Nanoparticles

Abstract

Method for producing a nanoparticle comprised of core, first shell and second shell semiconductor materials. Effecting conversion of a core precursor composition comprising separate first and second precursor species to the core material and then depositing said first and second shells. The conversion is effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticle core. Core/multishell nanoparticles in which at least two of the core, first shell and second shell materials incorporate ions from groups 12 and 15, 14 and 16, or 11, 13 and 16 of the periodic table. Core/multishell nanoparticles in which the second shell material incorporates at least two different group 12 ions and group 16 ions. Core/multishell nanoparticles in which at least one of the core, first and second semiconductor materials incorporates group 11, 13 and 16 ions and the other semiconductor material does not incorporate group 11, 13 and 16 ions.

1 . A nanoparticle comprising a core comprising a core semiconductor material, a first layer comprising a first semiconductor material provided on said core and a second layer comprising a second semiconductor material provided on said first layer, said core semiconductor material being different to said first semiconductor material and said first semiconductor material being different to said second semiconductor material, wherein:
 a) at least two of the core, first shell and second shell materials incorporate ions from groups 12 and 15 of the periodic table, groups 14 and 16 of the periodic table, or groups 11, 13 and 16 of the periodic table; or   b) the second shell material incorporates ions of at least two different elements from group 12 of the periodic table and ions from group 16 of the periodic table; or   c) at least one of the core, first and second semiconductor materials incorporates ions from groups 11, 13 and 16 of the periodic table and at least one other of the core, first and second semiconductor materials is a semiconductor material not incorporating ions from groups 11, 13 and 16 of the periodic table.   
     
     
         2 . A nanoparticle according to  claim 1 , wherein:
 at least two of the core, first shell and second shell materials incorporate ions from groups 12 and 15 of the periodic table, groups 14 and 16 of the periodic table, or groups 11, 13 and 16 of the periodic table; and   the other of the core, first and second semiconductor materials incorporates ions from the group consisting of: groups 12 and 15 of the periodic table, groups 13 and 15 of the periodic table, groups 12 and 16 of the periodic table, groups 14 and 16 of the periodic table, and groups 11, 13 and 16 of the periodic table.   
     
     
         3 . A nanoparticle according to  claim 1 , wherein:
 the second shell material incorporates ions of at least two different elements from group 12 of the periodic table and ions from group 16 of the periodic table; and   said second semiconductor material has the formula M x N 1-x E, where M and N are the group 12 ions, E is the group 16 ion, and 0<x<1.   
     
     
         4 . A nanoparticle according to  claim 3 , wherein 0.1<x<0.9. 
     
     
         5 . A nanoparticle according to  claim 1 , wherein:
 at least one of the core, first and second semiconductor materials incorporates ions from groups 11, 13 and 16 of the periodic table and at least one other of the core, first and second semiconductor materials is a semiconductor material not incorporating ions from groups 11, 13 and 16 of the periodic table; and   said at least one other of the core, first and second semiconductor materials not incorporating ions from groups 11, 13 and 16 of the periodic table incorporates ions from the group consisting of: groups 12 and 15 of the periodic table, groups 13 and 15 of the periodic table, groups 12 and 16 of the periodic table, and groups 14 and 16 of the periodic table.   
     
     
         6 . A nanoparticle according to  claim 1 , wherein the nanoparticle further comprises a third layer of a third semiconductor material provided on said second layer. 
     
     
         7 . A nanoparticle according to  claim 6 , wherein said third semiconductor material is selected from the group consisting of: a semiconductor material incorporating ions from groups 12 and 15 of the periodic table, a semiconductor material incorporating ions from groups 13 and 15 of the periodic table, a semiconductor material incorporating ions from groups 12 and 16 of the periodic table, a semiconductor material incorporating ions from groups 14 and 16 of the periodic table and a semiconductor material incorporating ions from groups 11, 13 and 16 of the periodic table. 
     
     
         8 . A nanoparticle according to  claim 1 , wherein the group 12 ions are selected from the group consisting of: zinc ions, cadmium ions, and mercury ions. 
     
     
         9 . A nanoparticle according to  claim 1 , wherein the group 15 ions are selected from the group consisting of: nitride ions, phosphide ions, arsenide ions, and antimonide ions. 
     
     
         10 . A nanoparticle according to  claim 1 , wherein the group 14 ions are selected from the group consisting of: lead ions, tin ions, and germanium ions. 
     
     
         11 . A nanoparticle according to  claim 1 , wherein the group 16 ions are selected from the group consisting of: sulfide ions, selenide ions, and telluride ions. 
     
     
         12 . A nanoparticle according to  claim 1 , wherein the group 11 ions are selected from the group consisting of: copper ions, silver ions, and gold ions. 
     
     
         13 . A nanoparticle according to  claim 1 , wherein the group 13 ions are selected from the group consisting of: aluminium ions, indium ions, and gallium ions. 
     
     
         14 . A method for producing a nanoparticle comprising a core comprising a core semiconductor material, a first layer comprising a first semiconductor material provided on said core and a second layer comprising a second semiconductor material provided on said first layer, said core semiconductor material being different to said first semiconductor material and said first semiconductor material being different to said second semiconductor material, wherein:
 a) at least two of the core, first shell and second shell materials incorporate ions from groups 12 and 15 of the periodic table, groups 14 and 16 of the periodic table, or groups 11, 13 and 16 of the periodic table; or   b) the second shell material incorporates ions of at least two different elements from group 12 of the periodic table and ions from group 16 of the periodic table; or   c) at least one of the core, first and second semiconductor materials incorporates ions from groups 11, 13 and 16 of the periodic table and at least one other of the core, first and second semiconductor materials is a semiconductor material not incorporating ions from groups 11, 13 and 16 of the periodic table,   the method comprising effecting conversion of a nanoparticle core precursor composition to the material of the nanoparticle core, depositing said first layer on said core and depositing said second layer on said first layer.   
     
     
         15 . A method according to  claim 14 , wherein said nanoparticle core precursor composition comprises first and second core precursor species containing the ions to be incorporated into the growing nanoparticle core. 
     
     
         16 . A method according to  claim 15 , wherein said first and second core precursor species are separate entities contained in said core precursor composition, and said conversion is effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticle core. 
     
     
         17 . A method according to  claim 15 , wherein said first and second core precursor species are combined in a single entity contained in said core precursor composition. 
     
     
         18 . A method according to  claim 14 , wherein conversion of the core precursor composition to the nanoparticle core is effected in a reaction medium and said nanoparticle core is isolated from said reaction medium prior to deposition of the first layer. 
     
     
         19 . A method according to  claim 14 , wherein deposition of said first layer comprises effecting conversion of a first semiconductor material precursor composition to said first semiconductor material. 
     
     
         20 . A method according to  claim 19 , wherein said first semiconductor material precursor composition comprises third and fourth precursor species containing the ions to be incorporated into the growing first layer of the nanoparticle. 
     
     
         21 . A method according to  claim 20 , wherein said third and fourth precursor species are separate entities contained in said first semiconductor material precursor composition. 
     
     
         22 . A method according to  claim 20 , wherein said third and fourth precursor species are combined in a single entity contained in said first semiconductor material precursor composition. 
     
     
         23 . A method according to  claim 14 , wherein deposition of said second layer comprises effecting conversion of a second semiconductor material precursor composition to said second semiconductor material. 
     
     
         24 . A method according to  claim 23 , wherein said second semiconductor material precursor composition comprises fifth and sixth precursor species containing the ions to be incorporated into the growing second layer of the nanoparticle. 
     
     
         25 . A method according to  claim 24 , wherein said fifth and sixth precursor species are separate entities contained in said second semiconductor material precursor composition. 
     
     
         26 . A method according to  claim 24 , wherein said fifth and sixth precursor species are combined in a single entity contained in said second semiconductor material precursor composition. 
     
     
         27 . A nanoparticle comprising a core comprising a core semiconductor material, a first layer comprising a first semiconductor material provided on said core and a second layer comprising a second semiconductor material provided on said first layer, said core semiconductor material being different to said first semiconductor material and said first semiconductor material being different to said second semiconductor material, said nanoparticle produced according to a method comprising:
 effecting conversion of a nanoparticle core precursor composition to the material of the nanoparticle core,   depositing said first layer on said core and depositing said second layer on said first layer, said core precursor composition comprising a first precursor species containing a first ion to be incorporated into the growing nanoparticle core and a separate second precursor species containing a second ion to be incorporated into the growing nanoparticle core,   said conversion being effected in the presence of a molecular cluster compound under conditions permitting seeding and growth of the nanoparticle core.   
     
     
         28 . A nanoparticle according to  claim 27 , wherein:
 a. at least two of the core, first shell and second shell materials incorporate ions from groups 12 and 15 of the periodic table, groups 14 and 16 of the periodic table, or groups 11, 13 and 16 of the periodic table; or   b. the second shell material incorporates ions of at least two different elements from group 12 of the periodic table and ions from group 16 of the periodic table; or   c. at least one of the core, first and second semiconductor materials incorporates ions from groups 11, 13 and 16 of the periodic table and at least one other of the core, first and second semiconductor materials is a semiconductor material not incorporating ions from groups 11, 13 and 16 of the periodic table.