Controlled influence of a Plasmonic nano-antenna on a single molecule Instersystem Crossing Rate – PlamonISC
The PlasmonISC project has two objectives :
1/ the development of a new method for the functionalization of a scanning probe with a single nanoparticle
2/ measure the influence of a nanoparticle on the intersystem crossing (ISC) rate of a single molecule
The reproducible fabrication of scanning probes having a nanoparticle with specific optical properties firmly attached to its apex is of great interest for the nanophotonic community. Such probes can be used to perform subwavelength optical characterization, tip-enhanced Raman spectroscopy, analysis of evanescent fields, or to measure single molecule orientations to name a few. However such tips are difficult to produce in a reliable way.
In the PlasmonISC project, we propose to use optical tweezers in a microfluidic chamber. The idea is to optically trap a gold nanoparticle, check its spectral properties in-situ, and put it in contact with the apex of a pulled optical fiber. Thanks to the controlled liquid environement provided by the microfluidic chamber, we will be able to use different wet chemistry solutions to strongly bond the nanoparticle to the glass tip.
If successfull this new method will provide robust functionalized glass tip with a single nanoparticle with known spectral properties at tis apex.
Using these functionnalized probes, we want to measure the changes induced by a nanoparticle on the ISC rate of a single molecule. To do this, we will use the terrylene/paraterphenyl system, well known in the litterature and by the coordinator. Terrylene molecules in a para-terphenyl matrix are bright single photon emitter that are very stable, even in a thin film. The sample will be placed on an inverted optical microscope with different collection paths: spectroscopy, camera or Handburry-Brown Twiss setup for anti-bunching measurements. The nanoparticle will be brought in close proximity using shear-force atomic force microscopy. This allows to measure the same molecule with and without the gold nanoparticle, and to correct for background emission. Such an experiment will give us quantitative information on the induced changes in all the rates involved in the molecule fluorescence, and in particular on changes in ISC rates.
To our knowledge this will be the first quantitative measurement of ISC rate changes induces by a nano-antenna on a single molecule.
We think that this controlled approach wil give us a better understanding of the physical processes at play, and our findings should provide guidelines for the designs of hybrid plasmonic OLED or nanolasers.
This project will enable the coordinator to develop his research themes through an experimental platform of high performance, in synergy with the members of his group. If successful, this project will also be a springboard for other sources of national and European funding.
Monsieur Simon VASSANT (Service de physique de l'état condensé)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
SPEC Service de physique de l'état condensé
Help of the ANR 307,789 euros
Beginning and duration of the scientific project: January 2020 - 48 Months