Nanocomposites

Abstract

This invention provides composite materials comprising nanostructures (e.g., nanowires, branched nanowires, nanotetrapods, nanocrystals, and nanoparticles). Methods and compositions for making such nanocomposites are also provided, as are articles comprising such composites. Waveguides and light concentrators comprising nanostructures (not necessarily as part of a nanocomposite) are additional features of the invention.

1 . A method of making a composite material, the method comprising:
 preparing one or more discrete, preformed inorganic nanowires, wherein the one or more inorganic nanowires are selected from the group consisting of semiconducting inorganic nanowires and ferroelectric inorganic nanowires, which semiconducting inorganic nanowires comprise a core and at least one shell layer disposed about the core, wherein the one or more inorganic nanowires have an aspect ratio greater than about 2; and   combining the one or more inorganic nanowires with a matrix comprising at least one inorganic polymer or inorganic glass or a small molecule.   
     
     
         2 . The method of  claim 1 , wherein the one or more inorganic nanowires are included in sufficient quantity that the composite material has a dielectric constant of at least about 2, at least about 5, or at least about 10. 
     
     
         3 . The method of  claim 1 , wherein the matrix comprises an inorganic glass. 
     
     
         4 . The method of  claim 3 , wherein the inorganic glass comprises TiO 2 . 
     
     
         5 . The method of  claim 3 , wherein the inorganic glass comprises SiO 2 . 
     
     
         6 . The method of  claim 1 , wherein the matrix comprises an inorganic polymer. 
     
     
         7 . The method of  claim 1 , further comprising aligning the one or more inorganic nanowires within the matrix. 
     
     
         8 . The method of  claim 7 , wherein said aligning comprises using an electric field to align the one or more inorganic nanowires in the matrix. 
     
     
         9 . The method of  claim 1 , wherein the one or more inorganic nanowires have an aspect ratio greater than about 10. 
     
     
         10 . The method of  claim 1 , wherein the one or more inorganic nanowires comprise semiconducting inorganic nanowires which comprise a core made of silicon and one or more oxide shell layers disposed about said core. 
     
     
         11 . The method of  claim 1 , further comprising applying the composite material as a thin film to a substrate. 
     
     
         12 . The method of  claim 11 , wherein the substrate comprises a plastic substrate. 
     
     
         13 . The method of  claim 11 , wherein the substrate comprises a metal substrate. 
     
     
         14 . The method of  claim 1 , further comprising forming the composite material into a thin film within which the one or more inorganic nanowires have their long axes oriented substantially perpendicular to a surface of the film. 
     
     
         15 . The method of  claim 1 , further comprising forming the composite material into a thin film within which the one or more inorganic nanowires have their long axes oriented substantially parallel to a surface of the film. 
     
     
         16 . The method of  claim 1 , wherein the matrix has an affinity for at least a portion of a surface of the one or more inorganic nanowires. 
     
     
         17 . The method of  claim 1 , wherein the one or more inorganic nanowires each comprise at least one surface ligand, wherein the at least one surface ligand has an affinity for the matrix. 
     
     
         18 . The method of  claim 17 , wherein the at least one surface ligand comprises at least one functional group selected from the group consisting of: an amine, a phosphine, a phosphine oxide, a phosphonate, a phosphonite, a phosphonic acid, a phosphinic acid, a thiol, an alcohol, and an amine oxide. 
     
     
         19 . The method of  claim 1 , further comprising adding one or more additives to the composite material. 
     
     
         20 . The method of  claim 19 , wherein the one or more additives comprise one or more of: a surfactant, a plasticizer, a catalyst, an antioxidant, and/or a strengthening fiber. 
     
     
         21 . A method of making a composite material, the method comprising:
 preparing one or more discrete, preformed inorganic nanowires, wherein the one or more inorganic nanowires are selected from the group consisting of semiconducting inorganic nanowires and ferroelectric inorganic nanowires, which semiconducting inorganic nanowires comprise a core and at least one shell layer disposed about the core; and   combining the one or more inorganic nanowires with a matrix comprising at least one organic polymer or inorganic polymer or inorganic glass or a small molecule, wherein the matrix has an affinity for at least a portion of the one or more inorganic nanowires.   
     
     
         22 . The method of  claim 21 , wherein the one or more inorganic nanowires are included in sufficient quantity that the composite material has a dielectric constant of at least about 2, at least about 5, or at least about 10. 
     
     
         23 . The method of  claim 21 , wherein the matrix comprises an inorganic glass. 
     
     
         24 . The method of  claim 23 , wherein the inorganic glass comprises TiO 2 . 
     
     
         25 . The method of  claim 23 , wherein the inorganic glass comprises SiO 2 . 
     
     
         26 . The method of  claim 21 , wherein the matrix comprises an inorganic polymer. 
     
     
         27 . The method of  claim 21 , wherein the matrix comprises an organic polymer. 
     
     
         28 . The method of  claim 21 , further comprising aligning the one or more inorganic nanowires within the matrix. 
     
     
         29 . The method of  claim 28 , wherein said aligning comprises using an electric field to align the one or more inorganic nanowires in the matrix. 
     
     
         30 . The method of  claim 21 , wherein the one or more inorganic nanowires have an aspect ratio greater than about 10. 
     
     
         31 . The method of  claim 21 , wherein the one or more inorganic nanowires comprise semiconducting inorganic nanowires which comprise a core made of silicon and one or more oxide shell layers disposed about said core. 
     
     
         32 . The method of  claim 21 , further comprising applying the composite material as a thin film to a substrate. 
     
     
         33 . The method of  claim 32 , wherein the substrate comprises a plastic substrate. 
     
     
         34 . The method of  claim 32 , wherein the substrate comprises a metal substrate. 
     
     
         35 . The method of  claim 21 , further comprising forming the composite material into a thin film within which the one or more inorganic nanowires have their long axes oriented substantially perpendicular to a surface of the film. 
     
     
         36 . The method of  claim 21 , further comprising forming the composite material into a thin film within which the one or more inorganic nanowires have their long axes oriented substantially parallel to a surface of the film. 
     
     
         37 . The method of  claim 21 , further comprising adding one or more additives to the composite material. 
     
     
         38 . The method of  claim 37 , wherein the one or more additives comprise one or more of: a surfactant, a plasticizer, a catalyst, an antioxidant, and/or a strengthening fiber.