Tellurium-containing nanocrystalline materials

Abstract

Tellurium-containing nanocrystallites are produced by injection of a precursor into a hot coordinating solvent, followed by controlled growth and annealing. Nanocrystallites may include CdTe, ZnTe, MgTe, HgTe, or alloys thereof. The nanocrystallites can photoluminesce with quantum efficiencies as high as 70%.

1 . A method of producing a population of cadmium chalcogenide nanocrystals comprising:
 preparing a mixture of a cadmium-containing compound and a chalcogenide-containing compound in a mole ratio that is rich in cadmium; and   growing cadmium chalcogenide nanocrystals from the mixture.   
     
     
         2 . The method of  claim 1 , wherein the mole ratio of cadmium-containing compound to chalcogenide-containing compound is greater than 1:1. 
     
     
         3 . The method of  claim 1 , wherein the mole ratio of cadmium-containing compound to chalcogenide-containing compound is about 2:1. 
     
     
         4 . The method of  claim 1 , wherein the cadmium chalcogenide is selected from the group consisting of CdS, CdSe, CdTe, and mixtures thereof. 
     
     
         5 . The method of  claim 1 , wherein the cadmium chalcogenide is CdTe. 
     
     
         6 . The method of  claim 1 , wherein the cadmium chalcogenide is CdSe. 
     
     
         7 . The method of  claim 1 , further comprising depositing an overcoating of a semiconductor material on a surface of the cadmium chalcogenide nanocrystals. 
     
     
         8 . The method of  claim 7 , wherein the semiconductor material in the overcoating comprises ZnS, ZnSe, and mixtures thereof. 
     
     
         9 . The method of  claim 7 , wherein the cadmium chalcogenide is CdSe and the semiconductor material in the overcoating is ZnS. 
     
     
         10 . The method of  claim 7 , further comprising depositing an organic layer on the outer surface of the coated cadmium chalcogenide nanocrystals. 
     
     
         11 . The method of  claim 1 , wherein the population of cadmium chalcogenide nanocrystals exhibits photoluminescence having a quantum yield of 30% or greater. 
     
     
         12 . The method of  claim 6 , wherein the population of coated cadmium chalcogenide nanocrystals exhibits photoluminescence having a quantum yield of 30% or greater. 
     
     
         13 . The method of  claim 1 , wherein the population of cadmium chalcogenide nanocrystals is substantially monodisperse. 
     
     
         14 . The method of  claim 1 , wherein the population of cadmium chalcogenide nanocrystals has an rms deviation in diameter of no more than 10%. 
     
     
         15 . The method of  claim 1 , wherein the population of cadmium chalcogenide nanocrystals has an rms deviation in diameter of no more than 5%. 
     
     
         16 . The method of  claim 13 , wherein the population of cadmium chalcogenide nanocrystals has a mean diameter in the range of about 20 Å to about 125 Å. 
     
     
         17 . The method of  claim 1 , wherein the population of cadmium chalcogenide nanocrystals emits light in a spectral range of no more than 40 nm full width at half max (FWHM) when irradiated. 
     
     
         18 . The method of  claim 7 , wherein the population of coated cadmium chalcogenide nanocrystals emits light in a spectral range of no more than 40 nm full width at half max (FWHM) when irradiated. 
     
     
         19 . A population of cadmium chalcogenide nanocrystals, each nanocrystal comprising a core including cadmium and a chalcogenide in a mole ratio that is rich in cadmium. 
     
     
         20 . The population of  claim 19 , further comprising an overcoating of a semiconductor material on a surface of the core. 
     
     
         21 . The population of  claim 19 , wherein the core is an alloy.