Licensable Technologies : Materials : Composites

Quantum Dots Incorporated into Thin Films

Abstract
LANL scientists have developed three new sol-gel methods for preparing solid composites that incorporate colloidal semiconductor nanocrystals (quantum dots) or colloidal metal nanocrystals. These novel processes enable production of transparent, solid matrix materials and coatings with beneficial properties that depend on the identity of the encapsulated nanocrystals. The first process involves forming an admixture of colloidal nanocrystals, a lower alcohol, a non-polar co-solvent, and a sol-gel precursor material and preparing the solid composite from the admixture. In a second approach, the colloidal nanocrystals become intimately connected to the sol-gel matrix. The admixture is formed by first combining, in a solvent, multi-functional molecules and colloidal nanocrystals passivated with hydrophobic ligands. One portion of the multifunctional ligand binds to the nanocrystal while the other is left on the periphery where it co-condenses with the added sol-gel precursor. The product is a robust material that can be densely populated with nanocrystals. A third method entails admixing colloidal nanocrystals with an amphiphilic polymer in a solvent to form an alcohol-soluble, colloidal nanocrystal-polymer complex that may be further admixed with a sol-gel precursor. This process is applicable to a wide variety of nanocrystals capped with hydrophobic groups. In many cases, the nanocrystals are incorporated into the sol-gel matrix without a large decrease in quantum yield (for, e.g., quantum dots). In all cases the sol-gel-based solutions are highly processable and can be used to form solid composites in the shape of planar films or can be used to mold solid composites of various other shapes and configurations. All three methods have been refined and can be commercialized immediately.

Application(s)

• Nanocrystal films
• Optical devices (e.g., optical switches, optical amplifiers, dynamic holography materials, lasers)
• Light-emitting diodes and solid-state lighting (as tunable emitters)
• Coatings
• UV filters

Advantages

• Large, tunable volume loadings of nanocrystals
• Large, tunable refractive indices
• Tunable absorption and emission spectra
• High quantum yields (quantum dots)
• Low cost fabrication

IP Status: Contact Licensing Executive for Details

Reference Number: 287

S Number: DOE reference no.(s): 100,641; 102,311; 112,817

Patents & Applications:
United States National Patent Number 7226953 Issued on 06/05/2007

Posted: 02-18-2005

Contact
Laura Barber
Technology Transfer Division
Los Alamos National Laboratory
P.O. Box 1663, MailStop C334
(505) 667-9266
ljbb@lanl.gov