Single-molecule time-resolved spectroscopy in a tunable STM nanocavity
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arXiv
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| Auteurs principaux: | , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866917578798006272 |
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| author | Doležal, Jiří Sagwal, Amandeep Ferreira, Rodrigo Cezar de Campos Švec, Martin |
| author_facet | Doležal, Jiří Sagwal, Amandeep Ferreira, Rodrigo Cezar de Campos Švec, Martin |
| contents | The 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 the tip and sample of 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 the coupling strength to the nanocavity. With this setup we estimate the excitation lifetimes from the direct time-resolved measurements of the fluorescence decays of phthalocyanine adsorbates, decoupled from the metal substrates by ultrathin NaCl layers. It is found that nanosecond-range lifetimes prevail for the emitters away from the nanocavity, whereas for the tip approached to a molecule, we find a substantial effect of the nanocavity coupling, which reduces the lifetimes to a few picoseconds. An analysis is performed to investigate the crossover between the far-field and tip-enhanced photoluminescence regimes. This approach overcomes the drawbacks associated with the estimation of lifetimes for single molecules from their respective emission linewidths. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2309_04416 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Single-molecule time-resolved spectroscopy in a tunable STM nanocavity Doležal, Jiří Sagwal, Amandeep Ferreira, Rodrigo Cezar de Campos Švec, Martin Mesoscale and Nanoscale Physics The 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 the tip and sample of 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 the coupling strength to the nanocavity. With this setup we estimate the excitation lifetimes from the direct time-resolved measurements of the fluorescence decays of phthalocyanine adsorbates, decoupled from the metal substrates by ultrathin NaCl layers. It is found that nanosecond-range lifetimes prevail for the emitters away from the nanocavity, whereas for the tip approached to a molecule, we find a substantial effect of the nanocavity coupling, which reduces the lifetimes to a few picoseconds. An analysis is performed to investigate the crossover between the far-field and tip-enhanced photoluminescence regimes. This approach overcomes the drawbacks associated with the estimation of lifetimes for single molecules from their respective emission linewidths. |
| title | Single-molecule time-resolved spectroscopy in a tunable STM nanocavity |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2309.04416 |