Electron-blocking material, organic electroluminescent device, and method of preparation

Abstract

This application discloses an electron blocking material, an organic electroluminescent device, and a preparation method thereof, belonging to the field of display technology. The general formula of the electron blocking material is: at least one of groups A, B, and C is a group M, and the general formula of group M is: X is selected from C or Si; R is selected from C1-39 alkyl, C1-39 cycloalkyl, C2-39 alkenyl, C2-39 alkynyl, C6-39 aryl, C5-60 heteroaryl, C6-60 aryloxy, C1-39 alkoxy, C6-39 arylamino, C3-39 cycloalkyl, C3-39 heterocycloalkyl, C1-39 alkylsilyl, C1-39 alkylboryl, C6-39 arylboryl, C6-39 arylphosphinyl, C6-39 arylsilyl; L1 is a single bond, a C6-C15 arylene, or a C5-C15 heteroarylene; Ar1 ​​is either a group as indicated by group R, or hydrogen or deuterium. This can improve device efficiency and lifespan.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to electron blocking materials, organic electroluminescent devices, and their preparation methods. Background Technology

[0002] Organic electroluminescence displays (OLEDs) offer advantages such as being all-solid-state, having fast response times, and operating over a wide temperature range. An OLED consists of an anode, a cathode, and a light-emitting unit located between them. The light-emitting unit includes an organic light-emitting layer and hole transport regions and electron transport regions located on either side of it. Currently, an electron-blocking layer (EBL) is typically placed in the hole transport region. The electron-blocking layer controls the direction of electron flow and hinders reverse leakage current, thereby improving luminous efficiency.

[0003] However, the known electron blocking materials have limited effect on improving the performance of organic electroluminescent devices.

[0004] Public content

[0005] In view of this, the present disclosure provides electron blocking materials, organic electroluminescent devices and preparation methods, which can solve the technical problems existing in the related technologies.

[0006] Specifically, the following technical solutions are included:

[0007] On the one hand, an electron blocking material is provided, the general chemical formula of which is shown below:

[0008]

[0009] Wherein, at least one of group A, group B, and group C is group M, and those of group A, group B, and group C that are not group M are selected from aryl with 6-39 carbon atoms, heteroaryl with 5-60 carbon atoms, aryloxy with 6-60 carbon atoms, alkoxy with 1-39 carbon atoms, arylamino with 6-39 carbon atoms, cycloalkyl with 3-39 carbon atoms, heterocycloalkyl with 3-39 carbon atoms, alkylsilyl with 1-39 carbon atoms, alkylboryl with 1-39 carbon atoms, arylboryl with 6-39 carbon atoms, arylphosphinyl with 6-39 carbon atoms, or arylsilyl with 6-39 carbon atoms;

[0010] The general chemical formula of the group M is shown below:

[0011]

[0012] Where X is selected from C or Si;

[0013] R is independently selected from alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, aryloxy, alkoxy, arylamino, arylamino, heterocycloalkyl, alkylsilyl, alkylboronyl, arylboronyl, arylphosphinyl, or arylsilyl.

[0014] L1 is selected from single bonds, C6-C15 arylene groups, or C5-C15 heteroarylene groups;

[0015] Ar1 is selected from hydrogen, deuterium, alkyl with 1-39 carbon atoms, alkenyl with 2-39 carbon atoms, alkynyl with 2-39 carbon atoms, aryl with 6-39 carbon atoms, heteroaryl with 5-60 carbon atoms, aryloxy with 6-60 carbon atoms, alkoxy with 1-39 carbon atoms, arylamino with 6-39 carbon atoms, cycloalkyl with 3-39 carbon atoms, heterocycloalkyl with 3-39 carbon atoms, alkylsilyl with 1-39 carbon atoms, alkylboron with 1-39 carbon atoms, arylboron with 6-39 carbon atoms, arylphosphine with 6-39 carbon atoms, or arylsilyl with 6-39 carbon atoms.

[0016] In some possible implementations, at least some of the hydrogens in the R group can be deuterated; and / or,

[0017] Adjacent R groups can be linked together to form a ring.

[0018] In some possible implementations, one of the groups A, B, and C is group M.

[0019] In some possible implementations, the X in group M is selected from Si.

[0020] In some possible implementations, two of the groups A, B, and C are group M.

[0021] In some possible implementations, the X in one group M is selected from C, and the X in the other group M is selected from Si;

[0022] Alternatively, X in both groups M can be selected from C;

[0023] Alternatively, the X in both groups M can be selected from Si.

[0024] On the other hand, an organic electroluminescent device is provided, the organic electroluminescent device including an anode, a cathode and a light-emitting unit, the light-emitting unit being located between the anode and the cathode, and the light-emitting unit including an organic light-emitting layer and a hole transport region and an electron transport region located on both sides of the organic light-emitting layer;

[0025] The hole transport region includes a stacked hole transport layer and an electron blocking layer, wherein the electron blocking layer is prepared using any of the electron blocking materials described above.

[0026] In some possible implementations, the hole transport layer is prepared using a hole transport material, the general chemical formula of which is shown below:

[0027]

[0028] Ar2-Ar5 are each independently selected from aryl groups with 6-39 carbon atoms, heteroaryl groups with 5-60 carbon atoms, aryloxy groups with 6-60 carbon atoms, alkoxy groups with 1-39 carbon atoms, arylamino groups with 6-39 carbon atoms, and arylsilyl groups with 6-39 carbon atoms.

[0029] L2 is selected from single bonds, C6-C15 aryl groups, or C5-C15 heteroaryl groups.

[0030] In some possible implementations, the HOMO level of the hole transport layer is a, the HOMO level of the electron blocking layer is b, and the HOMO level of the organic light-emitting layer is c.

[0031] a, b, and c satisfy: |ab| < |bc|.

[0032] In some possible implementations, the organic light-emitting layer includes a host light-emitting material and a light-emitting layer dopant;

[0033] The hole mobility of the organic light-emitting layer is μh, and the electron mobility is μe. μh and μe satisfy μe / μh>2.

[0034] In another aspect, a method for preparing an electron blocking material is provided, wherein the electron blocking material is as described in any of the above descriptions;

[0035] The method for preparing the electron blocking material includes: performing a CN coupling reaction between an organohalide monomer corresponding to the M group and an amine monomer to obtain the electron blocking material.

[0036] In some possible implementations, the organohalide monomer corresponding to the M group is prepared by the following method: performing a CC coupling reaction between the organohalide submonomer and a halogen-containing borate monomer to obtain the organohalide monomer corresponding to the M group;

[0037] The halogen contained in the organohalide monomer corresponding to the M group comes from the halogen in the boric acid monomer.

[0038] The beneficial effects of the technical solutions provided in this disclosure include at least the following:

[0039] The electron blocking material provided in this disclosure, by defining its chemical structure as described above, such that at least one of the A, B, and C groups is a group M, has at least the following advantages: First, the aromatic amine structure of the electron blocking material is connected to the aryl group branched from the X position of the group M, which helps to increase the tortuosity of the electron blocking material, thereby increasing its stereochemistry and improving the T1 (triple-state energy level), thus improving the efficiency and lifetime of the organic electroluminescent device. Second, this type of electron blocking material has higher thermal stability, resulting in a longer lifetime. Third, the specific connection method of this type of electron blocking material places its HOMO energy level at a suitable level, reducing the interface gap (energy level difference), which is conducive to hole injection, allowing holes and electrons to recombine more efficiently, reducing charge accumulation, and reducing device capacitance. This helps the green photonics to exhibit better color display effects when working in conjunction with the blue and red photonics. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the structure of an exemplary electroluminescent device provided in an embodiment of this disclosure;

[0042] Figure 2 This is a schematic diagram of another exemplary electroluminescent device provided in an embodiment of this disclosure.

[0043] The reference numerals in the attached figures represent:

[0044] 100, Anode; 200, Cathode; 300, Organic light-emitting layer; 400, Hole transport region; 401, Hole transport layer; 402, Electron blocking layer; 403, Hole injection layer; 500, Electron transport region; 501, Electron transport layer; 502, Electron injection layer; 503, Hole blocking layer.

[0045] The accompanying drawings have illustrated specific embodiments of this disclosure, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this disclosure to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0046] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0047] In the embodiments of this disclosure, directional terms such as "up" and "down" are generally used in the following ways: Figure 1 and Figure 2 The relative positions shown are based on the given information, and these directional terms are used only to more clearly describe the relationships between structures, not to describe absolute positions. Positions may change when the product is placed in different orientations; for example, "up" and "down" may be interchanged.

[0048] On one hand, embodiments of this disclosure provide an electron blocking material, the general chemical formula of which is shown below:

[0049]

[0050] In this configuration, at least one of group A, group B, and group C is group M. Groups A, B, and C that are not group M are selected from aryl (6-39 carbon atoms), heteroaryl (5-60 carbon atoms), aryloxy (6-60 carbon atoms), alkoxy (1-39 carbon atoms), arylamino (6-39 carbon atoms), cycloalkyl (3-39 carbon atoms), heterocycloalkyl (3-39 carbon atoms), alkylsilyl (1-39 carbon atoms), alkylboronyl (1-39 carbon atoms), arylboronyl (6-39 carbon atoms), arylphosphine (6-39 carbon atoms), or arylsilyl (6-39 carbon atoms). All of the above groups may be substituted or unsubstituted.

[0051] The general chemical formula of group M is shown below:

[0052]

[0053] Where X is selected from C or Si.

[0054] Each of the R groups is independently selected from alkyl groups with 1-39 carbon atoms, cycloalkyl groups with 1-39 carbon atoms, alkenyl groups with 2-39 carbon atoms, alkynyl groups with 2-39 carbon atoms, aryl groups with 6-39 carbon atoms, heteroaryl groups with 5-60 carbon atoms, aryloxy groups with 6-60 carbon atoms, alkoxy groups with 1-39 carbon atoms, arylamino groups with 6-39 carbon atoms, cycloalkyl groups with 3-39 carbon atoms, heterocycloalkyl groups with 3-39 carbon atoms, alkylsilyl groups with 1-39 carbon atoms, alkylboryl groups with 1-39 carbon atoms, arylboryl groups with 6-39 carbon atoms, arylphosphinyl groups with 6-39 carbon atoms, or arylsilyl groups with 6-39 carbon atoms. Multiple R groups can be all the same, partially the same, or different from each other. Furthermore, the above groups can be substituted or unsubstituted.

[0055] L1 is selected from single bonds, C6-C15 aryl groups, or C5-C15 heteroaryl groups.

[0056] Ar1 is selected from hydrogen, deuterium, alkyl groups with 1-39 carbon atoms, alkenyl groups with 2-39 carbon atoms, alkynyl groups with 2-39 carbon atoms, aryl groups with 6-39 carbon atoms, heteroaryl groups with 5-60 carbon atoms, aryloxy groups with 6-60 carbon atoms, alkoxy groups with 1-39 carbon atoms, arylamino groups with 6-39 carbon atoms, cycloalkyl groups with 3-39 carbon atoms, heterocycloalkyl groups with 3-39 carbon atoms, alkylsilyl groups with 1-39 carbon atoms, alkylboronyl groups with 1-39 carbon atoms, arylboronyl groups with 6-39 carbon atoms, arylphosphinyl groups with 6-39 carbon atoms, or arylsilyl groups with 6-39 carbon atoms. All groups except hydrogen and deuterium can be substituted or unsubstituted.

[0057] The electron blocking material provided in this disclosure, by defining its chemical structure as described above, such that at least one of the A, B, and C groups is a group M, has at least the following advantages: First, the aromatic amine structure of the electron blocking material is connected to the aryl group branched from the X position of the group M, which helps to increase the tortuosity of the electron blocking material, thereby increasing its stereochemistry and improving the T1 (triple-state energy level), thus improving the efficiency and lifetime of the organic electroluminescent device. Second, this type of electron blocking material has higher thermal stability, resulting in a longer lifetime. Third, the specific connection method of this type of electron blocking material places its HOMO energy level at a suitable level, reducing the interface gap (energy level difference), which is conducive to hole injection, allowing holes and electrons to recombine more efficiently, reducing charge accumulation, and reducing device capacitance. This helps the green photonics to exhibit better color display effects when working in conjunction with the blue and red photonics.

[0058] The electron blocking material provided in this disclosure is advantageous for fabricating organic electroluminescent devices that emit green and red light. In particular, when fabricating organic electroluminescent devices that emit green light, they exhibit superior color display effects.

[0059] In some examples, at least some of the hydrogens in the R group can be deuterated (e.g., this includes partial or complete deuteration of hydrogens); and / or, adjacent R groups can be linked together to form a ring.

[0060] Since deuterium is an isotope of hydrogen, and its atomic mass is twice that of hydrogen, deuterium has a lower vibrational energy level. This results in shorter CD bonds with longer bond energies and smaller stretching vibrations compared to CH bonds. The deuterated R group replaces the relatively energy-consuming CH vibration with CD vibration, which reduces the energy loss of electron-blocking materials, thereby improving their efficiency and lifetime.

[0061] In some examples, one of the groups A, B, and C is group M. Furthermore, the X in this single group M can be selected from Si.

[0062] In other examples, two of the groups A, B, and C are group M. For example, groups A and B are group M, groups B and C are group M, and groups A and C are group M.

[0063] Furthermore, for these two groups M, the X in one group M is selected from C, and the X in the other group M is selected from Si; or, the X in both groups M is selected from C; or, the X in both groups M is selected from Si.

[0064] Based on the chemical structural formulas of the electron blocking materials provided in the embodiments of this disclosure, the following are examples of some specific electron blocking materials, some of which contain CD3 groups.

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[0201] On the other hand, embodiments of this disclosure also provide an organic electroluminescent device, as shown in the attached figure. Figure 1 As shown, the organic electroluminescent device includes an anode 100, a cathode 200, and a light-emitting unit. The light-emitting unit is located between the anode 100 and the cathode 200, and includes an organic light-emitting layer 300 and hole transport regions 400 and electron transport regions 500 located on both sides of the organic light-emitting layer 300. The hole transport region 400 includes a stacked hole transport layer 401 and an electron blocking layer 402, and the electron blocking layer 402 is prepared using any of the aforementioned electron blocking materials.

[0202] The organic electroluminescent device provided in this disclosure has all the advantages of the aforementioned electron blocking materials. The overall performance of this organic electroluminescent device is significantly improved, which is particularly beneficial for extending its lifespan, reducing operating voltage, and enhancing its color display effect.

[0203] In this embodiment of the disclosure, the electron blocking layer 402 can be a single layer or multiple layers (e.g., two layers). When the electron blocking layer 402 is multiple layers, the multiple electron blocking layers 402 are stacked sequentially.

[0204] For example, Figure 1 An example of an organic electroluminescent device is provided, wherein the electron blocking layer 402 is arranged in a single layer; Figure 2 Another organic electroluminescent device is illustrated, in which the electron blocking layer 402 is arranged in a double layer.

[0205] In some examples (1), the hole transport region 400 includes a hole transport layer 401 and an electron blocking layer 402, wherein the anode 100, the hole transport layer 401, the electron blocking layer 402, and the organic light-emitting layer 300 are stacked in sequence.

[0206] In some examples (2), the hole transport region 400 includes a hole transport layer 401, an electron blocking layer 402 and a hole injection layer 403, wherein the anode 100, the hole injection layer 403, the hole transport layer 401, the electron blocking layer 402 and the organic light-emitting layer 300 are stacked in sequence.

[0207] In some examples (3), the electron transport region 500 includes an electron transport layer 501, wherein the cathode 200, the electron transport layer 501, and the organic light-emitting layer 300 are stacked in sequence.

[0208] In some examples (4), the electron transport region 500 includes an electron transport layer 501 and an electron injection layer 502, wherein the cathode 200, the electron injection layer 502, the electron transport layer 501, and the organic light-emitting layer 300 are stacked in sequence.

[0209] In some examples (5), the electron transport region 500 includes an electron transport layer 501 and a hole blocking layer 503, wherein the cathode 200, the electron transport layer 501, the hole blocking layer 503, and the organic light-emitting layer 300 are stacked in sequence.

[0210] In some examples (6), the electron transport region 500 includes an electron transport layer 501, a hole blocking layer 503, and an electron injection layer 502, wherein the cathode 200, the electron injection layer 502, the electron transport layer 501, the hole blocking layer 503, and the organic light-emitting layer 300 are stacked in sequence.

[0211] The hole transport layer is prepared using hole transport materials. The general chemical formulas of some hole transport materials suitable for synergistic interaction with the aforementioned electron blocking materials are shown below:

[0212]

[0213] Ar2-Ar5 are each independently selected from aryl groups with 6-39 carbon atoms, heteroaryl groups with 5-60 carbon atoms, aryloxy groups with 6-60 carbon atoms, alkoxy groups with 1-39 carbon atoms, arylamino groups with 6-39 carbon atoms, and arylsilyl groups with 6-39 carbon atoms. These groups can be substituted (e.g., hydrogen atoms are substituted with deuterium) or unsubstituted. L2 is selected from single bonds, C6-C15 arylene groups, or C5-C15 heteroarylene groups; for example, L2 is selected from biphenyl groups.

[0214] By using a hole transport layer prepared from a hole transport material having the above-described chemical structure to synergize with an electron blocking layer prepared from an electron blocking material according to the embodiments of this disclosure, the advantages of reducing voltage and improving lifetime and efficiency are achieved.

[0215] Some hole transport materials that satisfy the above general chemical formula include, but are not limited to, the following:

[0216]

[0217]

[0218]

[0219] In this embodiment of the disclosure, the HOMO energy level of the hole transport layer is a, the HOMO energy level of the electron blocking layer is b, and the HOMO energy level of the organic light-emitting layer is c; a, b, and c satisfy: |ab|<|bc|.

[0220] The above arrangement makes the HOMO energy level of the hole transport layer and the HOMO energy level of the electron blocking layer closer together, and the gap between them is smaller. This helps to reduce the operating voltage of the organic electroluminescent device, thereby reducing energy consumption.

[0221] In this embodiment, the organic light-emitting layer includes a host light-emitting material and a dopant, wherein the hole mobility of the organic light-emitting layer is μh, the electron mobility is μe, and μh and μe satisfy μe / μh>2. By making μe / μh>2, it has the advantages of improving efficiency and reducing voltage.

[0222] Furthermore, this disclosure also provides a method for preparing an electron blocking material, the method comprising:

[0223] The electron-blocking material is obtained by performing a CN coupling reaction between the organohalide monomer corresponding to the M group and the amine monomer.

[0224] The chemical equation for this CN coupling reaction can be found below:

[0225] R1-X1+(R2) 3-n -N-(H) n =(R2) 3-n -N-(R1) n

[0226] Where n is 1 or 2, R1-X1 represents the organohalide monomer corresponding to the M group, and the halogen X1 can be Cl, Br or I, R2-N(H) x Represents amine monomers.

[0227] The CN coupling reactions involved in the embodiments of this disclosure include, but are not limited to: Buchwald or Ullmann coupling, silanization, phosphating, borylation, polycondensation, etc.

[0228] The catalysts involved can be adaptively designed according to the actual reaction raw materials and reaction scenarios. Some applicable catalysts include, but are not limited to, at least one of Pd2(dba)3 and P(t-Bu)3, some applicable bases include, but are not limited to, NaOt-Bu, and some applicable solvents include, but are not limited to, toluene.

[0229] Furthermore, the organohalide monomers corresponding to the M group can be obtained directly (e.g., when their chemical structure is relatively simple and their carbon chain is short), or they can be prepared by CC coupling reaction (e.g., when their chemical structure is relatively complex and their carbon chain is long).

[0230] In some examples, the organohalide monomers corresponding to the M group are prepared by the following method:

[0231] The organic halide monomer and the halogen-containing borate monomer are subjected to a C-C coupling reaction to obtain the organic halide monomer corresponding to the M group. The halogen contained in the organic halide monomer corresponding to the M group comes from the halogen in the borate monomer.

[0232] R 11 -X2+R 12 -B(OH)2=R 12 -R 11

[0233] Among them, R 11 -X2 represents an organohalide monomer, where halogen X2 can be Cl, Br, or I, R 12 -B(OH)2 represents a halogenated boric acid monomer, where R 12 It also includes the aforementioned halogen X1, that is, R 12 It can be abbreviated as R 13 +X1, where R 13 +R 11 This constitutes R1.

[0234] The CC coupling reactions involved in the embodiments of this disclosure include, but are not limited to: Suzuki, Negishi, Yamamoto, Grignard Cross, Stille, Heck coupling, etc.

[0235] The catalysts involved can be adaptively designed based on the actual reaction raw materials and reaction scenarios. Some applicable catalysts include, but are not limited to, Pb.

[0236] The preparation method of a specific electron blocking material is illustrated below. The chemical structural formula of the electron blocking material is shown in the figure below:

[0237]

[0238] Step 1: Based on CC coupling, prepare the organohalide monomer corresponding to the M group. The preparation method and steps are as follows:

[0239]

[0240] 20 mmol of reactant 1, 20 mmol of reactant 2, 1.16 g (1 mmol) of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4), and 2.5 g (18 mmol) of K2CO3 were dissolved in 240 mL of a mixed solution of THF and H2O (volume ratio 2:1). The resulting solution was then stirred at 70 °C for 5 hours. The reaction solution was cooled to room temperature, 160 mL of water was added, and the solution was extracted three times with 200 mL of diethyl ether. The obtained organic layer was dried over magnesium sulfate, and the solvent was evaporated from it to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain the organohalide monomer corresponding to the M group (expected yield 75%).

[0241] Step 2: Based on CN coupling, an electron blocking material is prepared. The preparation method and steps are as follows:

[0242]

[0243] In a reaction vessel, 10 mmol of the organohalide monomer corresponding to the M group and 15 mmol of the amine monomer were dissolved in 50 mL of toluene. Then, under a nitrogen atmosphere, 0.15 mmol of Pd₂(dba)₃, 0.8 mmol of P(t-Bu)₃, and 45 mmol of t-BuONa were added. After addition, the reaction temperature was slowly increased to 110 °C, and the mixture was stirred for 10 h. Distilled water was then added to the reaction solution, and the reaction solution was extracted with ethyl acetate. The extracted organic layer was then dried over magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material was purified by column chromatography to obtain an electron-blocking material (8.5 g, 80% yield).

[0244] Preferred embodiments of this disclosure will now be described in more detail. While preferred embodiments of this disclosure are described below, it should be understood that this disclosure can be implemented in various forms and should not be limited to the embodiments set forth herein. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with techniques or conditions described in the literature in the art or according to product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0245] Before describing the various specific embodiments and comparative examples below, the types of raw materials involved in these embodiments and comparative examples and their chemical structural formulas will be described respectively.

[0246] (1) The raw materials corresponding to the organic light-emitting layer include the light-emitting host material (GH) and the light-emitting layer dopant (GD), which are shown below:

[0247]

[0248] (2) In addition to the electron blocking materials 1-1, 1-2, 1-12, 1-19, 1-20, 1-22, 1-37, 1-38, 1-46, 1-65 (including CD3), 1-72 (including CD3), and 1-85, as well as the hole transport materials HT-1, HT-2, and HT-3 mentioned above, the materials corresponding to the hole transport region also include the following types of electron blocking materials, hole injection materials, and hole transport materials, as detailed below:

[0249]

[0250]

[0251] (3) The materials corresponding to the electron transport region include hole blocking materials (HBL-1), electron transport materials (ETL-1), and electron injection materials (Liq), as detailed below:

[0252]

[0253] Example 1

[0254] This embodiment provides a type of organic light-emitting device, the structure of which can be found in [reference needed]. Figure 1 It includes an anode 100, a hole injection layer 403 (HIL), a hole transport layer 401 (HTL), an electron blocking layer 402 (EBL), an organic light-emitting layer 300 (EML), a hole blocking layer 503 (HBL), an electron transport layer 501 (ETL), an electron injection layer 502 (EIL), and a cathode 200 arranged in sequence. In the organic light-emitting device of this type provided in Embodiment 1, the electron blocking layer (EBL) is set as a single layer.

[0255] Example 1 specifically includes Examples 1-10 and Comparative Examples 1-2. The materials and arrangements of each layer of the organic electronic light-emitting devices provided in the above examples and comparative examples are shown in Table 1.

[0256] Table 1

[0257] project anode HIL HTL EBL EML HBL ETL EIL cathode Example 1 ITO HT-1+PD HT-1 1-1 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 2 ITO HT-1+PD HT-1 1-12 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 3 ITO HT-1+PD HT-1 1-20 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 4 ITO HT-1+PD HT-1 1-22 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 5 ITO HT-2+PD HT-2 1-37 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 6 ITO HT-2+PD HT-2 1-38 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 7 ITO HT-2+PD HT-2 1-46 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 8 ITO HT-2+PD HT-2 1-65 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 9 ITO HT-2+PD HT-2 1-72 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Example 10 ITO HT-3+PD HT-3 1-85 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Comparative Example 1 ITO NPB+PD NPB EB-1 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag Comparative Example 2 ITO NPB+PD NPB EB-2 GH+GD HBL-1 ETL-1+Liq Yb Mg+Ag

[0258] For the HIL layer materials listed in Table 1, the PD material accounts for 2% of the total mass of the HIL layer materials. For the EML layer materials listed in Table 1, abbreviated as GH+GD, the formulations are as follows: by weight, GH-1:GH-2:GD-1 is 40:50:10, where GH-1 and GH-2 are the main materials, and GD is the luminescent material, thus forming an EML layer capable of emitting green light. For the ETL layer materials listed in Table 1, Liq accounts for 50% of the total mass of the ETL layer materials. For the cathode materials listed in Table 1, the mass ratio of Mg to Ag is 1:9.

[0259] Test Example 1

[0260] This test example tests the performance of each organic electronic light-emitting device provided in Example 1. The test items mainly involve the following three items. Furthermore, all the test data below are obtained after normalization based on the corresponding data of Comparative Example 1. Therefore, the units of the normalized data are all in _____.

[0261] (1.1) Operating voltage V, the actual unit is V, and the normalized unit is used in Test 1.

[0262] (1.2) Efficiency Eff, the actual unit is cd / A, and the normalized unit is used in Test 1.

[0263] (1.3) Lifespan LT, the actual unit is hours, and the normalized unit is % in Test 1. The LT test is obtained through lifespan testing equipment, with the initial brightness set to 1000 nits and at 15 mA / cm². 2 Under certain conditions, the time corresponding to when its brightness decays to 90% is measured.

[0264] This test example is based on the test data of Comparative Example 1, which is normalized. The test results are shown in Table 2.

[0265] Table 2

[0266] project V Eff LT Example 1 98.3 118.7 145.7 Example 2 99.4 117.7 157.4 Example 3 99.3 120.8 154.4 Example 4 99.6 121.9 157.0 Example 5 98.4 118.7 153.6 Example 6 97.5 119.8 156.1 Example 7 99.6 120.8 150.2 Example 8 96.8 121.9 151.1 Example 9 98.6 119.8 145.6 Example 10 98.8 118.7 148.4 Comparative Example 1 99.0 103 100 Comparative Example 2 100.0 100 115

[0267] As shown in Table 2, the organic electroluminescent devices provided in Examples 1-10 are based on the EBL material provided in this disclosure. On this basis, they synergistically work with the hole transport material provided in this disclosure to form a hole transport region. This significantly reduces the operating voltage of the organic electroluminescent devices and improves their lifespan and efficiency. Because the EBL material with a specific chemical structure is used, its HOMO energy level is at a suitable level, which can reduce the interface gap, facilitate hole injection, and thus allow holes and electrons to recombine more efficiently, reducing charge accumulation and device capacitance. This allows the green photonics to exhibit optimal color display performance when paired with blue and red photonics.

[0268] Example 2

[0269] This second embodiment provides another type of organic light-emitting device, the structure of which can be found in [reference needed]. Figure 2 It includes an anode 100, a hole injection layer 403 (HIL), a hole transport layer 401 (HTL), a first electron blocking layer 402 (EBL-1), a second electron blocking layer 402 (EBL-2), an organic light-emitting layer 300 (EML), a hole blocking layer 503 (HBL), an electron transport layer 501 (ETL), an electron injection layer 502 (EIL), and a cathode 200, arranged in sequence. In the organic light-emitting device of this type provided in Embodiment 2, the electron blocking layer is set as a double layer arranged in a stacked manner, with the thickness of EBL-1 being 30 nm and the thickness of EBL-2 being 10 nm.

[0270] Example 2 includes Examples 11-16 and Comparative Examples 3-4. The materials and arrangements of each layer of the organic light-emitting devices provided in the above examples and comparative examples are shown in Table 3.

[0271] Table 3

[0272]

[0273] For the HIL layer materials listed in Table 3, the PD material accounts for 2% of the total mass of the HIL layer materials. For the EML layer materials listed in Table 3, abbreviated as GH+GD, the formulations are as follows: by weight, GH-1:GH-2:GD-1 is 40:50:10, where GH-1 and GH-2 are the main materials, and GD is the luminescent material, thus forming an EML layer capable of emitting green light. For the ETL layer materials listed in Table 3, Liq accounts for 50% of the total mass of the ETL layer materials. For the cathode materials listed in Table 3, the mass ratio of Mg to Ag is 1:9.

[0274] Test Example 2

[0275] This second test example demonstrates the performance of each organic light-emitting device provided in Example 2. The test items and data compilation standards are the same as in Test Example 1. The test results are shown in Table 4.

[0276] Table 4

[0277] project V Eff LT Example 11 99.3 121.4 161.7 Example 12 100.5 120.3 174.7 Example 13 100.4 123.6 171.4 Example 14 100.7 124.7 174.3 Example 15 99.4 121.4 170.5 Example 16 98.5 122.5 173.3 Comparative Example 3 99.0 103 100 Comparative Example 4 100.0 100 115

[0278] As shown in Table 4, when the electron blocking layer is set to a double-layer structure, it can achieve the same effect as in Example 1. In particular, the organic electroluminescent device described in Example 2 shows a better lifespan.

[0279] The term "and / or" in the embodiments of this disclosure is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0280] The above description is only for the purpose of enabling those skilled in the art to understand the technical solutions disclosed herein, and is not intended to limit the scope of this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. An electron blocking material, characterized in that, The general chemical formula of the electron blocking material is shown in any of the following: 。 2. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and a light-emitting unit. The light-emitting unit is located between the anode and the cathode, and the light-emitting unit includes an organic light-emitting layer and hole transport regions and electron transport regions located on both sides of the organic light-emitting layer. The hole transport region includes a stacked hole transport layer and an electron blocking layer, wherein the electron blocking layer is prepared using the electron blocking material described in claim 1.

3. The organic electroluminescent device according to claim 2, characterized in that, The hole transport layer is prepared using a hole transport material, the general chemical formula of which is shown below: ； Ar2-Ar5 are each independently selected from aryl groups with 6-39 carbon atoms, heteroaryl groups with 5-60 carbon atoms, aryloxy groups with 6-60 carbon atoms, alkoxy groups with 1-39 carbon atoms, arylamino groups with 6-39 carbon atoms, and arylsilyl groups with 6-39 carbon atoms. L2 is selected from single bonds, C6-C15 aryl groups, or C5-C15 heteroaryl groups.

4. The organic electroluminescent device according to claim 3, characterized in that, The HOMO energy level of the hole transport layer is a, the HOMO energy level of the electron blocking layer is b, and the HOMO energy level of the organic light-emitting layer is c. a, b, and c satisfy: |ab| < |bc|.

5. The organic electroluminescent device according to claim 4, characterized in that, The organic light-emitting layer includes a light-emitting host material and a light-emitting layer dopant; The hole mobility of the organic light-emitting layer is μh, and the electron mobility is μe. μh and μe satisfy μe / μh>2.

6. A method for preparing an electron blocking material, characterized in that, The electron blocking material is as described in claim 1; The method for preparing the electron blocking material includes: performing a CN coupling reaction between an organic halide monomer corresponding to the M group and an amine monomer to obtain the electron blocking material; Wherein, the M group is a cyclopentyl group or a Si group in an electron blocking material.

7. The method for preparing the electron blocking material according to claim 6, characterized in that, The organohalide monomer corresponding to the M group is prepared by the following method: The organic halide monomer and the halogen-containing borate monomer are subjected to a C-C coupling reaction to obtain the organic halide monomer corresponding to the M group. The halogen contained in the organohalide monomer corresponding to the M group comes from the halogen in the boric acid monomer.

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