Understanding Exciton Transport Within Ordered Organic Assemblies from First-Principles Modeling

NONTECHNICAL ABSTRACT

This award supports computational research and education focused on understanding the interaction of light with ordered assemblies of carbon-based organic molecules, with the goal of realizing advanced solar energy conversion materials. Solar energy conversion refers to the process of harnessing solar energy and converting it to electricity or chemical energy, a promising technology for addressing the challenges associated with the projected future growth in energy needs.

This technology requires new materials, designed specifically to achieve more efficient and inexpensive solar energy conversion devices. In contrast to the traditional inorganic materials used in solar energy conversion devices, organic materials are abundant and extensively tunable by virtue of the mature field of synthetic organic chemistry. To utilize and improve these materials for solar energy conversion, it is necessary to understand their fundamental physical properties.

However, this understanding is hindered by the challenges in characterizing the behavior of atoms and electrons at nanometer length scales. By utilizing and developing upon state-of-the-art simulation methods, the PI and the research team will investigate the fundamental properties that govern the behavior of electrons within organic assemblies, in the presence of light, and develop physically intuitive models of the influence of molecular structure on electronic properties.

The ultimate result of this research will be to provide new design rules to efficiently convert solar energy within organic assemblies.

This project will integrate education and outreach with research in two ways. The PI will integrate the simulation methods developed in this research project into the graduate level course “Computational Materials Science”. Additionally, in collaboration with the Boston University Outreach and Diversity Program, the research team will deploy activity kits to museums across the world, introducing the scientific concepts to the broader community.

TECHNICAL ABSTRACT

This award supports computational studies aimed at understanding the behavior of optically excited states (excitons) in organic molecular assemblies. Organic materials are a highly tunable class of optically active materials that are promising as components in solar cells and photocatalysts. To make the use of organic materials in such applications feasible, we must develop an intuitive understanding of how to improve the efficiency and lifetime of the component materials.

The field of organic chemistry is mature enough such that molecular assemblies can be artificially constructed with a great degree of precision; however, there is still a lack of understanding regarding the design of these systems for efficient energy transfer, necessitating theory and computation to provide deeper physical intuition about their excited states. This project focuses on the role of long-range order on the optical properties of organic molecules in the condensed phase.

The PI and the research team will employ first-principles electronic structure theory to better understand how inter-molecular electronic and vibrational interactions modify the electronic structure and evolution of the excited-state within organic molecules in the solid state. The ultimate result of this research will be to provide new design rules to efficiently direct optical excitations along molecular assemblies.

This project will integrate education and outreach with research in two ways. The PI will integrate the simulation methods developed in this research project into the graduate level course “Computational Materials Science”. Additionally, in collaboration with the Boston University Outreach and Diversity Program, the research team will deploy activity kits to museums across the world, introducing the scientific concepts to the broader community.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.