Understanding how light interacts with matter at the atomic scale is central to emerging energy and quantum technologies. A key concept in this context is the exciton—a bound electron-hole pair created when a material absorbs light—which governs many of the optical properties of semiconductors.

Most theoretical work to date has focused on excitons at the moment of their creation, characterizing properties such as their binding energy and size. Much less is known about what happens afterward: how excitons move, interact with their environment, and ultimately decay. Describing such processes with atomistic detail requires new theoretical tools.

In this talk, I will present recent theoretical advances and first-principles simulations that address exciton dynamics in emerging energy materials. In the first part of my talk, I will discuss how lattice vibrations (phonons) couple to excitons, shaping their lifetimes and optical spectra, with examples from two-dimensional transition metal dichalcogenides.

I will then introduce our discovery of maximally localized exciton Wannier functions, a new and intuitive way to represent excitons that offers a fresh perspective on their behavior. As an application, I will show how these functions can be used as an efficient basis for describing exciton transport in organic semiconductors—materials that are challenging to model due to their many competing energy scales.

I will conclude by outlining how these methods open new opportunities for understanding and controlling light–matter interactions in energy and quantum materials.

Before the talk (~3:45pm), tea and coffee will be served outside 149 Weniger.

After the talk, there will be a reception with food and drink in 247 Weniger.