Regensburg 2022 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 39: Quantum Dots and Wires 6: II-VI and related
HL 39.2: Talk
Friday, September 9, 2022, 09:45–10:00, H32
Collective Properties of CdSe-CdS giant-shell Quantum Dots — •Yannic Stächelin1, Artur Feld1, Agnes Weimer1, Michael Deffner2,3, Sonja Krohn4, Jan Steffen Niehaus4, and Holger Lange1,3 — 1Institut für Physikalische Chemie, Universität Hamburg, Hamburg, Germany — 2Institut für Anorganische und Angewandte Chemie, Universität Hamburg, Hamburg, Germany — 3The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — 4Fraunhofer IAP-CAN, Hamburg, Germany
CdSe-CdS core-giant-shell QDs are nowadays available with near-unity quantum yields, which makes them interesting candidates for lasing or display applications. Bright, high-PLQY QDs might also contribute to photonic quantum technologies as building blocks. QDs can realize deterministic photon-emitters and enable key quantum photonic resources and functionalities. Interaction of densely packed QDs can lead to collective phenomena like excitonic and photonic coupling, superfluorescence and enhanced quantum coherence. Incoherent dephasing processes may deteriorate the inherent quantum properties of QDs. We investigate dependencies of exciton formation in CdSe-CdS giant-shell QDs and interaction in dense ensembles of QDs via ultrafast THz and transient absorption spectroscopy. Polymer-micelles are used to produce dense ensembles containing a variable amount of QDs. In dense ensembles, we observe the onset of a collective dynamic depending on the excitation conditions, which are thus a means of controlling the dynamics.