Semiconductor nanocrystals and compositions and devices including same

Abstract

A semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light with an improved photoluminescence quantum efficiency. Also disclosed are populations of semiconductor nanocrystals, compositions and devices including a semiconductor nanocrystal capable of emitting light with an improved photoluminescence quantum efficiency. In one embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%. In another embodiment, a semiconductor nanocrystal includes a core comprising a first semiconductor material comprising zinc, cadmium, and sulfur and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material. In a further embodiment, a semiconductor nanocrystal includes a core comprises a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material comprising at least three chemical elements, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation. In a further embodiment, a semiconductor nanocrystal including a core comprises a first semiconductor material comprising zinc, cadmium, and selenium and a shell disposed over at least a portion of the core, the shell comprising a second semiconductor material, wherein the semiconductor nanocrystal is capable of emitting light with a photoluminescence quantum efficiency greater than about 60% upon excitation.

1 - 43 . (canceled) 
     
     
         44 . A population of semiconductor nanocrystals, each semiconductor nanocrystal including a core comprising a first semiconductor material comprising at least three chemical elements and a shell disposed over at least a portion of a surface of the core, the shell comprising a second semiconductor material, wherein the population is capable of emitting light upon excitation with a photoluminescence quantum efficiency greater than about 65%. 
     
     
         45 - 47 . (canceled) 
     
     
         48 . A population in accordance with  claim 44  wherein the population is capable of emitting light with a photoluminescence quantum efficiency greater than about 70% upon excitation. 
     
     
         49 . A population in accordance with  claim 44  wherein the population is capable of emitting light with a photoluminescence quantum efficiency greater than about 80% upon excitation. 
     
     
         50 . A population in accordance with  claim 44  wherein the population is capable of emitting light with a photoluminescence quantum efficiency greater than about 90% upon excitation. 
     
     
         51 . A population in accordance with  claim 44  wherein the semiconductor nanocrystals are capable of emitting light with a photoluminescence quantum efficiency greater than about 95% upon excitation. 
     
     
         52 . A population in accordance with  claim 44  wherein the population is capable of emitting light with a photoluminescence quantum efficiency of about 100% upon excitation. 
     
     
         53 . A population in accordance with  claim 44  wherein the first semiconductor material comprises an alloy. 
     
     
         54 . A population in accordance with  claim 44  wherein the first semiconductor material comprises a homogeneous alloy. 
     
     
         55 . A population in accordance with  claim 44  wherein the second semiconductor material comprises two or more chemical elements. 
     
     
         56 . A population in accordance with  claim 44  wherein the first semiconductor material comprises zinc, cadmium, and sulfur. 
     
     
         57 . A population in accordance with  claim 44  wherein the second semiconductor material comprises zinc and sulfur. 
     
     
         58 . A population in accordance with  claim 44  wherein the light includes a maximum peak emission with a full width at half maximum of not more than 40 nm. 
     
     
         59 . A population in accordance with  claim 44  wherein the light includes a maximum peak emission with a full width at half maximum of not more than 30 nm. 
     
     
         60 . A population in accordance with  claim 44  wherein the light includes a maximum peak emission with a full width at half maximum of not more than 20 nm. 
     
     
         61 . (canceled) 
     
     
         62 . (canceled) 
     
     
         63 . A population in accordance with  claim 44  wherein the shell has a thickness ranging up to about 20 monolayers. 
     
     
         64 . A population in accordance with  claim 44  wherein, the first semiconductor material comprises Zn x Cd 1-x S, wherein 0<x<1. 
     
     
         65 . A population in accordance with  claim 44  wherein the second semiconductor material comprises ZnS. 
     
     
         66 . A population in accordance with  claim 44  wherein the color of the light emitted by the semiconductor nanocrystal is longer than the color of the light emitted by the core without the shell. 
     
     
         67 - 129 . (canceled)