Journal of Nanomedicine & Nanotechnology

New-PEGylated PbS quantum dots for water-based applications

9^th Nano Congress for Next Generation

August 01-02, 2016 Manchester, UK

Francesca S Freyria, Jose Cordero, Justin Caram and Moungi Bawendi

Massachusetts Institute of Technology, USA

Posters & Accepted Abstracts: J Nanomed Nanotechnol

Abstract:

Colloidal nanochemistry has received tremendous interest over the past decade, especially the synthesis of nanoscale semiconductor crystals capped with surfactant molecules and dispersed in solution (quantum dots (QDs)). Among them, near-infrared emitting lead-based QDs have gained considerable attention since they exhibit attractive properties for the development of various emerging applications, from optoelectronic-devices to photovoltaic cells and to fluorescence-based optical imaging. Most of these applications require water as dispersion medium, whereas QDs synthesis is normally carried out in organic solvents, thus giving quantum dots soluble in organic phases but insoluble in polar solvents. A ligand exchange process after the synthesis is the common route to obtain water-soluble quantum dots. This two-steps method brings usually a decrease of the quantum yield, a possible emission shift and an inhomogeneity in the particle size distribution, with many drawbacks for the final applications. This is more evident for the near infrared and infrared emitting nanocrystals, whose optical quality even in organic phases is still not as high as for the visible emitting QDs. We have developed a new kind of synthesis for water soluble PbS QDs, based on norbornene click-chemistry. This new synthesis method eliminates the need of ligand exchange and confers a very high quantum yield and a high optical stability over months in water. Finally, a hybrid system as model for solar energy devices has been physico-chemically and optically studied, by coupling a supramolecular self-organization system with aqueous dispersions of PbS QDs.

Biography :

Email: freyria@mit.edu