1MoleculeNearPlasmon · Single-molecule spectroscopy in the near field of plasmonic metal nanoparticles
FP7 — People (Marie Curie Actions)
- Duration
- 2012-04-01 → 2014-03-31
- EU contribution
- €183,806
- Participants
- 1
- Scheme
- MC-IEF
Lines connect the coordinator with its partners.
Results in brief
Single-molecule spectroscopy in the near field of plasmonic metal nanoparticles
The project aimed at observing modification in coupling of a plasmonic antenna to single molecules in a solid at cryogenic temperatures. This is a difficult experiment that has not been achieved yet because it requires control of the nano-environment of the antenna in a cryostat at liquid-helium temperature. The unique advantages of this experiments, though are: 1. the coupling of the molecule can be evaluated precisely and quantitatively by measurements of linewidth (or lifetime), saturation intensity, and rate of emission at saturation. These measurements are much more difficult and less precise at room temperature because of the limited stability of molecules in these conditions. 2. because of spectral selectivity at low temperature, a large number of molecules can be coupled to the same nanoantenna, allowing comparison of the antenna effect on molecules at different positions. This is impossible at room temperature because each antenna can interact with at most one molecule at a time. 3. photobleaching and photoblinking are much reduced or suppressed at low temperature, which allows very precise determination of the optical properties. At room temperature, molecule fluctuate in position and orientation and eventually bleach. In the frame of the two-year project, the fellow has built up a new setup for cryogenic single-molecule microscopy. He had identified a promising host-guest system (dibenzoterrylene in anthracene or in para-dichlorobenzene) and a promising nano-antenna (a gold nanorod with dimensions 40 nm width and 84 nm length) to try the experiment. He has performed the preliminary spectroscopic experiments on this host-guest system to prepare the experiment. Unfortunately, his stay has not been long enough to write the publication of the latter part, nor to try the actual experiment. This will be attempted in the coming months by a PhD student succeeding the fellow.
Data: CORDIS, © European Union
Project objective
Our project is to combine single-molecule spectroscopy with plasmonic nanomaterials. We will use the fluorescence excitation lines of single molecules in a cryogenic experiment to probe the local field enhancement of single plasmonic antennas, as well as of periodic array of antennas. At low tem-peratures, spectral selection will enable us to address a large number of molecules (typically 100,000) independently in each focal spot, by tuning the excitation laser. Thereby, we will determine the position of the excited molecule by superresolution techniques and correlate it with its emission properties. The linewidth and saturation fluorescence intensity of each molecule will be used to determine the local field enhancement. By selecting many individual molecules, we will map the local field and the associated enhancement of the molecular emission. Compared to previous experiments, this method is non-invasive, non-destructive, and still provides high spatial resolution. The local-field map will be used for further optimization of the nanoantennas in collaboration with a group in charge of the nanofabrication. The optimized antennas will allow us to enhance light-matter interaction and eventually, to manipulate single photons with single molecules.
Original text from CORDIS.
Participants
- UNIVERSITEIT LEIDEN · LeidenCoordinatorNetherlands
Links
Data: CORDIS, © European Union