Engineering materials with light play a central role in modern science and technology. In this talk, I present my developed first-principles computational frameworks to model light–matter interactions across a broad range of energy transfer, quasiparticle excitations, and quantum states manipulation.

There had been a decades-long puzzle of understanding the nonradiative recombination mechanism in limiting the efficiency of wide-band-gap optoelectronic devices. I show my journey to solve the puzzle by developing a first-principles calculation formalism and code to calculate the rate of a trap-assisted Auger-Meitner (TAAM) process, to show that the TAAM process is the key mechanism to limit the efficiency in wide-band-gap semiconductor devices such as blue light-emitting diodes.

On the other hand, I show our idea to build a highly efficient deep-ultravioletphotoluminescence device by using a novel 3D moiré quantum well using hexagonal BN. I showed the mechanism of achieving high efficiency using accurate first-principles simulation of indirect excitons in the device. An exciton is a boson comprised of two fermions, and it has been widely treated as a boson, with its fermionic behavior at high densities often being neglected. I built a theoretical framework to explore the many-body correlations of excitons to reveal the regimes where we cannot treat excitons as bosons but as a composition of fermions. Finally, I show my computational design of a nanomaterial with tunable topology using external light field to manipulate localized quantum states.

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.