Regensburg 2025 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 39: Poster III

HL 39.11: Poster

Wednesday, March 19, 2025, 15:00–18:00, P3

Implementation and Validation of a Herzberg-Teller Approach for Phonon-Assisted Photoluminescence — •Tobias Dittmann, Torben Steenbock, and Gabriel Bester — Insitut für physikalische Chemie, Universität Hamburg

Phonon-assisted PL from electronically excited states leads to the occurrence of phonon side-bands, which can shape the PL spectrum. A Franck-Condon framework based on Huang-Rhys factors efficiently describes phonon side-bands in nanostructures containing up to a few hundred atoms.[1] However, the FC approximation is usually not suited for the emission from a dark state. Therefore, we extend the method towards a Herzberg-Teller (HT) level which allows a more accurate description of the emission from a dark state. Additionally, our method includes the description of spin-orbit effects, offering an advantage over other implementations of the HT framework, particularly for structures containing heavy elements.

In a first stage of the project, we investigate various graphene quantum dots and observe that the inclusion of HT terms introduces both quantitative and qualitative differences compared to the FC spectrum. These findings underscore the critical importance of incorporating HT terms for accurate modelling. In future work, we intend to apply this method to bigger structures containing heavy elements, in order to benefit from the advantages of our implementation.

[1] Wu, Han, Dittmann, Wang, Zhang and Bester, Nanoscale, 2024, DOI: 10.1039/D4NR02458C

Keywords: phonons; Herzberg-Teller; photoluminescence