SYNTHESIS OF Pb ALLOY AND CORE/SHELL NANOWIRES

Abstract

Embodiments of the present invention are directed to methods of producing nanowires comprising a PbSe core and a PbS shell, and methods of producing nanowires comprising a PbSe core and a PbTe shell. The method for producing the PbSe core/PbS shell nanowires comprise the steps of providing a core/shell growth solution comprising PbSe nanowires, heating the core/shell growth solution to a temperature sufficient to produce a PbS shell over the PbSe nanowires, adding a Pb precursor solution to the core/shell growth solution, and adding an S precursor solution to the core/shell growth solution after the addition of the Pb precursor to produce nanowires comprising a PbSe core and a PbS shell.

1 . A method for producing nanowires comprising a PbSe core and a PbS shell comprising the steps of:
 providing a core/shell growth solution comprising PbSe nanowires;   heating the core/shell growth solution to a temperature sufficient to produce a PbS shell over the PbSe nanowires;   adding a Pb precursor solution to the core/shell growth solution; and   adding an S precursor solution to the core/shell growth solution after the addition of the Pb precursor to produce nanowires comprising a PbSe core and a PbS shell.   
     
     
         2 . The method of  claim 1  wherein the core/shell growth solution comprises tri-octyl phosphine (TOP) and diphenyl ether (DPE). 
     
     
         3 . The method of  claim 1  wherein the S precursor solution comprises S and TOP. 
     
     
         4 . The method of  claim 1  wherein the core/shell growth solution was heated to a temperature of about 130° C. 
     
     
         5 . The method of  claim 1  further comprising heating the core/shell growth solution after the addition of the PbSe nanowires to a temperature of about 130° C. 
     
     
         6 . The method of  claim 1  wherein the nanowire comprising a PbSe core and a PbS shell comprise a thickness of about 11 nm. 
     
     
         7 . A PbSe core/PbS shell nanowire produced by the method of  claim 1 . 
     
     
         8 . A method for producing nanowires comprising a PbSe core and a PbTe shell comprising the steps of:
 providing a Pb precursor solution;   adding a Te precursor solution to the Pb precursor solution to produce a PbTe solution;   providing a core/shell growth solution heated to a temperature of about 150° C., wherein the core/shell growth solution comprises PbSe nanowires; and   adding the PbTe solution to the core/shell growth solution to form nanowires comprising a PbSe core and a PbTe shell.   
     
     
         9 . The method of  claim 8  further comprising the step of reheating the core/shell growth solution after the addition of the PbTe solution to a temperature of about 130° C. 
     
     
         10 . The method of  claim 8  further comprising isolating the PbSe/PbTe core/shell nanowires from the core/shell growth solution by centrifugation in the presence of toluene or ethanol. 
     
     
         11 . The method of  claim 8  wherein the core/shell growth solution is heated to a temperature of about 190° C. prior to the addition of the PbTe solution. 
     
     
         12 . The method of  claim 8  wherein the Te precursor comprises Te and TOP. 
     
     
         13 . The method of  claim 8  wherein the Te precursor is added dropwise to the Pb precursor solution. 
     
     
         14 . The method of  claim 8  wherein the core/shell growth solution comprises TOP and DPE. 
     
     
         15 . The method of  claim 8  wherein the PbTe shell comprises a thickness of about 5 to about 30 nm. 
     
     
         16 . The method of  claim 8  wherein the nanowire comprising the PbSe core and PbTe shell comprises a thickness of about 10 to about 45 nm. 
     
     
         17 . A PbSe core/PbTe shell nanowire produced by the method of  claim 1