Organic electroluminescent compound, organic electroluminescent material and organic electroluminescent device

Abstract

The present application discloses an organic electroluminescent compound, an organic electroluminescent material and an organic electroluminescent device, which relate to the field of organic electroluminescent materials, wherein the organic electroluminescent compound has a structural formula as shown in Formula I: #imgabs0#; in Formula I, R1 to R 32 Each is independently selected from hydrogen, deuterium, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms. The organic electroluminescent compound of the present application can significantly improve the device life.

Description

Technical Field

[0001] The present application relates to the technical field of organic electroluminescent materials, and in particular to an organic electroluminescent compound, an organic electroluminescent material and an organic electroluminescent device. Background Art

[0002] Organic light-emitting diodes (OLEDs) use organic materials as semiconductor materials in light-emitting diodes. These organic materials can emit light when current passes through them. Compared with the earlier developed inorganic electroluminescence, OLEDs have many advantages, such as a wide range of material selection, full-color display from blue to red, low driving voltage, high brightness and efficiency, wide viewing angle, fast response speed, relatively simple manufacturing process, low cost, and flexible display. Therefore, OLEDs are generally considered to be the mainstream of the next generation of display devices.

[0003] With the rapid development of organic electroluminescent devices, the market has higher and higher requirements for the performance of organic electroluminescent devices such as service life and luminous efficiency. Therefore, it is still necessary to continuously improve the performance of devices such as service life and luminous efficiency. Summary of the invention

[0004] The technical problem solved by the present application is to increase the service life of the device.

[0005] In order to solve the above technical problems, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides an organic electroluminescent compound, the structural formula of which is shown in Formula I below:

[0007] ;

[0008] In Formula I, R1 to R 32 Each is independently selected from hydrogen, deuterium, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

[0009] In a second aspect, the present application provides an organic electroluminescent material, comprising the above-mentioned organic electroluminescent compound.

[0010] In a third aspect, the present application provides an organic electroluminescent device, comprising the above-mentioned organic electroluminescent compound or the above-mentioned organic electroluminescent material.

[0011] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0012] The molecular structure of the organic electroluminescent compound of the present application contains both a carbazole group and a 1,3,5-triazine structure substituted by a dibenzofuran group, and the nitrogen atom of the carbazole group and the carbon atom of the triazine group are connected to each other through the ortho position of the biphenyl group. This specific group connection method can significantly improve the device life and maintain the voltage and efficiency at a good level.

[0013] Furthermore, the present application unexpectedly achieves an enhancement effect comparable to that of a fully deuterated compound by deuterating specific positions of the organic electroluminescent compound, thereby significantly reducing the cost of deuteration.

[0014] Furthermore, when the organic electroluminescent compound is used as the n-type luminescent host material and the carbazole derivative shown in Formula II is used as the p-type luminescent host material, the device life can be further improved, while the operating voltage can be reduced and the device efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals represent similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting, exemplary embodiments, and the drawings are only used for the purpose of illustration and description, and are not intended to limit the scope of this application. Other embodiments may also accomplish the inventive intent in this application. It should be understood that the drawings are not drawn to scale. Among them:

[0016] Figure 1 The mass spectrum of compound 1 prepared in Example 1 of the present application;

[0017] Figure 2 The chromatogram of compound 1 prepared in Example 1 of the present application;

[0018] Figure 3 The H NMR spectrum of compound 1 prepared in Example 1 of the present application;

[0019] Figure 4 The mass spectrum of compound 2 prepared in Example 2 of the present application;

[0020] Figure 5 The chromatogram of compound 2 prepared in Example 2 of the present application;

[0021] Figure 6 This is the H NMR spectrum of compound 2 prepared in Example 2 of the present application;

[0022] Figure 7 The mass spectrum of compound 3 prepared in Example 3 of the present application;

[0023] Figure 8 The chromatogram of compound 3 prepared in Example 3 of the present application;

[0024] Fig. 9 This is the H NMR spectrum of compound 3 prepared in Example 3 of the present application;

[0025] Fig.10 This is a schematic diagram of the structure of the organic electroluminescent device prepared in Example 4 of the present application. DETAILED DESCRIPTION

[0026] 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 in the present application. It will be apparent to those skilled in the art that various local modifications to the disclosed embodiments are apparent, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the embodiments shown, but to the widest scope consistent with the claims.

[0027] The following is a detailed description of some terms that appear in this application:

[0028] Substituted or unsubstituted: refers to being substituted by one or more substituents, or not substituted, and the substituents when substituted can be selected from the following: deuterium, halogen (such as fluorine), trifluoromethyl, cyano, nitro, hydroxyl, carbonyl, ester, imide, amino, phosphorus oxygen, alkoxy, aryloxy, sulfone, sulfoxide, alkylthio, arylthio, alkylsulfonyl, arylsulfonyl, silyl, boron, alkyl, cycloalkyl, alkenyl, aryl, heteroaryl, aralkyl, aralkenyl, alkylaryl, alkylamino, aralkylamino, heteroarylamino, arylamino, arylphosphino, heterocyclic group, carboxyl derivative group; or substituted by a substituent connecting two or more of the substituents exemplified above. For example, "a substituent connecting two or more substituents" can include biphenyl, that is, the biphenyl can be an aryl group, or a substituent connecting two phenyl groups. When substituted by two or more substituents, adjacent substituents can also be bonded to form a ring. As an example, bonding to form a ring can be achieved by chemical bonding, or by fusion.

[0029] Aryl: There is no particular limitation, and it may be a monocyclic aryl or a polycyclic aryl. Monocyclic aryl includes, but is not limited to, phenyl, biphenyl, terphenyl, quaterphenyl, pentaphenyl, and the like. Polycyclic aryl includes, but is not limited to, naphthyl, anthracenyl, phenanthrenyl, pyrenyl, peryl, fluorenyl, and the like. Fluorenyl may be substituted, such as 9,9'-dimethylfluorenyl, 9,9'-dibenzofluorenyl, and the like. In addition, two of the substituents may be combined with each other to form a spiro ring structure, such as 9,9'-spirobifluorenyl, and the like. The above description of aryl may be applied to aryl in aryloxy, arylsilanyl, arylgermanyl, arylthio, arylsulfonyl, arylphosphino, arylalkyl, arylalkylamine, arylalkenyl, alkylaryl, arylamine, and arylheteroarylamine.

[0030] Heteroaryl: contains one or more of B, N, O, P, S, Si and Se as heteroatoms. Heteroaryl includes, but is not limited to, pyridyl, pyrrolyl, pyrimidinyl, pyridazinyl, furanyl, thienyl, imidazolyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, triazolyl, oxadiazolyl, thiadiazolyl, dithiazolyl, tetrazolyl, pyranyl, thiopyranyl, pyrazinyl, azinyl, thiazinyl, dioxinyl, triazinyl, tetrazinyl, quinolyl, isoquinolyl, quinolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, acridinyl, xanthenyl, phenanthridinyl, naphthyridinyl, triazaindenyl, indolyl, dihydroindole, indolizinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopy ... Pyrazinyl, benzothiazolyl, benzoxazolyl, benzimidazolyl, benzothienyl, benzofuranyl, dibenzothienyl, dibenzofuranyl, carbazolyl, benzocarbazolyl, dibenzocarbazolyl, indolocarbazolyl, indenocarbazolyl, phenazinyl, imidazopyridinyl, phenazinyl, phenanthridinyl, phenanthrolinyl, phenothiazinyl, imidazopyridinyl, imidazophenanthridinyl, benzimidazoquinazolinyl, benzimidazophenanthridinyl, spiro[fluorene-9,9'-xanthene], benzobinaphthyl, dinaphthofuranyl, naphthobenzofuranyl, dinaphthothienyl, naphthobenzothienyl, triphenylphosphine oxide, triphenylborane, etc. The above description of the heteroaryl group can be applied to the heteroaryl groups in the heteroarylamine group and the arylheteroarylamine group.

[0031] Alkyl: may be linear 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. The above description of the alkyl group can also be applied to the alkyl groups in the aralkyl group, alkylgermanyl group, aralkylamino group, alkylaryl group and alkylamino group.

[0032] Cycloalkyl: 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, cyclooctyl, etc.

[0033] Organic electroluminescent material: refers to a material that can be used in an organic electroluminescent device and can contain at least one compound. If necessary, the organic electroluminescent material can be included in any layer constituting the organic electroluminescent device. For example, it can be included in at least one layer of the following: hole injection layer, hole transport layer, hole auxiliary layer, luminescence auxiliary layer, electron blocking layer, luminescent layer, electron buffer layer, hole blocking layer, electron transport layer and electron injection layer, etc. For example, the organic electroluminescent material can be a hole injection material, a hole transport material, a hole auxiliary material, a luminescence auxiliary material, an electron blocking material, a luminescent material (including a main material and a doping material), an electron buffer material, a hole blocking material, an electron transport material, an electron injection material, etc. It can mean a material contained in an organic electroluminescent device before (for example, before vapor deposition) or a material contained in an organic electroluminescent device after (for example, after vapor deposition).

[0034] The organic electroluminescent compound represented by Formula I will be described in more detail below:

[0035] ;

[0036] In Formula I, R1 to R 32 Each is independently selected from hydrogen, deuterium, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

[0037] The inventors found that when the compound contains both a carbazole group and a 1,3,5-triazine structure substituted with a dibenzofuran group, and the nitrogen atom of the carbazole group is connected to the carbon atom of the triazine group through the ortho position of the biphenyl group, the device life can be significantly improved. This may be attributed to the fact that this specific group connection method forms a planar structure that is conducive to improving the device life.

[0038] Furthermore, the inventors have found that when R1 to R 32 When all of R1 to R 32 When the specific substituent in is deuterium, that is, when the specific positions of the main structure of Formula I are deuterated, the service life of the device can be further improved, and unexpectedly, the life effect of full deuteration can be achieved by deuterating the specific positions, thereby greatly reducing the deuteration cost. Of course, positions other than the specific positions can also be partially or fully deuterated. In this application, the specific positions refer to R1 to R4, R7 to R 11 , R 13 To R 17 Therefore, the present application expresses Formula I through the following Formula I-1 or Formula I-2:

[0039] ;

[0040] In Formula I-1, R5, R6, R 12 , R 18 To R 32 are as defined above, specifically, are each independently selected from hydrogen, deuterium, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

[0041] In some preferred embodiments, in order to make the compound structure simpler and easier to synthesize, in Formula I-1, R5, R6, R 12 , R 18 To R 32 are independently selected from hydrogen or deuterium. More preferably, R5, R6, R 12 , R 18 To R 32 All are hydrogen, or all or partly are deuterium.

[0042] In some preferred embodiments, in Formula I-1, when R5, R6, R 12 , R 18 To R 32 When all or part of the deuterium is deuterated, the average deuteration rate of the deuterated hydrogen in the formula I-1 is greater than 30%, so as to further improve the device efficiency. In the present application, the deuterated hydrogen refers to hydrogen that can be replaced by deuterium. The average deuteration rate of the deuterated hydrogen refers to the average value of the deuteration rate of the deuterated hydrogen. When the compound shown in formula I-1 is deuterated, each deuterated hydrogen may be deuterated or not, so the deuteration rate of each deuterated hydrogen can be calculated, and the deuteration rate can represent the degree of deuteration. Since there are a large number of deuterated hydrogens, each deuterated hydrogen corresponds to a deuteration rate. Theoretically, the deuteration rate of any deuterated hydrogen can be obtained by the following method: di %=N Di / N T ×100%,D di % represents the deuteration rate of deuterated hydrogen at the i-th site, N Di is the number of deuterated species in which the deuterated hydrogen at the i-th site is replaced by deuterium, N T is the total number of such compounds. When quantitative analysis is actually performed, the average deuteration rate of deuterated hydrogen can be calculated by hydrogen nuclear magnetic resonance testing: a standard sample (such as mesitylene trimethoxybenzene, 1,4-dioxane, etc.) is prepared and dissolved and diluted in a suitable deuterated reagent (such as deuterated DMSO, deuterated chloroform, etc.) to obtain a standard sample solution, and the test sample is dissolved in the standard sample solution for hydrogen nuclear magnetic resonance testing. The molar mass of the standard sample and the test sample is calculated, and then the average degree of deuteration is calculated in combination with hydrogen nuclear magnetic resonance spectrum analysis.

[0043] The present application provides an organic electroluminescent material, including the aforementioned organic electroluminescent compound. The organic electroluminescent compound can be used alone or in combination with other conventional materials. In some embodiments, the organic electroluminescent compound is used as a luminescent host material and in combination with a conventional luminescent guest material.

[0044] In some preferred embodiments, the organic electroluminescent material further comprises a carbazole derivative, which may be any known carbazole compound. The carbazole derivative is used as a p-type light-emitting host material (pGH), and the organic electroluminescent compound is used as an n-type light-emitting host material (nGH). The two are matched with each other to further improve the service life of the device.

[0045] In some preferred embodiments, the structural formula of the carbazole derivative is shown in Formula II or Formula III below:

[0046] ;

[0047] In Formula II and Formula III, R 33 and R 34 Each independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted furyl; the substitutable positions in the formula II and the formula III may be singly substituted or polysubstituted, and the substituents are independently associated with the aforementioned R1 to R 32 The positions that can be substituted in Formula II and Formula III can be on the main structure or on R 33 and R 34 superior.

[0048] In some embodiments, for ease of synthesis, R 33 and R 34 same.

[0049] In some preferred embodiments, the structural formula of the carbazole derivative is as shown in Formula II, wherein R 33 and R 34 All are biphenyl groups, and the substitutable positions in Formula II may be partially or fully deuterated.

[0050] In some preferred embodiments, the mass ratio of the organic electroluminescent compound to the carbazole derivative is 8:2 to 2:8, preferably 3:7 to 4:6.

[0051] The synthesis of the organic electroluminescent compound represented by Formula I of the present application can be carried out using known methods. For example, a cross-coupling reaction using transition metals such as nickel and palladium, or a CC, CN coupling reaction using transition metals such as magnesium or zinc can be used. Suzuki reaction and Buchwald reaction are preferred. The compounds represented by Formula II and Formula III of the present application are known and can be prepared by synthetic methods known in the art.

[0052] The present application also provides an organic electroluminescent device, which may include an anode, a cathode, and at least one organic layer between the anode and the cathode. The organic layer may contain the aforementioned organic electroluminescent compound or the aforementioned organic electroluminescent material. The organic electroluminescent compound or the aforementioned organic electroluminescent material may be contained in any one layer selected from the following: a light-emitting layer, a hole injection layer, a hole transport layer, a hole auxiliary layer, a light-emitting auxiliary layer, an electron transport layer, an electron buffer layer, an electron injection layer, an intermediate layer, a hole blocking layer, and an electron blocking layer. In some embodiments, the organic electroluminescent device may include an anode, a cathode, and at least one light-emitting layer between the anode and the cathode, wherein the light-emitting layer may contain the aforementioned organic electroluminescent compound or the aforementioned organic electroluminescent material.

[0053] As an example, the structure of the organic electroluminescent device may be one of the following:

[0054] (1) An organic electroluminescent device comprises 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, i.e., anode / hole injection layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode.

[0055] (2) Anode / hole injection layer / second hole transport layer / first hole transport layer / light-emitting layer / first electron transport layer / cathode.

[0056] (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.

[0057] (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.

[0058] (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.

[0059] (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.

[0060] (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.

[0061] (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.

[0062] (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.

[0063] (10) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / electron transport layer / electron injection layer / cathode.

[0064] (11) Anode / hole injection layer / first hole transport layer / second hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode.

[0065] (12) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / electron transport layer / cathode.

[0066] (13) Anode / hole injection layer / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / cathode.

[0067] (14) Anode / hole injection layer / hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode.

[0068] (15) Anode / hole injection layer / first hole transport layer / second hole transport layer / light-emitting layer / hole blocking layer / electron transport layer / cathode.

[0069] The light emission direction of the organic electroluminescent device can be emitted from the anode side or the cathode side. When emitted from the cathode side, the difference from structures (1) to (15) is that a covering layer needs to be added on the cathode side.

[0070] Some specific functional layers in the organic electroluminescent device are described below.

[0071] Substrate:

[0072] The substrate is generally located below the anode, and the substrate may be made of plastic or glass, and may be rigid or bendable. The substrate is provided with a driving unit, which may drive the corresponding pixel to emit light.

[0073] anode:

[0074] Usually, the anode has requirements such as good conductivity, smooth surface, and no cracks. At the same time, there are certain requirements for the work function, mainly to match the hole injection layer and exert the hole injection effect. When the top emission method (cathode side light emission) is adopted, the anode adopts 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~200nm. A reflective electrode is set under the anode (close to 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 and other metals. The reflectivity of the reflective electrode is relatively high, and the reflectivity is required to be more than 90%. The thickness is usually used at a thickness of 100nm~500nm, preferably in the range of 80nm~150nm. When the bottom emission method (light emitting from the substrate side) is adopted, the anode adopts a metal compound with a work function of 4.2eV or more, for example, indium tin oxide alloy, tin oxide, indium zinc oxide, gold, silver, platinum, copper, carbon nanotubes, carbon nanowires, graphene, etc. The thickness is 10nm~1μm, preferably 50nm~200nm. The anode can be made by forming a thin film of the electrode material by evaporation, sputtering, coating, etc.

[0075] Hole injection layer:

[0076] The thickness of the hole injection layer may be 100 angstroms to 300 angstroms. Preferably, the hole injection layer comprises a hole injection host material and a hole dopant, wherein the mass proportion of the hole dopant may be 1% to 5%. The hole injection host material is selected from the following group:

[0077] ;

[0078] Wherein: L1~L4, when present, are independently selected from a single bond or a phenylene group; Ar1~Ar 10 When each exists, it is independently selected from a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms, and when substituted, the substituent is selected from an alkyl group having 1 to 10 carbon atoms; preferably, Ar1 to Ar2 10 When each is present, it is independently selected from phenyl, biphenyl, dimethylfluorenyl, dibenzofuranyl, dibenzothiophenyl, N-phenylcarbazolyl, benzo[B]naphtho[2,3-D]furan, benzo[B]naphtho[1,2-D]furan, benzo[B]naphtho[2,1-D]furan; R 35 and R 36When present, it is independently selected from substituted or unsubstituted alkyl having 1 to 10 carbon atoms, substituted or unsubstituted aryl having 6 to 30 carbon atoms, substituted or unsubstituted heteroaryl having 3 to 30 carbon atoms, and when substituted, the substituent is selected from alkyl having 1 to 10 carbon atoms, or R 35 and R 36 The bonds form a ring.

[0079] In some preferred embodiments, the hole dopant is selected from the following compounds:

[0080] ; Among them, R 37 ~R 51 Each is independently selected from fluorine, trifluoromethyl, cyano, and nitro. 52 ~R 53 Each is independently selected from substituted or unsubstituted aryl, and the substituent may be selected from fluorine, trifluoromethyl, cyano, nitro.

[0081] In some specific embodiments, the hole dopant is selected from the following compounds:

[0082] .

[0083] First hole transport layer: The material selection range of the first hole transport layer is the same as that of the hole injection host material.

[0084] In some preferred embodiments, the material of the first hole transport layer is selected from the following group:

[0085] .

[0086] The thickness of the first hole transport layer may be 3nm-150nm. When there is no second hole transport layer, the thickness of the first hole transport layer is 40nm-150nm; when there is a second hole transport layer, the thickness of the first hole transport layer is 3nm-40nm.

[0087] Second hole transport layer:

[0088] The thickness of the second hole transport layer may be 5 nm to 150 nm. The material of the second hole transport layer is selected from the following group:

[0089] ;

[0090] Among them, R 54 , R 55 and R 56When each is present, it is independently selected from hydrogen, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 30 carbon atoms.

[0091] In some preferred embodiments, the material of the second hole transport layer is selected from the following compounds:

[0092] .

[0093] Electron blocking layer:

[0094] The electron blocking layer can have both hole transport function and electron blocking function. At the same time, the higher triplet excitation energy level of the electron blocking layer can block the excitons generated in the light-emitting layer in the light-emitting layer, thereby improving the luminous efficiency of the device. The electron blocking layer can be formed of conventional materials.

[0095] Luminous layer:

[0096] The light-emitting layer generally includes a light-emitting host material and a light-emitting guest material. In some preferred embodiments, the light-emitting host material includes the aforementioned organic electroluminescent compound or the aforementioned organic electroluminescent material. The light-emitting guest material can be any known conventional material, for example, it can be a metallized complex compound selected from iridium (Ir), osmium (Os), copper (Cu) and platinum (Pt), and in some cases, it can be preferably an ortho-metallized complex compound selected from iridium (Ir), osmium (Os), copper (Cu) and platinum (Pt), and in some cases, it can be more preferably an ortho-metallized iridium complex compound.

[0097] The light-emitting layer is a layer from which light is emitted, and may be a single layer or multiple layers. When the light-emitting layer comprises both the organic electroluminescent compound shown in Formula I and the carbazole derivative, the organic electroluminescent compound and the carbazole derivative may be contained in one layer, or may be contained in corresponding different light-emitting layers.

[0098] In some preferred embodiments, in the light-emitting layer, the mass percentage of the light-emitting host material is 95% to 99%, and the mass percentage of the light-emitting guest material is 1% to 5%.

[0099] Hole blocking layer:

[0100] The hole blocking layer can be used to enhance the balance of hole and electron concentrations. Inserting a hole blocking layer between the light-emitting layer and the electron transport layer can balance the carrier concentration and prevent exciton quenching. The hole blocking layer material can be a conventional material with strong stability, good film forming properties and a sufficiently high highest molecular occupied orbital.

[0101] Electron transport layer:

[0102] The electron transport layer may be a single layer or a multi-layer. As an example, the electron transport layer may include a first electron transport layer and / or a second electron transport layer.

[0103] The thickness of the first electron transport layer can be 3nm~40nm, 3nm~10nm, 10nm~20nm, 20nm~30nm, 30nm~40nm, 20nm~40nm, etc. The first electron transport layer can be a single compound or mixed with other metal compounds, such as 8-hydroxyquinoline lithium. In some embodiments, the material of the first electron transport layer is selected from s-triazine compounds. In some preferred embodiments, the material of the first electron transport layer is selected from the following compounds:

[0104] ; L 1-1 is selected from a single bond, phenyl, biphenyl, naphthyl; R 1-1 Selected from hydrogen, phenyl, biphenyl; Ar 1-1 ~Ar 3-1 Independently selected from hydrogen, phenyl, 9,9'-dimethylfluorenyl, 9,9'-diphenylfluorenyl, 9,9'-spirofluorenyl, 9,9'-xanthenespirofluorenyl, and phenanthryl.

[0105] Preferably, the material of the first electron transport layer is selected from the following group:

[0106] .

[0107] The thickness of the second electron transport layer may be 10 nm to 40 nm. The material of the second electron transport layer is selected from the following group:

[0108] ;

[0109] Wherein, L5 to L8, when present, are independently selected from a single bond, phenyl, biphenyl, naphthyl, 9,9'-dimethylfluorenyl, 9,9'-spirobifluorenyl; Ar 13 ~Ar 16 When each exists, it is independently selected from a substituted or unsubstituted C6-C50 aryl group, a substituted or unsubstituted C3-C50 heteroaryl group, and a substituted or unsubstituted phosphonyl group.

[0110] Preferably, the material of the second electron transport layer is selected from the following group:

[0111] .

[0112] In some preferred embodiments, the second electron transport layer further comprises a metal or a metal compound. For example, the metal compound is an alkali metal compound, an alkaline earth metal compound, a rare earth metal compound, etc. More specific examples include metal lithium compounds, metal calcium compounds, metal magnesium compounds, metal samarium compounds, metal ytterbium compounds, etc. More specific examples include 8-hydroxyquinoline lithium, lithium fluoride, magnesium fluoride, ytterbium fluoride, calcium fluoride, etc. When the second electron transport material is mixed with the metal compound, the mass proportion of the second electron transport material can be 20%~80%, 20%~40%, 40%~60%, 60%~80%, etc. When the second electron transport material is mixed with a metal, for example, with an alkali metal, an alkaline earth metal, a rare earth metal, and more specifically with lithium metal, magnesium metal, calcium metal, ytterbium metal, samarium metal, and the like, when mixed with a metal, the mass proportion of the second 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%, and the like.

[0113] Electron injection layer:

[0114] The material of the electron injection layer may be selected from alkali metals, alkaline earth metals, rare earth metals, or inorganic substances or coordination compounds thereof.

[0115] cathode:

[0116] The cathode needs to have a material with good electrical conductivity and good surface flatness. In order to improve the electron injection capability, a material with a small work function is usually selected. The cathode material can be a single-layer cathode, or a double-layer or multi-layer cathode, generally a metal or a metal alloy. For a single-layer cathode, silver, copper, aluminum, gold, or alloys of these metals with other metals, such as alloys with rare earth metals, alkali metals, and alkaline earth metals, can be used, which can be listed as magnesium-indium alloy, magnesium-aluminum alloy, aluminum-potassium alloy, aluminum-scandium-potassium alloy, magnesium-silver alloy, silver-ytterbium alloy, silver-samarium alloy, etc. If the cathode uses a double-layer metal, the cathode close to the light-emitting layer can use alkali metals, alkaline earth metals, rare earth metals, etc., such as lithium, calcium, magnesium, ytterbium, etc., to increase the electron injection ability. The cathode layer far from the light-emitting side is mainly used to improve the conductivity. Generally, silver, copper, aluminum, gold or alloys of these metals and other metals can be used, such as alloys with rare earth metals, alkali metals, and alkaline earth metals, which can be listed as magnesium-indium alloy, magnesium-aluminum alloy, aluminum-potassium alloy, aluminum-scandium-potassium alloy, magnesium-silver alloy, silver-ytterbium alloy, silver-samarium alloy, etc. The cathode can also be formed into a thin film by evaporation, sputtering, etc. When light comes out from the anode side, the cathode is required to be non-transparent, and a cathode larger than 100nm can be evaporated. When light comes out from the cathode side, the cathode is required to be transparent, and the transmittance at this time should be greater than 40%, and the thickness is 10nm~20nm.

[0117] Overlay:

[0118] When light comes out from the cathode side, photons resonate with electrons in the cathode metal to reduce the light extraction efficiency. Adding a covering layer on the side of the cathode away from the light-emitting layer can reduce this effect and effectively improve the light efficiency. When adding a covering layer, directly use a covering layer material with a high refractive index and a low absorption coefficient, for example, a material with a refractive index greater than 1.9 at a wavelength of 460nm and a material with an absorption rate less than 0.01%, preferably a material with a refractive index greater than 2.0 at a wavelength of 460nm and an absorption rate less than 0.01%, and more preferably a material with a refractive index greater than 2.1 at a wavelength of 460nm and an absorption rate less than 0.01%.

[0119] In some embodiments, the material of the cover layer is selected from the group consisting of:

[0120] .

[0121] Each layer of the organic electroluminescent device can be formed by a dry film-forming method, such as vacuum evaporation, sputtering, plasma, ion plating, etc., or a wet film-forming method, such as inkjet printing, nozzle printing, slit coating, spin coating, dip coating, flow coating, etc. When a wet film-forming method is used, a thin film can be formed by dissolving or diffusing the material forming each layer in any suitable solvent, such as ethanol, chloroform, tetrahydrofuran, dioxane, etc. There is no particular limitation on the solvent, as long as the material forming each layer is soluble or dispersible in the solvent, which does not cause any problem when forming the film.

[0122] In addition, the organic electroluminescent compound shown in the present application formula I and the carbazole derivative can be formed into films by the above listed method, usually by co-evaporation method or mixed evaporation method. Co-evaporation is a mixed deposition method in which two or more materials are placed in a corresponding single crucible source and an electric current is applied to two chambers simultaneously to evaporate the material. Mixed evaporation is a mixed deposition method in which two or more materials are mixed in a crucible source before being evaporated, and an electric current is applied to a chamber to evaporate the material. In addition, if the organic electroluminescent compound and the carbazole derivative are present in the same layer or different layers in the organic electroluminescent device, the two compounds can form a film individually. For example, the carbazole derivative can be deposited after the organic electroluminescent compound is deposited.

[0123] The preparation method and characteristics of the organic electroluminescent compound of the present application, as well as the characteristics of the organic electroluminescent material and organic electroluminescent device containing the same will be explained in detail below in combination with the representative compounds of the present application, so as to understand the technical solution of the present application, but the technical solution of the present application is not limited to the following examples.

[0124] The initial raw materials and solvents of the examples of the present application were purchased from Shanghai Titan Technology Co., Ltd., some commonly used OLED intermediates and other products were purchased from domestic OLED intermediate manufacturers; various palladium catalysts, ligands, etc. were purchased from Shaanxi Ruike New Materials Co., Ltd. 1 HNMR data were measured using a (400MHz) nuclear magnetic resonance instrument (manufactured by Bruker, Germany); HPLC data were measured using a Waters Corporation UPLC ultra-high performance liquid chromatograph. LC-MS (liquid chromatography-mass spectrometry) was tested on a UPLC+SQD2 instrument from Waters Corporation. The experimental methods for which specific conditions are not specified in the following examples are usually measured in accordance with national standards. If there are no corresponding national standards, then the general international standards, conventional methods and conditions, or the conditions recommended by the manufacturer, or the product specifications are selected. Unless otherwise specified, all percentages are weight percentages.

[0125] Compound

[0126] Example 1

[0127] This embodiment provides a method for preparing compound 1, comprising the following steps:

[0128] (1) Preparation of 3-chloro-2-fluoro-1,1'-biphenyl-2',3',4',5',6'-d5

[0129]

[0130] A mixed solvent of toluene (800 mL), ethanol (200 mL) and water (200 mL) was added to a 3L three-necked flask, and 3-chloro-2-fluorobromobenzene (100 g, 477 mmol, 1.00 eq), deuterated benzene boronic acid (63.7 g, 501 mmol, 1.05 eq), potassium carbonate (79.2 g, 573 mmol, 1.20 eq) and tetrakis(triphenylphosphine)palladium (2.76 g, 2.39 mmol, 0.005 eq) were added in sequence with stirring. Heating was started under nitrogen protection, and the reaction was refluxed for 4 hours. Stop heating and stirring, cool to room temperature, separate the lower aqueous phase, concentrate the organic phase to obtain a brown oil, and purify it by silica gel column chromatography to obtain 3-chloro-2-fluoro-1,1'-biphenyl-2',3',4',5',6'-d5 (colorless oil, 97.0 g, 458 mmol, yield 96%).

[0131] (2) Preparation of 2-(2-fluoro-[1,1'-biphenyl]-3-yl-2',3',4',5',6'-d5)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

[0132]

[0133] Add 1 L of toluene to a 3 L three-necked flask, and add 3-chloro-2-fluoro-1,1'-biphenyl (97.0 g, 458 mmol, 1.00 eq), bispinacol diboron (151 g, 596 mmol, 1.30 eq), potassium acetate (90.0 g, 917 mmol, 2.00 eq), Pd2dba3 (4.20 g, 4.58 mmol, 0.01 eq) and X-Phos (4.37 g, 9.16 mmol, 0.02 eq) in sequence under stirring, start heating under nitrogen protection, and reflux for 5 hours. The mixture was cooled to room temperature, 1 L of water was added to the system and stirred for 5 min. The mixture was separated, the organic phase was retained, and a black oil was obtained after concentration. The oil was purified by silica gel column chromatography (mobile phase: toluene) to obtain 2-(2-fluoro-[1,1'-biphenyl]-3-yl-2',3',4',5',6'-d5)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (light yellow solid, 101 g, 334 mmol, yield 73%).

[0134] (3) Preparation of 2-(dibenzo[B,D]furan-3-yl)-4-(2-fluoro-[1,1'-biphenyl]-3-yl-2',3',4',5',6'-d5)-6-phenyl-1,3,5-triazine

[0135]

[0136] To a 2L three-necked flask, add 500mL of tetrahydrofuran, and add 2-chloro-4-(dibenzo[B,D]furan-3-yl)-6-phenyl-1,3,5-triazine (50.0g, 140mmol, 1.00eq), 2-(2-fluoro-[1,1'-biphenyl]-3-yl-2',3',4',5',6'-d5)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (44.5g, 147mmol, 1.05eq), SPhos (0.57g, 1.40mmol, 0.01eq), and Pd(PPh3)4 (0.81g, 0.70mmol, 0.005eq) in sequence under stirring. Turn on heating under nitrogen protection, reflux for 4 hours, and add an aqueous solution of potassium carbonate (140mL, 2M) dropwise to the system. After completion, the reflux reaction was continued for 1 hour. The mixture was allowed to stand, cooled to room temperature, the lower aqueous phase was separated, anhydrous ethanol (500 mL) was added, and the mixture was stirred for crystallization at room temperature for 2 hours, filtered, and the filter cake was collected and purified by silica gel column chromatography (mobile phase: toluene) to obtain 2-(dibenzo[B,D]furan-3-yl)-4-(2-fluoro-[1,1'-biphenyl]-3-yl-2',3',4',5',6'-d5)-6-phenyl-1,3,5-triazine (white powder, 62.0 g, 124 mmol, yield 89.0%).

[0137] (4) 2'-nitro-1,1':4',1''-terphenyl-2,2'',3,3'',4,4'',5,5'',6,6''-d 10 Preparation

[0138]

[0139] 800 mL of toluene, 200 mL of anhydrous ethanol, and 200 mL of deionized water were added to a 2L three-necked flask, and 1,4-dibromo-2-nitrobenzene (100 g, 356 mmol, 1.00 eq), deuterated phenylboronic acid (94.9 g, 748 mmol, 2.10 eq), and sodium bicarbonate (126 g, 1.50 mol, 4.20 eq) were added in sequence under stirring. The mixture was heated under nitrogen protection and refluxed for 2.5 hours. The mixture was cooled to room temperature, allowed to stand for separation, and the lower aqueous phase was removed. The organic phase was concentrated and purified by silica gel column chromatography to obtain 2'-nitro-1,1':4',1''-terphenyl-2,2'',3,3'',4,4'',5,5'',6,6''-d 10 (white powder, 88.0 g, 308 mmol, yield 88.6%)

[0140] (5) Preparation of 2-(phenyl-d5)-9H-carbazole-5,6,7,8-d4

[0141]

[0142] Triethyl phosphite (530 mL) was added to a 1 L three-necked flask, and 2'-nitro-1,1':4',1''-terphenyl-2,2'',3,3'',4,4'',5,5'',6,6''-d was added under stirring. 10 (88.0 g, 308 mmol), heating was started under nitrogen protection, and reflux reaction was carried out for 6 hours. Cooled to room temperature, 1 L of methanol was added dropwise to the three-necked flask for crystallization, and stirring was continued for 2 hours at room temperature, and filtered to obtain 2-(phenyl-d5)-9H-carbazole-5,6,7,8-d4 (light yellow powder, 51.2 g, 308 mmol, yield 65.8%).

[0143] (6) Preparation of Compound 1

[0144]

[0145] Add 600 mL of DMF to a 2L three-necked flask, and add 2-(dibenzo[B,D]furan-3-yl)-4-(2-fluoro-[1,1'-biphenyl]-3-yl-2',3',4',5',6'-d5)-6-phenyl-1,3,5-triazine (62.0 g, 124 mmol, 1.00 eq), 2-(phenyl-d5)-9H-carbazole-5,6,7,8-d4 (31.4 g, 124 mmol) and cesium carbonate (60.8 g, 187 mmol, 1.50 eq) in sequence under stirring. Start heating under nitrogen protection and reflux for 6 hours. The mixture was cooled to room temperature, 1000 mL of toluene was added for dilution, 2000 mL of deionized water was added for washing, the aqueous phase was separated, and the organic phase was concentrated to obtain a brown-yellow solid, which was purified by silica gel column chromatography (mobile phase: toluene) to obtain compound 1 (9-(3-(4-(dibenzo[B,D]furan-3-yl)-6-phenyl-1,3,5-triazine-2-yl)-[1,1'-biphenyl]-2-yl-2',3',4',5',6'-d5)-2-(phenyl-d5)-9H-carbazole-5,6,7,8-d4) (72.0 g, 98.5 mmol, yield 79.2%).

[0146] Using LC-MS equipment equipped with APCI and ESI ion sources, the sample was directly injected into the MASS equipment for detection without passing through LC. Figure 1 The mass spectrum shown, Ms+1=731.69. Figure 2 This is the chromatogram of compound 1, HPLC: RT=29.410min, 99.9457%. Figure 3 is the H NMR spectrum of compound 1.

[0147] Example 2

[0148] This embodiment provides a method for preparing compound 2, comprising the following steps:

[0149] (1) Preparation of 3-chloro-2-fluoro-1,1'-biphenyl

[0150]

[0151] A mixed solvent of toluene (800 mL), ethanol (200 mL) and water (200 mL) was added to a 3L three-necked flask, and 3-chloro-2-fluorobromobenzene (100 g, 477 mmol, 1.00 eq), phenylboric acid (61.1 g, 501 mmol, 1.05 eq), potassium carbonate (79.2 g, 573 mmol, 1.20 eq) and tetrakis(triphenylphosphine)palladium (2.76 g, 2.39 mmol, 0.005 eq) were added in sequence under stirring, and heating was started under nitrogen protection, and reflux reaction was carried out for 4 hours. Heating and stirring were stopped, and the mixture was cooled to room temperature, and the lower aqueous phase was separated. The organic phase was concentrated to obtain a brown oil, which was purified by silica gel column chromatography (the mobile phase was n-hexane) to obtain 3-chloro-2-fluoro-1,1'-biphenyl (94.0 g, 455 mmol, yield 95.3%).

[0152] (2) Preparation of 2-(2-fluoro-[1,1'-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

[0153]

[0154] Add 1 L of toluene to a 3 L three-necked flask, and add 3-chloro-2-fluoro-1,1'-biphenyl (94.0 g, 455 mmol, 1.00 eq), bispinacol diboron (150 g, 591 mmol, 1.30 eq), potassium acetate (89.3 g, 910 mmol, 2.00 eq), Pd2dba3 (4.17 g, 4.55 mmol, 0.01 eq) and X-Phos (4.34 g, 9.10 mmol, 0.02 eq) in sequence under stirring, start heating under nitrogen protection, and reflux for 5 hours. The mixture was cooled to room temperature, 1 L of water was added to the system and stirred for 5 min. The mixture was separated, the organic phase was retained, and a black oil was obtained after concentration. The oil was purified by silica gel column chromatography (mobile phase: toluene) to obtain 2-(2-fluoro-[1,1'-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (94.9 g, 318 mmol, yield 70%).

[0155] (3) 2-(Dibenzo[B,D]furan-3-yl)-4-(2-fluoro-[1,1'-biphenyl]-3-yl)-6-phenyl-1,3,5-triazine

[0156]

[0157] Add 500 mL of tetrahydrofuran to a 2L three-necked flask, and add 2-chloro-4-(dibenzo[B,D]furan-3-yl)-6-phenyl-1,3,5-triazine (50.0 g, 140 mmol, 1.00 eq), 2-(2-fluoro-[1,1'-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolan (43.8 g, 147 mmol, 1.05 eq), SPho (0.57 g, 1.40 mmol, 0.01 eq), Pd(PPh3)4 (0.81 g, 0.70 mmol, 0.005 eq) in sequence under stirring, turn on heating under nitrogen protection, reflux reaction for 4 hours, and add potassium carbonate aqueous solution (140 mL, 2 M) dropwise to the system. After completion, continue reflux reaction for 1 hour. The mixture was allowed to stand and cooled to room temperature. The lower aqueous phase was separated and anhydrous ethanol (500 mL) was added to crystallize for 2 h. The mixture was filtered and the filter cake was collected and purified by silica gel column chromatography (mobile phase: toluene) to obtain 2-(dibenzo[B,D]furan-3-yl)-4-(2-fluoro-[1,1'-biphenyl]-3-yl)-6-phenyl-1,3,5-triazine (59.7 g, 121 mmol, yield 86.6%).

[0158] (4) Preparation of Compound 2

[0159]

[0160] 600 mL of DMF was added to a 2L three-necked flask, and 2-(dibenzo[B,D]furan-3-yl)-4-(2-fluoro-[1,1'-biphenyl]-3-yl)-6-phenyl-1,3,5-triazine (59.7 g, 121 mmol, 1.00 eq), 2-phenyl-9H-carbazole (29.4 g, 121 mmol) and cesium carbonate (59.1 g, 181 mmol, 1.50 eq) were added in sequence under stirring. The mixture was heated under nitrogen protection and refluxed for 6 hours. The mixture was cooled to room temperature, 1000 mL of toluene was added for dilution, 2000 mL of deionized water was added for washing, the aqueous phase was separated, and the organic phase was concentrated to obtain a brown-yellow solid, which was purified by silica gel column chromatography (mobile phase: toluene) to obtain 9-(3-(4-(dibenzo[B,D]furan-3-yl)-6-phenyl-1,3,5-triazine-2-yl)-[1,1'-biphenyl]-2-yl)-2-phenyl-9H-carbazole (72.0 g, 98.5 mmol, yield 79.2%).

[0161] Figure 4 This is the measured mass spectrum, MS: Ms+1=717.51. Figure 5 This is the chromatogram of compound 2, HPLC: RT=31.391min, 99.8788%. Figure 6is the H NMR spectrum of compound 2.

[0162] Example 3

[0163] This embodiment provides a method for preparing a fully deuterated compound 3, comprising the following steps:

[0164]

[0165] 9-(3-(4-(dibenzo[B,D]furan-3-yl)-6-phenyl-1,3,5-triazine-2-yl)-[1,1'-biphenyl]-2-yl)-2-phenyl-9H-carbazole (15.0 g, 20.9 mmol), 150 mL D2O, dry palladium carbon (3.00 g) were added to a 250 mL reactor. After nitrogen replacement three times, hydrogen replacement three times, the hydrogen pressure was maintained at 1 MPa, and the reaction was heated to 190 ° C for 6 days (144 hours). Cool to room temperature, filter, collect the filter cake and purify it by silica gel column chromatography to obtain 9-(3-(4-(dibenzo[B,D]furan-3-yl)-6-phenyl-1,3,5-triazine-2-yl)-[1,1'-biphenyl]-2-yl)-2-phenyl-9H-carbazole_d 32 (11.0 g, 14.7 mmol, yield 70.2%).

[0166] Figure 7 This is the measured mass spectrum, MS: Ms+1=739.74. Figure 8 This is the chromatogram of compound 3, HPLC: RT=29.967min, 99.5865%. Fig. 9 is the H NMR spectrum of compound 3.

[0167] Organic electroluminescent devices

[0168] The compounds of the present application used in the device examples are all purified by sublimation, and the purity is greater than 99.98%. The following examples are described by taking the compounds of the present application as the main material of the light-emitting layer of the green light OLED device as an example.

[0169] Example 4

[0170] refer to Fig.10 This embodiment provides a method for preparing an organic electroluminescent device, comprising the following steps:

[0171] On a glass substrate 101, a transparent ITO film layer (thickness 150 nm) is formed by magnetron sputtering to obtain an anode 102;

[0172] A mixed material of compound M1 and compound M2 is evaporated on the surface of the anode 102 as a hole injection layer 103, with a mixing ratio of 3:97 (mass ratio) and a thickness of 10 nm;

[0173] Subsequently, compound M2 (thickness 100 nm) and compound M3 (thickness 40 nm) are sequentially deposited on the surface of the hole injection layer 103 to obtain a hole transport layer 104 and an electron blocking layer 105 respectively;

[0174] Next, on the surface of the electron blocking layer 105 , the compound 1 (nGH), the compound M4 (pGH) and the compound M5 (GD) of the present application were co-evaporated at a mass ratio of 45:45:10 to form a light-emitting layer 106 (thickness 40 nm);

[0175] Subsequently, compound M6 is sequentially evaporated on the surface of the organic light-emitting layer 106 to form a hole blocking layer 107 (thickness 10 nm), and compound M7 and LiQ with a mixing ratio of 4:6 (mass ratio) are used to form an electron transport layer 108 (thickness 30 nm);

[0176] Finally, magnesium (Mg) and silver (Ag) are mixed and deposited on the surface of the electron transport layer 108 at an evaporation rate of 1:9 to form a cathode 109 with a thickness of 10 nm, thereby completing the preparation of the organic electroluminescent device.

[0177] The structural formulas of the compounds involved in the above preparation process are shown in Table 1 below.

[0178] Table 1 Structural formula of compounds

[0179]

[0180] Example 5

[0181] Compared with Example 4, the only difference in the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106 , Compound 2 is used instead of Compound 1.

[0182] Example 6

[0183] Compared with Example 4, the only difference in the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106 , Compound 3 is used instead of Compound 1.

[0184] Example 7

[0185] Compared with Example 4, the difference of the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106, the following compound pGH1 is used instead of compound M4:

[0186] .

[0187] Example 8

[0188] Compared with Example 4, the difference of the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106, the following fully deuterated compound pGH2 is used instead of compound M4:

[0189] .

[0190] Comparative Example 1

[0191] Compared with Example 4, the difference of the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106, the following compound C1 is used instead of compound 1:

[0192] .

[0193] Comparative Example 2

[0194] Compared with Example 4, the only difference in the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106, the following compound C2 is used instead of compound 1:

[0195] .

[0196] Comparative Example 3

[0197] Compared with Example 4, the only difference of the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106, the following compound C3 is used instead of compound 1:

[0198] .

[0199] Comparative Example 4

[0200] Compared with Example 4, the only difference in the method for preparing the organic electroluminescent device of this embodiment is that when forming the light-emitting layer 106, the following compound C4 is used instead of compound 1:

[0201] .

[0202] Device performance test

[0203] Each set of examples and comparative examples were produced and tested in the same batch. The LT95 life of the device was tested under dark conditions using a Foster life measurement system equipped with a power supply and a photodiode as a detection unit (test conditions: constant current 20 mA / cm 2 LT95 refers to the time required for the brightness to decrease from the initial brightness to 95%. Taking the device life of Comparative Example 1 as 100%, the life test results shown in Table 2 are obtained.

[0204] Table 2 Life test results

[0205]

[0206] According to the life comparison results of Example 5 and Comparative Examples 1 to 4, it can be seen that the structural formula of the compound of the present application contains both a carbazole group and a 1,3,5-triazine structure substituted by a dibenzofuran group, and the 1,3,5-triazine structure and the carbazole group are connected by the ortho position of the biphenyl group, which can significantly improve the device life.

[0207] Furthermore, according to the life comparison results of Examples 4 to 6, when the hydrogen at a specific position in the structural formula of the compound of the present application is deuterated, the service life of the device can be further improved. In particular, the present application can achieve the life effect of full deuteration only by deuterating a specific position.

[0208] Furthermore, according to the lifespan comparison results of Example 4 and Examples 7-8, it can be seen that when the carbazole derivative represented by Formula II of the present application is used as the p-type light-emitting host material, the device lifespan can be further improved.

[0209] The operating voltage and current efficiency of the organic electroluminescent devices of the above embodiments and comparative examples were calculated using a computer-controlled Keithley 2400 test system (the test current was 20 mA / cm 2 ), wherein the lower the operating voltage, the lower the power consumption. Taking the operating voltage and current efficiency of the device of Comparative Example 1 as 100%, the operating voltage and current efficiency test results shown in Table 3 are obtained.

[0210] Table 3 Working voltage and current efficiency test results

[0211]

[0212] Usually, the device life is in a trade-off relationship with voltage and efficiency. Therefore, when the device life is significantly improved, it may be at the expense of a larger part of the voltage and efficiency. According to the test results in Table 3, the compounds of the present application will not cause excessive sacrifice of voltage and efficiency. Therefore, the compounds of the present application can significantly improve the life while maintaining the voltage and efficiency at a good level. In particular, when the carbazole derivative shown in Formula II of the present application is used as a p-type light-emitting main material, while significantly improving the device life, it can also reduce the operating voltage and improve the device efficiency.

[0213] It should be noted that Example 4 uses a deuterated compound at a specific position of the present application, and Example 6 uses a fully deuterated compound of the present application. In theory, the lifespan improvement effect of Example 6 is significantly higher than that of the present embodiment, but the actual test results show that the lifespan of Example 4 is the same as that of Example 6, and the voltage and efficiency of the two are not much different. Therefore, when the deuterated compound at a specific position of the present application is applied to an organic electroluminescent device, an unexpected improvement effect is achieved, and the deuterated cost can also be greatly reduced.

[0214] The above description of the embodiments is to facilitate those of ordinary skill in the art to understand and apply the present application. It is obvious that those familiar with the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to pay creative labor. Therefore, the present application is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art based on the contents disclosed in the present application without departing from the scope and spirit of the present application are within the scope of the present application.

Claims

1. An organic electroluminescent compound, characterized in that: Its structural formula is shown in the following formula I-1: ； In Formula I-1, R5, R6, R 12 , R 18 To R 32 All are hydrogen.

2. An organic electroluminescent material, characterized in that: The organic electroluminescent compound according to claim 1 is included.

3. The organic electroluminescent material according to claim 2, characterized in that: The organic electroluminescent material also includes a carbazole derivative.

4. The organic electroluminescent material according to claim 3, characterized in that: The structural formula of the carbazole derivative is shown in the following formula II or formula III: 、 ； In Formula II and Formula III, R 33 and R 34 Each is independently selected from substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted furyl; The substitutable positions in Formula II and Formula III may be singly or polysubstituted, and each substituent is independently selected from hydrogen, deuterium, an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms.

5. The organic electroluminescent material according to claim 4, characterized in that: The structural formula of the carbazole derivative is shown in Formula II, wherein R 33 and R 34 All are biphenyl groups, and the substitutable positions in Formula II may be partially or fully deuterated.

6. The organic electroluminescent material according to any one of claims 3 to 5, characterized in that: The mass ratio of the organic electroluminescent compound to the carbazole derivative is 8:2 to 2:

8.

7. An organic electroluminescent device, characterized in that: The invention comprises the organic electroluminescent compound according to claim 1 or the organic electroluminescent material according to any one of claims 2 to 6.

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