Quantum dots and their preparation methods, thin films, and light-emitting devices

Abstract

This application discloses a quantum dot, its preparation method, a thin film, and a light-emitting device. The quantum dot preparation method includes: providing a nanocrystalline dispersion; adding a metal catalyst to the nanocrystalline dispersion; aging the dispersion to obtain a reaction solution; adding a purifying agent to the reaction solution for purification to obtain an alloy quantum dot core; dispersing the alloy quantum dot core in a second solvent; and then injecting a shell cation source and a shell anion source to form a shell on the surface of the alloy quantum dot core. The quantum dots prepared by the method described in this application have high luminescence purity.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a quantum dot, its preparation method, thin film, and light-emitting device. Background Technology

[0002] Quantum dots (QDs), also known as semiconductor nanocrystals, possess unique quantum size effects, macroscopic quantum tunneling effects, and surface effects, which give them outstanding physical properties, especially their optical properties, such as tunable spectrum, high luminescence intensity, high color purity, long fluorescence lifetime, and the ability to excite multicolor fluorescence from a single light source.

[0003] However, the purity of the emitted color of existing quantum dots is relatively low and needs to be further improved. Summary of the Invention

[0004] In view of this, this application provides a quantum dot, a method for preparing the same, a thin film, and a light-emitting device.

[0005] The embodiments of this application are implemented as follows: a method for preparing quantum dots includes the following steps:

[0006] A nanocrystalline dispersion is provided, the nanocrystalline dispersion comprising nanocrystalline particles and a first solvent;

[0007] A metal catalyst was added to the nanocrystalline dispersion for aging to obtain a reaction solution;

[0008] Purification agent was added to the reaction solution to obtain alloy quantum dot cores. The alloy quantum dot cores were then dispersed in a second solvent to obtain a core solution.

[0009] A shell cation source and a shell anion source are injected into the core solution to form a shell on the surface of the alloy quantum dot core, thereby obtaining a quantum dot.

[0010] Accordingly, this application also provides a quantum dot prepared by the aforementioned preparation method.

[0011] Accordingly, this application also provides a thin film comprising quantum dots prepared by the preparation method, or the thin film comprising the quantum dots.

[0012] Accordingly, this application also provides a light-emitting device, comprising an anode, a light-emitting layer and a cathode stacked sequentially, wherein the light-emitting layer comprises quantum dots prepared by the preparation method, or the light-emitting layer comprises the quantum dots, or the light-emitting layer is the thin film.

[0013] The quantum dots prepared by the method described in this application have high purity of luminescence color. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of a quantum dot preparation method provided in an embodiment of this application;

[0016] Figure 2 This is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this application.

[0017] Figure Labels

[0018] Light-emitting device 100; anode 10; light-emitting layer 20; cathode 30; electron transport layer 40; hole transport layer 50; hole injection layer 60. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0020] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0021] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] In this application, the term "on" forming another layer on a certain layer is a broad concept. It can mean that the formed other layer is adjacent to a certain layer, or it can mean that there are other spacer structures between the other layer and the certain layer. For example, when a second electrode is formed "on" a first charge carrier functional layer, the term "on" can mean that the formed second electrode is adjacent to the first charge carrier functional layer, or it can mean that there are other spacer structures between the second electrode and the first charge carrier functional layer, such as a light-emitting layer.

[0024] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, whichever applies. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0025] In this application, "substitution" means that the hydrogen atom in the substituent is replaced by the substituent.

[0026] In this application, when no linking site is specified in the group, it means that any linkable site in the group is selected as the linking site.

[0027] In this application, when the same substituent appears multiple times, it can be independently selected from different groups. If the general formula contains multiple R1s, then R1s can be independently selected from different groups.

[0028] In this application, "substituted or unsubstituted" means that the defined group may or may not be substituted. When the defined group is substituted, it should be understood that the defined group can be substituted by one or more substituents R, wherein R is selected from, but is not limited to: deuterium, cyano, isocyano, nitro or halogen, C1-30 alkyl, heterocyclic group containing 3-20 ring atoms, aromatic group containing 6-20 ring atoms, heteroaromatic group containing 5-20 ring atoms, -NR'R", silyl, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, halocarbamoyl, etc. Formyl, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl, and the above groups may be further substituted with substituents acceptable in the art; it is understood that R' and R" in -NR'R" are independently selected from, but not limited to: H, deuterium, cyano, isocyano, nitro or halogen, C1-10 alkyl, heterocyclic group containing 3-20 ring atoms, aromatic group containing 6-20 ring atoms, and heteroaromatic group containing 5-20 ring atoms.

[0029] In this application, "ring atom number" refers to the number of atoms in the ring itself of a structural compound (e.g., a monocyclic compound, a fused-ring compound, a cross-linked compound, a carbocyclic compound, or a heterocyclic compound) obtained by atomic bonding to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring-forming atoms. The same applies to the "ring atom number" described below unless otherwise specified. For example, a benzene ring has 6 ring atoms, a naphthalene ring has 10 ring atoms, and a thiophene group has 5 ring atoms.

[0030] In this application, "aryl or aromatic group" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl. For polycyclic rings, at least one is an aromatic ring system. For example, "substituted or unsubstituted aryl having 6 to 40 ring atoms" refers to an aryl containing 6 to 40 ring atoms, preferably a substituted or unsubstituted aryl having 6 to 30 ring atoms, more preferably a substituted or unsubstituted aryl having 6 to 18 ring atoms, and particularly preferably a substituted or unsubstituted aryl having 6 to 14 ring atoms, and optionally further substituted on the aryl group; suitable examples include, but are not limited to: phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthrene, fluoranyl, triphenylene, pyrene, perylene, tetraphenyl, fluorenyl, dinaphthylphenyl, acenaphthyl and their derivatives. Understandably, multiple aryl groups can also be interrupted by short non-aromatic units (e.g., <10% non-H atoms, such as C, N, or O atoms), specifically acenaphthene, fluorene, or 9,9-diarylfluorene, triarylamine, and diaryl ether systems should also be included in the definition of aryl.

[0031] In this application, "alkyl" can mean straight-chain, branched, or cyclic alkyl. The number of carbon atoms in an alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 10, or 1 to 6. Phrases containing this term, such as "C1-9 alkyl," refer to alkyl groups containing 1 to 9 carbon atoms, and each occurrence can independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, or C9 alkyl. Non-limiting examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, etc.

[0032] It should be noted that the thickness of the film in this application was measured using a step tester, and the average particle size in this application was measured using a transmission electron microscope (TEM).

[0033] Significant progress has been made in the solution-based synthesis of quantum dots. However, lattice defects generated during solution growth are still difficult to avoid. Multi-component alloys are considered an effective means to improve lattice fit and reduce lattice defects. In addition, shell coating can also effectively suppress the impact of quantum dot surface defects on optical properties.

[0034] However, for a long time, the growth of alloy layers has mainly involved the simultaneous reaction of different components. By controlling the reactivity of these components, a spontaneously formed crystalline state with a multi-atom distribution is achieved. For components with significantly different reactivity, it is difficult to improve the uniformity of component distribution after alloy formation. Metal ion-catalyzed multi-component quantum dot alloying offers a method to improve alloy uniformity, not only resulting in higher color purity and brightness of the quantum dots, but also enabling the homogeneous alloying of normally difficult-to-disperse alloy components, such as alloy quantum dots.

[0035] However, the surface of multi-component quantum dot alloys prepared by metal ion catalysis still contains a large number of defects. From the perspective of passivating defects and confining the wave function of the alloy quantum dots, an epitaxial shell is essential. However, due to the presence of the catalyst, the epitaxial shell can also transform into an alloy to some extent, which is detrimental to the wavelength control of the quantum dots and the structural design of the shell.

[0036] The technical solution of this application is as follows:

[0037] Firstly, please refer to Figure 1 This application provides a method for preparing quantum dots, comprising the following steps:

[0038] Step S11: Provide a nanocrystalline dispersion, wherein the nanocrystalline dispersion comprises nanocrystalline particles and a first solvent;

[0039] Step S12: Add a metal catalyst to the nanocrystalline dispersion for aging to obtain a reaction solution;

[0040] Step S13: Add a purifying agent to the reaction solution for purification to obtain alloy quantum dot cores. Disperse the alloy quantum dot cores in a second solvent to obtain a core solution.

[0041] Step S14: Inject a shell cation source and a shell anion source into the core solution to form a shell on the surface of the alloy quantum dot core to obtain a quantum dot.

[0042] In some embodiments, the purifying agent comprises organophosphorus compounds.

[0043] The reaction solution contains alloy quantum dot cores.

[0044] The quantum dot preparation method described in this application employs a catalyst to catalyze the ripening of nanocrystals to form an alloy quantum dot core with a more uniform composition distribution. Then, an organophosphorus compound is added to the reaction mixture to purify the alloy quantum dot core. This organophosphorus compound readily binds to the metal catalyst cations separated from the surface of the alloy quantum dot core, preventing the metal catalyst cations from remaining free in the system and then rebinding on the quantum dot surface after purification. This effectively removes the metal catalyst cations bound to the surface of the alloy quantum dot core, effectively avoiding the influence of the catalyst cations on subsequent shell growth and thus preventing low purity of the luminescence color of the prepared quantum dots. The quantum dot cores prepared by the method of this application have a more uniform composition distribution, a narrower half-width at half-maximum (WHM) of the emission peak, and higher luminescence purity. For example, the WHM of CdZnSe-based blue quantum dots can be reduced from the existing 16–22 nm to 14–18 nm; the WHM of CdZnSe-based green quantum dots can be reduced from the existing 20–25 nm to 16–20 nm; and the WHM of CdZnSe-based red quantum dots can be reduced from the existing 22–26 nm to 18–22 nm.

[0045] In step S11:

[0046] The nanocrystals include one or more of alloy nanocrystals and core-shell nanocrystals. The alloy nanocrystals are nanocrystals with a single structure. The core-shell nanocrystals include a nanocrystal core and a shell layer surrounding the nanocrystal core. The shell layer of the core-shell nanocrystals can be one or more layers; in at least one embodiment, the shell layer of the core-shell nanocrystals is one layer.

[0047] The alloy nanocrystals are made of one or more of the following: first group II-VI compounds and first group IV-VI compounds. The first group II-VI compounds include, but are not limited to, one or more of CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The first group IV-VI compounds may include, but are not limited to, one or more of SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe.

[0048] The materials of the nanocrystal core and the shell of the core-shell nanocrystal are each independently including, but not limited to, one or more of the second II-VI group compounds and the second IV-VI group compounds. The second group II-VI compound may include, but is not limited to, one or more of 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, and HgZnSTe. The second IV-VI compound may include, but is not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe.

[0049] In some embodiments, the average particle size of the alloy nanocrystals is 2 to 10 nm, for example, 2 nm, 3 nm, 5 nm, 6 nm, 8 nm, 10 nm, and any range between any two of the stated values.

[0050] In some embodiments, the average particle size of the nanocrystal nuclei is 2 to 10 nm, for example, 2 nm, 3 nm, 5 nm, 6 nm, 8 nm, 10 nm, and any range between any two of the stated values.

[0051] In some embodiments, the average thickness of the shell layer of the core-shell nanocrystal is 0.5 to 3 nm, for example, 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, and any range between any two of the stated values.

[0052] The first solvent includes, but is not limited to, one or more of the following: n-octane, isooctane, n-hexane, cyclohexane, ethyl acetate, benzene, toluene, chloroform, carbon tetrachloride, dichloromethane, dimethyl ether, 1-octadecene, and tetraethylene glycol dimethyl ether.

[0053] In some embodiments, the concentration of the nanocrystals in the nanocrystal dispersion is 5–100 mg / mL, for example, 5 mg / mL, 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, and any range between any two of the stated values.

[0054] In step S12:

[0055] The molecular formula of the metal catalyst is:

[0056] (R-COO) n M;

[0057] Where n is an integer from 1 to 2; M is selected from, but not limited to, Cu or Ag;

[0058] R is selected from substituted or unsubstituted C8 to C9. 30 Chain alkyl groups, substituted or unsubstituted C8-C 30 alkenyl, substituted or unsubstituted C8-C 30 alkynyl, substituted or unsubstituted C6-C 30 The aryl group, or a combination of the groups.

[0059] The substituents mentioned above are each independently selected from C1 to C1, each time they appear. 20 Alkyl, C1-C 20 Alkoxy, C2-C 20 alkenyl, C2-C 20 One or more of the following: alkynyl group, F, Cl, Br, I.

[0060] In some embodiments, R is selected from substituted or unsubstituted C. 10 ~C 20 Chain alkyl, substituted or unsubstituted C 10 ~C 20 alkenyl, substituted or unsubstituted C 10 ~C 20 alkynyl, substituted or unsubstituted C6-C20 The aryl group, or a combination of the groups.

[0061] Furthermore, in some embodiments, the R is selected from substituted or unsubstituted C. 10 ~C 18 Chain alkyl, substituted or unsubstituted C 10 ~C 18 alkenyl, substituted or unsubstituted C 10 ~C 18 alkynyl, substituted or unsubstituted C6-C 18 The aryl group, or a combination of the groups.

[0062] Furthermore, in some embodiments, the R is selected from substituted or unsubstituted C. 10 ~C 15 Chain alkyl, substituted or unsubstituted C 10 ~C 15 alkenyl, substituted or unsubstituted C 10 ~C 15 alkynyl, substituted or unsubstituted C 10 ~C 15 The aryl group, or a combination of the groups.

[0063] In some embodiments, the substituents are each independently selected from C1 to C1 each time they appear. 15 Alkyl, C1-C 15 Alkoxy, C2-C 15 alkenyl, C2-C 15 One or more of the following: alkynyl group, -F, -Cl, -Br, -I.

[0064] Furthermore, in some embodiments, the substituents are independently selected from C1 to C1 each time they appear. 10 Alkyl, C1-C 10 Alkoxy, C2-C 10 alkenyl, C2-C 10 One or more of the following: alkynyl group, -F, -Cl, -Br, -I.

[0065] Furthermore, in some embodiments, the substituents, each time they appear, are independently selected from one or more of C1-C5 alkyl, C1-C5 alkoxy, C2-C5 alkenyl, C2-C5 alkynyl, -F, -Cl, -Br, and -I.

[0066] As an example, in some embodiments, the metal catalyst includes, but is not limited to, one or more of copper compounds and silver compounds. The copper compounds include, but are not limited to, one or more of copper oleate, copper palmitate, copper stearate, copper acetylacetone, copper laurate, and copper isopalmitoate, and the silver compounds include, but are not limited to, one or more of silver oleate, silver palmitate, silver stearate, silver acetylacetone, silver laurate, and silver isopalmitoate.

[0067] In some embodiments, the molar ratio of the metal catalyst to the metal cations in the nanocrystals is 1:(5-200), for example, 1:5, 1:10, 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:160, 1:170, 1:180, 1:190, 1:200, and any range between any two of these ratios. Within this range, it is advantageous to prepare alloy quantum dot cores with good compositional uniformity.

[0068] In some embodiments, the curing temperature is 200–350°C, for example, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, and any range between any two of these values; the curing time is 1–120 min, for example, 1 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, and any range between any two of these values. Within this temperature range, it is beneficial to prepare alloy quantum dot cores with good compositional uniformity.

[0069] In step S13:

[0070] The organophosphorus compounds include, but are not limited to, C3-C4. 30 dialkylphosphine, C3-C 30 The organophosphorus compound is selected from one or more of the following: trialkylphosphine, diarylphosphine with 6 to 30 ring atoms, and triarylphosphine with 6 to 30 ring atoms. Further, the organophosphorus compound includes, but is not limited to, C3-C4. 25 dialkylphosphine, C3-C 25 The organophosphorus compound is selected from one or more of trialkylphosphine, diarylphosphine with 6 to 20 ring atoms, and triarylphosphine with 6 to 20 ring atoms. Further, the organophosphorus compound includes, but is not limited to, C3-C4 compounds. 20 dialkylphosphine, C3-C 25One or more of the following: trialkylphosphine, diarylphosphine with 6 to 15 ring atoms, and triarylphosphine with 6 to 20 ring atoms.

[0071] As an example, in some embodiments, C1 to C 20 Alkylphosphine includes, but is not limited to, one or more of dioctylphosphine, tri-n-octylphosphine, and tri-n-butylphosphine.

[0072] As an example, in some embodiments, the arylphosphine having 6 to 30 ring atoms includes, but is not limited to, one or more of diphenylphosphine and triphenylphosphine.

[0073] The volume ratio of the organophosphorus compound to the reaction solution is (0.01–0.2):1, for example, 0.01:1, 0.03:1, 0.05:1, 0.06:1, 0.08:1, 0.1:1, 0.12:1, 0.13:1, 0.15:1, 0.16:1, 0.18:1, 0.2:1, and any range between any two of these ratios. Within this range, the metal catalyst cations bound to the surface of the alloy quantum dot core can be removed sufficiently and effectively.

[0074] In some embodiments, the purification temperature is 280–350°C, for example, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, and any range between any two of these values; the purification time is 5–60 min, for example, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and any range between any two of these values. Within this temperature and time range, it is beneficial to sufficiently and effectively remove the metal catalyst cations bound to the surface of the alloy quantum dot core. Temperatures exceeding this purification temperature range may pose safety hazards.

[0075] In some embodiments, the purification process also includes microwave treatment. Microwave-assisted high-temperature purification facilitates the breaking of bonds between the metal catalyst cations and the anions on the surface of the alloy quantum dot core, and also allows the broken metal catalyst cations to preferentially bind to organophosphorus compounds, thereby being removed.

[0076] It should be noted that the simultaneous purification and microwave treatment means that purification and microwave treatment have a common processing time. Purification can begin first, microwave treatment can begin first, or both can begin simultaneously, as long as there is a common processing time. In some embodiments, the common processing time for purification and microwave treatment is 5–60 minutes, for example, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and any range between these values. Within this temperature and time range, it is beneficial to sufficiently and effectively remove the metal catalyst cations bound to the surface of the alloy quantum dot core.

[0077] In some embodiments, the wavelength of the microwaves used in the microwave treatment is 0.1–1000 mm, for example, 0.1 mm, 10 mm, 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm, 800 mm, 900 mm, 1000 mm, and any range between any two of these values; the frequency of the microwaves used in the microwave treatment is 0.3–3000 GHz, for example, 0.3 GHz, 0.5 GHz, 1 GHz, 50 GHz, 100 GHz, 500 GHz, 1500 GHz, 2000 GHz, 2500 GHz, 3000 GHz, and any range between any two of these values. Within these ranges, it is more conducive to the breaking of bonds formed between the metal catalyst cations and the anions on the surface of the alloy quantum dot core, and it is also more conducive to the preferential binding of the broken metal catalyst cations to organophosphorus compounds, thereby more effectively removing the metal catalyst cations.

[0078] In some embodiments, the wavelength of the microwaves used in the microwave treatment is 0.1–100 mm, and the frequency of the microwaves used in the microwave treatment is 2000 MHz–3000 GHz. Within this range, it is more conducive to the breaking of bonds formed between metal catalyst cations and anions on the surface of alloy quantum dot cores, and it is also more conducive to the preferential binding of the broken metal catalyst cations to organophosphorus compounds, thereby enabling more effective removal of metal catalyst cations.

[0079] In some embodiments, the second solvent includes, but is not limited to, one or more of n-octane, isooctane, n-hexane, cyclohexane, ethyl acetate, benzene, toluene, chloroform, carbon tetrachloride, dichloromethane, dimethyl ether, 1-octadecene, and tetraethylene glycol dimethyl ether.

[0080] In some embodiments, the concentration of the alloy quantum dot nuclei in the nucleus solution is 5–100 mg / mL, for example, 5 mg / mL, 10 mg / mL, 20 mg / mL, 30 mg / mL, 40 mg / mL, 50 mg / mL, 60 mg / mL, 70 mg / mL, 80 mg / mL, 90 mg / mL, 100 mg / mL, and any range between any two of the stated values.

[0081] In step S14:

[0082] In some embodiments, after injecting a shell cation source and a shell anion source into the core solution to form a shell on the surface of the alloy quantum dot core, the step is further repeated n times, where n is an integer greater than or equal to 1, so that a quantum dot with n+1 shells can be obtained.

[0083] The shell cation source includes, but is not limited to, one or more of zinc compounds, cadmium compounds, silver compounds, indium compounds, mercury compounds, tin compounds, and lead compounds. The zinc compound may be selected from, but is not limited to, one or more of zinc acetate, zinc palmitate, zinc stearate, zinc chloride, zinc bromide, zinc oxide, zinc nitrate, and zinc sulfate. The cadmium compound may be selected from, but is not limited to, one or more of chromium acetate, cadmium oxide, cadmium oleate, cadmium chloride, cadmium bromide, cadmium sulfate, and chromium nitrate. The silver compound may be selected from, but is not limited to, one or more of silver acetate, silver oxide, silver formate, silver acetate, and silver nitrate. The indium compound may be selected from, but is not limited to, one or more of indium acetate, indium nitrate, indium sulfate, indium chloride, indium bromide, indium sulfide, and indium oxide. The mercury compound may be selected from, but is not limited to, one or more of mercuric chloride, mercuric bromide, mercuric oxide, mercuric nitrate, and mercuric sulfate. The tin compound may be selected from, but is not limited to, tin acetate, tin palmitate, tin stearate, tin chloride, tin bromide, tin oxide, tin nitrate, and tin sulfate. The lead compound may be selected from, but is not limited to, one or more of lead acetate, lead palmitate, lead stearate, lead chloride, lead bromide, lead oxide, lead nitrate, and lead sulfate.

[0084] In some embodiments, the shell anion source includes, but is not limited to, at least one of sulfur powder, selenium powder, and tellurium powder.

[0085] In some embodiments, the molar ratio of the shell cation source and the shell anion source is (1 to 10):1, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and the range between any two of the ratios.

[0086] In some embodiments, the average particle size of the quantum dots is 2 to 20 nm, for example, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, and any range between any two of the stated values.

[0087] The quantum dot is a core-shell structured quantum dot. The core-shell structured quantum dot includes one or more shell layers.

[0088] The core-shell structured quantum dots are made of, but are not limited to, one or more of Group II-VI and Group IV-VI compounds. The Group II-VI compounds may include, but are not limited to, one or more of CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe. The Group IV-VI compounds may include, but are not limited to, one or more of SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe.

[0089] The shell material of the core-shell structured quantum dots may be one or more of group II-VI compounds and group IV-VI compounds, respectively. The group IV-VI compounds may be one or more of 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, and HgZnSTe. The fourth group IV-VI compound may include, but is not limited to, one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe.

[0090] In some embodiments, the surface of the quantum dot further includes organic ligands, including but not limited to substituted or unsubstituted C6-C6 ligands. 24 Fatty acids, substituted or unsubstituted C6-C 24 Fatty amines, substituted or unsubstituted C6-C 24 Aliphatic thiols, substituted or unsubstituted C6-C6 thiols 24 Aliphatic sulfides, substituted or unsubstituted C6-C 24 Aliphatic phosphine, substituted or unsubstituted C6-C 24 Aliphatic phosphine oxides, substituted or unsubstituted C8-C8 phosphine oxides 20 Aliphatic phosphates, substituted or unsubstituted C6-C6 phosphates 24 Aliphatic phosphates, substituted or unsubstituted C6-C6 phosphates 24 Aliphatic phosphorous acid and substituted or unsubstituted C6-C6 phosphorus 24 At least one of the fatty phosphites, wherein the substituent is selected from at least one of C1-C6 alkyl, C1-C6 alkoxy and halogen.

[0091] In some embodiments, the substituted or unsubstituted C6-C 24 Fatty acids include at least one of the following: decanoic acid, undecenoic acid, tetradecanoic acid, oleic acid, linoleic acid, and stearic acid.

[0092] In some embodiments, the substituted or unsubstituted C6-C 24 Aliphatic thiols include at least one of octylthiol, dodecylthiol, and octadecylthiol.

[0093] In some embodiments, the substituted or unsubstituted C6-C 24 Fatty amines include at least one of oleylamine, octadecylamine, octylamine, dioctylamine, and trioctylamine.

[0094] In some embodiments, the substituted or unsubstituted C6-C 24 Aliphatic phosphines include trioctylphosphine.

[0095] In some embodiments, the substituted or unsubstituted C6-C 24 Aliphatic phosphine oxides include trioctylphosphine oxides.

[0096] Secondly, embodiments of this application also provide a quantum dot, which is prepared by the preparation method described above.

[0097] The quantum dots described in this application have good uniformity of nuclear component distribution, high luminescence purity, and narrow emission peak half-width.

[0098] Thirdly, this application also provides a quantum dot ink, which includes the quantum dots and the third solvent described above.

[0099] The third solvent includes, but is not limited to, one or more of the following: n-octane, isooctane, n-hexane, cyclohexane, ethyl acetate, benzene, toluene, chloroform, carbon tetrachloride, dichloromethane, dimethyl ether, and tetraethylene glycol dimethyl ether.

[0100] In some embodiments, the concentration of the composite material in the quantum dot ink is 8–50 mg / mL, for example, 8 mg / mL, 10 mg / mL, 15 mg / mL, 20 mg / mL, 25 mg / mL, 30 mg / mL, 35 mg / mL, 40 mg / mL, etc.

[0101] 45 mg / mL, 50 mg / mL, and the range between any two of the stated values, etc.

[0102] Fourthly, embodiments of this application also provide a thin film, the material of which includes the quantum dots described above.

[0103] Fifthly, please refer to 2. This application provides a light-emitting device 100, including an anode 10, a light-emitting layer 20, and a cathode 30 stacked sequentially. The light-emitting layer 20 includes the quantum dots described above.

[0104] In some embodiments, the light-emitting device 100 further includes an electron transport layer 40 located between the light-emitting layer 20 and the cathode 30.

[0105] In some embodiments, the light-emitting device 100 further includes a hole transport layer 50 located between the anode 10 and the light-emitting layer 20.

[0106] In some embodiments, the light-emitting device 100 further includes a hole injection layer 60 located between the anode 10 and the hole transport layer 50.

[0107] The anode 10 and the cathode 30 are anodes and cathodes known in the art for use in light-emitting devices. For example, they can be independently, but are not limited to, doped metal oxide particle electrodes, composite electrodes, graphene electrodes, carbon nanotube electrodes, elemental metal electrodes, or alloy electrodes. The material of the doped metal oxide particle electrode can be, but is not limited to, one or more of indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium-doped zinc oxide (IZO), magnesium-doped zinc oxide (MZO), and aluminum-doped magnesium oxide (AMO). The composite electrode is a composite electrode in which a metal is sandwiched between doped or undoped transparent metal oxide particles, such as AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, ZnS / Al / ZnS, etc., where " / " indicates a stacked structure. For example, AZO / Ag / AZO represents a composite electrode comprising sequentially stacked AZO, Ag, and AZO layers. The material of the elemental metal electrode may include, but is not limited to, one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba.

[0108] The material of the electron transport layer 40 is a material known in the art for use in electron transport layers, such as one or more selected from, but not limited to, inorganic and organic electron transport materials. The inorganic electron transport material includes, but is not limited to, one or more of the following: first doped metal oxide particles, first undoped metal oxide particles, IIB-VIA group semiconductor materials, IIIA-VA group semiconductor materials, and IB-IIIA-VIA group semiconductor materials. The material of the first undoped metal oxide particles includes, but is not limited to, one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxide in the first doped metal oxide particles includes, but is not limited to, one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3. The doping element in the first doped metal oxide particles includes, but is not limited to, one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga. The IIB-VIA group semiconductor materials include, but are not limited to, one or more of ZnS, ZnSe, and CdS. The IIIA-VA group semiconductor materials include, but are not limited to, one or more of InP and GaP. The IB-IIIA-VIA group semiconductor materials include, but are not limited to, one or more of CuInS and CuGaS.The organic electron transport materials include diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide (TSPO1), 1,3,5-tris((3-pyridyl)-3-phenyl)benzene (TmPyPB), 2-(4-biphenyl)-5-phenyloxadiazole (PBD), bis(10-hydroxybenzo[h]quinoline)beryllium (Bebq2) (CAS: 148896-39-3), and 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole (T AZ), 2,7-bis(diphenyloxyphosphino)-9,9'-spirobis[fluorene] (SPPO13), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)phenyl (TPBI), 4,6-bis(3,5-di(3-pyridinylphenyl)-2-methylpyrimidine (B3PYMPM), 4,7-diphenyl-1,10-phenanthroline (BPhen), 2-(4'-tert-butylphenyl)-5-(4'-biphenyl)-1,3,4-oxadiazole, 2,9-dimethyl-4,7 -Diphenyl-1,10-o-phenanthroline, 4,7-diphenyl-1,10-o-phenanthroline, bis(2-methyl-8-hydroxyquinoline-N1,O8)-1,1'-biphenyl-4-hydroxy)aluminum, 8-hydroxyquinoline aluminum (Alq3), 2,7-bis(diphenyloxyphosphino)-9,9'-spirobis[fluorene], poly[9,9-dioctylfluorene-9,9-bis(N,N-dimethylaminopropyl)fluorene], 9,9-bis[3'-(N,N-dimethylamino)propyl-2,7-fluorene]-alternating-2, One or more of the following: 7-(9,9-dioctylfluorene), 1,3-bis[5-(4-tert-butylphenyl)-2-[1,3,4]oxadiazolyl]benzene (OXD-7), 3',3'",3'""-(1,3,5-triazine-2,4,6-triyl)-tris(([1,1'-biphenyl]-3-carboxynitrile))(CNT2T), and 2,4,6-tris[3-(diphenylphosphoxy)phenyl]-1,3,5-triazole (POT2T, CAS No.: 1646906-26-4).

[0109] The material of the hole transport layer 50 can also be any material known in the art for hole transport layers, such as, but not limited to, one or more of inorganic hole transport materials and organic hole transport materials. The inorganic hole transport material includes, but is not limited to, one or more of second-doped metal oxide particles, second-undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides. The metal oxides in the second-doped metal oxide particles and the metal oxides in the second-undoped metal oxide particles each independently include, but are not limited to, one or more of MoO3, WO3, NiO, CrO3, CuO, Cu2O, and V2O5. The doping elements in the second-doped metal oxide particles include, but are not limited to, one or more of Mo, W, Ni, Cr, Cu, and V. The metal sulfides include, but are not limited to, one or more of CuS, MoS3, and WS3. The metal selenides include, but are not limited to, one or more of MoSe3 and WSe3. The metal nitrides include, but are not limited to, p-type gallium nitride.The organic hole transport materials include, but are not limited to, 4,4'-N,N'-dicarbazolyl-biphenyl (CBP), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine (α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD), poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)biphenylamine) (Poly-TPD), N,N'- Bis(3-methylphenyl)-N,N'-bis(phenyl)-spiro(spiro-TPD), N,N'-bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTPD), 4,4',4'-tris(N-carbazolyl)-triphenylamine (TCTA), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), poly[(9,9'-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))](TFB), poly(N-vinylcarbazole)(PVK) ) and its derivatives, N,N'-di(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine (NPB), spiroNPB, poly(phenylenevinylene) (PPV), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MOMO-PPV), 2,2',7,7'-tetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (spiro-omeT) AD), 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC), 1,3-bis(carbazole-9-yl)benzene (MCP), polyaniline, polypyrrole, poly(p-)phenylenevinylene, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazole)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, and one or more of C60.

[0110] The material of the hole injection layer 60 can be any material known in the art for hole injection layers, such as, but not limited to, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzphenanthrene (HAT-CN), PEDOT, PEDOT:PSS, a derivative of PEDOT:PSS doped with s-MoO3 (PEDOT:PSS:s-MoO3), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), tetracyanoquinone dimethyl ether (F4-TCQN), copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

[0111] In some embodiments, the thickness of the anode 10 is 10–200 nm; the thickness of the light-emitting layer 20 is 5–100 nm; the thickness of the cathode 30 is 30–100 nm; the thickness of the electron transport layer 40 is 20–60 nm; the thickness of the hole transport layer 50 is 20–100 nm; and the thickness of the hole injection layer 60 is 20–100 nm.

[0112] It is understood that the light-emitting device 100 may also be provided with some functional layers that are conventionally used in light-emitting devices and help to improve the performance of the light-emitting device, such as electron blocking layer, hole blocking layer, electron injection layer, interface modification layer, etc.

[0113] It is understood that the materials of each layer of the light-emitting device 100 can be adjusted according to the light-emitting requirements of the light-emitting device 100.

[0114] In some embodiments, the light-emitting device 100 further includes a substrate disposed on the side of the anode 10 away from the light-emitting layer 20, or the substrate disposed on the side of the cathode 30 away from the light-emitting layer 20.

[0115] The substrate can be a rigid substrate or a flexible substrate. In some embodiments, the substrate material may include, but is not limited to, one or more of glass, silicon wafer, polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polyamide, and polyethersulfone.

[0116] It is understood that the light-emitting device 100 can be a normally positioned light-emitting device or an inverted light-emitting device. The light-emitting device 100 can be a quantum dot light-emitting device or an organic light-emitting device.

[0117] Sixthly, embodiments of this application also provide a display device, the display device including the light-emitting device 100.

[0118] The display device can be any electronic product with display function, including but not limited to smartphones, tablets, laptops, digital cameras, digital camcorders, smart wearable devices, smart weighing scales, in-vehicle displays, televisions, or e-book readers. Among them, smart wearable devices can be, for example, smart bracelets, smartwatches, virtual reality (VR) headsets, etc.

[0119] The present application will be specifically described below through specific embodiments. The following embodiments are only some embodiments of the present application and are not intended to limit the present application.

[0120] Ink Example 1

[0121] Step 1: Provide an octane dispersion of CdSe / ZnSe core-shell nanocrystals, wherein the core-shell nanocrystals have a full width at half maximum (FWHM) of 25 nm, an average particle size of 7 nm, a molar amount of 1 mmol, and a dispersion volume of 30 mL; heat the core-shell nanocrystal dispersion to 300 °C under an inert atmosphere, then add 0.01 mmol of copper oleate, and ripen for 10 minutes to obtain a reaction solution, wherein the reaction solution includes CdZnS alloy quantum dot cores with an average particle size of 7 nm;

[0122] Step 2: Then add 3 mL of tri-n-octylphosphine, mix well, purify at 315℃ for 30 min, and evenly dispense into 3 centrifuge tubes. Add 20 mL of ethyl acetate and 15 mL of ethanol to each centrifuge tube, shake well, and centrifuge. Disperse the precipitate with 5 mL of n-hexane, add 10 mL of ethanol again to precipitate, centrifuge, and disperse the precipitate with 1-octadecene to obtain the nucleus solution.

[0123] Step 3: Add 5 mL of oleic acid and 15 mL of 1-octadecene to the above nuclear solution, degas the solution, exhaust the gas with argon, and heat the solution to 300°C. Simultaneously and slowly inject 2 mmol of zinc oleate precursor (0.2 M) and 1 mmol of Se-TOP precursor (0.5 M) into the reaction system while stirring continuously. The injection is completed in 30 min to obtain the quantum dot stock solution, which includes CdZnSe / ZnSe quantum dots.

[0124] Step 4: Cool the above quantum dot stock solution to room temperature, divide it into 4 centrifuge tubes, add 20 mL of ethyl acetate and 15 mL of ethanol to each centrifuge tube, shake well, and centrifuge. Disperse the precipitate with 5 mL of n-hexane, add 10 mL of ethanol again to precipitate, centrifuge again, disperse the precipitate with 3 mL of n-hexane, repeat twice to obtain quantum dot ink.

[0125] Ink Example 2

[0126] Step 1: Provide an octane dispersion of CdZnS alloy nanocrystals (alloy nanocrystals), wherein the emission peak of the alloy nanocrystals is 470 nm, the molar amount of a single-structure nanocrystal is 1 mmol, and the volume of the dispersion is 30 mL; heat the core-shell nanocrystal dispersion to 300 °C under an inert atmosphere, then add 0.1 mmol of copper oleate, and ripen for 10 minutes to obtain a reaction solution, wherein the reaction solution includes CdZnS alloy quantum dot cores with an average particle size of 5 nm;

[0127] Step 2: Then add 6 mL of tri-n-octylphosphine, mix well, purify at 315℃ for 30 min, and evenly dispense into 3 centrifuge tubes. Add 20 mL of ethyl acetate and 15 mL of ethanol to each centrifuge tube, shake well, and centrifuge. Disperse the precipitate with 5 mL of n-hexane, add 10 mL of ethanol again to precipitate, centrifuge again, and disperse the precipitate with 1-octadecene to obtain the nucleus solution.

[0128] Step 3: Add 5 mL of oleic acid and 15 mL of 1-octadecene to the above nuclear solution, degas the solution, exhaust the gas with argon, and heat the solution to 300°C. Simultaneously and slowly inject 2 mmol of zinc oleate precursor (0.2 M), 0.3 mmol of cadmium oleate precursor (0.3 M), and 1 mmol of S-TOP precursor (0.5 M) into the reaction system while continuously stirring for 30 min to obtain the quantum dot stock solution, which includes CdZnSe / ZnSe quantum dots.

[0129] Step 4: Cool the above quantum dot stock solution to room temperature, divide it into 4 centrifuge tubes, add 20 mL of ethyl acetate and 15 mL of ethanol to each centrifuge tube, shake well, and centrifuge. Disperse the precipitate with 5 mL of n-hexane, add 10 mL of ethanol again to precipitate, centrifuge again, disperse the precipitate with 3 mL of n-hexane, repeat twice to obtain quantum dot ink.

[0130] Ink Example 3

[0131] This embodiment is basically the same as ink embodiment 1, except that the amount of copper oleate used in this embodiment is 0.2 mmol.

[0132] Ink Example 4

[0133] This embodiment is basically the same as ink embodiment 1, except that the amount of copper oleate used in this embodiment is 0.005 mmol.

[0134] Ink Example 5

[0135] This embodiment is basically the same as ink embodiment 1, except that in this embodiment, the amount of tri-n-octylphosphine used is 0.3 mL.

[0136] Ink Example 6

[0137] This embodiment is basically the same as ink embodiment 1, except that in this embodiment, the amount of tri-n-octylphosphine used is 6 mL.

[0138] Ink Example 7

[0139] This embodiment is basically the same as ink embodiment 1, except that the purification temperature in this embodiment is 280°C.

[0140] Ink Example 8

[0141] This embodiment is basically the same as ink embodiment 1, except that the purification temperature in this embodiment is 350°C.

[0142] Ink Example 9

[0143] This embodiment is basically the same as ink embodiment 1, except that tri-n-butylphosphine is used in this embodiment to replace tri-n-octylphosphine in ink embodiment 1.

[0144] Ink Example 10

[0145] This embodiment is basically the same as ink embodiment 1, except that diphenylphosphine is used in this embodiment to replace tri-n-octylphosphine in ink embodiment 1.

[0146] Ink Example 11

[0147] This embodiment is basically the same as ink embodiment 1, except that silver oleate is used in this embodiment to replace copper oleate in embodiment 1.

[0148] Ink Example 12

[0149] This embodiment is basically the same as ink embodiment 1, except that CdS / ZnS core-shell nanocrystals are used to replace CdSe / ZnSe core-shell nanocrystals in ink embodiment 1.

[0150] Ink Example 13

[0151] This embodiment is basically the same as ink embodiment 1, except that cadmium oleate is used in this embodiment to replace zinc oleate in ink embodiment 1.

[0152] Ink Example 14

[0153] This embodiment is basically the same as ink embodiment 1, except that in step 2 of this embodiment, microwave treatment is also included during purification. The wavelength of the microwave used in the microwave treatment is 500 mm, and the frequency of the microwave used in the microwave treatment is 1500 GHz.

[0154] Ink Example 15

[0155] This embodiment is basically the same as ink embodiment 14, except that in step 2 of this embodiment, microwave treatment is also included during purification, and the wavelength of the microwave used in the microwave treatment is 0.1 mm.

[0156] Ink Example 16

[0157] This embodiment is basically the same as ink embodiment 14, except that in step 2 of this embodiment, microwave treatment is also included during purification, and the wavelength of the microwave used in the microwave treatment is 100mm.

[0158] Ink Example 17

[0159] This embodiment is basically the same as ink embodiment 14, except that in step 2 of this embodiment, microwave treatment is also included during purification, and the frequency of the microwave used in the microwave treatment is 0.3 GHz.

[0160] Ink Example 18

[0161] This embodiment is basically the same as ink embodiment 14, except that in step 2 of this embodiment, microwave treatment is also included during purification, and the microwave frequency used in the microwave treatment is 3000 GHz.

[0162] Ink Comparison Example 1

[0163] This comparative example is basically the same as ink example 1, except that this comparative example does not include step 2 in ink example 1.

[0164] Ink Comparison Example 2

[0165] This comparative example is basically the same as ink example 1, except that tri-n-octylphosphine was not used in step 2 of this comparative example.

[0166] Ink Comparison Example 3

[0167] This comparative example is basically the same as ink example 1, except that the purification temperature in step 2 of this comparative example is 270°C.

[0168] Ink Comparison Example 4

[0169] This comparative example is basically the same as ink example 2, except that this comparative example does not include step 2 in ink example 2.

[0170] Ink Comparison Example 5

[0171] This comparative example is basically the same as ink example 2, except that tri-n-octylphosphine was not used in step 2 of this comparative example.

[0172] Ink Comparison Example 6

[0173] This comparative example is basically the same as ink example 2, except that the purification temperature in step 2 of this comparative example is 270°C.

[0174] The nanocrystals, alloy quantum dot cores, and quantum dots in ink Examples 1-18 and Comparative Examples 1-6 were subjected to spectral tests respectively. The emission peak positions and full width at half maximum (FWHM) of the nanocrystals and quantum dots were tested, and the test results are shown in Table 1.

[0175] Spectroscopic measurements were performed using a Hitachi F-7000 fluorescence spectrophotometer.

[0176] Table 1:

[0177]

[0178]

[0179] As shown in Table 1:

[0180] In ink Examples 1-18 and ink Comparative Examples 1-6, compared with nanocrystals, the emission peak position of the alloy quantum dot core is smaller and the half-width is narrower. It can be seen that the metal catalyst can reduce the wavelength and narrow the half-width. The reason may be that the use of the metal catalyst can make the metal ions in the quantum dot core more uniformly dispersed.

[0181] The emission peak of the quantum dots in ink Comparative Example 1 is smaller than that of the quantum dot nucleus of the small alloy. The emission peak of the quantum dots in ink Examples 1, 3-18 is smaller than that of their alloy quantum dots. The reason may be that in ink Comparative Example 1, there are residual metal catalyst cations in the system during the preparation of the epitaxial shell ZnSe. This causes Cd in the core to diffuse further into the shell during the growth of the epitaxial ZnSe shell, resulting in a further decrease in wavelength. In contrast, in ink Examples 1, 3-18, there are no residual metal catalyst cations or the residual amount is extremely small in the system during the preparation of the epitaxial shell. Compared with the shell in ink Comparative Example 1, the shell of ink Example 1 has a weaker ability to bind the wave function of the blue CdZnSe nucleus, resulting in a longer wavelength.

[0182] Compared to the quantum dots in ink comparative examples 2-3, the quantum dot emission peak position of ink example 1 is slightly longer and the half-peak width is narrower. This may be because ink comparative examples 2-3 cannot effectively remove the residual metal catalyst cations in the system.

[0183] Compared to the quantum dots in ink comparative examples 1-3, the quantum dots in ink examples 1, 3-18 have a narrower half-width and higher color purity.

[0184] The emission peak position of the quantum dots in ink Comparative Example 2 is significantly larger than that of the quantum dot nucleus of the alloy, while the emission peak position of the quantum dots in ink Example 2 is smaller than that of its alloy quantum dots. The reason may be that in ink Comparative Example 1, when preparing the epitaxial shell CdZnS, there are residual metal catalyst cations in the system, and the Cd in the shell penetrates into the core, resulting in a significant increase in wavelength. In ink Example 2, when preparing the epitaxial shell, there are no residual metal catalyst cations or the residual amount is extremely small. Compared with the shell in ink Comparative Example 2, the shell of ink Example 2 has a weaker ability to bind the wavefunction of the blue CdZnSe nucleus, and the wavelength is slightly red-shifted.

[0185] Compared to the quantum dots in ink comparative examples 5-6, the quantum dot emission peak of ink example 2 is slightly shorter and the half-peak width is narrower. This may be because ink comparative examples 5-6 cannot effectively remove the residual metal catalyst cations in the system.

[0186] Compared to the quantum dots in ink comparative examples 4-6, the quantum dots in ink example 2 have a narrower half-width and higher color purity.

[0187] Device Example 1

[0188] Provide an ITO anode glass substrate, wipe the ITO surface with a cotton swab dipped in a small amount of soapy water to remove visible impurities, then ultrasonically clean it with deionized water, acetone, ethanol, and isopropanol for 15 minutes, and then dry it with nitrogen gas for later use.

[0189] PEDOT:PSS material was spin-coated onto the anode and annealed at 150°C for 15 min to obtain a hole injection layer with a thickness of 25 nm.

[0190] TFB material was spin-coated onto the hole injection layer and annealed at 150°C for 15 min to obtain a hole transport layer with a thickness of 25 nm.

[0191] A thin film with a thickness of 30 nm was prepared on the hole transport layer using the preparation method of ink Example 1;

[0192] An ethanol solution of ZnO was spin-coated onto the light-emitting layer and annealed at 180°C for 15 min to obtain an electron transport layer with a thickness of 30 nm.

[0193] In a vacuum coating machine, thermal evaporation is performed at a vacuum level of 4×10⁻⁶. -6 mbar, Mg is vapor-deposited to form a Mg layer with a thickness of 8nm; then Ag is vapor-deposited on the Mg layer to form an Ag layer with a thickness of 100nm, thus obtaining the cathode;

[0194] Encapsulation yields a light-emitting device.

[0195] Device Examples 2-18

[0196] Device Examples 2 to 18 are basically the same as Device Example 1, except that the light-emitting layer of Device Examples 2 to 18 is prepared using the same preparation method as that of Ink Examples 2 to 18.

[0197] Device Comparison Examples 1-6

[0198] The devices in Comparative Examples 1 to 6 are basically the same as those in Device Example 1, except that the light-emitting layers in Comparative Examples 1 to 6 are prepared using the same methods as those in Comparative Examples 1 to 6.

[0199] The external quantum efficiency (EQE), lifetime (T95), and lifetime (T95@1000 nit) of the light-emitting devices in Device Examples 1-18 and Device Comparative Examples 1-6 were tested. The test results are shown in Table 2.

[0200] External quantum efficiency (EQE) is the ratio of electron-hole pairs injected into a quantum dot to emitted photons, expressed as a percentage (%). It is an important parameter for evaluating the quality of electroluminescent devices and can be measured using an EQE optical testing instrument. The specific calculation formula is as follows:

[0201]

[0202] Where ηe is the optical output coupling efficiency, ηr is the ratio of the number of recombinated carriers to the number of injected carriers, χ is the ratio of the number of excitons that generate photons to the total number of excitons, KR is the radiative process rate, and KNR is the non-radiative process rate.

[0203] The lifetime T95 and lifetime T95@1000nit test methods are as follows: In CDA gas, under a constant current of 2mA, the time it takes for the device brightness to decay to a certain percentage of its maximum brightness is measured. The time for the brightness to decay to 95% of the maximum brightness is defined as T95, and this lifetime is the measured lifetime. To shorten the lifetime testing cycle, device lifetime testing is usually performed at high brightness by accelerating device aging, and the lifetime at low brightness is obtained by fitting the decay fitting formula. For example, the lifetime at 1000 nits is denoted as T95@1000nits, and the calculation formula is as follows:

[0204]

[0205] Among them, T95 L The lifespan at low brightness is typically taken as the lifespan at 1000 nits, T95. H The lifetime at high brightness, i.e., the measured lifetime, L H L is the maximum brightness that the device accelerates to. LTypically 1000 nits, A is the acceleration factor, taken as 1.7. EQE and lifetime testing conditions: conducted at room temperature with 50% humidity.

[0206] Table 2:

[0207]

[0208]

[0209] As shown in Table 2:

[0210] Compared to the light-emitting devices in Device Comparative Examples 1-6, the light-emitting devices in Device Examples 1-18 have higher external quantum efficiency and longer lifetime. It can be seen that the light-emitting layer of the light-emitting device prepared by the quantum dots described in this application can effectively improve the efficiency and lifetime of the light-emitting device. The reason may be that the composition of the core of the quantum dots described in this application is more uniform, which can effectively improve the luminescence of the quantum dots.

[0211] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing quantum dots, characterized in that, Includes the following steps: A nanocrystalline dispersion is provided, the nanocrystalline dispersion comprising nanocrystalline particles and a first solvent; A metal catalyst was added to the nanocrystalline dispersion for aging to obtain a reaction solution; Purification agent was added to the reaction solution to obtain alloy quantum dot cores. The alloy quantum dot cores were then dispersed in a second solvent to obtain a core solution. A shell cation source and a shell anion source are injected into the core solution to form a shell on the surface of the alloy quantum dot core, thereby obtaining the quantum dot.

2. The preparation method according to claim 1, characterized in that, It also includes at least one of the following features (1) to (2): (1) The molecular formula of the metal catalyst is: (R-COO) n M; Where n is an integer from 1 to 2; M is selected from Cu or Ag; R is selected from substituted or unsubstituted C8 to C9. 30 Chain alkyl groups, substituted or unsubstituted C8-C 30 alkenyl, substituted or unsubstituted C8-C 30 alkynyl, substituted or unsubstituted C6-C 30 aryl groups, or combinations thereof; The substituents mentioned above are each independently selected from C1 to C1, each time they appear. 20 Alkyl, C1-C 20 Alkoxy, C2-C 20 alkenyl, C2-C 20 One or more of the following: alkynyl group, F, Cl, Br, I; (2) The purifying agent includes an organophosphate, optionally, the organophosphate includes C3-C4. 30 dialkylphosphine, C3-C 30 One or more of the following: trialkylphosphine, diarylphosphine with 6 to 30 ring atoms, and triarylphosphine with 6 to 30 ring atoms.

3. The preparation method according to claim 2, characterized in that, It also includes at least one of the following features (1) to (8): (1) R is selected from substituted or unsubstituted C. 10 ~C 20 Chain alkyl, substituted or unsubstituted C 10 ~C 20 alkenyl, substituted or unsubstituted C 10 ~C 20 alkynyl, substituted or unsubstituted C6-C 20 aryl groups, or combinations thereof; (2) The R is selected from substituted or unsubstituted C. 10 ~C 18 Chain alkyl, substituted or unsubstituted C 10 ~C 18 alkenyl, substituted or unsubstituted C 10 ~C 18 alkynyl, substituted or unsubstituted C6-C 18 aryl groups, or combinations thereof; (3) The R is selected from substituted or unsubstituted C. 10 ~C 15 Chain alkyl, substituted or unsubstituted C 10 ~C 15 alkenyl, substituted or unsubstituted C 10 ~C 15 alkynyl, substituted or unsubstituted C6-C 15 aryl groups, or combinations thereof; (4) The substituents mentioned above are each independently selected from C1 to C1 each time they appear. 15 Alkyl, C1-C 15 Alkoxy, C2-C 15 alkenyl, C2-C 15 One or more of the following: alkynyl, -F, -Cl, -Br, -I; (5) The substituents mentioned above are each independently selected from C1 to C1 each time they appear. 10 Alkyl, C1-C 10 Alkoxy, C2-C 10 alkenyl, C2-C 10 One or more of the following: alkynyl, -F, -Cl, -Br, -I; (6) Each time the substituents appear, they are independently selected from one or more of C1-C5 alkyl, C1-C5 alkoxy, C2-C5 alkenyl, C2-C5 alkynyl, -F, -Cl, -Br, and -I; (7) The organophosphorus compounds include C3 to C4. 25 dialkylphosphine, C3-C 25 One or more of the following: trialkylphosphine, diarylphosphine with 6 to 20 ring atoms, and triarylphosphine with 6 to 20 ring atoms; (8) The organophosphorus compounds include C3 to C4. 20 dialkylphosphine, C3-C 25 One or more of the following: trialkylphosphine, diarylphosphine with 6 to 15 ring atoms, and triarylphosphine with 6 to 20 ring atoms.

4. The preparation method according to claim 2, characterized in that, The ripening temperature is 200–350°C; And / or, the ripening time is 1 to 120 minutes; And / or, the purification temperature is 280–350°C; And / or, the purification time is 5–60 min; And / or, the volume ratio of the purifying agent to the reaction solution is (0.01–0.2):1; And / or, the molar ratio of the metal catalyst to the metal cation in the nanocrystals is 1:(5-200); And / or, the molar ratio of the shell cation source to the shell anion source is (1-10):1; And / or, in the nanocrystal dispersion, the concentration of the nanocrystals is 5–100 mg / mL; And / or, the nuclear solution includes alloy quantum dot nuclei, the concentration of which is 5–100 mg / mL; And / or, the nanocrystals include one or more of alloy nanocrystals and core-shell nanocrystals, wherein the core-shell nanocrystals include a nanocrystal core and a shell layer enclosing the nanocrystal core, and the shell layer is one or more layers; And / or, the quantum dot is a core-shell quantum dot, which includes one or more shell layers.

5. The preparation method according to claim 4, characterized in that, The average particle size of the alloy nanocrystals is 2–10 nm. And / or, the average particle size of the nanocrystal nuclei is 2–10 nm; And / or, the average thickness of the shell layer of the core-shell nanocrystal is 0.5–3 nm; And / or, the average particle size of the quantum dots is 2–20 nm; And / or, the organophosphorus includes one or more of dioctylphosphine, tri-n-octylphosphine, tri-n-butylphosphine, diphenylphosphine, and triphenylphosphine; And / or, the shell cation source includes one or more of zinc compounds, cadmium compounds, silver compounds, indium compounds, mercury compounds, tin compounds, and lead compounds; And / or, the shell anion source includes at least one of sulfur powder, selenium powder and tellurium powder; And / or, the metal catalyst comprises one or more of copper compounds and silver compounds, wherein the copper compounds comprise one or more of copper oleate, copper palmitate, copper stearate, copper acetylacetone, copper laurate, and copper isopalmitoate, and the silver compounds comprise one or more of silver oleate, silver palmitate, silver stearate, silver acetylacetone, silver laurate, and silver isopalmitoate. And / or, the alloy nanocrystals are made of one or more of a first group II-VI compound and a first group IV-VI compound, wherein the first group II-VI compound includes one or more of CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, and the first group IV-VI compound includes one or more of SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; And / or, the material of the nanocrystal core of the core-shell nanocrystal and the material of the shell layer of the core-shell nanocrystal each independently include one or more of a second group II-VI compound and a second group IV-VI compound, wherein the second group II-VI compound includes 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, HgZ The second group IV-VI compound includes one or more of the following: nS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe; And / or, the core material of the core-shell quantum dots includes one or more of Group II-VI compounds and Group IV-VI compounds, wherein the Group II-VI compounds include one or more of CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, and the Group IV-VI compounds include one or more of SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; And / or, the shell material of the core-shell quantum dots comprises one or more of group II-VI and group IV-VI compounds, wherein the group II-VI compounds include 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, and HgZnSe. The fourth group IV-VI compound includes one or more of SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, and SnPbSTe; And / or, the first solvent and the second solvent each independently include one or more of the following: n-octane, isooctane, n-hexane, cyclohexane, ethyl acetate, benzene, toluene, chloroform, carbon tetrachloride, dichloromethane, dimethyl ether, 1-octadecene, and tetraethylene glycol dimethyl ether.

6. The preparation method according to claim 1, characterized in that, The purification process also includes microwave treatment, wherein: The wavelength of the microwaves used in the microwave processing is 0.1 to 1000 mm. And / or, the frequency of the microwaves used in the microwave processing is 0.3 to 3000 GHz; And / or, the time period for the combined purification and microwave treatment is 5 to 60 minutes.

7. A quantum dot, characterized in that, The quantum dots are prepared by the preparation method according to any one of claims 1 to 6.

8. A thin film, characterized in that, The thin film comprises quantum dots prepared by the preparation method according to any one of claims 1 to 6, or the thin film comprises quantum dots according to claim 7.

9. A light-emitting device, characterized in that, It comprises an anode, a light-emitting layer, and a cathode stacked sequentially, wherein the light-emitting layer comprises quantum dots prepared by the preparation method according to any one of claims 1 to 6, or the light-emitting layer comprises quantum dots as described in claim 7, or the light-emitting layer is a thin film as described in claim 8.

10. The light-emitting device as described in claim 9, characterized in that, The anode and the cathode each independently include a doped metal oxide particle electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal element electrode, or an alloy electrode. The material of the doped metal oxide particle electrode includes one or more of indium-doped tin oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, magnesium-doped zinc oxide, and aluminum-doped magnesium oxide. The composite electrode includes one or more of AZO / Ag / AZO, AZO / Al / AZO, ITO / Ag / ITO, ITO / Al / ITO, ZnO / Ag / ZnO, ZnO / Al / ZnO, TiO2 / Ag / TiO2, TiO2 / Al / TiO2, ZnS / Ag / ZnS, or ZnS / Al / ZnS. The material of the metal element electrode includes one or more of Ag, Al, Cu, Mo, Au, Pt, Ca, Mg, and Ba. And / or, the light-emitting device further includes an electron transport layer located between the light-emitting layer and the cathode, wherein the material of the electron transport layer is selected from one or more of inorganic electron transport materials and organic electron transport materials, the inorganic electron transport material including one or more of first doped metal oxide particles, first undoped metal oxide particles, group IIB-VIA semiconductor materials, group IIIA-VA semiconductor materials, and group IB-IIIA-VIA semiconductor materials, the material of the first undoped metal oxide particles including one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5, and the material of the first doped metal oxide particles including one or more of ZnO, TiO2, SnO2, ZrO2, and Ta2O5. The metal oxides in the oxide particles include one or more of ZnO, TiO2, SnO2, ZrO2, Ta2O5, and Al2O3; the doping elements in the first doped metal oxide particles include one or more of Al, Mg, Li, Mn, Y, La, Cu, Ni, Zr, Ce, In, and Ga; the IIB-VIA group semiconductor materials include one or more of ZnS, ZnSe, and CdS; the IIIA-VA group semiconductor materials include one or more of InP and GaP; and the IB-IIIA-VIA group semiconductor materials include one or more of CuInS and CuGaS.The organic electron transport materials include diphenyl[4-(triphenylsilyl)phenyl]phosphine oxide, 1,3,5-tris((3-pyridyl)-3-phenyl)benzene, 2-(4-biphenyl)-5-phenyloxadiazole, bis(10-hydroxybenzo[h]quinoline)beryllium, 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole, and 2,7-bis(diphenylphosphine)- 9,9'-spirobis[fluorene], 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 4,6-bis(3,5-di(3-pyridinylphenyl)-2-methylpyrimidine 4,7-diphenyl-1,10-phenanthroline, 2-(4'-tert-butylphenyl)-5-(4'-biphenyl)-1,3,4-oxadiazole, 2,9-dimethyl-4,7-diphenyl-1,10-o-diazaphenanthroline, 4, 7-Diphenyl-1,10-o-phenanthroline, bis(2-methyl-8-hydroxyquinoline-N1,O8)-1,1'-biphenyl-4-hydroxy)aluminum, 8-hydroxyquinoline aluminum, 2,7-bis(diphenyloxyphosphino)-9,9'-spirobis[fluorene], poly[9,9-dioctylfluorene-9,9-bis(N,N-dimethylaminopropyl)fluorene], 9,9-bis[3'-(N,N-dimethylamino)propyl-2,7- [fluorene]-alternating-2,7-(9,9-dioctylfluorene), 1,3-bis[5-(4-tert-butylphenyl)-2-[1,3,4]oxadiazolyl]benzene, 3',3'",3'""-(1,3,5-triazine-2,4,6-triyl)-tris(([1,1'-biphenyl]-3-carboxynitrile)), 2,4,6-tris[3-(diphenylphosphoxy)phenyl]-1,3,5-triazole; And / or, the light-emitting device further includes a hole transport layer located between the anode and the light-emitting layer, wherein the material of the hole transport layer includes one or more of inorganic hole transport materials and organic hole transport materials, wherein the inorganic hole transport material includes one or more of second doped metal oxide particles, second undoped metal oxide particles, metal sulfides, metal selenides, and metal nitrides, wherein the metal oxides in the second doped metal oxide particles and the metal oxides in the second undoped metal oxide particles each independently include one or more of MoO3, WO3, NiO, CrO3, CuO, Cu2O, and V2O5, wherein the doping element in the second doped metal oxide particles includes one or more of Mo, W, Ni, Cr, Cu, and V, wherein the metal sulfide includes one or more of CuS, MoS3, and WS3, wherein the metal selenide includes one or more of MoSe3 and WSe3, and wherein the metal nitride includes p-type gallium nitride;The organic hole transport material includes 4,4'-N,N'-dicarbazolyl-biphenyl, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], N,N'-diphenyl-N,N'-bis(1-naphthyl)-1,1'-biphenyl-4,4”-diamine, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)biphenylamine), N,N'-bis(3-methylphenyl)-biphenyl-4,4'-diamine, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)biphenylamine), N,N'-bis(3-methylphenyl)biphenyl- ... 4,4',4'-tris(N-carbazolyl)-triphenylamine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, poly[(9,9'-dioctylfluorene-2,7-diyl)co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))], poly(N-vinylcarbazole) and its derivatives, N,N'- Bis(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4-4'-diamine, spiroNPB, poly(phenylenevinylene), poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, 4,4'-cyclohexyldi[N,N-di(4-] [Methylphenyl)aniline], 1,3-bis(carbazole-9-yl)benzene, polyaniline, polypyrrole, poly(p-)phenylenevinylene, aromatic tertiary amine, polynuclear aromatic tertiary amine, 4,4'-bis(p-carbazole)-1,1'-biphenyl compounds, N,N,N',N'-tetraarylbenzidine, PEDOT:PSS and its derivatives, polymethacrylate and its derivatives, poly(9,9-octylfluorene) and its derivatives, poly(spirofluorene) and its derivatives, doped graphene, undoped graphene, and one or more of C60; And / or, the light-emitting device further includes a hole injection layer located between the anode and the light-emitting layer, the hole injection layer being made of one or more of the following materials: 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, PEDOT, PEDOT:PSS, PEDOT:PSS derivatives doped with s-MoO3, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, tetracyanoquinone dimethyl ether, copper phthalocyanine, nickel oxide, molybdenum oxide, tungsten oxide, vanadium oxide, molybdenum sulfide, tungsten sulfide, and copper oxide.

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