CN116925768A - Quantum dot, preparation method thereof, light emitting diode and display device - Google Patents

Quantum dot, preparation method thereof, light emitting diode and display device Download PDF

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CN116925768A
CN116925768A CN202210323258.XA CN202210323258A CN116925768A CN 116925768 A CN116925768 A CN 116925768A CN 202210323258 A CN202210323258 A CN 202210323258A CN 116925768 A CN116925768 A CN 116925768A
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quantum dot
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precursor
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shell
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聂志文
丘洁龙
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TCL Technology Group Co Ltd
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    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
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    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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Abstract

The application discloses a quantum dot, a preparation method thereof, a light emitting diode and a display device. The preparation method of the quantum dot comprises the following steps: providing a mixed solution, wherein the mixed solution comprises a coordination solution, a non-coordination solution and a quantum dot core; removing a non-coordinating solution with a preset proportion; providing a shell cation precursor and a shell anion precursor, and carrying out quantum dot shell growth; wherein the boiling point of the complexing solution is higher than the boiling point of the non-complexing solution. The non-coordination solution with low boiling point is removed, the boiling point of the reaction system is improved, and the shell layer grows at high temperature, so that the crystallinity of the core-shell quantum dot is improved, and the luminous efficiency of the quantum dot is improved.

Description

Quantum dot, preparation method thereof, light emitting diode and display device
Technical Field
The application relates to the technical field of quantum dots, in particular to a quantum dot, a preparation method thereof, a light emitting diode and a display device.
Background
The quantum dots have the characteristics of wide excitation spectrum, narrow emission spectrum, high stability, high quantum dot yield, continuous spectrum, excellent solution processing property and the like, and thus the quantum dots are widely focused in the productivity field. Quantum dot Light Emitting diodes (Quantum Dot Light Emitting Diodes, QLEDs) that target quantum dots have become the most emerging technology for Organic Light-Emitting diodes (OLEDs) that have potential for development. The exposed quantum dot core has small particle size, more surface dangling bonds, and the surface is easily oxidized to generate defects, so that non-radiative transition is initiated, the luminous performance of the quantum dot is reduced, and the wide application of the quantum dot is limited. Therefore, the shell layer grown on the surface of the quantum dot core not only can effectively passivate the surface defect of the core, but also can effectively reduce the influence of external environment, reduce the sensitivity of the quantum dot to the external environment, and improve the stability and luminous efficiency of the quantum dot.
The hydrocarbon such as octadecene is used as a non-coordination solution for quantum dot synthesis, so that adverse factors such as high price of a precursor, inflammability, explosiveness, strict operation requirements and the like in the quantum dot synthesis process are solved. Meanwhile, the concentration of the precursor and the ligand can be effectively regulated by introducing the non-coordination solution, so that the formation and growth regulation means of the quantum dots are greatly enriched, and a foundation is laid for high-quality quantum dot synthesis. However, the boiling point of the non-coordinating solution is generally low, and the growth temperature of the quantum dots is basically dependent on the boiling point of the reaction solution system consisting of the non-coordinating solution and the coordinating solution. The high-temperature shell growth can promote the crystallinity of the core-shell quantum dot, so how to provide a method for improving the existing shell growth temperature without changing the shell growth environment is urgently needed.
Disclosure of Invention
The application provides a quantum dot, a preparation method thereof, a light emitting diode and a display device, which can solve the problem that the crystallization of a core-shell quantum dot is affected by low growth temperature of a shell layer.
The application provides a preparation method of quantum dots, which comprises the following steps: providing a mixed solution, wherein the mixed solution comprises a coordination solution, a non-coordination solution and a quantum dot core; removing a non-coordinating solution with a preset proportion; providing a shell cation precursor and a shell anion precursor, and carrying out quantum dot shell growth; wherein the boiling point of the complexing solution is higher than the boiling point of the non-complexing solution.
Alternatively, in some embodiments of the present application, the non-coordinating solution may have a boiling point of 200 to 320 ℃, 220 to 300 ℃, or 250 to 270 ℃ at one atmosphere;
alternatively, in some embodiments of the present application, the coordinating solution may have a boiling point of 320 to 400 ℃, 330 to 390 ℃, or 350 to 370 ℃ at one atmosphere. Optionally, in some embodiments of the application, the method of removing a non-coordinating solution comprises: vaporizing the non-coordinating solution under a first vacuum condition and/or a first temperature condition to thereby remove the non-coordinating solution.
Alternatively, in some embodiments of the present application, the vacuum level may be 10 under the first vacuum condition -4 ～10 - 6 Torr, may be 5×10 -6 ～5×10 -5 Torr, also can be 10 -5 Torr。
Alternatively, in some embodiments of the present application, the temperature may be 100 to 350 ℃, or 150 to 300 ℃, or 200 to 250 ℃ under the first vacuum condition.
Alternatively, in some embodiments of the present application, the temperature may be 320 to 380 ℃, 330 to 370 ℃, or 340 to 360 ℃ under the first temperature condition.
Alternatively, in some embodiments of the present application, the concentration of the quantum dot core may be 10 to 200mg/mL, 20 to 150mg/mL, or 50 to 100mg/mL, based on the total volume of the mixed solution.
Alternatively, in some embodiments of the application, the volume ratio of non-coordinating solution to coordinating solution may be from 0.5 to 5:1, may be 0.8 to 3:1, 1 to 2:1.
optionally, in some embodiments of the application, the preset proportion is 95% or more.
Alternatively, in some embodiments of the application, the predetermined proportion is 100%.
Alternatively, in some embodiments of the application, the non-coordinating solution is selected from one or more of an aliphatic hydrocarbon having 6 to 40 carbon atoms, an aromatic hydrocarbon having 6 to 30 carbon atoms, a nitrogen-containing heterocyclic compound, or an aromatic ether having 12 to 22 carbon atoms.
Alternatively, in some embodiments of the application, the aliphatic hydrocarbon comprises hexadecane, octadecane, octadecene, eicosene, or squalane.
Alternatively, in some embodiments of the application, the aromatic hydrocarbon comprises phenyldodecane, phenyltetradecane, or phenylhexadecane.
Alternatively, in some embodiments of the application, the nitrogen-containing heterocyclic compound includes pyridine.
Alternatively, in some embodiments of the application, the aromatic ether comprises a phenyl ether or a benzyl ether.
Alternatively, in some embodiments of the present application, the complexing solution is selected from one or more of saturated or unsaturated fatty acids having from 5 to 30 carbon atoms, linear or branched alkylamines having from 1 to 10 carbon atoms, cycloaliphatic amines having from 4 to 8 carbon atoms, aromatic amines having from 5 to 20 carbon atoms, linear or branched alkylphosphines having from 1 to 10 carbon atoms, or linear or branched alkylphosphines having from 1 to 10 carbon atoms.
Alternatively, in some embodiments of the application, the saturated or unsaturated fatty acids include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, or oleic acid.
Alternatively, in some embodiments of the application, the precursors required for the quantum dot nuclear reaction include a nuclear layer cationic precursor selected from group II element precursors and a nuclear layer anionic precursor selected from group VI element precursors.
Alternatively, in some embodiments of the application, the shell cationic precursor is selected from group II element precursors and the shell anionic precursor is selected from group VI element precursors.
Optionally, in some embodiments of the present application, the group II precursor is selected from at least one of a Zn precursor, a Cd precursor, and an Hg precursor.
Optionally, in some embodiments of the application, the precursor of the group VI element is selected from at least one of a precursor of an S element, a precursor of a Se element, or a precursor of a Te element.
Alternatively, in some embodiments of the application, the quantum dot core and quantum dot shell compounds comprise CdS, cdSe, cdTe, znS, znSe, znTe, hgS, hgSe, hgTe, cdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, cdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe, hgZnSTe.
Alternatively, in some embodiments of the application, the quantum dots include CdSe/ZnSe core-shell quantum dots, cdZnSe/ZnSe core-shell quantum dots, cdSe/CdZnSe/ZnSe core-shell quantum dots, cdTe/CdZnTe/ZnSe core-shell quantum dots, cdTe/CdZnSe/ZnSe core-shell quantum dots, or CdTe/CdZnTe/ZnSe core-shell quantum dots, ceZnSe/CdZnSe/ZnSe/ZnS, cdZnSe/CdZnSe/CdZnS.
Correspondingly, the application also provides the quantum dot prepared by the preparation method.
In addition, the application also provides a light-emitting diode which comprises an anode layer, a cathode layer and a light-emitting layer arranged between the anode layer and the cathode layer, wherein the material of the light-emitting layer comprises the quantum dots prepared by the preparation method or the quantum dots.
Alternatively, in some embodiments of the present application, the thickness of the light emitting layer may be 30 to 180nm, 50 to 150nm, or 70 to 100nm.
Alternatively, in some embodiments of the application, the material of the anode layer includes ITO, IZO, ITZO, ICO, snO 2 、In 2 O 3 、CdZnO、FSnO 2 、InSnO 2 、GaSnO 2 One or more of AZO, ni, pt, au, ag, ir or CNT.
Alternatively, in some embodiments of the application, the cathode layer comprises Ca, ba, ca/Al, liF/Ca, L iF/Al、BaF 2 /Al、CsF/Al、CaCO 3 /Al、BaF 2 Ca/Al, al, mg, au Mg or Ag, one or more of Mg.
In addition, the application also provides a display device which comprises the light emitting diode.
The method for removing the non-coordination solution in the quantum dot synthesis process has the following beneficial effects:
1) After the nucleation of the quantum dots is finished, removing the non-coordination solution with a lower boiling point in the quantum dot cores, and leaving the original coordination solution in the reaction solution. Because the boiling point of the coordination solution is higher than that of the non-coordination solution, after the non-coordination solution is removed, the temperature of the reaction system can reach higher temperature, and the crystallinity of the quantum dots is improved;
2) The method for improving the reaction temperature does not need to additionally introduce other solutions, can effectively avoid adverse effects of the newly introduced solutions on the whole reaction system, and keeps the original growth environment of the quantum dot reaction system;
3) The method is very simple, quick and effective, and can open up a new synthesis idea for preparing high-quality quantum dots.
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In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method of preparing quantum dots;
FIG. 2 is a schematic diagram of a front-mounted LED;
fig. 3 is a schematic view of the structure of an inverted light emitting diode.
Detailed Description
The following description of the technical solutions in the embodiments of the present application will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to fall within the scope of the application.
The application provides a quantum dot, a preparation method thereof, a light emitting diode and a display device. The following will describe in detail. The following description of the embodiments is not intended to limit the preferred embodiments.
In the present application, aliphatic compound means that the hydrocarbon group in the compound is a straight chain structure; alicyclic means that the hydrocarbyl group in the compound contains a carbocyclic ring; the aromatic compound means a compound having an aromatic ring structure.
The embodiment of the application provides a preparation method of quantum dots, which is shown in fig. 1 and comprises the following steps: s1, providing a mixed solution, wherein the mixed solution comprises a coordination solution, a non-coordination solution and a quantum dot core; s2, removing a non-coordination solution with a preset proportion; s3, providing a shell cation precursor and a shell anion precursor, and carrying out quantum dot shell growth. Wherein the boiling point of the complexing solution is higher than the boiling point of the non-complexing solution.
Since the boiling point of the coordination solution is often higher than that of the non-coordination solution during the synthesis of the quantum dots, the boiling point of the final reaction solution is lower than that of the coordination solution. In order to increase the crystallinity of the quantum dots, high Wen Keceng growth appears to be very necessary. The introduction of a high boiling point solution is a very effective solution for increasing the growth temperature of the shell, however, the high boiling point solution may react with the solution in the original solution, and the generated byproducts may affect the luminescence performance of the quantum dots. Such as: an oleylamine solution having a high boiling point, the introduction of which can raise the temperature of the entire reaction system. However, the oleylamine reacts with the original carboxyl ligand in the reaction system, so that the generated water is easy to oxidize the surface of the quantum dot, and an extra defect state is introduced, thereby reducing the luminous efficiency. In addition, the introduction of the high boiling point solution can change the growth environment of the whole shell layer, influence the growth orientation of the shell layer along the surface of the core, influence the size and the morphology of the final quantum dot, and even influence the lattice perfection degree of the core-shell quantum dot.
Therefore, the application is mainly based on the thought of high Wen Keceng growth, and the growth temperature of the shell layer is improved by not introducing extra solution to influence the growth environment of the reaction system, thereby achieving the purpose of improving the crystallinity and luminous efficiency of the whole core-shell quantum dot. Firstly, after the nucleation of the quantum dots is finished, removing a non-coordination solution with a lower boiling point in the quantum dot cores, and leaving an original coordination solution in the reaction solution. Since the boiling point of the coordination solution is higher than that of the non-coordination solution, the temperature of the reaction system can reach a higher temperature after the non-coordination solution is removed. And secondly, the method for improving the reaction temperature does not need to additionally introduce other solutions, so that adverse effects of the newly introduced solutions on the whole reaction system can be effectively avoided, and the original growth environment of the quantum dot reaction system is maintained. Finally, the method is very simple, quick and effective, and can open up a new synthesis idea for preparing high-quality quantum dots.
In step S1, the quantum dot core may be obtained by adding a core layer anion precursor and a core layer cation precursor to a mixed solution containing a coordination solution and a non-coordination solution, and reacting the mixed solution. The mixed solution comprises a coordination solution, a non-coordination solution and a quantum dot core, and a nuclear layer anion precursor or a nuclear layer cation precursor which is not reacted in the quantum dot core reaction process can also exist.
Specifically, the concentration of the quantum dot core can be 10-200 mg/mL, 20-150 mg/mL, or 50-100 mg/mL based on the total volume of the mixed solution. The volume ratio of the non-coordinating solution to the coordinating solution may be 0.5-5: 1, may be 0.8 to 3:1, 1 to 2:1.
in step S2, the method of removing the non-coordinating solution includes: vaporizing the non-coordinating solution under a first vacuum condition and/or a first temperature condition to thereby remove the non-coordinating solution. The non-coordination solution is removed by vacuum pumping to reduce the air pressure or raise the temperature, and by utilizing the different boiling points of the non-coordination solution and the coordination solution, the coordination solution is in a liquid state, and the non-coordination solution is in a gas state.
Specifically, the coordinating solution has a boiling point that is higher than the boiling point of the non-coordinating solution. For example, at one atmosphere, the non-coordinating solution may have a boiling point of 200 to 320 ℃, 220 to 300 ℃, or 250 to 270 ℃; the boiling point of the complexing solution may be 320-400 ℃, 330-390 ℃, or 350-370 ℃ at one atmosphere.
Further, under the first vacuum condition, the vacuum degree may be 10 -4 ～10 -6 Torr, may be 5×10 -6 ～5×10 -5 Torr, also can be 10 -5 Torr。
Further, under the first vacuum condition, the temperature may be 100 to 350 ℃, may be 150 to 300 ℃, or may be 200 to 250 ℃. In the temperature range, the non-coordination solution can be effectively removed, the coordination solution is kept from being removed, the growth temperature of the final core-shell quantum dot is improved, and meanwhile, the existence of the coordination solution in a reaction system is ensured, so that the growth of a subsequent shell layer is not influenced.
Further, under the first temperature condition, the temperature may be 320-380 ℃, 330-370 ℃, or 340-360 ℃. The flow rate of the gas is precisely controlled during the exhausting process, and if the flow rate is too fast, the non-coordination solution and the coordination solution can be taken away together. Too slow a flow rate does not achieve the removal of the non-coordinating solution. In order to accelerate the removal of the non-coordinating solution, the connected return pipe is not a straight return pipe, but a bent pipe is adopted, and the angle of the bent pipe is 30-90 degrees. The bent pipe part connected with the reaction system is heated at 50-200 ℃, and the temperature is not too high, which causes that the coordination solution is taken away together with the non-coordination solution, and too low, which causes that the non-coordination solution is not evaporated cleanly, so that the reaction temperature is less than the preset temperature. The end is mainly aimed at condensing gaseous non-coordination solution to avoid pollution caused by direct discharge into atmosphere.
Specifically, the preset proportion may be 95% or more, and further, the preset proportion may be 100%.
In some embodiments of the application, the non-coordinating solution is selected from one or more of an aliphatic hydrocarbon having 6 to 40 carbon atoms, an aromatic hydrocarbon having 6 to 30 carbon atoms, a nitrogen-containing heterocyclic compound, or an aromatic ether having 12 to 22 carbon atoms.
Further, the aliphatic hydrocarbon includes hexadecane, octadecane, octadecene, eicosene, or squalane.
Further, the aromatic hydrocarbon includes phenyldodecane, phenyltetradecane, or phenylhexadecane.
Further, the nitrogen-containing heterocyclic compound includes pyridine.
Further, the aromatic ether includes phenyl ether or benzyl ether.
In some embodiments of the present application, the complexing solution is selected from one or more of saturated or unsaturated fatty acids having 5 to 30 carbon atoms, linear or branched alkylamines having 1 to 10 carbon atoms, cycloaliphatic amines having 4 to 8 carbon atoms, aromatic amines having 5 to 20 carbon atoms, linear or branched alkylphosphines having 1 to 10 carbon atoms, or linear or branched alkylphosphines having 1 to 10 carbon atoms.
Preferably, the complexing solution is selected from one or more of saturated or unsaturated fatty acids having 8 to 20 carbon atoms, linear or branched alkylamines having 1 to 5 carbon atoms, cycloaliphatic amines having 5 to 8 carbon atoms, aromatic amines having 5 to 10 carbon atoms, linear or branched alkylphosphines having 1 to 5 carbon atoms or linear or branched alkylphosphines having 1 to 5 carbon atoms.
Further, the saturated or unsaturated fatty acids include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid or oleic acid.
In step S1, the precursors required for the quantum dot nuclear reaction include a core layer cation precursor selected from group II element precursors and a core layer anion precursor selected from group VI element precursors.
In step S1, the shell cationic precursor is selected from group II element precursors and the shell anionic precursor is selected from group VI element precursors.
Further, the precursor of the group II element is at least one selected from a precursor of Zn element, a precursor of Cd element and a precursor of Hg element.
Further, the precursor of the group VI element is selected from at least one of a precursor of an S element, a precursor of a Se element, or a precursor of a Te element.
In some embodiments of the application, the quantum dot core and core shell quantum dot compounds comprise a combination of any one or more of the above CdS, cdSe, cdTe, znS, znSe, znTe, znO, hgS, hgSe, hgTe, cdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, cdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe, hgZnSTe.
Specifically, the precursor of Zn element includes: at least one of dimethyl zinc, diethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc oleate, zinc stearate, zinc undecylenate, zinc hydroxide, zinc peroxide, and the like, but not limited thereto.
Specifically, the precursor of the Cd element includes: at least one of cadmium oleate, cadmium butyrate, cadmium n-decanoate, cadmium caproate, cadmium caprylate, cadmium dodecanoate, cadmium myristate, cadmium palmitate, cadmium stearate, and the like, but is not limited thereto.
Specifically, the precursor of Hg element includes: at least one of mercury chloride, mercury bromide, mercury iodide, mercury acetate, mercury acetylacetonate, mercury oxide, mercury hydroxide, mercury carbonate, mercury nitrate, mercury perchlorate, mercury cyanide, or the like, but is not limited thereto.
Specifically, the precursor of S includes: at least one of hexanethiol, octanethiol, decanethiol, dodecyl mercaptan, hexadecyl mercaptan, mercaptopropyl silane, trioctylphosphine sulfide, tributylphosphine sulfide, triphenylphosphine sulfide, trioctylamine sulfide, tris (trimethylsilyl) sulfide, ammonium sulfide, sodium sulfide, or the like, but is not limited thereto.
Specifically, the precursor of Se includes: at least one of trioctylphosphine selenide, tributylphosphine selenide, triphenylphosphine selenide, and the like, but not limited thereto.
Specifically, the precursor of Te includes: at least one of tributylphosphine telluride, trioctylphosphine telluride, triphenylphosphine telluride, etc., but not limited thereto.
In some embodiments of the application, the quantum dots include CdSe/ZnSe core-shell quantum dots, cdZnSe/ZnSe core-shell quantum dots, cdSe/CdZnSe/ZnSe core-shell quantum dots, cdTe/CdZnTe/ZnSe core-shell quantum dots, cdTe/CdZnSe/ZnSe core-shell quantum dots, or CdTe/CdZnTe/ZnSe core-shell quantum dots, ceZnSe/CdZnSe/ZnSe/ZnS, cdZnSe/CdZnSe/CdZnS.
Correspondingly, the embodiment of the application also provides the quantum dot prepared by the preparation method.
In addition, the embodiment of the application also provides a light-emitting diode, which comprises an anode layer, a cathode layer and a light-emitting layer arranged between the anode layer and the cathode layer, wherein the material of the light-emitting layer comprises the quantum dot prepared by the preparation method or the quantum dot.
In some embodiments of the present application, there is provided a positive quantum dot light emitting diode, as shown in fig. 2, which includes, from bottom to top, an anode layer 1, a hole injection layer 2, a hole transport layer 3, a quantum dot light emitting layer 4, an electron transport layer 5, and a cathode layer 6; the material of the quantum dot light emitting layer 4 includes the quantum dot manufactured by the above manufacturing method or the above quantum dot.
Further, the thickness of the quantum dot light-emitting layer 4 may be 30 to 180nm, 50 to 150nm, or 70 to 100nm.
Further, the anode layer 1 is composed of a conductive material having a relatively high work function, and may be composed of a doped or undoped metal oxide such as Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), indium Tin Zinc Oxide (ITZO), indium Cerium Oxide (ICO), snO 2 、In 2 O 3 、Cd:ZnO、F:SnO 2 、In:SnO 2 、Ga:SnO 2 Or Aluminum Zinc Oxide (AZO), etc.; or it may be composed of a metal material including nickel (Ni), platinum (Pt), gold (Au), silver (Ag), iridium (Ir), or Carbon Nanotube (CNT) in addition to the above metal oxide.
Further, the thickness of the anode layer 1 may be 20 to 200nm, 50 to 150nm, or 70 to 100nm.
Further, the hole injection layer 2 includes poly (ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS), poly (9, 9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine) (TFB), polyarylamines, poly (N-vinylcarbazole), polyaniline, polypyrrole, N, N, N ', N' -tetrakis (4-methoxyphenyl) -benzidine (TPD), 4-bis [ N- (1-naphthyl) -N-phenyl-amino ] biphenyl (. Alpha. -NPD), 4 '-tris [ phenyl (m-tolyl) amino ] triphenylamine (m-MTDATA), 4',4 '-tris (N-carbazolyl) -triphenylamine (TCTA), 1-bis [ (di-4-tolylamino) phenylcyclohexane (TAPC), 4' -tris (diphenylamino) triphenylamine (TDATA) doped with tetrafluoro-tetracyano-quinone dimethane (F4-TCNQ), p-doped phthalocyanines (e.g., F4-TCNQ-doped zinc phthalocyanine (ZnPc)), F4-TCNQ doped N, N '-diphenyl-N, N' -bis (1-naphthyl) -1,1 '-biphenyl-4, 4' -diamine (alpha-NPD), hexaazabenzophenanthrene-capronitrile (HAT-CN).
Further, the thickness of the hole injection layer 2 may be 20 to 200nm, 50 to 150nm, or 70 to 100nm.
Further, the material of the hole transport layer 3 includes arylamines such as 4,4' -N, N ' -dicarbazolyl-biphenyl (CBP), N ' -diphenyl-N, N ' -bis (1-naphthyl) -1,1' -biphenyl-4, 4 "-diamine (α -NPD), N ' -diphenyl-N, N ' -bis (3-methylphenyl) - (1, 1' -biphenyl) -4,4' -diamine (TPD), N ' -bis (3-methylphenyl) -N, N ' -bis (phenyl) -spiro (spiro-TPD), N, N ' -bis (4- (N, N ' -diphenyl-amino) phenyl) -N, N ' -diphenyl benzidine (DNTPD), 4' -tris (N-carbazolyl) -triphenylamine (TCTA), tris (3-methylphenyl-phenylamino) -triphenylamine (m-MTDATA), poly [ (9, 9' -dioctylfluorene-2, 7-diyl) -co- (4, 4' - (N- (4-sec-butylphenyl) diphenylamine)) ] (TFB) and poly (4-butylphenyl-diphenylamine) (poly-TPD); polyaniline; polypyrrole; poly (p) phenylenevinylenes and derivatives thereof, such as poly (phenylenevinylene) (PPV), poly [ 2-methoxy-5- (2-ethylhexyloxy) -1, 4-phenylenevinylene ] (MEH-PPV) and poly [ 2-methoxy-5- (3 ',7' -dimethyloctyloxy) -1, 4-phenylenevinylene ] (MOMO-PPV); copper phthalocyanine; aromatic tertiary amines or polynuclear aromatic tertiary amines; 4,4 '-bis (p-carbazolyl) -1,1' -biphenyl compounds; n, N' -tetraarylbenzidine; PEDOT PSS and its derivatives; poly (N-vinylcarbazole) (PVK) and derivatives thereof; polymethacrylate and derivatives thereof; poly (9, 9-octylfluorene) and derivatives thereof; poly (spirofluorene) and derivatives thereof; n, N '-bis (naphthalen-1-yl) -N, N' -diphenyl benzidine (NPB); spiro NPB; and combinations thereof.
Further, the thickness of the hole transport layer 3 may be 30 to 180nm, 50 to 150nm, or 70 to 100nm.
Further, the electron transport layer 5 may be composed of an inorganic material and/or an organic material. When inorganic, it may be composed of an inorganic material selected from the group consisting of: metal/non-metal oxides (e.g., tiO) undoped or doped with Al, mg, in, li, ga, cd, cs or Cu 2 、ZnO、ZrO、SnO 2 、WO 3 、Ta 2 O 3 、HfO 3 、Al 2 O 3 、ZrSiO 4 、BaTiO 3 And BaZrO 3 ) The method comprises the steps of carrying out a first treatment on the surface of the Semiconductor particles undoped or doped with Al, mg, in, li, ga, cd, cs or Cu (e.g., cdS, znSe, and ZnS); nitrides, e.g. Si 3 N 4 The method comprises the steps of carrying out a first treatment on the surface of the And combinations thereof. In the case of an organic material, the organic material may be formed of an organic material such as an oxazole compound, an isoxazole compound, a triazole compound, an isothiazole compound, an oxadiazole compound, a thiadiazole compound, a perylene compound, or an aluminum complex.
Further, the thickness of the electron transport layer 5 may be 10 to 180nm, 50 to 150nm, or 70 to 100nm.
Further, the cathode layer 6 is composed of a conductive material having a relatively low work function, which may be Ca, ba, ca/Al, liF/Ca, liF/Al, baF 2 /Al、CsF/Al、CaCO 3 /Al、BaF 2 Ca/Al, al, mg, au Mg or Ag.
Further, the thickness of the cathode layer 6 may be 40 to 190nm, 50 to 150nm, or 70 to 100nm.
In some embodiments of the present application, a method for preparing a positive quantum dot light emitting diode includes sequentially forming a hole injection layer 2, a hole transport layer 3, a quantum dot light emitting layer 4, an electron transport layer 5, and a cathode layer 6 on an anode layer 1; the material of the quantum dot light emitting layer 4 includes the quantum dot manufactured by the above manufacturing method or the above quantum dot.
In specific implementation, the preparation method of the positive quantum dot light emitting diode comprises the following steps:
(1) Providing a substrate, and forming an anode layer 1 on the substrate;
(2) Forming a hole injection layer 2 on the anode layer 1;
(3) A hole transport layer 3 is formed on the hole injection layer 2.
(4) Depositing a quantum dot light-emitting layer 4 on the hole transport layer 3;
(5) Depositing an electron transport layer 5 on the quantum dot light emitting layer 4;
(6) A cathode layer 6 is formed on the electron transport layer 5.
Further, the substrate comprises a rigid, flexible substrate, specifically comprising glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, polyethersulfone, or combinations thereof.
The embodiment of the application also provides an inverted quantum dot light emitting diode, as shown in fig. 3, the materials of the quantum dot light emitting layer 13 comprise the quantum dot or the quantum dot prepared by the preparation method, wherein the cathode layer 11, the electron transport layer 12, the quantum dot light emitting layer 13, the hole transport layer 14, the hole injection layer 15 and the anode layer 16 are sequentially arranged from bottom to top.
Further, the thickness of the quantum dot light-emitting layer 13 may be 30 to 180nm, 50 to 150nm, or 70 to 100nm.
The materials of other layers are selected from the same positive quantum dot light emitting diode, and are not described herein.
In some embodiments of the present application, the method of fabricating the inverted quantum dot light emitting diode includes sequentially forming an electron transport layer 12, a quantum dot light emitting layer 13, a hole transport layer 14, a hole injection layer 15, and an anode layer 16 on a cathode layer 11; the material of the quantum dot light emitting layer 13 includes the quantum dot manufactured by the above manufacturing method or the above quantum dot.
In specific implementation, the preparation method of the inverted quantum dot light emitting diode comprises the following steps:
(1) Providing a substrate, and forming a cathode layer 11 on the substrate;
(2) Forming an electron transport layer 12 on the cathode layer 11;
(3) A quantum dot layer 13 is formed on the electron transport layer 12.
(4) Spin-coating a hole transport layer 14 on the quantum dot layer 13;
(5) Spin-coating a hole injection layer 15 on the hole transport layer 14;
(6) An anode layer 16 is formed on the hole injection layer 15.
The embodiment of the application also provides a display device which comprises the quantum dot light emitting diode.
The following description is made with reference to specific embodiments.
Embodiment 1,
The method for preparing the quantum dot light emitting diode of the embodiment comprises the following steps:
(1) Depositing an ITO anode layer with the thickness of 110nm on a glass substrate;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with thickness of 100nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 70nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/ZnSe/ZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 12mmol of zinc acetate, 12mL of oleic acid and 10mL of octadecene were added to a 100mL three-necked flask, and the reaction system was subjected to vacuum treatment at 100℃for 30min to remove water and oxygen. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After 50s of reaction at 300 ℃, 0.4mmol of cadmium oleate solution was added to the reaction system, and the reaction was carried out at 320 ℃ for 15min.
2) The argon flow is increased, then the temperature is raised to 360 ℃, and the non-coordination solution octadecene is removed. The reflux device for the reaction adopts a bent pipe angle of 60 degrees, the temperature of the bent pipe connected with the reaction is 100 ℃, and the temperature of the bent pipe disconnected with the reaction is 25 ℃.
3) Next, 1mmol of trioctylphosphine selenide and 0.4mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
4) Then, 0.5mmol of trioctylphosphine selenide was added to the reaction system, and reacted for 10 minutes.
5) Finally, 0.2mmol of trioctylphosphine sulfide was added to the reaction system and reacted for 10 minutes.
6) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/ZnSe/ZnS quantum dot, wherein the wavelength of a luminescence peak is 536nm, the peak width is 21nm, and the solution quantum yield of the quantum dot is 90%.
The quantum dot light emitting diode structure prepared in this embodiment is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/ZnSe/ZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Comparative example one,
The method for preparing the quantum dot light emitting diode of the first comparative example comprises the following steps:
(1) Depositing an ITO anode layer with the thickness of 110nm on a glass substrate;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with thickness of 100nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 70nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/ZnSe/ZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 12mmol of zinc acetate, 12mL of oleic acid and 10mL of octadecene were added to a 100mL three-necked flask, and the reaction system was subjected to vacuum treatment at 100℃for 30min to remove water and oxygen. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After 50s of reaction at 300 ℃, 0.4mmol of cadmium oleate solution was added to the reaction system, and the reaction was carried out at 320 ℃ for 15min. The reaction device adopts a straight reflux pipe, and the temperature of a reaction system is less than 360 ℃.
2) Next, 1mmol of trioctylphosphine selenide and 0.4mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
3) Then, 0.5mmol of trioctylphosphine selenide was added to the reaction system, and reacted for 10 minutes.
4) Finally, 0.2mmol of trioctylphosphine sulfide was added to the reaction system and reacted for 10 minutes.
5) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/ZnSe/ZnS quantum dot, wherein the wavelength of a luminescence peak is 535nm, the peak width is 21nm, and the solution quantum yield of the quantum dot is 62%.
The quantum dot light emitting diode structure prepared in this comparative example is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/ZnSe/ZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Embodiment II,
The method for preparing the quantum dot light emitting diode of the embodiment comprises the following steps:
(1) Depositing an ITO anode layer on a glass substrate, wherein the thickness of the ITO anode layer is 120nm;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with the thickness of 110nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 90nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/ZnSe/ZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 12mmol of zinc acetate, 12mL of oleic acid and 10mL of octadecene were added to a 100mL three-necked flask, and the reaction system was subjected to vacuum treatment at 100℃for 30min to remove water and oxygen. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After 50s of reaction at 300 ℃, 0.4mmol of cadmium oleate solution was added to the reaction system, and the reaction was carried out at 320 ℃ for 15min.
2) The argon flow is increased, then the temperature is raised to 360 ℃, and the non-coordination solution octadecene is removed. The reflux device for the reaction adopts a bent pipe angle of 60 degrees, the temperature of the bent pipe connected with the reaction is 100 ℃, and the temperature of the bent pipe disconnected with the reaction is 25 ℃.
3) Next, 1mmol of trioctylphosphine selenide and 0.5mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
4) Then, 0.5mmol of trioctylphosphine selenide was added to the reaction system, and reacted for 10 minutes.
5) Finally, 0.3mmol of trioctylphosphine sulfide was added to the reaction system and reacted for 10 minutes.
6) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/ZnSe/ZnS quantum dot, wherein the wavelength of a luminescence peak is 540nm, the peak width is 21nm, and the solution quantum yield of the quantum dot is 89%.
The quantum dot light emitting diode structure prepared in this embodiment is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/ZnSe/ZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Comparative example II,
The method for preparing the quantum dot light emitting diode of the second comparative example comprises the following steps:
(1) Depositing an ITO anode layer on a glass substrate, wherein the thickness of the ITO anode layer is 120nm;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with the thickness of 110nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 90nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/ZnSe/ZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 12mmol of zinc acetate, 12mL of oleic acid and 10mL of octadecene were added to a 100mL three-necked flask, and the reaction system was subjected to vacuum treatment at 100℃for 30min to remove water and oxygen. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After 50s of reaction at 300 ℃, 0.4mmol of cadmium oleate solution was added to the reaction system, and the reaction was carried out at 320 ℃ for 15min. The reaction device adopts a straight reflux pipe, and the temperature of a reaction system is less than 360 ℃.
2) Next, 1mmol of trioctylphosphine selenide and 0.5mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
3) Then, 0.5mmol of trioctylphosphine selenide was added to the reaction system, and reacted for 10 minutes.
4) Finally, 0.3mmol of trioctylphosphine sulfide was added to the reaction system and reacted for 10 minutes.
5) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/ZnSe/ZnS quantum dot, wherein the luminous peak wavelength is 539nm, the peak width is 21nm, and the solution quantum yield of the quantum dot is 58%.
The quantum dot light emitting diode structure prepared in this comparative example is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/ZnSe/ZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Third embodiment,
The method for preparing the quantum dot light emitting diode of the embodiment comprises the following steps:
(1) Depositing an ITO anode layer on a glass substrate, wherein the thickness of the ITO anode layer is 120nm;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with the thickness of 110nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 90nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/CdZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 5mmol of zinc acetate, 5mL of oleic acid and 25mL of octadecene were added to a 100mL three-necked flask, and the reaction system was subjected to vacuum treatment at 100℃for 30min to remove water and oxygen. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After reacting at 300℃for 60 seconds, a solution of 0.12mmol of cadmium oleate was added to the reaction system, and reacted at 320℃for 15 minutes.
2) The argon flow is increased, then the temperature is raised to 360 ℃, and the non-coordination solution octadecene is removed. The reflux device for the reaction adopts a bent pipe angle of 60 degrees, the temperature of the bent pipe connected with the reaction is 100 ℃, and the temperature of the bent pipe disconnected with the reaction is 25 ℃.
3) Next, 1mmol of trioctylphosphine selenide and 0.12mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
4) Then, 0.048mmol of trioctylphosphine selenide and 0.4mmol of trioctylphosphine sulfide were simultaneously added to the reaction system, and reacted for 10 minutes.
5) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/CdZnS quantum dot, wherein the wavelength of a luminescence peak is 475nm, the peak width is 16nm, and the solution quantum yield of the quantum dot is 85%.
The quantum dot light emitting diode structure prepared in this embodiment is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/CdZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Comparative example III,
The method for preparing the quantum dot light emitting diode of the third comparative example comprises the following steps:
(1) Depositing an ITO anode layer on a glass substrate, wherein the thickness of the ITO anode layer is 120nm;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with the thickness of 110nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 90nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/CdZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 5mmol of zinc acetate, 5mL of oleic acid and 25mL of octadecene were added to a 100mL three-necked flask, and the reaction system was subjected to vacuum treatment at 100℃for 30min to remove water and oxygen. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After reacting at 300℃for 60 seconds, a solution of 0.12mmol of cadmium oleate was added to the reaction system, and reacted at 320℃for 15 minutes. The reaction device adopts a straight reflux pipe, and the temperature of a reaction system is less than 360 ℃.
2) Next, 1mmol of trioctylphosphine selenide and 0.12mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
3) Then, 0.048mmol of trioctylphosphine selenide and 0.4mmol of trioctylphosphine sulfide were simultaneously added to the reaction system, and reacted for 10 minutes.
4) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/CdZnS quantum dot, wherein the wavelength of a luminescence peak is 473nm, the peak width is 18nm, and the solution quantum yield of the quantum dot is 51%.
The quantum dot light emitting diode structure prepared in this embodiment is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/CdZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Fourth embodiment,
The method for preparing the quantum dot light emitting diode of the embodiment comprises the following steps:
(1) Depositing an ITO anode layer with the thickness of 110nm on a glass substrate;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with thickness of 100nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 70nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/ZnSe/ZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 12mmol of zinc acetate, 12mL of oleic acid and 10mL of 1-eicosene were added to a 100mL three-necked flask, and the mixture was vacuum-treated at 100℃for 30min to remove water and oxygen in the reaction system. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After 50s of reaction at 300 ℃, 0.4mmol of cadmium oleate solution was added to the reaction system, and the reaction was carried out at 320 ℃ for 15min.
2) The argon flow is increased, then the temperature is raised to 360 ℃, and the non-coordination solution 1-eicosene is removed. The reflux device for the reaction adopts a bent pipe angle of 60 degrees, the temperature of the bent pipe connected with the reaction is 100 ℃, and the temperature of the bent pipe disconnected with the reaction is 25 ℃.
3) Next, 1mmol of trioctylphosphine selenide and 0.4mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
4) Then, 0.5mmol of trioctylphosphine selenide was added to the reaction system, and reacted for 10 minutes.
5) Finally, 0.2mmol of trioctylphosphine sulfide was added to the reaction system and reacted for 10 minutes.
6) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/ZnSe/ZnS quantum dot, wherein the wavelength of a luminescence peak is 538nm, the peak width is 22nm, and the solution quantum yield of the quantum dot is 88%.
The quantum dot light emitting diode structure prepared in this embodiment is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/ZnSe/ZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
Comparative example four,
The method for preparing the quantum dot light emitting diode of the fourth comparative example comprises the following steps:
(1) Depositing an ITO anode layer with the thickness of 110nm on a glass substrate;
(2) Depositing a hole injection layer PEDOT on the anode layer: PSS with thickness of 100nm;
(3) Depositing a hole transport layer TFB on the hole injection layer to a thickness of 70nm;
(4) Depositing quantum dot luminescent layers CdZnSe/CdZnSe/ZnSe/ZnS on the hole transport layer with the thickness of 30nm;
(5) Depositing a 70nm electron transport layer ZnO on the quantum dot luminescent layer;
(6) Depositing 60nm AG on the electron transport layer;
(7) After the device preparation is completed, the device is subjected to heat treatment at 120 ℃ for 15min, and then the device after the heat treatment is subjected to subsequent performance characterization.
The preparation method of the quantum dot material in the step (4) comprises the following steps:
1) 12mmol of zinc acetate, 12mL of oleic acid and 10mL of 1-eicosene were added to a 100mL three-necked flask, and the mixture was vacuum-treated at 100℃for 30min to remove water and oxygen in the reaction system. Then, the temperature was raised to 300℃under an argon atmosphere, and 1mmol of trioctylphosphine selenide was injected into the reaction. After 50s of reaction at 300 ℃, 0.4mmol of cadmium oleate solution was added to the reaction system, and the reaction was carried out at 320 ℃ for 15min. The reaction device adopts a straight reflux pipe, and the temperature of a reaction system is less than 360 ℃.
2) Next, 1mmol of trioctylphosphine selenide and 0.4mmol of cadmium oleate were simultaneously added to the reaction system, and reacted at 360℃for 30 minutes.
3) Then, 0.5mmol of trioctylphosphine selenide was added to the reaction system, and reacted for 10 minutes.
4) Finally, 0.2mmol of trioctylphosphine sulfide was added to the reaction system and reacted for 10 minutes.
5) After the reaction is finished, cleaning the reaction stock solution to finally obtain the CdZnSe/CdZnSe/ZnSe/ZnS quantum dot, wherein the wavelength of a luminescence peak is 534nm, the peak width is 24nm, and the solution quantum yield of the quantum dot is 56%.
The quantum dot light emitting diode structure prepared in this comparative example is: ITO anode layer/PEDOT: PSS hole injection layer/TFB hole transport layer/CdZnSe/CdZnSe/ZnSe/ZnS quantum dot luminescent layer/ZnO electron transport layer/Ag cathode layer.
The quantum dot light emitting diodes prepared in the above comparative examples one to four and examples one to four were subjected to performance test as follows:
(1) External quantum dot efficiency:
the ratio of electron-hole pairs injected into the quantum dots to the number of outgoing photons is shown in the unit, and is an important parameter for measuring the advantages and disadvantages of the electroluminescent device, and the quantum dots can be obtained by measuring the electron-hole pairs with an EQE optical test instrument. The specific calculation formula is as follows:
where ηe is the light outcoupling efficiency, ηr is the ratio of the number of carriers recombined to the number of carriers injected, χ is the ratio of the number of excitons generating photons to the total number of excitons, KR is the rate of the radiative process, and KNR is the rate of the non-radiative process.
Test conditions: the process is carried out at room temperature, and the air humidity is 30-60%.
(2) QLED device lifetime: the time required for the device to decrease in brightness to a certain proportion of the maximum brightness under constant current or voltage drive is defined as T95, and the lifetime is the measured lifetime. To shorten the test period, the device lifetime test is usually performed by accelerating the aging of the device under high brightness with reference to the OLED device test, and the lifetime under high brightness is obtained by fitting an extended exponential decay brightness decay fitting formula, for example: the lifetime counter at 1000nit is T951000nit. The specific calculation formula is as follows:
T95 in L T95 is the life at low brightness H For the actual life under high brightness, L H To accelerate the device to the highest brightness, L L For 1000nit, A is an acceleration factor, for OLED, the value is usually 1.6-2, and the experiment obtains the A value to be 1.7 by measuring the service lives of a plurality of groups of green QLED devices under rated brightness.
And (3) carrying out life test on the corresponding device by adopting a life test system, wherein the test conditions are as follows: the process is carried out at room temperature, and the air humidity is 30-60%.
The test results are shown in the following table:
as can be seen from the results in the table, the device lifetime and the external quantum dot efficiency of the examples are significantly improved compared with those of the comparative examples. In the embodiment, a high-temperature exhaust method is adopted to remove the non-coordination solution in the preparation process of the quantum dots, and the non-coordination solution is not removed in the preparation process of the quantum dots in the comparative example, so that the boiling point of a reaction system is improved after the non-coordination solution is removed, and a shell layer grows at a high temperature, thereby improving the luminous efficiency of the quantum dots and the performance of a device.
The application provides a quantum dot preparation method and a QLED device thereof. In the method for preparing the novel quantum dot, the defect that other solvents are additionally introduced in the existing growth process of the high Wen Keceng can be effectively avoided, byproducts are avoided or the growth environment of a shell layer is changed, the original growth environment of the quantum dot is kept, the crystallinity of the whole quantum dot is improved, the luminous efficiency of the quantum dot is improved, and a foundation is laid for the development of high-performance QLEDs.
The quantum dot, the preparation method thereof, the light emitting diode and the display device provided by the embodiment of the application are described in detail, and specific examples are applied to the description of the principle and the implementation mode of the application, and the description of the above examples is only used for helping to understand the method and the core idea of the application; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in light of the ideas of the present application, the present description should not be construed as limiting the present application.

Claims (14)

1. The preparation method of the quantum dot is characterized by comprising the following steps:
providing a mixed solution comprising a coordinating solution, a non-coordinating solution, and a quantum dot core;
removing a preset proportion of the non-coordinating solution;
providing a shell cation precursor and a shell anion precursor, and carrying out quantum dot shell growth;
wherein the coordinating solution has a boiling point higher than the non-coordinating solution.
2. The method of claim 1, wherein the non-coordinating solution has a boiling point of 200-320 ℃ and the coordinating solution has a boiling point of 320-400 ℃ at one atmosphere.
3. The method of claim 1, wherein the removing the non-coordinating solution comprises: vaporizing the non-coordinating solution under a first vacuum condition and/or a first temperature condition to thereby remove the non-coordinating solution.
4. The method of claim 3, wherein the vacuum degree is 10 under the first vacuum condition -4 ～10 -6 Torr, the temperature is 100-350 ℃; and/or, under the first temperature condition, the temperature is 320-380 ℃.
5. The method for preparing the quantum dot according to claim 1, wherein the concentration of the quantum dot core is 10-200 mg/mL based on the total volume of the mixed solution, and the volume ratio of the non-coordinating solution to the coordinating solution is 0.5-5: 1.
6. the method for preparing a quantum dot according to claim 1, wherein the preset proportion is 95% or more.
7. The method of claim 6, wherein the predetermined proportion is 100%.
8. The method of preparing a quantum dot according to claim 1, wherein the non-coordinating solution is selected from one or more of aliphatic hydrocarbons having 6 to 40 carbon atoms, aromatic hydrocarbons having 6 to 30 carbon atoms, nitrogen-containing heterocyclic compounds, or aromatic ethers having 12 to 22 carbon atoms; and/or
The complexing solution is selected from one or more of saturated or unsaturated fatty acids having 5 to 30 carbon atoms, linear or branched alkylamines having 1 to 10 carbon atoms, alicyclic amines having 4 to 8 carbon atoms, aromatic amines having 5 to 20 carbon atoms, linear or branched alkylphosphines having 1 to 10 carbon atoms, or linear or branched alkylphosphines having 1 to 10 carbon atoms; and/or
The precursor required for the quantum dot nuclear reaction comprises a nuclear layer cation precursor and a nuclear layer anion precursor, wherein the nuclear layer cation precursor is selected from precursors of II group elements, and the nuclear layer anion precursor is selected from precursors of VI group elements; and/or
The shell cationic precursor is selected from precursors of group II elements, and the shell anionic precursor is selected from precursors of group VI elements; and/or
The quantum dot core includes CdS, cdSe, cdTe, znS, znSe, znTe, hgS, hgSe, hgTe, cdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, cdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe, hgZnSTe; and/or
The quantum dot shell compounds include CdS, cdSe, cdTe, znS, znSe, znTe, hgS, hgSe, hgTe, cdSeS, cdSeTe, cdSTe, znSeS, znSeTe, znSTe, hgSeS, hgSeTe, hgSTe, cdZnS, cdZnSe, cdZnTe, cdHgS, cdHgSe, cdHgTe, hgZnS, hgZnSe, hgZnTe, cdZnSeS, cdZnSeTe, cdZnSTe, cdHgSeS, cdHgSeTe, cdHgSTe, hgZnSeS, hgZnSeTe, hgZnSTe.
9. The method of preparing a quantum dot according to claim 8, wherein the aliphatic hydrocarbon comprises hexadecane, octadecane, octadecene, eicosene or squalane, the aromatic hydrocarbon comprises phenyldodecane, phenyltetradecane or phenylhexadecane, the nitrogen-containing heterocyclic compound comprises pyridine, and the aromatic ether comprises phenyl ether or benzyl ether; and/or
The saturated or unsaturated fatty acids include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid or oleic acid; and/or
The precursor of the II group element is selected from at least one of a precursor of Zn element, a precursor of Cd element and a precursor of Hg element, and the precursor of the VI group element is selected from at least one of a precursor of S element, a precursor of Se element or a precursor of Te element.
10. The method of preparing a quantum dot according to claim 1, wherein the quantum dot comprises CdSe/ZnSe core-shell quantum dot, cdZnSe/ZnSe core-shell quantum dot, cdSe/CdZnSe/ZnSe core-shell quantum dot, cdTe/CdZnTe/ZnSe core-shell quantum dot, cdTe/CdZnSe/ZnSe core-shell quantum dot, or CdTe/CdZnTe/znte/ZnSe core-shell quantum dot, ceZnSe/CdZnSe/ZnSe/ZnS, cdZnSe/CdZnS.
11. A quantum dot produced by the production method according to any one of claims 1 to 10.
12. A light emitting diode comprising an anode layer, a cathode layer and a light emitting layer disposed between the anode layer and the cathode layer, wherein the material of the light emitting layer comprises the quantum dot produced by the production method according to any one of claims 1 to 10 or the quantum dot according to claim 11.
13. The light-emitting diode according to claim 12, wherein the thickness of the light-emitting layer is 30 to 180nm; and/or the material of the anode layer comprises ITO, IZO, ITZO, ICO, snO 2 、In 2 O 3 、CdZnO、FSnO 2 、InSnO 2 、GaSnO 2 One or more of AZO, ni, pt, au, ag, ir or CNT; and/or the cathode layer comprises Ca, ba, ca/Al, liF/Ca, liF/Al, baF 2 /Al、CsF/Al、CaCO 3 /Al、BaF 2 Ca/Al, al, mg, au Mg or Ag, one or more of Mg.
14. A display device comprising the light emitting diode according to claim 12 or claim 13.
CN202210323258.XA 2022-03-29 2022-03-29 Quantum dot, preparation method thereof, light emitting diode and display device Pending CN116925768A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024114078A1 (en) * 2022-11-30 2024-06-06 广东聚华新型显示研究院 Quantum dot preparation method, material screening method, and light-emitting device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024114078A1 (en) * 2022-11-30 2024-06-06 广东聚华新型显示研究院 Quantum dot preparation method, material screening method, and light-emitting device

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