Single-Molecule Time-Resolved Spectroscopy in a Tunable STM Nanocavity.

0582874 - ÚOCHB 2025 RIV US eng J - Journal Article
Doležal, J. - Sagwal, A. - de Campos Ferreira, R. C. - Švec, Martin
Single-Molecule Time-Resolved Spectroscopy in a Tunable STM Nanocavity.
Nano Letters. Roč. 24, č. 5 (2024), s. 1629-1634. ISSN 1530-6984. E-ISSN 1530-6992
Institutional support: RVO:61388963
Keywords : TEPL * STM * photoluminescence * nanocavity * TCSPC * phthalocyanine
OECD category: Physical chemistry
Impact factor: 10.8, year: 2022
Method of publishing: Open access
https://doi.org/10.1021/acs.nanolett.3c04314

Spontaneous fluorescence rates of single-molecule emitters are typically on the order of nanoseconds. However, coupling them with plasmonic nanostructures can substantially increase their fluorescence yields. The confinement between a tip and sample in a scanning tunneling microscope creates a tunable nanocavity, an ideal platform for exploring the yields and excitation decay rates of single-molecule emitters, depending on their coupling strength to the nanocavity. With such a setup, we determine the excitation lifetimes from the direct time-resolved measurements of phthalocyanine fluorescence decays, decoupled from the metal substrates by ultrathin NaCl layers. We find that when the tip is approached to single molecules, their lifetimes are reduced to the picosecond range due to the effect of coupling with the tip-sample nanocavity. On the other hand, ensembles of the adsorbed molecules measured without the nanocavity manifest nanosecond-range lifetimes. This approach overcomes the drawbacks associated with the estimation of lifetimes for single molecules from their respective emission line widths.
Permanent Link: https://hdl.handle.net/11104/0350919