We are glad to present a new seminar at the ICMM:
TITLE: The fundamental effect of the atomic-scale environment on the photophysics of single (bio)molecules
AUTHOR: Daniel Arribas, Max Planck Institute for Solid State Research of Stuttgart, (Germany).
INVITED BY: Pablo Merino
LUGAR: Sala de Seminarios del ICMM, 12h.
ABSTRACT: As one of the main biomolecules harvesting light in photosynthetic organisms, chlorophyll plays a crucial role in biological systems, ultimately sustaining life on Earth. However, its role in photosynthesis is far from simple, as its optical properties are tuned by a subtle interplay between each single chlorophyll molecule and other pigments and biomolecules present in its local environment. Depending on its context, this results in several possible functions for each molecule, for example, light harvesting, exciton transfer, energy dissipation, or acting as an electron donor/acceptor.
Understanding this rich photophysics requires addressing the molecules with sub-nm resolution. However, the optical characterization of individual molecules finds a fundamental obstacle in conventional diffraction-limited spectroscopies, which probe ensembles of molecules, obscuring the effects of individual molecule configuration and the local environment. In this regard, the combination of scanning tunneling microscopy with optical detection and excitation has emerged as a powerful methodology for probing light-matter interaction at the atomic scale on model single-molecule systems [1], profiting from the highly-localised plasmonic enhancement of the picocavity at the tunnelling junction.
In this talk I will present our most recent contributions to the field of single-molecule light-matter interaction, systematically investigating the local environment on model phthalocyanine emitters [2] in donor-acceptor configurations on insulating NaCl layers on Ag(111) and its effects on the fluorescence of single emitters. In addition, I will present our first optical characterization of chlorophyll molecules at the sub-nanometer scale, including its electroluminescence, tip-enhanced photoluminescence and tip-enhanced Raman spectroscopy, providing an initial step towards our fundamental understanding of more complex supramolecular aggregates.
References
[1] A. Rosławska et al., Tip-enhanced molecular fluorescence microscopy with atomic-scale resolution, Reviews of Modern Physics 98, 2026, DOI: 10.1103/pqvw-kv92
[2] T. G. L. Brito, D. Arribas, S. Canola, K. Kuhnke, T. Neuman, A. Rosławska, Tuning single-molecule fluorescence by atomic-scale control of the local environment, arXiv:2608.16826
