Blue-emitting nanocrystals with cubic shape and fluorine passivation

Abstract

The present disclosure relates to the field of nanotechnology. The present disclosure provides a method for preparing nanostructures by fluoride passivation. The present disclosure also provides a method for preparing nanostructures by fluoride and amine passivation. The nanostructures have high quantum yields, narrow emission peak widths, tunable emission wavelengths, and colloidal stability. Nanostructures prepared using the method are also provided. Nanostructure films and molded articles including the nanostructures are also provided.

Description

Technical Field

[0001]

[0001] This disclosure relates to the field of nanotechnology. This disclosure provides a method for preparing nanostructures by fluorination passivation. This disclosure also provides a method for preparing nanostructures by fluorination and amine passivation. The nanostructures have high quantum yields, narrow emission peak widths, adjustable emission wavelengths, and colloidal stability. Nanostructures prepared using this method are also provided. And nanostructured films and molded articles containing the nanostructures are also provided.

Background Art

[0002]

[0002] Semiconductor nanostructures can be incorporated into various electronic and optical devices. The electrical and optical properties of such nanostructures are diverse depending on, for example, their composition, shape, and size. For example, the size-tunable properties of semiconductor nanoparticles are of great interest for applications such as light-emitting diodes (LEDs) and liquid crystal displays (LCDs). Highly emissive nanostructures are particularly desirable for such applications.

[0003]

[0003] The steric volume of long-chain alkyl ligands can lead to insufficient ligand coverage on the surface of semiconductor nanocrystals due to packing limitations. Similarly, the surface of spherical particles exhibits steps, depressions, and twists that may make ligand passivation difficult. Such unpassivated sites on the surface of quantum dots can lead to intermediate gap states that act as hole traps when a potential is applied across the quantum dot. Holes will accumulate at the HTL-QD interface, leading to an increase in the operating voltage and irreversible electrochemical decomposition.

[0004]

[0004] Combinations of native ligands for most quantum dots (e.g., carboxylates and phosphines) are hydrophobic and thus quantum dots containing these native ligands are not soluble in a wide range of organic media and are incompatible with matrix materials commonly used in the preparation of quantum dot films. Ligand exchange can be used to solve these problems, but the exchange can affect surface trap states and thus the photoluminescence quantum yield of the quantum dots. For example, metal carboxylate complexes can be readily substituted from carboxylate-terminated ME complexes (ME = CdSe, CdS, PbSe or PbS) using various Lewis bases (Anderson, N.C., et al., J. Am. Chem. Soc. 135: 18536-18548 (2013)). However, removal of up to 90% of the surface-bound Cd(O2CR)2 (R = oleyl or tetradecyl) from CdSe and CdS nanocrystals results in a decrease in the photoluminescence quantum yield from 10% to <1% for CdSe nanocrystals and from 20% to <1% for CdS nanocrystals. Thus, it has been found that not only are they non-linearly independent, but also that the photoluminescence quantum yield and conjugation are not simply related because Cd(O2CR)2 can be simultaneously substituted by amine bonds.

[0005]

[0005] There is a need to produce nanostructures having high quantum yields, narrow emission peak widths, tunable emission wavelengths and colloidal stability.

Summary of the Invention

[0006]

[0006] In some embodiments, the present disclosure provides a nanostructure comprising a core comprising a nanocrystal core; and at least one shell disposed on the core and comprising ZnS and a fluoride.

[0007]

[0007] In some embodiments, the core comprises ZnSe, ZnSeTe, InP or InAs. In some embodiments, the core is ZnSe1-x Te x (where 0 ≦ x < 1).

[0008]

[0008] In some embodiments, the nanostructure includes two shells. In some embodiments, at least one shell includes ZnSe. In some embodiments, at least one shell includes ZnSe and a fluoride. In some embodiments, at least one shell includes a first shell including ZnSe, and a second shell including ZnS and a fluoride. In some embodiments, at least one shell includes a first shell including ZnSe and a fluoride, and a second shell including ZnS and a fluoride.

[0009]

[0009] In some embodiments, the fluoride is in the form of a metal fluoride, ammonium fluoride or tetraalkylammonium fluoride. In some embodiments, the fluoride is in the form of a metal fluoride including ZnF2, HfF4 or ZrF4. In some embodiments, the metal fluoride is ZnF2.

[0010]

[0010] In some embodiments, at least one shell includes ZnS and ZnF2. In some embodiments, at least one shell includes ZnSe and ZnF2.

[0011]

[0011] In some embodiments, the fluoride is in the form of a tetraalkylammonium fluoride, including tetrabutylammonium fluoride, tetrapropylammonium fluoride, diisopropyldimethylammonium fluoride, tetraethylammonium fluoride, and tetramethylammonium fluoride, dioctadecyldimethylammonium fluoride, dihexadecyldimethylammonium fluoride, ditetradecyldimethylammonium fluoride, didodecyldimethylammonium fluoride, didecyldimethylammonium fluoride, dioctyldimethylammonium fluoride, bis(ethylhexyl)dimethylammonium fluoride, octadecyltrimethylammonium fluoride, oleyltrimethylammonium fluoride, hexadecyltrimethylammonium fluoride, tetradecyltrimethylammonium fluoride, dodecyltrimethylammonium fluoride, decyltrimethylammonium fluoride, octyltrimethylammonium fluoride, phenylethyltrimethylammonium fluoride, benzyltrimethylammonium fluoride, phenyltrimethylammonium fluoride, benzylhexadecyldimethylammonium fluoride, benzyltetradecyldimethylammonium fluoride, benzyldodecyldimethylammonium fluoride, benzyldecyldimethylammonium fluoride, benzyloctyldimethylammonium fluoride, benzyltributylammonium fluoride, or benzyltriethylammonium fluoride. In some embodiments, the tetraalkylammonium fluoride is tetrabutylammonium fluoride.

[0012]

[0012] In some embodiments, the molar ratio of the fluoride bound to the nanostructure to zinc in the nanostructure is from about 0.05 to about 0.33.

[0013]

[0013] In some embodiments, the molar ratio of the fluoride bound to the nanostructure to zinc in the nanostructure is about 0.13. In some embodiments, the molar ratio of the fluoride bound to the nanostructure to zinc in the nanostructure is about 0.32.

[0014]

[0014] In some embodiments, the nanostructure further comprises a solvent. In some embodiments, the solvent is a nonpolar solvent. In some embodiments, the nonpolar solvent includes hexane, heptane, octane, toluene, or a mixture thereof. In some embodiments, the nonpolar solvent is octane. In some embodiments, the nonpolar solvent is hexane.

[0015]

[0015] In some embodiments, the nanostructure exhibits a photoluminescence quantum yield of about 60% to about 99%. In some embodiments, the nanostructure exhibits a photoluminescence quantum yield of about 70% to about 99%.

[0016]

[0016] In some embodiments, the nanostructure includes a core containing ZnSe, and at least one shell containing ZnS and ZnF2. In some embodiments, the nanostructure includes a core containing ZnSe, at least one shell containing ZnSe, and at least one shell containing ZnS and ZnF2. In some embodiments, the nanostructure includes a core containing ZnSe, at least one shell containing ZnSe and ZnF2, and at least one shell containing ZnS and ZnF2. In some embodiments, the nanostructure includes ZnSe 1-x Te x (where 0 ≦ x < 1), and at least one shell containing ZnS and ZnF2. In some embodiments, the nanostructure includes ZnSe 1-x Te x (where 0 ≦ x < 1), a core containing at least one shell containing ZnSe, and at least one shell containing ZnS and ZnF2. In some embodiments, the nanostructure includes ZnSe 1-x Te x (where 0 ≦ x < 1), a core containing at least one shell containing ZnSe and ZnF2, and at least one shell containing ZnS and ZnF2.

[0017]

[0017] In some embodiments, the nanostructure is a quantum dot. In some embodiments, the nanostructure is substantially cubic.

[0018]

[0018] In some embodiments, the present disclosure provides a nanostructure by (a) providing a nanocrystal core; (b) optionally, mixing the core of (a) with a zinc source and a selenium source to provide a core having a ZnSe shell; (c) mixing the core of (a) or the core having a ZnSe shell of (b) with a fluoride source; and (d) leaching a solution containing a zinc source and a sulfur source into the mixture of (c) to provide a method for preparing a nanostructure.

[0019]

[0019] In some embodiments, the core comprises ZnSe, ZnSeTe, InP or InAs. In some embodiments, the core is ZnSe 1-x Te x (where 0 ≦ x < 1). In some embodiments, the core comprises ZnSe.

[0020]

[0020] In some embodiments, the mixing in (b) is at a temperature of about 250 °C to about 350 °C. In some embodiments, the mixing in (b) is at a temperature of about 310 °C.

[0021]

[0021] In some embodiments, the mixing in (b) comprises mixing the core of (a) with a zinc source, a selenium source and optionally a fluoride source to provide a core having a shell containing ZnSe and fluoride. In some embodiments, the fluoride source comprises a metal fluoride, NH4F or tetraalkylammonium fluoride. In some embodiments, the fluoride source is a metal fluoride comprising ZnF2, HfF4 or ZrF4. In some embodiments, the fluoride source is ZnF2.

[0022]

[0022] In some embodiments, the mixing in (c) is at a temperature of about 70 °C to about 130 °C. In some embodiments, the mixing in (c) is at a temperature of about 100 °C.

[0023]

[0023] In some embodiments, the leaching in (d) is at a temperature of about 250 °C to about 350 °C. In some embodiments, the leaching in (d) is at a temperature of about 310 °C.

[0024]

[0024] In some embodiments, the leaching in (d) is at a leaching rate of about 0.05 mL / min to about 2.0 mL / min. In some embodiments, the leaching in (d) is at a leaching rate of about 0.1 mL / min.

[0025]

[0025] In some embodiments, the selenium source in (b) includes trioctylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, cyclohexylphosphine selenide, octaselenol, dodecaselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl)selenide, or a mixture thereof. In some embodiments, the selenium source in (b) is trioctylphosphine selenide.

[0026]

[0026] In some embodiments, the zinc source in (b) includes diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source in (b) is zinc oleate.

[0027]

[0027] In some embodiments, the fluoride source of (c) includes a metal fluoride, NH4F, or tetraalkylammonium fluoride. In some embodiments, the fluoride source of (c) is a metal fluoride including ZnF2, HfF4, or ZrF4. In some embodiments, the fluoride source of (c) is ZnF2.

[0028]

[0028] In some embodiments, the zinc source of (d) includes diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source of (d) is zinc oleate.

[0029]

[0029] In some embodiments, the sulfur source of (d) includes trioctylphosphine sulfide, elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide, or a combination thereof. In some embodiments, the sulfur source of (d) is trioctylphosphine sulfide.

[0030]

[0030] In some embodiments, the present disclosure provides a nanostructure including a core including ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride; and at least one shell including ZnS and optionally a second metal fluoride disposed on the core.

[0031]

[0031] In some embodiments, the core comprises ZnSe. In some embodiments, the core is ZnSe 1-x Te x (where 0 ≦ x < 1).

[0032]

[0032] In some embodiments, the nanostructure comprises two shells.

[0033]

[0033] In some embodiments, the first metal fluoride comprises ZnF2, HfF4 or ZrF4. In some embodiments, the first metal fluoride is ZrF4.

[0034]

[0034] In some embodiments, the second metal fluoride comprises ZnF2, HfF4 or ZrF4. In some embodiments, the second metal fluoride is ZrF4.

[0035]

[0035] In some embodiments, at least one shell comprises ZnS and ZrF4.

[0036]

[0036] In some embodiments, the molar ratio of the fluoride of the nanostructure to zinc in the nanostructure is from about 0.05 to about 0.35.

[0037]

[0037] In some embodiments, the nanostructure further comprises a solvent. In some embodiments, the solvent is a nonpolar solvent. In some embodiments, the nonpolar solvent comprises hexane, heptane, octane, toluene or a mixture thereof. In some embodiments, the nonpolar solvent is octane. In some embodiments, the nonpolar solvent is hexane.

[0038]

[0038] In some embodiments, the nanostructure exhibits a photoluminescence quantum yield of about 60% to about 99%. In some embodiments, the nanostructure exhibits a photoluminescence quantum yield of about 70% to about 99%.

[0039]

[0039] In some embodiments, the nanostructure includes a core comprising ZnSe and a metal fluoride comprising ZnF2, HfF4, or ZrF4; and at least one shell comprising ZnS and a metal fluoride comprising ZnF2, HfF4, or ZrF4.

[0040]

[0040] In some embodiments, the nanostructure includes a core comprising ZnSe and a metal fluoride comprising ZnF2, HfF4, or ZrF4; at least one shell comprising ZnSe; and at least one shell comprising ZnS and a metal fluoride comprising ZnF2, HfF4, or ZrF4.

[0041]

[0041] In some embodiments, the nanostructure includes a core comprising ZnSe and a metal fluoride comprising ZnF2, HfF4, and ZrF4; and at least one shell comprising ZnS.

[0042]

[0042] In some embodiments, the nanostructure includes a core comprising ZnSe and a metal fluoride comprising ZnF2, HfF4, or ZrF4; at least one shell comprising ZnSe; and at least one shell comprising ZnS.

[0043]

[0043] In some embodiments, the nanostructure is ZnSe 1-x Te x (where 0 < x < 1) and a core comprising a metal fluoride comprising ZnF2, HfF4, or ZrF4; and at least one shell comprising ZnS and a metal fluoride comprising ZnF2, HfF4, or ZrF4.

[0044]

[0044] In some embodiments, the nanostructure is ZnSe 1-x Te x (where 0 < x < 1) and a core comprising a metal fluoride comprising ZnF2, HfF4, or ZrF4; at least one shell comprising ZnSe; and at least one shell comprising ZnS and a metal fluoride comprising ZnF2, HfF4, or ZrF4.

[0045]

[0045] In some embodiments, the nanostructure is ZnSe 1-x Te x (where 0 < x < 1) and a core comprising a metal fluoride including ZnF2, HfF4, or ZrF4; and at least one shell comprising ZnS.

[0046]

[0046] In some embodiments, the nanostructure is ZnSe 1-x Te x (where 0 < x < 1) and a core comprising a metal fluoride including ZnF2, HfF4, or ZrF4; at least one shell comprising ZnSe; and at least one shell comprising ZnS.

[0047]

[0047] In some embodiments, the nanostructure is a quantum dot.

[0048]

[0048] In some embodiments, the nanostructure is substantially cubic.

[0049]

[0049] In some embodiments, the present disclosure provides a nanostructure by (a) mixing a solution of a zinc source, a selenium source, and a first metal fluoride source to provide a core comprising ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and the first metal fluoride; (b) optionally, mixing the core of (a) with a zinc source and a selenium source to provide a core having a ZnSe shell; (c) optionally, mixing the core of (a) or the core having a ZnSe shell of (b) with a second metal fluoride source; and (d) leaching a solution comprising a zinc source and a sulfur source into the mixture of (a), (b), or (c) to provide a method for preparing a nanostructure.

[0050]

[0050] In some embodiments, the mixing in (a) is at a temperature of about 20°C to about 120°C. In some embodiments, the mixing in (a) is at a temperature of about 100°C.

[0051]

[0051] In some embodiments, the mixing in (b) is at a temperature of about 250°C to about 350°C. In some embodiments, the mixing in (b) is at a temperature of about 310°C.

[0052]

[0052] In some embodiments, the mixing in (c) is at a temperature of about 20°C to about 120°C. In some embodiments, the mixing in (c) is at a temperature of about 100°C.

[0053]

[0053] In some embodiments, the leaching in (d) is at a temperature of about 250°C to about 350°C. In some embodiments, the leaching in (d) is at a temperature of about 310°C.

[0054]

[0054] In some embodiments, the leaching in (d) is at a leaching rate of about 0.05 mL / min to about 5.0 mL / min. In some embodiments, the leaching in (d) is at a leaching rate of about 0.5 mL / min.

[0055]

[0055] In some embodiments, the selenium source in (a) includes trioctylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, cyclohexylphosphine selenide, octaselenol, dodecaselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl)selenide, or a mixture thereof. In some embodiments, the selenium source in (a) is trioctylphosphine selenide.

[0056]

[0056] In some embodiments, the zinc source of (a) includes diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate or a mixture thereof. In some embodiments, the zinc source of (a) is zinc oleate.

[0057]

[0057] In some embodiments, the first metal fluoride of (a) includes ZnF2, HfF4 or ZrF4. In some embodiments, the first metal fluoride source of (a) is ZnF2. In some embodiments, the first metal fluoride source of (a) is HfF4. In some embodiments, the first metal fluoride source of (a) is ZrF4.

[0058]

[0058] In some embodiments, the zinc source of (b) includes diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate or a mixture thereof. In some embodiments, the zinc source of (b) is zinc oleate.

[0059]

[0059] In some embodiments, the selenium source of (b) includes trioctylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, cyclohexylphosphine selenide, octaselenol, dodecaselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl)selenide, or a mixture thereof. In some embodiments, the selenium source of (b) is trioctylphosphine selenide.

[0060]

[0060] In some embodiments, the second metal fluoride of (c) includes ZnF2, HfF4, or ZrF4. In some embodiments, the second metal fluoride source of (c) is ZnF2. In some embodiments, the second metal fluoride source of (c) is HfF4. In some embodiments, the second metal fluoride source of (c) is ZrF4.

[0061]

[0061] In some embodiments, the zinc source of (d) includes diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source of (d) is zinc oleate.

[0062]

[0062] In some embodiments, the sulfur source of (d) includes trioctylphosphine sulfide, elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide or a combination thereof. In some embodiments, the sulfur source of (d) is trioctylphosphine sulfide.

[0063]

[0063] In some embodiments, the present disclosure provides a device including the nanostructures of the present disclosure. In some embodiments, the device is a display device.

[0064]

[0064] In some embodiments, the display device is a backplane; a display panel disposed on the backplane; and a patterned quantum dot layer including nanostructures disposed on the display panel including a quantum dot color converter.

[0065]

[0065] In some embodiments, the backplane includes a blue LED, an LCD, an OLED or a micro LED.

[0066]

[0066] In some embodiments, the present disclosure provides a nanostructured film including at least one population of nanostructures, wherein the nanostructures include a core including a nanocrystal core; and at least one shell disposed on the core, and at least one shell includes ZnS and a fluoride.

[0067]

[0067] In some embodiments, the present disclosure provides a nanostructured film including at least one population of nanostructures, wherein the nanostructures are ZnSe or ZnSe 1-x Te xA core containing (where 0 ≦ x < 1) and a first metal fluoride; and at least one shell containing ZnS and optionally a second metal fluoride disposed on the core are provided to form a nanostructured film.

[0068]

[0068] In some embodiments, the nanostructured film further comprises at least one organic resin. In some embodiments, the nanostructured film comprises 1 to 5 kinds of organic resins. In some embodiments, the nanostructured film comprises 1 kind of organic resin. In some embodiments, at least one organic resin is a thermosetting resin or a UV curable resin. In some embodiments, at least one organic resin is a UV curable resin.

[0069]

[0069] In some embodiments, the present disclosure provides a molded article comprising a nanostructured film.

[0070]

[0070] In some embodiments, the molded article is (a) a first barrier layer; (b) a second barrier layer; and (c) a light-emitting layer between the first barrier layer and the second barrier layer, the light-emitting layer comprising a core containing a nanocrystal core; and at least one shell containing ZnS and fluoride disposed on the core, the light-emitting layer comprising a population of nanostructures including.

[0071]

[0071] In some embodiments, the molded article is (a) a first barrier layer; (b) a second barrier layer; and (c) a light-emitting layer between the first barrier layer and the second barrier layer, which is ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a core containing a first metal fluoride; and at least one shell containing ZnS and optionally a second metal fluoride disposed on the core, the light-emitting layer comprising a population of nanostructures including.

[0072]

[0072] In some embodiments, the nanostructure is a quantum dot.

[0073]

[0073] In some embodiments, the molded article is an electroluminescent device. In some embodiments, the molded article is a light-emitting diode. In some embodiments, the molded article is a liquid crystal display.

[0074]

[0074] In some embodiments, the maximum external quantum efficiency (EQE) of the electroluminescent device is from about 1.5% to about 15%.

[0075]

[0075] In some embodiments, the maximum external quantum efficiency (EQE) of the electroluminescent device is about 5%.

[0076]

[0076] In some embodiments, the electroluminescent device reaches 50% of the initial luminance of 500 cd / m 2 (nit) after about 19 seconds to about 35 seconds.

[0077]

[0077] In some embodiments, the time (T 2 ) for the electroluminescent device to reach 50% of the initial luminance of 500 cd / m 50 (nit) is at least about three times longer than the T of an electroluminescent device containing a corresponding nanostructure that does not contain any fluoride in the shell. 50

Brief Description of the Drawings

[0078]

Figure 1

[0078] A schematic diagram of the density of the state diagram due to the intermediate-gap trap state shown as the "trap state". By complete surface coverage with halide ions, the intermediate-gap trap state is reduced, forming a better electronically balanced quantum dot.

Figure 2

[0079] A transmission electron microscope (TEM) image showing a typical quasi-spherical morphology, which is typical of ZnSe / ZnS core / shell structure quantum dots.

Figure 3

[0080] A TEM image showing an increase in the ratio of tetrahedral and cubic particles for the synthesis of ZnSe / ZnS core / shell structure quantum dots treated with 4 molar equivalents of ZnF2.

Figure 4

[0081] A TEM image showing an increase in the ratio of tetrahedral and cubic particles for the synthesis of ZnSe / ZnS core / shell structure quantum dots with 14 molar equivalents of ZnF2.

Figure 5

[0082] A TEM image showing a typical quasi-spherical morphology, which is typical of ZnSeTe / ZnSe / ZnS core / shell / shell structure quantum dots.

Figure 6

[0083] A TEM image showing an increase in the ratio of tetrahedral and cubic particles for the synthesis of ZnSeTe / ZnSe / ZnS core / shell / shell structure quantum dots using ZnF2.

Figure 7

[0084] A scatter plot of external quantum efficiency (EQE) versus luminance (nit) for standard ligand (not ZnF2) ZnSe / ZnS quantum dots (●), ZnSe / ZnS quantum dots treated with 4 molar equivalents of ZnF2 (◆), and ZnSe / ZnS quantum dots treated with 14 molar equivalents of ZnF2 (■).

Figure 8

[0085] An X-ray photoelectron spectroscopy (XPS) investigation spectrum of ZnSe / ZnS quantum dots treated with ZnF2.

Figure 9A

[0086] A high-resolution XPS spectrum of the fluorine 1s region showing a comparison of standard ZnSe / ZnS quantum dots without using ZnF2 (Figure 9A) with ZnSe / ZnS quantum dots treated with ZnF2.

Figure 9B

Figure 10

[0087] Table comparing the solution quantum yield, maximum external quantum efficiency, and device lifetime of control ZnSe / ZnS quantum dots, ZnSe / ZnS quantum dots containing metal fluoride only in the shell layer, ZnSe / ZnS quantum dots containing metal fluoride only in the core layer, and ZnSe quantum dots containing metal fluoride in both the core and shell layers.

Figure 11

[0088] Bar graph showing the photoluminescence intensity of InP / ZnSe / ZnS quantum dots containing three different concentrations: 0 μL, 5 μL, and 20 μL of dodecylamine added to five different shell thicknesses of ZnSe and ZnS ((on an etched InP core) 4.5 monolayers of ZnSe and 2.5 monolayers of ZnS; 2.5 monolayers of ZnSe and 6.5 monolayers of ZnS; 2.5 monolayers of ZnSe and 2.5 monolayers of ZnS; 3.5 monolayers of ZnSe and 4.5 monolayers of ZnS; and 3.5 monolayers of ZnSe and 4.5 monolayers of ZnS).

Figure 12

[0089] Schematic showing L-facilitated Z-type ligand substitution where neutral Lewis base ligands (L) such as amines readily displace metal carboxylates (MX2 where M is Cd or Pb, X is O2CR, Cl, or SR, and R is C1-20 alkyl or oleyl) from carboxylate-terminated CdS, CdSe, PbS, or PbSe quantum dots. **Embodiments for Carrying Out the Invention**

[0079] **Definitions**

[0090] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The following definitions supplement the definitions in the art and are relevant to this application and, whether related or unrelated, for example, do not belong to any commonly owned patent or application. Any methods and materials similar or equivalent to those described herein can be used in the practice of the present invention, but the preferred materials and methods are described herein. Accordingly, the terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting.

[0080]

[0091] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise herein. Thus, for example, reference to "a nanostructure" includes a plurality of such nanostructures and the like.

[0081]

[0092] The term "about", as used herein, indicates that a given value of a quantity can vary by up to ±10% of that value. For example, "about 100 nm" encompasses sizes in the range from 90 nm to 110 nm, including that value.

[0082]

[0093] A "nanostructure" is a structure having at least one region or characteristic dimension with a dimension of less than about 500 nm. In some embodiments, the nanostructure has a dimension of less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm. Typically, the region or characteristic dimension is along the smallest axis of the structure. Examples of such structures include nanowires, nanorods, nanotubes, branched nanostructures, nanotetrapods, nanotripods, nanobipods, nanocrystals, nanodots, quantum dots, nanoparticles, and the like. The nanostructure can be, for example, substantially crystalline, substantially single crystal, polycrystalline, amorphous, or a combination thereof. In some embodiments, each of the three dimensions of the nanostructure has a dimension of less than about 500 nm, less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm.

[0083]

[0094] The term "heterostructure", when used with respect to a nanostructure, means a nanostructure characterized by at least two different and / or distinguishable material species. Typically, one region of the nanostructure comprises a first material species, while a second region of the nanostructure comprises a second material species. In certain embodiments, the nanostructure comprises a core of a first material and at least one shell of a second (or third, etc.) material, where the different material species are distributed, for example, radially with respect to the long axis of a nanowire, the long axis of an arm of a branched nanowire, or the center of a nanocrystal. The shell can completely cover the adjacent material considered as a shell or, in the case of a nanostructure, as a heterostructure, but it is not necessary to cover. For example, a nanocrystal characterized by a core of one material covered by islands of a second material is a heterostructure. In other embodiments, the different material species are distributed at different positions in the nanostructure, for example, along the major (long) axis of a nanowire or along the long axis of an arm of a branched nanowire. The different regions in the heterostructure can contain completely different materials or the various regions can contain a substrate (e.g., silicon) with different dopants or different concentrations of the same dopant.

[0084]

[0095] As used herein, the "diameter" of a nanostructure means the diameter of a cross-section perpendicular to the first axis of the nanostructure. The first axis has the greatest difference in length with respect to the second and third axes (the second and third axes are two axes having substantially equal lengths). The first axis is not necessarily the longest axis of the nanostructure. For example, with respect to a disk-shaped nanostructure, the cross-section is a substantially circular cross-section perpendicular to the short longitudinal axis of the disk. If the cross-sectional view is not circular, the diameter is the average of the major and minor axes of that cross-section. For an elongated or high aspect ratio nanostructure, such as a nanowire, the diameter is measured across a cross-section perpendicular to the longest axis of the nanowire. For a spherical nanostructure, the diameter is measured through the center of the sphere from one side to the other side.

[0085]

[0096] The terms "crystalline" or "substantially crystalline", when used with respect to nanostructures, mean that the nanostructure typically exhibits long-range order over one or more dimensions of the structure as a whole. It is understood by those skilled in the art that the term "long-range order" depends on the absolute size of a particular nanostructure, since the order for a single crystal cannot extend beyond the boundaries of the crystal. In this case, "long-range order" means substantial order over at least the majority of the dimensions of the nanostructure. In some examples, the nanostructure can have an oxide or other coating, or can be composed of a core and at least one shell. In such examples, the oxide, shell or other coating can exhibit such order (e.g., it can be amorphous, polycrystalline), but is not required to. In such cases, the phrases "crystalline", "substantially crystalline", "substantially single crystal", or "single crystal" mean the central core of the nanostructure (excluding the coating layer or shell). The terms "crystalline" or "substantially crystalline", as used herein, are also intended to include structures containing various defects, stacking defects, atomic substitutions, etc., as long as the structure exhibits substantial long-range order (e.g., order over at least about 80% more than the length of at least one axis of the nanostructure or its core). Additionally, it is clear that the interface between the core and the outside of the nanostructure, or between the core and an adjacent shell, or between a shell and a second adjacent shell, can contain an amorphous region or even be amorphous. As defined herein, this does not prevent the nanostructure from being crystalline or substantially crystalline.

[0086]

[0097] The term "single crystal", when used with respect to nanostructures, means that the nanostructure is substantially crystalline and contains substantially a single crystal. When used with respect to a nanostructure heterostructure containing a core and one or more shells, "single crystal" means that the core is substantially crystalline and contains substantially a single crystal.

[0087]

[0098] "Nanocrystal" is a nanostructure that is substantially a single crystal. Thus, a nanocrystal has at least one region or characteristic dimension with a dimension less than about 500 nm. In some embodiments, the nanocrystal has a dimension less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm. The term "nanocrystal" is intended to include substantially single crystal nanostructures including various defects, stacking defects, atomic substitutions, etc., as well as substantially single crystal nanostructures without such defects, stacking defects or substitutions. In the case of a nanocrystal heterostructure including a core and one or more shells, the core of the nanocrystal is typically substantially a single crystal, but the shell does not need to be substantially a single crystal. In some embodiments, each of the three dimensions of the nanocrystal has a dimension less than about 500 nm, less than about 200 nm, less than about 100 nm, less than about 50 nm, less than about 20 nm, or less than about 10 nm.

[0088]

[0099] The term "quantum dot" (or "dot") means a nanocrystal that exhibits quantum confinement or exciton confinement. Quantum dots can have material properties that are substantially homogeneous or, in certain embodiments, heterogeneous, and include, for example, a core and at least one shell. The optical properties of quantum dots can be affected by their particle size, chemical composition, and / or surface composition, and can be determined by appropriate optical tests available in the art. By being able to adjust the nanocrystal diameter, for example, in the range of about 1 nm to about 15 nm, the photoelectron emission range of all optical spectra can provide great flexibility in color rendering.

[0089]

[0100] A "ligand" is a molecule that can interact (strongly or weakly) with one or more surfaces of a nanostructure, for example, by covalent bonds, ions, van der Waals forces, or other molecular interactions with the surface of the nanostructure.

[0090]

[0101] "Photoluminescence quantum yield" is, for example, the ratio of photons emitted to photons absorbed by a nanostructure or a population of nanostructures. As is known in the art, the quantum yield is typically determined by a comparative study method using a standard sample that is well-characterized by known quantum yield values.

[0091]

[0102] As used herein, the term "monolayer" is a unit of measurement of the thickness of a shell derived from the volume crystal structure of the shell material as the closest distance between the relevant lattice planes. As an example, for a cubic lattice structure, the thickness of one monolayer is determined as the distance between adjacent lattice planes in the

[0111] direction. As an example, one monolayer of cubic ZnSe corresponds to 0.33 nm, and one monolayer of cubic ZnS corresponds to a thickness of 0.31 nm. The thickness of a monolayer of an alloy material can be determined from the alloy composition by Vegard's law.

[0092]

[0103] As used herein, the term "shell" refers to a material deposited onto a core or onto a previously deposited shell of the same or different composition, resulting from a single deposition of the shell material. The exact shell thickness depends on the material, as well as the precursor input and conversion, and can be reported in nanometers or monolayers. As used herein, "target shell thickness" refers to the intended shell thickness used for the calculation of the required precursor amount. As used herein, "actual shell thickness" refers to the actual deposited amount of the shell material after synthesis and can be measured by methods known in the art. As an example, the actual shell thickness can be measured by comparing the particle diameters determined from TEM images of the nanocrystals before and after shell synthesis.

[0093]

[0104] As used herein, the term "full width at half maximum" (FWHM) is a measure of the size distribution of quantum dots. The emission spectrum of a quantum dot generally has the shape of a Gaussian curve. The width of the Gaussian curve is defined as the FWHM and provides an indication of the size distribution of the particles. A smaller FWHM corresponds to a narrower quantum dot nanocrystal size distribution. The FWHM also depends on the maximum emission wavelength.

[0094]

[0105] The "peak emission wavelength" (PWL) is the wavelength at which the emission spectrum of a light source reaches its maximum.

[0095]

[0106] As used herein, the term "external quantum efficiency" (EQE) is the ratio of the number of photons emitted from a light-emitting diode (LED) to the number of electrons passing through the device. The EQE measures how efficiently the LED converts electrons into photons and emits them. The EQE can be measured using the following equation. EQE = [Injection efficiency] × [Solid-state quantum yield] × [Extraction efficiency] Wherein, Injection efficiency = the fraction of electrons passing through the device that are injected into the active region; Solid-state quantum yield = the fraction of all electron-hole recombinations in the active region that are radiative and thus produce photons; and Extraction efficiency = the fraction of photons generated in the active region that escape from the device.

[0096]

[0107] Unless expressly stated otherwise, the ranges recited herein are inclusive.

[0097]

[0108] Throughout this specification, various additional terms are defined or otherwise characterized.

[0098] Nanostructure

[0109] In some embodiments, the present disclosure provides a nanostructure comprising a core including a nanocrystal core; and at least one shell disposed on the core and including ZnS and a fluoride.

[0099]

[0110] In some embodiments, the core comprises ZnSe, ZnSeTe, InP, or InAs.

[0100]

[0111] In some embodiments, the core is ZnSe 1-x Te x (where 0 ≦ x < 1).

[0101]

[0112] In some embodiments, the nanostructure comprises two shells.

[0102]

[0113] In some embodiments, at least one shell comprises a first shell comprising ZnSe, and a second shell comprising ZnS and a fluoride. In some embodiments, at least one shell comprises a first shell comprising ZnSe and a fluoride, and a second shell comprising ZnS and a fluoride.

[0103]

[0114] In some embodiments, the fluoride is in the form of a metal fluoride, ammonium fluoride, or tetraalkylammonium fluoride.

[0104]

[0115] In some embodiments, the nanostructure is a quantum dot.

[0105]

[0116] In some embodiments, the fluoride is in the form of a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4. In some embodiments, the metal fluoride is ZnF2.

[0106]

[0117] In some embodiments, the present disclosure provides a nanostructure comprising a core comprising ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride; and at least one shell disposed on the core and comprising ZnS and optionally a second metal fluoride.

[0107]

[0118] In some embodiments, the nanostructure includes two shells.

[0108]

[0119] In some embodiments, the first metal fluoride is selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0109]

[0120] In some embodiments, the second metal fluoride is selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0110]

[0121] In some embodiments, the nanostructure is a quantum dot.

[0111]

[0122] In some embodiments, the nanostructure further includes at least one amine. In some embodiments, the at least one amine is bonded to the surface of the nanostructure.

[0112]

[0123] In some embodiments, the present disclosure provides a nanostructure including a core including a nanocrystal core; at least one shell disposed on the core and including ZnS and a fluoride; and at least one amine bonded to the surface of the nanostructure.

[0113]

[0124] In some embodiments, the present disclosure provides a nanostructure including a core including a nanocrystal core; at least one shell disposed on the core and including ZnS or ZnSe; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure.

[0114] Nanostructure film

[0125] In some embodiments, the present disclosure provides a nanostructure film including at least one population of nanostructures, wherein the nanostructures include a core including a nanocrystal core; and at least one shell disposed on the core, and wherein the at least one shell includes ZnS and a fluoride.

[0115]

[0126] In some embodiments, the present disclosure provides a nanostructured film comprising at least one population of nanostructures, each nanostructure comprising a core comprising a nanocrystal core; at least one shell disposed on the core and comprising ZnS or ZnSe; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure.

[0116]

[0127] In some embodiments, the present disclosure provides a nanostructured film comprising at least one population of nanostructures, wherein each nanostructure comprises a core comprising ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride; and at least one shell disposed on the core and comprising ZnS and optionally a second metal fluoride.

[0117]

[0128] In some embodiments, the present disclosure provides a nanostructured film comprising at least one population of nanostructures, each nanostructure comprising a core comprising InP; at least one shell disposed on the core and comprising ZnS or ZnSe; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure.

[0118]

[0129] In some embodiments, the nanostructured film further comprises at least one organic resin.

[0119]

[0130] In some embodiments, the nanostructures are quantum dots.

[0120] Nanostructured molded article

[0131] In some embodiments, the present disclosure provides a molded article comprising the nanostructured film described herein.

[0121]

[0132] In some embodiments, the molded article comprises (a) a first barrier layer; (b) a second barrier layer; and (c) A light-emitting layer between the first barrier layer and the second barrier layer, comprising a core containing a nanocrystal core; and at least one shell disposed on the core and containing ZnS and a fluoride, the light-emitting layer comprising a population of nanostructures comprising.

[0122]

[0133] In some embodiments, the molded article (a) A first barrier layer; (b) A second barrier layer; and (c) A light-emitting layer between the first barrier layer and the second barrier layer, comprising a core containing a nanocrystal core; at least one shell disposed on the core and containing ZnS or ZnSe; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure, the light-emitting layer comprising a population of nanostructures comprising.

[0123]

[0134] In some embodiments, the molded article (a) A first barrier layer; (b) A second barrier layer; and (c) A light-emitting layer between the first barrier layer and the second barrier layer, comprising a core containing ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride, and at least one shell disposed on the core and containing ZnS and optionally a second metal fluoride, the light-emitting layer comprising a population of nanostructures comprising.

[0124]

[0135] In some embodiments, the molded article (a) A first barrier layer; (b) A second barrier layer; and (c) A light-emitting layer between the first barrier layer and the second barrier layer, comprising a core containing InP; at least one shell disposed on the core and containing ZnS or ZnSe; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure, the light-emitting layer comprising a population of nanostructures comprising.

[0125]

[0136] In some embodiments, the nanostructures are quantum dots.

[0126]

[0137] In some embodiments, the molded article is an electroluminescent device. In some embodiments, the molded article is a light emitting diode. In some embodiments, the molded article is a liquid crystal display.

[0127] Fabrication of nanostructures

[0138] Various methods for the colloidal synthesis of nanostructures are known in the art, including, for example, techniques for controlling nanostructure growth to control the size and / or shape distribution of the resulting nanostructures.

[0128]

[0139] In a typical colloidal synthesis, semiconductor nanostructures are produced by rapidly injecting precursors that undergo thermal decomposition into a hot solution (e.g., a hot solvent and / or surfactant). The precursors can be injected simultaneously or sequentially. The precursors react rapidly to form nuclei. Nanostructure growth occurs by monomer addition to the nuclei.

[0129]

[0140] The surfactant molecules interact with the surface of the nanostructures. At growth temperatures, the surfactant molecules rapidly adsorb and desorb from the nanostructure surface, allowing for the addition and / or removal of atoms from the nanostructure while suppressing agglomeration of the growing nanostructures. Generally, weakly coordinating surfactant bonds to the nanostructure surface allow for rapid nanostructure growth, while surfactants that bind more strongly to the nanostructure surface result in slower nanostructure growth. The surfactant can also interact with one (or more) precursors to slow nanostructure growth.

[0130]

[0141] Typically, spherical nanostructures are obtained by nanostructure growth in the presence of a single surfactant. By using a mixture of two or more surfactants, the growth can be controlled. For example, when two (or more) surfactants adsorb differently on different crystal surfaces of the growing nanostructure, non-spherical nanostructures can be produced.

[0131]

[0142] Thus, a number of parameters are known to affect nanostructure growth and are operable, either independently or in combination, to control the size and / or shape distribution of the resulting nanostructures. These include, for example, temperature (nucleation and / or growth), precursor composition, time-dependent precursor concentration, ratio of precursors to each other, surfactant composition, number of surfactants, and ratio of surfactants to each other and / or to the precursor.

[0132]

[0143] The synthesis of group II-VI nanostructures is described, for example, in U.S. Pat. Nos. 6,225,198, 6,322,901, 6,207,229, 6,607,829, 7,060,243, 7,374,824, 6,861,155, 7,125,605, 7,566,476, 8,158,193, and 8,101,234, and U.S. Patent Application Publication Nos. 2011 / 0262752 and 2011 / 0263062, each of which is hereby incorporated by reference in its entirety.

[0133]

[0144] Group II-VI nanostructures, such as CdSe / CdS / ZnS core / shell nanostructures, can exhibit desirable luminescence behavior as described above, but due to issues such as the toxicity of cadmium, the applications in which such nanostructures can be used are limited. Thus, a less toxic alternative with good luminescence properties is highly desirable.

[0134]

[0145] In some embodiments, the nanostructure is cadmium-free. As used herein, the term "cadmium-free" is intended to mean that the nanostructure contains less than 100 ppm cadmium by weight. By definition of compliance with the Restriction of Hazardous Substances (RoHS), there should be no more than 0.01% by weight (100 ppm) cadmium in the raw homogeneous precursor material. The cadmium level in the Cd-free nanostructures of the present invention is limited by the trace metal concentration in the precursor material. The trace metal concentration (including cadmium) in the precursor material for the Cd-free nanostructures is evaluated by inductively coupled plasma mass spectrometry (ICP-MS) analysis and is at the parts per billion (ppb) level. In some embodiments, the "cadmium-free" nanostructure contains less than about 50 ppm, less than about 20 ppm, less than about 10 ppm or less than about 1 ppm cadmium.

[0135]

[0146] In some embodiments, the nanostructure includes a nanocrystal core. In some embodiments, the core includes ZnSe, ZnSeTe, InP, or InAs. In some embodiments, the core is ZnSe 1-x Te x (where 0 ≦ x < 1). In some embodiments, the core includes ZnSe. In some embodiments, the core includes InP.

[0136]

[0147] In some embodiments, the nanostructure includes at least one shell disposed on the core. In some embodiments, the at least one shell includes ZnSe. In some embodiments, the at least one shell includes ZnS. In some embodiments, the at least one shell includes ZnSe and the at least one shell includes ZnS.

[0137]

[0148] In some embodiments, at least one shell comprises ZnS and a fluoride. In some embodiments, the nanostructure comprises two shells. In some embodiments, at least one shell comprises ZnSe. In some embodiments, at least one shell comprises ZnSe and a fluoride. In some embodiments, at least one shell comprises a first shell comprising ZnSe and a second shell comprising ZnS and a fluoride. In some embodiments, at least one shell comprises a first shell comprising ZnSe and a fluoride and a second shell comprising ZnS and a fluoride. In some embodiments, the fluoride is in the form of a metal fluoride, ammonium fluoride, or a tetraalkylammonium fluoride. In some embodiments, the fluoride is in the form of a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4. In some embodiments, the metal fluoride is ZnF2.

[0138]

[0149] In some embodiments, the nanostructure comprises a core comprising InP and at least one shell comprising ZnS or ZnSe, hi some embodiments, the nanostructure comprises a core comprising InP, at least one shell comprising ZnS, and at least one shell comprising ZnSe.

[0139]

[0150] In some embodiments, the nanostructures comprise a core comprising ZnSe and at least one shell comprising ZnS and ZnF2. In some embodiments, the nanostructures comprise a core comprising ZnSe, at least one shell comprising ZnSe, and at least one shell comprising ZnS and ZnF2. In some embodiments, the nanostructures comprise a core comprising ZnSe, at least one shell comprising ZnSe and ZnF2, and at least one shell comprising ZnS and ZnF2. In some embodiments, the nanostructures comprise a core comprising ZnSe, at least one shell comprising ZnSe and ZnF2, and at least one shell comprising ZnS and ZnF2. 1-x Te x where 0≦x<1, and at least one shell comprising ZnS and ZnF. In some embodiments, the nanostructure comprises ZnSe1-x Te x where 0≦x<1, at least one shell comprising ZnSe, and at least one shell comprising ZnS and ZnF. In some embodiments, the nanostructure comprises a core comprising ZnSe 1-x Te x wherein 0≦x<1, at least one shell comprising ZnSe and ZnF 2 , and at least one shell comprising ZnS and ZnF 2 .

[0140]

[0151] In some embodiments, the nanostructures are ZnSe or ZnSe 1-x Te x wherein 0≦x<1 and a first metal fluoride. In some embodiments, the core comprises ZnSe 1-x Te x where 0≦x<1 and a first metal fluoride. In some embodiments, the core comprises ZnSe and a first metal fluoride. In some embodiments, the first metal fluoride is selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0141]

[0152] In some embodiments, the nanostructure comprises at least one shell disposed on a core. In some embodiments, the at least one shell comprises ZnS and optionally a second metal fluoride. In some embodiments, the nanostructure comprises two shells. In some embodiments, the at least one shell comprises ZnSe. In some embodiments, the at least one shell comprises a first shell comprising ZnSe and a second shell comprising ZnS and optionally a second metal fluoride. In some embodiments, the second metal fluoride is selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0142]

[0153] In some embodiments, the nanostructures comprise a core comprising ZnSe and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; and at least one shell comprising ZnS and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0143]

[0154] In some embodiments, the nanostructures comprise a core comprising ZnSe and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; at least one shell comprising ZnSe and at least one shell comprising ZnS and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0144]

[0155] In some embodiments, the nanostructures comprise a core comprising ZnSe and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; and at least one shell comprising ZnS.

[0145]

[0156] In some embodiments, the nanostructures comprise a core comprising ZnSe and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; at least one shell comprising ZnSe; and at least one shell comprising ZnS.

[0146]

[0157] In some embodiments, the nanostructures are ZnSe 1-x Te x (In the formula, 0 <x<1である)並びにZnF2、HfF4及びZrF4からなる群から選択される金属フッ化物を含むコアと;ZnS並びにZnF2、HfF4及びZrF4からなる群から選択される金属フッ化物を含む少なくとも1つのシェルとを含む。

[0147]

[0158] In some embodiments, the nanostructures are ZnSe 1-x Te x(where 0 < x < 1) and a core containing a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; at least one shell containing ZnSe; and at least one shell containing ZnS and a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4.

[0148]

[0159] In some embodiments, the nanostructure is ZnSe 1-x Te x (where 0 < x < 1) and a core containing a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; and at least one shell containing ZnS.

[0149]

[0160] In some embodiments, the nanostructure is ZnSe 1-x Te x (where 0 < x < 1) and a core containing a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4; at least one shell containing ZnSe; and at least one shell containing ZnS.

[0150]

[0161] In some embodiments, the nanostructure is prepared using the method of U.S. Patent Application Publication No. 2017 / 0306227, which is hereby incorporated by reference in its entirety.

[0151]

[0162] In some embodiments, the nanostructure is a quantum dot.

[0152]

[0163] In some embodiments, the nanostructure is substantially cubic.

[0153] Solvent

[0164] In some embodiments, the nanostructure further comprises a solvent.

[0154]

[0165] In some embodiments, the solvent is selected from the group consisting of chloroform, acetone, hexane, heptane, octane, butanone, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, 1,4-butanediol diacetate, diethylene glycol monobutyl ether acetate, ethylene glycol monobutyl ether acetate, glyceryl triacetate, heptyl acetate, hexyl acetate, pentyl acetate, butyl acetate, ethyl acetate, diethylene glycol butyl methyl ether, diethylene glycol monobutyl ether, di(propylene glycol) dimethyl ether, diethylene glycol ethyl methyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, methyl ethyl ketone, methyl isobutyl ketone, monomethyl ether glycol ester, gamma-butyrolactone, 3-ethyl methyl acetate, butyl carbitol, butyl carbitol acetate, propanediol monomethyl ether, propanediol monomethyl ether acetate, cyclohexane, toluene, xylene, isopropyl alcohol, and combinations thereof.

[0155]

[0166] In some embodiments, the solvent is a nonpolar solvent. In some embodiments, the nonpolar solvent is selected from the group consisting of hexane, heptane, octane, toluene, and mixtures thereof. In some embodiments, the nonpolar solvent is octane. In some embodiments, the nonpolar solvent is hexane.

[0156] Manufacture of nanostructures with fluoride passivation in the shell

[0167] In some embodiments, the present disclosure provides a nanostructure by: (a) providing a nanocrystal core; (b) optionally, mixing the core of (a) with a zinc source and a selenium source to provide a core having a ZnSe shell; (c) mixing the core of (a) or the core having a ZnSe shell of (b) with a fluoride source; and Leaching a solution containing a zinc source and a sulfur source in a mixture of (d) and (c). Provided is a method for preparing a nanostructure, which includes the above steps.

[0157]

[0168] In some embodiments, the core includes ZnSe, ZnSeTe, InP, or InAs. In some embodiments, the core includes ZnSe 1-x Te x (where 0 ≦ x < 1). In some embodiments, the core includes ZnSe.

[0158]

[0169] In some embodiments, the molar ratio of the fluoride source to the nanocrystal core is from about 1:1 to about 30:1, about 1:1 to about 25:1, about 1:1 to about 20:1, about 1:1 to about 15:1, about 1:1 to about 10:1, about 1:1 to about 9:1, about 1:1 to about 8:1, about 1:1 to about 7:1, 1:1 to about 6:1, about 1:1 to about 5:1, about 1:1 to about 4:1, about 1:1 to about 3:1, or about 1:1 to about 2:1. In some embodiments, the molar ratio of the fluoride source to the nanocrystal core is about 1:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, about 10:1, about 11:1, about 12:1, about 13:1, about 14:1, about 15:1, about 16:1, about 17:1, about 18:1, about 19:1, about 20:1, about 21:1, about 22:1, about 23:1, about 24:1, about 25:1, about 26:1, about 27:1, about 28:1, about 29:1, or about 30:1.

[0159]

[0170] In some embodiments, the zinc source of (b) is a dialkyl zinc compound. In some embodiments, the zinc source of (b) is a zinc carboxylate. In some embodiments, the zinc source of (b) is diethyl zinc, dimethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate or a mixture thereof. In some embodiments, the zinc source of (b) is zinc oleate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate or a mixture thereof. In some embodiments, the zinc source of (b) is zinc oleate.

[0160]

[0171] In some embodiments, the selenium source of (b) is an alkyl-substituted selenourea. In some embodiments, the selenium source of (b) is a phosphine selenide. In some embodiments, the selenium source of (b) is trioctylphosphine selenide, tris(n-butyl)phosphine selenide, tris(sec-butyl)phosphine selenide, tris(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, tricyclohexylphosphine selenide, cyclohexylphosphine selenide, 1-octaselenol, 1-dodecaselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl) selenide, selenourea or a mixture thereof. In some embodiments, the selenium source of (b) is tris(n-butyl)phosphine selenide, tris(sec-butyl)phosphine selenide or tris(tert-butyl)phosphine selenide. In some embodiments, the selenium source of (b) is trioctylphosphine selenide.

[0161]

[0172] In some embodiments, the mixing in (b) is at a temperature of about 250°C to about 350°C. In some embodiments, the mixing in (b) is at a temperature of about 310°C.

[0162]

[0173] In some embodiments, the mixing in (b) comprises mixing the core of (a) with a zinc source, a selenium source, and optionally a fluoride source to provide a core having a shell containing ZnSe and fluoride.

[0163]

[0174] In some embodiments, the fluoride source is a metal fluoride, ammonium fluoride, or tetraalkylammonium fluoride.

[0164]

[0175] In some embodiments, the fluoride source is a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4. In some embodiments, the metal fluoride is ZnF2. In some embodiments, the metal fluoride is HfF4. In some embodiments, the metal fluoride is ZrF4.

[0165]

[0176] In some embodiments, the fluoride source is a tetraalkylammonium fluoride selected from the group consisting of tetrabutylammonium fluoride, tetrapropylammonium fluoride, diisopropyldimethylammonium fluoride, tetraethylammonium fluoride, and tetramethylammonium fluoride, dioctadecyldimethylammonium fluoride, dihexadecyldimethylammonium fluoride, ditetradecyldimethylammonium fluoride, didodecyldimethylammonium fluoride, didecyldimethylammonium fluoride, dioctyldimethylammonium fluoride, bis(ethylhexyl)dimethylammonium fluoride, octadecyltrimethylammonium fluoride, oleyltrimethylammonium fluoride, hexadecyltrimethylammonium fluoride, tetradecyltrimethylammonium fluoride, dodecyltrimethylammonium fluoride, decyltrimethylammonium fluoride, octyltrimethylammonium fluoride, phenylethyltrimethylammonium fluoride, benzyltrimethylammonium fluoride, phenyltrimethylammonium fluoride, benzylhexadecyldimethylammonium fluoride, benzyltetradecyldimethylammonium fluoride, benzyldodecyldimethylammonium fluoride, benzyldecyldimethylammonium fluoride, benzyloctyldimethylammonium fluoride, benzyltributylammonium fluoride, and benzyltriethylammonium fluoride.

[0166]

[0177] In some embodiments, the tetraalkylammonium fluoride is tetrabutylammonium fluoride.

[0167]

[0178] In some embodiments, the mixing in (c) is at a temperature of about 20°C to about 120°C. In some embodiments, the mixing in (c) is at a temperature of about 100°C.

[0168]

[0179] In some embodiments, the mixing in (c) further comprises an amine source.

[0169]

[0180] In some embodiments, the amine source is a lower alkyl amine, alkenyl amine, hydroalkyl amine, haloalkyl amine, primary aryl amine, secondary aryl amine, or heterocyclic amine. In some embodiments, the amine source is a secondary amine, i.e., an amine having an amine group containing two C-N bonds and one N-H bond. In some embodiments, the amine source contains a total of 20 or fewer carbon atoms. In some embodiments, the amine source contains 10 or fewer carbon atoms. Examples of primary amines are alkyl amines such as ethyl amine, butyl amine, hexyl amine, octyl amine, decyl amine, hexadecyl amine, and octadecyl amine; alkenyl amines such as allyl amine, 2-hexenyl amine, 4-decenyl amine, and octadecenyl amine; alkanol amines such as ethanol amine, octanol amine, and dodecanol amine; haloalkyl amines such as beta-chloroethyl amine; and aryl amines such as aniline. Examples of secondary amines that can be used to prepare the compounds described herein are dialkyl amines such as diethyl amine, di-n-propyl amine, diisobutyl amine, dihexyl amine, and dioctyl amine; dialkenyl amines such as diallyl amine and dihexenyl amine; dialkanol amines such as diethanol amine and didodecanol amine; dihaloalkyl amines such as bis(beta-chloroethyl) amine; and N,N'-dialkyl alkylene diamines such as N,N-dimethyl ethylene diamine. The secondary amine does not necessarily have to contain two identical substituents. Examples of such mixed amines include N-methyl ethanol amine, N-methyl allyl amine, and N-methyl aniline. Additional secondary amines include amines in which the amine nitrogen is contained within a heterocyclic ring. In some embodiments, the heterocyclic amine is a six-membered heterocyclic amine. Examples of such heterocyclic amines include morpholine, piperidine, pyrrolidine, N-methyl piperazine, hexamethylene imine, and thiomorpholine. In some embodiments, the heterocyclic amine may contain additional heteroatoms such as nitrogen, oxygen, or sulfur.

[0170]

[0181] In some embodiments, the zinc source in (d) is a dialkyl zinc compound. In some embodiments, the zinc source in (d) is a zinc carboxylate. In some embodiments, the zinc source in (d) is diethyl zinc, dimethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source in (d) is zinc oleate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source in (d) is zinc oleate.

[0171]

[0182] In some embodiments, the sulfur source in (d) is selected from the group consisting of trioctylphosphine sulfide, elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide, and combinations thereof. In some embodiments, the sulfur source in (d) is trioctylphosphine sulfide.

[0172]

[0183] In some embodiments, leaching in (d) is at a temperature of about 280°C to about 320°C. In some embodiments, leaching in (d) is at a temperature of about 310°C.

[0173]

[0184] In some embodiments, the infusion in (d) is at a rate of about 0.05 mL / min to about 5.0 mL / min. In some embodiments, the infusion in (d) is at a rate of about 0.1 mL / min.

[0174]

[0185] In some embodiments, the molar ratio of fluoride bound to the nanostructure to zinc in the nanostructure is from about 0.05 to about 0.35. In some embodiments, the molar ratio of fluoride bound to the nanostructure to zinc in the nanostructure is about 0.13.

[0175]

[0186] In some embodiments, the nanostructure is cooled to room temperature. In some embodiments, an organic solvent is added to dilute the reaction mixture comprising the nanostructure.

[0176]

[0187] In some embodiments, the organic solvent used to dilute the reaction mixture is ethanol, hexane, pentane, toluene, benzene, diethyl ether, acetone, ethyl acetate, dichloromethane (methylene chloride), chloroform, dimethylformamide or N-methylpyrrolidinone. In some embodiments, the organic solvent is toluene. In some embodiments, the organic solvent is a combination of toluene and ethanol.

[0177]

[0188] In some embodiments, the nanostructure is isolated. In some embodiments, the nanostructure is isolated by precipitation using an organic solvent. In some embodiments, the nanostructure is isolated by aggregation with ethanol. In some embodiments, the nanostructure is further isolated by centrifugation followed by decantation of the organic solvent.

[0178] Production of Nanostructures with Fluoride Passivation in the Core

[0189] In some embodiments, the present disclosure provides a nanostructure by (a) mixing a solution of a zinc source, a selenium source, and a first metal fluoride source to provide a core comprising ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride; (b) optionally combining the core of (a) with a zinc source and a selenium source to provide a core having a ZnSe shell; (c) optionally, mixing the core of (a) or the core having a ZnSe shell of (b) with a second metal fluoride source; and (d) leaching a solution containing a zinc source and a sulfur source in a mixture of (a), (b), or (c); The present invention provides a method for preparing nanostructures, comprising:

[0179]

[0190] In some embodiments, the molar ratio of the first metal fluoride source to the core is about 1:1 to 10:1, about 1:1 to about 9:1, about 1:1 to about 8:1, about 1:1 to about 7:1, about 1:1 to about 6:1, about 1:1 to about 5:1, about 1:1 to about 4:1, about 1:1 to about 3:1, or about 1:1 to about 2:1. In some embodiments, the molar ratio of the first metal fluoride source to the core is about 1:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, or about 10:1.

[0180]

[0191] In some embodiments, the molar ratio of the second metal fluoride source to the core is from about 1:1 to about 30:1, from about 1:1 to about 25:1, from about 1:1 to about 20:1, from about 1:1 to about 15:1, from about 1:1 to about 10:1, from about 1:1 to about 9:1, from about 1:1 to about 8:1, from about 1:1 to about 7:1, from 1:1 to about 6:1, from about 1:1 to about 5:1, from about 1:1 to about 4:1, from about 1:1 to about 3:1, or from about 1:1 to about 2:1. In some embodiments, the molar ratio of the second metal fluoride source to the nanocrystal core is about 1:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, about 10:1, about 11:1, about 12:1, about 13:1, about 14:1, about 15:1, about 16:1, about 17:1, about 18:1, about 19:1, about 20:1, about 21:1, about 22:1, about 23:1, about 24:1, about 25:1, about 26:1, about 27:1, about 28:1, about 29:1, or about 30:1.

[0181]

[0192] In some embodiments, the selenium source of (a) is selected from the group consisting of trioctylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, cyclohexylphosphine selenide, octaselenol, dodecaselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl) selenide, and mixtures thereof. In some embodiments, the selenium source of (a) is trioctylphosphine selenide.

[0182]

[0193] In some embodiments, the zinc source of (a) is a dialkylzinc compound. In some embodiments, the zinc source of (a) is a zinc carboxylate. In some embodiments, the zinc source of (a) is diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof. In some embodiments, the zinc source of (a) is zinc oleate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof. In some embodiments, the zinc source of (a) is zinc oleate.

[0183]

[0194] In some embodiments, the first metal fluoride of (a) is selected from the group consisting of ZnF2, HfF4, and ZrF4. In some embodiments, the first metal fluoride source of (a) is ZnF2. In some embodiments, the first metal fluoride source of (a) is HfF4. In some embodiments, the first metal fluoride source of (a) is ZrF4.

[0184]

[0195] In some embodiments, the mixing in (a) further comprises a first amine source.

[0185]

[0196] In some embodiments, the amine source is a lower alkylamine, alkenylamine, hydroalkylamine, haloalkylamine, primary arylamine, secondary arylamine, or heterocyclic amine. In some embodiments, the amine source is a secondary amine, i.e., an amine having an amine group containing two C-N bonds and one N-H bond. In some embodiments, the amine source contains a total of 20 or fewer carbon atoms. In some embodiments, the amine source contains 10 or fewer carbon atoms. Examples of primary amines are alkylamines such as ethylamine, butylamine, hexylamine, octylamine, decylamine, hexadecylamine, and octadecylamine; alkenylamines such as allylamine, 2-hexenylamine, 4-decenylamine, and octadecenylamine; alkanolamines such as ethanolamine, octanolamine, and dodecanolamine; haloalkylamines such as beta-chloroethylamine; and arylamines such as aniline. Examples of secondary amines that can be used to prepare the compounds described herein are dialkylamines such as diethylamine, di-n-propylamine, diisobutylamine, dihexylamine, and dioctylamine; dialkenylamines such as diallylamine and dihexenylamine; dialkanolamines such as diethanolamine and didodecanolamine; dihaloalkylamines such as bis(beta-chloroethyl)amine; and N,N'-dialkylalkylenediamines such as N,N-dimethylethylenediamine. The secondary amine does not necessarily have to contain two identical substituents. Examples of such mixed amines include N-methylethanolamine, N-methylallylamine, and N-methylaniline. Additional secondary amines include amines in which the amine nitrogen is contained within a heterocycle. In some embodiments, the heterocyclic amine is a six-membered heterocyclic amine. Examples of such heterocyclic amines include morpholine, piperidine, pyrrolidine, N-methylpiperazine, hexamethyleneimine, and thiomorpholine. In some embodiments, the heterocyclic amine may contain additional heteroatoms such as nitrogen, oxygen, or sulfur.

[0186]

[0197] In some embodiments, the mixing in (a) is at a temperature of about 70 °C to about 130 °C. In some embodiments, the mixing in (a) is at a temperature of about 100 °C.

[0187]

[0198] In some embodiments, the zinc source in (b) is a dialkylzinc compound. In some embodiments, the zinc source in (b) is a zinc carboxylate. In some embodiments, the zinc source in (b) is diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate or a mixture thereof. In some embodiments, the zinc source in (b) is zinc oleate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate or a mixture thereof. In some embodiments, the zinc source in (b) is zinc oleate.

[0188]

[0199] In some embodiments, the selenium source in (b) is selected from the group consisting of trioctylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, cyclohexylphosphine selenide, octaselenol, dodecaselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl) selenide and mixtures thereof. In some embodiments, the selenium source in (b) is trioctylphosphine selenide.

[0189]

[0200] In some embodiments, the mixing in (b) is at a temperature of about 250°C to about 350°C. In some embodiments, the mixing in (b) is at a temperature of about 310°C.

[0190]

[0201] In some embodiments, the second metal fluoride in (c) is selected from the group consisting of ZnF2, HfF4, and ZrF4. In some embodiments, the second metal fluoride source in (c) is ZnF2. In some embodiments, the second metal fluoride source in (c) is HfF4. In some embodiments, the second metal fluoride source in (c) is ZrF4.

[0191]

[0202] In some embodiments, the mixing in (c) further comprises a second amine source.

[0192]

[0203] In some embodiments, the amine source is a lower alkylamine, alkenylamine, hydroalkylamine, haloalkylamine, primary arylamine, secondary arylamine, or heterocyclic amine. In some embodiments, the amine source is a secondary amine, i.e., an amine having an amine group containing two C-N bonds and one N-H bond. In some embodiments, the amine source contains a total of 20 or fewer carbon atoms. In some embodiments, the amine source contains 10 or fewer carbon atoms. Examples of primary amines are alkylamines such as ethylamine, butylamine, hexylamine, octylamine, decylamine, hexadecylamine, and octadecylamine; alkenylamines such as allylamine, 2-hexenylamine, 4-decenylamine, and octadecenylamine; alkanolamines such as ethanolamine, octanolamine, and dodecanolamine; haloalkylamines such as beta-chloroethylamine; and arylamines such as aniline. Examples of secondary amines that can be used to prepare the compounds described herein are dialkylamines such as diethylamine, di-n-propylamine, diisobutylamine, dihexylamine, and dioctylamine; dialkenylamines such as diallylamine and dihexenylamine; dialkanolamines such as diethanolamine and didodecanolamine; dihaloalkylamines such as bis(beta-chloroethyl)amine; and N,N'-dialkylalkylenediamines such as N,N-dimethylethylenediamine. The secondary amine does not necessarily have to contain two identical substituents. Examples of such mixed amines include N-methylethanolamine, N-methylallylamine, and N-methylaniline. Additional secondary amines include amines in which the amine nitrogen is contained within a heterocyclic ring. In some embodiments, the heterocyclic amine is a six-membered heterocyclic amine. Examples of such heterocyclic amines include morpholine, piperidine, pyrrolidine, N-methylpiperazine, hexamethyleneimine, and thiomorpholine. In some embodiments, the heterocyclic amine may contain additional heteroatoms such as nitrogen, oxygen, or sulfur.

[0193]

[0204] In some embodiments, the mixing in (c) is at a temperature of about 70°C to about 130°C. In some embodiments, the mixing in (c) is at a temperature of about 100°C.

[0194]

[0205] In some embodiments, the zinc source in (d) is a dialkyl zinc compound. In some embodiments, the zinc source in (d) is a zinc carboxylate. In some embodiments, the zinc source in (d) is diethyl zinc, dimethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source in (d) is zinc oleate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or a mixture thereof. In some embodiments, the zinc source in (d) is zinc oleate.

[0195]

[0206] In some embodiments, the sulfur source in (d) is selected from the group consisting of trioctylphosphine sulfide, elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, α-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide, and combinations thereof. In some embodiments, the sulfur source in (d) is trioctylphosphine sulfide.

[0196]

[0207] In some embodiments, leaching in (d) is at a temperature of about 250°C to about 350°C. In some embodiments, leaching in (d) is at a temperature of about 310°C.

[0197]

[0208] In some embodiments, the infusion at (d) is at a rate of about 0.05 mL / min to about 5.0 mL / min. In some embodiments, the infusion at (d) is at a rate of about 0.5 mL / min.

[0198]

[0209] In some embodiments, the molar ratio of nanostructure-bound fluoride to zinc in the nanostructure is from about 0.05 to about 0.35.

[0199]

[0210] In some embodiments, the nanostructures are cooled to room temperature, hi some embodiments, an organic solvent is added to dilute the reaction mixture containing the nanostructures.

[0200]

[0211] In some embodiments, the organic solvent used to dilute the reaction mixture is ethanol, hexane, pentane, toluene, benzene, diethyl ether, acetone, ethyl acetate, dichloromethane (methylene chloride), chloroform, dimethylformamide, or N-methylpyrrolidinone. In some embodiments, the organic solvent is toluene. In some embodiments, the organic solvent is a combination of toluene and ethanol.

[0201]

[0212] In some embodiments, the nanostructures are isolated. In some embodiments, the nanostructures are isolated by precipitation using an organic solvent. In some embodiments, the nanostructures are isolated by coagulation with ethanol. In some embodiments, the nanostructures are further isolated by centrifugation followed by decantation of the organic solvent.

[0202] Amine Passivation

[0213] In some embodiments, the present disclosure provides a nanostructure comprising: a core comprising a nanocrystal core; at least one shell disposed on the core comprising ZnS and a fluoride; and at least one amine bound to the nanostructure. In some embodiments, the present disclosure provides a nanostructure comprising: a core comprising a nanocrystal core; at least one shell disposed on the core comprising ZnS; at least one fluoride bound to the nanostructure; and at least one amine bound to the nanostructure.

[0203]

[0214] Most quantum dots' native ligand combinations (e.g., carboxylates and phosphines) are not soluble in a wide range of organic media and are incompatible with matrix materials commonly used in the preparation of quantum dot films. Ligand exchange can be used to resolve these issues, but exchange can affect surface trap states and, therefore, the photoluminescence quantum yield of the quantum dots. Furthermore, it has been found that photoluminescence quantum yield and linkage are not simply related, not only because of their nonlinear independent nature, but also because metal carboxylate complexes can be simultaneously substituted with amine bonds.

[0204]

[0215] Furthermore, quantum dots, particularly InP quantum dots, are known to be sensitive to primary amines, which limits the choice of matrix materials and / or ligands that can be used with InP quantum dots.

[0205]

[0216] Attempts to reduce the relative extent of quenching of InP quantum dots have shown only moderate success. For example, it has been found possible to reduce the extent of quantum yield quenching by amines by using thick inorganic shell coatings of InP quantum dots. As shown in Figure 11, the thickest shell coatings, containing 2.5 monolayers of ZnSe and 6.5 monolayers of ZnS, prevented a greater amount of quantum dot quenching by dodecylamine than the thinnest shell coatings, containing 2.5 monolayers of ZnSe and 2.5 monolayers of ZnS. However, quantum dots with very thick shells may develop strain-induced interface traps that can ultimately result in lower absolute quantum yields.

[0206]

[0217] An investigation into the coordination chemistry of carboxylate-terminated CdSe, CdS, PbSe, and PbS quantum dots provides an explanation for the loss mechanism (Anderson, NC, et al., J. Am. Chem. Soc. 135: 18536-18548 (2013)). As shown in Figure 12, neutral Lewis base ligands (L), such as amines, readily displace metal carboxylates (MX2, where M is Cd or Pb and X is OC1R, Cl, or SR) from carboxylate-terminated CdSe, CdS, PbS, or PbS quantum dots. The amine molecules coordinate to the metal carboxylates and to the metal sites on the quantum dot surface. Therefore, the resulting amine-metal complexes are highly soluble and easily removed from the quantum dot surface.

[0207]

[0218] Amines can bind to the surface of metal sites. Model studies have shown that amines can convert CdTe into Cd-Cd dimers on negatively charged CdTe quantum dots. 2+Prevention of reduction has been shown (du Fosse, I., et al., Chem. Mater. 31:4575-4583 (2019)). For example, the binding of amines to the surface of quantum dots containing fluoride ligands is thought to be promoted by the low steric requirements of fluoride ligands such as zinc fluoride compared to native ligands such as zinc oleate. Thus, fluoride ligands and amines can coexist on the quantum dot surface and can inactivate both holes and electron traps.

[0208]

[0219] In some embodiments, the amine attached to the nanostructure surface is a lower alkylamine, alkenylamine, hydroalkylamine, haloalkylamine, primary arylamine, secondary arylamine, or heterocyclic amine. In some embodiments, the amine attached to the nanostructure surface is a secondary amine, i.e., an amine having an amine group containing two C-N bonds and one N-H bond. In some embodiments, the amine attached to the nanostructure surface contains a total of 20 or fewer carbon atoms. In some embodiments, the amine attached to the nanostructure surface contains 10 or fewer carbon atoms. Examples of primary amines are alkylamines such as ethylamine, butylamine, hexylamine, octylamine, decylamine, hexadecylamine, and octadecylamine; alkenylamines such as allylamine, 2-hexenylamine, 4-decenylamine, and octadecenylamine; alkanolamines such as ethanolamine, octanolamine, and dodecanolamine; haloalkylamines such as betachloroethylamine; and arylamines such as aniline. Examples of secondary amines capable of binding to the surface of the nanostructures described herein include dialkylamines, such as diethylamine, di-n-propylamine, diisobutylamine, dihexylamine, and dioctylamine; dialkenylamines, such as diallylamine and dihexenylamine; dialkanolamines, such as diethanolamine and didecanolamine; dihaloalkylamines, such as bis(beta-chloroethyl)amine; and N,N'-dialkylalkylenediamines, such as N,N-dimethylethylenediamine. Secondary amines do not necessarily contain two identical substituents. Examples of such mixed amines include N-methylethanolamine, N-methylallylamine, and N-methylaniline. Additional secondary amines include amines in which the amine nitrogen is contained within a heterocyclic ring. In some embodiments, the heterocyclic amine is a six-membered heterocyclic amine. Examples of such heterocyclic amines include morpholine, piperidine, pyrrolidine, N-methylpiperazine, hexamethyleneimine, and thiomorpholine.In some embodiments, the heterocyclic amine may contain additional heteroatoms, such as nitrogen, oxygen or sulfur.

[0209] First ligand

[0220] In some embodiments, the nanostructures include ligands attached to their surfaces. In some embodiments, the nanostructures include a coating layer that includes ligands that protect the nanostructures from external moisture and oxidation, control flocculation, and enable dispersion of the nanostructures in the matrix material. Suitable first ligands include U.S. Patent Nos. 6,949,206; 7,267,875; 7,374,807; 7,572,393; 7,645,397; and 8,563,133, which are hereby incorporated by reference in their entirety; and U.S. Patent Application Publication Nos. 2008 / 0237540; 2008 / 0281010; and 2010 / 0110728.

[0210]

[0221] In some embodiments, the nanostructures include a multi-part ligand structure, such as the three-part ligand structure disclosed in U.S. Patent Application Publication No. 2008 / 237540, in which a head group, a tail group, and a middle / body group are independently manufactured, optimized for their specific functions, and then combined into a fully surface ligand that functions ideally.

[0211]

[0222] In some embodiments, the first ligand includes one or more organic polymer ligands. Suitable ligands provide efficient and strong binding quantum dot encapsulation in a low oxygen permeability state; precipitate or separate in regions of the matrix material to form a discontinuous two-phase or multiphase matrix; disperse favorably in the matrix material; and are either commercially available materials or can be easily formulated from commercially available materials.

[0212]

[0223] In some embodiments, the first ligand includes carboxy, thiol, phosphine or phosphine oxide groups.

[0213]

[0224] In some embodiments, the first ligand comprises a carboxy group. In some embodiments, the first ligand comprises a carboxylic acid group. In some embodiments, the first ligand comprises a carboxylic acid group, and the carboxylic acid is caprylic acid, capric acid, lauric acid, myristic acid, or palmitic acid. In some embodiments, the first ligand is a carboxylate. In some embodiments, the first ligand comprises a carboxylate, and the carboxylate is a carboxyalkyl.

[0214]

[0225] In some embodiments, the first ligand comprises a metal carboxylate. In some embodiments, the first ligand is a metal carboxylate selected from the group consisting of zinc oleate, zinc hexanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, and zinc PEG-carboxylate. In some embodiments, the first ligand is a metal carboxylate selected from the group consisting of zinc oleate, zinc laurate, and zinc PEG-carboxylate. In some embodiments, the first ligand is zinc oleate.

[0215]

[0226] In some embodiments, the first ligand comprises a phosphine group, hi some embodiments, the first ligand comprises a phosphine group, and the phosphine group is triphenylphosphine, tributylphosphine, trihexylphosphine, trioctylphosphine (TOP), or tridecylphosphine.

[0216]

[0227] In some embodiments, the first ligand comprises a phosphine oxide group, hi some embodiments, the first ligand comprises a phosphine oxide group, and the phosphine oxide is triphenylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide (TOPO), or tridecylphosphine oxide.

[0217] Ligand Exchange

[0228] In some embodiments, the present invention relates to a method of exchanging ligands on a nanostructure. In some embodiments, a first ligand on the nanostructure is exchanged with at least one fluoride ligand. During ligand exchange, at least one functional group of the fluoride ligand replaces the native hydrophobic ligand of the nanostructure to provide stable anchoring of the ligand on the nanocrystal surface. In some embodiments, the nanostructure is a quantum dot.

[0218]

[0229] In some embodiments, the first ligand is covalently bound to the nanostructure. In some embodiments, the first ligand is non-covalently bound to the nanostructure.

[0219]

[0230] In some embodiments, the present disclosure relates to a method of replacing a first ligand on a nanostructure with a second ligand, comprising mixing a population of nanostructures having a first ligand bound to the nanostructure with at least one fluoride ligand that is the second ligand such that the second ligand replaces the first ligand and binds to the nanostructure.

[0220]

[0231] In some embodiments, the fluoride ligand is selected from metal fluorides, ammonium fluoride, or tetraalkylammonium fluoride.

[0221]

[0232] In some embodiments, the fluoride ligand is a metal fluoride selected from the group consisting of ZnF2, HfF4, and ZrF4. In some embodiments, the metal fluoride is ZnF2. In some embodiments, the metal fluoride is HfF4. In some embodiments, the metal fluoride is ZrF4.

[0222]

[0233] In some embodiments, the fluoride ligand is selected from the group consisting of tetrabutylammonium fluoride, tetrapropylammonium fluoride, diisopropyldimethylammonium fluoride, tetraethylammonium fluoride, and tetramethylammonium fluoride, dioctadecyldimethylammonium fluoride, dihexadecyldimethylammonium fluoride, ditetradecyldimethylammonium fluoride, didodecyldimethylammonium fluoride, didecyldimethylammonium fluoride, dioctyldimethylammonium fluoride, bis(ethylhexyl)dimethylammonium fluoride, octadecyltrimethylammonium fluoride, oleyltrimethylammonium fluoride, hexadecyltrimethylammonium fluoride, and tetramethylammonium fluoride. The tetraalkylammonium fluoride is selected from the group consisting of tetradecyltrimethylammonium, dodecyltrimethylammonium fluoride, decyltrimethylammonium fluoride, octyltrimethylammonium fluoride, phenylethyltrimethylammonium fluoride, benzyltrimethylammonium fluoride, phenyltrimethylammonium fluoride, benzylhexadecyldimethylammonium fluoride, benzyltetradecyldimethylammonium fluoride, benzyldodecyldimethylammonium fluoride, benzyldecyldimethylammonium fluoride, benzyloctyldimethylammonium fluoride, benzyltributylammonium fluoride, and benzyltriethylammonium fluoride.

[0223]

[0234] In some embodiments, the tetraalkylammonium fluoride is tetrabutylammonium fluoride.

[0224]

[0235] In some embodiments, the fluoride ligand is tetrabutylammonium fluoride.

[0225]

[0236] In some embodiments, the nanostructures are quantum dots.

[0226]

[0237] In some embodiments, the second ligand covalently binds to the nanostructure. In some embodiments, the second ligand non-covalently binds to the nanostructure.

[0227]

[0238] In some embodiments, the mixing is carried out at a temperature of about 0 °C to about 200 °C, about 0 °C to about 150 °C, about 0 °C to about 100 °C, about 0 °C to about 80 °C, about 20 °C to about 200 °C, about 20 °C to about 150 °C, about 20 °C to about 100 °C, about 20 °C to about 80 °C, about 50 °C to about 200 °C, about 50 °C to about 150 °C, about 50 °C to about 100 °C, about 50 °C to about 80 °C, about 80 °C to about 200 °C, about 80 °C to about 150 °C, about 80 °C to about 100 °C, about 100 °C to about 200 °C, about 100 °C to about 150 °C or about 150 °C to about 200 °C. In some embodiments, the mixing is carried out at a temperature of about 50 °C to about 100 °C. In some embodiments, the mixing is carried out at a temperature of about 70 °C.

[0228]

[0239] In some embodiments, the mixing is carried out for a period of about 1 minute and about 6 hours, about 1 minute and about 2 hours, about 1 minute and about 1 hour, about 1 minute and about 40 minutes, about 1 minute and about 30 minutes, about 1 minute and about 20 minutes, about 1 minute and about 10 minutes, about 10 minutes and about 6 hours, about 10 minutes and about 2 hours, about 10 minutes and about 1 hour, about 10 minutes and about 40 minutes, about 10 minutes and about 30 minutes, about 10 minutes and about 20 minutes, about 20 minutes and about 6 hours, about 20 minutes and about 2 hours, about 20 minutes and about 1 hour, about 20 minutes and about 40 minutes, about 20 minutes and about 30 minutes, about 30 minutes and about 6 hours, about 30 minutes and about 2 hours, about 30 minutes and about 1 hour, about 30 minutes and about 40 minutes, about 40 minutes and about 6 hours, about 40 minutes and about 2 hours, about 40 minutes and about 1 hour, about 1 hour and about 6 hours, about 1 hour and about 2 hours or about 2 hours and about 6 hours. In some embodiments, the mixing is carried out for a period of about 40 minutes and about 2 hours. In some embodiments, the mixing is carried out for a period of about 1 hour.

[0229]

[0240] In some embodiments, the reaction mixture further comprises a solvent. In some embodiments, the solvent is selected from the group consisting of chloroform, acetone, butanone, tetrahydrofuran, 2-methyltetrahydrofuran, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol diethyl ether, methyl isobutyl ketone, monomethyl ether glycol ester, gamma-butyrolactone, 3-ethyl ether methyl acetate, butyl carbitol, butyl carbitol acetate, propanediol monomethyl ether, propanediol monomethyl ether acetate, cyclohexane, toluene, xylene, isopropyl alcohol, and combinations thereof. In some embodiments, the solvent is toluene.

[0230]

[0241] The percentage of the first ligand substituted by the fluoride ligand is 19 measurable by 19F NMR or Fourier transform infrared spectroscopy (FTIR). In some embodiments, the molar percentage of the first ligand substituted by the fluoride ligand is about 20% to about 100%, about 20% to about 80%, about 20% to about 60%, about 20% to about 40%, about 25% to about 100%, about 25% to about 80%, about 25% to about 60%, about 25% to about 40%, about 30% to about 100%, about 30% to about 80%, about 30% to about 60%, about 30% to about 40%, about 40% to about 100%, about 40% to about 80%, about 40% to about 60%, about 60% to about 100%, about 60% to about 80%, or about 80% to about 100%.

[0231]

[0242] The percentage of the fluoride ligand bound to the nanostructures of the population of nanostructures is 19 measurable by 19F NMR, and the bound ligand is calculated using (bound fluoride ligand) / (bound + free fluoride ligand).

[0232]

[0243] In some embodiments, the molar percentage of fluoride ligands attached to the nanostructure is between about 20% and about 100%, between about 20% and about 100%, between about 20% and about 80%, between about 20% and about 60%, between about 20% and about 40%, between about 25% and about 100%, between about 25% and about 80%, between about 25% and about 60%, between about 25% and about 40%, between about 30% and about 100%, between about 30% and about 80%, between about 30% and about 60%, between about 30% and about 40%, between about 40% and about 100%, between about 40% and about 80%, between about 40% and about 60%, between about 60% and about 100%, between about 60% and about 80%, or between about 80% and about 100%.

[0233] Fabrication of nanostructures with fluoride ligands and amines

[0244] In some embodiments, the present disclosure provides a method for providing a nanostructure by: (a) a nanostructure comprising a nanocrystal core and at least one shell comprising ZnS or ZnSe disposed on the core; and (b) at least one fluoride source; and (c) at least one amine source The present invention provides a method for preparing nanostructures, comprising mixing:

[0234]

[0245] In some embodiments, the molar ratio of fluoride source to nanostructures is about 0.5:1 to about 10:1, about 0.5:1 to about 9:1, about 0.5:1 to about 8:1, about 0.5:1 to about 7:1, about 0.5:1 to about 6:1, about 0.5:1 to about 5:1, about 0.5:1 to about 4:1, about 0.5:1 to about 3:1, about 0.5:1 to about 2:1, or about 0.5:1 to about 1:1. In some embodiments, the molar ratio of fluoride source to nanostructures is about 0.5:1, about 1:1, about 2:1, about 3:1, about 4:1, about 5:1, about 6:1, about 7:1, about 8:1, about 9:1, or about 10:1.

[0235]

[0246] In some embodiments, the nanostructure of (a) is InP / ZnSe / ZnS. In some embodiments, the nanostructure of (a) is red-emitting InP / ZnSe / ZnS. In some embodiments, the nanostructure of (a) is green-emitting InP / ZnSe / ZnS.

[0236]

[0247] In some embodiments, the fluoride source of (b) is selected from the group consisting of tetraalkylammonium fluoride, ZnF2, HfF4, and ZrF4. In some embodiments, the fluoride source of (b) is ZnF2. In some embodiments, the fluoride source of (b) is HfF4. In some embodiments, the fluoride source of (b) is ZrF4. In some embodiments, the fluoride source of (b) is tetraalkylammonium fluoride.

[0237]

[0248] In some embodiments, the amine source of (c) is a lower alkylamine, alkenylamine, hydroalkylamine, haloalkylamine, primary arylamine, secondary arylamine, or heterocyclic amine. In some embodiments, the amine source of (c) is a secondary amine, i.e., an amine having an amine group containing two C-N bonds and one N-H bond. In some embodiments, the amine source of (c) contains a total of 20 or fewer carbon atoms. In some embodiments, the amine source of (c) contains 10 or fewer carbon atoms. Examples of primary amines are alkylamines such as ethylamine, butylamine, hexylamine, octylamine, decylamine, hexadecylamine, and octadecylamine; alkenylamines such as allylamine, 2-hexenylamine, 4-decenylamine, and octadecenylamine; alkanolamines such as ethanolamine, octanolamine, and dodecanolamine; haloalkylamines such as beta-chloroethylamine; and arylamines such as aniline. Examples of secondary amines that can be used to prepare the compounds described herein are dialkylamines such as diethylamine, di-n-propylamine, diisobutylamine, dihexylamine, and dioctylamine; dialkenylamines such as diallylamine and dihexenylamine; dialkanolamines such as diethanolamine and didodecanolamine; dihaloalkylamines such as bis(beta-chloroethyl)amine; and N,N'-dialkylalkylenediamines such as N,N-dimethylethylenediamine. The secondary amine does not necessarily have to contain two identical substituents. Examples of such mixed amines include N-methylethanolamine, N-methylallylamine, and N-methylaniline. Additional secondary amines include amines in which the amine nitrogen is contained within a heterocycle. In some embodiments, the heterocyclic amine is a six-membered heterocyclic amine. Examples of such heterocyclic amines include morpholine, piperidine, pyrrolidine, N-methylpiperazine, hexamethyleneimine, and thiomorpholine.In some embodiments, the heterocyclic amine may contain additional heteroatoms, such as nitrogen, oxygen or sulfur. In some embodiments, the amine source is octylamine.

[0238]

[0249] In some embodiments, the mixing is at a temperature of about 50°C to about 130°C. In some embodiments, the mixing is at a temperature of about 50°C to about 130°C, about 50°C to about 100°C, about 50°C to about 70°C, about 70°C to about 130°C, about 70°C to about 100°C or about 100°C to about 130°C. In some embodiments, the mixing is at a temperature of 70°C.

[0239]

[0250] In some embodiments, the molar ratio of the bonded fluoride to the nanostructure is about 0.05 to about 0.35.

[0240]

[0251] In some embodiments, the nanostructure is cooled to room temperature. In some embodiments, an organic solvent is added to dilute the reaction mixture containing the nanostructure.

[0241]

[0252] In some embodiments, the organic solvent used to dilute the reaction mixture is ethanol, hexane, pentane, toluene, benzene, diethyl ether, acetone, ethyl acetate, dichloromethane (methylene chloride), chloroform, dimethylformamide or N-methylpyrrolidinone. In some embodiments, the organic solvent is toluene. In some embodiments, the organic solvent is a combination of toluene and ethanol.

[0242]

[0253] In some embodiments, the nanostructure is isolated. In some embodiments, the nanostructure is isolated by precipitation using an organic solvent. In some embodiments, the nanostructure is isolated by aggregation with ethanol. In some embodiments, the nanostructure is further isolated by centrifugation followed by decantation of the organic solvent.

[0243] Improved properties of nanostructures

[0254] In some embodiments, core / shell nanostructures prepared using the methods described herein exhibit high photoluminescence quantum yields. In some embodiments, core / shell nanostructures can have photoluminescence quantum yields of 60% to 100%, 60% to 95%, 60% to 90%, 60% to 85%, 60% to 80%, 60% to 70%, 70% to 100%, 70% to 95%, 70% to 90%, 70% to 85%, 70% to 80%, 80% to 100%, 80% to 95%, 80% to 90%, 80% to 85%, 85% to 100%, 85% to 95%, 80% to 85%, 85% to 100%, 85% to 90%, 90% to 100%, 90% to 95%, or 95% to 100%. In some embodiments, core / shell nanostructures prepared using the methods described herein have a photoluminescence quantum yield of 60% to 99%. In some embodiments, core / shell nanostructures prepared using the methods described herein have a photoluminescence quantum yield of 70% to 99%.

[0244]

[0255] The photoluminescence spectrum of core / shell nanostructures prepared using the methods described herein can encompass essentially any desired portion of the spectrum. In some embodiments, the photoluminescence spectrum of the core / shell nanostructure has a peak emission wavelength (PWL) of 300 nm to 750 nm, 300 nm to 650 nm, 300 nm to 550 nm, 300 nm to 450 nm, 450 nm to 750 nm, 450 nm to 650 nm, 450 nm to 550 nm, 450 nm to 750 nm, 450 nm to 650 nm, 450 nm to 550 nm, 550 nm to 750 nm, 550 nm to 650 nm, or 650 nm to 750 nm. In some embodiments, the photoluminescence spectrum of the core / shell nanostructure has a PWL of 400 nm to 500 nm.

[0245]

[0256] The size distribution of core / shell nanostructures prepared using the methods described herein can be relatively narrow. In some embodiments, the photoluminescence spectrum of a population or core / shell nanostructures prepared using the methods described herein has a full width at half maximum of 10 nm to 60 nm, 10 nm to 40 nm, 10 nm to 30 nm, 10 nm to 20 nm, 20 nm to 60 nm, 20 nm to 40 nm, 20 nm to 30 nm, 30 nm to 60 nm, 30 nm to 40 nm, or 40 nm to 60 nm. In some embodiments, the photoluminescence spectrum of a population or core / shell nanostructures prepared using the methods described herein has a full width at half maximum of 10 nm to 40 nm. In some embodiments, the photoluminescence spectrum of a population of core / shell nanostructures prepared using the methods described herein has a full width at half maximum of 30 nm to 45 nm.

[0246] Nanostructured Membranes

[0257] In some embodiments, the core / shell nanostructures prepared by the methods described herein are incorporated into nanostructured films, hi some embodiments, the nanostructured films are incorporated into quantum dot-enhanced films (QDEFs).

[0247]

[0258] In some embodiments, the present disclosure provides: (a) at least one population of nanostructures comprising: a core comprising a nanocrystal core; and at least one shell disposed on the core, the shell comprising ZnS and fluoride; and (b) at least one organic resin The present invention provides a nanostructured film comprising:

[0248]

[0259] In some embodiments, the present disclosure provides: (a) at least one population of nanostructures comprising: a core comprising a nanocrystal core; at least one shell disposed on the core, the shell comprising ZnS; at least one fluoride bonded to a surface of the nanostructure; and at least one amine bonded to a surface of the nanostructure; and (b) at least one organic resin To provide a nanostructured film containing the same.

[0249]

[0260] In some embodiments, the nanostructure is a quantum dot.

[0250]

[0261] In some embodiments, the present disclosure (a) A core containing ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride; and at least one shell containing ZnS and optionally a second metal fluoride disposed on the core; and (b) At least one organic resin To provide a nanostructured film containing the same.

[0251]

[0262] In some embodiments, the present disclosure (a) A core containing InP; at least one shell containing ZnS or ZnSe disposed on the core; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure; and (b) At least one organic resin To provide a nanostructured film containing the same.

[0252]

[0263] In some embodiments, the nanostructure is a quantum dot.

[0253]

[0264] In some embodiments, the core / shell nanostructure is embedded in a matrix. As used herein, the term "embedded" is used to indicate that the nanostructure is contained within or encapsulated by a matrix material that constitutes the major component of the matrix. In some embodiments, the nanostructures are uniformly distributed throughout the matrix material. In some embodiments, the nanostructures are distributed according to an application-specific uniform distribution function.

[0254]

[0265] In some embodiments, the nanostructures can include a homogeneous population having sizes that emit in the blue visible wavelength spectrum, the green visible wavelength spectrum, or the red visible wavelength spectrum. In some embodiments, the nanostructures can include a first population of nanostructures having sizes that emit in the blue visible wavelength spectrum, a second population of nanostructures having sizes that emit in the green visible wavelength spectrum, and a third population of nanostructures having sizes that emit in the red visible wavelength spectrum.

[0255]

[0266] The matrix material can be any suitable host matrix material capable of accommodating the nanostructure. The suitable matrix material can be chemically and optically compatible with the nanostructure and any surrounding packaging material or layer used when applying the nanostructure film to a device. The suitable matrix material can include a non-yellowing optical material that is transparent to both primary and secondary light, and thus both primary and secondary light can be transmitted through the matrix material. The matrix material can include polymers and organic and inorganic oxides. Suitable polymers used in the matrix material can be any polymers known to those skilled in the art that can be used for such purposes. The polymer can be substantially translucent or substantially transparent. Matrix materials include, but are not limited to, epoxies, acrylates, norbornenes, polyethylenes, poly(vinyl butyral):poly(vinyl acetate), polyureas, polyurethanes; silicones and silicone derivatives including, but not limited to, aminosilicone (AMS), polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, silsesquioxane, fluorinated silicone, and vinyl and hydride substituted silicone; acrylic polymers and copolymers formed from monomers including, but not limited to, methyl methacrylate, butyl methacrylate, and lauryl methacrylate; styrene-based polymers such as polystyrene, aminopolystyrene (APS), and poly(acrylonitrile ethylene styrene) (AES); polymers crosslinked by difunctional monomers such as divinylbenzene; epoxides that form epoxies in combination with suitable crosslinking agents, ligand amines (such as APS or polyethyleneimine ligand amines) for crosslinking ligand materials, etc.

[0256]

[0267] In some embodiments, the matrix material includes dispersed microbeads such as TiO2 microbeads, ZnS microbeads, or glass microbeads that can improve the light conversion efficiency of the nanostructured film. In some embodiments, the matrix material can include a light-shielding element.

[0257]

[0268] In some embodiments, the matrix material can have low oxygen and moisture permeability, can exhibit high light and chemical stability, can exhibit a good refractive index, and can adhere to the outer surface of the nanostructure, thus providing an airtight seal that protects the nanostructure. In another embodiment, the matrix material can be curable by UV or thermal curing methods to facilitate roll-to-roll processing.

[0258]

[0269] In some embodiments, the nanostructured film can be formed by mixing the nanostructures in a polymer (e.g., photoresist) and casting the nanostructure-polymer mixture onto a substrate, mixing the nanostructures with monomers and polymerizing them together, mixing the nanostructures in a sol-gel to form an oxide, or by any other method known to those skilled in the art.

[0259]

[0270] In some embodiments, the formation of the nanostructured film can include a film extrusion process. The film extrusion process can include forming a homogeneous mixture of a matrix material and a core-shell nanostructure coated with a barrier layer, such as a nanostructure functionalized with a metal halide and / or a metal carboxylate, and introducing the homogeneous mixture into an upper attachment hopper that feeds an extruder. In some embodiments, the homogeneous mixture can be in the form of pellets. The film extrusion process can further include extruding the nanostructured film from a slot die and passing the extruded nanostructured film over a cooling roll. In some embodiments, the extruded nanostructured film can have a thickness in the range of less than about 75 μm, such as about 70 μm to about 40 μm, about 65 μm to about 40 μm, about 60 μm to about 40 μm, or about 50 μm to about 40 μm. In some embodiments, the nanostructured film has a thickness of less than about 10 μm. In some embodiments, the formation of the nanostructured film can optionally include a secondary process, after which the film extrusion process can be performed. The secondary process can include a process that provides a texture to the upper surface of the nanostructured film layer, such as coextrusion forming, thermoforming, vacuum forming, plasma treatment, molding, and / or embossing. The textured upper surface nanostructured film can, for example, assist in improving the defined optical diffusion properties and / or the defined angular optical emission properties of the nanostructured film.

[0260] Nanostructured article

[0271] In some embodiments, the nanostructured composition is used to form a nanostructured article. In some embodiments, the nanostructured article is a liquid crystal display (LCD) or a light emitting diode (LED). In some embodiments, the nanostructured composition is used to form a light emitting layer of a lighting device. The lighting device can be used in a wide variety of applications such as flexible electronic devices, touch screens, monitors, televisions, mobile phones, and any other high-resolution display. In some embodiments, the lighting device is a light emitting diode or a liquid crystal display. In some embodiments, the lighting device is a quantum dot light emitting diode (QLED). Examples of QLEDs are disclosed in U.S. Patent Application Publication No. 15 / 824,701, which is incorporated herein by reference in its entirety.

[0261]

[0272] In some embodiments, the present disclosure provides (a) a first conductive layer; (b) a second conductive layer; and (c) a light emitting layer between a first barrier layer and a second barrier layer, the light emitting layer comprising a population of nanostructures comprising a core comprising a nanocrystal core; and at least one shell disposed on the core and comprising ZnS and a fluoride and providing a light emitting diode.

[0262]

[0273] In some embodiments, the present disclosure provides (a) a first conductive layer; (b) a second conductive layer; and (c) a light emitting layer between a first barrier layer and a second barrier layer, the light emitting layer comprising a population of nanostructures comprising a core comprising a nanocrystal core; at least one shell disposed on the core and comprising ZnS or ZnSe; at least one fluoride bonded to the surface of the nanostructure; and at least one amine bonded to the surface of the nanostructure and providing a light emitting diode.

[0263]

[0274] In some embodiments, the present disclosure is (a) a first barrier layer; (b) a second barrier layer; and (c) a light-emitting layer between the first barrier layer and the second barrier layer, the light-emitting layer comprising a core comprising ZnSe or ZnSe 1-x Te x (where 0 ≦ x < 1) and a first metal fluoride; and at least one shell comprising ZnS and optionally a second metal fluoride disposed on the core; a population of nanostructures A light-emitting diode comprising is provided.

[0264]

[0275] In some embodiments, the present disclosure is (a) a first barrier layer; (b) a second barrier layer; and (c) a light-emitting layer between the first barrier layer and the second barrier layer, the light-emitting layer comprising a core comprising InP; at least one shell comprising ZnS or ZnSe disposed on the core; at least one fluoride bonded to the surface of the nanostructure; and a population of nanostructures comprising at least one amine bonded to the surface of the nanostructure A light-emitting diode comprising is provided.

[0265]

[0276] In some embodiments, the light-emitting layer is a nanostructured film.

[0266]

[0277] In some embodiments, the light-emitting diode comprises a first conductive layer, a second conductive layer, and a light-emitting layer disposed between the first conductive layer and the second conductive layer. In some embodiments, the light-emitting layer is a thin film.

[0267]

[0278] In some embodiments, the light-emitting diode includes additional layers between the first conductive layer and the second conductive layer, such as a hole injection layer, a hole transport layer, and an electron transport layer. In some embodiments, the hole injection layer, the hole transport layer, and the electron transport layer are thin films. In some embodiments, the layers are laminated on a substrate.

[0268]

[0279] When a voltage is applied to the first conductive layer and the second conductive layer, holes injected into the first conductive layer move to the light-emitting layer through the hole injection layer and / or the hole transport layer, and electrons injected from the second conductive layer move to the light-emitting layer through the electron transport layer. The holes and electrons recombine in the light-emitting layer to generate excitons.

[0269] Quantum dots of a glass LCD display device

[0280] In some embodiments, the nanostructured film is incorporated into quantum dots on a glass LCD display device. The LCD display device can include a nanostructured film formed directly on a light guide plate (LGP) without the need for an intermediate substrate or barrier layer. In some embodiments, the nanostructured film can be a thin film. In some embodiments, the nanostructured film can have a thickness of 500 μm or less, or 100 μm or less, or 50 μm or less. In some embodiments, the nanostructured film is a thin film having a thickness of about 15 μm or less.

[0270]

[0281] The LGP can include an optical cavity having one or more sides, including at least an upper side, including glass. The glass provides excellent resistance to impurities including moisture and air. Further, the glass can be formed as a thin substrate while maintaining structural rigidity. Thus, the LGP can be formed at least partially from the glass surface to provide a substrate having sufficient barrier and structural properties.

[0271]

[0282] In some embodiments, a nanostructured film can be formed on an LGP. In some embodiments, the nanostructured film comprises a population of nanostructures embedded in a matrix material, such as a resin. The nanostructured film can be formed on an LGP by any method known in the art, such as wet coating, painting, spin coating, or screen printing. After deposition, the nanostructured film resin can be cured. In some embodiments, one or more nanostructured film resins can be partially cured, further processed, and finally cured. The nanostructured film can be deposited as a single layer or as separate layers, and the separate layers can include various properties. The width and height of the nanostructured film can be any desired dimension depending on the size of the viewing panel of the display device. For example, the nanostructured film can have a relatively small surface area for small display device embodiments such as watches and phones, or the nanostructured film can have a large surface area for large display device embodiments such as televisions and computer monitors.

[0272]

[0283] In some embodiments, an optically transparent substrate is formed on the nanostructured film by any method known in the art, such as vacuum deposition, vapor deposition, etc. The optically transparent substrate can be configured to provide environmental sealing to layers and / or structures underlying the nanostructured film. In some embodiments, a light-blocking element can be included in the optically transparent substrate. In some embodiments, the light-blocking element can be included in a second polar filter, which can be disposed between the substrate and the nanostructured film. In some embodiments, the light-blocking element can be a dichroic filter that can, for example, reflect a first light (e.g., blue light, UV light, or a combination of UV light and blue light) while transmitting a second light. The light-blocking element can include specific UV light filtering components to filter out any unconverted UV light from the red and green subpixels and / or UV light from the blue subpixels.

[0273] On-chip and near-chip placement of quantum dots

[0284] In some embodiments, the nanostructures are incorporated into the display device by "on-chip" placement. As used herein, "on-chip" refers to placing the nanostructures in the LED cup. In some embodiments, the nanostructures are dissolved in a resin or fluid to fill the LED cup.

[0274]

[0285] In some embodiments, the nanostructures are incorporated into the display device in a "near-chip" configuration, which as used herein means that the top surface of the LED assembly is coated with nanostructures so that the exiting light passes through the nanostructure film.

[0275] Display device with nanostructured color conversion layer

[0286] In some embodiments, the present invention provides (a) a first light-emitting display panel; (b) a backlight unit configured to provide a first light to the display panel; and (c) a color filter including at least one pixel region including a color conversion layer; A display device comprising:

[0276]

[0287] In some embodiments, the color filter includes at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 pixel regions. In some embodiments, when blue light is incident on the color filter, red light, white light, green light, and / or blue light can be emitted through the pixel regions, respectively. In some embodiments, the color filter is described in U.S. Patent Application Publication No. 2017 / 153366, which is incorporated herein by reference in its entirety.

[0277]

[0288] In some embodiments, each pixel region includes a color conversion layer. In some embodiments, the color conversion layer includes the nanostructures described herein configured to convert incident light rays into light of a first color. In some embodiments, the color conversion layer includes the nanostructures described herein configured to convert incident light rays into blue light.

[0278]

[0289] In some embodiments, the display device includes 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 color conversion layers. In some embodiments, the display device includes one color conversion layer including the nanostructures described herein. In some embodiments, the display device includes two color conversion layers including the nanostructures described herein. In some embodiments, the display device includes three color conversion layers including the nanostructures described herein. In some embodiments, the display device includes four color conversion layers including the nanostructures described herein. In some embodiments, the display device includes at least one red conversion layer, at least one green conversion layer, and at least one blue conversion layer.

[0279]

[0290] In some embodiments, the color conversion layer has a thickness of about 3 μm to about 10 μm, about 3 μm to about 8 μm, about 3 μm to about 6 μm, about 6 μm to about 10 μm, about 6 μm to about 8 μm, or about 8 μm to about 10 μm. In some embodiments, the color conversion layer has a thickness of about 3 μm to about 10 μm.

[0280]

[0291] Although not limited thereto, the nanostructured color conversion layer can be deposited by any suitable method known in the art, including painting, spray coating, solvent spraying, wet coating, adhesive coating, spin coating, tape - coating, roll coating, flow coating, inkjet printing, photoresist patterning, drop casting, blade coating, mist deposition, or combinations thereof. In some embodiments, the nanostructured color conversion layer is deposited by photoresist patterning. In some embodiments, the nanostructured color conversion layer is deposited by inkjet printing.

[0281] Inkjet printing

[0292] The formation of thin films using the dispersion of nanostructures in an organic solvent is often achieved by coating techniques such as spin coating. However, these coating techniques are generally not suitable for the formation of thin films over large areas and do not provide a means for patterning the deposited layer, and thus their use is limited. Inkjet printing enables the accurate patterning of large - scale thin films at low cost. Inkjet printing also enables the accurate patterning of nanostructured layers, enables printed pixels for displays, and eliminates optical patterning. Thus, inkjet printing is very attractive for industrial applications, particularly in display applications.

[0282]

[0293] Commonly used solvents for inkjet printing are dipropylene glycol monomethyl ether acetate (DPMA), polyglycidyl methacrylate (PGMA), diethylene glycol monoethyl ether acetate (EDGAC), and propylene glycol methyl ether acetate (PGMEA). Volatile solvents are often used in inkjet printing because they allow for rapid drying. Volatile solvents include ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and tetrahydrofuran. Conventional nanostructures generally cannot dissolve in these solvents. However, due to the increased hydrophilicity of nanostructures containing poly(alkylene oxide) ligands, their solubility in these solvents increases.

[0283]

[0294] In some embodiments, the nanostructures described herein used for inkjet printing are dispersed in a solvent selected from DPMA, PGMA, EDGAC, PGMEA, ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, tetrahydrofuran, chloroform, chlorobenzene, cyclohexane, hexane, heptane, octane, hexadecane, undecane, decane, dodecane, xylene, toluene, benzene, octadecane, tetradecane, butyl ether, or a combination thereof. In some embodiments, the nanostructures described herein including poly(alkylene oxide) ligands used for inkjet printing are dispersed in a solvent selected from DPMA, PGMA, EDGAC, PGMEA, ethanol, methanol, 1-propanol, 2-propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, tetrahydrofuran, or a combination thereof.

[0284]

[0295] For application by inkjet printing or microdispersion, the inkjet composition containing nanostructures must be dissolved in a suitable solvent. The solvent must be able to disperse the nanostructure composition and must not have any harmful effects on the selected printhead.

[0285]

[0296] In some embodiments, the inkjet composition further comprises one or more additional components such as a surface active compound, a lubricant, a wetting agent, a dispersion aid, a hydrophobizing agent, an adhesive, a fluidity improver, an antifoaming agent, a degassing agent, a diluent, an auxiliary agent, a colorant, a dye, a pigment, a photosensitizer, a stabilizer, and an inhibitor.

[0286]

[0297] In some embodiments, the nanostructure composition described herein constitutes from about 0.01% to about 20% of the inkjet composition by weight. In some embodiments, the nanostructures containing poly(alkylene oxide) ligands constitute from about 0.01% to about 20%, from about 0.01% to about 15%, from about 0.01% to about 10%, from about 0.01% to about 5%, from about 0.01% to about 2%, from about 0.01% to about 1%, from about 0.01% to about 0.1%, from about 0.01% to about 0.05%, from about 0.05% to about 20%, from about 0.05% to about 15%, from about 0.05% to about 10%, from about 0.05% to about 5%, from about 0.05% to about 2%, from about 0.05% to about 1%, from about 0.05% to about 0.1%, from about 0.1% to about 20%, from about 0.1% to about 15%, from about 0.1% to about 10%, from about 0.1% to about 5%, from about 0.1% to about 2%, from about 0.1% to about 1%, from about 0.5% to about 20%, from about 0.5% to about 15%, from about 0.5% to about 10%, from about 0.5% to about 5%, from about 0.5% to about 2%, from about 0.5% to about 1%, from about 1% to about 20%, from about 1% to about 15%, from about 1% to about 10%, from about 1% to about 5%, from about 1% to about 2%, from about 2% to about 20%, from about 2% to about 15%, from about 2% to about 10%, from about 2% to about 5%, from about 5% to about 20%, from about 5% to about 15%, from about 5% to about 10%, from about 10% to about 20%, from about 10% to about 15%, or from about 15% to 20% of the inkjet composition by weight.

[0287]

[0298] In some embodiments, an inkjet composition comprising a nanostructure or nanostructure composition described herein is used in a formulation of an electronic device. In some embodiments, an inkjet composition comprising a nanostructure or nanostructure composition described herein is used in a formulation of an electronic device selected from the group consisting of nanostructured films, display devices, lighting devices, backlight units, color filters, surface emitting devices, electrodes, magnetic memory devices, and batteries. In some embodiments, an inkjet composition comprising a nanostructure composition described herein is used in a formulation of a light emitting device.

[0288] Lighting device with improved characteristics

[0299] In some embodiments, a lighting device prepared using the nanostructures of the present disclosure exhibits an EQE of about 1.5% to about 20%, about 1.5% to about 15%, about 1.5% to about 12%, about 1.5% to about 10%, about 1.5% to about 8%, about 1.5% to about 4%, about 1.5% to about 3%, about 3% to about 20%, about 3% to about 15%, about 3% to about 12%, about 3% to about 10%, about 3% to about 8%, about 8% to about 20%, about 8% to about 15%, about 8% to about 12%, about 8% to about 10%, about 10% to about 20%, about 10% to about 15%, about 10% to about 12%, about 12% to about 20%, about 12% to about 15% or about 15% to about 20%. In some embodiments, a lighting device prepared using the nanostructures of the present disclosure exhibits an EQE of about 1.5% to about 15%. In some embodiments, a lighting device prepared using the nanostructures of the present disclosure exhibits an EQE of about 5%. In some embodiments, the lighting device is a light emitting diode.

[0289]

[0300] In some embodiments, lighting devices prepared using the nanostructures of the present disclosure exhibit improved lifetimes. In some embodiments, lighting devices prepared using the nanostructures of the present disclosure exhibit an optical density of 500 cd / m 2 or higher after about 1 second to about 100 seconds, about 1 second to about 50 seconds, about 1 second to about 40 seconds, about 1 second to about 30 seconds, about 1 second to about 20 seconds, about 1 second to about 10 seconds, about 10 seconds to about 100 seconds, about 10 seconds to about 50 seconds, about 10 seconds to about 40 seconds, about 10 seconds to about 30 seconds, about 10 seconds to about 20 seconds, about 20 seconds to about 100 seconds, about 20 seconds to about 50 seconds, about 20 seconds to about 40 seconds, about 20 seconds to about 30 seconds, about 30 seconds to about 40 seconds, about 40 seconds to about 100 seconds, about 40 seconds to about 50 seconds, or about 50 seconds to about 100 seconds. 2 (nits) reaches 50% of the initial luminosity (T 50 In some embodiments, lighting devices prepared using the nanostructures of the present disclosure exhibit a brightness of 500 cd / m after about 19 seconds to about 35 seconds. 2 (nits) reaches 50% of the initial luminosity (T 50 ).

[0290]

[0301] In some embodiments, lighting devices prepared using the nanostructures of the present disclosure with fluoride in the shell exhibit a light intensity of 500 cd / m 2 Time to reach 50% of the initial luminous intensity (T 50 ) is the T of an electroluminescent device containing the corresponding nanostructure without any fluoride in the shell. 50 At least about three times longer than [Example]

[0291]

[0302] The following examples are illustrative, but not limiting, of the products and processes described herein. Suitable modifications and adaptations of the variety of conditions, formulations and other parameters normally encountered in the art and obvious to those skilled in the art in light of this disclosure are within the spirit and scope of the invention.

[0292] Example 1 ZnSe using TOPTe precursor 1-x Te x Synthesis of alloy nanocrystals

[0303] Preparation of TOPTe precursor: First, a Te precursor mixture was prepared by diluting trioctylphosphine telluride (1M Te, 230 μL) with 2.5 mL of dried, distilled oleylamine. To this solution, lithium triethylborohydride (1M in THF, 230 μL) was added, resulting in a deep purple solution. Finally, zinc oleate (0.5M in trioctylphosphine (TOP), 460 μL) was added, resulting in a colorless, opaque, viscous gel that could be drawn into a syringe.

[0293]

[0304] A 100 mL three-neck flask was charged with oleylamine (15 mL) and degassed under vacuum at 110 °C for 30 min. The mixture was then heated to 300 °C under a nitrogen flow. Once this temperature was reached, a solution of trioctylphosphine selenide (TOPSe, 2.7 mmol) and diphenylphosphine (225 μL) in TOP (2.9 mL total) was added to the flask. Once the temperature returned to 300 °C, a solution of the TOPTe precursor from above and diethylzinc (295 μL) in TOP (1 mL) was rapidly injected from another syringe. The temperature was set to 280 °C, and after 5 min, injection of a solution of diethylzinc (294 μL) and TOPSe (4.4 mmol) in TOP (3.8 mL total) was initiated at a rate of 0.5 mL / min until the complete addition of a total of 3.8 mL. After the precursor injection was complete, the reaction mixture was held at 280 °C for 5 min and then cooled to room temperature. The growth solution was diluted with an equal volume of toluene (40 mL), and the nanocrystals were precipitated by adding ethanol (120 mL). After centrifugation, the supernatant was discarded, and the nanocrystals were redispersed in hexane (5 mL). The concentration was measured as dry weight by evaporating the solvent from an aliquot. The dried material was further subjected to thermogravimetric analysis to determine the ZnSe content.

[0294] Example 2 Synthesis of ZnSe nanocrystals

[0305] ZnSe nanocrystals were prepared using the method of Example 1 without injection of the TOPTe precursor.

[0295] Example 3 ZnSe 1-x Te x / Synthesis of ZnSe buffer nanocrystals

[0306] ZnSe with an average diameter of 4.0 nm and a target shell thickness of four monolayers (ML) of ZnSe 1-x Te x A ZnSe buffer layer of nanocrystals was prepared.

[0296]

[0307] A three-necked flask (100 mL) was charged with zinc oleate (6.23 g), lauric acid (3.96 g), trioctylphosphine oxide (4.66 g), and TOP (9.4 mL). The flask was heated to 100 °C for 30 minutes and subjected to three vacuum and nitrogen refill cycles before degassing. The reaction mixture was placed under a nitrogen blanket and mixed with ZnSe with TOPSe (1.8 mL of 0.3 M selenium in TOP) 1-x Te x A solution of the core (4.0 mL, 28.0 mg / mL in hexane) was added to the flask. The flask was evacuated for 2 minutes and then heated to 310 °C under a nitrogen stream. When this temperature was reached, a slow injection of TOPSe (10.4 mL, 0.3 M in TOP) was started at a rate of 0.325 mL / min. After the end of the selenium injection, the reaction was held at 310 °C for 10 minutes and then cooled to room temperature. The reaction mixture was diluted with toluene (45 mL). Core / shell nanocrystals were precipitated by adding ethanol (135 mL) and then isolated by centrifugation, decantation of the supernatant, and redispersion of the nanocrystals in hexane (5 mL). This solution was filtered through a PTFE 0.22 μm syringe filter, and the concentration was measured as dry weight by evaporating the solvent from an aliquot. Thermogravimetric analysis was further performed on the dried material to determine the ZnSe content.

[0297] Example 4 ZnSe with fluoride passivation 1-x Te x / Synthesis of ZnSe buffer nanocrystals

[0308] The procedure was the same as the method outlined in Example 3, except that 0.78 millimoles of zinc fluoride, zirconium fluoride, or hafnium fluoride were added prior to the first three vacuum and nitrogen refill cycles.

[0298] Example 5 Synthesis of ZnSe / ZnSe Buffer Nanocrystals

[0309] A ZnSe buffer layer of ZnSe nanocrystals with an average diameter of 4.0 nm and a target shell thickness of four monolayers (ML) of ZnSe was prepared.

[0299]

[0310] A 500 mL three-necked flask was charged with zinc oleate (27.63 g), lauric acid (17.54 g), trioctylphosphine oxide (18.00 g), and TOP (36.0 mL). The flask was then heated to 100 °C for 30 minutes and subjected to three vacuum and nitrogen refill cycles before degassing. The reaction mixture was placed under a nitrogen blanket and a solution of ZnSe core (2.0 mL, 216.0 mg / mL in hexane) was added to the flask. The flask was evacuated for 2 minutes and then heated to 310 °C under a nitrogen flow. Once this temperature was reached, a slow injection of TOPSe (25.3 mL, 0.3 M in TOP) was started at a rate of 0.720 mL / min. After the end of the selenium injection, the reaction was held at 310 °C for 10 minutes and then cooled to room temperature. The reaction mixture was diluted with toluene (95 mL). The core / shell nanocrystals were precipitated by adding ethanol (190 mL) and then isolated by centrifugation, decantation of the supernatant, and redispersion of the nanocrystals in hexane (7 mL). This solution was filtered through a PTFE 0.22 μm syringe filter and the concentration was measured as dry weight by evaporating the solvent from an aliquot. Thermogravimetric analysis was further performed on the dried material to determine the ZnSe content.

[0300] Example 6 Synthesis of ZnSe / ZnSe Buffer Nanocrystals with Fluoride Passivation

[0311] The procedure was the same as the method outlined in Example 5, except that 3.0 mmol of zinc fluoride, zirconium fluoride, or hafnium fluoride was added prior to the first three vacuum and nitrogen refill cycles.

[0301] Example 7 ZnSe 1-x Te x Synthesis of / ZnSe / ZnS Core / Shell Nanocrystals

[0312] ZnSe with an average diameter of 6.1 nm having a target shell thickness of four monolayers (ML) of ZnS 1-x Te x A ZnS shell was prepared on the / ZnSe nanocrystals.

[0302]

[0313] A 25 mL three-necked flask was charged with zinc oleate (375 mg), lauric acid (240 mg), trioctylphosphine oxide (281 mg), and TOP (0.566 mL). The flask was then heated to 100 °C for 30 minutes and subjected to three vacuum and nitrogen refill cycles prior to degassing. The reaction mixture was placed under a nitrogen blanket and mixed with the ZnSe of Example 3 or 4 mixed with zinc oleate / TOPS (0.064 mL of 2.0 M sulfur in TOP + 0.254 mL of 0.5 M zinc oleate in TOP) 1-x Te xA solution of / ZnSe nanocrystals (0.30 mL, 216.0 mg / mL in hexane) was added to the flask. The flask was evacuated for 2 minutes and then heated to 310 °C under a nitrogen stream. Once this temperature was reached, slow injection of zinc oleate / TOPS (9.5 mL, 0.3 M in TOP) was initiated at a rate of 0.103 mL / min. After the sulfur injection was complete, the reaction was held at 310 °C for 10 minutes and then cooled to room temperature. The reaction mixture was diluted with toluene (5 mL). Core / shell nanocrystals were precipitated by adding ethanol (10 mL), and then isolated by centrifugation, decantation of the supernatant, and redispersion of the nanocrystals in hexane (5 mL). The precipitation was repeated once more with ethanol (10 mL), and the nanocrystals were finally redispersed in octane (3 mL). This solution was filtered through a PTFE 0.22 μm syringe filter, and after measuring the dry weight of an aliquot, the concentration was adjusted to 18 mg / mL.

[0303] Example 8 Synthesis of ZnSe / ZnSe / ZnS Core / Shell Nanocrystals

[0314] ZnSe 1-x Te x The procedure was the same as the method outlined in Example 7, except that the ZnSe / ZnSe nanocrystals of Example 5 or Example 6 were injected instead of the / ZnSe nanocrystals.

[0304] Example 9 Synthesis of ZnSe / ZnSe / ZnS Core / Shell Nanocrystals with Fluoride Passivation

[0315] The procedure was the same as the method outlined in Example 8, except that the flask was loaded with zinc fluoride anhydrous (1.94 mmol), or either 0.9 mmol of hafnium fluoride or zirconium fluoride prior to the first three vacuum and nitrogen refill cycles.

[0305] Example 10 ZnSe with Fluoride Passivation 1-x Te x / ZnSe / ZnS Core / Shell Nanocrystal Synthesis

[0316] The procedure was the same as the method outlined in Example 7, except that 3.0 millimoles of zinc fluoride, zirconium fluoride, or hafnium fluoride was added prior to the first three vacuum and nitrogen refill cycles.

[0306] Example 11 Synthesis of ZnSe / ZnSe / ZnS Core / Shell Nanocrystals with Increased Fluoride Passivation

[0317] The procedure was the same as the method outlined in Example 9, except that the flask was also charged with anhydrous zinc fluoride (634.0 mg) prior to the first three vacuum and nitrogen refill cycles.

[0307] Example 12 Optical Luminescence Properties of Nanocrystals Prepared Using Fluoride During the Shelling Reaction

[0318] Table 1 shows the solution photoluminescence spectra of ZnSe / ZnS core / shell and ZnSeTe / ZnSe / ZnS core / shell / shell quantum dots prepared in the presence of ZnF2 during the shelling reaction. As shown in Table 1, the resulting core / shell quantum dots with a sufficiently passivated surface exhibit a high quantum yield (QY) and a narrow full width at half maximum (FWHM).

[0308]

[0319] As shown in Table 1, by increasing the material loading of ZnF2 during the shelling reaction from 4 molar equivalents (Sample B) to 14 molar equivalents (Sample C), a good surface coating was obtained, unexpectedly resulting in a higher QY and a narrower FWHM.

[0309]

[0320] The incorporation of fluoride during shell growth also resulted in a change in the morphology of the ZnS-shelled quantum dots. Instead of the quasi-spherical particles synthesized using standard shell growth conditions (Figures 2 and 5), particles with a cubic shape were obtained in the presence of ZnF2, regardless of the loading level of ZnF2 (Figures 3, 4, and 6). These cubic particles also demonstrate significantly less roll-off at higher luminosities in electroluminescent devices. For example, Figure 7 is a scatter plot of external quantum efficiency (EQE) versus luminance (nit) for ZnSe / ZnS quantum dots (Sample A) with a standard ligand (not ZnF2), ZnSe / ZnS quantum dots treated with 4 molar equivalents of ZnF2 (Sample B), and ZnSe / ZnS quantum dots treated with 14 molar equivalents of ZnF2 (Sample C). The improved roll-off indicates improved surface passivation and electrochemical stability of the ZnF2 ligand.

[0310]

[0321] Furthermore, the presence of fluorine in the final core / shell quantum dots prepared in the presence of ZnF2 during the shelling reaction can be confirmed by X-ray photoelectron spectroscopy (XPS). Figure 8 shows the total atomic composition of Example B, where 1.9% of all atoms are fluorine and the measured F:Zn ratio is 0.13. Figures 9A and 9B compare the high-resolution XPS spectra of the fluorine 1s region between Sample A and Sample B. A significant signal for Sample B was observed in Figure 9B.

[0311]

Table 1

[0312] Example 13 Prepared electroluminescent device

[0322] The device was prepared by a combination of spin coating and thermal evaporation. First, a hole injection material poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) (50 nm) was spin-coated onto a UV-ozone treated indium tin oxide (ITO) substrate and baked at 200 °C for 15 minutes. The device was transferred into an inert atmosphere, and a hole transport material N,N'-di(naphthalen-1-yl)-N,N'-bis(4-vinylphenyl)biphenyl-4,4'-diamine (VNPB) (20 nm) was deposited by spin coating and baked at 200 °C for 15 minutes. A solution of either ZnSe / ZnS or ZnSe 1-x Te x / ZnSe / ZnS QD was deposited by spin coating (no resin was used in the light-emitting layer), followed by spin coating of an electron transport material ZnMgO (20 nm). Then, an Al cathode (150 nm) was deposited by thermal evaporation, and subsequently, the device was encapsulated using a cap-glass, getter, and epoxy resin.

[0313] Example 14 Electroluminescent characteristics of devices prepared using the quantum dots of Samples A - E

[0323] Table 2 shows the electroluminescence spectra of devices containing ZnSe / ZnS core / shell and ZnSeTe / ZnSe / ZnS core / shell / shell quantum dots (Samples A - E in Table 1) prepared in the presence of ZnF2 during the shelling reaction. As shown in Table 2, unexpectedly, the electroluminescent lifetime (T at 500 cd / m 2 2) increased by 2 - 6 times for the quantum dots prepared in the presence of ZnF2. 50 )

[0314]

[0324] As shown in Table 2, by increasing the material loading of ZnF2 during the shelling reaction from 4 molar equivalents (device by Sample B) to 14 molar equivalents (device by Sample C), a better surface coating was obtained and an unexpectedly longer lifetime was obtained.

[0315] [Table 2]

[0316] Example 15 Photoluminescent properties of nanocrystals prepared using different fluorides during the shelling reaction and electroluminescent properties of devices prepared therefrom

[0325] The solution photoluminescence spectra of ZnSe / ZnS core / shell and ZnSeTe / ZnSe / ZnS core / shell / shell quantum dots (samples A–E) prepared in the presence of ZnF during the shelling reaction and in the presence of other fluoride sources are shown in Table 3.

[0317] [Table 3]

[0318]

[0326] Table 4 shows the electroluminescence spectra of devices (devices A to I) containing the quantum dots of samples A to I in Table 3, respectively.

[0319] [Table 4]

[0320] Example 16 Photoluminescent properties of nanocrystals prepared using metal fluorides during the core-buffered growth / shell reaction and electroluminescent properties of devices prepared therefrom

[0327] The solution photoluminescence spectra of ZnSe / ZnS core / shell and ZnSeTe / ZnSe / ZnS core / shell / shell quantum dots prepared in the presence of Group IV fluorides during the core-buffered growth / shell reaction are shown in Table 5. As shown in Table 5, the resulting core / shell quantum dots with well-passivated surfaces exhibit high quantum yields (QY) and narrow full widths at half maximum (FWHM).

[0321] [Table 5]

[0322]

[0328] The electroluminescence spectra of devices containing ZnSe / ZnS core / shell quantum dots (Samples J and K in Table 5) are shown in Table 6. As shown in Table 6, the electroluminescent lifetime (T at 500 cd / m 2 in) 50 ) was significantly increased in the prepared quantum dots (devices by Sample K) in which ZrF4 was present in the core.

[0323]

Table 6

[0324] Example 17 Optical luminescence properties of nanocrystals prepared using metal fluorides during core buffer growth / shell reaction and electroluminescent properties of devices prepared therefrom

[0329] The solution quantum yields of ZnSe / ZnS core / shell quantum dots prepared in the presence of metal fluorides during core buffer growth / shell reaction, and the electroluminescence spectra of devices containing these quantum dots are shown in Table 7 (Figure 10).

[0325]

Table 7

[0326]

[0330] As shown in Table 7, retention of baseline EQE was observed in all ZnSe cores (Samples T - Y) treated with metal fluorides compared to the basic control sample P. In addition, a significant and unexpected increase in device lifetime (in the order of 2 - 5) was observed in Samples Q - S and W - Y in which metal fluorides were present in the shelling reaction. Furthermore, the combination of metal fluorides in both the core and shell results in excellent quantum dots with a longer operating lifetime of the electroluminescent device without compromising EQE (Samples W - Y).

[0327] Example 18 Quantum dot synthesis

[0331] The quantum dots used in Examples 19-25 were those described in U.S. Patent Application Publication No. 2017 / 0066965 (ZnSe / ZnS quantum dots), U.S. Patent Application Publication No. 2017 / 0306227 (InP / ZnSe / ZnS quantum dots), or U.S. Provisional Patent Application No. 62 / 677853 (ZnSe), which are incorporated by reference in their entireties. 1-x Te x ZnSe / ZnS quantum dots were synthesized using the procedure described in

[14] . The synthesized quantum dots were capped with zinc oleate ligands as their native ligands.

[0328] Example 19 TBAF and octylamine treatment of InP / ZnSe / ZnS quantum dots (Sample Z)

[0332] 10 mg of tetrabutylammonium fluoride trihydrate (TBAF), 13 mg of didodecyldimethylammonium chloride, and 8 mg of octylamine were dissolved in 1.8 mL of toluene. Green-emitting InP / ZnSe / ZnS quantum dots containing the native zinc oleate ligand (18 mg, 0.43 mL of a 42 mg / mL stock solution in octane) were added to this solution. The mixture was stirred for 60 min at 70 °C. The quantum dots containing the TBAF ligand were isolated by precipitation with acetonitrile (1.2 mL) and redispersed in octane (0.5 mL). This octane dispersion was used for optical characterization.

[0329] Example 20 Octylamine treatment of InP / ZnSe / ZnS quantum dots (sample AA)

[0333] 13 mL of dodecyldimethylammonium chloride and 8 mg of octylamine were dissolved in 1.8 mL of toluene. Green-emitting InP / ZnSe / ZnS quantum dots containing zinc oleate native ligands (18 mg, 0.43 mL of a stock solution in octane at 42 mg / mL) were added to this solution. The mixture was stirred at 70 °C for 60 minutes. The quantum dots obtained by precipitation using acetonitrile (1.2 mL) were isolated and redispersed in octane (0.5 mL). This octane dispersion was used for optical characterization.

[0330] Example 21 TBAF treatment of InP / ZnSe / ZnS quantum dots (Sample AB)

[0334] 10 mg of tetrabutylammonium fluoride trihydrate and 13 mg of dodecyldimethylammonium chloride were dissolved in 1.8 mL of toluene. Green-emitting InP / ZnSe / ZnS quantum dots containing zinc oleate native ligands (18 mg, 0.43 mL of a stock solution in octane at 42 mg / mL) were added to this solution. The mixture was stirred at 70 °C for 60 minutes. The quantum dots containing TBAF ligands were isolated by precipitation using acetonitrile (1.2 mL) and redispersed in octane (0.5 mL). This octane dispersion was used for optical characterization.

[0331] Example 22 Excess octylamine treatment of InP / ZnSe / ZnS quantum dots (Samples AC and AD)

[0335] An excess amount of octylamine (10 mg) was added to 0.1 mL of the final octane solution prepared in Example 19 (using TBAF and octylamine) and Example 20 (using octylamine only). These mixtures were used directly for optical characterization.

[0332] Example 23 Photoluminescence properties of nanocrystals after fluoride and / or amine treatment, and electroluminescent properties of devices prepared therefrom

[0336] The solution quantum yield, photoluminescence, and full width at half maximum values of InP / ZnSe / ZnS quantum dots prepared with and without fluoride treatment are shown in Table 8.

[0333] [Table 8]

[0334] Example 24 TBAF and octylamine treatment of InP / ZnSe / ZnS quantum dots (Sample AE)

[0337] 19 mg of TBAF, 13 mg of didodecyldimethylammonium chloride, and 8 mg of octylamine were dissolved in 1.8 mL of toluene. Red-emitting InP / ZnSe / ZnS QDs containing the native zinc oleate ligand (18 mg, 0.055 mL of a 325 mg / mL stock solution in octane) were added to this solution. The mixture was stirred for 120 min at 70 °C. The exchanged QDs were isolated by precipitation with acetonitrile (0.6 mL) and redispersed in octane (0.5 mL). This octane dispersion was used for optical characterization.

[0335] Example 25 Octylamine treatment of InP / ZnSe / ZnS quantum dots (sample AF)

[0338] Didodecyldimethylammonium chloride (13 mg) and octylamine (8 mg) were dissolved in toluene (1.8 mL). Red-emitting InP / ZnSe / ZnS QDs containing the native zinc oleate ligand (18 mg, 0.055 mL of a 325 mg / mL stock solution in octane) were added to this solution. The mixture was stirred for 120 min at 70 °C. The exchanged QDs were isolated by precipitation with acetonitrile (0.6 mL) and redispersed in octane (0.5 mL). This octane dispersion was used for optical characterization.

[0336] Example 26 TBAF treatment of InP / ZnSe / ZnS quantum dots (sample AG)

[0339] Tetrabutylammonium fluoride trihydrate (57 mg) and didodecyldimethylammonium chloride (39 mg) were dissolved in toluene (5.4 mL). Red-emitting InP / ZnSe / ZnS QDs (54 mg, 0.165 mL of a stock solution in octane at 325 mg / mL) containing native ligands of zinc oleate were added to this solution. The mixture was stirred at 70 °C for 120 minutes. The exchanged QDs were isolated by precipitation with acetonitrile (1.8 mL) and redispersed in octane (1.5 mL). This octane dispersion was used for optical characterization.

[0337] Example 27 Photoluminescence properties of nanocrystals after fluoride and / or amine treatment, and electroluminescent properties of devices prepared therefrom

[0340] Table 9 shows the values of solution quantum yield, photoluminescence, and full width at half maximum of InP / ZnSe / ZnS quantum dots prepared with and without fluoride treatment.

[0338]

Table 9

[0339]

[0341] Although various embodiments have been described above, it should be understood that they are presented by way of example only and are not limiting. It will be apparent to those skilled in the relevant art that various changes in form and detail can be made without departing from the spirit and scope of the invention. Accordingly, the scope should not be limited by any of the above exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

[0340]

[0342] All publications, patents, and patent applications mentioned in this specification are incorporated herein by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference, showing the level of skill of those skilled in the art relevant to the present invention.

Claims

1. A core comprising a nanocrystal core, At least one shell disposed on the core, A nanostructure comprising, The at least one shell contains ZnS and a fluoride, The molar ratio of the fluoride of the nanostructure to zinc in the nanostructure is 0.05 to 0.35, Nanostructure.

2. A core comprising a nanocrystal core, At least one shell disposed on the core, and The at least one shell contains ZnS and a fluoride, wherein the core is ZnSe １－ｘ Te ｘ and 0 ≤ x < 1 Nanostructure.

3. The at least one shell contains ZnSe, The nanostructure according to claim 1 or 2.

4. The at least one shell includes a first shell containing ZnSe, and a second shell containing ZnS and a fluoride, The nanostructure according to any one of claims 1 to 3.

5. The fluoride is in the form of a metal fluoride, ammonium fluoride or tetraalkylammonium fluoride, The nanostructure according to any one of claims 1 to 4.

6. wherein the fluoride is in the form of a metal fluoride containing ZnF ２ , HfF ４ or ZrF ４ ​ The nanostructure according to any one of claims 1 to 5.

7. The nanostructure is, A core containing ZnSe, and at least one shell containing ZnS and ZnF ２ and A core containing ZnSe, at least one shell containing ZnSe, and at least one shell containing ZnS and ZnF ２ and ZnSe １－ｘ Te ｘ (where 0 ≦ x < 1), a core containing the same, and ZnS and ZnF ２ at least one shell containing the same, or ZnSe １－ｘ Te ｘ (where 0 ≦ x < 1), a core containing Te, at least one shell containing ZnSe, and at least one shell containing ZnS and ZnF ２ at least one shell Comprising, The nanostructure according to any one of claims 1 to 6.

8. Further comprising at least one amine bonded to the surface of the nanostructure, The nanostructure according to any one of claims 1 to 7.

9. (a) Providing a nanocrystal core, (b) Optionally, mixing the core of (a) with a zinc source and a selenium source to provide a core having a ZnSe shell, (c) Mixing the core of (a) or the core having the ZnSe shell of (b) with a fluoride source, (d) Leaching a solution containing a zinc source and a sulfur source into the mixture of (c) Comprising, A method for preparing the nanostructure according to any one of claims 1 to ⑧.

10. ZnSe or ZnSe １－ｘ Te ｘ (where 0 ≦ x < 1) and a core containing a first metal fluoride, At least one shell disposed on the core, and The at least one shell contains ZnS and optionally a second metal fluoride, Nanostructure.

11. wherein the first metal fluoride contains ZnF ２ , HfF ４ or ZrF ４ . The nanostructure according to claim 10.

12. wherein the second metal fluoride is ZnF ２ , HfF ４ or ZrF ４ and includes The nanostructure according to claim 10 or 11.

13. The molar ratio of the fluoride of the nanostructure to zinc in the nanostructure is 0.05 to 0.35, The nanostructure according to any one of claims 10 to 12.

14. The nanostructure is, ZnSe and ZnF ２ , HfF ４ or ZrF ４ A core containing a metal fluoride containing ZnSe and ZnF ２ , HfF ４ or ZrF ４ At least one shell containing a metal fluoride containing ZnSe and ZnF ZnSe and ZnF ２ , HfF ４ or ZrF ４ A core containing a metal fluoride containing ZnSe, ZnF ２ , HfF ４ or ZrF ４ At least one shell containing a metal fluoride containing ZnSe, ZnF ZnSe and ZnF ２ , HfF ４ or ZrF ４ A core containing a metal fluoride including; and at least one shell containing ZnS; ZnSe and ZnF ２ , HfF ４ or ZrF ４ A core containing a metal fluoride containing; at least one shell containing ZnSe; and at least one shell containing ZnS; ZnSe １－ｘ Te ｘ (where 0 < x < 1) and ZnF ２ , HfF ４ or ZrF ４ a core containing a metal fluoride including; and ZnS and ZnF ２ , HfF ４ or ZrF ４ at least one shell containing a metal fluoride including; ZnSe １－ｘ Te ｘ (where 0 < x < 1) and ZnF ２ , HfF ４ or ZrF ４ A core containing a metal fluoride containing; at least one shell containing ZnSe; and ZnS and ZnF ２ , HfF ４ or ZrF ４ At least one shell containing a metal fluoride containing; ZnSe １－ｘ Te ｘ (where 0 < x < 1) and ZnF ２ , HfF ４ or ZrF ４ A core containing a metal fluoride containing; and at least one shell containing ZnS; or ZnSe １－ｘ Te ｘ (where 0 < x < 1) and ZnF ２ , HfF ４ or ZrF ４ a core containing a metal fluoride including; at least one shell containing ZnSe; and at least one shell containing ZnS Comprising, The nanostructure according to any one of claims 10 to 13.

15. Further comprising at least one amine bonded to the surface of the nanostructure, The nanostructure according to any one of claims 10 to 14.

16. To provide a nanostructure, (a) Mixing a solution of a zinc source, a selenium source, and a first metal fluoride source to provide a core comprising ZnSe or ZnSe １－ｘ Te ｘ (where 0 ≦ x < 1) and a first metal fluoride (b) Optionally, mixing the core of (a) with a zinc source and a selenium source to provide a core having a ZnSe shell; (c) Optionally, mixing the core of (a) or the core having the ZnSe shell of (b) with a second metal fluoride source; and (d) Leaching a solution containing a zinc source and a sulfur source into the mixture of (a), (b) or (c). Comprising: The method for preparing a nanostructure according to any one of claims 10 to 15.

17. The nanostructure exhibits a photoluminescence quantum yield of 60% to 99%, The nanostructure according to any one of claims 1 to 8, 10 to 15.

18. A core comprising a nanocrystal core, At least one shell containing ZnS or ZnSe disposed on the core, At least one fluoride bonded to the surface of the nanostructure, At least one amine bonded to the surface of the nanostructure, A nanostructure comprising: The molar ratio of the fluoride bonded to the nanostructure to the zinc in the nanostructure is 0.05 to 0.

35. Nanostructure.

19. The core contains InP, The nanostructure according to claim 18.

20. The at least one shell contains ZnSe, The nanostructure according to claim 18 or 19.

21. The at least one shell includes a first shell containing ZnSe and a second shell containing ZnS. The nanostructure according to any one of claims 18 to 20.

22. The fluoride is in the form of a metal fluoride, ammonium fluoride or tetraalkylammonium fluoride, The nanostructure according to any one of claims 18 to 21.

23. The fluoride is in the form of tetraalkylammonium fluoride, The nanostructure according to any one of claims 18 to 22.

24. The nanostructure includes a core containing InP, at least one shell containing ZnS, at least one shell containing ZnSe, tetraalkylammonium fluoride bonded to the surface of the nanostructure, and octylamine bonded to the surface of the nanostructure. The nanostructure according to any one of claims 18 to 23.

25. The nano-structure has a peak emission wavelength of 450 nm to 550 nm, The nano-structure according to any one of claims 18 to 24.

26. The nano-structure has a peak emission wavelength of 550 nm to 650 nm, The nano-structure according to any one of claims 18 to 25.

27. The nano-structure exhibits a photoluminescence quantum yield of 60% to 99%, The nano-structure according to any one of claims 18 to 26.

28. The nano-structure exhibits a photoluminescence quantum yield of 60% to 90%, The nano-structure according to any one of claims 18 to 27.

29. The nano-structure is a quantum dot, The nano-structure according to any one of claims 1 to 8, 10 to 15, 17 to 28.

30. A device comprising the nano-structure according to any one of claims 1 to 8, 10 to 15, 17 to 29.

31. A film comprising the nano-structure according to any one of claims 1 to 8, 10 to 15, 17 to 30 and at least one organic resin.

32. A molded article comprising the film according to claim 31.

33. To provide a nano-structure, (a) a nano-crystalline core and at least one shell containing ZnS or ZnSe disposed on the core, (b) at least one fluoride source, and (c) at least one amine source comprising mixing A method for preparing the nano-structure according to any one of claims 18 to 29.

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