Methods for coating semiconductor nanocrystals

Abstract

A coated quantum dot and methods of making coated quantum dots are provided. Products including quantum dots described herein are also disclosed.

1 - 36 . (canceled) 
     
     
         37 . A method of making quantum dots having a coating thereon comprising:
 providing a first reaction mixture comprising core quantum dots, a zinc carboxylate and a chalcogen source at a temperature of greater than 240° C. in the substantial absence of an amine species;   forming a first coating on the core quantum dots from the zinc carboxylate and chalcogen source to form first coated quantum dots;   providing a second reaction mixture comprising one or more metal carboxylates and one or more chalcogenide sources with the first coated quantum dots at a temperature of greater than 240° C. in the substantial absence of an amine species; and   forming a second coating on the first coated quantum dots from the one or metal carboxylates and the one or more chalcogenide sources.   
     
     
         38 . A method in accordance with  claim 37  wherein the temperature of the first reaction mixture is greater than 280° C. 
     
     
         39 . A method in accordance with  claim 37  wherein the temperature of the second reaction mixture is greater than 280° C. 
     
     
         40 . The method of  claim 37  wherein the core quantum dots comprise a Group II-VI semiconductor material. 
     
     
         41 . The method of  claim 37  wherein a first coating comprising one or more zinc chalcogenides is formed on the core quantum dots in the absence of amine species. 
     
     
         42 . The method of  claim 37  wherein the second coating comprises Cd X Zn 1-X S wherein 0<x<1. 
     
     
         43 . The method of  claim 37  wherein the core quantum dots comprise CdSe. 
     
     
         44 . Quantum dots comprising a quantum dot core with a first coating comprising zinc chalcogenide on an outer surface of the quantum dot core and an outermost coating comprising a semiconductor material, wherein the outermost coating is substantially free of amine species. 
     
     
         45 . The quantum dots of  claim 44  wherein the outermost coating comprises a semiconductor material comprising Cd X Zn 1-X S wherein 0<x<1. 
     
     
         46 - 49 . (canceled) 
     
     
         50 . A composition comprising a host material and quantum dots in accordance with  claim 44  wherein the host material has reduced discoloration upon exposure to light flux in excess of 1 W/cm 2  and/or a temperature >100° C. compared to a control composition comprising the host material and control quantum dots including an amine species associated with an outermost surface of the control quantum dots. 
     
     
         51 . The composition of  claim 50  wherein the host material comprises a polymer matrix. 
     
     
         52 . A quantum dot prepared by a method in accordance with  claim 37  wherein the quantum dot has a solid state EQE of at least 90%. 
     
     
         53 - 113 . (canceled) 
     
     
         114 . The method of  claim 37  wherein the chalcogen source comprises a sulfur source. 
     
     
         115 . The method of  claim 114  wherein the temperature of the first reaction mixture is at least about 270° C. 
     
     
         116 . The method of  claim 114  wherein the temperature of the first reaction mixture is at least about 300° C., 
     
     
         117 . The method of  claim 114  wherein the temperature of the first reaction mixture is greater than 310° C. 
     
     
         118 . The method of  claim 37  wherein the chalcogen source comprises a selenium source. 
     
     
         119 . The method of  claim 118  wherein the temperature of the first reaction mixture is at least about 300° C. 
     
     
         120 . The method of  claim 118  wherein the temperature of the first reaction mixture is greater than 310° C. 
     
     
         121 . Quantum dots in accordance with  claim 44  wherein the quantum dot core comprises cadmium and selenium and the outermost coating comprises a semiconductor material comprising Cd X Zn 1-X S wherein 0<x<1.