Nature exquisitely controls the spatial arrangement of key pigments and dyes in the process of photosynthesis to harness solar energy. Mimicry of controlled dye arrangements in synthetic materials can be realized through tailored design of molecules and molecular arrangements. However, exerting reliable control over the assembly of engineered molecular materials in the crucial 10-100 nanometer "mesoscale" regime, thousands of times smaller than a millimeter, remains elusive. Such mesoscale molecular structures will combine charge and energy transfer activities with capabilities for assembly in biological solutions, and compatibility with biological environments. Given the multitude of molecular design possibilities, it is essential that experimental programs incorporate computer modeling and data-driven screening to guide experimental design and synthesis. Tight integration and mutually reinforcing feedback between computation and experiment can reveal fundamental design rules for molecular assembly, and accelerate the discovery and development of multi-molecule assemblies with tailored structure and function. This project will develop these functional molecular superstructures in a collaboration encompassing molecular synthesis, self-assembly analogous to biological systems, modeling of the structures and electrical properties of the assemblies, and utilizing the assemblies to manage interactions between light and electricity. The PIs are committed to workforce training and development within this project, guiding the next generation of materials and data scientists of diverse socio-economic background in state-of-the-art tools and exposing them to an integrated interdisciplinary mode of work that will define future research.
photophysical and electrical properties of pi-conjugated supramolecular systems depend critically on the explicit nature of the intermolecular electronic interactions. These interactions are governed by the precise molecular structure and chemistry and emergent supramolecular arrangements. The PIs developed a peptide construct that offer a pathway to exert such control over emergent supramolecular structure through tailoring of steric bulk and variable hydrophobicity of the component sequences to influence intermolecular orientations, higher-order fibrilization, and specific electronic outcomes. They initially used an Edisonian approach to uncover these variations, but the goals of this project are to wield explicit engineered control through tightly integrated atomistic simulations and electronic structure calculations. The research activities build upon the team?s strong foundation to accomplish these goals in two specific objectives: (i) the development of sophisticated peptidic semiconductor materials with advanced optoelectronic functionality and (ii) the development of new assembly paradigms leading to heterogeneous peptidic nanomaterials with chemical and electronic gradients and localized electric fields. The execution of this work will entail interconnected efforts by the research team in the (i) synthesis of new pi-electron units and new self-assembling peptides, (ii) molecular and data-driven modeling of the nanomaterial aggregates and their higher-order assemblies, and (iii) characterization of electrical transport within the nanomaterials. This project will make special provision for research opportunities for undergraduate students, women, and underrepresented minorities. The PIs will train and mentor researchers in state-of-the-art experimental and computational tools and expose them to an integrated interdisciplinary mode of work. K-12 outreach activities will inspire excitement and awareness of materials science and encourage students to pursue higher education in science, technology, engineering, and math (STEM) fields.