Exciton Dynamics in Functional Materials: New Theoretical Frontiers
On-line, hosted by CECAM-HQ-EPFL
*** We thank all participants for an enriching and stimulating workshop! Hope to meet again soon. ***
Electronic and optical interactions dominate emerging applications, including optimizing solar energy conversion and storage, producing tunable light-emitting diodes, designing photon emitters for quantum information science, and more. The involved processes typically include energetically-excited states, and in particular, neutral or charged energy carriers called excitons, composed of excited electrons and holes, bound together through Coulomb interaction. The exciton relaxation, scattering, and decay dynamics, as well as their ballistic and diffusive transport, are key ingredients in device functionality and are closely related to the atomic composition of the materials and the selection rules resulting from it. Understanding the relation between material structure and excited-state properties as well as their dynamics is hence of great interest. It can introduce design pathways to control and tune underlying interaction mechanisms in broad areas of photophysics.
In recent years, extensive experimental research is dedicated to studying time-resolved excited-state phenomena in solid-state functional materials, such as monolayer transition metal dichalcogenides (TMDCs), organic molecular crystals, organic-inorganic hybrids, quantum dot solids, and metal-organic complexes. Such systems often host strongly-bound excitons as energy carriers, typically with exciton binding energies of tens to many hundreds of meV. Advanced time-resolved spectroscopy and microscopy experiments suggest that those excitons can exhibit a rich variety of dynamics due to a number of complex phenomena. These include nonradiative multi-exciton generation in organic crystals, Auger recombination and exciton-exciton annihilation in 2D materials, and the decay of bright excitons into low-lying dark states constrained by momentum in valley-selective monolayers or quantum dots. Complex interaction processes are further shown to have strong coupling to phonons and structural inhomogeneities, such as atomic defects, local strain, or environmental screening.
The goal of this workshop is to bring together researchers from different scientific communities, who study time-resolved exciton phenomena in functional materials using a broad variety of approaches. While the main focus of the workshop is computational developments, an important aspect of it is a state-of-the-art experimental perspective. Within a joint cross-community computational-experimental meeting, we wish to encourage exchange of ideas and identify emerging questions for future research directions and collaborations, as well as to share and advance current theoretical methods to exciton dynamics and transport in functional materials.
Alexey Chernikov (TU Dresden) - Organiser & speaker
Angel Rubio (Max Planck Institute for the Structure and Dynamics of Matter) - Organiser & speaker
Sivan Refaely-Abramson (Weizmann Institute of Science) - Organiser & speaker
Timothy Berkelbach (Columbia University) - Organiser & speaker
Felipe H. da Jornada (Stanford University) - Organiser & speaker
Archana Raja (Lawrence Berkeley National Lab) - Organiser & speaker