Synthesis, capping and dispersion of nanocrystals
Preparation of semiconductor nanocrystals and their dispersions in solvents and other media is described. The nanocrystals described herein have small (1-10 nm) particle size with minimal aggregation and can be synthesized with high yield. The capping agents on the as-synthesized nanocrystals as well as nanocrystals which have undergone cap exchange reactions result in the formation of stable suspensions in polar and nonpolar solvents which may then result in the formation of high quality nanocomposite films.
1. A solvothermal method of making nanocrystals comprising
dissolving or mixing at least one precursor of said nanocrystals in at least one solvent to produce a solution, and
heating said solution to a temperature in the range of greater than a temperature of 250° C. to a temperature of 350° C. to form said nanocrystals,
wherein
said at least one solvent additionally includes water, and
said nanocrystals are comprised of at least one of hafnium oxide, zirconium oxide, hafnium-zirconium oxide and titanium-zirconium oxide, and
wherein said precursor is selected from the group consisting of at least one of an alkoxide, an acetate, an acetylacetonate, and a halide,
such that when said nanocrystals consists of zirconium oxide, said precursor is not a chloride.
2. The method of claim 1 wherein said nanocrystals are capped with at least one agent to increase the solubility or dispersibility of said nanocrystals.
3. The method of claim 2 wherein said at least one agent comprises at least one organosilane, organocarboxylic acid or organoalcohol.
4. The method of claim 2 wherein said at least one agent to cap said nanocrystals is included in the solution.
5. The method of claim 4 wherein said at least one agent to cap said nanocrystals is contacted with said solution prior, during or after said reacting.
6. The method of claim 1 further comprising purifying and/or separating said nanocrystals.
7. The method of claim 6 further comprising capping said purified and/or separated nanocrystals with at least one capping agent to produce at least partially capped nanocrystals.
8. The method of claim 7 further comprising purifying and/or separating said at least partially capped nanocrystals.
9. The method of claim 6 further comprising contacting said purified and/or separated nanocrystals with a solvent.
10. The method of claim 8 further comprising contacting said at least partially capped nanocrystals with a solvent.
11. The method of claim 6 wherein said nanocrystals are dispersed in a further material.
12. The method of claim 11 wherein said further material is a polymer.
13. Nanocrystals formed by a method of claim 1 .
14. A method of forming a film or coating comprising dispersing the nanocrystals of claim 13 in a further material to form a dispersion, and applying said dispersion to a surface.
15. The method of claim 14 wherein said applying comprises spin coating, spraying, dipping, screen printing, rolling, painting, printing, ink jet printing, depositing by evaporation and/or vapor deposition.
16. A method of forming a nanocomposite comprising combining the nanocrystals of claim 13 with a further material and forming the nanocomposite.
17. The method of claim 1 wherein said at least one solvent comprises benzyl alcohol, phenol, oleyl alcohol, toluene, butanol, propanol, isopropanol, ethanol, methanol, propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), and 2-propoxy-propanol (PnP), acetonitrile, acetone, tetrahydrofuran, cyclic ketones and mixtures thereof.
18. The method of claim 2 wherein said at least one agent comprises at least one of n-propyltrimethoxysilane, n-propyltriethoxysilane, n-octyltrimethoxysilane, n-octyltriethoxysilane, phenytrimethoxysilane, 2-[methoxy(polyethyleneoxy)propyl]-trimethoxysilane, methoxytri(ethyleneoxy)propyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-(methacryloyloxy)propyl trimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, and glycidoxypropyltrimethoxysilane, heptanol, hexanol, octanol, benzyl alcohol, phenol, ethanol, propanol, butanol, oleylalcohol, dodecylalcohol, octadecanol and triethylene glycol monomethyl ether, octanoic acid, acetic acid, propionic acid, 2-[2-(2-methoxyethoxyl)ethoxy]acetic acid, oleic acid, benzoic acid or a mixture thereof.
19. The method of claim 11 wherein said further material comprises a fluoroplastic, a polyacrylate (Acrylic), a polyamide (PA or Nylon), a polyamide-imide (PAI), a polyketone (PK), a polyester, a polyimide (PI), a polysulfone (PSU), a polyurethane (PU), a spin-on-glass (SOG) polymer, a silicone, or mixtures thereof.
20. The method of claim 1 wherein said water is present at a molar ratio of water to precursor in a range from 1:1 to 4:1.
21. The method of claim 20 wherein said nanocrystals are in the average size range of 1 nm to 5 nm.
22. At least partially capped nanocrystals formed by a method of claim 7 .
23. A method of forming a film or coating comprising dispersing the at least partially capped nanocrystals of claim 22 in a further material to form a dispersion, and applying said dispersion to a surface.
24. The method of claim 23 wherein said applying comprises spin coating, spraying, dipping, screen printing, rolling, painting, printing, ink jet printing, depositing by evaporation and/or vapor deposition.
25. A method of forming a nanocomposite comprising combining the at least partially capped nanocrystals of claim 22 with a further material and forming the nanocomposite.
26. The method of claim 7 wherein said at least partially capped nanocrystals are dispersed in a further material.
27. The method of claim 26 wherein said further material is a polymer.
28. The method of claim 26 wherein said further material comprises a fluoroplastic, a polyacrylate (Acrylic), a polyamide (PA or Nylon), a polyamide-imide (PAI), a polyketone (PK), a polyester, a polyimide (PI), a polysulfone (PSU), a polyurethane (PU), a spin-on-glass (SOG) polymer, a silicone or mixtures thereof.
29. The method of claim 9 wherein said solvent comprises benzyl alcohol, phenol, oleyl alcohol, toluene, butanol, propanol, isopropanol, ethanol, methanol, propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), and 2-propoxy-propanol (PnP), acetonitrile, acetone, tetrahydrofuran, cyclic ketones and mixtures thereof.
30. The method of claim 10 wherein solvent comprises benzyl alcohol, phenol, oleyl alcohol, toluene, butanol, propanol, isopropanol, ethanol, methanol, propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), and 2-propoxy-propanol (PnP), acetonitrile, acetone, tetrahydrofuran, cyclic ketones and mixtures thereof.
31. The method of claim 2 further comprising purifying and/or separating said nanocrystals.
32. The method of claim 31 further comprising contacting said purified and/or separated nanocrystals with a solvent.
33. The method of claim 32 wherein said solvent comprises benzyl alcohol, phenol, oleyl alcohol, toluene, butanol, propanol, isopropanol, ethanol, methanol, propylene glycol monomethyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), ethyl lactate (EL), and 2-propoxy-propanol (PnP), acetonitrile, acetone, tetrahydrofuran, cyclic ketones and mixtures thereof.
34. The method of claim 31 wherein said nanocrystals are dispersed in a further material.
35. The method of claim 34 wherein said further material comprises a fluoroplastic, a polyacrylate (Acrylic), a polyamide (PA or Nylon), a polyamide-imide (PAI), a polyketone (PK), a polyester, a polyimide (PI), a polysulfone (PSU), a polyurethane (PU), a spin-on-glass (SOG) polymer, a silicone or mixtures thereof.
36. The method of claim 11 wherein said further material comprises poly(acrylonitrile-butadiene-styrene) (ABS), poly(methyl methacrylate) (PMMA), celluloid, cellulose acetate, poly(ethylene-vinyl acetate) (EVA), poly(ethylene vinyl alcohol) (EVOH), polyacrylonitrile (PAN), polyaryletherketone (PAEK), polybutadiene (PBD), polybutylene (PB), polybutylene terephthalate (PBT), polycaprolactone (PCL), polychlorotrifluoroethylene (PCTFE), polyethylene terephthalate (PET), polycyclohexylene dimethylene terephthalate (PCT), polycarbonate (PC), polyhydroxyalkanoates (PHAs), polyethylene (PE), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyethersulfone (PES), polyethylenechlorinates (PEC), polylactic acid (PLA), polymethylpentene (PMP), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyphthalamide (PPA), polypropylene (PP), polystyrene (PS), polytrimethylene terephthalate (PTT), polyvinyl acetate (PVA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), poly(styrene-acrylonitrile) (SAN), a Siloxane-spin-on polymer, Polydimethylsiloxane (PDMS) or polymethylphenylsiloxane, or mixtures thereof.
37. The method of claim 26 wherein said further material comprises poly(acrylonitrile-butadiene-styrene) (ABS), poly(methyl methacrylate) (PMMA), celluloid, cellulose acetate, poly(ethylene-vinyl acetate) (EVA), poly(ethylene vinyl alcohol) (EVOH), polyacrylonitrile (PAN), polyaryletherketone (PAEK), polybutadiene (PBD), polybutylene (PB), polybutylene terephthalate (PBT), polycaprolactone (PCL), polychlorotrifluoroethylene (PCTFE), polyethylene terephthalate (PET), polycyclohexylene dimethylene terephthalate (PCT), polycarbonate (PC), polyhydroxyalkanoates (PHAs), polyethylene (PE), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyethersulfone (PES), polyethylenechlorinates (PEC), polylactic acid (PLA), polymethylpentene (PMP), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyphthalamide (PPA), polypropylene (PP), polystyrene (PS), polytrimethylene terephthalate (PTT), polyvinyl acetate (PVA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), poly(styrene-acrylonitrile) (SAN), a Siloxane-spin-on polymer, Polydimethylsiloxane (PDMS) or polymethylphenylsiloxane, or mixtures thereof.
38. The method of claim 34 wherein said further material comprises poly(acrylonitrile-butadiene-styrene) (ABS), poly(methyl methacrylate) (PMMA), celluloid, cellulose acetate, poly(ethylene-vinyl acetate) (EVA), poly(ethylene vinyl alcohol) (EVOH), polyacrylonitrile (PAN), polyaryletherketone (PAEK), polybutadiene (PBD), polybutylene (PB), polybutylene terephthalate (PBT), polycaprolactone (PCL), polychlorotrifluoroethylene (PCTFE), polyethylene terephthalate (PET), polycyclohexylene dimethylene terephthalate (PCT), polycarbonate (PC), polyhydroxyalkanoates (PHAs), polyethylene (PE), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyethersulfone (PES), polyethylenechlorinates (PEC), polylactic acid (PLA), polymethylpentene (PMP), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyphthalamide (PPA), polypropylene (PP), polystyrene (PS), polytrimethylene terephthalate (PTT), polyvinyl acetate (PVA), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), poly(styrene-acrylonitrile) (SAN), a Siloxane-spin-on polymer, Polydimethylsiloxane (PDMS) or polymethylphenylsiloxane, or mixtures thereof.
39. The method of claim 1 wherein said precursor is selected from the group consisting of zirconium ethoxide (Zr(OCH 2 CH 3 ) 4 ), zirconium n-propoxide (Zr(OCH 2 CH 2 CH 3 ) 4 ), zirconium isopropoxide (Zr(OCH(CH 3 ) 2 ) 4 ), zirconium n-butoxide (Zr(OCH 2 CH 2 CH 2 CH 3 ) 4 ), zirconium t-butoxide (Zr(OC(CH 3 ) 3 ) 4 ), hafnium ethoxide (Hf(OCH 2 CH 3 ) 4 ), hafnium n-propoxide (Hf(OCH 2 CH 2 CH 3 ) 4 ), hafnium isopropoxide (Hf(OCH(CH 3 ) 2 ) 4 ), hafnium butoxide (Hf(OCH 2 CH 2 CH 2 CH 3 ) 4 ), hafnium t-butoxide (Hf(OC(CH 3 ) 3 ) 4 ), titanium ethoxide (Ti(OCH 2 CH 3 ) 4 ), titanium n-propoxide (Ti(OCH 2 CH 2 CH 3 ) 4 ), titanium isopropoxide (Ti(OCH(CH 3 ) 2 ) 4 ), titanium t-butoxide Ti(OC(CH 3 ) 3 ) 4 ), titanium n-butoxide (Ti(OCH 2 CH 2 CH 2 CH 3 ) 4 ), zirconium acetate (Zr(OOCCH 3 ) 4 ), zirconium acetylacetonate (Zr(CH 3 COCHCOCH 3 ) 4 ), hafnium acetate (Hf(OOCCH 3 ) 4 ), zirconium chloride (ZrCl 4 ), zirconium fluoride (ZrF 4 ), zirconium iodide (Zr 14 ), zirconium bromide (ZrBr 4 ), hafnium bromide (HfBr 4 ), hafnium chloride (HfC 14 ), hafnium iodide (Hf 14 ), titanium chloride (TiCl 4 ), titanium bromide (TiBr 4 ), titanium iodide (TiI 4 ), and titanium fluoride (TiF 4 ).