WO2025200513A1 - 量子点材料及其制备方法、发光器件、显示面板 - Google Patents

量子点材料及其制备方法、发光器件、显示面板

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Publication number
WO2025200513A1
WO2025200513A1 PCT/CN2024/134546 CN2024134546W WO2025200513A1 WO 2025200513 A1 WO2025200513 A1 WO 2025200513A1 CN 2024134546 W CN2024134546 W CN 2024134546W WO 2025200513 A1 WO2025200513 A1 WO 2025200513A1
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WIPO (PCT)
Prior art keywords
quantum dot
dot material
solution
core structure
size
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PCT/CN2024/134546
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English (en)
French (fr)
Inventor
朱云柯
高宇南
裴琛
朱友勤
陈卓
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Peking University
BOE Technology Group Co Ltd
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Peking University
BOE Technology Group Co Ltd
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Priority to CN202480002761.2A priority Critical patent/CN121079381A/zh
Publication of WO2025200513A1 publication Critical patent/WO2025200513A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00Nanooptics, e.g. quantum optics or photonic crystals
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00Luminescent materials, e.g. electroluminescent or chemiluminescent
    • C09K11/02Use of particular materials as binders, particle coatings or suspension media therefor
    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00Luminescent materials, e.g. electroluminescent or chemiluminescent
    • C09K11/08Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials
    • C09K11/88Luminescent materials, e.g. electroluminescent or chemiluminescent containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements

Definitions

  • the quantum dot material has a size in a first direction, a size in a second direction, and a size in a third direction, wherein the first direction, the second direction, and the third direction are perpendicular to each other.
  • the ratio of the size of the quantum dot material in the first direction to the size of the quantum dot material in the third direction is in a range of 2.8 to 6; and/or the ratio of the size of the quantum dot material in the second direction to the size of the quantum dot material in the third direction is in a range of 2.8 to 6.
  • the fluorescence peak of the core structure has a wavelength range of 440 nm to 510 nm.
  • the core structure has a size in a first direction, a size in a second direction, and a size in a third direction, wherein a ratio of the size of the core structure in the first direction to the size of the core structure in the third direction is in a range of 6.5 to 15.75; and/or a ratio of the size of the core structure in the second direction to the size of the core structure in the third direction is in a range of 6.5 to 15.75.
  • the size range of the core structure in the first direction is 7.8nm to 12.6nm
  • the size range in the second direction is 7.8nm to 12.6nm
  • the size range in the third direction is 0.8nm to 1.2nm; wherein the first direction, the second direction and the third direction are perpendicular to each other.
  • the core structure includes: 4 selenium atomic layers and 5 cadmium zinc atomic layers, and the selenium atomic layers and the cadmium zinc atomic layers are alternately distributed along the third direction.
  • the core structure is a sphalerite crystal structure.
  • the X-ray diffraction imaging diagram there are three peaks at twice the incident angle of the X-ray of the core structure, located at: 24° to 30°, 43° to 46°, and 50° to 54°.
  • the wavelength of the fluorescence peak of the quantum dot material becomes shorter as x decreases.
  • the material of the shell structure includes at least one of ZnS, ZnSe, ZnSeS, and CdS.
  • a shell structure encapsulates the core structure.
  • the quantum dot material is in a quantum well structure.
  • the quantum dot material further includes: a ligand group, wherein the ligand group includes: a group of at least one of oleic acid, 1-octanethiol, 2-ethyl-hexanethiol, 1-decanethiol, 1-dodecanethiol, tributylphosphine selenide and 1-octadecene selenide connected to the shell structure through a chemical bond.
  • a method for preparing a quantum dot material comprising: dispersing CdSe quantum wells in a first organic solvent to obtain a first solution; adding zinc halide to the first solution to obtain a second solution; adding a phosphorus source ligand and a fatty amine to the second solution to obtain a third solution; stirring the third solution to obtain a fourth solution after reaction; adding a first polar solvent to the fourth solution to obtain a core structure of the quantum dot material, wherein a material of the core structure comprises: Cd x Zn (1-x) Se, wherein 1>x ⁇ 0.15; and forming a shell structure, wherein the shell structure encapsulates the core structure to obtain a quantum dot material, wherein the wavelength range of the fluorescence peak of the quantum dot material is 510nm to 540nm.
  • the CdSe quantum well in the first solution, includes: 4 layers of selenium atoms and 5 layers of cadmium atoms, and the selenium atomic layers and the cadmium atomic layers are alternately distributed; in the second solution, the ratio of the mass of the zinc halide to the mass of the CdSe quantum well is in the range of 3 to 32; and the second solution is stirred under vacuum conditions in the temperature range of 80°C to 100°C; in the third solution, the ratio of the volume of the first organic solvent to the volume of the phosphorus source ligand is in the range of 2.5 to 30, and the ratio of the volume of the first organic solvent to the volume of the fatty amine is in the range of 5 to 150; the stirring of the third solution is carried out in an inert gas atmosphere and at a temperature range of 200°C to 280°C.
  • the zinc halide comprises at least one of zinc iodide, zinc chloride, and zinc bromide.
  • the phosphorus source ligand includes at least one of tri-n-octylphosphine, tributylphosphine, and trioctylphosphine oxide; and/or the fatty amine includes at least one of oleylamine and octylamine.
  • the first organic solvent comprises at least one of 1-octadecene, paraffin oil, and olive oil.
  • the first polar solvent comprises at least one of ethanol, methanol, acetonitrile, and acetone.
  • forming the shell structure includes: dispersing an anion precursor in a second organic solvent to obtain a fifth solution; wherein the ratio of the volume of the anion precursor to the volume of the second organic solvent is in a range of 2 ⁇ 10 -3 to 28 ⁇ 10 -3 , and the anion in the anion precursor includes at least one of S and Se; and dispersing the obtained core structure Cd x Zn (1-x) Se in a first non-polar solvent to obtain a sixth solution.
  • the sixth solution is added to a third organic solvent, and a cationic precursor and oleic acid are added to obtain a seventh solution; and the seventh solution is stirred under vacuum conditions in a temperature range of 90°C to 100°C; wherein the ratio of the volume of the third organic solvent to the volume of the sixth solution is in a range of 2.5 to 15; the ratio of the volume of the third organic solvent to the volume of the oleic acid is in a range of 2.5 to 30; and the cation in the cationic precursor includes at least one of Zn and Cd.
  • the fifth solution is added to the seventh solution to obtain an eighth solution after reaction; a second polar solvent is added to the eighth solution to obtain the quantum dot material, and the wavelength range of the fluorescence peak of the quantum dot material is 510nm to 540nm.
  • the anion precursor includes at least one of 1-octanethiol, 2-ethylhexylthiol, 1-decanethiol, 1-dodecanethiol, tributylphosphine selenide, and 1-octadecene selenide.
  • the cationic precursor includes at least one of zinc acetate, zinc oleate, zinc stearate, zinc laurate, cadmium acetate, and cadmium oleate.
  • the first non-polar solvent comprises at least one of n-hexane, octane, and dodecane.
  • the fifth solution is added to the seventh solution under an inert gas atmosphere at a temperature ranging from 280° C. to 320° C., and the reaction time ranges from 30 minutes to 90 minutes.
  • a light-emitting device which includes: a first electrode and a second electrode arranged opposite to each other, and a light-emitting layer located between the first electrode and the second electrode; wherein the light-emitting layer includes: the quantum dot material described in any of the above embodiments.
  • a display panel includes: a light-emitting device as described in any one of the above embodiments and a pixel driving circuit; the pixel driving circuit is used to drive the light-emitting device to emit light.
  • FIG1 is a structural diagram of a display device according to some embodiments of the present disclosure.
  • FIG2 is a structural diagram of a display panel according to some embodiments of the present disclosure.
  • FIG3 is another structural diagram of a display panel according to some embodiments of the present disclosure.
  • FIG4 is a structural diagram of a light emitting device according to some embodiments of the present disclosure.
  • FIG5 is a structural diagram of a core structure formed by reacting a CdSe quantum well with a zinc halide according to some embodiments of the present disclosure
  • FIG6 is an X-ray diffraction image of a CdSe quantum well according to some embodiments of the present disclosure
  • FIG7 is an X-ray diffraction image of a Cd x Zn (1-x) Se core structure according to some embodiments of the present disclosure
  • FIG8 is a flow chart of a method for preparing a Cd x Zn (1-x) Se core structure according to some embodiments of the present disclosure
  • FIG9 is a flow chart of a method for preparing a shell structure according to some embodiments of the present disclosure.
  • the light emitting device 130 includes a first electrode 131 , a light emitting layer 132 , and a second electrode 133 that are sequentially stacked.
  • the light-emitting layer 132 includes a quantum dot material, for example, a quantum dot material in a quantum well structure, also known as a nanosheet. Due to its sheet-like shape, the quantum dot material in the quantum well structure experiences quantum confinement in one dimension.
  • the one-dimensional longitudinal direction here refers to the direction in which the thickness of the quantum dot material is located.
  • Quantum dot materials with quantum well structures are subject to quantum confinement in one dimension, meaning that the exciton activity in this quantum dot material is limited by particle size. Compared to non-quantum well structures, such as spherical quantum dot materials, the excitons in these materials are randomly oriented. However, due to the fact that the exciton activity in this quantum dot material is limited by particle size in one dimension, the direction of the excitons in the quantum dot material can be controlled, resulting in a higher luminous intensity.
  • the CdSe quantum dot material in the quantum well structure is called a CdSe quantum well 20.
  • CdSe quantum well 20 can cover the visible light region due to the number of atomic layers.
  • the emission wavelength range of a three-layer CdSe quantum well 20 is 458nm to 462nm
  • the emission wavelength of a four-layer CdSe quantum well 20 is 510nm to 515nm
  • the emission wavelength of a five-layer CdSe quantum well 20 is 550nm to 553nm.
  • the adjacent selenium atomic layer 210 and cadmium atomic layer 300 are called a CdSe quantum well 20.
  • a crown inorganic protective layer or a shell inorganic protective layer is usually grown on the surface of the CdSe quantum well 20 core structure.
  • the crown inorganic protective layer or the shell inorganic protective layer covers the defects on the surface of the CdSe quantum well 20, thereby improving the fluorescence quantum yield of the quantum dot material.
  • the fluorescence quantum yield of the four-layer CdSe quantum well 20 is increased to 100% by growing a ZnCdS protective shell layer on its surface.
  • the core-shell CdSe/ZnCdS quantum well increases in one longitudinal dimension, causing the exciton recombination emission wavelength of the CdSe/ZnCdS quantum well to redshift.
  • the emission wavelength of the CdSe/ZnCdS quantum well exceeds 600 nm, and light emitted with a wavelength greater than 600 nm is red.
  • a crown-shaped inorganic protective layer is grown on the sides of the CdSe quantum well 20. Because the crown-shaped inorganic protective layer is grown only on the sides of the CdSe quantum well 20, it does not alter the quantum confinement effect of the excitons within the CdSe quantum well 20, thereby avoiding any impact on the emission wavelength of the CdSe quantum well 20. This method can effectively improve the fluorescence quantum yield of the CdSe quantum well 20.
  • the crown-shaped inorganic protective layer only passivates the side defects of the CdSe quantum well 20.
  • the upper and lower surface defects of the CdSe quantum well 20 rely on the passivation effect of organic (such as carboxylic acid) ligands. In an electro-induced environment, the organic ligands are prone to fall off, and thus cannot effectively passivate the defects on the upper and lower surfaces of the CdSe quantum well 20, thereby affecting the luminescence performance of the CdSe quantum well 20.
  • an embodiment of the present disclosure provides a quantum dot material 40, wherein the quantum dot material 40 has a core-shell structure, wherein the material of the core structure includes: CdxZn (1-x) Se, wherein 1>x ⁇ 0.15, and the wavelength range of the fluorescence peak of the quantum dot material 40 is 510nm ⁇ 540nm.
  • the quantum dot material 40 includes a core structure and a shell structure 42 .
  • the core structure includes Cd x Zn (1-x) Se, and the shell structure 42 wraps the core structure to form the quantum dot material 40 .
  • the quantum dot material 40 is in a quantum well structure.
  • the wavelength of the fluorescence peak of the Cd x Zn (1-x) Se core structure 30 becomes shorter as x decreases.
  • the doping amount of cadmium atoms 31 refers to the ratio of the number of moles of cadmium atoms 31 to the sum of the number of moles of zinc atoms 32 and cadmium atoms 31.
  • the doping amount of zinc atoms 32 refers to the ratio of the number of moles of zinc atoms 32 to the sum of the number of moles of zinc atoms 32 and cadmium atoms 31.
  • the wavelength of the fluorescence peak of the CdxZn (1-x) Se core structure 30 is blue-shifted due to the doping of zinc atoms 32. Moreover, as the doping amount of zinc atoms 32 increases, the wavelength of the fluorescence peak of the CdxZn (1-x) Se core structure 30 becomes shorter.
  • an embodiment of the present disclosure provides a quantum dot material 40 including a cadmium selenide/zinc alloy core structure.
  • the wavelength range of the fluorescence peak of the quantum dot material 40 including the cadmium selenide/zinc alloy core structure is 510nm ⁇ 540nm, so as to be applied to provide a light-emitting device 130 that emits green light.
  • the fluorescence peak of the core structure has a wavelength ranging from 440 nm to 510 nm.
  • the core structure has a dimension in a first direction X, a dimension in a second direction Y, and a dimension in a third direction Z, wherein the first direction X, the second direction Y, and the third direction Z are perpendicular to each other.
  • the dimension of the Cd x Zn (1-x) Se core structure 30 in the first direction X is one of the length and the width of the Cd x Zn (1-x) Se core structure 30
  • the dimension of the Cd x Zn (1-x) Se core structure 30 in the second direction Y is the other of the length and the width of the Cd x Zn (1-x) Se core structure 30
  • the dimension of the Cd x Zn (1-x) Se core structure 30 in the third direction Z is the thickness of the Cd x Zn (1-x) Se core structure 30.
  • the ratio of the size of the core structure in the first direction X to the size of the core structure in the third direction Z is in the range of 6.5 to 15.75; and/or the ratio of the size of the core structure in the second direction Y to the size of the core structure in the third direction Z is in the range of 6.5 to 15.75.
  • the ratio of the size of the core structure in the first direction X to the size of the core structure in the third direction Z is 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5 or 15.75, etc., which is not limited here.
  • the ratio of the size of the core structure in the second direction Y to the size of the core structure in the third direction Z is 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5 or 15.75, etc., which is not limited here.
  • Figure 5 illustrates the structure of a core structure formed by the reaction of a CdSe quantum well 20 with a zinc halide.
  • the reaction between the CdSe quantum well 20 and the zinc halide is described later and is not detailed here.
  • the core structure has dimensions ranging from 7.8 nm to 12.6 nm in a first direction X, 7.8 nm to 12.6 nm in a second direction Y, and 0.8 nm to 1.2 nm in a third direction Z.
  • the size of the CdxZn (1-x) Se core structure 30 in the first direction X is 7.8 nm, 8 nm, 8.5 nm, 9 nm, 10 nm, 10.5 nm, 11 nm, 11.5 nm, 12 nm, or 12.6 nm, etc., which are not limited here.
  • the size of the CdxZn (1-x) Se core structure 30 in the second direction Y is 7.8 nm, 8 nm, 8.3 nm, 9.5 nm, 10.4 nm, 10.8 nm, 11.2 nm, 11.5 nm, 12 nm, or 12.6 nm, etc., which are not limited here.
  • the size of the CdxZn (1-x) Se core structure 30 in the third direction Z is 0.8 nm, 0.9 nm, 1 nm, 1.1 nm, or 1.2 nm, etc., which are not limited here.
  • the wavelength range of the fluorescence peak of the core structure can be adjusted.
  • the Cd x Zn (1-x) Se core structure 30 includes four selenium atomic layers 210 and five cadmium zinc atomic layers 310 , and the selenium atomic layers 210 and the cadmium zinc atomic layers 310 are alternately distributed along the third direction Z.
  • the atomic layer including selenium atoms 21 is a selenium atomic layer 210
  • the atomic layer including cadmium atoms 31 and zinc atoms 32 is a cadmium zinc atomic layer 310 .
  • cadmium atoms 31 in the CdSe quantum well 20 are replaced by zinc atoms 32, and the cadmium atomic layer 300 is formed into a cadmium zinc atomic layer 310.
  • the preparation method of forming the CdxZn (1-x) Se core structure 30 from the CdSe quantum well 20 is described in the subsequent content and is not described here in detail.
  • FIG6 shows an X-ray diffractomer (XRD) image of a CdSe quantum well 20.
  • the horizontal axis represents twice the incident angle of the X-ray, expressed as 2 ⁇ in degrees; the vertical axis represents the diffraction intensity in counts per second (c/s).
  • FIG6 shows that the peaks of 2 ⁇ for the CdSe quantum well 20 are located at 24° to 28°, 40° to 45°, and 47° to 51°, respectively. These three peaks of 2 ⁇ for the CdSe quantum well 20 indicate that the CdSe quantum well 20 has a zinc blende crystal structure.
  • Figure 7 is an X-ray diffraction image of the CdxZn (1-x) Se core structure 30.
  • the 2 ⁇ peaks of the CdxZn (1-x) Se core structure 30 are located at 24°-30°, 43°-46°, and 50°-54°, respectively.
  • the 2 ⁇ peaks of the CdxZn (1-x) Se core structure 30 are shifted to the right due to the presence of zinc atoms 32.
  • the three 2 ⁇ peaks of the CdxZn (1-x) Se core structure 30 indicate that the CdxZn (1-x) Se core structure 30 has a zinc blende crystal structure.
  • the shell structure 42 is made of an inorganic material.
  • the shell structure 42 can modify surface defects of the core structure, thereby passivating surface defects of the Cd x Zn (1-x) Se core structure 30 to enhance the luminescence performance of the quantum dot material 40.
  • the shell structure 42 can reduce the probability of electrons entering defects and being annihilated during transition, thereby enhancing the luminescence efficiency of the quantum dot material 40.
  • the quantum dot material 40 has a dimension in a first direction X, a dimension in a second direction Y, and a dimension in a third direction Z.
  • the ratio of the size of the quantum dot material in the first direction X to the size of the quantum dot material in the third direction Z is in the range of 2.8 to 6; and/or, the ratio of the size of the quantum dot material in the second direction Y to the size of the quantum dot material in the third direction Z is in the range of 2.8 to 6.
  • the ratio of the size of the quantum dot material in the first direction X to the size of the quantum dot material in the third direction Z is 2.8, 3, 3.5, 4, 4.5, 5, 5.5 or 6, etc., which is not limited here.
  • the ratio of the size of the quantum dot material in the second direction Y to the size of the quantum dot material in the third direction Z is 2.8, 3, 3.5, 4, 4.5, 5, 5.5 or 6, etc., which is not limited here.
  • the size of the quantum dot material 40 in the first direction X ranges from 10 nm to 15 nm
  • in the second direction Y ranges from 10 nm to 15 nm
  • in the third direction Z ranges from 2.5 nm to 3.5 nm.
  • the size of the quantum dot material 40 in the first direction X is 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, or 15 nm, etc., which is not limited here.
  • the size of the quantum dot material 40 in the second direction Y is 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, or 15 nm, etc., which is not limited here.
  • the size of the quantum dot material 40 in the third direction Z is 2.5 nm, 2.7 nm, 3.0 nm, 3.2 nm, or 3.5 nm, etc., which is not limited here.
  • the size distribution range of the quantum dot material 40 should be as small as possible.
  • the standard deviation of the thickness of the quantum dot material 40 is less than 2 nm
  • the standard deviation of the length of the quantum dot material 40 is less than 2 nm
  • the standard deviation of the width of the quantum dot material 40 is less than 2 nm.
  • the standard deviation is the square root of the arithmetic mean of the squared deviations from the mean.
  • a quantum dot material 40 having a size range of 10 nm to 15 nm in the first direction X, a size range of 10 nm to 15 nm in the second direction Y, and a size range of 2.5 nm to 3.5 nm in the third direction Z is formed, thereby providing the quantum dot material 40 emitting green light with a fluorescence peak wavelength range of 510 nm to 540 nm.
  • the quantum dot material further includes: a ligand group, the ligand group including: a group of at least one of oleic acid, 1-octanethiol, 2-ethyl-hexanethiol, 1-decanethiol, 1-dodecanethiol, tributylphosphine selenide and 1-octadecene selenide connected to the shell structure through a chemical bond.
  • a ligand group including: a group of at least one of oleic acid, 1-octanethiol, 2-ethyl-hexanethiol, 1-decanethiol, 1-dodecanethiol, tributylphosphine selenide and 1-octadecene selenide connected to the shell structure through a chemical bond.
  • the H in the carboxylic acid group (-COOH) in oleic acid is removed or chemically bonded to the shell structure to form a ligand, which can be called a carboxylic acid ligand;
  • the H in the thiol group (-SH) of 1-octanethiol is removed or chemically bonded to the shell structure to form a ligand, which can be called a thiol ligand.
  • the embodiments of the present disclosure further provide a method for preparing a quantum dot material containing a CdxZn (1-x) Se core structure 30. As shown in FIG5, FIG8 and FIG10, the method for preparing the quantum dot material includes steps S1 to S6.
  • the thickness of the CdSe quantum well 20 ranges from 0.8 nm to 1 nm.
  • the thickness of the CdSe quantum well 20 is 0.8 nm, 0.9 nm, or 1 nm, etc., which is not limited here.
  • the CdSe quantum well 20 includes: 4 layers of selenium atomic layers 210 and 5 layers of cadmium atomic layers 300, which are cross-distributed to form the CdSe quantum well 20.
  • the CdSe quantum well 20 can be expressed as 4.5 layers.
  • 0.5 refers to a single atomic layer due to the rich cations/anions on the upper and lower surfaces.
  • the upper and lower surfaces of the CdSe quantum well 20 are occupied by cadmium atoms 31.
  • the 0.5 in the CdSe quantum well 20 is a single atomic layer brought by the rich cations Cd2 + on the upper and lower surfaces of the CdSe quantum well 20.
  • the 4.5-layer CdSe quantum well 20 has a relatively stable structure and uniform morphology, making it suitable as a raw material for preparing a CdxZn (1-x) Se core structure 30 using an exchange reaction.
  • the fluorescence peak wavelength of the 4.5-layer CdSe quantum well 20 is in the range of 508nm to 513nm.
  • the wavelength of the fluorescence peak of the resulting CdxZn (1-x) Se core structure 30 is blue-shifted.
  • the concentration of the CdSe quantum wells 20 in the first solution ranges from 3 g/L to 6 g/L.
  • the concentration of the CdSe quantum wells 20 in the first solution can be 3 g/L, 4 g/L, 5 g/L, or 6 g/L, etc., without limitation.
  • CdSe quantum wells 20 with a concentration range of 3 g/L to 6 g/L have good dispersibility in the first organic solvent.
  • the first organic solvent includes at least one of 1-octadecene, paraffin oil, and olive oil.
  • 1- octadecene has a molecular formula of C18H36 and is a colorless liquid that is soluble in hot propanol and insoluble in water.
  • Paraffin oil is a mineral oil, a colorless and odorless mixture obtained from crude oil fractionation. Its primary component is hydrocarbons. Paraffin oil is a mixture of several higher alkanes, primarily including n- docosane ( C22H46 ) and n- octacosane ( C28H58 ), containing approximately 85% carbon and over 14% hydrogen.
  • Olive oil is directly cold-pressed from fresh olive fruit.
  • the ratio of the mass of zinc halide to the mass of CdSe quantum well 20 ranges from 3 to 32.
  • the ratio of the mass of zinc halide to the mass of CdSe quantum well 20 is 3, 5, 8, 9, 10, 12, 16, 18, 22, 25, 28, 30, 31, or 32, etc., and is not limited thereto.
  • the molar concentration of zinc atoms 32 in the second solution ranges from 0.05 mol/L to 0.2 mol/L.
  • the molar concentration of zinc atoms 32 can be 0.05 mol/L, 0.1 mol/L, 0.15 mol/L, or 0.2 mol/L, etc., without limitation.
  • the molar concentration of zinc atoms 32 in the range of 0.05 mol/L to 0.2 mol/L can ensure sufficient reaction between zinc atoms 32 and CdSe quantum wells 20.
  • the zinc halide includes zinc iodide, zinc chloride, or zinc bromide, etc., which are not limited here.
  • the second solution is stirred under vacuum conditions at a temperature ranging from 80° C. to 100° C. Since zinc halide is easily hygroscopic and oxidizable, the second solution is treated under vacuum to remove water and oxygen in the reaction system to prevent water and oxygen from affecting the reaction.
  • the second solution is stirred at a temperature ranging from 80° C. to 100° C. under vacuum conditions for about 1 hour to allow the zinc halide to efficiently release zinc ions and ensure effective removal of water and oxygen in the reaction system.
  • the ratio of the volume of the first organic solvent to the volume of the phosphorus source ligand is in a range of 2.5 to 30.
  • the ratio of the volume of the first organic solvent to the volume of the phosphorus source ligand is 2.5, 3, 5, 8, 10, 12, 15, 18, 22, 23, 26, 28, 29, or 30, etc., and is not limited thereto.
  • the ratio of the volume of the first organic solvent to the volume of the fatty amine ranges from 5 to 150.
  • the ratio of the volume of the first organic solvent to the volume of the fatty amine is 5, 10, 15, 22, 36, 45, 55, 70, 80, 95, 110, 120, 125, 130, 145, or 150, etc., and is not limited thereto.
  • the inert gas includes at least one of nitrogen, helium, and argon.
  • the inert gas can be nitrogen, which is relatively low in cost. Since the second solution is treated under vacuum conditions in step S2, the addition of the inert gas in this step restores the pressure of the reaction system to normal pressure, which facilitates the subsequent smooth addition of the phosphorus source ligand and the fatty amine.
  • the phosphorus source ligand includes at least one of tri-n-octylphosphine, tributylphosphine, and trioctylphosphine oxide.
  • Tri-n - octylphosphine is a colorless liquid with a molecular formula of C24H5P ;
  • tributylphosphine is a colorless, transparent liquid with a chemical formula of C12H5P ;
  • trioctylphosphine oxide has a molecular formula of C24H5OP .
  • the phosphorus source ligand is weakly alkaline and has good binding affinity with the cadmium atoms 31 on the surface of the CdSe quantum well 20, thereby helping the cadmium atoms 31 to achieve solvation, that is, facilitating their detachment from the CdSe quantum well 20 and entry into the solvent.
  • the fatty amine includes at least one of oleylamine and octylamine.
  • Oleylamine has a molecular formula of C 18 H 37 N and is a colorless to pale yellow liquid.
  • Octylamine has a molecular formula of C 8 H 19 N.
  • the fatty amine has a weak binding ability with the zinc atoms 32 and can effectively release the zinc ions, thereby replacing the cadmium atoms 31 in the CdSe quantum well 20 .
  • fatty amine is a typical weak ligand of nanocrystals.
  • Fatty amine forms a complex with CdSe quantum well 20, which helps to maintain the stability of the crystal surface and control the reaction rate to ensure that the width of the reaction area is smaller than the size of the crystal, thereby effectively avoiding the failure of the reaction process caused by the decomposition of CdSe quantum well 20.
  • the third solution is stirred under an inert gas atmosphere at a temperature range of 200°C to 280°C.
  • the temperature is 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, or 280°C, etc., without limitation.
  • the temperature fluctuates by no more than 5°C to maintain reaction stability.
  • a temperature range of 200°C to 280°C can ensure smooth reaction.
  • the CdSe quantum well 20 reacts with the zinc halide to form a CdxZn (1-x) Se core structure 30, which is dispersed in the fourth solution.
  • cadmium atoms 31 break away from the CdSe quantum well 20 and enter the solvent to form spacers.
  • the fatty amine is oleic acid
  • due to the weak binding ability of oleylamine with zinc atoms 32 zinc ions are effectively released.
  • the zinc ions enter the crystal lattice to form zinc atoms 32, which then occupy the position of cadmium atoms 31, resulting in the CdxZn (1-x) Se core structure 30.
  • zinc atoms 32 and cadmium atoms 31 undergo replacement, as shown in the following chemical reaction formula.
  • This step can produce Cd x Zn (1-x) Se core structures 30 with different values of x. Furthermore, as the reaction time increases, the Cd x Zn (1-x) Se core structure 30 contains less cadmium atoms 31 and more zinc atoms 32. In other words, as the reaction time increases, the wavelength of the fluorescence peak of the Cd x Zn (1-x) Se core structure 30 gradually shifts to the blue.
  • the reaction is monitored in real time by sampling the fourth solution, and the reaction progress is determined by absorption spectroscopy.
  • the fluorescence peak of the 4.5-layer CdSe quantum well 20 has a wavelength range of 508nm to 513nm. As the reaction proceeds, the wavelength of the fluorescence peak of the reaction product gradually shifts to the blue light region. When the wavelength of the fluorescence peak of the reaction product reaches 440nm to 510nm, the reaction is promptly terminated by cooling the reaction vessel in a water bath.
  • the Cd x Zn (1-x) Se core structure 30 is insoluble in the first polar solvent.
  • the first polar solvent can cause the Cd x Zn (1-x) Se core structure 30 to precipitate as a precipitate.
  • the first polar solvent is, for example, ethanol.
  • the precipitate of the Cd x Zn (1-x) Se core structure 30 is centrifuged and washed multiple times to obtain the purified Cd x Zn (1-x) Se core structure 30 .
  • the CdxZn (1-x) Se core structure 30 is prepared through the above steps S1 to S5.
  • the doping amount of zinc atoms 32 can be regulated by controlling the reaction time, thereby adjusting the wavelength of the fluorescence peak of the CdxZn (1-x) Se core structure 30.
  • the shell structure 42 encapsulates the core structure to obtain a quantum dot material 40, wherein the wavelength range of the fluorescence peak of the quantum dot material 40 is 510 nm to 540 nm.
  • the method for preparing the shell structure includes steps: S61 to S65 .
  • a precursor is defined as a prototype of the target product, i.e., a precursor product that can be achieved after certain steps. In other words, a precursor is a form of existence before the target product is obtained.
  • Anion precursors are used to provide anions for the shell structure 42 material in the quantum dot material 40.
  • the anion precursor includes at least one of 1-octanethiol, 2-ethylhexylthiol, 1-decanethiol, 1-dodecanethiol, tributylphosphine selenide, and 1-octadecene selenide.
  • the ratio of the volume of the anion precursor to the volume of the second organic solvent is 2 ⁇ 10 ⁇ 3 , 10 ⁇ 10 ⁇ 3 , 15 ⁇ 10 ⁇ 3 , 18 ⁇ 10 ⁇ 3 , 20 ⁇ 10 ⁇ 3 , 23 ⁇ 10 ⁇ 3 , 26 ⁇ 10 ⁇ 3 or 28 ⁇ 10 ⁇ 3 , etc., which is not limited here.
  • the second organic solvent includes at least one of 1-octadecene, paraffin oil, and olive oil.
  • the first organic solvent and the second organic solvent may be the same.
  • the amount of the first non-polar solvent used is such that the ratio of the volume of the first organic solvent in step S1 to the volume of the first non-polar solvent in this step is in a range of 2.5 to 15.
  • the ratio of the volume of the first organic solvent to the volume of the first non-polar solvent is 2.5, 3, 3.5, 5, 6.5, 7, 8.5, 10, 12, 13, 14, or 15, etc., and is not limited thereto.
  • the ratio of the mass of the CdSe quantum well 20 to the volume of the first non-polar solvent in step S1 ranges from 15 g/L to 30 g/L.
  • the ratio of the mass of the CdSe quantum well 20 to the volume of the first non-polar solvent is 15 g/L, 20 g/L, 25 g/L or 30 g/L, etc., which is not limited here.
  • the first non-polar solvent includes at least one of n-hexane, octane, and dodecane.
  • the Cd x Zn (1-x) Se core structure 30 has good dispersibility in the first non-polar solvent.
  • the ratio of the volume of the third organic solvent to the volume of the sixth solution ranges from 2.5 to 15.
  • the ratio of the volume of the third organic solvent to the volume of the sixth solution is 2.5, 3, 3.5, 5, 6.5, 7, 8.5, 10, 12, 13, 14 or 15, etc., which is not limited here.
  • the ratio of the volume of the third organic solvent to the volume of oleic acid ranges from 2.5 to 30.
  • the ratio of the volume of the third organic solvent to the volume of oleic acid is 2.5, 5, 8, 9, 12, 15, 17, 18, 20, 22, 24, 26, 28 or 30, etc., which is not limited here.
  • the cation in the cationic precursor includes at least one of Zn and Cd.
  • the cationic precursor includes at least one of zinc acetate, zinc oleate, zinc stearate, zinc laurate, cadmium acetate, and cadmium oleate.
  • zinc atom 32 and sulfur atom 41 form ZnS, forming a shell structure 42.
  • the ratio of the molar number of cations in the cationic precursor in the seventh solution to the molar number of anions in the anionic precursor in the fifth solution is in the range of 1:4 to 1:2.
  • the ratio of the molar number of cations in the cationic precursor in the seventh solution to the molar number of anions in the anionic precursor in the fifth solution is 1:4, 1:3, or 1:2, etc., without limitation.
  • the third organic solvent includes at least one of 1-octadecene, paraffin oil, and olive oil.
  • the first organic solvent, the second organic solvent, and the third organic solvent are all 1-octadecene.
  • the seventh solution is stirred under vacuum conditions at a temperature range of 90° C. to 100° C. for about 1 hour to effectively remove water and oxygen, thereby preventing the water and oxygen from causing oxidation of the cationic precursor.
  • a cationic oleic acid solution By stirring the seventh solution under vacuum conditions in a temperature range of 90°C to 100°C, a cationic oleic acid solution can be formed.
  • the cationic precursor is zinc acetate.
  • zinc oleate is obtained in the seventh solution.
  • Zinc oleate provides a Zn source for the material of the shell structure 42, which is conducive to the formation of the shell structure 42.
  • the fifth solution is added to the seventh solution, and the reaction time ranges from 30 minutes to 90 minutes.
  • the reaction temperature is 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 310°C, 315°C, or 320°C, etc., and is not limited thereto. Setting a temperature range of 280°C to 320°C can ensure smooth progress of the reaction.
  • reaction time is 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 58 minutes, 60 minutes, 62 minutes, 65 minutes, 70 minutes, 75 minutes, 80 minutes, 85 minutes or 90 minutes, etc., and is not limited thereto.
  • the inert gas includes at least one of nitrogen, helium, and argon. Since the seventh solution is treated under vacuum conditions in step S63, the inert gas is added in step S64 to restore the pressure of the reaction system to normal pressure, which is conducive to the smooth addition of the fifth solution.
  • FIG. 10 is a structural diagram showing a ZnS shell structure 42 formed by the reaction of 1-octanethiol and zinc acetate.
  • the ZnS shell structure 42 encapsulates the Cd x Zn (1-x) Se core structure 30 to form a quantum dot material 40 .
  • the second polar solvent includes at least one of ethanol, methanol, acetonitrile, and acetone.
  • Quantum dot material 40 is insoluble in the second polar solvent, and the second polar solvent can cause quantum dot material 40 to precipitate.
  • the quantum dot material precipitate 40 is then centrifuged and washed multiple times to obtain purified quantum dot material 40.
  • the precipitate of the quantum dot material 40 is dispersed in a second non-polar solvent to preserve the quantum dot material 40
  • the second non-polar solvent in which the quantum dot material 40 is dispersed can be used to prepare the light-emitting layer 132 of the light-emitting device 130.
  • the second non-polar solvent includes at least one of n-hexane, octane, and dodecane.
  • the quantum dot material 40 is in a quantum well structure.
  • the quantum dot material 40 with a quantum well structure is subject to the quantum confinement effect in one-dimensional longitudinal direction.
  • the quantum dot material 40 is obtained by wrapping the surface of a CdxZn (1-x) Se core structure 30 having a fluorescence peak wavelength range of 440nm to 510nm with an inorganic protective shell layer.
  • the size of the quantum dot material 40 in one-dimensional longitudinal direction becomes larger, and the exciton recombination emission wavelength of the quantum dot material 40 will be red-shifted, thereby obtaining a quantum dot material 40 emitting green light with a fluorescence peak wavelength range of 510nm to 540nm, which is applied to provide a light-emitting device 130 emitting green light.
  • a shell structure 42 is coated on the surface of the CdxZn (1-x) Se core structure 30 through steps S61 to S65, forming a quantum dot material 40 having a fluorescence peak wavelength range of 510 nm to 540 nm. Furthermore, the emission wavelength of the quantum dot material 40 is tunable, making the emission wavelength of the quantum dot material 40 independent of the number of crystal layers.
  • the method for preparing quantum dot materials in steps S1 to S6 above the following example is provided to prepare CdxZn (1-x) Se/ZnS quantum dot material 40.
  • the method for preparing CdxZn (1-x) Se/ZnS quantum dot material includes steps R1 to R10.
  • Tri-n-octylphosphine is used as a phosphorus source ligand.
  • the phosphorus source ligand is weakly alkaline and has good binding ability with the cadmium atoms 31 on the surface of the CdSe quantum well 20. It can help the cadmium atoms 31 to be solvated, that is, it helps the cadmium atoms 31 to escape from the CdSe quantum well 20 and enter the solvent.
  • the CdSe quantum well 20 reacts with zinc iodide to obtain a Cd x Zn (1-x) Se core structure 30 .
  • Figure 12 shows the photoluminescence spectra of the CdxZn (1-x) Se core structure 30 obtained at different reaction times.
  • the abscissa represents the emission wavelength in nm
  • the ordinate represents the fluorescence intensity in au (Absorbance Unit).
  • the wavelength of the fluorescence peak of the CdxZn (1-x) Se core structure 30 gradually blue-shifts.
  • the wavelength of the fluorescence peak of the CdxZn (1-x) Se core structure 30 is approximately 470 nm.
  • Figure 13 shows an X-ray diffraction image of a CdSe quantum well 20 reacting with zinc iodide for 40 minutes.
  • the abscissa represents size in nm, and the ordinate represents the number of cells.
  • the abscissa represents the length or width of the CdSe quantum well 20 and the length or width of the CdxZn (1-x) Se core structure 30.
  • the size of the CdSe quantum well 20 ranges from 9 nm to 14 nm, primarily ranging from 10.5 nm to 12.3 nm.
  • the size of the CdxZn (1-x) Se core structure 30 ranges from 6 nm to 14 nm, primarily ranging from 8.8 nm to 11.6 nm. Therefore, compared to the size of the CdSe quantum well 20, the size of the CdxZn (1 -x) Se core structure 30 is relatively small.
  • Figure 14 shows the mass content of cadmium atoms 31 (denoted as Cd ) and zinc atoms 32 (denoted as Zn) in the resulting CdxZn (1-x) Se core structure 30 during the reaction between the CdSe quantum well 20 and zinc iodide as a function of reaction time.
  • This figure also known as an inductively coupled plasma emission spectrometer, shows the reaction time in minutes on the abscissa, and the mass content percentage on the ordinate.
  • the mass content of cadmium atoms 31 is the ratio of the mass of cadmium atoms 31 to the sum of the mass of cadmium atoms 31 and the mass of zinc atoms 32; the mass content of zinc atoms 32 is the ratio of the mass of zinc atoms 32 to the sum of the mass of cadmium atoms 31 and the mass of zinc atoms 32.
  • Figure 14 shows that as the reaction time increases, the mass content of zinc atoms 32 in the CdxZn (1-x) Se core structure 30 gradually increases, while the mass content of cadmium atoms 31 gradually decreases.
  • the fluorescence peak wavelength of the CdxZn (1-x) Se core structure 30 can be in the range of 440nm to 510nm.
  • the CdxZn (1-x) Se core structure 30 can be used to form a quantum dot material 40 emitting green light.
  • the Cd x Zn (1-x) Se core structure 30 has good dispersibility in hexane. Therefore, hexane can be used to preserve the Cd x Zn (1-x) Se core structure 30.
  • Zinc acetate is a cationic precursor used to provide a zinc source.
  • Zinc acetate is mixed with oleic acid to obtain zinc oleate, and the zinc ions in zinc oleate are used to form the ZnS shell structure42.
  • the reaction time ranges from 30 minutes to 90 minutes.
  • the reaction temperature is set to 305° C. to ensure that the carbon-sulfur chemical bond in 1-octanethiol can be broken, thereby providing sulfur atoms 41 for forming the ZnS shell structure 42 .
  • Figure 16 shows the photoluminescence spectra of quantum dot material 40 obtained with different reaction times.
  • the horizontal axis represents the emission wavelength in nm, and the vertical axis represents the fluorescence intensity in a.u.
  • the wavelength of the fluorescence peak of quantum dot material 40 gradually red-shifts. Therefore, for reaction times ranging from 30 to 90 minutes, quantum dot material 40 with a fluorescence peak wavelength range of 510 to 540 nm can be obtained, which can be used to emit green light.
  • the quantum dot material 40 is a CdxZn (1-x) Se/ZnS quantum dot material 40, which has a quantum well structure.
  • the fluorescence quantum yield of the quantum dot material 40 ranges from 60% to 90%, i.e., the fluorescence quantum yield of the quantum dot material 40 is greater than or equal to 60% and less than or equal to 90%. For example, the fluorescence quantum yield of the quantum dot material 40 is greater than 80%.
  • FIG17 is a scanning electron microscope image of the CdxZn (1-x) Se/ZnS quantum dot material 40.
  • the CdxZn (1-x) Se/ZnS quantum dot material 40 has a relatively uniform size, and the length and width of the CdxZn (1-x) Se/ZnS quantum dot material 40 range from 10 nm to 15 nm.
  • Oleic acid and at least one of 1-octanethiol, 2-ethyl-hexylthiol, 1-decylthiol, 1-dodecanethiol, tributylphosphine selenide and 1-octadecene selenide are present in the solution system of the quantum dot material 40.
  • the precipitate of the CdxZn (1-x) Se/ZnS quantum dot material 40 is then dispersed in n-octane to preserve the CdxZn (1-x) Se/ZnS quantum dot material 40, and the n-octane solution in which the CdxZn (1-x) Se/ZnS quantum dot material 40 is dispersed can be used to prepare the light-emitting layer 132 of the light-emitting device 130.
  • Tri-n-octylphosphine and other tertiary phosphine organic compounds serve as phosphorus source ligands. These phosphorus source ligands have good binding ability with cadmium atoms 31 on the surface of CdSe quantum well 20, helping cadmium atoms 31 to achieve solvation, that is, helping cadmium atoms 31 to escape from CdSe quantum well 20 and enter the solvent. In this reaction system, tertiary phosphine organic compounds can ensure the smooth progress of the reaction.
  • a light-emitting device 130 includes a stacked first electrode 131, a hole injection layer 134, a hole transport layer 135, a light-emitting layer 132, an electron transport layer 136, and a second electrode 133.
  • the material of the light-emitting layer 132 includes the CdxZn (1-x) Se/ZnS quantum dot material 40 provided in any of the above embodiments.
  • the light-emitting device 130 is configured to emit green light.
  • the material of the hole injection layer 134 may include poly (3,4-ethylenedioxythiophene), polystyrene sulfonic acid, salt PEDOT:PSS4083 (poly (3,4-ethylenedioxythiophene/polystyrene sulfonate)) or other compounds suitable for hole injection, which is not limited here.
  • the material of the hole transport layer 135 may include poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) or polyvinylcarbazole (PVK), etc., which are not limited here.
  • TFB poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)
  • PVK polyvinylcarbazole
  • the hole injection layer 134 , the hole transport layer 135 and the electron transport layer 136 may improve the carrier transport performance of the light emitting device 130 , thereby improving the light emitting performance of the light emitting device 130 .

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Abstract

一种量子点材料,所述量子点材料为核壳结构,其中,核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15,所述量子点材料的荧光峰的波长范围为510nm~540nm。

Description

量子点材料及其制备方法、发光器件、显示面板
本申请要求于2024年3月27日提交的、申请号为PCT/CN2024/084140的国际专利申请的优先权,其全部内容通过引用结合在本申请中。
技术领域
本公开涉及材料合成技术领域,尤其涉及一种量子点材料及其制备方法、发光器件、显示面板。
背景技术
胶体半导体片状纳米晶体的形状类似长方体,为纳米尺度。尺寸特点为:厚度尺寸范围为0.3nm~10nm,长度尺寸范围为2nm~100nm,宽度尺寸范围为2nm~100nm。胶体半导体片状纳米晶体的材料包括II-VI族元素,其中,II族元素包括锌(Zn)和镉(Cd),VI族元素包括硫(S)、硒(Se)和碲(Te)。
发明内容
一方面,提供一种量子点材料,所述量子点材料为核壳结构,其中,核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15,所述量子点材料的荧光峰的波长范围为510nm~540nm。
在一些实施例中,所述量子点材料具有:第一方向上的尺寸、第二方向上的尺寸和第三方向上的尺寸,所述第一方向、所述第二方向和所述第三方向相垂直。其中,所述量子点材料在所述第一方向上的尺寸与所述量子点材料在所述第三方向上的尺寸的比值范围为2.8~6;和/或,所述量子点材料在所述第二方向上的尺寸与所述量子点材料在所述第三方向上的尺寸的比值范围为2.8~6。
在一些实施例中,所述量子点材料在第一方向上的尺寸范围为10nm~15nm,在第二方向上的尺寸范围为10nm~15nm,在第三方向上的尺寸范围为2.5nm~3.5nm。
在一些实施例中,所述核结构的荧光峰的波长范围为440nm~510nm。
在一些实施例中,所述核结构具有:第一方向上的尺寸、第二方向上的尺寸和第三方向上的尺寸。其中,所述核结构在所述第一方向上的尺寸与所述核结构在所述第三方向上的尺寸的比值的范围为6.5~15.75;和/或,所述核结构在所述第二方向上的尺寸与所述核结构在所述第三方向上的尺寸的比值的范围为6.5~15.75。
在一些实施例中,所述核结构在第一方向上的尺寸范围为7.8nm~12.6nm,在第二方向上的尺寸范围为7.8nm~12.6nm,在第三方向上的尺寸范围为0.8nm~1.2nm;其中,所述第一方向、所述第二方向和所述第三方向相垂直。
在一些实施例中,所述核结构包括:4层硒原子层和5层镉锌原子层,硒原子层和镉锌原子层沿第三方向交替分布。
在一些实施例中,所述核结构为闪锌矿晶体结构。
在一些实施例中,在X射线衍射成像图中,所述核结构的X射线的入射角度的两倍的峰值有三个,分别位于:24°~30°、43°~46°和50°~54°。
在一些实施例中,所述量子点材料的荧光峰的波长随着x的减小而变短。
在一些实施例中,壳结构的材料包括:ZnS、ZnSe、ZnSeS和CdS中的至少一种。
在一些实施例中,壳结构包裹所述核结构。
在一些实施例中,所述量子点材料呈量子阱结构。
在一些实施例中,所述量子点材料还包括:配体基团,所述配体基团包括:油酸、1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一种与壳结构通过化学键连接后的基团。
另一方面,提供一种量子点材料的制备方法,该方法包括:将CdSe量子阱分散在第一有机溶剂中,得到第一溶液;向所述第一溶液中加入卤化锌,得到第二溶液;向所述第二溶液中加入磷源配体和脂肪胺,得到第三溶液;搅拌所述第三溶液,反应后得到第四溶液;向所述第四溶液中加入第一极性溶剂,得到所述量子点材料的核结构,所述核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15;形成壳结构,所述壳结构包裹所述核结构,得到量子点材料,所述量子点材料的荧光峰的波长范围为510nm~540nm。
在一些实施例中,在所述第一溶液中,所述CdSe量子阱包括:4层硒原子层和5层镉原子层,硒原子层和镉原子层交替分布;在所述第二溶液中,所述卤化锌的质量与所述CdSe量子阱的质量的比值范围为3~32;且在温度范围为80℃~100℃的真空条件下搅拌所述第二溶液;在所述第三溶液中,所述第一有机溶剂的体积与所述磷源配体的体积的比值范围为2.5~30,所述第一有机溶剂的体积与所述脂肪胺的体积的比值范围为5~150;所述搅拌所述第三溶液,为在惰性气体氛围且温度范围为200℃~280℃的条件下进行。
在一些实施例中,所述卤化锌包括:碘化锌、氯化锌和溴化锌中的至少一种。
在一些实施例中,所述磷源配体包括:三正辛基膦、三丁基膦和三辛基氧化膦中的至少一种;和/或,所述脂肪胺包括:油胺和辛胺中的至少一种。
在一些实施例中,所述第一有机溶剂包括:1-十八烯、石蜡油和橄榄油中的至少一种。
在一些实施例中,所述第一极性溶剂包括:乙醇、甲醇、乙腈和丙酮中的至少一种。
在一些实施例中,所述形成壳结构包括:将阴离子前驱体分散在第二有机溶剂中,得到第五溶液;其中,所述阴离子前驱体的体积与所述第二有机溶剂的体积的比值范围为2×10-3~28×10-3,所述阴离子前驱体中的阴离子包括S和Se中的至少一种;将得到的所述核结构CdxZn(1-x)Se分散在第一非极性溶剂中,得到第六溶液。
将所述第六溶液加入第三有机溶剂中,并加入阳离子前驱体和油酸,得到第七溶液;并在温度范围为90℃~100℃的真空条件下搅拌所述第七溶液;其中,所述第三有机溶剂的体积与所述第六溶液的体积的比值范围为2.5~15;所述第三有机溶剂的体积与所述油酸的体积的比值范围为2.5~30;所述阳离子前驱体中的阳离子包括Zn和Cd中的至少一种。
在惰性气体氛围且温度范围为280℃~320℃条件下,向所述第七溶液中加入所述第五溶液,反应后得到第八溶液;向所述第八溶液中加入第二极性溶剂,得到所述量子点材料,所述量子点材料的荧光峰的波长范围为510nm~540nm。
在一些实施例中,所述阴离子前驱体包括:1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一种。
在一些实施例中,所述阳离子前驱体包括:乙酸锌、油酸锌、硬脂酸锌、月桂酸锌、乙酸镉和油酸镉中的至少一种。
在一些实施例中,所述第一非极性溶剂包括:正己烷、辛烷和十二烷中的至少一种。
在一些实施例中,所述在惰性气体氛围且温度范围280℃~320℃的条件下,向所述第七溶液中加入所述第五溶液,反应时长范围为30分钟~90分钟。
又一方面,提供一种发光器件,该发光器件包括:相对设置的第一电极和第二电极,以及位于所述第一电极和所述第二电极之间的发光层;其中,所述发光层包括:如上任一实施例所述的量子点材料。
又一方面,一种显示面板,该显示面板包括:如上任一实施例所述的发光器件和像素驱动电路;像素驱动电路用于驱动所述发光器件发光。
附图说明
为了更清楚地说明本公开中的技术方案,下面将对本公开一些实施例中所需要使用的附图作简单地介绍,显而易见地,下面描述中的附图仅仅是本公开的一些实施例的附图,对于本领域普通技术人员来讲,还可以根据这些附图获得其他的附图。此外,以下描述中的附图可以视作示意图,并非对本公开实施例所涉及的产品的实际尺寸、方法的实际流程等的限制。
图1为根据本公开一些实施例的显示装置的结构图;
图2为根据本公开一些实施例的显示面板的结构图;
图3为根据本公开一些实施例的显示面板的另一种结构图;
图4为根据本公开一些实施例的发光器件的结构图;
图5为根据本公开一些实施例的CdSe量子阱与卤化锌反应形成核结构的结构图;
图6为根据本公开一些实施例的CdSe量子阱的X射线衍射成像图;
图7为根据本公开一些实施例的CdxZn(1-x)Se核结构的X射线衍射成像图;
图8为根据本公开一些实施例的CdxZn(1-x)Se核结构的制备方法的流程图;
图9为根据本公开一些实施例的壳结构的制备方法的流程图;
图10为根据本公开一些实施例的1-辛硫醇和乙酸锌反应形成ZnS壳结构的结构图;
图11为根据本公开一些实施例的CdxZn(1-x)Se/ZnS量子点材料的制备方法的流程图;
图12为根据本公开一些实施例的不同反应时长得到的CdxZn(1-x)Se核结构的光致发光光谱图;
图13为根据本公开一些实施例的CdSe量子阱与碘化锌反应40分钟的X射线衍射成像图;
图14为根据本公开一些实施例的形成的CdxZn(1-x)Se核结构中的镉原子的质量含量和锌原子的质量含量随反应时长的变化图;
图15为根据本公开一些实施例的CdxZn(1-x)Se核结构的扫描电镜图;
图16为根据本公开一些实施例的不同反应时长得到的量子点材料的光致发光的光谱图;
图17为根据本公开一些实施例的CdxZn(1-x)Se/ZnS量子点材料的扫描电镜图;
图18为根据本公开一些实施例的发光器件的另一种结构图;
图19为根据本公开一些实施例的发光器件的电流效率曲线图;
图20为根据本公开一些实施例的发光器件的外量子效率曲线图。
具体实施方式
下面将结合附图,对本公开一些实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅仅是本公开一部分实施例,而不是全部的实施例。基于本公开所提供的实施例,本领域普通技术人员所获得的所有其他实施例,都属于本公开保护的范围。
除非上下文另有要求,否则,在整个说明书和权利要求书中,术语“包括(comprise)”及其其他形式例如第三人称单数形式“包括(comprises)”和现在分词形式“包括(comprising)”被解释为开放、包含的意思,即为“包含,但不限于”。在说明书的描述中,术语“一个实施例(one embodiment)”、“一些实施例(some embodiments)”、“示例性实施例(exemplary embodiments)”、“示例(example)”、“特定示例(specific example)”或“一些示例(some examples)”等旨在表明与该实施例或示例相关的特定特征、结构、材料或特性包括在本公开的至少一个实施例或示例中。上述术语的示意性表示不一定是指同一实施例或示例。此外,所述的特定特征、结构、材料或特点可以以任何适当方式包括在任何一个或多个实施例或示例中。
以下,术语“第一”、“第二”仅用于描述目的,而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此,限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本公开实施例的描述中,除非另有说明,“多个”的含义是两个或两个以上。
“A、B和C中的至少一个”与“A、B或C中的至少一个”具有相同含义,均包括以下A、B和C的组合:仅A,仅B,仅C,A和B的组合,A和C的组合,B和C的组合,及A、B和C的组合。
“A和/或B”,包括以下三种组合:仅A,仅B,及A和B的组合。
如本文所使用的那样,“约”、“大致”或“近似”包括所阐述的值以及处于特定值的可接受偏差范围内的平均值,其中所述可接受偏差范围如由本领域普通技术人员考虑到正在讨论的测量以及与特定量的测量相关的误差(即,测量系统的局限性)所确定。
如本文所使用的那样,“平行”、“垂直”、“相等”包括所阐述的情况以及与所阐述的情况相近似的情况,该相近似的情况的范围处于可接受偏差范围内,其中所述可接受偏差范围如由本领域普通技术人员考虑到正在讨论的测量以及与特定量的测量相关的误差(即,测量系统的局限性)所确定。例如,“平行”包括绝对平行和近似平行,其中近似平行的可接受偏差范围例如可以是5°以内偏差;“垂直”包括绝对垂直和近似垂直,其中近似垂直的可接受偏差范围例如也可以是5°以内偏差。“相等”包括绝对相等和近似相等,其中近似相等的可接受偏差范围内例如可以是相等的两者之间的差值小于或等于其中任一者的5%。
应当理解的是,当层或元件被称为在另一层或基板上时,可以是该层或元件直接在另一层或基板上,或者也可以是该层或元件与另一层或基板之间存在中间层。
本文参照作为理想化示例性附图的剖视图和/或平面图描述了示例性实施方式。在附图中,为了清楚,放大了层的厚度和区域的面积。因此,可设想到由于例如制造技术和/或公差引起的相对于附图的形状的变动。因此,示例性实施方式不应解释为局限于本文示出的区域的形状,而是包括因例如制造而引起的形状偏差。例如,示为矩形的蚀刻区域通常将具有弯曲的特征。因此,附图中所示的区域本质上是示意性的,且它们的形状并非旨在示出设备的区域的实际形状,并且并非旨在限制示例性实施方式的范围。
如图1所示,本公开的一些实施例提供一种显示装置1000。本公开的实施例所提供的显示装置1000可以是显示不论运动(例如,视频)还是固定(例如,静止图像)的且不论文字还是图像的任何装置。更明确地说,预期所述实施例可实施在多种电子装置中或与多种电子装置关联,所述多种电子装置例如(但不限于)移动电话、无线装置、个人数据助理(Personal Digital Assistant,PDA)、手持式或便携式计算机、GPS接收器/导航器、相机、MP4视频播放器、摄像机、游戏控制台、手表、时钟、计算器、电视监视器、平板显示器、计算机监视器、汽车显示器(例如,里程表显示器等)、导航仪、座舱控制器和/或显示器、相机视图的显示器(例如,车辆中后视相机的显示器)、电子相片、电子广告牌或指示牌、投影仪、建筑结构、包装和美学结构(例如,对于一件珠宝的图像的显示器)等。
具体地,如图1所示,本公开实施例中以显示装置1000为手机进行示例性说明。
如图1和图2所示,显示装置1000包括显示面板100,显示面板100包括显示区AA和位于显示区AA至少一侧的周边区BB,其中,显示区AA设置有多个子像素10和多条信号线,多个子像素10按照指定规则排列设置于显示区AA内。其中,子像素10是显示面板100内进行画面显示的最小单元,每个子像素10可以显示单一的颜色,例如红色、绿色或蓝色,通过调节不同子像素10的亮度,使得颜色叠加可以实现多种颜色的显示。
示例性地,如图3所示,以该显示面板100为QLED(Quantum Dot Light Emitting Diodes,量子点发光二极管)显示面板为例,显示面板100包括依次层叠设置的衬底11、阵列基板12和发光器件层13,其中,阵列基板12中设置有多个像素驱动电路120,多个像素驱动电路120可以形成于显示面板100的显示区AA。发光器件层13包括多个发光器件130,像素驱动电路120用于驱动发光器件130发光。
在一些实施例中,如图4所示,发光器件130包括依次层叠设置的第一电极131、发光层132和第二电极133。
示例性的,第一电极131为阳极和阴极中的一者,第二电极133为阴极和阳极中的另一者。例如,第一电极131为阳极,第二电极133为阴极。发光器件130的发光原理为通过阳极和阴极连接的电路,利用阳极向发光层132注入空穴,阴极向发光层132注入电子,所形成的电子和空穴在发光层132中形成激子,激子通过辐射跃迁回到基态,发出光子。
在一些实施例中,发光层132包括量子点材料,例如,量子阱结构的量子点材料也称为纳米片,由于其形似片状,因而量子阱结构的量子点材料在一维纵向上受到量子限域效应。此处的一维纵向是指量子点材料的厚度所在的方向。
需要说明的是,量子阱结构的量子点材料属于一种胶体半导体纳米晶。胶体半导体纳米晶是由湿化学法合成而得的纳米半导体晶体,其尺寸、组分、形貌和结构容易调控,经过多年的发展已经可以实现球状(量子点)、棒状(纳米棒)或片状(纳米片)的可控制备。
当一个能量高于半导体能隙的光子被胶体半导体纳米晶吸收后,半导体的电子从价带(valence band)激发到导带(conduction band),并在价带上产生一个带正电荷的空穴,被激发的相互作用的电子-空穴对称为激子(exciton)。半导体材料中电子围绕空穴运动存在一个运动半径,称之为波尔半径。当半导体材料三维中任意一个尺寸等于或小于该材料的波尔半径时,激子的活动受到粒子尺寸的限制,能级由连续分布变为离散分布,这就是量子限域效应。
也就是说,量子阱结构的量子点材料作为片状的纳米晶,量子点材料在一维纵向上的激子的活动受到粒子尺寸的限制,能级由连续分布变为离散分布。量子点材料在一维纵向上的尺寸对量子点材料的荧光峰的波长具有重要影响。通常情况下,量子点材料在一维纵向上的尺寸越大,量子点材料的荧光峰的波长会发生红移。荧光峰是指在带状的荧光光谱中的一个或数个峰。荧光峰所在的波长称为发射波长。
量子阱结构的量子点材料在一维纵向上受到量子限域效应,即该量子点材料在一维纵向上的激子的活动受到粒子尺寸的限制。与非量子阱结构的量子点材料相比,非量子阱结构的量子点材料中的激子方向随机,非量子阱结构的量子点材料例如包括球状的量子点材料。而量子阱结构的量子点材料由于其在一维纵向上的激子的活动受到粒子尺寸的限制的特征,可以使得量子点材料的发光激子方向可控,以使量子点材料的发光强度更大。
典型的量子点材料包括II-VI族元素,其中,II族元素包括锌(Zn)和镉(Cd),VI族元素包括硫(S)、硒(Se)和碲(Te)。CdSe量子点材料为较广泛使用的量子点材料。
如图5所示,量子阱结构的CdSe量子点材料称为CdSe量子阱20,CdSe量子阱20受原子层数限制可以覆盖可见光区,例如,3层CdSe量子阱20的发光波长范围为458nm~462nm,4层CdSe量子阱20的发光波长为510nm~515nm,5层CdSe量子阱20的发光波长为550nm~553nm。其中,相邻的硒原子层210和镉原子层300称为一层CdSe量子阱20。
为了提升胶体量子阱的光电性质用于制造光电器件,通常会在CdSe量子阱20核结构的表面生长冠无机保护层或者壳无机保护层,冠无机保护层或者壳无机保护层以覆盖CdSe量子阱20表面的缺陷,从而提升量子点材料的荧光量子产率。
在一些示例中,通过在4层CdSe量子阱20表面生长ZnCdS保护壳层从而将其荧光量子产率提升至100%。然而,随着ZnCdS保护壳层厚度的增长,核壳结构的CdSe/ZnCdS量子阱在一维纵向上的尺寸变大,CdSe/ZnCdS量子阱的激子复合发射波长随之红移。受CdSe量子阱20本征能带的影响,CdSe/ZnCdS量子阱的发射波长大于600nm,发射波长大于600nm的光为红色光。
在一些示例中,为了制备绿光发射量子阱,采用在CdSe量子阱20的侧面生长冠状无机保护层的方法。由于只在CdSe量子阱20的侧面生长冠状无机保护层,因此不会改变CdSe量子阱20内部激子的量子限域效应,从而避免对CdSe量子阱20发射波长产生影响。该方法能有效提升CdSe量子阱20的荧光量子产率。
然而,冠状无机保护层仅对CdSe量子阱20的侧面缺陷起到钝化作用,CdSe量子阱20的上下表面缺陷依赖于有机(如羧酸)配体产生的钝化作用,在电致环境下有机配体易发生脱落,从而无法对CdSe量子阱20上下表面的缺陷起到有效的钝化作用,从而影响CdSe量子阱20发光性能。
基于此,如图5和图10所示,本公开的实施例提供一种量子点材料40,所述量子点材料40为核壳结构,其中,核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15,量子点材料40的荧光峰的波长范围为510nm~540nm。
即该量子点材料40包括:核结构和壳结构42,核结构包括CdxZn(1-x)Se,壳结构42包裹核结构形成量子点材料40。
荧光峰的波长范围为510nm~540nm的量子点材料40为发射绿光的量子点材料40,以应用于提供发射绿光的发光器件130(如图4所示)。
示例性的,量子点材料40呈量子阱结构。
示例性的,CdxZn(1-x)Se核结构30的荧光峰的波长随着x的减小而变短。
示例性的,x=0.15,该量子点材料40的核结构为Cd0.15Zn0.85Se;x=0.2,该量子点材料40的核结构为Cd0.2Zn0.8Se;x=0.3,该量子点材料40的核结构为Cd0.3Zn0.7Se;x=0.35,该量子点材料40的核结构为Cd0.35Zn0.65Se;x=0.4,该量子点材料40的核结构为Cd0.4Zn0.6Se;x=0.5,该量子点材料40的核结构为Cd0.5Zn0.5Se;x=0.6,该量子点材料40的核结构为Cd0.6Zn0.4Se;x=0.7,该量子点材料40的核结构为Cd0.7Zn0.3Se;x=0.8,该量子点材料40的核结构为Cd0.8Zn0.2Se;或者,x=0.9,该量子点材料40的核结构为Cd0.9Zn0.1Se,此处并不设限。x数值越小,镉原子31的掺杂量越少,锌原子32的掺杂量越多,CdxZn(1-x)Se核结构30的荧光峰的波长越短。
在CdxZn(1-x)Se核结构30中,镉原子31的掺杂量是指镉原子31的摩尔数与锌原子32和镉原子31的摩尔数之和的比值。锌原子32的掺杂量是指锌原子32的摩尔数与锌原子32和镉原子31的摩尔数之和的比值。
与CdSe量子阱20相比,由于锌原子32的掺杂,CdxZn(1-x)Se核结构30的荧光峰的波长会发生蓝移。而且,随着锌原子32的掺杂量的增加,CdxZn(1-x)Se核结构30的荧光峰的波长越短。
也就是说,本公开的实施例提供了一种包括硒化镉/锌合金核结构的量子点材料40,与CdSe量子阱20相比,包括硒化镉/锌合金核结构的量子点材料40的荧光峰的波长范围为510nm~540nm,以应用于提供发射绿光的发光器件130。
而且,锌原子32的掺杂量越大,CdxZn(1-x)Se形成的量子点材料40的荧光峰的波长越短。即通过锌原子32的掺杂量的变化,可以调节CdxZn(1-x)Se核结构30的荧光峰的波长,从而得到一种荧光峰的波长可以随着锌原子32的掺杂量的变化进行调节的量子点材料40,以用于发射绿光。
在一些示例中,核结构的荧光峰的波长范围为440nm~510nm。
在一些示例中,如图5所示,核结构具有:第一方向X上的尺寸、第二方向Y上的尺寸和第三方向Z上的尺寸,第一方向X、第二方向Y和第三方向Z相垂直。
CdxZn(1-x)Se核结构30在第一方向X上的尺寸为CdxZn(1-x)Se核结构30的长度和宽度中的一者,CdxZn(1-x)Se核结构30在第二方向Y的尺寸为CdxZn(1-x)Se核结构30的长度和宽度中的另一者,CdxZn(1-x)Se核结构30在第三方向Z上的尺寸为CdxZn(1-x)Se核结构30的厚度。
其中,核结构在第一方向X上的尺寸与核结构在第三方向Z上的尺寸的比值的范围为6.5~15.75;和/或,核结构在第二方向Y上的尺寸与核结构在第三方向Z上的尺寸的比值的范围为6.5~15.75。
例如,核结构在第一方向X上的尺寸与核结构在第三方向Z上的尺寸的比值为6.5、7、7.5、8、8.5、9、9.5、10、10.5、11、11.5、12、12.5、13、13.5、14、14.5、15、15.5或15.75等,此处并不设限。
例如,核结构在第二方向Y上的尺寸与核结构在第三方向Z上的尺寸的比值为6.5、7、7.5、8、8.5、9、9.5、10、10.5、11、11.5、12、12.5、13、13.5、14、14.5、15、15.5或15.75等,此处并不设限。
示例性的,图5为CdSe量子阱20与卤化锌反应形成核结构的结构图,关于CdSe量子阱20与卤化锌反应的介绍参照后续内容,此处不展开描述。核结构在第一方向X上的尺寸范围为7.8nm~12.6nm,在第二方向Y上的尺寸范围为7.8nm~12.6nm,在第三方向Z上的尺寸范围为0.8nm~1.2nm。
示例性的,CdxZn(1-x)Se核结构30在第一方向X上的尺寸为7.8nm、8nm、8.5nm、9nm、10nm、10.5nm、11nm、11.5nm、12nm或12.6nm等,此处并不设限。CdxZn(1-x)Se核结构30在第二方向Y的尺寸为7.8nm、8nm、8.3nm、9.5nm、10.4nm、10.8nm、11.2nm、11.5nm、12nm或12.6nm等,此处并不设限。CdxZn(1-x)Se核结构30在第三方向Z上的尺寸为0.8nm、0.9nm、1nm、1.1nm或1.2nm等,此处并不设限。
通过核结构在第一方向X上的尺寸、第二方向Y上的尺寸和第三方向Z上的尺寸的调整,可以调节核结构的荧光峰的波长范围。
在一些示例中,如图5所示,CdxZn(1-x)Se核结构30包括4层硒原子层210和5层镉锌原子层310,硒原子层210和镉锌原子层310沿第三方向Z交替分布。
示例性的,包括硒原子21的原子层为硒原子层210,包括镉原子31和锌原子32的原子层为镉锌原子层310。
示例性的,将CdSe量子阱20中的部分镉原子31置换为锌原子32,将镉原子层300形成镉锌原子层310,关于CdSe量子阱20形成CdxZn(1-x)Se核结构30的制备方法参照后续内容介绍,此处不展开描述。
在一些示例中,图6为CdSe量子阱20的X射线衍射成像图(X-Ray Diffractomer,XRD),横坐标表示X射线的入射角度的两倍,用2θ表示,单位为°;纵坐标是衍射强度,单位为计数/秒,表示为c/s。从图6可以看出CdSe量子阱20的2θ的峰值分别位于:24°~28°、40°~45°和47°~51°。CdSe量子阱20的2θ的三个峰值表示CdSe量子阱20为闪锌矿晶体结构。
图7为CdxZn(1-x)Se核结构30的X射线衍射成像图。CdxZn(1-x)Se核结构30的2θ的峰值分别位于:24°~30°、43°~46°和50°~54°。相比于CdSe量子阱20的2θ的峰值,CdxZn(1-x)Se核结构30的2θ的峰值向右移动,这是因为锌原子32的存在。CdxZn(1-x)Se核结构30的2θ的三个峰值表示CdxZn(1-x)Se核结构30为闪锌矿晶体结构。
在一些示例中,如图10所示,壳结构42的材料为无机材料。壳结构42可以修饰核结构的表面缺陷,从而钝化CdxZn(1-x)Se核结构30表面缺陷以提升量子点材料40的发光性能,例如,可以降低电子在跃迁过程中进入缺陷而湮灭的几率,进而提高量子点材料40的发光效率。
示例性的,壳结构42的材料包括:ZnS、ZnSe、ZnSeS和CdS中的至少一种。例如,壳结构42的材料为ZnS,量子点材料40表示为CdxZn(1-x)Se/ZnS。
在一些示例中,如图10所示,量子点材料40具有:第一方向X上的尺寸、第二方向Y上的尺寸和第三方向Z上的尺寸。
量子点材料40在第一方向X上的尺寸为量子点材料40的长度和宽度中的一者,量子点材料40在第二方向Y的尺寸为量子点材料40的长度和宽度中的另一者,量子点材料40在第三方向Z上的尺寸为量子点材料40的厚度。
示例性的,量子点材料在第一方向X上的尺寸与量子点材料在第三方向Z上的尺寸的比值范围为2.8~6;和/或,量子点材料在第二方向Y上的尺寸与量子点材料在第三方向Z上的尺寸的比值范围为2.8~6。
例如,量子点材料在第一方向X上的尺寸与量子点材料在第三方向Z上的尺寸的比值为2.8、3、3.5、4、4.5、5、5.5或6等,此处并不设限。
例如,量子点材料在第二方向Y上的尺寸与量子点材料在第三方向Z上的尺寸的比值为2.8、3、3.5、4、4.5、5、5.5或6等,此处并不设限。
示例性的,如图10所示,量子点材料40在第一方向X上的尺寸范围为10nm~15nm,在第二方向Y上的尺寸范围为10nm~15nm,在第三方向Z上的尺寸范围为2.5nm~3.5nm。
示例性的,量子点材料40在第一方向X上的尺寸为10nm、11nm、12nm、13nm、14nm或15nm等,此处并不设限。量子点材料40在第二方向Y上的尺寸为10nm、11nm、12nm、13nm、14nm或15nm等,此处并不设限。量子点材料40在第三方向Z上的尺寸为2.5nm、2.7nm、3.0nm、3.2nm或3.5nm等,此处并不设限。
示例性的,量子点材料40的尺寸分布范围应尽可能小,例如,量子点材料40的厚度标准差小于2nm,量子点材料40的长度标准差小于2nm,量子点材料40的宽度标准差小于2nm。其中,标准差是离均差平方的算术平均数的平方根。
通过在CdxZn(1-x)Se核结构30上包裹壳结构42,形成在第一方向X上的尺寸范围为10nm~15nm,在第二方向Y上的尺寸范围为10nm~15nm,在第三方向Z上的尺寸范围为2.5nm~3.5nm的量子点材料40,以提供荧光峰的波长范围为510nm~540nm的发射绿光的量子点材料40。
在一些实施例中,量子点材料还包括:配体基团,配体基团包括:油酸、1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一种与壳结构通过化学键连接后的基团。
示例性的,油酸中的羧酸基团(-COOH)中的H去除或与壳结构通过化学键连接形成配体,该配体可以称为羧酸配体;1-辛硫醇的硫醇基团(-SH)中的H去除或与壳结构通过化学键连接形成配体,该配体可以称为硫醇配体。
本公开的实施例还提供一种含有CdxZn(1-x)Se核结构30的量子点材料的制备方法,如图5、图8和图10所示,量子点材料的制备方法包括步骤S1~S6。
S1、将CdSe量子阱20分散在第一有机溶剂中,得到第一溶液。
示例性的,CdSe量子阱20的厚度范围为0.8nm~1nm。例如,CdSe量子阱20的厚度为0.8nm、0.9nm或1nm等,此处并不设限。
示例性的,如图5和图10所示,CdSe量子阱20包括:4层硒原子层210和5层镉原子层300,4层硒原子层210和5层镉原子层交叉分布形成CdSe量子阱20。此时,CdSe量子阱20可以表示为4.5层。其中,0.5是指由于上下表面富阳/阴离子带来的单个原子层,在CdSe量子阱20中,CdSe量子阱20的上下表面由镉原子31所占据,CdSe量子阱20中的0.5是CdSe量子阱20的上下表面由富阳离子Cd2+带来的单个原子层。
4.5层的CdSe量子阱20结构较稳定,形貌均一,有利于作为采用交换反应的原料制备CdxZn(1-x)Se核结构30。4.5层CdSe量子阱20的荧光峰的波长范围为508nm~513nm。通过采用荧光峰的波长范围为508nm~513nm的CdSe量子阱20作为原料制备CdxZn(1-x)Se核结构30,得到的CdxZn(1-x)Se核结构30的荧光峰的波长发生蓝移,进一步的,使用CdxZn(1-x)Se作为核结构,在核结构上包裹无机保护层的壳结构42,从而得到出射绿光的量子点材料40,具体的步骤参照后续内容,此处不展开描述。
示例性的,在第一溶液中,CdSe量子阱20的浓度范围为3g/L~6g/L。例如,在第一溶液中,CdSe量子阱20的浓度为3g/L、4g/L、5g/L或6g/L等,此处并不设限。浓度范围为3g/L~6g/L的CdSe量子阱20在第一有机溶剂中具有较好的分散性。
示例性的,第一有机溶剂包括:1-十八烯、石蜡油和橄榄油中的至少一种。其中,1-十八烯的分子式是C18H36,为无色液体,溶于热丙醇,不溶于水。石蜡油是一种矿物油,是从原油分馏中所得到的无色无味的混合物,石蜡油的主要成分为烃类,石蜡油是几种高级烷烃的混合物,主要包括正二十二烷(C22H46)和正二十八烷(C28H58),含碳元素约85%,含氢元素约14%上。橄榄油是由新鲜的油橄榄果实直接冷榨而成。
S2、向第一溶液中加入卤化锌,得到第二溶液。
示例性的,在第二溶液中,卤化锌的质量与CdSe量子阱20的质量的比值范围为3~32。例如,卤化锌的质量与CdSe量子阱20的质量的比值为3、5、8、9、10、12、16、18、22、25、28、30、31或32等,此处并不设限。
示例性的,在第二溶液中,锌原子32的摩尔浓度范围为0.05mol/L~0.2mol/L。例如,锌原子32的摩尔浓度为0.05mol/L、0.1mol/L、0.15mol/L或0.2mol/L等,此处并不设限。锌原子32的摩尔浓度范围为0.05mol/L~0.2mol/L的设置可以满足锌原子32与CdSe量子阱20充分反应的需求。
示例性的,卤化锌包括:碘化锌、氯化锌或溴化锌等,此处并不设限。
示例性的,在温度范围为80℃~100℃的真空条件下搅拌第二溶液。由于卤化锌易吸潮及易氧化,因此在真空下处理第二溶液,去除反应体系中的水氧,以防止水氧影响反应。
示例性的,在温度范围为80℃~100℃及真空条件下搅拌第二溶液1小时左右,以使卤化锌高效地释放锌离子,且保证有效的去除反应体系中的水氧。
S3、向第二溶液中加入磷源配体和脂肪胺,得到第三溶液。
示例性的,在第三溶液中,第一有机溶剂的体积与磷源配体的体积的比值范围为2.5~30。例如,第一有机溶剂的体积与磷源配体的体积的比值为2.5、3、5、8、10、12、15、18、22、23、26、28、29或30等,此处并不设限。
示例性的,第一有机溶剂的体积与脂肪胺的体积的比值范围为5~150。例如,第一有机溶剂的体积与脂肪胺的体积的比值为5、10、15、22、36、45、55、70、80、95、110、120、125、130、145或150等,此处并不设限。
示例性的,惰性气体包括氮气、氦气和氩气中的至少一种。例如,在本公开的实施例中,惰性气体可以采用成本较低的氮气。由于在步骤S2中为采用的真空条件下处理第二溶液,在该步骤中加入惰性气体,使得反应体系压力恢复常压,有利于后续磷源配体和脂肪胺的顺利加入。
示例性的,磷源配体包括:三正辛基膦、三丁基膦和三辛基氧化膦中的至少一种。其中,三正辛基膦为无色液体,分子式为C24H51P,三丁基膦为无色透明液体,化学式为C12H27P,三辛基氧化膦的分子式为C24H51OP。如图5所示,磷源配体呈弱碱性,磷源配体与CdSe量子阱20表面的镉原子31有良好的结合能力,能够帮助镉原子31实现溶剂化,即有助于镉原子31脱离CdSe量子阱20进入溶剂中。
示例性的,脂肪胺包括油胺和辛胺中的至少一种。油胺的分子式是C18H37N,为无色至淡黄色液体。辛胺分子式为C8H19N。
脂肪胺与锌原子32的结合能力较弱,能够有效地释放锌离子,从而置换出CdSe量子阱20中的镉原子31。
而且,脂肪胺为典型的纳米晶弱配体,脂肪胺与CdSe量子阱20形成配合物,有助于保持晶体表面的稳定性,并控制反应速度,以满足反应区域宽度小于晶体的尺寸,以有效的避免CdSe量子阱20的分解而导致的反应过程的失败。
S4、搅拌第三溶液,反应后得到第四溶液。
示例性的,在惰性气体氛围且温度范围为200℃~280℃的条件下,搅拌第三溶液。例如,温度为200℃、210℃、220℃、230℃、240℃、250℃、260℃或280℃等,此处并不设限。在反应过程中,为了保持反应稳定,温度浮动不超过5℃。温度范围为200℃~280℃可以保证反应顺利进行。
如图5所示,在该步骤中,CdSe量子阱20与卤化锌反应得到CdxZn(1-x)Se核结构30,CdxZn(1-x)Se核结构30分散在第四溶液中。具体的,在三正辛基膦的作用下,镉原子31脱离CdSe量子阱20进入溶剂中形成隔离子;与脂肪胺为油酸为例,由于油胺与锌原子32的结合能力较弱,能够有效地释放锌离子,锌离子进入晶格形成锌原子32,锌原子32占据该镉原子31的位置,以得到CdxZn(1-x)Se核结构30。也就是说,锌原子32与镉原子31发生了置换,具体的化学反应式如下。
Zn2++CdSe→CdxZn(1-x)Se+Cd2+
通过该步可以得到x不同的CdxZn(1-x)Se核结构30,而且,反应时长越长,得到的CdxZn(1-x)Se核结构30中的镉原子31的掺杂量越少,锌原子32的掺杂量越多。也就是说,随着反应时长的不断加长,CdxZn(1-x)Se核结构30的荧光峰的波长逐渐蓝移。
示例性的,通过从第四溶液中取样实时检测反应情况,通过吸收光谱仪来判断反应进程。4.5层的CdSe量子阱20的荧光峰的波长范围为508nm~513nm,随着反应进行,反应产物的荧光峰的波长逐渐蓝移至蓝光区,当反应产物的荧光峰的波长范围为440nm~510nm,此时,通过对反应容器水浴降温及时阻断反应。
S5、向第四溶液中加入第一极性溶剂,得到量子点材料40的核结构,核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15。
CdxZn(1-x)Se核结构30不溶于第一极性溶剂,第一极性溶剂可以使得CdxZn(1-x)Se核结构30作为沉淀物析出,第一极性溶剂例如为乙醇。
示例性的,对CdxZn(1-x)Se核结构30沉淀物进行离心分离,并多次清洗后,得到纯化的CdxZn(1-x)Se核结构30。
通过上述步骤S1~S5制备了CdxZn(1-x)Se核结构30,而且可以通过反应时长的控制以调控锌原子32的掺杂量,从而调节CdxZn(1-x)Se核结构30的荧光峰的波长。
S6、形成壳结构42,壳结构42包裹核结构,得到量子点材料40,量子点材料40的荧光峰的波长范围为510nm~540nm。
在一些示例中,如图9所示,壳结构的制备方法包括步骤:S61~S65。
S61、将阴离子前驱体分散在第二有机溶剂中,得到第五溶液。
阴离子前驱体的体积与第二有机溶剂的体积的比值范围为2×10-3~28×10-3,阴离子前驱体中的阴离子包括S和Se中的至少一种。如图10所示,以阴离子包括S为例,该阴离子形成硫原子41,硫原子41和锌原子32形成ZnS,以形成壳结构42。
前驱体定义为目标产物的雏形样品,即在经过某些步骤就可实现目标产物的前级产物,也就是说,前驱体是获得目标产物前的一种存在形式。阴离子前驱体用于提供量子点材料40中的壳结构42材料的阴离子。
示例性的,阴离子前驱体包括:1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一种。
示例性的,阴离子前驱体的体积与第二有机溶剂的体积的比值为2×10-3、10×10-3、15×10-3、18×10-3、20×10-3、23×10-3、26×10-3或28×10-3等,此处并不设限。
示例性的,第二有机溶剂包括:1-十八烯、石蜡油和橄榄油中的至少一种。例如,第一有机溶剂和第二有机溶剂可以相同。
S62、将得到的CdxZn(1-x)Se核结构30分散在第一非极性溶剂中,得到第六溶液。
示例性的,将步骤S5得到的CdxZn(1-x)Se核结构30的沉淀物加入到第一非极性溶剂,形成第六溶液。
示例性的,第一非极性溶剂的使用量为:步骤S1中的第一有机溶剂的体积与该步骤中的第一非极性溶剂的体积的比值范围为2.5~15。例如,第一有机溶剂的体积与第一非极性溶剂的体积的比值为2.5、3、3.5、5、6.5、7、8.5、10、12、13、14或15等,此处并不设限。
步骤S1中的CdSe量子阱20的质量与第一非极性溶剂的体积的比值范围为15g/L~30g/L,例如,CdSe量子阱20里的质量与第一非极性溶剂的体积的比值为15g/L、20g/L、25g/L或30g/L等,此处并不设限。
示例性的,第一非极性溶剂包括:正己烷、辛烷和十二烷中的至少一种。CdxZn(1-x)Se核结构30在第一非极性溶剂中具有较好的分散性。
S63、将第六溶液加入第三有机溶剂中,并加入阳离子前驱体和油酸,得到第七溶液;并在温度范围为90℃~100℃的真空条件下搅拌第七溶液。
其中,第三有机溶剂的体积与第六溶液的体积的比值范围为2.5~15,例如,第三有机溶剂的体积与第六溶液的体积的比值为2.5、3、3.5、5、6.5、7、8.5、10、12、13、14或15等,此处并不设限。
第三有机溶剂的体积与油酸的体积的比值范围为2.5~30,例如,第三有机溶剂的体积与油酸的体积的比值为2.5、5、8、9、12、15、17、18、20、22、24、26、28或30等,此处并不设限。
阳离子前驱体中的阳离子包括Zn和Cd中的至少一种。例如,阳离子前驱体包括:乙酸锌、油酸锌、硬脂酸锌、月桂酸锌、乙酸镉和油酸镉中的至少一种。如图10所示,以阳离子前驱体中的阳离子为Zn为例,锌原子32和硫原子41形成ZnS,以形成壳结构42。
示例性的,在第七溶液中的阳离子前驱体中的阳离子的摩尔数与第五溶液中阴离子前驱体中的阴离子的摩尔数的比值范围为1:4~1:2。例如,在第七溶液中的阳离子前驱体中的阳离子的摩尔数与第五溶液中阴离子前驱体中的阴离子的摩尔数的比值为1:4、1:3或1:2等,此处并不设限。
第三有机溶剂包括:1-十八烯、石蜡油和橄榄油中的至少一种。例如,第一有机溶剂、第二有机溶剂和第三有机溶剂均采用1-十八烯。整个反应体系通过采用相同的有机溶剂,不需要更换有机溶剂,方便实验的操作。
示例性的,在温度范围为90℃~100℃的真空条件下搅拌第七溶液,搅拌时长为1小时左右。以有效的去除水氧,以防水氧引起阳离子前驱体的氧化。
通过在温度范围为90℃~100℃的真空条件下搅拌第七溶液,可以形成阳离子的油酸溶液,例如,阳离子前驱体为乙酸锌,在温度范围为90℃~100℃的真空条件下搅拌第七溶液,在第七溶液得到油酸锌,油酸锌为壳结构42的材料提供Zn源,有利于壳结构42的形成。
S64、在惰性气体氛围且温度范围为280℃~320℃条件下,向第七溶液中加入第五溶液,反应后得到第八溶液。
示例性的,在惰性气体氛围且温度范围280℃~320℃的条件下,向第七溶液中加入第五溶液,反应时长范围为30分钟~90分钟。
例如,反应温度为280℃、285℃、290℃、295℃、300℃、305℃、310℃、315℃或320℃等,此处并不设限。温度范围为280℃~320℃的设置可以保证反应的顺利进行。
例如,反应时长为30分钟、35分钟、40分钟、45分钟、50分钟、55分钟、58分钟、60分钟、62分钟、65分钟、70分钟、75分钟、80分钟、85分钟或90分钟等,此处并不设限。
示例性的,惰性气体包括氮气、氦气和氩气中的至少一种。由于在步骤S63中为采用的真空条件下处理第七溶液,在步骤S64中加入惰性气体,使得反应体系压力恢复常压,有利于第五溶液的顺利加入。
在该步骤中,如图10所示,在惰性气体氛围且温度范围为280℃~320℃的条件下,形成包裹CdxZn(1-x)Se核结构30的壳结构42,形成量子点材料40。随着反应时间的延长,得到的壳结构42的包裹厚度越厚,形成的量子点材料40的荧光峰的波长越长。
图10为1-辛硫醇和乙酸锌反应形成ZnS壳结构42的结构图,ZnS壳结构42包裹CdxZn(1-x)Se核结构30形成量子点材料40。
S65、向第八溶液中加入第二极性溶剂,得到量子点材料40。
示例性的,第二极性溶剂包括:乙醇、甲醇、乙腈和丙酮中的至少一种。量子点材料40不溶于第二极性溶剂,第二极性溶剂可以使得量子点材料40作为沉淀物析出。然后,将量子点材料沉淀40物进行离心分离,并多次清洗,得到纯化的量子点材料40。
示例性的,将量子点材料40的沉淀物分散在第二非极性溶剂中,以保存量子点材料40,且可以将分散有量子点材料40的第二非极性溶剂用于发光器件130的发光层132的制备。例如,第二非极性溶剂包括:正己烷、辛烷和十二烷中的至少一种。
示例性的,该量子点材料40呈量子阱结构。
由上述关于量子阱结构的量子点材料40的结构的介绍可知,量子阱结构的量子点材料40在一维纵向上受到量子限域效应,通过将荧光峰的波长范围为440nm~510nm的CdxZn(1-x)Se核结构30的表面包裹无机保护壳层,得到量子点材料40,与CdxZn(1-x)Se核结构30相比,量子点材料40在一维纵向上的尺寸变大,量子点材料40的激子复合发射波长会发生红移,从而得到荧光峰的波长范围为510nm~540nm的发射绿光的量子点材料40,以应用于提供发射绿光的发光器件130。
因此,本公开的实施例通过步骤S61~S65在CdxZn(1-x)Se核结构30的表面包裹了壳结构42,形成了荧光峰的波长范围为510nm~540nm的量子点材料40。而且,该量子点材料40发光波长具有可调的灵活性,使得量子点材料40发光波长不完全依赖于晶体的层数的限制。
根据上述步骤S1~S6中的量子点材料的制备方法,提供以下实施例制备CdxZn(1-x)Se/ZnS量子点材料40。如图5、图8和图11所示,CdxZn(1-x)Se/ZnS量子点材料的制备方法包括步骤:R1~R10。
R1、在反应器中,将20mg~40mg的CdSe量子阱20分散在10mL的1-十八烯中,得到第一溶液。
示例性的,CdSe量子阱20为4.5层。关于4.5层的CdSe量子阱20的介绍可以参照上述内容,此处不再赘述。
R2、向第一溶液中加入0.5mmol~2mmol的碘化锌,得到第二溶液,并在80℃~100℃的真空条件下搅拌第二溶液。
在80℃~100℃的真空条件下搅拌第二溶液以除去反应体系中的水氧。
R3、在一小时内,将反应器中变为氮气氛围,并升温,当反应物温度达100℃时,向第二溶液中加入0.5mL~2mL的三正辛基膦和0.1mL~1mL的油胺,得到第三溶液。
三正辛基膦作为磷源配体,该磷源配体呈弱碱性,磷源配体与CdSe量子阱20表面的镉原子31有良好的结合能力,能够帮助镉原子31实现溶剂化,即有助于镉原子31脱离CdSe量子阱20进入溶剂中。
碘化锌与油胺的结合能力较弱,这样能够有效地释放锌离子,锌离子置换出CdSe量子阱20中的镉原子31。而且,油胺为典型的纳米晶弱配体,油胺与CdSe量子阱20形成配合物,有助于保持晶体表面的稳定性,并控制反应速度,以满足反应区域宽度小于晶体的尺寸,以有效的避免CdSe量子阱20的分解而导致的反应过程的失败。
R4、在温度为220℃的氮气条件下搅拌第三溶液,以得到第四溶液。
示例性的,反应过程中控制温度稳定,上下浮动不超过5℃。
在该步骤中,CdSe量子阱20与碘化锌反应得到CdxZn(1-x)Se核结构30。
图12为不同反应时长得到的CdxZn(1-x)Se核结构30的光致发光的光谱图。其中,横坐标表示发光波长,单位为nm。纵坐标表示荧光强度,单位为a.u.(Absorbance Unit,吸光度)。从图12中可以看出,随着反应时长的加长,CdxZn(1-x)Se核结构30的荧光峰的波长逐渐蓝移。当反应时长为50分钟时,得到的CdxZn(1-x)Se核结构30的荧光峰的波长约470nm。
图13为CdSe量子阱20与碘化锌反应40分钟的X射线衍射成像图,横坐标表示尺寸,单位为nm;纵坐标表示个数。其中,横坐标表示的尺寸为CdSe量子阱20的长度或宽度的尺寸,以及CdxZn(1-x)Se核结构30的长度或宽度的尺寸。从图13可以看出,CdSe量子阱20的尺寸分布在9nm~14nm之间,且CdSe量子阱20的尺寸主要分布在10.5nm~12.3nm之间,CdxZn(1-x)Se核结构30的尺寸分布在6nm~14nm之间,且CdxZn(1-x)Se核结构30的尺寸主要分布在8.8nm~11.6nm之间。因此,与CdSe量子阱20的尺寸相比,CdxZn(1-x)Se核结构30的尺寸相对较小。
在CdSe量子阱20与碘化锌的反应中,图14为形成的CdxZn(1-x)Se核结构30中的镉原子31(表示为Cd)的质量含量和锌原子32(表示为Zn)的质量含量随反应时长的变化图。该图也可以称为电感耦合等离子体发射光谱图,横坐标表示反应时长,单位为分钟;纵坐标表示质量含量百分比。其中,镉原子31的质量含量为镉原子31的质量与镉原子31的质量和锌原子32的质量之和的比值;锌原子32的质量含量为锌原子32的质量与镉原子31的质量和锌原子32的质量之和的比值。从图14可以看出,随着反应时长的加长,在CdxZn(1-x)Se核结构30中,锌原子32的质量含量逐渐增加,镉原子31的质量含量逐渐减少。
因此,通过控制该步骤的反应时长可以得到CdxZn(1-x)Se核结构30的荧光峰的波长范围为440nm~510nm,CdxZn(1-x)Se核结构30可以用于形成出射绿光的量子点材料40。
示例性的,通过该步骤得到的核结构的x的取值为0.47,即核结构的材料为Cd0.47Zn0.53Se。
R5、向第四溶液中加入乙醇,使得CdxZn(1-x)Se核结构30以沉淀物的形式析出。
示例性的,通过离心机离心分离得到CdxZn(1-x)Se核结构30的沉淀物,并采用乙醇多次清洗CdxZn(1-x)Se核结构30的沉淀物,以纯化CdxZn(1-x)Se核结构30。
R6、将35μL~140μL的1-辛硫醇分散在5mL~10mL的1-十八烯中,得到第五溶液。
其中,1-辛硫醇用于提供硫源,硫源用于形成ZnS壳结构42。
R7、将步骤R5得到的CdxZn(1-x)Se核结构30的沉淀物分散在1mL~2mL己烷中,得到第六溶液。
图15为CdxZn(1-x)Se核结构30的扫描电镜图,从图15中可以看出,CdxZn(1-x)Se核结构30尺寸较均匀,CdxZn(1-x)Se核结构30的长度和宽度的范围为7.8nm~12.6nm。
CdxZn(1-x)Se核结构30在己烷中具有较好的分散性,因此,己烷可用于保存CdxZn(1-x)Se核结构30。
R8、在反应烧瓶中,将第六溶液加入5mL~15mL的1-十八烯,然后加入乙酸锌和0.5mL~2mL的油酸,得到第七溶液;之后在100℃的真空条件下搅拌第七溶液约1小时。
乙酸锌为阳离子前驱体,用于提供锌源,乙酸锌与油酸混合得到油酸锌,油酸锌中的锌离子用于形成ZnS壳结构42。
R9、在温度为305℃的氮气条件下,向第七溶液中滴入第五溶液,反应得到第八溶液。
示例性的,反应时长范围为30分钟~90分钟。
通过反应温度设定为305℃,以确保1-辛硫醇中的碳-硫化学键可以断裂,从而提供硫原子41,以用于形成ZnS壳结构42。
图16为不同反应时长得到的量子点材料40的光致发光的光谱图。其中,横坐标表示发光波长,单位为nm。纵坐标表示荧光强度,单位为a.u.。从图16可以看出,随着反应时长的加长,量子点材料40的荧光峰的波长逐渐红移。因此,反应时长范围为30分钟~90分钟,可以得到荧光峰的波长范围为510nm~540nm的量子点材料40,该量子点材料40可以用于出射绿光。
R10、向第八溶液中加入乙醇,使得量子点材料40以沉淀物的形式析出。
该量子点材料40为CdxZn(1-x)Se/ZnS量子点材料40,该量子点材料40呈量子阱结构。该量子点材料40的荧光量子产率范围为60%~90%,即量子点材料40的荧光量子产率大于或等于60%,小于或等于90%;例如,量子点材料40的荧光量子产率大于80%。
图17为CdxZn(1-x)Se/ZnS量子点材料40的扫描电镜图,从图17中可以看出,CdxZn(1-x)Se/ZnS量子点材料40尺寸较均匀,CdxZn(1-x)Se/ZnS量子点材料40的长度和宽度的范围为10nm~15nm。
通过上述步骤R1~R10形成了CdxZn(1-x)Se/ZnS量子点材料40。
该量子点材料40的溶液体系中存在油酸及1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一者,因此,油酸及1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一者会通过化学键连接在壳结构的表面,形成羧酸配体或硫醇配体。
示例性的,然后将CdxZn(1-x)Se/ZnS量子点材料40的沉淀物分散在正辛烷中,以保存CdxZn(1-x)Se/ZnS量子点材料40,且可以将分散有CdxZn(1-x)Se/ZnS量子点材料40的正辛烷溶液用于发光器件130的发光层132的制备。
在另一些实施例中,在步骤R3中不加入油胺及其他脂肪胺,无法得到CdxZn(1-x)Se核结构30。也就是说,在不添加油胺及其他脂肪胺的条件下,无法得到CdxZn(1-x)Se/ZnS量子点材料40。
这是由于脂肪胺与锌原子32的结合能力较弱,能够有效地释放锌离子,从而置换出CdSe量子阱20中的镉原子31。
而且,脂肪胺为典型的纳米晶弱配体,脂肪胺与CdSe量子阱20形成配合物,有助于保持晶体表面的稳定性,并控制反应速度,以满足反应区域宽度小于晶体的尺寸,以有效的避免CdSe量子阱20的分解而导致的反应过程的失败。
在又一些实施例中,在步骤R3中不加入三正辛基膦以及其他叔膦类有机物,无法得到CdxZn(1-x)Se核结构30。也就是说,在不添加三正辛基膦以及其他叔膦类有机物的条件下,无法得到CdxZn(1-x)Se/ZnS量子点材料40。
三正辛基膦以及其他叔膦类有机物作为磷源配体,磷源配体与CdSe量子阱20表面的镉原子31有良好的结合能力,能够帮助镉原子31实现溶剂化,即有助于镉原子31脱离CdSe量子阱20进入溶剂中。在该反应体系中,叔膦类有机物可以保证反应的顺利进行。
在一些示例中,如图18所示,发光器件130包括:层叠设置的第一电极131、空穴注入层134、空穴传输层135、发光层132、电子传输层136和第二电极133。发光层132的材料包括如上任一实施例所提供的CdxZn(1-x)Se/ZnS量子点材料40,该发光器件130用于出射绿光。
示例性的,空穴注入层134的材料可以包括聚3,4-乙烯二氧噻吩、聚苯乙烯磺酸、盐PEDOT:PSS4083(聚3,4-乙烯二氧噻吩/聚苯乙烯磺酸盐)或者其他适用于空穴注入的化合物等,此处并不设限。
示例性的,空穴传输层135的材料可以包括聚(9,9-二辛基芴-co-N-(4-丁基苯基)二苯胺)(TFB),或聚乙烯咔唑(PVK)等,此处并不设限。
示例性的,电子传输层136可以包括氧化锌或氧化镁锌的纳米粒子薄膜或溶胶凝胶薄膜等,此处并不设限。
通过空穴注入层134、空穴传输层135和电子传输层136的设置可以提高发光器件130载流子传输性能,以提高发光器件130的发光性能。
图19为发光器件130的电流效率曲线图,横坐标表示电压,单位为V;纵坐标表示电流效率,单位为cd/A。从图19可以看出,发光器件130的电流效率高达82.1%。
图20为发光器件130的外量子效率(External Quantum Efficiency,EQE)曲线图,横坐标表示发光亮度,单位为cd/m2;纵坐标表示外量子效率。从图20可以看出,发光器件130的最高外量子效率可达20%,并分布范围为10%~20%。
该发光器件130最大亮度超过300000cd/m2
以上所述,仅为本公开的具体实施方式,但本公开的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本公开揭露的技术范围内,想到变化或替换,都应涵盖在本公开的保护范围之内。因此,本公开的保护范围应以所述权利要求的保护范围为准。

Claims (27)

  1. 一种量子点材料,所述量子点材料为核壳结构,其中,核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15,所述量子点材料的荧光峰的波长范围为510nm~540nm。
  2. 根据权利要求1所述的量子点材料,其中,所述量子点材料具有:第一方向上的尺寸、第二方向上的尺寸和第三方向上的尺寸,所述第一方向、所述第二方向和所述第三方向相垂直;
    其中,所述量子点材料在所述第一方向上的尺寸与所述量子点材料在所述第三方向上的尺寸的比值范围为2.8~6;和/或,所述量子点材料在所述第二方向上的尺寸与所述量子点材料在所述第三方向上的尺寸的比值范围为2.8~6。
  3. 根据权利要求2所述的量子点材料,其中,所述量子点材料在所述第一方向上的尺寸范围为10nm~15nm,在所述第二方向上的尺寸范围为10nm~15nm,在所述第三方向上的尺寸范围为2.5nm~3.5nm。
  4. 根据权利要求1~3任一项所述的量子点材料,其中,所述核结构的荧光峰的波长范围为440nm~510nm。
  5. 根据权利要求1~4任一项所述的量子点材料,其中,所述核结构具有:第一方向上的尺寸、第二方向上的尺寸和第三方向上的尺寸;
    其中,所述核结构在所述第一方向上的尺寸与所述核结构在所述第三方向上的尺寸的比值的范围为6.5~15.75;和/或,所述核结构在所述第二方向上的尺寸与所述核结构在所述第三方向上的尺寸的比值的范围为6.5~15.75。
  6. 根据权利要求5所述的量子点材料,其中,所述核结构在所述第一方向上的尺寸范围为7.8nm~12.6nm,在所述第二方向上的尺寸范围为7.8nm~12.6nm,在所述第三方向上的尺寸范围为0.8nm~1.2nm。
  7. 根据权利要求1~6任一项所述的量子点材料,其中,所述核结构包括:4层硒原子层和5层镉锌原子层,硒原子层和镉锌原子层沿第三方向交替分布。
  8. 根据权利要求1~7任一项所述的量子点材料,其中,所述核结构为闪锌矿晶体结构。
  9. 根据权利要求1~8任一项所述的量子点材料,其中,在X射线衍射成像图中,所述核结构的X射线的入射角度的两倍的峰值有三个,分别位于:24°~30°、43°~46°和50°~54°。
  10. 根据权利要求1~9任一项所述的量子点材料,其中,所述量子点材料的荧光峰的波长随着x的减小而变短。
  11. 根据权利要求1~10任一项所述的量子点材料,其中,壳结构的材料包括:ZnS、ZnSe、ZnSeS和CdS中的至少一种。
  12. 根据权利要求1~11任一项所述的量子点材料,其中,壳结构包裹所述核结构。
  13. 根据权利要求1~12任一项所述的量子点材料,其中,所述量子点材料呈量子阱结构。
  14. 根据权利要求1~13任一项所述的量子点材料,其中,所述量子点材料还包括:配体基团,所述配体基团包括:油酸、1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一种与壳结构通过化学键连接后的基团。
  15. 一种量子点材料的制备方法,包括:
    将CdSe量子阱分散在第一有机溶剂中,得到第一溶液;
    向所述第一溶液中加入卤化锌,得到第二溶液;
    向所述第二溶液中加入磷源配体和脂肪胺,得到第三溶液;
    搅拌所述第三溶液,反应后得到第四溶液;
    向所述第四溶液中加入第一极性溶剂,得到所述量子点材料的核结构,所述核结构的材料包括:CdxZn(1-x)Se,其中,1>x≥0.15;
    形成壳结构,所述壳结构包裹所述核结构,得到量子点材料,所述量子点材料的荧光峰的波长范围为510nm~540nm。
  16. 根据权利要求15所述的量子点材料的制备方法,其中,
    在所述第一溶液中,所述CdSe量子阱包括:4层硒原子层和5层镉原子层,硒原子层和镉原子层交替分布;
    在所述第二溶液中,所述卤化锌的质量与所述CdSe量子阱的质量的比值范围为3~32;且在温度范围为80℃~100℃的真空条件下搅拌所述第二溶液;
    在所述第三溶液中,所述第一有机溶剂的体积与所述磷源配体的体积的比值范围为2.5~30,所述第一有机溶剂的体积与所述脂肪胺的体积的比值范围为5~150;
    所述搅拌所述第三溶液,为在惰性气体氛围且温度范围为200℃~280℃的条件下进行。
  17. 根据权利要求15或16所述的量子点材料的制备方法,其中,所述卤化锌包括:碘化锌、氯化锌和溴化锌中的至少一种。
  18. 根据权利要求15~17任一项所述的量子点材料的制备方法,其中,所述磷源配体包括:三正辛基膦、三丁基膦和三辛基氧化膦中的至少一种;和/或,
    所述脂肪胺包括:油胺和辛胺中的至少一种。
  19. 根据权利要求15~18任一项所述的量子点材料的制备方法,其中,所述第一有机溶剂包括:1-十八烯、石蜡油和橄榄油中的至少一种。
  20. 根据权利要求15~19任一项所述的量子点材料的制备方法,其中,所述第一极性溶剂包括:乙醇、甲醇、乙腈和丙酮中的至少一种。
  21. 根据权利要求15~20任一项所述的量子点材料的制备方法,其中,所述形成壳结构包括:
    将阴离子前驱体分散在第二有机溶剂中,得到第五溶液;其中,所述阴离子前驱体的体积与所述第二有机溶剂的体积的比值范围为2×10-3~28×10-3,所述阴离子前驱体中的阴离子包括S和Se中的至少一种;
    将得到的所述核结构CdxZn(1-x)Se分散在第一非极性溶剂中,得到第六溶液;
    将所述第六溶液加入第三有机溶剂中,并加入阳离子前驱体和油酸,得到第七溶液;并在温度范围为90℃~100℃的真空条件下搅拌所述第七溶液;其中,所述第三有机溶剂的体积与所述第六溶液的体积的比值范围为2.5~15;所述第三有机溶剂的体积与所述油酸的体积的比值范围为2.5~30;所述阳离子前驱体中的阳离子包括Zn和Cd中的至少一种;
    在惰性气体氛围且温度范围为280℃~320℃条件下,向所述第七溶液中加入所述第五溶液,反应后得到第八溶液;
    向所述第八溶液中加入第二极性溶剂,得到所述量子点材料,所述量子点材料的荧光峰的波长范围为510nm~540nm。
  22. 根据权利要求21所述的量子点材料的制备方法,其中,所述阴离子前驱体包括:1-辛硫醇、2-乙基-己硫醇、1-癸硫醇、1-十二硫醇、三丁基膦硒和1-十八烯硒中的至少一种。
  23. 根据权利要求21或22所述的量子点材料的制备方法,其中,所述阳离子前驱体包括:乙酸锌、油酸锌、硬脂酸锌、月桂酸锌、乙酸镉和油酸镉中的至少一种。
  24. 根据权利要求21~23任一项所述的量子点材料的制备方法,其中,所述第一非极性溶剂包括:正己烷、辛烷和十二烷中的至少一种。
  25. 根据权利要求21~24任一项所述的量子点材料的制备方法,其中,所述在惰性气体氛围且温度范围280℃~320℃的条件下,向所述第七溶液中加入所述第五溶液,反应时长范围为30分钟~90分钟。
  26. 一种发光器件,包括:相对设置的第一电极和第二电极,以及位于所述第一电极和所述第二电极之间的发光层;
    其中,所述发光层包括:如权利要求1~14中任一项所述的量子点材料。
  27. 一种显示面板,包括:
    如权利要求26所述的发光器件;
    像素驱动电路,用于驱动所述发光器件发光。
PCT/CN2024/134546 2024-03-27 2024-11-26 量子点材料及其制备方法、发光器件、显示面板 Pending WO2025200513A1 (zh)

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