Expérimental et théorique
CdSe/CdS core/shell nanocrystal are excellent bright nano-emitters, awarded by the Nobel Price 2023. At room temperature, they behave as high quantum efficiency single photon source thanks to the electronic confinement and efficient Auger processes. Single photon emission can be described by the recombination of a single exciton within a simple two-level system. Under low excitation power at room temperature, the emission linewidth is approximately Δ𝜆 ≈ 20 nm. However, by increasing the excitation power, emission spectrum broadens dramatically up to Δ𝜆 ≈ 150 nm. Moreover, the emission intensity grows non-linearly with increasing excitation power. The two- levels system paradigm fails for interpreting those features. We have recently developed a model based on the radiative recombination of multiple excitonic levels within a single nanocrystal , relying on statistical description of electron and hole populations in a quasi-equilibrium and on their recombination. During the internship the student will consider different types of nano-emitter, quantum dots or quantum wells, and will study their emission under high excitation. He/She will then analyse the experimental datas using among others Bayesian methods, and extent our theoretical model. During the PhD, in the framework of the ANR CoLIMe, starting in 2024, and in continuity of the internship, we will study strong coupling between multiexcitonic emission of those nanoemitters and plasmonic antennas.