Chemical Physics Seminar: New Insights into Complex Excited-State Phenomena from Predictive Computational Approaches
Dr. Sivan Refaely-Abramson, University of California, Berkeley, United States
In this talk I will discuss recent studies using new ab initio many-body perturbation theory methods to understand and uncover nanoscale energy conversion mechanisms. I will present a new approach to calculate multi-exciton generation processes in solids from first principles, used to study singlet fission in organic crystals. By applying this approach to crystalline pentacene, we recently discovered a new exciton—bi-exciton coupling channel, leading to new understanding of the role of symmetry and structure in the singlet fission mechanism in the solid state. Additionally, I will discuss recent research of excited state properties in monolayer transition metal dichalcogenides with point defects, where the defect states give rise to strongly-bound excitons and reduce the valley-selective circular dichroism, suggesting a pathway to tune spin-valley polarization and other optical properties through defect engineering. Finally, I will discuss future pathways to explore exciton transport mechanisms in various materials from first principles.
Seminar Organizers: Dr. Sharly Fleischer and Dr. Tal Schwartz