Organic compounds, organic layers, and organic electroluminescent devices

Abstract

The application discloses an organic compound, an organic layer and an organic electroluminescent device, relates to the technical field of organic electroluminescent materials, and discloses an organic compound, a structural formula of which is shown in formula I: in the formula I, A is selected from substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl; B is selected from hydrogen, substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C3-C30 heteroaryl, and the structure of at least one of A and B is shown in formula II: the organic compound of the application comprises the structures shown in formula I and formula II, wherein the alkyl group contained in formula I can increase the power supply capacity of the molecule, so as to balance the electron-deficient state of the molecule, thereby achieving the effect of improving the stability of the molecule, meanwhile, formula II is connected with formula I, which not only can improve the electron mobility and the ability of balancing electrons and holes, but also can enhance the film-forming property and the thermal stability of the molecule. Therefore, when the organic compound of the application is applied to the organic electroluminescent device, the luminous efficiency and the service life of the device can be significantly improved, and the working voltage can be reduced.

Description

Technical Field

[0001] This application relates to the field of organic electroluminescent materials technology, specifically to an organic compound, an organic layer, and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) possess characteristics such as high brightness, a wide range of material choices, low driving voltage, and all-solid-state active light emission. They also offer advantages such as high definition, wide viewing angle, and high-speed response for smooth animation display. Their light-emitting mechanism is as follows: driven by an external electric field, electrons and holes are injected from the cathode and anode into the organic electron transport layer and hole transport layer, respectively. They recombine in the organic light-emitting layer to generate excitons, which then radiatively transition back to the ground state and emit light.

[0003] Since Kodak's CWTang et al. revealed that organic thin-film devices could emit light with high brightness, numerous researchers in the OLED industry have conducted extensive research and advancements in its applications, leading to the widespread use of OLEDs in various main displays and significant progress in their practical application. Despite the rapid progress in OLED research, it still cannot meet market demands, thus requiring the continuous development of new materials with even higher performance to satisfy market needs. Summary of the Invention

[0004] The purpose of this application is to provide an organic compound, an organic layer, and an organic electroluminescent device to improve the performance of organic electroluminescent devices.

[0005] To achieve the above objectives, the first aspect of this application provides an organic compound with the structural formula shown in Formula I: In Formula I, A is selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups; B is selected from hydrogen, substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups, and the structure of at least one of A and B is shown in Formula II:

[0006] In Formula II: L1 is selected from single-bonded, substituted, or unsubstituted groups or combinations thereof:

[0007]

[0008] Wherein, X1 is selected from O, S, CR1R2; X2 and X3 are independently selected from O, S, NR3, CR4R5; R1 to R5 are independently selected from substituted or unsubstituted C1 to C30 alkyl, substituted or unsubstituted C3 to C30 cycloalkyl, substituted or unsubstituted C1 to C30 heteroalkyl, substituted or unsubstituted C2 to C30 heterocycloalkyl, substituted or unsubstituted C6 to C30 aryl, substituted or unsubstituted C3 to C30 heteroaryl, or formed a ring with adjacent atoms; Ar1 ​​and Ar2 are independently selected from substituted or unsubstituted C6 to C30 aryl, substituted or unsubstituted C3 to C30 heteroaryl; * represents a linking site.

[0009] A second aspect of this application provides an organic layer comprising any of the organic compounds described above.

[0010] A third aspect of this application provides an organic electroluminescent device, including a first electrode, a second electrode, and the aforementioned organic layer located between the first electrode and the second electrode.

[0011] The organic compounds of this application comprise structures shown in Formula I and Formula II. The alkyl groups in Formula I increase the electron-emitting capacity of the molecule, balancing the electron-deficient state and thus improving molecular stability. Formula II, connected to Formula I, not only enhances electron mobility and balances the electron-hole relationship but also strengthens the molecule's film-forming properties and thermal stability. Therefore, applying the organic compounds of this application to organic electroluminescent devices can significantly improve the device's luminous efficiency and lifetime while reducing the operating voltage. Attached Figure Description

[0012] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein:

[0013] Figure 1 This is a schematic diagram of the structure of the organic electroluminescent device prepared in Example 21 of this application. Detailed Implementation

[0014] The following description provides specific application scenarios and requirements for this application, intended to enable those skilled in the art to make and use the content of this application. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can 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 rather to the widest scope consistent with the claims.

[0015] The following is a detailed explanation of some terms used in this application:

[0016] Substitution or non-substitution: refers to substitution by one or more substituents, or no substitution at all. Substituents in substitution may be selected from, for example, deuterium, halogen, cyano, nitro, hydroxyl, carbonyl, ester, imide, amino, phosphine oxide, alkoxy, aryloxy, alkylthio, arylthio, alkylsulfonyl, arylsulfonyl, silyl, boron, alkyl, alkenyl, aryl, aralkyl, arylenyl, alkylaryl, alkylamine, aralkylamine, heteroarylamine, arylamine, arylphosphine, heterocyclic; or substituted by a substituent that links two or more of the substituents listed above. For example, "substituent linking two or more substituents" may include biphenyl, i.e., biphenyl may be aryl, or a substituent linking two phenyl groups. When substituted by two or more substituents, adjacent substituents may also fused or linked to form a ring.

[0017] Aryl group: No particular limitation is made; the aryl group can be monocyclic or polycyclic. In some embodiments, monocyclic aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, tetraphenyl, and pentaphenyl. Polycyclic aryl groups include, but are not limited to, naphthyl, anthracene, phenanthryl, pyrene, perylene, and fluorenyl. The fluorenyl group can be substituted, such as 9,9'-dimethylfluorenyl or 9,9'-dibenzofluorenyl. Furthermore, two of the substituents can combine with each other to form a spirocyclic structure, such as 9,9'-spirodifluorenyl or spirofluorenoxanthyl.

[0018] The above description of aryl groups can be applied to aryl groups in the following categories: aryloxy, arylthio, arylsulfonyl, arylphosphinyl, aralkyl, arylalkylamine, arylenyl, alkylaryl, arylamine, and arylheteroarylamine.

[0019] Heteroaryl groups: Containing one or more of B, N, O, P, S, Si, and Se as heteroatoms. Heteroaryl groups include, but are not limited to, pyridinyl, pyrrolyl, pyrimidinyl, pyridazinyl, furanyl, thiopheneyl, imidazolyl, pyrazolyl, azole, isozolyl, thiazolyl, isothiazolyl, triazolyl, diazolyl, thiadiazolyl, dithiazolyl, tetrazolyl, pyranyl, thiaranyl, pyrazinyl, azinyl, thiazolyl, dioxazinyl, dioxazinyl, triazinyl, tetraazinyl, quinolinyl, isoquinolinyl, quinolinyl, quinazolinyl, quinoxalinyl, naphridinyl, acridineyl, xanthyl, phenanthridineyl, diazanaphthyl, triazaindenyl, indoleyl, dihydroindoleyl, nitro-indenyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinyl Pyrazinyl, benzothiazolyl, benzoxazolyl, benzoimidazolyl, benzothiophene, benzofuranyl, dibenzothiophene, dibenzofuranyl, carbazoleyl, benzocarbazoleyl, dibenzocarbazoleyl, indolocarbazoleyl, indocarbazoleyl, phenazinyl, imidazopyridyl, phenazinyl, phenanthrinyl, phenthiazolyl, imidazopyridyl, imidazophenanthrinyl, benzoimidazoquinazolinyl, benzoimidazophenanthrinyl, spiro[fluorene-9,9'-oxazanthracene], phenylbinaphthyl, dinaphthofuranyl, naphthobenzofuranyl, dinaphthiophene, naphthobenzothiophene, triphenylphosphine oxide, triphenylborane, etc.

[0020] The above description of heteroaryl groups can be applied to heteroaryl groups in heteroaryl amines and aryl heteroaryl amines.

[0021] Alkyl groups: may be straight-chain or branched, including but not limited to methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, 5-methylhexyl.

[0022] The above description of alkyl groups can also be used for alkyl groups in aralkyl, aralkylamine, alkylaryl, and alkylamine groups.

[0023] Heteroalkyl: An alkyl group containing heteroatoms, and the number of carbon atoms is not particularly limited. In some embodiments, heteroalkyl groups include, but are not limited to, alkoxy, alkylthio, alkylsulfonyl, etc. Alkoxy groups can be, for example, methoxy, ethoxy, n-propoxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentoxy, neopentoxy, isopentoxy, n-hexyloxy, 3,3-dimethylbutoxy, 2-ethylbutoxy, n-octoxy, n-nonoxy, n-decoxy, benzyloxy, p-methylbenzyloxy, etc. Alkylthio groups can include, for example, 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, benzylthio, etc.

[0024] Cycloalkyl groups: also known as cyclic saturated hydrocarbon groups, 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, cyclooctyl, etc.

[0025] Heterocyclic alkyl groups: cycloalkyl groups containing heteroatoms, for example: wait.

[0026] The first aspect of this application provides an organic compound having the structural formula shown in Formula I: In Formula I, A is selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups; B is selected from hydrogen, substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups, and the structure of at least one of A and B is shown in Formula II:

[0027] In the organic compounds of this application, the alkyl groups represented by Formula I can increase the electron-emitting capacity of the molecule, thereby balancing the electron-deficient state of the molecule and thus improving the molecular stability. Based on this, the triazine structure represented by Formula II is connected to the main structure of Formula I, which can effectively improve the electron mobility and electron-hole balance of the molecule, and enhance the film-forming properties and thermal stability of the molecule. Therefore, when the organic compounds of this application are used as electron transport materials, they can significantly improve the luminous efficiency and lifetime of the device, and reduce the operating voltage.

[0028] In Formula II, L1 is selected from single bonds, substituted or unsubstituted groups or combinations of groups:

[0029]

[0030] Wherein, X1 is selected from O, S, CR1R2. X2 and X3 are independently selected from O, S, NR3, CR4R5. R1 to R5 are independently selected from substituted or unsubstituted C1 to C30 alkyl groups, substituted or unsubstituted C3 to C30 cycloalkyl groups, substituted or unsubstituted C1 to C30 heteroalkyl groups, substituted or unsubstituted C2 to C30 heterocycloalkyl groups, substituted or unsubstituted C6 to C30 aryl groups, substituted or unsubstituted C3 to C30 heteroaryl groups, or formed a ring with adjacent atoms. Ar1 and Ar2 are independently selected from substituted or unsubstituted C6 to C30 aryl groups and substituted or unsubstituted C3 to C30 heteroaryl groups. * represents a linking site.

[0031] In some preferred embodiments, A is selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups. More preferably, A is selected from substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, and substituted or unsubstituted dibenzofuranyl groups. When substituted, the substituent can be alkyl, aryl, or heteroaryl. For example, the substituent can be methyl, ethyl, dimethyl, phenyl, naphthyl, biphenyl, or dibenzofuranyl. The structure of B is shown in Formula II, where L1 is selected as described above, and when L1 is substituted, the substituent is selected from C1-C10 alkyl groups, C6-C20 aryl groups, and C3-C20 heteroaryl groups. For example, the substituent can be selected from methyl, dimethyl, ethyl, phenyl, naphthyl, biphenyl, dibenzofuranyl, etc. X1 can be selected from O, S, or CR1R2, and when X1 is selected from CR1R2, R1 and R2 are independently selected from substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C20 aryl groups, substituted or unsubstituted C3-C20 heteroaryl groups, or cyclic groups formed by bonding with adjacent atoms. As an example, R1 and R2 are independently selected from methyl, phenyl, etc., or cyclic groups formed by bonding. or X2 and X3 are independently selected from O and S. Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups, wherein the substituent is selected from alkyl, aryl, or heteroaryl. More preferably, Ar1 and Ar2 are independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, or substituted or unsubstituted dibenzofuranyl.

[0032] In some other preferred embodiments, B is selected from hydrogen, substituted or unsubstituted C6-C20 aryl groups, and substituted or unsubstituted C3-C20 heteroaryl groups. More preferably, B is selected from hydrogen, substituted or unsubstituted phenyl groups, substituted or unsubstituted naphthyl groups, and substituted or unsubstituted dibenzofuranyl groups. More preferably, B is hydrogen. The structure of A is shown in Formula II, and in Formula II: L1 is selected as described above, and when L1 is substituted, the substituent is selected from C1-C10 alkyl groups, C6-C20 aryl groups, and C3-C20 heteroaryl groups. As an example, the substituent in the case of substitution can be selected from methyl, dimethyl, ethyl, phenyl, naphthyl, biphenyl, dibenzofuranyl, etc. X1 can be selected from O, S, or CR1R2, and when X1 is selected from CR1R2, R1 and R2 are independently selected from substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C20 aryl groups, substituted or unsubstituted C3-C20 heteroaryl groups, or cyclic groups formed by bonding with adjacent atoms. As an example, R1 and R2 are independently selected from methyl, phenyl, etc., or cyclic groups formed by bonding. X2 and X3 are independently selected from O and S. Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups, wherein the substituent is selected from alkyl, aryl, or heteroaryl. More preferably, Ar1 and Ar2 are independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, or substituted or unsubstituted dibenzofuranyl.

[0033] In some further preferred embodiments, the structures of A and B are both as shown in Formula II, and in Formula II:

[0034] Each time L1 appears, it is independently selected from the following groups, whether single-bonded, substituted, or unsubstituted: Furthermore, the substituents used in substitution are selected from C1-C10 alkyl groups, C6-C20 aryl groups, and C3-C20 heteroaryl groups, such as methyl, dimethyl, ethyl, phenyl, naphthyl, biphenyl, dibenzofuranyl, etc. X1 can be selected from O, S, or CR1R2, and when X1 is selected from CR1R2, R1 and R2 are independently selected from substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C20 aryl groups, substituted or unsubstituted C3-C20 heteroaryl groups, or can form a ring with adjacent atoms. As an example, R1 and R2 are independently selected from methyl, phenyl, etc., or can form a ring with adjacent atoms. Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups, wherein the substituent is selected from alkyl, aryl, or heteroaryl. More preferably, Ar1 and Ar2 are independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, or substituted or unsubstituted dibenzofuranyl.

[0035] In some preferred embodiments, the structural formula of the organic compound is selected from the group consisting of:

[0036]

[0037]

[0038] Wherein, X1 is selected from O, S, CR1R2, and R1 and R2 are independently selected from C1 to C10 alkyl groups or bonded to form the following structures: X2 and X3 are independently selected from O and S; Ar2 is selected from the following groups or combinations of groups: phenyl, naphthyl, biphenyl, dibenzofuranyl.

[0039] In some specific embodiments, the organic compound is selected from the group consisting of:

[0040]

[0041] A second aspect of this application provides an organic layer comprising any of the aforementioned organic compounds.

[0042] A third aspect of this application provides an organic electroluminescent device, comprising a first electrode, a second electrode, and the aforementioned organic layer located between the first electrode and the second electrode. As an example, the first electrode is an anode, and the second electrode is a cathode, wherein the cathode may be one or more layers. The organic layer may be a single-layer structure or a multilayer tandem structure with two or more organic layers laminated together. The organic layer may include an electron transport layer, and the electron transport layer comprises the aforementioned organic compound.

[0043] In some embodiments, the organic layer may further 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 injection layer, etc.

[0044] In some specific embodiments, the organic electroluminescent device is constructed from one of the following:

[0045] (1) An organic electroluminescent device includes an anode, a hole injection layer, a first hole transport layer, a light-emitting layer, a first electron transport layer, and a cathode stacked in sequence, that is, anode / hole injection layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode. The structure of each device will be expressed in this simplified way below.

[0046] (2) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode.

[0047] (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.

[0048] (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.

[0049] (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.

[0050] (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.

[0051] (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.

[0052] (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.

[0053] (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.

[0054] (10) Anode / hole injection layer / hole transport layer / electron blocking layer / light emission layer / electron transport layer / electron injection layer / cathode.

[0055] (11) Anode / hole injection layer / first hole transport layer / second hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / cathode.

[0056] (12) Anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / electron transport layer / cathode.

[0057] (13) Anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode.

[0058] (14) Anode / hole injection layer / hole transport layer / light emission layer / electron transport layer / electron injection material / cathode.

[0059] The light emission direction of the organic electroluminescent device can be either from the anode side or the cathode side. When emitting light from the cathode side, the difference from structures (1) to (14) is that a covering layer needs to be added to the cathode surface.

[0060] The following describes some specific functional layers in the organic electroluminescent device.

[0061] Substrate:

[0062] The substrate is generally located below the anode. The substrate can be made of plastic or glass, and can be rigid or flexible. The substrate has a driving unit that can drive the corresponding pixel to emit light.

[0063] anode:

[0064] Organic EL (Organic Electro-Luminescence) devices typically require the anode to have good conductivity, a smooth surface, and be resistant to cracking. They also have certain requirements for work function, mainly to match the hole injection layer and achieve the hole injection effect.

[0065] When using a top-emitting method (cathode-side light emission), the anode is a metal compound with a work function of 4.2 eV or higher, such as indium tin oxide, tin oxide, indium zinc oxide, gold, silver, platinum, copper, carbon nanotubes, carbon nanowires, graphene, etc. The thickness is 10 nm to 200 nm, preferably 10 nm to 50 nm. A reflective electrode is placed below the anode (near the substrate end). The reflective electrode is generally made of metal or metal alloy, such as silver, copper, aluminum, gold, or alloys of these metals with other metals. The reflective electrode has high reflectivity, requiring a reflectivity of over 90%, and its thickness is typically between 100 nm and 500 nm, preferably in the range of 80 nm to 150 nm.

[0066] When bottom-emitting (substrate-side light emission) is used, the anode is a metal compound with a work function of 4.2 eV or higher, such as indium tin oxide, tin oxide, indium zinc oxide, gold, silver, platinum, copper, carbon nanotubes, carbon nanowires, graphene, etc. The thickness is 10 nm to 1 μm, preferably 50 nm to 200 nm.

[0067] The anode can be made by forming a thin film from the electrode material using methods such as vapor deposition, sputtering, or coating.

[0068] Hole injection layer:

[0069] The thickness of the hole injection layer is typically 3 nm to 30 nm. The hole injection layer uses a mixture of P-type and hole transport materials. The purpose of using P-type materials is to accept holes from the anode and transfer them to the hole transport material. The weight percentage of P-type materials in the hole injection layer is typically 0.5% to 10%. When the weight percentage 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 must not exceed 0.3 eV. When the weight percentage 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 must not exceed 0.5 eV. When the weight percentage 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 must not exceed 1 eV.

[0070] P-type materials can be metal oxides, such as molybdenum oxide, vanadium oxide, and tungsten oxide; they can also be organic compounds, such as 4,4',4”-((1E,1'E,1”E)-cyclopropane-1,2,3-trimethylenetris(cyanoformyl))tris(2,3,5,6-tetrafluorobenzyl) (PD1, CAS No.: 1224447-88-4), tetracyanoquinone dimethyl (TCNQ), 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinone dimethyl (F4-TCNQ), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), and are not limited to these. The hole transport material paired 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.

[0071] Second hole transport layer:

[0072] The thickness of the second hole transport layer is generally 5nm to 150nm, and it often uses compounds containing aryl amines, such as monoaryl amines or polyaryl amines.

[0073] First hole transport layer:

[0074] The thickness of the first hole transport layer is typically 3nm to 500nm. When there is no second hole transport layer, the thickness of the first hole transport layer is typically 40nm to 150nm; when there is a second hole transport layer, the thickness of the first hole transport layer is typically 3nm to 500nm.

[0075] Electron blocking layer:

[0076] The electron blocking layer can simultaneously possess both hole transport and electron blocking functions. Furthermore, the higher triplet excitation energy level of the electron blocking layer can confine excitons generated in the emissive layer within it, thereby improving the device's luminous efficiency.

[0077] Emissive layer:

[0078] The material of the light-emitting layer generally includes a host material and a dopant material, wherein the content of the host material is greater than that of the dopant material. Optionally, the mass percentage of the dopant material in the light-emitting layer is 1% to 20%.

[0079] Cavity blocking layer:

[0080] To enhance the balance between hole and electron concentrations, a hole blocking layer is inserted to balance carrier concentration and prevent exciton quenching. Typically, the hole blocking layer is located between the emitting layer and the electron transport layer, and the hole blocking layer material must meet conditions such as high stability, good film-forming properties, and a sufficiently high highest molecular occupied orbital.

[0081] First electron transport layer:

[0082] The thickness of the first electron transport layer can typically be 3nm–40nm, 3nm–10nm, 10nm–20nm, 20nm–30nm, 30nm–40nm, or 20nm–40nm. When there is no second electron transport layer, the thickness of the first electron transport layer is typically 20nm–40nm; when there is a second electron transport layer, the thickness of the first electron transport layer is typically 20nm–30nm. The first electron transport layer is in direct contact with the emitting layer, and therefore, similar to the first hole transport layer, it also undergoes electronic changes during electron transport, leading to increased molecular vibration and deformation. Furthermore, the interaction between the excitons of the emitting layer and the polarons of the electron transport material can easily generate reactive free radicals, which can damage the electron transport material. Electron transport materials can be single compounds or mixtures with other metal compounds, such as Liq.

[0083] Second electron transport layer:

[0084] The thickness of the second electron transport layer is generally 10 nm to 40 nm. The material of the second electron transport layer may include a mixture of organic electron transport materials and metal compounds, or a mixture of organic electron transport materials and metals.

[0085] When organic electron transport materials are mixed with metal compound materials, such as alkali metal compounds, alkaline earth metal compounds, and rare earth metal compounds, more specifically, they can be mixed with lithium metal compounds, calcium metal compounds, Mg metal compounds, samarium metal compounds, ytterbium metal compounds, etc., and even more specifically, they can be mixed with lithium 8-hydroxyquinoline, lithium fluoride, magnesium fluoride, ytterbium fluoride, calcium fluoride, etc. When used in combination with metal compounds, the mass percentage of the organic electron transport material can be 20%–80%, 20%–40%, 40%–60%, or 60%–80%, etc.

[0086] When organic electron transport materials are used in combination with metals, such as alkali metals, alkaline earth metals, and rare earth metals, or more specifically, with lithium metal, magnesium metal, calcium metal, ytterbium metal, and samarium metal, the mass ratio of the organic electron transport material can be 80%–99%, 80%–89%, 89%–99%, 80%–85%, 85%–90%, 90%–95%, or 95%–99%, etc.

[0087] Electron injection layer:

[0088] The electron injection layer can lower the potential barrier for electrons to be injected from the cathode into the organic layer, improve electron injection efficiency, and thus optimize device performance. The selection of materials for the electron injection layer needs to consider its work function matching with the cathode material, and can be selected from alkali metals, alkaline earth metals, rare earth metals, or their inorganic or coordination compounds.

[0089] Charge generation layer:

[0090] When a single-layer light-emitting device is used, holes and electrons are injected from the anode and cathode respectively, eliminating the need for a charge generation layer. When using double or multiple light-emitting layers, a charge generation layer is required between the light-emitting layers to achieve charge generation, injection, and transport. This charge generation layer is located between the two light-emitting layers and is typically composed of two P / N type materials. The P-type material is selected from the hole injection materials mentioned earlier, while the N-type material is a mixture of organic electron transport materials and metals. The organic electron transport layer material is selected from the second electron transport layer mentioned earlier, and the metal is selected from alkali metals, alkaline earth metals, and rare earth metals. More specifically, examples include lithium, magnesium, calcium, ytterbium, and samarium. When organic electron transport materials are mixed with metals, the mass percentage of the organic electron transport material can be 80%–99%, 80%–89%, 89%–99%, 80%–85%, 85%–90%, 90%–95%, or 95%–99%, etc.

[0091] cathode:

[0092] The cathode requires materials with good electrical conductivity and a smooth surface. To improve electron injection capability, materials with a low work function are typically chosen. Cathode materials can be single-layer, double-layer, or multi-layer cathodes, generally made of metals or metal alloys. For single-layer cathodes, 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 metal 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 increase electron injection capability. The cathode layer farther from the light-emitting side is mainly used to improve conductivity, and generally uses silver, copper, aluminum, gold, or alloys of these metals with other metals, such as alloys with rare earth metals, alkali metals, or 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 into a thin film using methods such as vapor deposition or sputtering.

[0093] When light comes out from the anode side, the cathode must be opaque, and a cathode with a thickness greater than 100 nm can be deposited. When light comes out from the cathode side, the cathode must be transparent, with a transmittance greater than 40% and a thickness of 10 nm to 20 nm.

[0094] Overlay:

[0095] When light exits from the cathode side, photons resonate with electrons in the cathode metal, reducing the light extraction efficiency. Adding a capping layer on the side of the cathode furthest from the light-emitting layer can reduce this effect and effectively improve the light efficiency. When adding a capping layer, a capping layer material with high refractive index and low absorption coefficient should be used directly. For example, a material with a refractive index greater than 1.9 and an absorption rate less than 0.01% at a wavelength of 460 nm is preferred, a material with a refractive index greater than 2.0 and an absorption rate less than 0.01% at a wavelength of 460 nm is preferred, and a material with a refractive index greater than 2.1 and an absorption rate less than 0.01% at a wavelength of 460 nm is even more preferred.

[0096] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Unless otherwise specified, the reagents and raw materials used can be purchased commercially. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional methods and conditions, or conditions recommended by the manufacturer, or the product instructions shall be followed. Unless otherwise stated, all percentages are weight percentages.

[0097] The initial raw materials and solvents used in the following examples were purchased from Sinopharm, and some commonly used OLED intermediates were purchased from domestic OLED intermediate manufacturers; various palladium catalysts were purchased from Sigma-Aldrich. HPLC data were determined using a Shimadzu LC20AD high-performance liquid chromatograph; LC-MS (liquid chromatography-mass spectrometry) was performed on a Waters Corporation H-class+SQD2 instrument.

[0098] Synthesis Examples

[0099] Example 1

[0100] Synthesis of Compound 1

[0101]

[0102] Under an argon atmosphere, 43.8 g (100 mmol) of compound 1-A, 35.3 g (100 mmol) of compound 1-B, 787 mg (1 mmol%) of XPhos Pd G3, 50 mL (300 mmol) of 1.5 M potassium phosphate, and 1000 mL of tetrahydrofuran (THF) were added to a reaction vessel, and the mixture was refluxed and stirred for 18 hours. After cooling to room temperature, 800 mL of water was added, and a large amount of solid precipitated. The solid was filtered, and the filter cake was washed three times with water and dried under vacuum. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate / hexane) to give 44.8 g of compound 1, yield 63%, HPLC purity 99.9%. LC MS: M / Z 710.34 (M+).

[0103] Examples 2-20

[0104] The product compounds shown in Table 1 were prepared according to the synthesis method of Example 1.

[0105] Table 1. Raw materials and product compounds

[0106]

[0107]

[0108]

[0109] Device Examples

[0110] The structural formulas of the organic layer compounds used in the following examples and comparative examples are as follows:

[0111]

[0112] Example 21

[0113] refer to Figure 1This embodiment provides a method for fabricating an organic electroluminescent device, including the following steps:

[0114] The glass substrate 100 with a transparent indium tin oxide (ITO) (10Ω / sq) 110 was ultrasonically cleaned with acetone, ethanol and distilled water in sequence, and then treated with ozone plasma for 15 minutes.

[0115] After mounting the glass substrate 100 with the anode 110 on the substrate holder of the vacuum vapor deposition equipment, the system pressure is controlled at 10. -6 Then, HAT-CN with a thickness of 10 nm, TAPC with a thickness of 40 nm and TCTA with a thickness of 10 nm are sequentially deposited on the anode 110, which serve as hole injection layer 120, hole transport layer 130 and electron blocking layer 140, respectively.

[0116] Compound RH-1 and compound RD were co-deposited on electron blocking layer 140 at a mass ratio of 94:6 to form a 40 nm light-emitting layer 150 (EML).

[0117] Compound 1 of this application with a thickness of 30 nm is deposited on the light-emitting layer 150 as an electron transport layer 160 (ETL);

[0118] A 1 nm thick LiF layer is deposited on the electron transport layer 160 as an electron injection layer 170.

[0119] Finally, an 80 nm thick layer of Al is deposited on the electron injection layer 170 as the cathode 180, and the device is encapsulated using a glass encapsulation cover 190.

[0120] Examples 22-40

[0121] Except that, when forming the electron transport layer 160, compounds 2 to 20 of this application are used to replace compound 1, the organic electroluminescent device is fabricated using the same method as in Example 21.

[0122] Comparative Examples 1-2

[0123] Except that when forming the electron transport layer 160, compound 1 was replaced with compound ETL-1 and compound ETL-2 respectively, the organic electroluminescent device was fabricated using the same method as in device example 21.

[0124] The devices in each set of examples and comparative examples were produced and tested in the same batch. The operating voltage and current efficiency of the devices were tested using a computer-controlled Keithley 2400 test system at a test current of 10 mA / cm². 2 The LT95 lifetime of the device was tested under dark conditions using a Fostar lifetime measurement system equipped with a power supply and a photodiode as the detection unit, with a test current of 10 mA / cm.2 The operating voltage, current efficiency, and LT95 lifetime of the device in Comparative Example 1 are all set to 1, and the performance test results are shown in Table 2.

[0125] Table 2 Device performance test results

[0126]

[0127]

[0128] Referring to Table 2, compared to Comparative Example 1, the application of the compound in Comparative Example 2 to an organic electroluminescent device resulted in an improved device lifetime, but the improvement was not significant. However, the use of the compound of this application resulted in a significant improvement in device lifetime. This is because the compound of this application contains alkyl groups in its molecular structure, which increases the molecule's electron-donating capacity, balances the electron-deficient state of the molecule, and thus improves the molecule's stability. Simultaneously, the combination of this alkyl group with the triazine structure not only improves the material's electron mobility and electron-hole balance but also further enhances the molecule's film-forming properties and thermal stability. Therefore, the device lifetime is significantly improved, and efficiency and operating voltage are also greatly enhanced. In contrast, the compound in Comparative Example 2 also introduces a carbazole group into its molecular structure. While the carbazole group provides strong electron-donating capacity, which is beneficial for improving device lifetime, it also reduces the molecule's mobility. Furthermore, introducing too many electron-donating centers weakens the molecule's stability, thus limiting the improvement in device lifetime.

[0129] In summary, the organic compounds of this application have excellent performance and can effectively improve device performance when applied to organic electroluminescent devices, thus showing good application prospects in the field of organic electroluminescence.

[0130] The above description of the embodiments is intended to enable those skilled in the art to understand and apply this application. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, this application is not limited to the embodiments described herein, and any 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. An organic compound, characterized in that, Its structural formula is shown in Formula I: In Formula I, A is selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups; B is selected from hydrogen, substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups, and the structure of at least one of A and B is shown in Formula II: In Equation II: L1 is selected from the following groups or combinations of groups, whether single-bonded, substituted, or unsubstituted: Among them, X1 is selected from O, S, CR1R2; X2 and X3 are independently selected from O, S, NR3, CR4R5; R1 to R5 are independently selected from substituted or unsubstituted C1 to C30 alkyl groups, substituted or unsubstituted C3 to C30 cycloalkyl groups, substituted or unsubstituted C1 to C30 heteroalkyl groups, substituted or unsubstituted C2 to C30 heterocycloalkyl groups, substituted or unsubstituted C6 to C30 aryl groups, substituted or unsubstituted C3 to C30 heteroaryl groups, or formed into a ring with adjacent atoms; Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C30 aryl groups and substituted or unsubstituted C3-C30 heteroaryl groups; * Represents a connection point.

2. The organic compound according to claim 1, characterized in that, A is selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups, and the structure of B is as shown in Formula II; or, B is selected from hydrogen, substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups, and the structure of A is as shown in Formula II; in Formula II: When L1 is substituted, the substituent is selected from C1-C10 alkyl, C6-C20 aryl, and C3-C20 heteroaryl; When X1 is selected from CR1R2, R1 and R2 are independently selected from substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C20 aryl groups, substituted or unsubstituted C3-C20 heteroaryl groups, or cyclic groups formed by bonds with adjacent atoms. X2 and X3 are independently selected from O and S.

3. The organic compound according to claim 2, characterized in that, The structure of B is shown in Formula II, and A is selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl.

4. The organic compound according to claim 2, characterized in that, The structure of A is shown in Formula II; B is selected from hydrogen, substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted dibenzofuranyl.

5. The organic compound according to claim 1, characterized in that, The structures of A and B are both as shown in Formula II, and in Formula II: each time L1 appears, it is independently selected from the following groups, whether single-bonded, substituted, or unsubstituted: Furthermore, the substituents used in the substitution process are selected from C1-C10 alkyl groups, C6-C20 aryl groups, and C3-C20 heteroaryl groups; wherein, when X1 is selected from CR1R2, R1 and R2 are independently selected from substituted or unsubstituted C1-C10 alkyl groups, substituted or unsubstituted C6-C20 aryl groups, substituted or unsubstituted C3-C20 heteroaryl groups, or formed a ring with adjacent atoms.

6. The organic compound according to any one of claims 1 to 5, characterized in that, Ar1 and Ar2 are independently selected from substituted or unsubstituted C6-C20 aryl groups and substituted or unsubstituted C3-C20 heteroaryl groups, and the substituents when substituted are selected from alkyl, aryl, and heteroaryl groups; preferably, Ar1 and Ar2 are independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, and substituted or unsubstituted dibenzofuranyl.

7. The organic compound according to claim 1, characterized in that, The structural formula of the organic compound is selected from the following group: Wherein, X1 is selected from O, S, CR1R2, and R1 and R2 are independently selected from C1 to C10 alkyl groups or bonded to form the following structures: X2 and X3 are independently selected from O and S; Ar2 is selected from the following groups or combinations of groups: phenyl, naphthyl, biphenyl, dibenzofuranyl.

8. The organic compound according to claim 7, characterized in that, The organic compounds are selected from the following group:

9. An organic layer, characterized in that, Includes the organic compounds described in any one of claims 1 to 8.

10. An organic electroluminescent device, characterized in that, It includes a first electrode, a second electrode, and an organic layer as described in claim 9 located between the first electrode and the second electrode.

11. The organic electroluminescent device according to claim 10, characterized in that, The organic layer includes an electron transport layer, and the electron transport layer comprises an organic compound according to any one of claims 1 to 8.

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