Method for controlling solubility of quantum dots

Functionalization of quantum dots (QD) surface by exchanging the native ligands with other ligands capable of adjusting the solubility of said nanoparticle, in particular in water and other polar solvents.

Title of the patent Method for controlling solubility of quantum dots
Thematic area Chemistry and biotechnology
Ownership Alma Mater Studiorum - Università di Bologna and Università di Basilea
Inventors Alberto Credi, Serena Silvi, Tommaso Avellini, Christophe Lincheneau
Protection International application
Licensing status Available for licensing agreement
Keywords Quantum dot, lipoic acid, resin, ligand
Filed on May 07, 2013

Quantum dots (QDs) are semiconductor nanocrystals endowed with unique optical and electronic properties, such that they are emerging as substitutes for molecular fluorophores in a variety of technological applications.

QDs of, e.g., CdSe exhibit a high light absorption and an intense luminescence in the UV-visible region, whose wavelength can in both cases be modulated by adjusting the diameter of the particle.

QDs are chemically and photochemically very stable, and are excellent two-photon absorbers. For these peculiar properties, QDs are employed in several applications related to the use of luminescence: (bio)chemical analysis, diagnostic imaging, medical therapy, photovoltaic solar cells, and LED devices for lighting and displays.

Method for the modification of the QD surface by exchanging the native ligands with other molecular ligands capable of binding to the nanoparticle in a stable manner.

The methodology enables to obtain nanocrystals with high purity and compatible with various polar organic solvents and/or water.

The QDs obtained maintain largely their optical properties and are stable in solution for a long time (at least 6 months).

The invention deals with the field of luminescent semiconductor nanocrystals soluble in water and in common organic solvents.

In comparison with existing ligand exchange methods, the developed procedure allows to:

  • shorten the reaction period by 5-6 times;
  • make the synthesis and purification operations substantially simpler;
  • perform the reaction at room temperature and in air.

The method is flexible and versatile: it can be adapted to different types of nanocrystals and of ligands, and can be therefore employed for the functionalization of QDs.