Method of semiconductor nanocrystal synthesis

Abstract

A method is described for the manufacture of semiconductor nanoparticles. Improved yields are obtained by use of a reducing agent or oxygen reaction promoter.

1 - 27 . (canceled)  
     
     
         28 . A method of producing nanoparticle shells comprising: (a) mixing nanoparticles with at least one coordinating solvent to form a first mixture; (b) heating the first mixture to a temperature that is sufficiently high to form a shell on the nanoparticles when first and second precursors are added; (c) introducing first and second precursors into the first mixture to form a second mixture thereby resulting in the formation of shells on a plurality of nanoparticles; and (d) cooling the second mixture to stop further growth of the shell; wherein the method further comprises exposing the first or second mixture to a reaction promoter selected from the group consisting of oxygen and a reducing agent.  
     
     
         29 . The method of  claim 28  wherein the reaction promoter is a reducing agent.  
     
     
         30 . The method of  claim 29  wherein the exposing step comprises adding the reducing agent to the mixture.  
     
     
         31 . The method of  claim 29  wherein the reducing agent is a chemical reducing agent selected from the group consisting of tertiary, secondary, and primary phosphines; amines; hydrazines; hydroxyphenyl compounds; hydrogen; hydrides; metals; boranes; aldehydes; alcohols; thiols; reducing halides; and polyfunctional reductants.  
     
     
         32 . The method of  claim 29  wherein the reducing agent is a cathode.  
     
     
         33 . The method of  claim 32  wherein the cathode is made of a material selected from the group consisting of platinum, silver and carbon.  
     
     
         34 . The method of  claim 28  wherein the reaction promoter is oxygen.  
     
     
         35 . The method of  claim 34  wherein the exposing step comprises directly exposing the mixture to a source of oxygen.  
     
     
         36 . The method of  claim 34  wherein the oxygen is formed in situ.  
     
     
         37 . The method of  claim 36  wherein the oxygen is formed by a redox reaction.  
     
     
         38 . The method of  claim 37  wherein the exposing step comprises adding a reducing agent selected from the group consisting of tertiary, secondary, and primary phosphines; amines; hydrazines; hydroxyphenyl compounds; hydrogen; hydrides; metals; boranes; aldehydes; alcohols; thiols; reducing halides; and polyfunctional reductants.  
     
     
         39 . The method of  claim 34  wherein the exposing step comprises exposing a coordinating solvent to a source of oxygen and adding the exposed coordinating solvent to the mixture.  
     
     
         40 . The method of  claim 28  wherein the nanoparticles are semiconductive.  
     
     
         41 . The method of  claim 28  wherein an additive or additive precursor is included in step (a).  
     
     
         42 - 54 . (canceled)