CN116253354A - Nanoparticle, preparation method thereof and light-emitting diode - Google Patents
Nanoparticle, preparation method thereof and light-emitting diode Download PDFInfo
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- C01G1/00—Methods of preparing compounds of metals not covered by subclasses C01B, C01C, C01D, or C01F, in general
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
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- C01B19/04—Binary compounds including binary selenium-tellurium compounds
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- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/14—Carrier transporting layers
- H10K50/16—Electron transporting layers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
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- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/04—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction
- H01L33/06—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a quantum effect structure or superlattice, e.g. tunnel junction within the light emitting region, e.g. quantum confinement structure or tunnel barrier
Abstract
The embodiment of the application discloses a nanoparticle, a preparation method thereof and a light-emitting diode, and relates to the technical field of display, wherein the nanoparticle is of a core-shell structure, and the core-shell structure comprises an inner core, a transition layer coating the inner core and a shell coating the transition layer; the inner core comprises a first metal element and an oxygen element; the shell comprises a second metal element and a VI main group element; the transition layer comprises a first metal element, an oxygen element, a second metal element and a VI main group element; the contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same elements in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are not higher than the contents of the same elements in the outer shell. The application also provides a preparation method of the nanoparticle and a light-emitting diode based on the nanoparticle. The nanoparticle provided by the application is provided with the transition layer between the inner core and the outer shell, so that the crystal defects inside the nanoparticle are reduced, and the stability and the conductivity of the nanoparticle are improved.
Description
Technical Field
The application relates to the technical field of display, in particular to a nanoparticle, a preparation method thereof and a light-emitting diode.
Background
The light emitting diode (Light Emitting Diode, LED) is a solid semiconductor point light source device capable of converting electric energy into light energy, and the device structure comprises a hole transmission layer, a light emitting layer and an electron transmission layer, and achieves the effect of high-efficiency light emission by balancing electron and hole injection.
At present, the material of an electron transport layer in a light-emitting diode generally adopts metal oxide nano particles, the electron mobility of the metal oxide nano particles is higher, the metal oxide nano particles can play a role in electron transport and simultaneously play a role in blocking holes, excitons are limited in the light-emitting layer, and the light-emitting efficiency of the device is further improved. However, the stability of the metal oxide nano-particles is poor, and the performance fluctuation is obvious; meanwhile, crystal defects such as oxygen vacancies and surface defects existing in the metal oxide nanoparticles have a great influence on the performance of the device, and the performance of the device is easy to fluctuate. Therefore, improving the stability and conductivity properties of metal oxide nanoparticles as electron transport materials has become one of the keys to improve device performance.
Disclosure of Invention
Embodiments of the present application provide a nanoparticle having good stability and conductivity.
It is another object of embodiments of the present application to provide a method of preparing nanoparticles.
It is yet another object of an embodiment of the present application to provide a light emitting diode.
The technical scheme of the invention is as follows:
in a first aspect, an embodiment of the present application provides a nanoparticle, where the nanoparticle is a core-shell structure, and the core-shell structure includes an inner core, a transition layer coating the inner core, and an outer shell coating the transition layer;
the inner core comprises a first metal element and an oxygen element; the shell comprises a second metal element and a VI main group element; the transition layer comprises a first metal element, an oxygen element, a second metal element and a VI main group element;
the contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same elements in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are not higher than the contents of the same elements in the outer shell.
Optionally, in some embodiments of the present application, when the first metal element and the second metal element are different elements and the oxygen element and the VI main group element are different elements, the content of the first metal element and the oxygen element in the transition layer is respectively lower than the content of the same element in the core, and the content of the second metal element and the VI main group element in the transition layer is respectively lower than the content of the same element in the shell.
Optionally, in some embodiments of the present application, when the first metal element and the second metal element are the same element and the oxygen element and the VI main group element are different elements, the content of the oxygen element in the transition layer is lower than the content of the oxygen element in the core; the content of VI main group elements in the transition layer is lower than that of VI main group elements in the shell; or alternatively
When the oxygen element and the VI main group element are the same element and the first metal element and the second metal element are different elements, the content of the first metal element in the transition layer is lower than the content of the first metal element in the core; the content of the second metal element in the transition layer is lower than the content of the second metal element in the outer shell.
The contents of the first metal element and the second metal element in the transition layer are respectively lower than the contents of the same elements in the core or the shell.
Alternatively, in some embodiments of the present application, when the transition layer is of a single-layer structure, the content of the oxygen element in the transition layer decreases sequentially along the first direction; the content of VI main group elements in the transition layer is increased along the first direction in sequence;
the first direction is the direction from the core to the shell.
Optionally, in some embodiments of the present application, when the transition layer is a multilayer structure, the content of the first metal element and the oxygen element in each transition layer decreases sequentially along the first direction; the content of the second metal element and the VI main group element in each transition layer is increased along the first direction;
The first direction is the direction from the core to the shell.
Optionally, in some embodiments of the present application, the first metal element includes one or more of zinc element, tin element, and indium element.
Optionally, in some embodiments of the present application, the first metal element further includes a doping element, and the doping element is selected from one or more of an aluminum element, a magnesium element, and a lithium element.
Optionally, in some embodiments of the present application, a ratio of the doping element in the first metal element of the core is within 30%.
Optionally, in some embodiments of the present application, the content of the doping element in the transition layer is lower than the content of the doping element in the core.
Optionally, in some embodiments of the present application, the thickness of the transition layer is 2-5 nm; and/or
The diameter of the inner core is 4-20 nm; and/or
The thickness of the shell layer is 1-3 nm.
Optionally, in some embodiments of the present application, the surface of the shell is bound with a surface ligand selected from one or more of a sulfhydryl compound, an amino alkane compound, and an amino alcohol compound.
Optionally, in some embodiments of the present application, the first metal element is selected from one or more of zinc element, tin element, indium element; and/or the second metal element is selected from one or more of zinc element, copper element, magnesium element, aluminum element and gallium element.
In a second aspect, the present application also provides a method for preparing nanoparticles, comprising:
providing a first metal element source, an alkali solution, a second metal element source and a VI main group element source, wherein the first metal element source provides a first metal element; the alkali solution provides oxygen element, and the second metal element source provides second metal element; a VI main group element source providing a VI main group element;
providing a core, wherein the core comprises a first metal element and a second metal element;
performing transition layer growth on the surface of the inner core by using a first metal element source, an alkali solution, a second metal element source and a VI main group element source to obtain an intermediate solution; and
based on the intermediate solution, performing shell growth by using a second metal element source and a VI main group element source to obtain a nanoparticle solution;
the contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same elements in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are not higher than the contents of the same elements in the outer shell.
Alternatively, in some embodiments of the present application, when the transition layer has a single layer structure, the first metal element and the second metal element are the same, the amount of the oxygen element for the growth of the transition layer per unit time gradually decreases, and the amount of the VI main group element for the growth of the transition layer per unit time gradually increases.
Optionally, in some embodiments of the present application, when the transition layer is a multilayer structure, the transition layer grows, including:
mixing a first metal element source, an alkali solution, a second metal element source and a VI main group element source with the inner core in a fractional manner so as to sequentially grow a transition layer on the surface of the inner core;
wherein the amounts of the first metal element and the oxygen element used for growing each transition layer are gradually reduced; the amount of the second metal element, VI main group element, used for growing each transition layer gradually increases.
Optionally, in some embodiments of the present application, after performing the shell growth reaction, further comprising:
providing a surface ligand; and
mixing the surface ligand with the nanoparticle solution at 50-180 ℃ for reaction for 10-90 min;
wherein the surface ligand is selected from one or more of sulfhydryl compounds, amino alkane compounds and amino alcohol compounds.
In a third aspect, the present application further provides a light emitting diode, comprising an electron transport layer, the material of the electron transport layer comprising the nanoparticle provided in the first aspect or the nanoparticle prepared by the method for preparing the nanoparticle provided in the second aspect.
The nanoparticle provided by the embodiment of the application has a core-shell structure comprising a core, a transition layer and a shell, wherein the core is coated by the transition layer and the shell, so that the stability of the core is improved; meanwhile, the transition layer comprising elements contained in the inner core and elements contained in the outer shell is arranged between the inner core and the outer shell of the nanoparticle, so that the crystal lattice of the nanocrystalline formed by the inner core material of the nanoparticle gradually transits to the crystal lattice of the nanocrystalline formed by the outer shell material, the lattice mutation is reduced, the crystal defect in the nanoparticle is reduced, and the stability and the conductivity of the nanoparticle are improved.
The application also provides a preparation method of the nanoparticle, so as to obtain the nanoparticle comprising a core, a transition layer and a shell, wherein the composition of the nanoparticle is partially or completely changed from the core to the shell.
The application also provides a light-emitting diode, which adopts the nano particles as the material of the electron transport layer, and improves the external quantum efficiency and the service life of the light-emitting diode by utilizing the characteristics of good stability and high conductivity of the nano particles.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the specific embodiments of the present application, and it is apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
The embodiment of the application provides a nanoparticle, a preparation method thereof and a light-emitting diode. The following will describe in detail. The following description of the embodiments is not intended to limit the preferred embodiments. In addition, in the description of the present application, the term "comprising" means "including but not limited to". The terms first, second, third and the like are used merely as labels, and do not impose numerical requirements or on the order of construction. Various embodiments of the invention may exist in a range of forms; it should be understood that the description in a range format is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; accordingly, the description of a range should be considered to have specifically disclosed all possible sub-ranges as well as single numerical values within that range. For example, a description of a range from 2 to 5 should be considered to have specifically disclosed sub-ranges, such as from 2 to 3, from 2 to 4, from 2 to 5, from 3 to 4, from 3 to 5, etc., as well as single numbers within the recited range, such as 2, 3, 4, and 5, as applicable regardless of the range. In addition, whenever a numerical range is referred to herein, it is meant to include any reference number (fractional or integer) within the indicated range.
In a first aspect, the present application provides a nanoparticle, where the nanoparticle is a core-shell structure, the core-shell structure including an inner core, a transition layer coating the inner core, and an outer shell coating the transition layer;
the inner core comprises a first metal element and an oxygen element; the shell comprises a second metal element and a VI main group element; the transition layer comprises a first metal element, an oxygen element, a second metal element and a VI main group element;
the contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same elements in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are not higher than the contents of the same elements in the outer shell.
The contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same element in the core, and the following are included: "the same element" is understood in this application as: a first metal element, an oxygen element; the "same element" in "the content of the second metal element, VI main group element in the transition layer is not higher than the content of the same element in the outer shell" is understood in this application as: a second metal element, a VI main group element. The first metal element and the second metal element may be the same or different; the VI main group element and the oxygen element can be the same or different; however, when the first metal element and the second metal element are the same element, the VI main group element cannot be an oxygen element at the same time; also, when the VI main group element is an oxygen element, the first metal element cannot be the same element as the second metal element.
In some embodiments, when the first metal element and the second metal element are different elements and the oxygen element and the VI main group element are different elements, the contents of the first metal element and the oxygen element in the transition layer are respectively lower than the contents of the same element in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are respectively lower than the contents of the same element in the outer shell.
Wherein when the first metal element and the second metal element are different and the VI main group element is selected from one or more of sulfur element, selenium element, and tellurium element, the content of the first metal element in the transition layer is lower than the content of the element in the core and higher than the content of the element in the shell, the content of the oxygen element in the transition layer is lower than the content of the element in the core and higher than the content of the element in the shell, the content of the VI main group element in the transition layer is lower than the content of the element in the shell and higher than the content of the element in the core, and the content of the second metal element in the transition layer is higher than the content of the element in the core and lower than the content of the element in the shell. In the direction from the inner core to the outer shell of the nanoparticle, the content of oxygen elements in the inner core, the transition layer and the outer shell respectively decrease in sequence, the content of VI main group elements in the inner core, the transition layer and the outer shell respectively increase in sequence, the content of first metal elements in the inner core, the transition layer and the outer shell respectively decrease in sequence, and the content of second metal elements in the inner core, the transition layer and the outer shell respectively increase in sequence.
In some embodiments, when the first metal element and the second metal element are the same element and the oxygen element and the VI main group element are different elements (i.e., the VI main group element is an oxygen element), the content of the oxygen element in the transition layer is lower than the content of the oxygen element in the core; the content of the VI main group element in the transition layer is respectively lower than that of the VI main group element in the shell.
Wherein when the first metal element and the second metal element are the same, the VI main group element is selected from one or more of sulfur element, selenium element and tellurium element, and the content of the VI main group element in the transition layer is lower than the content of the element in the shell and higher than the content of the element in the core; the content of oxygen element in the transition layer is lower than the content of the element in the inner core and higher than the content of the element in the outer shell; in the direction from the inner core to the outer shell of the nanoparticle, the content of VI main group elements in the inner core, the transition layer and the outer shell respectively decreases in sequence, and the content of second metal elements in the inner core, the transition layer and the outer shell respectively increases in sequence.
In some embodiments, when the oxygen element and the VI main group element are the same element, and the first metal element and the second metal element are different elements, the content of the first metal element and the second metal element in the transition layer is lower than the content of the same element in the core or the shell, respectively.
When the VI main group element selects oxygen element, the first metal element and the second metal element are different, and the content of the second metal element in the transition layer is higher than the content of the element in the inner core and lower than the content of the element in the outer shell; the content of the first metal element in the transition layer is lower than the content of the element in the inner core and higher than the content of the element in the outer shell; the contents of the first metal element in the core, the transition layer and the shell respectively decrease in sequence in the direction from the core to the shell of the nanoparticle, and the contents of the second metal element in the core, the transition layer and the shell respectively increase in sequence.
The transition layer is arranged between the core and the shell of the nanoparticle, meanwhile, the contents of elements contained in the shell are gradually increased from the core to the shell respectively, and the contents of elements contained in the core are gradually reduced from the core to the shell respectively, so that the lattice of each layer of structure of the nanoparticle is gradually changed from the core to the shell, the lattice mutation between the core and the shell is improved, the crystal defects in the nanoparticle are reduced, and the stability and the conductivity of the nanoparticle are improved; meanwhile, the shell and the transition layer can protect the kernel, so that the stability of the kernel is further improved.
In the present application, the transition layer may have a single-layer structure or a multilayer structure. When the transition layer is of a multi-layer structure, each transition layer is sequentially coated on the outer side of the inner core.
In some embodiments, when the transition layer is a single-layer structure, the first metal element and the second metal element are the same, the content of the oxygen element in the transition layer decreases in the first direction in sequence; the content of VI main group elements in the transition layer is increased along the first direction in sequence; the first direction is the direction from the core to the shell.
The nano particles adopt a transition layer that the content of oxygen element gradually increases from one side close to the inner core to one side close to the outer shell and the content of VI main group element gradually increases from one side close to the inner core to one side close to the outer shell, so that the component content from the inner core of the nano particles to the outer shell is changed more smoothly, the crystal lattice smooth transition from the inner core to the outer shell is realized, the crystal lattice mutation of the core-shell structure of the nano particles is further reduced, the crystal lattice defect inside the nano particles is reduced, and the stability and the electric conductivity of the nano particles are improved.
In some embodiments, when the transition layer is a multilayer structure; the contents of the first metal element and the oxygen element in each transition layer are sequentially increased along the first direction; the contents of the second metal element and the VI main group element in each transition layer are sequentially reduced along the first direction; the first direction is the direction from the core to the shell.
The transition layers with gradually changing component contents exist between the inner core and the outer shell of the nanoparticle, so that the crystal lattice of the inner core of the nanoparticle is smoothly transited to that of the outer shell, the crystal lattice mutation of the core-shell structure of the nanoparticle is further reduced, the crystal lattice defect in the nanoparticle is reduced, and the stability and the conductivity of the nanoparticle are improved.
In some embodiments, the diameter of the inner core is 4-20 nm, so that the metal oxide formed by the first metal element and the oxygen element has better stability and higher conductivity, the problem that the film forming property of the nano particles is influenced due to overlarge particle size of the nano particles caused by overlarge inner core is avoided, the stability of the device based on the nano particles is further influenced, the problem that the band gap of the nano particles is too wide due to overlarge inner core is also avoided, the conductivity is reduced, and the electron transport layer based on the nano particles cannot meet the conductivity requirement of the device is avoided.
In some embodiments, the thickness of the transition layer is 2-5nm, avoiding that the particle size of the nanoparticle is too large because the transition layer is too thick, resulting in a decrease in the conductivity of the nanoparticle, affecting the conductivity of the electron transport layer based on the nanoparticle; and meanwhile, the aim of improving the lattice mutation problem of the inner core and the outer shell can be avoided because the transition layer is too thin.
In some embodiments, when the transition layers are a multi-layer structure, each transition layer has a thickness of 1-3 nm. It should be noted that the thickness of each transition layer may be the same or different.
In some embodiments, the thickness of the shell is 1-3 nm, so that the stability of the core and the conductivity of the nano particles are ensured, and the purpose of protecting the core from environmental influences is achieved.
In some embodiments, the surface of the shell has surface ligands bound thereto, the surface ligands being selected from one or more of sulfhydryl compounds, aminoalkyl compounds, amino alcohol compounds.
Wherein, the mercapto compound can be selected from mercaptan, propanethiol, hexanethiol, octanethiol, nonanethiol, decanethiol, undecanethiol, dodecanethiol, tridecanethiol, tetradecanethiol, hexadecanethiol, octadecanethiol, mercaptoethanol, mercaptopropanol, mercaptohexanol and other mercapto compounds; the chemical general formula of the amino alkane compound is NH 2 -R1, wherein R1 may be selected from alkyl groups such as n-propyl, isopropyl, methyl, ethyl, phenyl, benzyl, etc.; the amino alcohol compound may be selected from amino butanol, amino propanol, amino ethanol, etc. having an amino group and an alcoholic hydroxyl group.
The cations corresponding to the metal elements on the surface of the shell are combined with surface ligands which are easy to form stable covalent bonds with the cations, such as sulfhydryl compounds, amino alkane compounds, amino alcohol compounds and the like, and the surface ligands are not easy to fall off; the passivation of defects on the nanoparticle shell is effectively improved, suspension bonds on the surface of the nanoparticle shell are reduced, and the influence of the external environment on the inner core is reduced.
In some embodiments, the first metal element includes one or more of zinc (Zn), tin (Sn), indium (In). The material of the inner core can be metal oxide such as ZnO, snO, znSnO, znInO, inO.
In some embodiments, the first metal element further comprises a doping element selected from one or more of aluminum (Al), magnesium (Mg), lithium (Li). Doping elements are doped in the core to form a composite metal oxide with the metal oxide, such as: znMgO, znAlO, znLiO, inMgO, znSnMgO, etc.
In some embodiments, the doping element is present in the first metal element of the core at a ratio of less than 30% to avoid an excessive content of doping element in the nanoparticle affecting the conductivity of the nanoparticle.
In some embodiments, the content of the doping element in the transition layer is lower than the content of the doping element in the core, so that the content of the doping element in the core, the transition layer and the shell also accords with the rule of gradual decrease in sequence, the lattice defect in the nanoparticle is reduced, and the stability and the conductivity of the nanoparticle are improved.
In some embodiments, when the transition layer includes a multi-layer structure, the content of the doping element in each transition layer decreases in sequence along the first direction, so that the content of the doping element in the transition layer conforms to the rule of decreasing in sequence along the first direction, and the lattice transition from the inner core to the outer shell of the nanoparticle is smoother, thereby improving the stability and conductivity of the nanoparticle.
In some embodiments, the second metal element is selected from one or more of zinc element, copper element (Cu), magnesium element, aluminum element, gallium element (Ga).
In a second aspect, the present application also provides a method for preparing nanoparticles, comprising:
providing a core, a first metal element source, an alkali solution, a second metal element source and a VI main group element source;
providing a first metal element source, an alkali solution, a second metal element source and a VI main group element source, wherein the first metal element source provides a first metal element; the alkali solution provides oxygen element, and the second metal element source provides second metal element; a VI main group element source providing a VI main group element;
providing a core, wherein the core comprises a first metal element and a second metal element;
performing transition layer growth on the surface of the inner core by using a first metal element source, an alkali solution, a second metal element source and a VI main group element source to obtain an intermediate solution; and
Based on the intermediate solution, performing shell growth by using a second metal element source and a VI main group element source to obtain a nanoparticle solution;
the contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same elements in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are not higher than the contents of the same elements in the outer shell. The first metal element source is a solution capable of providing the first metal element, and is selected from one or more of Zn source solution containing Zn source, sn source solution containing Sn source and In source solution containing In source. Wherein, zn source can be selected from zinc acetate, zinc sulfate, zinc chloride, zinc palmitate, zinc stearate, zinc bromide and other compounds capable of providing zinc ions; the Sn source can be selected from tin chloride, tin acetate, tin sulfate, tin bromide, tin nitrate and other compounds capable of providing tin ions; the In source may be selected from indium sulfate, indium trichloride, trimethylindium, triethylindium, indium nitrate, indium acetate, and other compounds that can provide indium ions.
In some embodiments, the first metal element source further comprises one or more of an Al source solution containing an Al source, an Mg source solution containing an Mg source, and a Li source solution containing a Li source. Wherein, the Al source can be selected from aluminum acetate, aluminum sulfate, aluminum chloride, aluminum bromide and other compounds capable of providing aluminum ions; the Mg source can be selected from magnesium acetate, magnesium sulfate, magnesium chloride, magnesium bromide, magnesium dicyclopentadiene and other compounds capable of providing aluminum ions; the Li source may be selected from lithium acetate, lithium nitrate, lithium chloride, and other compounds that can provide lithium ions.
The second metal element source is a solution capable of providing a second metal element, and is selected from one or more of Zn source solution containing Zn source, cu source solution containing Cu source, mg source solution containing Mg source, al source solution containing Al source and Ga source solution containing Ga source. Wherein one or more of a Sn source solution containing a Sn source and an In source solution containing an In source. Wherein, zn source can be selected from zinc acetate, zinc sulfate, zinc chloride, zinc palmitate, zinc stearate, zinc bromide and other compounds capable of providing zinc ions; the Cu source can be selected from copper acetate, copper sulfate, copper chloride, copper bromide, copper stearate and other compounds capable of providing copper ions; the Mg source can be selected from magnesium acetate, magnesium sulfate, magnesium chloride, magnesium bromide, magnesium dicyclopentadiene and other compounds capable of providing aluminum ions; the Al source can be selected from aluminum acetate, aluminum sulfate, aluminum chloride, aluminum bromide and other compounds capable of providing aluminum ions; the Ga source may be selected from gallium sulfate, gallium trichloride, gallium tribromide, gallium acetate, and other compounds that provide gallium ions.
Wherein the VI main group element source is selected from one or more of alkali solution, sulfur source solution containing sulfur source, selenium source solution containing selenium source and tellurium source solution containing tellurium source. Wherein the alkaline solution is conventional in the art, such as potassium hydroxide solution, sodium hydroxide solution; the sulfur source can be selected from elemental sulfur or sulfur-containing compounds; the selenium source can be selected from selenium simple substance or selenium-containing compound; the tellurium source may be selected from elemental tellurium or a compound containing tellurium.
In the present application, the first metal element source, the alkali solution, the second metal element source, and the VI main group element source each include a solvent. Wherein the solvent can be one or more of ethanol, propanol, butanol, octadecene, dodecane and octane. Further, the alkali solution and the solvent in the VI main group element source can be respectively alcohol solutions such as ethanol, propanol, butanol and the like; the solvent of the first metal element source and the second metal element source can be one or more of ethanol, propanol, butanol, octadecene, dodecane and octane respectively.
In some embodiments, the core may be provided commercially, and may be prepared by the following methods:
providing a first metal element source and an alkaline solution;
mixing the first metal element and the alkali solution, and performing kernel growth to obtain kernel solution.
The obtained kernel solution can be directly used for mixing with a first metal element source, an alkali solution, a second metal element source and a VI main group element source to perform a transition layer growth reaction; the obtained core solution can also be mixed with a first metal element source, an alkali solution, a second metal element source and a VI main group element source after the core is obtained through separation, so as to carry out a transition layer growth reaction.
When the first metal element provided by the first metal element source and the second metal element provided by the second metal element source are the same, the solute used by the first metal element source and the solute used by the second metal element source may be the same or different, and preferably the solute used by the first metal element source and the solute used by the second metal element source are the same. When the source of the VI main group element is an alkali solution, the solutes employed by the alkali solution and the source of the VI main group element may be the same or different, preferably the same. Wherein the solute in the first metal element source is a compound that provides the first metal element; the solute in the second metal element source is a compound that provides the second metal element; the solute in the alkali solution is alkali; the solute in the VI main group element is a compound that provides the VI main group element.
In some embodiments, when the transition layer is in a single-layer structure, in the growth of the transition layer, the first metal element source, the alkali solution, the second metal element source and the VI main group element source are uniformly mixed with the inner core, and the transition layer is grown on the surface of the inner core to obtain an intermediate solution.
Wherein the mole ratio of the solute in the first metal element source to the solute in the second metal element source is 3:1-1:3; the molar ratio of the alkali solution to the solute in the VI main group element source is 3:1-1:3, so that the crystal lattice of the nanocrystalline formed by the formed transition layer material is positioned between the crystal lattice of the nanocrystalline formed by the inner core material and the crystal lattice of the nanocrystalline formed by the outer shell material, and the crystal lattice mutation of the crystal lattice of the nanocrystalline formed by the inner core material and the crystal lattice of the nanocrystalline formed by the outer shell material is smaller, and the gradual transition of the crystal lattice of the obtained nanoparticle is realized.
In some embodiments, in the transition layer growth reaction, the first metal element source, the alkali solution, the second metal element source, and the VI main group element source are mixed with the core solution at a constant speed within 15-30 min; when the first metal element source, the alkali solution, the second metal element source and the VI main group element source are injected into the core solution at a constant speed, the injection speed of the first metal element source, the alkali solution, the second metal element source and the VI main group element source is 0.02-0.1 mL/min. The amounts of the first metal element source, the alkali solution, the second metal element source, and the VI main group element source injected into the core solution per minute may be scaled up or down in equal proportion according to the reaction scale.
In some embodiments, in the shell growth reaction, the second metal element source and the VI main group element are mixed with the intermediate solution at a constant speed within 15-30 minutes; when the second metal element source and the VI main group element source are injected into the intermediate solution at a constant speed, the injection speed of the second metal element source and the VI main group element source is 0.02-0.1 mL/min. The amounts of the second metal element source and the VI main group element source injected into the intermediate solution per minute may be scaled up or down in equal proportion according to the reaction scale.
In some embodiments, in the transition layer growth reaction, the concentrations of the first metal element source, the alkali solution, the second metal element source and the VI main group element source may be 0.05 to 5mol/L, respectively, so that separate nucleation due to excessive concentration is avoided, and meanwhile, the reaction speed is ensured, and the preparation efficiency of the nanoparticles is improved.
In some embodiments, in the shell growth reaction, the concentration of the second metal element source and the VI main group element source is 0.05-5 mol/L, respectively, so that separate nucleation caused by the excessive concentration of the second metal element source and the VI main group element source is avoided, and meanwhile, the preparation efficiency of the nanoparticles is ensured.
In some embodiments, when the transition layer is a single layer structure and the first metal element and the second metal element are the same, the amount of oxygen element for the growth of the transition layer per unit time gradually decreases and the amount of VI main group element for the growth of the transition layer per unit time gradually increases.
It should be noted that: the amount of oxygen element for the growth of the transition layer per unit time gradually decreases and the amount of VI main group element for the growth of the transition layer per unit time gradually increases, and it should be understood that: the speed of adding the solute in the alkaline solution into the solution of the inner core is gradually reduced, and the speed of adding the solute in the VI main group element source into the solution of the inner core is gradually increased, so that the oxygen element content in the obtained transition layer is gradually reduced from the side close to the inner core to the side far from the inner core, and the VI main group element content in the transition layer is gradually increased from the side close to the inner core to the side far from the inner core.
The contents of oxygen elements and VI main group elements in the transition layer of the obtained nano particles gradually change from one side close to the inner core to one side far from the inner core by controlling the addition speed change of the alkali solution and VI main group element sources in unit time, so that the gradual transition of the crystal lattice of the nano crystals from the inner core of the nano particles to the outer shell is realized, the problem of the crystal lattice mutation of the nano particles is further improved, and the stability and the electric conductivity of the nano particles are improved.
In some embodiments, when the transition layer is a multilayer structure, the transition layer is grown, including:
mixing a first metal element source, an alkali solution, a second metal element source and a VI main group element source with the inner core in a fractional manner so as to sequentially grow a transition layer on the surface of the inner core;
wherein the amounts of the first metal element and the oxygen element used for growing each transition layer are gradually reduced; the amount of the second metal element, VI main group element, used for growing each transition layer gradually increases.
Namely: the amount of solute in the first metal element source for mixing with the core is gradually reduced each time, the amount of solute in the alkaline solution for mixing with the core is gradually reduced each time, the amount of solute in the second metal element source for mixing with the core solution is gradually increased each time, and the amount of solute in the group VI main group element source for mixing with the core is gradually increased each time.
When the metal elements supplied from the first metal element source and the second metal element source are the same, the sum of the amounts of the first metal element supplied from the first metal element source and the second metal element source mixed with the core each time is unchanged, the amount of the VI main group element source mixed with the core each time is gradually increased, and the amount of the alkali solution mixed with the core each time is gradually decreased. The first metal element source and the second metal element source may use the same solute, that is, the first metal element source and the second metal element source may be provided by the first metal element source or the second metal element source. When the VI main group element provided by the VI main group element source is an oxygen element, the sum of the amounts of the VI main group element source and the oxygen element provided by the alkali solution for growing the transition layer, which are mixed with the core each time, is unchanged, the amount of the second metal element source, which is mixed with the core each time, is gradually increased, and the amount of the first metal element source, which is mixed with the core each time, is gradually decreased. The main group element source and the alkali solution can adopt the same solute, namely oxygen element can be provided by adopting the alkali solution, and VI main group element source can also be provided.
In some embodiments, after performing the shell growth reaction, further comprising:
Providing a surface ligand;
providing a surface ligand; and
mixing the surface ligand with the nanoparticle solution at 50-180 ℃ for reaction for 10-90 min;
wherein the surface ligand is selected from one or more of sulfhydryl compounds, amino alkane compounds and amino alcohol compounds.
In the shell growth process of the nano-particles, a ligand provided by a solvent, a metal element source (such as a second metal element source) and a non-metal element source (such as a VI main group element source) in a reaction system, such as hydroxyl and carboxyl, can be combined with cations on the shell surfaces of the nano-particles to cover the surfaces of the nano-particles. However, the binding force between the ligands and cations is weak, so that stable surface ligands are difficult to form on the surfaces of the nanoparticles, the surface passivation effect on the nanoparticles is weak, more dangling bonds are formed on the surfaces of the nanoparticles, and the stability of the nanoparticles is affected. Therefore, the surface ligand exchange reaction is adopted, and the thiol compound, the amino alkane compound and the amino alcohol compound are used for exchanging ligands such as hydroxyl, carboxyl and the like combined in the preparation process of the shell, so that the nano-particle taking the thiol, the amino alkane and the amino alcohol as the surface ligands is obtained, and the surface of the nano-particle is passivated due to the fact that the thiol compound, the amino alkane compound and the amino alcohol compound have strong binding force with cations on the surface of the shell and are not easy to fall off, the cationic dangling bond on the surface of the nano-particle is reduced, and the stability of the nano-particle is further improved.
In a third aspect, the present application further provides a light emitting diode, comprising an electron transport layer, the material of the electron transport layer comprising the nanoparticle provided in the first aspect or the nanoparticle prepared by the method for preparing the nanoparticle provided in the second aspect.
The light emitting diode can be a positive light emitting diode or an inverted light emitting diode. When the light emitting diode is a forward light emitting diode, the forward light emitting diode comprises an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and a cathode which are arranged in a stacked manner, wherein the anode is arranged on the substrate; when the light emitting diode is an inverted light emitting diode, the inverted light emitting diode comprises a cathode, an electron transport layer, a light emitting layer, a hole transport layer, a hole injection layer and an anode which are stacked, and the cathode is arranged on the substrate.
Wherein the anode material may be selected from one or more of ITO, FTO, ZTO, IZO, IGZO; the cathode material may be selected from one or more of Al, ag, au, cu, mo, mg, al and alloys thereof; the substrate may be a rigid substrate or a flexible substrate. Wherein the rigid substrate can be selected from one or more of glass and metal foil; the flexible substrate is selected from one or more of polyethylene terephthalate (PET), polyethylene terephthalate (PEN), polyether ether ketone (PEEK), polystyrene (PS), polyether sulfone (PES), polycarbonate (PC), polyarylate (PAT), polyarylate (PAR), polyimide (PI), polyvinyl chloride (PV), polyethylene (PE), polyvinylpyrrolidone (PVP) and textile fiber.
The nano particles provided by the application are suitable for electroluminescent devices provided with electron transport layers, such as organic light-emitting diodes, inorganic light-emitting diodes, high polymer light-emitting diodes, quantum dot light-emitting diodes and the like. Among them, metal oxides are commonly used as the material of the electron transport layer of the quantum dot light emitting diode. The zinc oxide nano particles in the metal oxide can provide good electron transmission capability and hole blocking capability because of high electron mobility and wide band gap of deep ultraviolet light emission, and become the most common electron transmission layer material of the current quantum dot light emitting diode. However, zinc oxide is a metal oxide, and is liable to cause lattice defects, and is inferior in stability, and particularly in zinc oxide nanoparticles, and its performance is more unstable, so how to maintain stability of zinc oxide nanoparticles and other metal oxide nanoparticles, and reduce surface defects thereof is one of the keys to improve the performance of QLEDs based on zinc oxide nanoparticles and other metal oxide nanoparticles. Because the quantum dot light emitting diode is used as an emerging display technology, the service life and the device performance of the quantum dot light emitting diode do not completely meet the commercialized requirements, and the nanoparticle and the preparation method thereof provided by the application have a pushing effect on the quantum dot light emitting diode to meet the commercialized requirements.
When the light emitting diode is an inorganic light emitting diode, the material of the light emitting layer is an inorganic material. The inorganic material can be selected from ZnS: mn, znS: tb/CdS, and SiO 2 :Ge、SiO 2 :Er、SrS:Ce、CaGa 2 S 4 :Ce、SrGa 2 S 4 :Ce、SrS:Cu、GaN、ZnS:Tm、Zn 2 SiO 2 Ca or other phosphors; here, "means doping; "/" indicates cladding.
When the light emitting diode is an organic light emitting diode, the material of the light emitting layer is a small molecular organic material. The small molecular organic material can be selected from 4- (dinitrilomethyl) -2-butyl-6- (1, 7-tetramethyl julolidine-9-vinyl) -4H-pyran (DCJTB), 9, 10-di (beta-naphthyl) Anthracene (ADN), 4 '-bis (9-ethyl-3-carbazole vinyl) -1,1' -biphenyl (BCzVBi) or 8-hydroxyquinoline aluminum or other small molecular organic luminescent materials.
When the light emitting diode is a polymer light emitting diode, the material of the light emitting layer is a polymer organic material. The polymer organic material can be selected from poly-p-styrenevinylene, polythiophene, polyaniline, polycarbazole or other polymer organic luminescent materials.
When the light emitting diode is a quantum dot light emitting diode, the material of the light emitting layer is a quantum dot material. The quantum dot material can be CdS, cdSe, cdTe, znO, znS, znSe, znTe, gaAs, gaP, gaSb, hgS, hgSe, hgTe, inAs, inP, inSb, alAs, alP, cuInS, cuInSe and alloy or other quantum dot luminescent materials thereof.
The hole injection layer and the hole transport layer of the light emitting diode can be made of small molecular organic matters or high molecular conductive polymers, and TFB, PVK, TCTA, TAPC, TPD, poly-TPD and Poly-TBP, PFB, NPB, CBP, PEODT can be specifically selected: PSS, woO 3 、MoO 3 、NiO、V 2 O 5 Other hole transport materials such as HATCN and CuS.
In order that the details and operation of the present invention may be clearly understood by those skilled in the art, the present invention will be described below with reference to several examples, which illustrate the above technical solutions, and the nanoparticles, the preparation methods thereof, and the advanced performance of the corresponding light emitting diodes according to the embodiments of the present invention.
Example 1
The preparation of the nano-particles specifically comprises the following steps:
s1, adding 2mmol of potassium hydroxide into 30mL of butanol, and dissolving to obtain a potassium hydroxide solution; adding 6mmol of zinc acetate into the potassium hydroxide solution, and stirring for 2 hours to obtain a clear solution, so as to obtain a core solution;
s2, uniformly injecting 1.5mL of Na with concentration of 1mol/L into the kernel solution within 20min 2 Se ethanol solution and 1.5mL of potassium hydroxide ethanol solution with the concentration of 1mol/L are stirred to react to obtain clear solution and intermediate solution;
s3, 1mL of Na with concentration of 1mol/L is injected into the intermediate solution 2 Se ethanol solution is stirred for 1h to obtain clear solution, and nanoparticle solution is obtained; separating to obtain nano particles, dispersing the nano particles in butanol and preserving; or drying the nano particles to obtain nano particle powder for storage.
The light emitting diode will be prepared on the day of the preparation of the above nanoparticles by the following method:
depositing ITO on a glass substrate to obtain an anode with the thickness of 40 nm;
depositing PEDOT on ITO in an air environment, and then heating at 150 ℃ for 15min to obtain a hole injection layer, wherein the thickness of the hole injection layer is 20nm;
in a glove box in a nitrogen environment, depositing TFB on the hole injection layer, and then heating at 150 ℃ for 30min to obtain a hole transport layer, wherein the thickness of the hole transport layer is 30nm;
depositing CdZnSeS red quantum dots on the hole transport layer in a glove box in a nitrogen environment, and then heating at 100 ℃ for 5min to obtain a light-emitting layer, wherein the thickness of the light-emitting layer is 20nm;
depositing the nano particles on the light-emitting layer in a glove box in a nitrogen environment, and then heating at 80 ℃ for 30min to obtain an electron transport layer, wherein the thickness of the electron transport layer is 30nm;
evaporating silver on the electron transport layer to serve as a cathode, wherein the thickness of the cathode is 100nm; and packaging to obtain the light emitting diode A.
And (3) after the prepared nano particles are stored for 30 days in a nitrogen environment, preparing the light-emitting diode B by adopting the same method as the preparation of the light-emitting diode A.
Example 2
In this example, propanethiol is added to the nanoparticle solution obtained in S3, and stirred at 50 ℃ for 1 hour to obtain a nanoparticle solution with converted surface ligands, and nanoparticles with converted surface ligands are separated and stored in a butanol solution; the remainder was the same as in example 1. And the surface ligand-converted nanoparticle obtained in this example was prepared to obtain light emitting diode C by the same method as that of light emitting diode a in example 1.
And the nanoparticle with the converted surface ligand obtained in this example was left under nitrogen atmosphere for 30 days, and then light emitting diode D was prepared by the same method as that of light emitting diode a in example 1.
Example 3
In this example, the propanethiol added in example 2 was replaced with 1-aminopropanol, and the remainder was the same as in example 2. And the surface ligand-converted nanoparticle obtained in this example was prepared to obtain a light emitting diode E by the same method as that of the light emitting diode a in example 1.
Example 4
The preparation of the nano-particles specifically comprises the following steps:
s1, adding 6mmol of potassium hydroxide into 30mL of butanol, and dissolving to obtain a potassium hydroxide solution; adding 2mmol of zinc acetate into the potassium hydroxide solution, and stirring for 2 hours to obtain a clear solution, so as to obtain a core solution;
s2, uniformly injecting 1.5mL of 1mol/L magnesium-ethanol solution and 1.5mL of 1mol/L zinc acetate butanol solution into the inner core solution within 20min, and stirring and reacting to obtain a clear solution to obtain an intermediate solution;
s3, injecting 1mL of 1mol/L magnesium-ethanol solution into the intermediate solution, and stirring for 1h to obtain a clear solution, thus obtaining a nanoparticle solution; separating to obtain the nano particles.
The nanoparticle obtained in this example was prepared to obtain a light emitting diode F by the same method as that of the light emitting diode a in example 1.
Example 5
The preparation of the nano-particles specifically comprises the following steps:
s1, adding 2mmol of potassium hydroxide into 30mL of butanol, and dissolving to obtain a potassium hydroxide solution; adding 2mmol of zinc acetate into the potassium hydroxide solution, and stirring for 2 hours to obtain a clear solution, so as to obtain a core solution;
s2, 1.5mL of 1 mol/L-concentration magnesium-dicyclopentadiene ethanol solution, 1.5mL of 1 mol/L-concentration zinc acetate ethanol solution and 1.5mL of 1 mol/L-concentration Na are uniformly injected into the inner core solution within 20min 2 Se ethanol solution and 1.5mL of potassium hydroxide ethanol solution with the concentration of 1mol/L are stirred to react to obtain clear solution and intermediate solution;
s3, injecting 1mL of 1mol/L magnesium-dicyclopentadiene ethanol solution and 1.5mL of 1mol/L Na into the intermediate solution 2 Se ethanol solution is stirred for 1h to obtain clear solution, and nanoparticle solution is obtained; separating to obtain the nano particles.
The nanoparticle obtained in this example was prepared to obtain a light emitting diode G by the same method as that of the light emitting diode a in example 1.
Example 6
In this example, 1.5mL of Na having a concentration of 1mol/L was injected into the core solution in S2 within 20 minutes 2 Se ethanol solution and 1.5mL of 1mol/L potassium hydroxide ethanol solution, wherein Na 2 The injection rate of Se ethanol solution gradually increased and the injection rate of potassium hydroxide ethanol solution gradually decreased, and the rest was the same as in example 1, to prepare nanoparticles. And the nanoparticle obtained in this example was prepared to obtain a light emitting diode H by the same method as that of the light emitting diode a in example 1.
Example 7
In this example, 1.5mL of Na at a concentration of 1mol/L was added to S2 2 Se ethanol solution and 1.5mL of 1mol/L potassium hydroxide ethanol solution are injected into the kernel solution at constant speed for three times, after each injection, the solution is stirred until the solution is clarified, an intermediate solution is obtained, and the rest is the same as in example 1, so that the nano particles are prepared. And the nanoparticle obtained in this example was prepared to obtain a light emitting diode I by the same method as that of the light emitting diode a in example 1.
Example 8
In this example, in S2, na in example 1 2 The Se ethanol solution was replaced with an ethanol solution of elemental sulfur, the potassium hydroxide ethanol solution was replaced with a sodium hydroxide butanol solution, the zinc acetate was replaced with zinc palmitate, and the rest was the same as in example 1, to prepare nanoparticles. And the nanoparticle obtained in this example was prepared to obtain a light emitting diode J by the same method as that of the light emitting diode a in example 1.
Example 9
The preparation of the nano-particles specifically comprises the following steps:
s1, adding 6mmol of potassium hydroxide into 30mL of butanol, and dissolving to obtain a potassium hydroxide solution; adding 1.6mmol of zinc acetate and 0.4mmol of gallium chloride into a potassium hydroxide solution, and stirring for 2 hours to obtain a clear solution to obtain a core solution;
s2, uniformly injecting 1.5mL of 1mol/L magnesium dichloride ethanol solution, 1.2mL of 1mol/L zinc acetate butanol solution and 0.3mL of 1mol/L gallium chloride butanol solution into the inner core solution within 20min, and stirring to react to obtain a clear solution to obtain an intermediate solution;
s3, injecting 1mL of 1mol/L magnesium-ethanol solution into the intermediate solution, and stirring for 1h to obtain a clear solution, thus obtaining a nanoparticle solution; separating to obtain the nano particles.
The nanoparticle obtained in this example was prepared by the same method as that of the light emitting diode a in example 1 to obtain a light emitting diode K.
Comparative example
The preparation of the nano particle ZnO/ZnSe specifically comprises the following steps:
s1, adding 2mmol of potassium hydroxide into 30mL of butanol, and dissolving to obtain a potassium hydroxide solution; adding 6mmol of zinc acetate into the potassium hydroxide solution, and stirring for 2 hours to obtain a clear solution, so as to obtain a core solution;
s2, uniformly injecting 2.5mL of Na with concentration of 1mol/L into the kernel solution within 20min 2 And (3) stirring the Se ethanol solution to react to obtain a clear solution, and obtaining a nano particle ZnO/ZnSe solution.
Light emitting diode DB1 will be prepared by the same method as that of light emitting diode a in example 1 on the same day that the above nanoparticles were prepared.
The nanoparticles prepared above were stored for 30 days under a nitrogen atmosphere, and light emitting diode DB2 was prepared by the same method as that of light emitting diode a in example 1.
The device properties of the light emitting diodes obtained in examples 1 to 9 and comparative example were respectively tested, and the test results thereof are shown in table 1, wherein the property test of the devices of the light emitting diode a obtained in example 1 and the light emitting diode C obtained in example 2 and the light emitting diode DB1 obtained in comparative example included the property test performed on the day of preparation and the property test after 30 days of storage in air. Where t95@1000nit denotes the time required for the luminance of the device to decay to 95% at a luminance of 1000 nit.
As can be seen from table 1, compared with a light emitting diode obtained by using a nanoparticle as an electron transport layer material, which is not provided with a transition layer between the inner cores and the outer shells, the light emitting diode obtained by using the nanoparticle as an electron transport layer material has higher external quantum efficiency and longer service life, and therefore, the composition of the transition layer between the inner cores and the outer shells of the nanoparticle can improve the conductivity and the stability of the nanoparticle, and further improve the external quantum efficiency and the service life of the light emitting diode based on the nanoparticle. In addition, after the ligands such as the mercapto compound, the amino alkane compound and the like with strong binding force with the surfaces of the nano particles are exchanged by the organic ligands such as hydroxyl, carboxyl and the like with weak binding force with the surfaces of the nano particles, the external quantum efficiency and the working life of the light-emitting diode based on the nano particles are further improved, meanwhile, the external quantum efficiency and the working life of a device obtained by preparing the light-emitting diode after the nano particles are placed for 30 days are not obviously reduced, and the external quantum efficiency and the working life of the light-emitting diode obtained by preparing the light-emitting diode are not obviously reduced after the nano particles are placed for 30 days.
The above description is made in detail of a nanoparticle, a preparation method thereof and a light emitting diode provided in the embodiments of the present application, and specific examples are applied herein to illustrate principles and embodiments of the present application, where the above description of the examples is only for helping to understand the method and core ideas of the present application; meanwhile, as those skilled in the art will vary in the specific embodiments and application scope according to the ideas of the present application, the contents of the present specification should not be construed as limiting the present application in summary.
Claims (16)
1. The nanoparticle is characterized by being of a core-shell structure, wherein the core-shell structure comprises an inner core, a transition layer coating the inner core and an outer shell coating the transition layer;
the inner core comprises a first metal element and an oxygen element; the shell comprises a second metal element and a VI main group element; the transition layer comprises the first metal element, the oxygen element, the second metal element and the VI main group element;
the contents of the first metal element and the oxygen element in the transition layer are not higher than the contents of the same elements in the inner core, and the contents of the second metal element and the VI main group element in the transition layer are not higher than the contents of the same elements in the outer shell.
2. The nanoparticle according to claim 1, wherein when the first metal element and the second metal element are different elements and the oxygen element and the VI main group element are different elements, the contents of the first metal element and the oxygen element in the transition layer are respectively lower than the contents of the same element in the core; the contents of the second metal element and the VI main group element in the transition layer are respectively lower than the contents of the same element in the shell.
3. The nanoparticle according to claim 1, wherein when the first metal element and the second metal element are the same element and the oxygen element and the VI main group element are different elements, the content of the oxygen element in the transition layer is lower than the content of the oxygen element in the core; the content of the VI main group element in the transition layer is lower than that of the VI main group element in the shell; or alternatively
When the oxygen element and the VI main group element are the same element and the first metal element and the second metal element are different elements, the content of the first metal element in the transition layer is lower than the content of the first metal element in the core; the content of the second metal element in the transition layer is lower than the content of the second metal element in the outer shell.
4. A nanoparticle according to claim 3, wherein when the transition layer is of a single layer structure, the content of the oxygen element in the transition layer decreases in the first direction in sequence; the content of the VI main group element in the transition layer is sequentially increased along a first direction;
the first direction is a direction from the core to the shell.
5. The nanoparticle according to claim 1, wherein when the transition layer is a multilayer structure, the contents of the first metal element and the oxygen element in each of the transition layers decrease in sequence along a first direction; the contents of the second metal element and the VI main group element in each transition layer are sequentially increased along a first direction;
the first direction is a direction from the core to the shell.
6. The nanoparticle according to claim 1, wherein the first metal element comprises one or more of zinc, tin, indium.
7. The nanoparticle according to claim 1, wherein the first metal element further comprises a doping element selected from one or more of an aluminum element, a magnesium element, and a lithium element.
8. The nanoparticle according to claim 7, wherein the doping element is present in the first metal element of the core at a ratio of less than 30%.
9. Nanoparticle according to claim 1, wherein the thickness of the transition layer is 2-5 nm, and/or
The diameter of the inner core is 4-20 nm, and/or
The thickness of the shell layer is 1-3 nm.
10. The nanoparticle of claim 1, wherein the surface of the shell has a surface ligand attached thereto, the surface ligand being selected from one or more of a thiol compound, an aminoalkyl compound, and an amino alcohol compound.
11. The nanoparticle according to claim 1, wherein the first metal element is selected from one or more of zinc, tin, indium; and/or the second metal element is selected from one or more of zinc element, copper element, magnesium element, aluminum element and gallium element.
12. A method of preparing nanoparticles comprising:
providing a first metal element source, an alkali solution, a second metal element source and a VI main group element source, wherein the first metal element source provides a first metal element; the alkali solution provides an oxygen element, and the second metal element source provides a second metal element; the VI main group element source provides a VI main group element;
Providing a core, wherein the core comprises the first metal element and the second metal element;
performing transition layer growth on the surface of the inner core by using the first metal element source, the alkali solution, the second metal element source and the VI main group element source to obtain an intermediate solution; and
based on the intermediate solution, performing shell growth by using the second metal element source and the VI main group element source to obtain a nanoparticle solution;
the content of the first metal element and the oxygen element in the transition layer is not higher than the content of the same element in the inner core, and the content of the second metal element and the VI main group element in the transition layer is not higher than the content of the same element in the outer shell.
13. The method of producing nanoparticles according to claim 12, wherein when the transition layer has a single-layer structure, the first metal element and the second metal element are the same, the amount of oxygen element for growth of the transition layer per unit time gradually decreases, and the amount of VI main group element for growth of the transition layer per unit time gradually increases.
14. The method of preparing nanoparticles according to claim 12, wherein when said transition layer is a multilayer structure, said transition layer grows, comprising:
Mixing the first metal element source, the alkali solution, the second metal element source and the VI main group element source with the inner core in a fractional manner so as to sequentially grow the transition layer on the surface of the inner core;
wherein the amounts of the first metal element and the oxygen element for growing each of the transition layers are gradually reduced; the amounts of the second metal element, the VI main group element, for growing each of the transition layers gradually increase.
15. The method of preparing nanoparticles according to claim 12, further comprising, after performing the shell growth reaction:
providing a surface ligand; and
mixing surface ligand and the nanoparticle solution at 50-180 ℃ for reaction for 10-90 min;
wherein the surface ligand is selected from one or more of sulfhydryl compounds, amino alkane compounds and amino alcohol compounds.
16. A light emitting diode comprising an electron transport layer, wherein the material of the electron transport layer comprises the nanoparticle of any one of claims 1 to 11 or the nanoparticle produced by the method of producing the nanoparticle of any one of claims 12 to 15.
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| CN202111497071.3A Pending CN116253354A (en) | 2021-12-09 | 2021-12-09 | Nanoparticle, preparation method thereof and light-emitting diode |
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| US20140117311A1 (en) * | 2012-10-29 | 2014-05-01 | Juanita N. Kurtin | Semiconductor structure having nanocrystalline core and nanocrystalline shell pairing with compositional transition layer |
| CN106082352B (en) * | 2016-06-03 | 2018-07-20 | 中南大学 | A kind of FeAsO4/Fe2O3Composite material and preparation method and application |
| CN110752319B (en) * | 2018-07-24 | 2021-05-28 | Tcl科技集团股份有限公司 | Core-shell nano material, preparation method thereof and quantum dot light-emitting diode |
| CN112625674B (en) * | 2019-09-24 | 2022-04-29 | Tcl科技集团股份有限公司 | Composite material, quantum dot light-emitting diode and preparation method thereof |
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