Highly luminescent nanostructures and methods of producing same
Highly luminescent nanostructures, particularly highly luminescent quantum dots, are provided. The nanostructures have high photoluminescence quantum yields and in certain embodiments emit light at particular wavelengths and have a narrow size distribution. The nanostructures can comprise ligands, including C5-C8 carboxylic acid ligands employed during shell formation and/or dicarboxylic or polycarboxylic acid ligands provided after synthesis. Processes for producing such highly luminescent nanostructures are also provided, including methods for enriching nanostructure cores with indium and techniques for shell synthesis.
1. A composition comprising: a nanostructure; and a C5-C8 carboxylic acid ligand bound to a surface of the nanostructure, wherein the nanostructure is an InP/ZnS x Se 1-x /ZnS core/shell quantum dot, where 0≦x≦1.
2. The composition of claim 1 , wherein 0.25≦x≦0.75.
3. The composition of claim 2 , wherein x is about 0.5.
4. The composition of claim 2 , wherein the ligand is hexanoic acid.
5. The composition of claim 4 , further comprising a dicarboxylic or polycarboxylic acid ligand bound to the surface of the nanostructure, wherein the dicarboxylic or polycarboxylic acid ligand is dodecenyl succinic acid.
6. The composition of claim 1 , wherein the nanostructure is embedded in a matrix.
7. A device comprising the composition of claim 1 .
8. The composition of claim 1 , wherein the ligand is an alkyl carboxylic acid.
9. The composition of claim 1 , wherein the ligand is an unbranched alkyl carboxylic acid.
10. The composition of claim 1 , wherein the ligand is hexanoic acid.
11. The composition of claim 1 , wherein the ligand is pentanoic acid.
12. The composition of claim 1 , wherein the ligand is an alkenyl carboxylic acid or an alkynyl carboxylic acid.
13. The composition of claim 1 , wherein the ligand is 4-pentanoic acid.
14. The composition of claim 1 , wherein the ligand is an unbranched monocarboxylic acid.
15. The composition of claim 1 , further comprising a dicarboxylic or polycarboxylic acid ligand bound to the surface of the nanostructure.
16. The composition of claim 15 , wherein the dicarboxylic or polycarboxylic acid ligand is dodecenyl succinic acid.
17. The composition of claim 1 , further comprising a long chain fatty acid ligand bound to the surface of the nanostructure, which long chain fatty acid comprises at least 12 carbon atoms.