Methods for forming nanocrystals with position-controlled dopants

Abstract

A doping method using a three-step synthesis to make high-quality doped nanocrystals is provided. The first step includes synthesizing starting host particles. The second step includes dopant growth on the starting host particles. The third step includes final shell growth. In one embodiment, this method can be used to form Mn-doped CdS/ZnS core/shell nanocrystals. The Mn dopant can be formed inside the CdS core, at the core/shell interface, and/or in the ZnS shell. The subject method allows precisely controlling the impurity radial position and doping level in the nanocrystals.

What is claimed is: 
     
         1 . A doped nanocrystal, comprising:
 a base material;   a plurality of dopant atoms radially positioned about the base material; and   a host shell surrounding the base material and the plurality of dopant atoms.   
     
     
         2 . The doped nanocrystal according to  claim 1 , wherein the base material and the host shell provide a spherical homogeneous structure. 
     
     
         3 . The doped nanocrystal according to  claim 2 , wherein the spherical homogeneous structure comprises CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, PbS, PbSe, PbTe, InP, InAs, GaP, GaAs, ZnO, SiO 2 , TiO 2 , ZrO 2 , Fe 2 O 3 , Fe 3 O 4 , SnO 2 , In 2 O 3 , Gd 2 O 3 , Ce 2 O 3 , Tb 2 O 3 ), Au, Ag, Cu, Pt, Fe, or Pt x Fe y . 
     
     
         4 . The doped nanocrystal according to  claim 1 , wherein the base material and the host shell provide a core/shell structure. 
     
     
         5 . The doped nanocrystal according to  claim 4 , wherein the base material is a core comprising CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, PbS, Pb Se, PbTe, InP, InAs, GaP, GaAs, ZnO, SiO 2 , TiO 2 , ZrO 2 , Fe 2 O 3 , Fe 3 O 4 , SnO 2 , In 2 O 3 , Gd 2 O 3 , Ce 2 O 3 , Tb 2 O 3 ), Au, Ag, Cu, Pt, Fe, or Pt x Fe y . 
     
     
         6 . The doped nanocrystal according to  claim 4 , wherein the host shell comprises CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, PbS, PbSe, PbTe, InP, InAs, GaP, GaAs, ZnO, SiO 2 , TiO 2 , ZrO 2 , Fe 2 O 3 , Fe 3 O 4 , SnO 2 , In 2 O 3 , Gd 2 O 3 , Ce 2 O 3 , Tb 2 O 3 ), Au, Ag, Cu, Pt, Fe, or Pt x Fe y . 
     
     
         7 . The doped nanocrystal according to  claim 1 , wherein the plurality of dopant atoms includes dopant atoms selected from the group consisting of In, P, Cd, Mn, Zn, S, Se, Br, Li, Sn, Te, Ag, Au, Cu, Cr, Co, Fe, Ni, Cl, Tb, Gd, Er, Ce, Nd, Dy, Pm, and Eu. 
     
     
         8 . The doped nanocrystal according to  claim 1 , wherein the plurality of dopant atoms comprises dopant atoms that are magnetic impurities, conventional impurities, or a combination of magnetic and conventional impurities. 
     
     
         9 . The doped nanocrystal according to  claim 1 , wherein the plurality of dopant atoms are radially positioned within the base material, at the surface of the base material, and/or at a distance from the surface of the base material.