CoLiME

The objective of this project is first to study the multiexcitonic radiative emission for individual colloidal nanocrystals (quantum dot) or nanoplatelets (quantum well) of II/VI semiconductors, then the coupling of this emission to surface plasmons. The aim of this project is to demonstrate, at room temperature , a strong coupling between the emission in the multiexcitonic regime and surface plasmons when the nanocrystals are placed in plasmonic antennas of very small volume. This project is divided into six parts, three for nanoplatelets, and three for nanocrystals , each of them includes optical experiments, chemical synthesis and modeling. It associates 3 teams, two experimental in optics and chemistry and one in theory. It has been shown that at room temperature, for CdSe /CdS quantum dots deposited at the individual scale on a glass slide and subjected to increasing excitation intensities in a continuous regime, their emission spectrum broadens, their emission intensity increases more than a simple two-level system would and this in a non-linear manner. Preliminary studies show an important contribution of radiative multiexcitons in this process. The modeling of these observations, in progress, is based on a statistical description of the emission from a quasi-equilibrium of the excitonic populations. We propose to study experimentally and theoretically this multiexcitonic emission in pulsed and continuous regime for nanocrystals such as quantum boxes and colloidal nanoplatelets. In a second step, we will study how in multiexcitonic emission regime, the emission from an individual nanocrystal or nanoplatelets couples to a surface plasmon. Finally, we will place the nanoemitter in a very small volume plasmonic cavity in order to demonstrate the strong coupling between the emission of the individual nano-emitter and the plasmonic mode of the cavity.