Unlike many organic chromofores, semiconductor quantum dots can accomodate multiple excitations. Multiple excitation leads, however, to the opening of new and rapid non-radiative relaxation routes via an Auger mechanism, where an exciton recombines and transfers the energy to a spectator charge. By controlling the composition in a multicomponent ("onion") quantum dot, it is possible to control and utilize this relaxation mechanism.
We have been using a combination of ensemble and single-particle spectroscopy to investigate many unique pohenomena in these particles which exploit enahnced exciton-exciton interactions. These include the first observation of carrier multiplication process in type-II core/shell quantum dot heterostructures and studies elucidating the origin of luminescence interittency in quantum dots..
We have, more recently, been developing colloidal double quantum dots - two coupled quantum dots packaged into a single nanocrystal, and exhibiting unique properties from two-color antibunching, through controlled blinking to photoluminescence upconversion. See our recent review on the topic "Colloidal double quantum dots" in Accounts of Chemical Research.
- A. Teitelboim, D. Oron, “Broadband near-infrared to visible upconversion in quantum dot-quantum well heterostructures”, ACS Nano 10, 446 (2016).
- R. Tenne, S. Pedetti, M. Kazes, S. Ithurria, L. Houben, B. Nadal, D. Oron, B. Dubertret, "From dilute isovalent substitution to alloying in CdSeTe nanoplates", Phys. Chem. Chem. Phys. 18, 15292 (2016).
- N. Meir, B. Martín-García, I. Moreels, D. Oron, “Revisiting the anion framework conservation in cation exchange processes”, Chem. Mat. 28, 7872 (2016).
- A. Ben Moshe, A. Teitelboim, D. Oron, G. Markovich, “Probing the Interaction of Quantum Dots with Chiral Capping Molecules using Circular Dichroism Spectroscopy”, Nano Lett. 16, 7467 (2016).
- S. Luo, M. Kazes, H. Lin, D. Oron, “Strain induced Type-II band alignment control in CdSe nanoplatelets / ZnS sensitized solar cells”, J. Phys. Chem. C 121, 11136 (2017).
- G. Yang, M. Kazes, D. Oron, “Chiral 2D Colloidal Semiconductor Quantum Wells”, Adv. Funct. Mat. 1802012 (2018).