Optical measurements of single molecules and their clusters

CIC nanoGUNE Seminars

Martin Svec
Institute of Physics, Czech Academy of Sciences
CIC nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
Niklas Friedrich
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Optical measurements of single molecules and their clusters

Exploration of essential photophysics at the level of individual molecules and atoms requires highly specialized optical spectroscopies that work at the very limit of instrument sensitivity or have to use plasmonic nanostructures - in order to overcome the fundamental resolution limits achievable with visible and infrared light. Recently pioneering electroluminescence (EL), photoluminescence (PL) and tip-enhanced Raman spectroscopies have been demonstrated using the Scanning Probe Microscopy (SPM) platform at liquid He temperatures, a technique especially well suited for investigation of molecules, atoms and their assemblies. Implementation of the optical methodology opened a window of opportunity to pursue intriguing, often hard-to-access interactions between the light and matter, characterize excitation eigenmodes, charges, vibronics and temporal evolution of transient states with tremendous accuracy. The addition of the toolbox of STM, STS and AFM provide reliable support in questions of the system geometry and electronic configuration. First, we applied this combined methodology to investigate fundamental properties of the PTCDA molecules and their aggregates in the excited state, addressing exciton delocalization by EL [1] and PL in the real space. Next we formed a break junction with the PTCDA anion and investigated a correlation between its resonant Raman spectra and the appearance of a Kondo resonance in the STS.[2] Finally, we have studied the lifetime of an exciton of phthalocyanine molecule as a function of nanocavity size with picosecond time-resolved measurements.[3]


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[1] ACS Nano 16, 1082-1088 (2022)

[2] arXiv:2310.12546, 2023

[3] arXiv:2309.04416, 2023