IBM-Illinois Discovery Accelerator Institute

Abstract

Understanding and controlling quantum processes in molecular materials is central to next-generation optoelectronics and energy technologies. In organic semiconductors, exciton formation, charge separation, and charge transport are governed by strongly coupled electronic and vibrational degrees of freedom, requiring scalable quantum-mechanical approaches that bridge first-principles electronic structure and many-body dynamics. In this talk, I present recent advances in such methods for excitonic and charge transport processes. I first introduce the Linear-Scaling Wannier Optics (LSWO) framework, which enables efficient ab initio calculations of optical absorption in large, structurally complex systems by combining localized Wannier representations with excitonic Hamiltonians [1]. I then discuss fully quantum treatments of non-adiabatic exciton dynamics using tensor-network techniques based on Matrix Product States (MPS) and multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) [2]. These approaches provide controlled benchmarks and reveal the central role of electronic–vibrational entanglement in exciton dissociation. Finally, I address quantum-informed modeling of charge transport by integrating electronic-structure theory with crystal structure prediction, enabling mobility estimates even in the absence of experimental crystal data [3]. Together, these developments demonstrate how advanced quantum simulation frameworks enable predictive modeling and rational design of organic optoelectronic materials.

References

[1] K. Merkel and F. Ortmann, J. Phys. Mater. 7, 015001 (2024).
[2] M. F. X. Dorfner, D. Brey, I. Burghardt, and F. Ortmann, J. Chem. Theory Comput. 20, 8767 (2024).
[3] S. Hutsch, M. Panhans, and F. Ortmann, npj Comput. Mater. 8, 228 (2022).