving our objective will yield the comprehensive, fundamental understanding of the dynamic molecular processes that take place during thin-film formation that will enable targeted, judicious materials designs to synthetically control the morphology of organic semiconductor layers. Tight feedback loops developed through this program with materials, experimental, and device researchers at various stages along the technology pipeline will inform our models and ensure the translation of the theoretical results towards materials and device designs that aim to control the extrinsic characteristics of these materials. Performance Period: July 1, 2016 to June 30, 2018 Total Funds Requested: $220,000