Ink, light-emitting device and application

Abstract

The embodiment of the application belongs to the technical field of display, and relates to an ink, a light-emitting device and application. The ink provided in the application comprises an N-type self-doped material having a carrier transport function. A charge generation unit prepared from the N-type self-doped material can efficiently generate charges and separate the charges, so that the charges are prevented from accumulating at an interface, thereby improving the carrier transport efficiency, and further improving the light-emitting performance and stability of the light-emitting device.

Description

Technical Field

[0001] This application relates to the field of display technology, and more specifically, to an ink, a light-emitting device, and its application. Background Technology

[0002] In future display and lighting technologies, organic light-emitting diodes (OLEDs) and quantum dot light-emitting diodes (QLEDs) will become mainstream due to their absolute advantages. However, further optimization of LED performance remains extremely challenging for competing light sources and displays with ideal standards.

[0003] Stacked devices connect at least two light-emitting units in series via a charge generation layer (CGL). Under the same product specifications, stacked devices offer a combination of superior brightness, efficiency, and lifetime compared to single-layer devices, making them a future product necessity. However, the mainstream CGLs in current vapor deposition methods consist of p-type doped p-CGLs and n-type doped n-CGLs. In vapor deposition, n-CGLs are typically a combination of electron transport materials and N-type doped materials. N-type doped materials are usually highly reactive N-type metal dopants, which cannot be solution-processed. In solution methods, strong N-type transport materials are typically ZnO and doped ZnO derivatives. However, there is a significant potential barrier between ZnO and organic light-emitting materials, preventing effective charge injection into the light-emitting layer. Furthermore, the significant difference in thermal expansion coefficients between inorganic materials and organic compounds means that thermal stress cannot be effectively released during annealing, leading to film cracking and resulting in poor luminescence performance and stability of the light-emitting device. Summary of the Invention

[0004] The purpose of this application is to provide an ink, a thin film, a light-emitting device, and its application, thereby improving the light-emitting performance and stability of the device.

[0005] To address the aforementioned technical problems, this application provides an ink comprising an N-type self-doped material with carrier transport functionality.

[0006] To address the aforementioned technical problems, this application also provides a light-emitting device, comprising:

[0007] Anode and cathode arranged opposite each other;

[0008] At least two light-emitting units are stacked sequentially between the anode and the cathode;

[0009] At least one charge generating unit is disposed between two adjacent light-emitting units;

[0010] The charge generation unit includes an N-type charge generation layer and a P-type charge generation layer stacked together. The N-type charge generation layer is disposed near the anode, and the P-type charge generation layer is disposed near the cathode. The N-type charge generation layer is made of ink as described above, or includes an N-type self-doped material with carrier transport function.

[0011] To address the aforementioned technical problems, this application also provides a display device, which includes the light-emitting device described above.

[0012] Compared with the prior art, this application has the following main advantages:

[0013] This application provides an ink comprising an N-type self-doped material with charge carrier transport function, which enhances conductivity and solvent resistance, thereby enabling the light-emitting device containing the N-type self-doped material to have a denser film layer and better light-emitting performance and stability. Attached Figure Description

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

[0015] Figure 1 This is a schematic diagram of the structure of the light-emitting device provided in this application. Figure 1 ;

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

[0017] Reference numerals: 100, anode; 200, cathode; 301, first light-emitting unit; 302, second light-emitting unit; 400, charge-generating unit; 401, N-type charge-generating layer; 402, P-type charge-generating layer; 3011, first light-emitting layer; 3012, first hole functional layer; 3013, first electron functional layer; 3021, second light-emitting layer; 3022, second hole functional layer; 3023, second electron functional layer. Detailed Implementation

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] In this application, "substitution" means that the hydrogen atom in the substituent is replaced by the substituent.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] "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" means 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, 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.

[0026] "Heteroaryl or heteroaromatic group" refers to an aryl group in which at least one carbon atom is replaced by a non-carbon atom, which can be an N atom, O atom, S atom, etc. For example, "substituted or unsubstituted heteroaryl group having 5 to 40 ring atoms" refers to a heteroaryl group having 5 to 40 ring atoms, preferably a substituted or unsubstituted heteroaryl group having 6 to 30 ring atoms, more preferably a substituted or unsubstituted heteroaryl group having 6 to 18 ring atoms, and particularly preferably a substituted or unsubstituted heteroaryl group having 6 to 14 ring atoms. The heteroaryl group may optionally be further substituted, and suitable examples include, but are not limited to: thiophene, furanyl, pyrrole, imidazole, triazolyl, imidazole, diazolyl, triazolyl, pyridyl, bipyridyl, pyrimidinyl, triazinyl, triazolyl, acridine, pyridazinyl, pyridinyl, etc. Azinyl, quinolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, pyridinylpyrimidinyl, pyridinylpyrazinyl, pyrazinylpyrazinyl, isoquinolinyl, indolyl, carbazoleyl, benzothiopheneyl, benzofuranyl, indolyl, carbazoleyl, pyrroloimidazolyl, pyrrolopyrrololyl, thienopyrrololyl, thienopyrrololyl, furanolol, furanol, thienofuranyl, benzoisoxazolyl, benzoisothiazolyl, benzoimidazolyl, quinolinyl, isoquinolinyl, o-diazonaphthyl, quinoxalinyl, phenanthridine, primidyl, quinazolinyl, quinazolinone, dibenzothiopheneyl, dibenzofuranyl, carbazoleyl and their derivatives.

[0027] In this application, "alkyl" can refer to straight-chain or branched 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 time it appears, it 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, 2-ethylbutyl, 3,3-dimethylbutyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-methylpentyl, 3-methylpentyl, 2-ethylpentyl, 4-methyl-2-pentyl, n-hexyl, 1-methylhexyl, 2-ethylhexyl, 2-butylhexyl, n-heptyl, 1-methylheptyl, 2,2-dimethylheptyl, 2-ethylheptyl, 2-butylheptyl, n-octyl, tert-octyl, 2-ethyloctyl, 2-butyloctyl, 2-hexyloctyl, 3,7-dimethyloctyl, n-nonyl, n-decyl, adamantyl, 2-ethyldecyl, 2-butyldecyl, 2-hexyldecyl, 2-octyldecyl The compounds include: n-undecyl, n-dodecyl, 2-ethyldodecyl, 2-butyldodecyl, 2-hexyldodecyl, 2-octyldodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, 2-ethylhexadecyl, 2-butylhexadecyl, 2-hexylhexadecyl, 2-octylhexadecyl, n-heptadecyl, n-octadecyl, n-heptadecyl, n-eicosyl, 2-ethyleicosyl, 2-butyleicosyl, 2-hexyleicosyl, 2-octyleicosyl, n-monodecyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, n-eicosyl, and adamantane.

[0028] In this application, "alkoxy" refers to a group with the structure "-O-alkyl", that is, an alkyl group as defined above that is attached to other groups via an oxygen atom. Suitable examples of phrases containing this term include, but are not limited to: methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt), and tert-butoxy (-OC(CH3)3 or -OtBu).

[0029] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0030] This application provides an ink comprising an N-type self-doped material with carrier transport function. The self-doped N-type material participates in carrier transport through free lone pairs of electrons in its material structure, thereby imparting high carrier transport and improving overall conductivity.

[0031] Self-doping refers to the process of modifying and optimizing the chemical structure of N-type materials by introducing functionalizable groups into segments of the main chain or side chain, thereby enabling the N-type materials to combine with or separate from metal ions and thus improve their electrical conductivity.

[0032] In some embodiments, the N-type self-doped material has the following structural formula:

[0033]

[0034] Wherein, n is selected from an integer greater than 0; Ar is selected from at least one of aryl groups with 6 to 60 substituted or unsubstituted carbon atoms, and heteroaryl groups with 5 to 60 substituted or unsubstituted carbon atoms;

[0035] R is selected from one or more combinations of hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, ether alkyl, carbonyl alkyl, a chain hydrocarbon group having 1 to 30 substituted or unsubstituted carbon atoms, a chain alkyloxy group having 1 to 30 substituted or unsubstituted carbon atoms, a cyclic hydrocarbon group having 3 to 60 substituted or unsubstituted carbon atoms, a heterocyclic hydrocarbon group having 3 to 60 substituted or unsubstituted carbon atoms, an aryl group having 6 to 60 substituted or unsubstituted ring atoms, a heteroaryl group having 5 to 60 substituted or unsubstituted ring atoms, an aryloxy group having 5 to 60 substituted or unsubstituted ring atoms, and a heteroaryloxy group having 5 to 60 substituted or unsubstituted ring atoms.

[0036] Among them, the heteroatoms in the heteroaryl or heteroaryloxy group are N, S, O, P, Si, or B, and the number of heteroatoms is 1-20;

[0037] When substituted, each substituent is independently selected from one or more combinations of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, and hydroxyl groups.

[0038] The N-type self-doped material of this application contains imide groups, which contain oxygen and nitrogen atoms with high electronegativity, thus exhibiting a strong electron-withdrawing ability, effectively increasing the carrier concentration and improving the electronic conductivity. Secondly, the N-type self-doped material of this application has a high molecular weight, which increases its resistance to solvents, thereby preventing it from being eroded by the upper solvent layer.

[0039] In some embodiments, the N-type self-doped material has the following structural formula:

[0040]

[0041] R1 and R2 are each independently selected from one or more of the following groups: hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, ether alkyl, carbonyl alkyl, substituted or unsubstituted alkyl with 1 to 30 carbon atoms, substituted or unsubstituted alkoxy with 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 30 carbon atoms, substituted or unsubstituted heterocycloalkyl with 3 to 30 carbon atoms, substituted or unsubstituted aryl with 6 to 60 ring atoms, substituted or unsubstituted heteroaryl with 5 to 60 ring atoms, substituted or unsubstituted aryloxy with 5 to 60 ring atoms, and substituted or unsubstituted heteroaryloxy with 5 to 60 ring atoms.

[0042] When substituted, each substituent is independently selected from one or more combinations of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, and hydroxyl groups.

[0043] The symmetrical imide groups make the entire molecular structure more balanced and stable, thereby improving the efficiency and stability of electron transport and increasing conductivity.

[0044] In some embodiments, the N-type self-doped material is selected from at least one of the following structural formulas:

[0045]

[0046] Each time X appears, it is independently selected from CR7 or N;

[0047] R3, R4, R5, R6 and R7, each time appearing, are independently selected from one or more of the following: hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, ether alkyl, carbonyl alkyl, substituted or unsubstituted alkyl having 1 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted heterocycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 60 ring atoms, substituted or unsubstituted heteroaryl having 5 to 60 ring atoms, substituted or unsubstituted aryloxy having 5 to 60 ring atoms, and substituted or unsubstituted heteroaryloxy having 5 to 60 ring atoms.

[0048] Each occurrence of Ar2 is independently selected from at least one of aryl groups having 6 to 60 substituted or unsubstituted carbon atoms, or heteroaryl groups having 5 to 60 substituted or unsubstituted carbon atoms.

[0049] In some embodiments, when R3, R4, R5, R6, R7 and Ar2 are substituted with substituents, each substituent is independently selected from one or more combinations of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, and hydroxyl groups.

[0050] In some embodiments, the N-type self-doped material is selected from at least one of the following structural formulas:

[0051]

[0052]

[0053]

[0054] The synthesis methods for M1 to M17 are referenced in the following documents: doi:10.1002 / cplu.202400286, doi:10.1039 / d2cs01027e, doi:10.1039 / d1tc06175e, doi:10.1021 / acsami.1c13394, doi:10.1002 / anie.200461324, doi:10.1021 / cm0704579, doi:10.1021 / ja910667y, doi:10.1016 / j.tet.2014.04.002, and doi:10.1039 / D2PY01430K.

[0055] The N-type self-doped material of this application can increase carrier concentration, enhance charge transport, improve the charge separation capability of the CGL itself, promote charge balance inside the CGL or at the interface, thereby reducing device voltage and extending device lifetime.

[0056] In some embodiments, the ink further includes a solvent, wherein the solvent is selected from one or more of aromatic or heteroaromatic solvents, aromatic ester solvents, aromatic ketone solvents, aromatic ether solvents, aliphatic ketone solvents, and aliphatic ether solvents.

[0057] In some embodiments, the aromatic or heteroaromatic solvent is selected from p-diisopropylbenzene, pentamene, tetrahydronaphthalene, cyclohexylbenzene, chloronaphthalene, 1,4-dimethylnaphthalene, 3-isopropylbiphenyl, p-methylisopropylbenzene, dipentene, tripentene, pentamethylene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, butylbenzene, dodecylbenzene, dihexylbenzene, dibutylbenzene, p-diisopropylbenzene, cyclohexylbenzene, benzylbutylbenzene, dimethylnaphthalene, 3-isopropylbiphenyl, One or more of the following: p-methylisopropylbenzene, 1-methylnaphthalene, 1,2,4-trichlorobenzene, 4,4-difluorodiphenylmethane, 1,2-dimethoxy-4-(1-propenyl)benzene, diphenylmethane, 2-phenylpyridine, 3-phenylpyridine, N-methyldiphenylamine, 4-isopropylbiphenyl, α,α-dichlorodiphenylmethane, 4-(3-phenylpropyl)pyridine, benzyl benzoate, 1,1-bis(3,4-dimethylphenyl)ethane, 2-isopropylnaphthalene, quinoline, isoquinoline, methyl 2-furanate, and ethyl 2-furanate; and / or,

[0058] The ester solvent is selected from one or more of the following: alkyl octanoate, alkyl sebacate, alkyl stearate, alkyl benzoate, alkyl phenylacetate, alkyl cinnamate, alkyl oxalate, alkyl maleate, alkyl lactone, and alkyl oleate; and / or,

[0059] The aromatic ketone solvent is selected from one or more of 1-tetrahydronaphthone, 2-tetrahydronaphthone, 2-(phenylepoxy)tetrahydronaphthone, 6-(methoxy)tetrahydronaphthone, acetophenone, phenylacetone, benzophenone, and their derivatives, wherein the derivatives may be selected from one or more of 4-methylacetophenone, 3-methylacetophenone, 2-methylacetophenone, 4-methylphenylacetone, 3-methylphenylacetone, and 2-methylphenylacetone; and / or,

[0060] The aromatic ether solvent is selected from one or more of 3-phenoxytoluene, butoxybenzene, p-anisaldehyde dimethyl acetal, tetrahydro-2-phenoxy-2H-pyran, 1,2-dimethoxy-4-(1-propenyl)benzene, 1,4-benzodioxane, 1,3-dipropylbenzene, 2,5-dimethoxytoluene, 4-ethylbenzene, 1,3-dipropoxybenzene, 1,2,4-trimethoxybenzene, 4-(1-propenyl)-1,2-dimethoxybenzene, 1,3-dimethoxybenzene, glycidyl phenyl ether, dibenzyl ether, 4-tert-butylanisole, trans-p-propenylanisole, 1,2-dimethoxybenzene, 1-methoxynaphthalene, diphenyl ether, 2-phenoxymethyl ether, 2-phenoxytetrahydrofuran, and ethyl-2-naphthyl ether; and / or,

[0061] Aliphatic ketone solvents are selected from one or more of 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 2,5-hexanedione, 2,6,8-trimethyl-4-nonanone, flavone, phorone, isophorone, and di-n-pentyl ketone; and / or,

[0062] Aliphatic ether solvents are selected from one or more of the following: pentylene ether, hexyl ether, dioctyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol ethyl methyl ether, triethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether.

[0063] It is understood that the above solvents can be used alone or as a mixture of two or more solvents.

[0064] In some embodiments, suitable solvents for this application are solvents with Hansen solubility parameters within the following ranges:

[0065] δ d (Dispersion force) in the range of 17.0-23.2 MPa 1 / 2 Within the range, especially in the 18.5-21.0 MPa range. 1 / 2 Within the range;

[0066] δ p (Polar force) in the range of 0.2-12.5 MPa 1 / 2 Within the range, especially in the 2.0-6.0 MPa range. 1 / 2 Within the range;

[0067] δ h (Hydrogen bond strength) in the range of 0.9-14.2 MPa 1 / 2 Within the range, especially in the 2.0-6.0 MPa range. 1 / 2 Within the range.

[0068] In some embodiments, the solvent for the ink according to this application is selected with boiling point in mind. In at least some embodiments, the solvent has a boiling point ≥150°C; preferably ≥180°C; more preferably ≥200°C; and even more preferably ≥250°C. Boiling points within these ranges are beneficial for preventing nozzle clogging of the inkjet printhead.

[0069] It is understood that the solvent can evaporate from the solvent system to form a thin film comprising the aforementioned organic compounds.

[0070] In some embodiments, the surface tension of the ink at 25°C ranges from 19 dyne / cm to 60 dyne / cm, for example, from 22 dyne / cm to 55 dyne / cm, or from 25 dyne / cm to 40 dyne / cm, or from 30 dyne / cm to 40 dyne / cm.

[0071] In some embodiments, the viscosity of the ink at 25°C ranges from 1 cps to 100 cps, for example, from 1 cps to 10 cps, from 1 cps to 50 cps, from 1.5 cps to 20 cps, or from 2.0 cps to 15 cps.

[0072] The solvents mentioned above are all common solvents, which help improve the solubility of N-type self-doped materials and enhance ink stability.

[0073] In some embodiments, the mass concentration of the N-type self-doped material in the ink is 0.5% to 10%. Specifically, the mass concentration of the ink can be 0.5% to 1%, 0.5% to 2%, 0.5% to 5%, 0.5% to 8%, 1% to 3%, 1% to 5%, 1% to 7%, 1% to 10%, 2% to 6%, 2% to 9%, 2% to 10%, 4% to 5%, 4% to 8%, 4% to 10%, 5% to 10%, 6% to 10%, 7% to 10%, or 8% to 10%. The specific mass concentration can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. The specific mass concentration can be selected according to actual conditions and is not limited here.

[0074] In this embodiment, a suitable ink mass concentration can improve ink quality and help form a high-quality film layer.

[0075] This application provides a thin film prepared using the aforementioned ink. The organic compound is an N-type self-doped material with carrier transport capabilities.

[0076] In this embodiment, the method for preparing the above-mentioned thin film includes the following steps:

[0077] Step S21: Provide ink, the ink comprising an N-type self-doped material and a solvent;

[0078] Step S22: Deposit ink to obtain a thin film.

[0079] In at least one embodiment, the film-forming process is a solution method, which may include spin coating, printing, inkjet printing, blade coating, printing, dip-coating, immersion, spraying, roller coating, casting, slot coating, and strip coating, etc.

[0080] This application also provides a light-emitting device, such as... Figure 1 As shown, it includes:

[0081] The anode 100 and cathode 200 are set opposite to each other;

[0082] At least two light-emitting units 301 and 302 are stacked sequentially between the anode 100 and the cathode 200;

[0083] At least one charge generating unit 400 is disposed between two adjacent light-emitting units 301 and 302;

[0084] The charge generation unit 400 includes an N-type charge generation layer 401 and a P-type charge generation layer 402 stacked together. The N-type charge generation layer 401 is disposed near the anode 100, and the P-type charge generation layer 402 is disposed near the cathode 200. The N-type charge generation layer 401 is made of ink as described above and includes the aforementioned N-type self-doped material with carrier transport function.

[0085] Among them, 301 is the first light-emitting unit and 302 is the second light-emitting unit. The first light-emitting unit 301 is disposed on the side closer to the anode 100, and the second light-emitting unit 302 is disposed on the side closer to the cathode 200.

[0086] In this embodiment, the N-type charge generation layer 401 includes the thin film as described above. The thin film includes an N-type self-doped material. The N-type self-doped material has strongly electron-withdrawing imide groups. The lone electron pairs of the amine groups in the imide groups participate in the charge transport of the main chain of the N-type self-doped material, enhancing conductivity and thereby improving the charge generation and separation capability of the charge generation unit 400. This allows electrons from the N-type charge generation layer 401 to be efficiently injected into the first light-emitting unit 301, and holes from the P-type charge generation layer 402 to be efficiently injected into the second light-emitting unit 302, thereby improving the photoelectric performance of the light-emitting device.

[0087] In some embodiments, the material of the P-type charge generation layer includes a hole transport material and a P-type doped material, wherein the P-type doped material is selected from at least one of PEDOT:PSS, PEDOT:PSS-PFI, NDP-9, NDP-2, F4-TCNQ, F6-TCNNQ, HATCN, tetrafluorotetracyanoquinone dimethyl ether, 7,7,8,8-tetracyano-p-benzoquinone dimethyl ether, pentanebenzene, CuPc, WO3, MoO3, NiO, V2O5, CuO, WS2, and MoS2; and / or,

[0088] The hole transport material is selected from 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)benzidine), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)spiro, N,N'- At least one of the following: bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 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, and spiron NPB.

[0089] In some embodiments, each light-emitting unit 300 in the light-emitting device independently includes a light-emitting layer. For example, see [example image]. Figure 2 As shown, the first light-emitting unit 301 includes a first light-emitting layer 3011, and the second light-emitting unit 302 includes a second light-emitting layer 3021.

[0090] The material of the light-emitting layer is an organic light-emitting material or a quantum dot light-emitting material; the organic light-emitting material includes one or more of the following: TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, TADF material, TTA material, polymers containing BN covalent bonds, hybrid local charge transfer excited state materials, excitocomplex light-emitting materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives; the quantum dot light-emitting material includes one or more of the following: single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials, wherein the shell of the core-shell structure quantum dots comprises one or more layers;The materials of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are each independently selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, and HgSeT. One or more of the following compounds: e, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, wherein the group IV-VI compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, and SnSe. Te, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, and SnPb, wherein the III-V compound comprises one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, and Al One or more of PSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, wherein the group I-III-VI compounds include one or more of CuInS2, CuInSe2, and AgInS2;The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The perovskite quantum dot luminescent material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The general structural formula of the inorganic perovskite semiconductor is AMX3, where A is cesium, M includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X is a halogen, including one or more of chlorine, bromine, and iodine. The general structural formula of the organic-inorganic hybrid perovskite semiconductor is BM'X'3, where B includes CH3(CH2). n-2 NH3 or [NH3(CH2)] n [NH3], where n≥2, M' includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X' is a halogen, including one or more of chlorine, bromine, and iodine.

[0091] In some embodiments, each light-emitting unit in the light-emitting device further includes a hole functional layer and / or an electron functional layer independently. The hole functional layer is disposed on the side of the light-emitting layer near the anode, and the electron functional layer is disposed on the side of the light-emitting layer near the cathode. When each light-emitting unit includes a hole functional layer, a light-emitting layer, and an electron functional layer stacked sequentially, the N-type charge generation layer is disposed between the electron functional layer and the P-type charge generation layer of the light-emitting unit near the anode, and the P-type charge generation layer is disposed between the hole functional layer and the N-type charge generation layer of the light-emitting unit near the cathode.

[0092] For example, see Figure 2 As shown, the first light-emitting unit 301 includes a first hole functional layer 3012, a first light-emitting layer 3011, and a first electron functional layer 3013. The second light-emitting unit 302 includes a second hole functional layer 3022, a second light-emitting layer 3021, and a second electron functional layer 3023. An N-type charge generation layer is disposed on the side of the first electron functional layer 3013 near the cathode 200, and a P-type charge generation layer is disposed between the N-type charge generation layer and the second hole functional layer 3022.

[0093] The hole functional layer comprises a hole injection layer and / or a hole transport layer. The material of the hole injection layer is selected from at least one of poly(3,4-vinyldioxythiophene):poly(styrenesulfonic acid), copper phthalocyanine, titanium phthalocyanine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4'-tris[2-naphthylphenylamino]triphenylamine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, transition metal oxides, or transition metal chalcogenides. The transition metal oxide is selected from NiO. x MoO x WO x CrO x or CuO x At least one of the following, wherein the transition metal chalcogenide compound is selected from MoS x MoSe x WS x 、WSe x or CuS x At least one of the following; and / or, the material of the hole transport layer is selected from poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine), 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), poly[bis(4-phenyl)(4-butylphenyl)amine], poly(N,N'-bis(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene), 4,4',4”-tris(carbazole-9-yl)triphenylamine, 4,4'-bis( At least one of the following: 9-carbazole)biphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, poly(3,4-vinyldioxythiophene):poly(styrenesulfonic acid), doped or undoped graphene, C60, NiO, MoO3, WO3, V2O5, CrO3, CuO, or p-type gallium nitride; and / or,

[0094] The electronic functional layer includes an electron injection layer and / or an electron transport layer, wherein the materials of the electron transport layer and the electron injection layer independently include at least one of inorganic materials and organic compounds; the inorganic material is selected from one or more of the following: doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate; the doped elements include aluminum and magnesium. One or more of lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium, wherein the organic compound comprises one or more of 4,6-bis(3,5-bis(pyridin-3-yl)phenyl)-2-methylpyrimidine, 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline, 4,7-diphenyl-1,10-phenanthroline, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 8-hydroxyquinoline aluminum, 8-hydroxyquinoline lithium, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, and ion-conjugated polyelectrolytes, and / or,

[0095] The anode and the cathode each independently comprise a doped metal oxide electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal element electrode, or an alloy electrode. The doped metal oxide electrode is made of one or more of the following materials: indium-doped tin oxide, zinc-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, aluminum-doped magnesium oxide, and cadmium-doped zinc oxide. The composite electrode comprises AZO / Ag / AZO, AZO / APC / AZO, ITO / Ag / ITO, ITO / APC / ITO, IZO / Ag / IZO, and IZO. The metal element electrode is made of one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba, and the alloy electrode includes an Au:Mg alloy electrode or an Ag:Mg alloy electrode.

[0096] In some embodiments, taking two light-emitting units as an example, this application also provides a method for fabricating a light-emitting device, comprising:

[0097] The anode 100, the first light-emitting unit 301, the N-type charge generating layer 401, the P-type charge generating layer 402, the second light-emitting unit 302, and the cathode 200 are sequentially stacked.

[0098] For example, a method for fabricating a light-emitting device includes the following steps:

[0099] Step S31: Process the substrate with the anode.

[0100] The substrate can be a rigid substrate, such as glass, or a flexible substrate, such as PI. An anode is fabricated on the substrate, for example, an ITO substrate is formed, and then the ITO substrate is cleaned.

[0101] Step S32: Deposit a hole injection layer on the surface of the treated substrate.

[0102] Specifically, a hole injection layer material is deposited on the anode of the substrate to form a hole injection layer, wherein the thickness of the hole injection layer can be 20-100 nm.

[0103] Step S33: Prepare a hole transport layer on the hole injection layer.

[0104] Specifically, a hole transport layer material is deposited on the hole injection layer to form a hole transport layer, the thickness of which can be 30-50 nm.

[0105] Step S34: Prepare a light-emitting layer on the hole transport layer.

[0106] Specifically, the luminescent layer material is deposited on the hole transport layer to form the luminescent layer.

[0107] Step S35: Dissolve the organic compound of this application in a solvent to obtain ink, and deposit the ink on the light-emitting layer using a solution method to form an N-type charge generation layer.

[0108] Step S36: Prepare a P-type charge generation layer on the N-type charge generation layer.

[0109] The material of the P-type charge generation layer is deposited on the N-type charge generation layer to form the P-type charge generation layer.

[0110] Step S37: Deposit a light-emitting layer on the P-type charge generation layer, prepare an electron transport layer on the light-emitting layer, and prepare an electron injection layer on the electron transport layer.

[0111] Specifically, an electron transport layer material is deposited on the light-emitting layer to form an electron transport layer, and an electron injection layer material is deposited on the electron transport layer to form an electron injection layer.

[0112] Step S38: The cathode is prepared on the electron injection layer by vacuum evaporation of cathode material, thus obtaining the light-emitting device.

[0113] It should be noted that the material dissolution, mixing, preparation of each film layer, and post-treatment were all carried out in an N2 environment.

[0114] The following specific embodiments will be used to illustrate the contents of this application in more detail and to further elaborate on this application, but these embodiments are by no means intended to limit this application.

[0115] Example 1

[0116] This embodiment provides a light-emitting device, the fabrication method of which is as follows:

[0117] Step 1: Provide an ITO anode with a thickness of 50nm.

[0118] Step 2: PEDOT:PSS is deposited on the ITO anode and annealed at 150°C for 20 min to form a hole injection layer with an average thickness of 30 nm.

[0119] Step 3: Deposit TFB on the hole injection layer and anneal at 180°C for 20 min to form a hole transport layer with an average thickness of 20 nm.

[0120] Step 4: F8BT is solution deposited on the hole transport layer and annealed at 140°C for 20 min to obtain the light-emitting layer of the first light-emitting unit with a thickness of 55 nm.

[0121] Step 5: Dissolve the N-type self-doped material M1 in xylene to prepare ink. Deposit the ink on the light-emitting layer of the first light-emitting unit and anneal at 150°C for 20 min to obtain an N-type charge generation layer with a thickness of 30 nm.

[0122] Step 6: PVK:F4-TCNQ is deposited on the N-type charge generation layer by solution method and annealed at 150℃ for 20 min to obtain a P-type charge generation layer with a thickness of 20 nm.

[0123] In this process, the N-type charge generation layer and the P-type charge generation layer are in contact to form a charge generation unit of a stacked device with high charge generation and separation capabilities.

[0124] Step 7: Deposit F8BT using the P-type charge generation layer solution method, anneal at 140℃ for 20 min, to obtain the luminescent layer of the second luminescent unit with a thickness of 85 nm.

[0125] Step 8: Transfer the substrate to a vacuum level of 9*10 -7 In the vacuum chamber of the torr, NaF is deposited on the light-emitting layer of the second light-emitting unit to obtain an electron injection layer with a thickness of 3.5 nm.

[0126] Step nine: Deposit Al on the electron injection layer to obtain a cathode with a thickness of 100 nm. After removal and packaging, the light-emitting device is obtained.

[0127] Example 2

[0128] The difference between this embodiment and Embodiment 1 is that the N-type self-doped material is M2.

[0129] Example 3

[0130] The difference between this embodiment and Embodiment 1 is that the N-type self-doped material is M3.

[0131] Example 4

[0132] The difference between this embodiment and Embodiment 1 is that the N-type self-doped material is M4.

[0133] Example 5

[0134] The difference between this embodiment and Embodiment 1 is that the N-type self-doped material is M5.

[0135] Example 6

[0136] The difference between this embodiment and Embodiment 1 is that the N-type self-doped material is M7.

[0137] Example 7

[0138] The difference between this embodiment and Embodiment 1 is that the N-type self-doped material is M9.

[0139] Comparative Example 1

[0140] The difference between this comparative example and Example 1 is that the material of the N-type charge generation layer is ZnO.

[0141] Test Result Analysis:

[0142] Experimental tests and analyses were conducted on the light-emitting devices in Examples 1-7 and Comparative Example 1. The test results are shown in Table 1. The voltages in the table refer to the voltages at a current density of 10 mA / cm². 2 The device voltage at that time, efficiency@1000nit refers to the device efficiency at 1000nit, LT95@1000nit refers to the lifetime at 1000nit when the brightness decays from 100% to 95%, and J10 voltage is related to the charge generation and separation capability of CGL.

[0143] Table 1 Performance test results of light-emitting devices

[0144]

[0145]

[0146] The conductivity results of the N-type material thin films in Examples 1-7 and Comparative Example 1 are shown in Table 2.

[0147] Table 2

[0148] Electrical conductivity (S / m) Thin Film Example 1 <![CDATA[6.63×10 -3 ]]> Thin Film Example 2 <![CDATA[6.04×10 -3 ]]> Thin Film Example 3 <![CDATA[6.21×10 -3 ]]> Thin Film Example 4 <![CDATA[5.98×10 -3 ]]> Thin Film Example 5 <![CDATA[6.09×10 -3 ]]> Thin Film Example 6 <![CDATA[5.16×10 -3 ]]> Thin Film Example 7 <![CDATA[7.09×10 -3 ]]> Thin Film Comparative Example 1 <![CDATA[2.83×10 -3 ]]>

[0149] As shown in the table above, for Comparative Example 1, zinc oxide is an inorganic material with a significantly different coefficient of thermal expansion compared to other organic functional layer materials. During thermal annealing, the thermal stress cannot be effectively released, leading to varying degrees of cracking in the ZnO film, resulting in an inability to obtain a continuous and dense film. This results in very low conductivity of the film, which in turn leads to poor luminous efficiency and lifespan of the light-emitting device. For Examples 1-10, the N-type charge generation layer is prepared using N-type self-doped materials, resulting in better uniformity and density of the film. This significantly improves the conductivity of the film, enhances the charge generation and separation capabilities of the CGL, thereby improving the carrier transport efficiency of the device. It efficiently injects the corresponding carriers into the first and second light-emitting units, preventing long-term accumulation at the interface that could cause quenching, promoting charge balance, and improving the luminous efficiency and lifespan of the device.

[0150] This application also provides a display panel, which includes the organic compound or light-emitting device provided in the embodiments of this application.

[0151] This application also provides a display device, which includes the light-emitting device provided in the embodiments of this application, or includes the display panel as described above.

[0152] The high luminous efficiency of light-emitting devices results in high brightness for display panels and devices, while reducing their power consumption. Furthermore, the long lifespan of these devices also extends the lifespan of the display panels and devices.

[0153] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. An ink, characterized in that, The ink includes an N-type self-doped material with carrier transport capabilities.

2. The ink according to claim 1, characterized in that, The N-type self-doped material has the following structural formula: Wherein, n is selected from an integer greater than 0; Ar is selected from at least one of aryl groups with 6 to 60 substituted or unsubstituted carbon atoms, and heteroaryl groups with 5 to 60 substituted or unsubstituted carbon atoms; R is selected from one or more combinations of hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, ether alkyl, carbonyl alkyl, a chain hydrocarbon group having 1 to 30 substituted or unsubstituted carbon atoms, a chain alkyloxy group having 1 to 30 substituted or unsubstituted carbon atoms, a cyclic hydrocarbon group having 3 to 60 substituted or unsubstituted carbon atoms, a heterocyclic hydrocarbon group having 3 to 60 substituted or unsubstituted carbon atoms, an aryl group having 6 to 60 substituted or unsubstituted ring atoms, a heteroaryl group having 5 to 60 substituted or unsubstituted ring atoms, an aryloxy group having 5 to 60 substituted or unsubstituted ring atoms, and a heteroaryloxy group having 5 to 60 substituted or unsubstituted ring atoms. Among them, the heteroatoms in the heteroaryl or heteroaryloxy group are N, S, O, P, Si, or B, and the number of heteroatoms is 1-20; When substituted, each substituent is independently selected from one or more combinations of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, and hydroxyl groups.

3. The ink according to claim 2, characterized in that, The N-type self-doped material has the following structural formula: R1 and R2 are each independently selected from one or more of the following groups: hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, ether alkyl, carbonyl alkyl, substituted or unsubstituted alkyl with 1 to 30 carbon atoms, substituted or unsubstituted alkoxy with 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 30 carbon atoms, substituted or unsubstituted heterocycloalkyl with 3 to 30 carbon atoms, substituted or unsubstituted aryl with 6 to 60 ring atoms, substituted or unsubstituted heteroaryl with 5 to 60 ring atoms, substituted or unsubstituted aryloxy with 5 to 60 ring atoms, and substituted or unsubstituted heteroaryloxy with 5 to 60 ring atoms. When substituted, each substituent is independently selected from one or more combinations of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, and hydroxyl groups.

4. The ink according to claim 3, characterized in that, The N-type self-doped material is selected from at least one of the following structural formulas: Each time X appears, it is independently selected from CR7 or N; R3, R4, R5, R6 and R7, each time appearing, are independently selected from one or more of the following: hydrogen, deuterium, amino, halogen, hydroxyl, carboxyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, ether alkyl, carbonyl alkyl, substituted or unsubstituted alkyl having 1 to 30 carbon atoms, substituted or unsubstituted alkoxy having 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted heterocycloalkyl having 3 to 30 carbon atoms, substituted or unsubstituted aryl having 6 to 60 ring atoms, substituted or unsubstituted heteroaryl having 5 to 60 ring atoms, substituted or unsubstituted aryloxy having 5 to 60 ring atoms, and substituted or unsubstituted heteroaryloxy having 5 to 60 ring atoms. Each occurrence of Ar2 is independently selected from at least one of aryl groups having 6 to 60 carbon atoms (substituted or unsubstituted) and heteroaryl groups having 5 to 60 carbon atoms (substituted or unsubstituted); When substituted, each substituent is independently selected from one or more combinations of amino, halogen, hydroxyl, carboxyl, ester, acyl, nitro, sulfonic acid, aldehyde, mercapto, cyano, hydrocarbon, and hydroxyl groups.

5. The ink according to claim 4, characterized in that, The N-type self-doped material is selected from at least one of the following structural formulas:

6. The ink according to any one of claims 1 to 5, characterized in that, The ink further includes a solvent; wherein the solvent is selected from one or more of aromatic or heteroaromatic solvents, ester solvents, aromatic ketone solvents, aromatic ether solvents, aliphatic ketone solvents, and aliphatic ether solvents; and / or, Aromatic or heteroaromatic solvents are selected from p-diisopropylbenzene, pentobenzene, tetrahydronaphthalene, cyclohexylbenzene, chloronaphthalene, 1,4-dimethylnaphthalene, 3-isopropylbiphenyl, p-methylisopropylbenzene, dipentylbenzene, tripentylbenzene, pentyltoluene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, 1,2,4,5-tetramethylbenzene, butylbenzene, dodecylbenzene, dihexylbenzene, dibutylbenzene, p-diisopropylbenzene, cyclohexylbenzene, benzylbutylbenzene, dimethylnaphthalene, 3-isopropylbiphenyl, p-methylisopropylbenzene, etc. Propylbenzene, 1-methylnaphthalene, 1,2,4-trichlorobenzene, 4,4-difluorodiphenylmethane, 1,2-dimethoxy-4-(1-propenyl)benzene, diphenylmethane, 2-phenylpyridine, 3-phenylpyridine, N-methyldiphenylamine, 4-isopropylbiphenyl, α,α-dichlorodiphenylmethane, 4-(3-phenylpropyl)pyridine, benzyl benzoate, 1,1-bis(3,4-dimethylphenyl)ethane, 2-isopropylnaphthalene, quinoline, isoquinoline, methyl 2-furanate, and ethyl 2-furanate; and / or, The ester solvent is selected from one or more of the following: alkyl octanoate, alkyl sebacate, alkyl stearate, alkyl benzoate, alkyl phenylacetate, alkyl cinnamate, alkyl oxalate, alkyl maleate, alkyl lactone, and alkyl oleate; and / or, The aromatic ketone solvent is selected from one or more of 1-tetrahydronaphthone, 2-tetrahydronaphthone, 2-(phenylepoxy)tetrahydronaphthone, 6-(methoxy)tetrahydronaphthone, acetophenone, phenylacetone, benzophenone, and their derivatives, wherein the derivatives may be selected from one or more of 4-methylacetophenone, 3-methylacetophenone, 2-methylacetophenone, 4-methylphenylacetone, 3-methylphenylacetone, and 2-methylphenylacetone; and / or, The aromatic ether solvent is selected from one or more of 3-phenoxytoluene, butoxybenzene, p-anisaldehyde dimethyl acetal, tetrahydro-2-phenoxy-2H-pyran, 1,2-dimethoxy-4-(1-propenyl)benzene, 1,4-benzodioxane, 1,3-dipropylbenzene, 2,5-dimethoxytoluene, 4-ethylbenzene, 1,3-dipropoxybenzene, 1,2,4-trimethoxybenzene, 4-(1-propenyl)-1,2-dimethoxybenzene, 1,3-dimethoxybenzene, glycidyl phenyl ether, dibenzyl ether, 4-tert-butylanisole, trans-p-propenylanisole, 1,2-dimethoxybenzene, 1-methoxynaphthalene, diphenyl ether, 2-phenoxymethyl ether, 2-phenoxytetrahydrofuran, and ethyl-2-naphthyl ether; and / or, Aliphatic ketone solvents are selected from one or more of 2-nonanone, 3-nonanone, 5-nonanone, 2-decanone, 2,5-hexanedione, 2,6,8-trimethyl-4-nonanone, flavone, phorone, isophorone, and di-n-pentyl ketone; and / or, Aliphatic ether solvents are selected from one or more of pentyl ether, hexyl ether, dioctyl ether, ethylene glycol dibutyl ether, diethylene glycol diethyl ether, diethylene glycol butyl methyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol ethyl methyl ether, triethylene glycol butyl methyl ether, tripropylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether; and / or, The mass concentration of N-type self-doped material in the ink is 0.5% to 10%.

7. A light-emitting device, characterized in that, include: Anode and cathode arranged opposite each other; At least two light-emitting units are stacked sequentially between the anode and the cathode; At least one charge generating unit is disposed between two adjacent light-emitting units; The charge generation unit includes an N-type charge generation layer and a P-type charge generation layer stacked together. The N-type charge generation layer is disposed near the anode, and the P-type charge generation layer is disposed near the cathode. The N-type charge generation layer is made of the ink described in any one of claims 1 to 6, or includes an N-type self-doped material with carrier transport function.

8. The light-emitting device according to claim 7, characterized in that, The material of the P-type charge generation layer includes a hole transport material and a P-type doped material, wherein the P-type doped material is selected from at least one of PEDOT:PSS, PEDOT:PSS-PFI, NDP-9, NDP-2, F4-TCNQ, F6-TCNNQ, HATCN, tetrafluorotetracyanoquinone dimethyl ether, 7,7,8,8-tetracyano-p-benzodiquinone dimethyl ether, pentanebenzene, CuPc, WO3, MoO3, NiO, V2O5, CuO, WS2, and MoS2. The hole transport material is selected from 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)benzidine), N,N'-bis(3-methylphenyl)-N,N'-bis(phenyl)spiro, N,N'- At least one of the following: bis(4-(N,N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine, 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, and spiron NPB.

9. The light-emitting device according to claim 7, characterized in that, Each of the light-emitting units in the light-emitting device independently includes a light-emitting layer; The material of the light-emitting layer is an organic light-emitting material or a quantum dot light-emitting material; the organic light-emitting material includes one or more of the following: TBPe fluorescent material, TTPX fluorescent material, TBRb fluorescent material, DBP fluorescent material, TADF material, TTA material, polymers containing BN covalent bonds, hybrid local charge transfer excited state materials, excitocomplex light-emitting materials, polyacetylene and its derivatives, poly(p-phenylene) and its derivatives, polythiophene and its derivatives, and polyfluorene and its derivatives; the quantum dot light-emitting material includes one or more of the following: single-structure quantum dots, core-shell structure quantum dots, and perovskite semiconductor materials, wherein the shell of the core-shell structure quantum dots comprises one or more layers;The materials of the single-structure quantum dots, the core material of the core-shell structure quantum dots, and the shell material of the core-shell structure quantum dots are each independently selected from one or more of group II-VI compounds, group IV-VI compounds, group III-V compounds, and group I-III-VI compounds. The group II-VI compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, and HgSeT. One or more of the following compounds: e, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, and HgZnSTe, wherein the group IV-VI compounds include SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, and SnSe. Te, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe, and SnPb, wherein the III-V compound comprises one or more of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, and Al One or more of PSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, and InAlPSb, wherein the group I-III-VI compounds include one or more of CuInS2, CuInSe2, and AgInS2;The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The perovskite semiconductor material includes doped or undoped inorganic perovskite semiconductors or organic-inorganic hybrid perovskite semiconductors. The general structural formula of the inorganic perovskite semiconductor is AMX3, where A is cesium, M includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X is a halogen, including one or more of chlorine, bromine, and iodine. The general structural formula of the organic-inorganic hybrid perovskite semiconductor is BM'X'3, where B includes CH3(CH2). n-2 NH3 or [NH3(CH2)] n [NH3], where n≥2, M' includes one or more of lead, tin, copper, nickel, cadmium, manganese, cobalt, iron, chromium, ytterbium, and europium, and X' is a halogen, including one or more of chlorine, bromine, and iodine.

10. The light-emitting device according to claim 9, characterized in that, Each light-emitting unit in the light-emitting device further includes a hole functional layer and / or an electron functional layer independently. The hole functional layer is disposed on the side of the light-emitting layer near the anode, and the electron functional layer is disposed on the side of the light-emitting layer near the cathode. When each light-emitting unit includes a hole functional layer, a light-emitting layer, and an electron functional layer stacked sequentially, the N-type charge generation layer is disposed between the electron functional layer and the P-type charge generation layer of the light-emitting unit near the anode, and the P-type charge generation layer is disposed between the hole functional layer and the N-type charge generation layer of the light-emitting unit near the cathode. The hole functional layer comprises a hole injection layer and / or a hole transport layer. The material of the hole injection layer is selected from at least one of poly(3,4-vinyldioxythiophene):poly(styrenesulfonic acid), copper phthalocyanine, titanium phthalocyanine, 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4'-tris[2-naphthylphenylamino]triphenylamine, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, transition metal oxides, or transition metal chalcogenides. The transition metal oxide is selected from NiO. x MoO x WO x CrO x or CuO x At least one of the following, wherein the transition metal chalcogenide compound is selected from MoS x MoSe x WS x 、WSe x or CuS x At least one of the following; and / or, the material of the hole transport layer is selected from poly(9,9-dioctylfluorene-CO-N-(4-butylphenyl)diphenylamine), 3-hexyl-substituted polythiophene, poly(9-vinylcarbazole), poly[bis(4-phenyl)(4-butylphenyl)amine], poly(N,N'-bis(4-butylphenyl)-N,N'-diphenyl-1,4-phenylenediamine-CO-9,9-dioctylfluorene), 4,4',4”-tris(carbazole-9-yl)triphenylamine, 4,4'-bis( At least one of the following: 9-carbazole)biphenyl, N,N'-diphenyl-N,N'-di(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine, poly(3,4-vinyldioxythiophene):poly(styrenesulfonic acid), doped or undoped graphene, C60, NiO, MoO3, WO3, V2O5, CrO3, CuO, or p-type gallium nitride; and / or, The electronic functional layer includes an electron injection layer and / or an electron transport layer, wherein the materials of the electron transport layer and the electron injection layer independently include at least one of inorganic materials and organic compounds; the inorganic material is selected from one or more of the following: doped or undoped zinc oxide, barium oxide, aluminum oxide, titanium oxide, tin oxide, tantalum oxide, zirconium oxide, nickel oxide, lithium titanium oxide, zinc aluminum oxide, zinc manganese oxide, zinc tin oxide, zinc lithium oxide, indium tin oxide, cadmium sulfide, zinc sulfide, molybdenum sulfide, tungsten sulfide, copper sulfide, zinc tin sulfide, indium phosphide, gallium phosphide, copper indium sulfide, copper gallium sulfide, and barium titanate; the doped elements include aluminum and magnesium. One or more of lithium, manganese, yttrium, lanthanum, copper, nickel, zirconium, cerium, and gadolinium, wherein the organic compound comprises one or more of 4,6-bis(3,5-bis(pyridin-3-yl)phenyl)-2-methylpyrimidine, 2,9-dimethyl-4,7-biphenyl-1,10-o-diazaphenanthroline, 4,7-diphenyl-1,10-phenanthroline, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 8-hydroxyquinoline aluminum, 8-hydroxyquinoline lithium, bis(2-methyl-8-hydroxyquinoline-N1,O8)-(1,1'-biphenyl-4-hydroxy)aluminum, and ion-conjugated polyelectrolytes, and / or, The anode and the cathode each independently comprise a doped metal oxide electrode, a composite electrode, a graphene electrode, a carbon nanotube electrode, a metal element electrode, or an alloy electrode. The doped metal oxide electrode is made of one or more of the following materials: indium-doped tin oxide, zinc-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, aluminum-doped magnesium oxide, and cadmium-doped zinc oxide. The composite electrode comprises AZO / Ag / AZO, AZO / APC / AZO, ITO / Ag / ITO, ITO / APC / ITO, IZO / Ag / IZO, and IZO. The metal element electrode is made of one or more of Ag, Ni, Pt, Au, Ir, Cu, Mo, Al, Ca, Mg, and Ba, and the alloy electrode includes an Au:Mg alloy electrode or an Ag:Mg alloy electrode.

11. A display device, characterized in that, The display device includes the light-emitting device according to any one of claims 8 to 10.

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