Semiconductors power almost every aspect of modern technology, from our mobile phones and computers, to how we light our homes, and how we store and transform energy from the sun into electricity. Understanding the complex quantum mechanical processes that make semiconductors such a fundamental resource for our modern world is a challenging task worth undertaking, because it promises to lead to a significant expansion of number and types of semiconductors society can use to address increasing demand. My research focuses on developing this understanding from a theoretical and computational perspective, using first principles methods to predict the photophysics of semiconductors starting from the basic laws of quantum mechanics, and without making use of empirical models.
In this talk, I will argue that excitons, quasiparticle generated by the absorption of photons in semiconductors, retain rich information about the Physics and Chemistry of heterogeneous semiconductors, and their systematic analysis has the potential to unlock novel chemical and physical intuition that can guide the design and discovery of new materials. I will start by introducing some basic concepts of Semiconductor Physics, including some simple textbook models for excitons, which are widely used in current literature. I will then show how first principles methods can be used to go beyond empirical modelling of excitons. Finally, I will give some examples from my research on metal-halide perovskites and show how chemical composition can impact the photophysics of excitons.