Nanocrystal-metal oxide-polymer composites and preparation method thereof

Abstract

Nanocrystal-metal oxide-polymer composites and their methods of preparation are described. The composites comprises a number of nanocrystals within a metal oxide matrix, and an oligomer or polymer covalently bonded to organic reactive groups of the metal oxide matrix. The composites can be applied to a variety of electronic devices. The electronic devices constructed from the composites do not decrease in performance rapidly due to degradation and exhibit improved stability.

1 . A nanocrystal- metal oxide composite comprising
 a nanocrystal surface-modified with a surfactant and   a metal oxide surrounding the nanocrystal   wherein the nanocrystal- metal oxide composite is repassivated with an oligomer or a polymer.   
     
     
         2 . The composite of  claim 1 ,
 wherein the surfactant has at least one reactive group selected from —SR1, —NR1R2, —OR1, —COOR1, —PR1R2, —P(═O)R1R2, —SiR1R2R3 and —C(═O)R1 (1) (R1R2 and R3, which may be the same or different, each represents H, C6-C24 alkyl, C6-C24 alkenyl, C6-C24 aryl or C6-C24 alkoxy.).   
     
     
         3 . The composite of  claim 1 ,
 wherein the nanocrystal is at least one compound selected from the group consisting of metals, Group II-VI compounds, Group II-V compounds, Group III-VI compounds, Group III-V compounds, Group IV-VI compounds, Group compounds, Group II-IV-VI compounds, Group II-IV-V compounds and Group IV compounds; and alloys thereof.   
     
     
         4 . The composite of  claim 1 ,
 wherein the nanocrystal has a core, a core-shell, a core-multishell, a core-intermediate layer-shell, a core-alloy layer-shell, a core-intermediate layer-multishell, or a core-alloy layer-multishell structure.   
     
     
         5 . The composite of  claim 4 ,
 wherein the nanocrystal has a shell composed of a large band gap material.   
     
     
         6 . The composite of  claim 5 ,
 wherein the nanocrystal has a core comprising at least one selected from CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, GaN, GaP, GaAs, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, SiC, Fe, Pt, Ni, Co, Al, Ag, Au, Cu, FePt, Si, Ge, PbS, PbSe and PbTe and alloys or combinations thereof; and a shell comprising ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, AlN, Alp, AlAs, AlSb, GaN, GaP, GaAs, GaSb, GaSe, InN, InP, InAs, InSb, TlN, TlP, TlAs, TlSb, PbS, PbSe and PbTe and alloys or combinations thereof.   
     
     
         7 . The composite of  claim 1 ,
 wherein the metal oxide is formed by crosslinking of a metal oxide precursor.   
     
     
         8 . The composite of  claim 7 ,
 wherein the metal oxide precursor comprises at least one selected from the group consisting of metal alkoxides, metal halides and metal hydroxides.   
     
     
         9 . The composite of  claim 8 ,
 wherein the metal alkoxides comprises at least one selected from the group consisting of titanium methoxide, titanium ethoxide, titanium isopropoxide, titanium butoxide, zinc methoxide, zinc ethoxide, zinc isopropoxide, zinc butoxide, tetramethylorthosilicate, tetraethylorthosilicate, silicon tetraisopropoxide, silicon tetrabutoxide, trimethoxysilane, triethoxysilane, mercaptopropyltrimethoxysilane, mercaptopropyltriethoxysilane, aminopropyltrimethoxysilane, aminopropyltriethoxysilane, tin methoxide, tin ethoxide, tin isopropoxide, tin butoxide, tungsten methoxide, tungsten ethoxide, tungsten isopropoxide, tungsten butoxide, tantalum methoxide, tantalum ethoxide, tantalum isopropoxide, tantalum butoxide, barium methoxide, barium ethoxide, barium isopropoxide, barium butoxide, zirconium methoxide, zirconium ethoxide, zirconium isopropoxide, zirconium butoxide, aluminum methoxide, aluminum ethoxide, aluminum isopropoxide, aluminum butoxide, yttrium methoxide, yttrium ethoxide, yttrium isopropoxide, yttrium butoxide, iron methoxide, iron ethoxide, iron isopropoxide, iron butoxide, cesium methoxide, cesium ethoxide, cesium isopropoxide, cesium butoxide, chromium methoxide, chromium ethoxide, chromium isopropoxide, and chromium butoxide.   
     
     
         10 . The composite of  claim 8 ,
 wherein metal halides comprises at least one selected from the group consisting of titanium chloride, zinc chloride, silicon tetrachloride, tin chloride, tungsten chloride, tantalum chloride, barium chloride, zirconium chloride, hafnium chloride, aluminum chloride, yttrium chloride, iron (II) chloride, iron (III) chloride, cesium chloride, chromium chloride, titanium bromide, zinc bromide, silicon tetrabromide, tin bromide, tungsten bromide, tantalum bromide, barium bromide, zirconium bromide, hafnium bromide, aluminum bromide, yttrium bromide, iron (II) bromide, iron (III) bromide, cesium bromide, chromium bromide, titanium iodide, zinc iodide, silicon tetraiodide, tin iodide, tungsten iodide, tantalum iodide, barium iodide, zirconium iodide, hafnium iodide, aluminum iodide, yttrium iodide, iron (II) iodide, iron (III) iodide, cesium iodide, and chromium iodide.   
     
     
         11 . The composite of  claim 8 ,
 wherein the metal hydroxides comprises at least one selected from the group consisting of titanium hydroxide, zinc hydroxide, silicon hydroxide, tin hydroxide, tungsten hydroxide, tantalum hydroxide, barium hydroxide, zirconium hydroxide, hafnium hydroxide, aluminum hydroxide, yttrium hydroxide, iron (II) hydroxide, iron (III) hydroxide, cesium hydroxide, and chromium hydroxide.   
     
     
         12 . The composite of  claim 1 ,
 wherein the metal oxide is selected from the group consisting of TiO 2 , ZnO, SiO 2 , SnO 2 , WO 3 , Ta 2 O 3 , BaTiO 3 , BaZrO 3 , ZrO 2 , HfO 2 , Al 2 O 3 , Y 2 O 3 , ZrSiO 4 , Fe 2 O 3 , Fe 3 O 4 , CeO and CrO 3 ; and  mixtures thereof.   
     
     
         13 . The composite of  claim 1 ,
 wherein the concentration of the nanocrystal in the nanocrystal-metal oxide is in the range of 0.01 to 20 vol %.   
     
     
         14 . The composite of  claim 1 ,
 wherein the oligomer or the polymer is a polymerized product of at least one selected from the group consisting of alkyl methacrylates, styrene, acrylic acid, esters, olefins, alkyl alcohols, alkyl carboxylic acids, alkylamines, amino acids, and isocyanates.   
     
     
         15 . The composite of  claim 1 ,
 wherein the polymer comprises at least one selected from the group consisting of polyacrylate, polystyrene, polyamide, polyester, polyurea, polyacrylic acid, polycarbonate, polysiloxane, polyurethane, poly(ethylene oxide) and polyolefin.   
     
     
         16 . The composite of  claim 1 ,
 wherein the polymer comprises at least one selected from the group consisting of polyacrylate, polystyrene, polyamide, polyester, polyurea, polyacrylic acid, polycarbonate, polysiloxane, polyurethane, poly(ethylene oxide) and polyolefin.   
     
     
         17 . An electronic device comprising the composite of  claim 1 . 
     
     
         18 . The electronic device of  claim 17 , wherein the device is selected from the group consisting of light emitting diodes, laser devices, memory devices, sensors, and photovoltaic devices.