Covering layer, film layer structure and organic light-emitting device

Abstract

The invention discloses a covering layer, a film layer structure and an organic light-emitting device, and relates to the technical field of organic light-emitting materials, the covering layer comprises a compound shown as a formula I and / or a formula II: # imgabs0 # imgabs1 #, wherein Ar1 and Ar2 are the same or different and are independently selected from substituted or unsubstituted C6-C24 aryl groups and substituted or unsubstituted C3-C24 heteroaryl groups; the Ak1 and the Ak2 are the same or different; the alkyl groups are independently selected from the group consisting of substituted or unsubstituted C1-C30 alkyl groups, substituted or unsubstituted C1-C30 heteroalkyl groups, substituted or unsubstituted C3-C30 cycloalkyl groups, substituted or unsubstituted C2-C30 heterocycloalkyl groups, substituted or unsubstituted C3-C30 cycloalkyl carbonyl groups, substituted or unsubstituted C1-C30 alkylamino groups, substituted or unsubstituted C1-C30 heteroalkylamino groups, and substituted or unsubstituted C3-C30 cycloalkyl amino groups; and a substituted or unsubstituted C2-C30 heterocyclic alkyl amino group. The compound shown in the formula I and / or the formula II can reduce the refractive index of the covering layer, improve the stripping adhesive force between the covering layer and the cathode and improve the glass transition temperature of the covering layer.

Description

Technical Field

[0001] The present application relates to the technical field of organic light-emitting materials, and in particular to a covering layer, a film structure and an organic light-emitting device. Background Art

[0002] Organic light-emitting devices (OLEDs) are widely used in various main display screens, and their practical application has made significant progress. Despite rapid progress in organic electroluminescence research, many challenges remain, such as the need to improve external quantum efficiency (EQE). For OLEDs, the device's luminescence quantum efficiency (EQE) reflects a comprehensive range of factors and is a key indicator of device quality.

[0003] At present, some organic light-emitting materials have been used commercially due to their excellent performance. They use amine derivatives with specific structures with high refractive index or materials that meet specific parameter requirements as covering layer materials to improve light extraction efficiency and color purity. However, the problem of balancing luminous efficiency and color purity has not yet been solved, especially in the preparation of blue light-emitting elements.

[0004] In this regard, researchers have discovered that stacking a high-refractive index layer and a low-refractive index layer in the cover layer can improve light extraction efficiency and color purity (see Chinese authorized patent CN111316461B). However, existing low-refractive index materials generally contain fluorine atoms. While the introduction of fluorine atoms and their derivatives can lower the material's refractive index, it also weakens the bond between the material and the device's cathode (Ag), making it prone to delamination. Furthermore, the introduction of fluorine atoms weakens the intermolecular forces in the compound, thereby lowering the material's glass transition temperature (Tg), shortening the device's service life. Summary of the Invention

[0005] The technical problem solved by the present application is to improve the peeling adhesion between the cover layer and the cathode and the glass transition temperature of the cover layer while maintaining a relatively low refractive index.

[0006] In order to solve the above technical problems, the first aspect of the present application provides a covering layer comprising a compound represented by Formula I and / or Formula II: In Formula I, Ar1 and Ar2 are the same or identical and are independently selected from substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C3-C24 heteroaryl; in Formula II, Ak1 and Ak2 are the same or different and are independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 heteroalkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C2-C30 heterocycloalkyl, substituted or unsubstituted C3-C30 cycloalkylcarbonyl, substituted or unsubstituted C1-C30 alkylamino, substituted or unsubstituted C1-C30 heteroalkylamino, substituted or unsubstituted C3-C30 cycloalkylamino, substituted or unsubstituted C2-C30 heterocycloalkylamino, or are bonded to adjacent atoms to form a ring; any hydrogen on Formula I and / or Formula II may be optionally substituted by deuterium.

[0007] The second aspect of the present application provides a film layer structure located on the side of the cathode of an organic light-emitting device away from the anode, the film layer structure including a first film layer adjacent to the cathode, and the first film layer contains the compound shown in the above-mentioned formula I and / or formula II.

[0008] A third aspect of the present application provides an organic light-emitting device, comprising an anode, an organic layer, a cathode, and the above-mentioned covering layer or the above-mentioned film layer structure stacked in sequence.

[0009] The compound shown in formula I and / or formula II included in the covering layer and film structure of the present application uses cyclobutanediimide structure as the parent core, wherein the introduction of the imide group provides heteroatoms (O and N), which are rich in lone pairs of electrons and can form weak interactions with the cathode material molecules. When the covering layer or film structure is adjacent to the cathode of the organic light-emitting device, it has a large peeling adhesion between the cathode, making it difficult to peel between the layers. In addition, the hydrogen bonds that may exist in the molecules of such compounds can enhance the intermolecular force, which on the one hand cooperates with the weak interaction between the cathode material, so that the covering layer and film structure have a large peeling adhesion between the cathode; on the other hand, after the intermolecular force is enhanced, the Tg of the covering layer and film structure is improved. At the same time, in the parent core of the compound, a cycloalkyl group is used as the central ring, which can effectively reduce the refractive index of the compound molecule.

[0010] The compounds represented by Formula I and Formula II may or may not contain fluorine atoms / fluorine-containing groups. When the compounds represented by Formula I and Formula II contain fluorine atoms / fluorine-containing groups, the aforementioned synergistic effect can improve the technical problems of easy peeling between the existing fluorine-containing materials and the cathode and unsatisfactory Tg. When the compounds represented by Formula I and Formula II do not contain fluorine atoms / fluorine-containing groups, not only can the technical problems of easy peeling between the cathode and unsatisfactory Tg caused by fluorine be effectively avoided, but also costs can be significantly reduced, providing a more environmentally friendly solution.

[0011] When the cover layer and film structure contain compounds of Formula I and / or Formula II, the ultraviolet absorption of these compounds is blue-shifted, ensuring that the light emitted by the device is not absorbed by the cover layer or film structure, thereby improving the light extraction efficiency of the device. Replacing the cover layer containing existing fluorine-containing materials with a cover layer or film structure containing compounds of Formula I and / or Formula II can significantly improve the luminous efficiency and color purity of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The following figures describe in detail exemplary embodiments disclosed in this application. Identical reference numerals denote similar structures in several views of the drawings. Those skilled in the art will appreciate that these embodiments are non-limiting, exemplary embodiments, and that the drawings are for illustration and description purposes only and are not intended to limit the scope of this application. Other embodiments may also achieve the same inventive intent as described in this application. It should be understood that the drawings are not drawn to scale. Among them:

[0013] Figure 1 This is a schematic structural diagram of the organic light-emitting device prepared in Example 29 of the present application. DETAILED DESCRIPTION

[0014] The following description provides specific application scenarios and requirements of the present application, with the purpose of enabling those skilled in the art to make and use the content of this application. Various local modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but is intended to be of the widest scope consistent with the claims.

[0015] While existing fluorine-containing overlays can improve device luminous efficiency and color purity, they suffer from weak peel adhesion to the cathode and a low glass transition temperature, resulting in reduced device lifespan. To address this, the inventors conducted extensive research and discovered that applying cyclobutanediimide compounds to the overlay can reduce the refractive index of the overlay. Furthermore, these compounds exhibit strong peel adhesion to the cathode and a higher Tg.

[0016] Specifically, the present application provides a covering layer comprising a compound represented by Formula I and / or Formula II:

[0017] In this document, the term "covering layer" is broadly defined to encompass both literal covering structures and similar layered structures that actually function as covering structures. Even if such structures are referred to by other names, such as a flat layer or a cathode contact layer, as long as they achieve the purposes of this application, they fall within the scope of the covering layer as defined herein.

[0018] In Formula I, Ar1 and Ar2 are the same or different and are independently selected from substituted or unsubstituted C6-C24 aryl groups and substituted or unsubstituted C3-C24 heteroaryl groups.

[0019] Unless otherwise specified, the terms "substituted" or "unsubstituted" as used herein refer to substitution with one or more substituents, or to unsubstituted substituents, selected from the group consisting of deuterium, a halogen group, a cyano group, a nitro group, a hydroxyl group, a carbonyl group, an ester group, an imide group, an amino group, a phosphino group, an alkoxy group, an aryloxy group, a sulfone group, a sulfoxide group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group, a silyl group, a boron group, an aryl group, a heteroaryl group, an aralkyl group, an aralkenyl group, an alkylaryl group, an alkylamino group, an aralkylamino group, a heteroarylamino group, an arylamino group, an arylphosphino group, a heterocyclic group, and a carboxyl derivative group; or substitution with a substituent that connects two or more of the substituents listed above. For example, a "substituent that connects two or more substituents" may include a biphenyl group, i.e., a biphenyl group may be an aryl group, or a substituent that connects two phenyl groups. When substituted with two or more substituents, adjacent substituents may also be bonded to form a ring. For example, bonding to form a ring may be achieved by chemical bonding or by fusion.

[0020] Unless otherwise specified, the aryl groups described herein may be monocyclic or polycyclic. Monocyclic aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, quaterphenyl, and pentphenyl. Polycyclic aryl groups include, but are not limited to, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, perylenyl, and fluorenyl. Fluorenyl groups may be substituted, such as 9,9'-dimethylfluorenyl and 9,9'-dibenzofluorenyl. Furthermore, two substituents may combine to form a spirocyclic structure, such as 9,9'-spirobifluorenyl.

[0021] The above description of the aryl group can be applied to the aryl group in the aryloxy group, arylthio group, arylsulfonyl group, arylphosphino group, arylalkyl group, arylalkylamino group, arylalkenyl group, alkylaryl group, arylamino group and arylheteroarylamino group.

[0022] Unless otherwise specified, the heteroaryl group described herein refers to an aryl group containing one or more of B, N, O, P, S, Si and Se as heteroatoms, including but not limited to pyridyl, pyrrolyl, pyrimidinyl, pyridazinyl, furanyl, thienyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, dithiazolyl, tetrazolyl, pyrazinyl, thiazinyl, triazinyl, tetrazinyl, quinolyl, isoquinolyl, quinolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, acridinyl, phenanthridinyl, naphthyridinyl, triazaindenyl, indolyl, indolizinyl, phthalazinyl 1,2'-dibenzo[1,2'-oxa]anthracene], benzophenanthryl, benzophenanthryl, benzophenanthridine ...

[0023] The above description of the heteroaryl group can be applied to the heteroaryl group in the heteroarylamine group and the arylheteroarylamine group.

[0024] In Formula II, Ak1 and Ak2 are the same or different and are independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 heteroalkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C2-C30 heterocycloalkyl, substituted or unsubstituted C3-C30 cycloalkylcarbonyl, substituted or unsubstituted C1-C30 alkylamino, substituted or unsubstituted C1-C30 heteroalkylamino, substituted or unsubstituted C3-C30 cycloalkylamino, substituted or unsubstituted C2-C30 heterocycloalkylamino, or bonded to adjacent atoms to form a ring.

[0025] Unless otherwise specified, the alkyl groups described herein may be straight-chain or branched, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl (tBu), sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, methyl-substituted isobutyl, methyl-substituted tert-butyl, etc. In this document, when an alkyl group is mentioned without specifying whether it is straight-chain or branched, the expression implicitly covers all isomeric forms of the alkyl group, including straight-chain structures and branched structures. For example, "dodecyl" includes n-dodecyl (straight-chain) and all branched dodecyl isomers (such as 2-methylundecyl, 3,5-dimethyldecyl, etc.).

[0026] The above description of alkyl groups also applies to aralkyl groups, aralkylamino groups, alkylaryl groups, alkylamino groups (also known as alkylamino groups), and alkyl groups in alcohol groups. Unless otherwise specified, an alkylamino group as described herein refers to a group formed by the connection of an alkyl group and an amino group, such as methylamino and ethylamino. When referring to an alcohol group without specifying whether the alkyl portion is straight-chain or branched, the term implicitly encompasses all carbon chain isomeric forms of the alkyl group. For example, the "pentyl" in "pentanol" encompasses branched structures such as n-pentyl (straight-chain), 2-methylbutyl, 3-methylbutyl, and 2,2-dimethylpropyl. The hydroxyl group can optionally be attached to any carbon atom (including primary, secondary, and tertiary carbon atoms) in the alkyl chain. For example, a pentanol group may be 1-pentanol (hydroxyl group attached to the end of the straight chain), 2-pentanol (hydroxyl group attached to the second carbon atom of the straight chain), or 3-methyl-2-butanol (hydroxyl group attached to a secondary carbon atom of the branched alkyl group).

[0027] Unless otherwise specified, the heteroalkyl groups described herein may be straight-chain or branched alkyl groups containing heteroatoms, including but not limited to alkoxy, alkylthio, and alkylsulfonyl groups. Alkoxy groups include but are not limited to methoxy, ethoxy, n-propyloxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentoxy, neopentoxy, isopentoxy, n-hexyloxy, 3,3-dimethylbutoxy, 2-ethylbutoxy, n-octyloxy, n-nonyloxy, n-decyloxy, benzyloxy, and p-methylbenzyloxy. Alkylthio groups include but are not limited to methylthio, ethylthio, n-propylthio, isopropylthio, isopropylthio, n-butylthio, isobutylthio, tert-butylthio, sec-butylthio, n-pentylthio, neopentylthio, isopentylthio, n-hexylthio, 3,3-dimethylbutylthio, 2-ethylbutylthio, n-octylthio, n-nonylthio, n-decylthio, and benzylthio.

[0028] The above description of heteroalkyl groups also applies to the heteroalkyl groups within heteroalkylamino groups. Unless otherwise specified, heteroalkylamino groups herein refer to groups formed by replacing carbon atoms in the alkyl portion of an alkylamino group with other heteroatoms (e.g., non-carbon atoms such as oxygen, nitrogen, sulfur, and phosphorus) or by inserting heteroatoms into the alkyl chain. Simply put, heteroalkylamino groups contain heteroatoms.

[0029] Unless otherwise specified, the cycloalkyl group described herein is a cyclic saturated hydrocarbon group, such as cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, bicyclo[2.2.1]heptanyl Bicyclo[2.2.2]octyl Cyclooctyl, spiro[4.4]nonyl Adamantyl (Ad), etc. The * appearing in the structural formula herein represents a connection site.

[0030] The above description of cycloalkyl can also be applied to the cycloalkyl in cycloalkylcarbonyl and cycloalkylamino. Unless otherwise specified, the cycloalkylcarbonyl described herein refers to a group formed by connecting a cycloalkyl and a carbonyl (C=O), such as cyclohexylcarbonyl. The cycloalkylamino group described herein refers to a group formed by connecting a cycloalkyl group and an amino group, for example, N-methylcyclohexylamino.

[0031] Unless otherwise specified, the heterocycloalkyl group described herein is a cycloalkyl group containing heteroatoms, such as tetrahydropyranyl. Tetrahydrothiopyranyl wait.

[0032] The above description of heterocycloalkyl groups also applies to the heterocycloalkyl groups in heterocycloalkylamino groups. Unless otherwise specified, heterocycloalkylamino groups as described herein refer to groups formed by replacing carbon atoms in the cycloalkane structure with one or more heteroatoms (e.g., non-carbon atoms such as nitrogen, oxygen, and sulfur) based on cycloalkylamino groups.

[0033] In some preferred embodiments, Ar1 and Ar2 are independently selected from the following substituted or unsubstituted groups: phenyl, biphenyl, naphthyl, phenanthrenyl, anthracenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, spirofluorenyl, spirofluorenyloxanthryl, triphenylene, triazine, phosphorus oxide derivative group, sulfone derivative group, N-phenylphthalimide group, benzophenone group.

[0034] In some preferred embodiments, when Ar1 and / or Ar2 are substituted, the substituents are independently selected from fluorine atoms, fluorine-containing groups, alkyl groups, heteroalkyl groups, alkenyl groups, hydroxyl groups, and the following groups which are substituted or unsubstituted with fluorine atoms or fluorine-containing groups or alkyl groups or heteroalkyl groups or alkenyl groups: phenyl groups, naphthyl groups, pyridyl groups, and phenol groups.

[0035] Unless otherwise specified, the fluorine-containing group herein refers to a chemical group containing fluorine atoms in its structure, which is characterized by the fluorine atoms being bonded to other atoms (such as carbon, oxygen, nitrogen, silicon, phosphorus, boron, etc.) through covalent bonds, including but not limited to fluoroalkyl (e.g., trifluoromethyl (-CF3), perfluorooctyl (-C8F 17) etc.), fluoroaryl (for example, p-fluorophenyl (-C6H4F) etc.), fluorinated heterocyclic group (for example, 2-fluoropyridyl etc.), fluorinated oxy group (for example, trifluoromethoxy (-OCF3) etc.), fluorinated amino group (for example, N-fluoroamino (-NF2) etc.), fluorinated silicon group (for example, trifluoropropylsilyl (-Si(CH2)3CF3) etc.), etc. The alkyl group in the fluoroalkyl group includes C1~C10 alkyl group and C3~C10 cycloalkyl group. The aryl group in the fluoroaryl group includes C6~C12 aryl group. The fluorinated oxy group includes O-fluoroaryl, O-fluoroalkyl and O-fluorocycloalkyl group. The fluorinated amino group includes N-fluoroaryl, N-fluoroalkyl and N-fluorocycloalkyl group. The fluorinated silicon group includes Si-fluoroaryl, Si-fluoroalkyl and Si-fluorocycloalkyl group.

[0036] In some preferred embodiments, Ak1 and Ak2 are independently selected from the following substituted or unsubstituted groups: C1-C20 alkyl, C5-C12 cycloalkyl, C5-C12 cycloalkylcarbonyl, C5-C18 cycloalkylamino.

[0037] In some preferred embodiments, when Ak1 and / or Ak2 are substituted, the substituents are independently selected from fluorine atoms, fluorine-containing groups, hydroxyl groups, and the following groups which are substituted or unsubstituted with fluorine atoms, fluorine-containing groups or hydroxyl groups: C1-C6 alkyl groups, C6-C12 aryl groups, and C3-C12 heteroaryl groups.

[0038] In some preferred embodiments, the Ak1 and Ak2 are independently selected from the following groups which are substituted or unsubstituted by fluorine atoms, fluorine-containing groups or hydroxyl groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, dodecyl, octadecyl, *-(C)n-Ar3, cyclopentyl, cyclohexyl, Adamantyl, (C)n represents an alkyl group having n carbon atoms, and n is selected from an integer of 1 to 6. Ar3 is selected from a substituted or unsubstituted C6-C12 aryl group, or a substituted or unsubstituted C3-C12 heteroaryl group, and when substituted, the substituent is selected from a C6-C12 aryl group or a C3-C12 heteroaryl group.

[0039] In some more preferred embodiments, Ak1 and Ak2 are independently selected from dodecyl, octadecyl, pentanol, cyclopentyl, cyclohexyl, Adamantyl,

[0040] In some preferred embodiments, the compound represented by formula I is selected from the following group:

[0041]

[0042]

[0043] In the above formula, Ar2 is selected from phenyl, naphthyl, phenanthrenyl, dibenzofuranyl, 9,9'-dimethylfluorenyl, carbazolyl, spirofluorenyl, spirofluorenyloxanthryl, phenyl-substituted triazine, phosphorus oxide derivative, sulfone derivative, pyridine-substituted phenyl, naphthalene-substituted phenyl, 9,9'-diphenylfluorenyl, N-phenylphthalimide, benzophenone, hydroxy-substituted biphenyl, phenyl-substituted anthracene. Preferably, Ar2 and Ar1 are the same for ease of synthesis and cost reduction.

[0044] In some preferred embodiments, the compound represented by formula II is selected from the following group:

[0045]

[0046]

[0047] In the above formula, Ak2 is selected from the following groups: Adamantyl, Dodecyl, octadecyl, amyl alcohol. Preferably, in order to facilitate synthesis and reduce costs, Ak1 and Ak2 are the same.

[0048] It should be noted that the connection sites of Ar1, Ar2, Ak1, Ak2 and N in the imide group have little effect on the refractive index and adhesion, so this application does not impose any special restrictions on these connection sites.

[0049] In the compounds shown in Formula I and / or Formula II of the present application, since the imide group provides heteroatoms (O and N), the heteroatoms can form weak interactions with the cathode material molecules, thereby improving the peeling adhesion between the covering layer and the cathode. At the same time, the hydrogen bonds that may exist within the molecules of such compounds will enhance the intermolecular forces, which will further improve the peeling adhesion between the covering layer and the cathode. Therefore, even if fluorine atoms, fluorine-containing groups, alkyl groups, heteroalkyl groups or alkenyl groups are introduced into the molecules of the compounds shown in Formula I and Formula II, it is still possible to maintain a strong grip between the covering layer and the cathode, while further reducing the refractive index.

[0050] In some embodiments, the cover layer comprises one or more of the following compounds:

[0051]

[0052]

[0053] The group C in the above compounds 26 and 2712 H 25 -, group C 18 H 37 - encompasses all isomers corresponding to the number of carbon atoms.

[0054] In some embodiments, any hydrogen on the compounds of Formula I and / or Formula II may be optionally replaced with deuterium.

[0055] The present application also provides a film structure located on the side of the cathode of an organic light-emitting device away from the anode, wherein the film structure includes a first film layer adjacent to the cathode, and the first film layer contains the compound represented by the above-mentioned formula I and / or formula II.

[0056] In some preferred embodiments, the film layer structure further includes a second film layer adjacent to a side of the first film layer away from the cathode, and the refractive index of the second film layer for light with a wavelength of 460 nm is greater than 1.90.

[0057] In the present application, the first film layer has a lower refractive index because it contains the compound shown in Formula I and / or Formula II. It and the second film layer with a higher refractive index together constitute a film layer structure. When it is located on the side of the cathode of the organic light-emitting device away from the anode, it can effectively improve the luminous efficiency and color purity of the device.

[0058] In some preferred embodiments, when refracting light with a wavelength of 460 nm, the refractive index of the first film layer is 1.40 to 1.56. For example, the refractive index of the first film layer may be 1.40, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49, 1.50, 1.51, 1.52, 1.53, 1.54, 1.55, or 1.56, or a specific value in a sub-range consisting of any of the above values. The refractive index of the second film layer is 1.90 to 2.50. For example, the refractive index of the second film layer may be 1.90, 1.95, 2.00, 2.10, 2.15, 2.20, 2.25, 2.30, 2.35, 2.40, 2.45, or 2.50, or a specific value in a sub-range consisting of any of the above values. More preferably, the refractive index of the second film layer is 2.20.

[0059] In some preferred embodiments, the second film layer is formed of at least one of an inorganic compound and an organic compound, wherein the inorganic compound includes at least one of SiOx, SiNy, ZnS, ZnSe, ZrO, and TiO2, and x and y are independently selected from integers of 1 to 4. The organic compound includes at least one of an aromatic amine derivative, a carbazole derivative, a benzimidazole derivative, and a triazole derivative. More preferably, the organic compound includes at least one of the following compounds:

[0060]

[0061] The present application also provides an organic light-emitting device, comprising an anode, an organic layer, a cathode, and the aforementioned covering layer or the aforementioned film layer structure stacked in sequence.

[0062] The organic layer may be a single-layer structure or a multi-layer tandem structure comprising two or more organic layers. The organic layer may include at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. In some preferred embodiments, the organic layer includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer stacked in sequence.

[0063] As an example, the structure of the organic light-emitting device may be selected from one of the following:

[0064] (1) An organic light-emitting device includes an anode, a hole injection layer, a first hole transport layer, a light-emitting layer, a first electron transport layer, a cathode, and a capping layer stacked in sequence, i.e., anode / hole injection layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode / capping layer. This simplified representation of the device structure will be used below.

[0065] (2) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode / covering layer.

[0066] (3) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / cathode / covering layer.

[0067] (4) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / electron injection layer / cathode / covering layer.

[0068] (5) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / second electron transport layer / multilayer cathode / covering layer.

[0069] (6) Anode / hole injection layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / cathode / covering layer.

[0070] (7) Anode / hole injection layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / second electron transport layer / cathode / covering layer.

[0071] (8) Anode / hole injection layer / second hole transport layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / cathode / covering layer.

[0072] (9) Anode / hole injection layer / second hole transport layer / first hole transport layer / first light-emitting layer / carrier generation layer / first hole transport layer / second light-emitting layer / first electron transport layer / second electron transport layer / cathode / covering layer.

[0073] (10) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / electron transport layer / electron injection layer / cathode / covering layer.

[0074] (11) Anode / hole injection layer / first hole transport layer / second hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / cathode / covering layer.

[0075] (12) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / electron transport layer / cathode / covering layer.

[0076] (13) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / cathode / covering layer.

[0077] (14) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode / covering layer.

[0078] The covering layer in the above structures (1) to (14) can also be replaced by the aforementioned film layer structure.

[0079] Some specific functional layers in the organic light-emitting device will be described below.

[0080] Substrate:

[0081] The substrate is generally located below the anode and can be made of plastic or glass, and can be rigid or bendable. A driving unit is provided on the substrate to drive the corresponding pixel to emit light.

[0082] anode:

[0083] The anode usually needs to meet requirements such as good conductivity, smooth surface, and no cracks. At the same time, there are certain requirements for the work function, mainly to be able to match the hole injection layer and exert the hole injection effect.

[0084] When top emission is used (light emitting from the cathode side), the anode uses a metal compound with a work function of 4.2eV or more, such as indium tin oxide alloy, tin oxide, indium zinc oxide, gold, silver, platinum, copper, carbon nanotubes, carbon nanowires, graphene, etc. The thickness is 10nm to 200nm, preferably 10nm to 50nm. A reflective electrode is set below the anode (near the substrate end). The reflective electrode is generally made of metal or metal alloy, such as silver metal, copper metal, aluminum metal, gold metal, or alloys of these metals with other metals. The reflective electrode has a high reflectivity, which is required to be above 90%. The thickness is usually used in the range of 100nm to 500nm, preferably in the range of 80nm to 150nm.

[0085] The anode can be produced by forming an electrode material into a thin film by a method such as vapor deposition, sputtering, or coating.

[0086] The thickness of the hole injection layer can be 3nm to 50nm. The hole injection layer can be a mixture of P-type materials and hole transport materials. The purpose of using the P-type material is to accept holes from the anode and transfer them to the hole transport material. The weight proportion of the P-type material in the hole injection layer is generally 0.5% to 10%. When the weight proportion is 0.5% to 3%, the absolute value of the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the P-type material and the highest occupied molecular orbital (HOMO) energy level of the HTL material shall not exceed 0.3eV. When the weight proportion is 3% to 5%, the absolute value of the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the P-type material and the highest occupied molecular orbital (HOMO) energy level of the HTL material shall not exceed 0.5eV. When the weight proportion is 5% to 10%, the absolute value of the difference between the lowest unoccupied molecular orbital (LUMO) energy level of the P-type material and the highest occupied molecular orbital (HOMO) energy level of the HTL material shall not exceed 1eV.

[0087] The P-type material can be a metal oxide, such as molybdenum oxide, vanadium oxide, tungsten oxide, etc.; it can also be an organic material, such as 4,4',4"-((1E,1'E,1"E)-cyclopropane-1,2,3-trimethylenetris(cyanoformylidene))tris(2,3,5,6-tetrafluorobenzyl) (PD1, CAS No.: 1224447-88-4), tetracyanoquinodimethane (TCNQ), 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinodimethane (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), and is not limited thereto. The hole transport material used in combination with the P-type material can be selected from the material of the second hole transport layer, and can be the same as or different from the material of the second hole transport layer.

[0088] First hole transport layer:

[0089] The thickness of the first hole transport layer is generally 3 nm to 150 nm. When there is no second hole transport layer, the thickness of the first hole transport layer is generally 40 nm to 150 nm; when there is a second hole transport layer, the thickness of the first hole transport layer is generally 3 nm to 40 nm.

[0090] Second hole transport layer:

[0091] The second hole transport layer can be 40nm to 150nm thick and typically uses an aromatic amine compound, either an aromatic monoamine or an aromatic polyamine. The hole transport material is required to have high hole mobility, reduce driving voltage, and a glass transition temperature exceeding 100°C to avoid crystallization at high temperatures.

[0092] Electron blocking layer:

[0093] The electron blocking layer can have both hole transport and electron blocking functions. At the same time, the higher triplet excitation energy level of the electron blocking layer can lock excitons generated in the light-emitting layer in the light-emitting layer, thereby improving the luminous efficiency of the device.

[0094] Luminous layer:

[0095] The materials of the light-emitting layer generally include a host material and a guest dopant material. The content of the host material is greater than that of the guest dopant material. Optionally, the mass percentage of the guest dopant material in the light-emitting layer is 1% to 20%.

[0096] The guest dopant material used as the luminescent material may include a phosphorescent or fluorescent material or a thermally activated delayed fluorescent material. Red, green, and blue light can be selected from the above three types of guest dopant materials. For example, the guest dopant material for the luminescent layer corresponding to the red luminescent unit and the luminescent layer corresponding to the green luminescent unit is a phosphorescent material, while the guest dopant material for the luminescent layer corresponding to the blue luminescent unit is a fluorescent material.

[0097] Or for example, the guest doping material of the light-emitting layer corresponding to the light-emitting unit with red light emission color and the light-emitting layer corresponding to the light-emitting unit with green light emission color is a phosphorescent material, and the guest doping material of the light-emitting layer corresponding to the light-emitting unit with blue light emission color is a phosphorescent material.

[0098] Or for example, the guest doping material of the light-emitting layer corresponding to the light-emitting unit with red light-emitting color and the light-emitting layer corresponding to the light-emitting unit with green light-emitting color is a thermally activated delayed fluorescent material, and the guest doping material of the light-emitting layer corresponding to the light-emitting unit with blue light-emitting color is a fluorescent material.

[0099] Or for example, the guest doping material of the light-emitting layer corresponding to the light-emitting unit with red light-emitting color and the light-emitting layer corresponding to the light-emitting unit with green light-emitting color is a thermally activated delayed fluorescent material, and the guest doping material of the light-emitting layer corresponding to the light-emitting unit with blue light-emitting color is a phosphorescent material.

[0100] In order to reduce the power consumption of the organic light-emitting display panel in the organic electroluminescent device, the guest doping material can be selected to have excellent luminescence performance. 2 The current efficiency is greater than 35cd / A, and the luminous unit with green luminous color has a luminous brightness of 6000cd / m 2 The current efficiency is greater than 100cd / A, and the light-emitting unit with a blue light color has a light brightness of 1000cd / m 2 When the external quantum efficiency is greater than 8%, a suitable guest doping material is selected.

[0101] As the light-emitting host material, one light-emitting host material or two light-emitting host materials can be selected.

[0102] Hole blocking layer:

[0103] To enhance the balance between hole and electron concentrations, a hole-blocking layer is inserted to balance carrier concentrations and prevent exciton quenching. Typically, the hole-blocking layer is located between the light-emitting layer and the electron-transporting layer. The hole-blocking layer material must meet requirements such as high stability, good film-forming properties, and a high maximum molecular orbital.

[0104] First electron transport layer:

[0105] The thickness of the first electron transport layer can be 3nm to 40nm, 3nm to 10nm, 10nm to 20nm, 20nm to 30nm, 30nm to 40nm or 20nm to 40nm, etc. When there is no second electron transport layer, the thickness of the first electron transport layer is generally 20nm to 40nm. When there is a second electron transport layer, the thickness of the first electron transport layer is generally 20nm to 30nm. The first electron transport layer is in direct contact with the light-emitting layer. Therefore, similar to the first hole transport layer, electronic changes will also occur during the electron transport process, resulting in increased molecular vibration and molecular deformation. The excitons of the light-emitting layer will also interact with the polarons of the electron transport material. This interaction can easily generate active free radicals and destroy the electron transport material. The electron transport material can be a single compound or mixed with other metal compounds, such as Liq.

[0106] Second electron transport layer:

[0107] The thickness of the second electron transport layer may be 10 nm to 40 nm, and the material of the second electron transport layer may include a mixture of an organic electron transport material and a metal compound, or a mixture of an organic electron transport material and a metal.

[0108] When the organic electron transport material is mixed with a metal compound material, for example, with an alkali metal compound, an alkaline earth metal compound, or a rare earth metal compound, more specifically, with a lithium metal compound, a calcium metal compound, a magnesium metal compound, a samarium metal compound, or a ytterbium metal compound, and more specifically, with lithium 8-hydroxyquinoline, lithium fluoride, magnesium fluoride, ytterbium fluoride, or calcium fluoride. When mixed with the metal compound, the weight proportion of the organic electron transport material can be 20% to 80%, 20% to 40%, 40% to 60%, or 60% to 80%.

[0109] When the organic electron transport material is mixed with a metal, for example, with an alkali metal, an alkaline earth metal, or a rare earth metal, more specifically, with lithium metal, magnesium metal, calcium metal, ytterbium metal, samarium metal, etc., when mixed with a metal, the mass proportion of the organic electron transport material can be 80% to 99%, 80% to 89%, 89% to 99%, 80% to 85%, 85% to 90%, 90% to 95%, or 95% to 99%, etc.

[0110] Charge generation layer:

[0111] When using a single-layer light-emitting device, holes and electrons are injected from the anode and cathode, respectively, eliminating the need for a charge generation layer. When using a dual-layer or multi-layer light-emitting device, a charge generation layer is required between the light-emitting layers to achieve charge generation, injection, and transport. The charge generation layer is located between the two light-emitting layers and is typically composed of a P / N-type dual-layer material. The P-type material is selected from the hole-injection materials mentioned above, and the N-type material is a mixture of an organic electron transport material doped with a metal. The organic electron transport layer material is selected from the second electron transport layer mentioned above, and the metal is selected from alkali metals, alkaline earth metals, and rare earth metals, with lithium, magnesium, calcium, ytterbium, and samarium being more specific examples. When the organic electron transport material is mixed with the metal, the weight proportion of the organic electron transport material can range from 80% to 99%, 80% to 89%, 89% to 99%, 80% to 85%, 85% to 90%, 90% to 95%, or 95% to 99%, etc.

[0112] Electron injection layer:

[0113] The electron injection layer (EIL) is typically a functional material layer located between the cathode and the electron transport layer. Its primary function is to facilitate efficient electron injection from the cathode into the organic functional layer. The cathode is typically composed of materials such as metals, but the significant energy level difference between organic materials and metals can hinder electron injection. The EIL exists to reduce this energy barrier, allowing electrons to smoothly enter the organic material system from the cathode.

[0114] Common electron injection layer materials include alkali metal compounds (such as LiF, etc.), metal oxides (such as Cs2CO3, etc.) and some organic small molecules or polymer materials.

[0115] cathode:

[0116] The cathode requires a material with good electrical conductivity and surface flatness. To improve electron injection, materials with a low work function are generally selected. The cathode material can be a single-layer cathode, or a double-layer or multi-layer cathode, typically made of a metal or metal alloy. For a single-layer cathode, silver, copper, aluminum, gold, or alloys of these metals with other metals, such as rare earth metals, alkali metals, and alkaline earth metals, can be used. Examples include magnesium-indium alloys, magnesium-aluminum alloys, aluminum-potassium alloys, aluminum-scandium-potassium alloys, magnesium-silver alloys, silver-ytterbium alloys, and silver-samarium alloys. If a double-layer cathode is used, the cathode layer closer to the light-emitting layer can be made of alkali metals, alkaline earth metals, or rare earth metals, such as lithium, calcium, magnesium, and ytterbium, to enhance electron injection. The cathode layer farther from the light-emitting layer, primarily to enhance conductivity, can typically be made of silver, copper, aluminum, or gold, or alloys of these metals with other metals, such as rare earth metals, alkali metals, and alkaline earth metals. Examples include magnesium-indium alloys, magnesium-aluminum alloys, aluminum-potassium alloys, aluminum-scandium-potassium alloys, magnesium-silver alloys, silver-ytterbium alloys, and silver-samarium alloys. The cathode can also be formed as a thin film by methods such as evaporation and sputtering.

[0117] Covering:

[0118] When light exits the cathode, photons resonate with electrons in the cathode metal, reducing light extraction efficiency. Adding a suitable cover layer to the cathode can reduce this effect, effectively improving light efficiency and achieving a more balanced light extraction efficiency and viewing angle for red, green, and blue light. The cover layer can be single or multi-layer.

[0119] In some preferred embodiments, two covering layers are used, and the total thickness can be 50nm to 90nm, for example: 50nm, 55nm, 57nm, 59nm, 62nm, 64nm, 67nm, 68nm, 70nm, 75nm, 77nm, 79nm, 80nm, 82nm, 85nm, 88nm, 90nm, etc.

[0120] In some preferred embodiments, the covering layer close to the cathode side is a low-refractive-index covering layer, and the thickness may be 5 nm to 40 nm, for example: 5 nm, 7 nm, 10 nm, 12 nm, 15 nm, 18 nm, 20 nm, 22 nm, 25 nm, 27 nm, 30 nm, 32 nm, 34 nm, 36 nm, 38 nm, 40 nm, etc.

[0121] In some preferred embodiments, the covering layer away from the cathode side adopts a high refractive index covering layer, and the thickness can be 35nm to 85nm, for example: 35nm, 40nm, 43nm, 45nm, 48nm, 50nm, 55nm, 57nm, 59nm, 62nm, 64nm, 67nm, 68nm, 70nm, 75nm, 77nm, 79nm, 80nm, 82nm, 85nm, etc.

[0122] The technical solutions of the present application will be described clearly and completely below in conjunction with the examples of the present application. Unless otherwise specified, the reagents and raw materials used can be purchased through commercial channels. The experimental methods in the following examples that do not specify specific conditions are usually determined in accordance with national standards. If there are no corresponding national standards, then according to general international standards, conventional methods and conditions, or according to the conditions recommended by the manufacturer, or according to the product specifications.

[0123] The starting materials and solvents in the following examples were purchased from Sinopharm, and some commonly used OLED intermediates and other products were purchased from domestic OLED intermediate manufacturers. HPLC data were measured using a Shimadzu LC 20AD high-performance liquid phase analyzer. LC-MS (liquid chromatography-mass spectrometry) was performed on a Waters Corporation H-class+SQD2 instrument.

[0124] Compound Preparation Examples

[0125] Example 1

[0126] Preparation of compound 1

[0127]

[0128] Dianhydride 1-A (19.6 g, 100 mmol) and acetic acid (250 mL) were placed in a reaction flask, cooled to 5°C in an ice bath, and 1-B (20.46 g, 220 mmol) was slowly added. After addition, the mixture was heated to 130°C and allowed to react for 4 hours. The reaction mixture was then slowly poured into 250 mL of water, resulting in the precipitation of a large amount of solid. The mixture was filtered, and the filter cake was rinsed with water. The solid was recrystallized from ethanol, filtered, and dried. 30.10 g of a white solid was obtained, with an 87% yield and 99.9% HPLC purity. The product was confirmed to be the desired product, with LCMS: M / Z 346.10 (M+).

[0129] Example 2 to Example 28

[0130] With reference to the preparation method of Example 1, compounds 2 to 28 shown in the following table were prepared.

[0131] Table 1 Reactants and products

[0132]

[0133]

[0134]

[0135] 90° peel performance test

[0136] The coating is performed according to the following structure: ITO substrate (40mm*40mm) / Ag (200nm) / compound film layer (1200nm). The material of the compound film layer is selected from compounds 1 to 28, CPL-1, and CPL-3 of the present application. For the molecular structures of CPL-1 and CPL-3, please refer to the device preparation example.

[0137] One side of the test tape (Model: 3M681) was adhered to the coating layer and rolled evenly 10 times with a roller. The other side of the tape was clamped with a fixture and tested at a speed of 200 mm / min. After the measurement began, the first 5 mm of the tape was disregarded. A 2 mm length was then peeled off from the ITO substrate, and three parallel tests were performed. The average of the adhesion values ​​was taken and set as the peel adhesion value. The test results are shown in Table 2.

[0138] Table 2 Peeling performance test results

[0139]

[0140]

[0141] As shown in Table 2, compared with compound CPL-1 and compound CPL-3, the peeling adhesion between compounds 1 to 28 of the present application and the cathode material is significantly improved. The covering layer containing the compound can form a strong adhesion between the cathode and is not easy to fall off.

[0142] Tg test

[0143] The samples of compounds 1 to 28, CPL-1, and CPL-3 of the present application were tested using a differential scanning calorimeter DSC (TA Instruments, Inc., USA, model DSC25) to determine their Tg. The test results are shown in Table 3.

[0144] Table 3 Tg test results

[0145]

[0146]

[0147] As shown in Table 3, compared with compound CPL-1 and compound CPL-3, compounds 1 to 28 of the present application have higher Tg, and the covering layer prepared from the compounds has good thermodynamic reliability, which is beneficial to improving the life of the device.

[0148] Device preparation example

[0149] Example 29

[0150] refer to Figure 1 The method for preparing an organic light-emitting device in this embodiment includes the following steps:

[0151] (1) After ultrasonically washing the alkali-free glass 1 in isopropyl alcohol for 15 minutes, the glass was treated with ultraviolet ozone in the atmosphere for 30 minutes. Then, a 100 nm silver (Ag) film and a 10 nm ITO film (not distinguished in the figure) were sequentially formed on the alkali-free glass 1 using a radiometric method to form a reflective anode 2.

[0152] (2) The reflective anode 2 was subjected to a 10-minute ultraviolet ozone washing treatment, and a hole injection layer 3 (NPD and F4-TCNQ with a weight ratio of 97:3, 50 nm), a hole transport layer 4 (NPD, 80 nm), a blue light-emitting layer 5 (BH and BD with a weight ratio of 97:3, 20 nm), an electron transport layer 6 (Alq3, 35 nm) and an electron injection layer 7 (LiF, 1 nm) were sequentially deposited on the reflective anode 2 by vacuum evaporation. Mg and Ag (weight ratio of 10:1, 15 nm) were then co-evaporated as a semi-transparent cathode 8.

[0153] (3) Compound 1 prepared in Example 1 was evaporated on the semi-transparent cathode 8 to form a first film layer 91 with a thickness of 10 nm, and compound CPL-2 was evaporated on the first film layer 91 to form a second film layer 92 with a thickness of 50 nm.

[0154] (4) In a glove box with a dry nitrogen atmosphere, an alkali-free glass sealing plate was packaged with an epoxy resin adhesive to produce an organic light-emitting device.

[0155] Examples 30 to 56

[0156] An organic light-emitting device was prepared using the same method as in Example 29, except that Compounds 2 to 28 prepared in the aforementioned Examples were used instead of Compound 1 when forming the first film layer 91 .

[0157] Comparative Example 1

[0158] The only difference from Example 29 is that the first film layer 91 is not provided.

[0159] Comparative Example 2

[0160] The only difference from Example 29 is that the second film layer 92 is not provided.

[0161] Comparative Example 3

[0162] The only difference from Example 29 is that the material of the first film layer 91 is compound CPL-1.

[0163] Comparative Example 4

[0164] The only difference from Example 29 is that the material of the first film layer 91 is compound CPL-3.

[0165] The compounds involved in the above device preparation example are as follows:

[0166]

[0167] Device performance test

[0168] The refractive index of the cover layer at a wavelength of 460 nm was measured using ellipsometry (JA Woollam Co. Inc M-2000). At room temperature and pressure, a 10 mA / cm 2 The luminance and color purity of the device were tested using a luminance meter (CS1000, Konica Minolta Co., Ltd.) with a DC current of 100 nm. The luminous efficiency and color purity shown in Table 4 were obtained from the test results.

[0169] Table 4 Luminous efficiency and color purity results

[0170]

[0171]

[0172] In Table 4, n1 refers to the refractive index of the first film layer for light with a wavelength of 460 nm, and n2 refers to the refractive index of the second film layer for light with a wavelength of 460 nm. Comparison of Examples 29 to 56, Comparative Example 1, and Comparative Examples 3 to 4 demonstrates that Compounds 1 to 28 of the present application can effectively reduce the refractive index of the film layer.

[0173] Furthermore, the results of Comparative Examples 1 and 2 show that when the second film layer with a higher refractive index or the first film layer with a lower refractive index is used alone, the device's luminous efficiency is low and the color purity is not high. Although Comparative Examples 3 and 4 employ both the first and second film layers, which improves the luminous efficiency of the devices, the color purity of the devices is still low. However, when the material of the second film layer remains unchanged and the compound of the present application is used instead of the existing fluorine-containing material to form the first film layer, the device's luminous efficiency and color purity are improved, resulting in a device with both high luminous efficiency and high color purity.

[0174] In summary, when the compound represented by Formula I and / or Formula II of the present application is used to prepare the covering layer of the organic light-emitting device, it is possible to improve the peeling adhesion between the covering layer and the cathode and the Tg of the covering layer while maintaining a low refractive index. Furthermore, the compound is used to prepare a first film layer, and a high refractive index material is used to prepare a second film layer on the first film layer to form a film structure. When used as the covering layer of the organic light-emitting device, the luminous efficiency and color purity of the device can be improved at the same time. It can be seen that the compound represented by Formula I and / or Formula II of the present application and the covering layer and film structure containing the compound have significant technical application potential in organic light-emitting devices.

[0175] The above description of the embodiments is intended to facilitate understanding and application of the present application by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without expending any creative effort. Therefore, the present application is not limited to the embodiments described herein, and improvements and modifications made by those skilled in the art based on the disclosure of this application without departing from the scope and spirit of this application are within the scope of this application.

Claims

1. A covering layer, characterized in that: Containing compounds shown in formula I and / or formula II: In Formula I, Ar1 and Ar2 are the same or different and are independently selected from substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C3-C24 heteroaryl; In Formula II, Ak1 and Ak2 are the same or different and are independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 heteroalkyl, substituted or unsubstituted C3-C30 cycloalkyl, substituted or unsubstituted C2-C30 heterocycloalkyl, substituted or unsubstituted C3-C30 cycloalkylcarbonyl, substituted or unsubstituted C1-C30 alkylamino, substituted or unsubstituted C1-C30 heteroalkylamino, substituted or unsubstituted C3-C30 cycloalkylamino, substituted or unsubstituted C2-C30 heterocycloalkylamino, or are bonded to adjacent atoms to form a ring; Any hydrogen in Formula I and / or Formula II may be optionally replaced with deuterium.

2. The covering layer according to claim 1, characterized in that The Ar1 and Ar2 are independently selected from the following substituted or unsubstituted groups: phenyl, biphenyl, naphthyl, phenanthrenyl, anthracenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, spirofluorenyl, spirofluorenyloxanthryl, triphenylene, triazine, phosphorus oxide derivative group, sulfone derivative group, N-phenylphthalimide group, benzophenone group; preferably, the substituent when substituted is selected from fluorine atoms, fluorine-containing groups, alkyl groups, heteroalkyl groups, alkenyl groups, hydroxyl groups, and the following groups substituted or unsubstituted by fluorine atoms or fluorine-containing groups or alkyl groups or heteroalkyl groups or alkenyl groups: phenyl, naphthyl, pyridyl, phenol group.

3. The covering layer according to claim 1, characterized in that Said Ak1 and Ak2 are independently selected from the following substituted or unsubstituted groups: C1-C20 alkyl, C5-C12 cycloalkyl, C5-C12 cycloalkylcarbonyl, C5-C18 cycloalkylamino; preferably, the substituents when substituted are independently selected from fluorine atoms, fluorine-containing groups, hydroxyl groups, and the following groups substituted or unsubstituted by fluorine atoms, fluorine-containing groups or hydroxyl groups: C1-C6 alkyl, C6-C12 aryl, C3-C12 heteroaryl; Preferably, Ak1 and Ak2 are independently selected from the following groups which are substituted or unsubstituted by fluorine atoms, fluorine-containing groups or hydroxyl groups: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, dodecyl, octadecyl, *-(C)n-Ar3, cyclopentyl, cyclohexyl, Adamantyl, Wherein, * represents a linking site; (C)n represents an alkyl group having n carbon atoms, and n is selected from an integer of 1 to 6; Ar3 is selected from a substituted or unsubstituted C6 to C12 aryl group, a substituted or unsubstituted C3 to C12 heteroaryl group, and when substituted, the substituent is selected from a C6 to C12 aryl group, a C3 to C12 heteroaryl group; More preferably, the Ak1 and Ak2 are independently selected from dodecyl, octadecyl, pentanol, cyclopentyl, cyclohexyl, Adamantyl, * represents the attachment site.

4. The covering layer according to claim 1, characterized in that The compound represented by formula I is selected from the following group: wherein Ar2 is selected from phenyl, naphthyl, phenanthrenyl, dibenzofuranyl, 9,9'-dimethylfluorenyl, carbazolyl, spirofluorenyl, spirofluorenyloxanthryl, phenyl-substituted triazine, phosphorus oxide derivative group, sulfone derivative group, pyridine-substituted phenyl, naphthalene-substituted phenyl, 9,9'-diphenylfluorenyl, N-phenylphthalimide group, benzophenone group, hydroxy-substituted biphenyl group, phenyl-substituted anthracene group; preferably, Ar2 and Ar1 are the same; The compound represented by formula II is selected from the following group: Wherein, Ak2 is selected from the following groups: Adamantyl, Dodecyl, octadecyl, pentanol, wherein * represents the attachment site; preferably, Ak1 and Ak2 are the same.

5. The covering layer according to claim 4, characterized in that The covering layer comprises one or more of the following compounds:

6. A film structure located on the side of the cathode away from the anode of an organic light-emitting device, characterized in that: The membrane structure includes a first membrane layer adjacent to the cathode, and the first membrane layer comprises the compound represented by Formula I and / or Formula II according to any one of claims 1 to 5.

7. The film structure according to claim 6, characterized in that: The film layer structure further includes: a second film layer, adjacent to a side of the first film layer away from the cathode, and a refractive index of the second film layer for light with a wavelength of 460 nm is greater than 1.

90.

8. The film structure according to claim 7, characterized in that: When refracting light with a wavelength of 460 nm, the refractive index of the first film layer is 1.40 to 1.56, and the refractive index of the second film layer is 1.90 to 2.

50.

9. The membrane structure according to claim 7 or 8, characterized in that: The second film layer is formed of at least one of an inorganic compound and an organic compound, wherein the inorganic compound includes at least one of SiOx, SiNy, ZnS, ZnSe, ZrO, and TiO2, and x and y are independently selected from integers of 1 to 4; the organic compound includes at least one of an aromatic amine derivative, a carbazole derivative, a benzimidazole derivative, and a triazole derivative; preferably, the organic compound includes at least one of the following compounds:

10. An organic light-emitting device, characterized in that: The invention comprises an anode, an organic layer, a cathode and the covering layer according to any one of claims 1 to 5 or the film layer structure according to any one of claims 6 to 9 stacked in sequence.

11. The organic light-emitting device according to claim 10, characterized in that: The organic layer includes at least one layer of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; Preferably, the organic layer includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer and an electron injection layer stacked in sequence.

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