2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Förster transfer in coupled colloidal type-II and type-I quantum dots

L.G. Mourokh, I.L. Kuskovsky, A.Yu. Smirnov, H. Matsui
Queens College (CUNY), US

type-II colloidal core-shell quantum dots, time-resolved photoluminescence, Förster transfer

We examine theoretically resonant non-radiative exciton (Förster) transfer in the system of colloidal core-shell quantum dots (QDs) of different types. In this, the type-II QDs with electrons and holes separated in the real space have much longer recombination time than the type-I QDs with both electrons and holes confined in the core region. We show that when the type-I QD (acceptor) is coupled with the type-II QD (donor), the electron-hole pair optically excited in the type-II QD can be transferred to the type-I QD non-radiatively, if the recombination time of the former is larger than the time of the exciton transfer. Correspondingly, the time-resolved photoluminescence signal from the type-I QDs would be modified both quantitatively and qualitatively. We also discuss the feasibility to use this effect in a pathogen detection platform aimed at a single molecule level. With the QDs functionalized with antibodies to target pathogens, their presence will manifest itself by allowing or disallowing the Förster transfer by either bringing QDs closer to each other or changing electrostatic environmental properties, respectively. This “On-or-Off” scheme can work in both liquids and gases.

Nanotech 2008 Conference Program Abstract