An organic electroluminescence device and a display device comprising the same

Abstract

This application provides an organic electroluminescent device comprising a light extraction layer containing a compound of general formula (I). The light extraction layer of this application has a high refractive index and a low refractive index difference, which, with the same light extraction layer thickness, can better balance the light extraction efficiency of organic electroluminescent devices for different colors of light, thus improving the overall light extraction efficiency. This application also provides a display device incorporating the organic electroluminescent device of this application.

Description

Technical Field

[0001] This application relates to the field of organic light-emitting display technology, and in particular to an organic electroluminescent device and a display device including the device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are multilayer organic thin-film structures, with the light-emitting layer located between the anode and cathode. When an electric current is applied, the light emitted from the light-emitting layer is transmitted through the transparent electrode side, and light loss occurs due to waveguide effects such as total internal reflection between the film layers. Adding a high-refractive-index light-extraction layer to the transparent electrode can significantly improve the light extraction efficiency.

[0003] The light extraction layer can be either an inorganic or organic compound. Inorganic compounds are characterized by their high refractive index, which is beneficial for light extraction, but the coating temperature is very high (>1000℃), which can damage organic components. Organic thin films have lower evaporation temperatures, offering greater advantages in processing compared to inorganic compounds. Organic light-emitting diode (OLED) devices primarily use organic light extraction materials that improve the light extraction efficiency of OLEDs. Refractive index is the most important indicator of light extraction materials; generally, the higher the refractive index of the light extraction layer, the higher the light extraction efficiency from the electrode to the light extraction layer, and the higher the luminous efficiency of the OLED.

[0004] Currently, the main material used for the light extraction layer in OLEDs is the aromatic amine compound (CN103828485A) from Hodogaya Chemicals in Japan. These compounds (such as compound 1-1) have a high refractive index; however, the refractive index increases with decreasing wavelength. Specifically, red light has a low refractive index, green light has a higher refractive index, and blue light has an even higher refractive index, with the difference between blue and red light being approximately 0.30. This difference in refractive index poses a significant challenge to the fabrication of red, green, and blue devices for OLED displays. Because the light extraction layer has a microcavity effect, it filters the wavelength of light emitted from the transparent electrode. An appropriate thickness of the light extraction layer enhances the light extraction effect, while an inappropriate thickness reduces the light extraction efficiency. Blue light has a short wavelength, so blue light devices require a thinner light extraction layer; green light devices require a thicker layer; and red light has the longest wavelength, so red light devices require the thickest light extraction layer. Furthermore, the refractive index of the light extraction layer material increases as the wavelength of transmitted light shortens due to the light dispersion effect. Therefore, the refractive index corresponding to blue light is always greater than that of red light, further increasing the difference in the optimal thickness of the light extraction layer for blue and red light. Since the light extraction layer is a common layer for red, green, and blue light, the same thickness is required in device fabrication. This makes it impossible to simultaneously achieve the optimal light extraction efficiency for all three colors, thus hindering the optimal performance of each color. When the thickness of the light extraction layer deviates from the optimal thickness, the device efficiency changes significantly. Additionally, different thicknesses of the light extraction layer filter out different wavelengths of light, resulting in a significant shift in the emitted light color. Therefore, the greater the difference in refractive index from blue to red light, the greater the difference in the optimal thickness for blue and red light, and the more difficult it is to balance the three colors in the manufacturing process of display devices.

[0005]

[0006] Summary of the Invention

[0007] In view of the above-mentioned problems of the prior art, the purpose of this application is to provide an organic electroluminescent device that achieves a smaller difference in refractive index between red, green and blue light and has a larger refractive index, thereby taking into account the best light extraction efficiency of red, green and blue light, while reducing the influence of the thickness of the light extraction layer on the light color shift.

[0008] A first aspect of this application provides an organic electroluminescent device comprising a light extraction layer, said light extraction layer comprising a compound of general formula (I):

[0009]

[0010] in,

[0011] Ar0 is selected from general formula (II), and X is selected from S or O;

[0012] Ar1 and Ar2 are each independently selected from unsubstituted or Ra-substituted C6-C. 30 aryl group, or unsubstituted or Ra-substituted C2-C 30 heteroaryl groups;

[0013] L1, L2, and L3 are each independently selected from single-bonded, unsubstituted, or Ra-substituted C6-C bonds. 30 arylene, or unsubstituted or Ra-substituted C2-C 30 heteroaryl;

[0014] The heteroatoms on the heteroaryl group and the heteroideal group are each independently selected from O, S, or N;

[0015] Each Ra is independently selected from deuterium, C1-C4 alkyl, phenyl, biphenyl, terphenyl, or naphthyl.

[0016] A second aspect of this application provides a display device that includes the organic electroluminescent device provided in this application.

[0017] The organic electroluminescent device provided in this application includes a light extraction layer comprising a compound of general formula (I). This extraction layer has a high refractive index and a low refractive index difference, which, with the same light extraction layer thickness, can better balance the light extraction efficiency of organic electroluminescent devices displaying different colors of light, thus improving the overall light extraction efficiency. The display device provided in this application exhibits excellent light extraction efficiency.

[0018] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0020] Figure 1 This is a schematic diagram of an organic electroluminescent device according to one embodiment of this application. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0022] A first aspect of this application provides an organic electroluminescent device comprising a light extraction layer, said light extraction layer comprising a compound of general formula (I):

[0023]

[0024] in,

[0025] Ar0 is selected from general formula (II), and X is selected from S or O;

[0026] Ar1 and Ar2 are each independently selected from unsubstituted or Ra-substituted C6-C. 30 aryl group, or unsubstituted or Ra-substituted C2-C 30 heteroaryl groups;

[0027] L1, L2, and L3 are each independently selected from single-bonded, unsubstituted, or Ra-substituted C6-C bonds. 30 arylene, or unsubstituted or Ra-substituted C2-C 30 heteroaryl;

[0028] The heteroatoms on the heteroaryl group and the heteroideal group are each independently selected from O, S, or N;

[0029] Each Ra is independently selected from deuterium, C1-C4 alkyl, phenyl, biphenyl, terphenyl, or naphthyl.

[0030] Preferably, Ar1 and Ar2 are each independently selected from unsubstituted or Ra-substituted C6-C. 18 aryl group, or unsubstituted or Ra-substituted C5-C 18 heteroaryl groups;

[0031] Preferably, L1, L2, and L3 are each independently selected from single-bonded, unsubstituted, or Ra-substituted C6-C bonds. 20 arylene, or unsubstituted or Ra-substituted C5-C 12 Hybrid aryl groups.

[0032] More preferably, Ar1 and Ar2 are each independently selected from the following groups:

[0033]

[0034] Wherein, Y is selected from O, S, or NR1; R1 is selected from C1-C5 alkyl groups, C3-C6 cycloalkyl groups, unsubstituted or Ra-substituted C6-C6 alkyl groups. 12 aryl group, or unsubstituted or Ra-substituted C5-C 12 heteroaryl groups;

[0035] More preferably, L1, L2, and L3 are each independently selected from single bonds or the following subunits:

[0036]

[0037] More preferably, Ar1 and Ar2 are each independently selected from the following groups:

[0038]

[0039] R1 is selected from C1-C5 alkyl groups, C3-C6 cycloalkyl groups, unsubstituted or Ra-substituted C6-C6 alkyl groups. 12 aryl group, or unsubstituted or Ra-substituted C2-C 12 Mixed aromatic compounds.

[0040] More preferably, L1, L2, and L3 are each independently selected from single bonds or the following subunits:

[0041]

[0042] Furthermore, at least two of Ar0, Ar1 and Ar2 are selected from the same group.

[0043] For example, compounds of general formula (I) may be selected from the following compounds:

[0044]

[0045]

[0046]

[0047] In this application, there are no particular restrictions on the type and structure of organic electroluminescent devices, which can be various types and structures of organic electroluminescent devices known in the art.

[0048] The organic electroluminescent device of this application can be a top-emitting device, which may include, for example, an anode electrode, a hole injection layer, a hole transport layer, an emitting layer, an electron transport layer, an electron injection layer, a transparent or semi-transparent cathode, and a light extraction layer in sequence on a substrate.

[0049] The organic electroluminescent device of this application can be a bottom-emitting structure, which may include, in order on a substrate, a light extraction layer, a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, an emitting layer, an electron transport layer, an electron injection layer, and a cathode electrode.

[0050] The organic electroluminescent device of this application can also be a light-emitting device with a dual-sided light-emitting structure, which may include, in sequence on a substrate, a light extraction layer, a transparent or semi-transparent anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a transparent or semi-transparent cathode, and a light extraction layer.

[0051] Additionally, an electron blocking layer may be present between the hole transport layer and the light-emitting layer, and a hole blocking layer may be present between the light-emitting layer and the electron transport layer. The structure of the organic electroluminescent device of the present invention is not limited to the specific structure described above; if necessary, the aforementioned layers may be omitted or added. This application does not impose any particular limitation on the thickness of the aforementioned layers, as long as the purpose of this application can be achieved. For example, the organic electroluminescent device may sequentially comprise, on a substrate, an anode (10-1000 nm) made of metal, a hole injection layer (5-20 nm), a hole transport layer (80-140 nm), an electron blocking layer (5-20 nm), a light-emitting layer (150-400 nm), a hole blocking layer (5-20 nm), an electron transport layer (300-800 nm), an electron injection layer (5-20 nm), a transparent or semi-transparent cathode (10-15 nm), and a light extraction layer.

[0052] Furthermore, the thickness of the light extraction layer is 50-90nm, preferably 60-80nm, and, considering more general cases, the thickness of the light extraction layer can be 3L, 5L, or even thicker.

[0053] Figure 1 A schematic diagram of an organic electroluminescent device according to one embodiment of this application is shown, wherein, from bottom to top, a substrate 1, an anode electrode 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7, a cathode electrode 8, and a light extraction layer 9 are arranged sequentially.

[0054] Understandable. Figure 1 The structure of a typical organic electroluminescent device is only schematically shown. This application is not limited to this structure. The light extraction layer 9 of this application can also be used in other types of organic electroluminescent devices.

[0055] In organic electroluminescent devices, the light extraction layer 9 can be made of inorganic compounds and organic compounds or a combination thereof. The organic compounds used in the prior art are mainly aromatic amines, for example, aromatic amines as shown in the following formula:

[0056]

[0057] These organic compounds have the advantage of high refractive index and excellent light extraction performance, but their molecular weight is also very large. When fabricating OLED elements via vapor deposition, large molecular weight organic compounds generally require high deposition temperatures, which may lead to high-temperature pyrolysis. Furthermore, as the wavelength of light increases, the refractive index of these compounds decreases significantly. Therefore, different light extraction layer thicknesses are needed for different colors of light to achieve high light extraction efficiency. However, in practical applications, especially in OLED displays, red, green, and blue light-emitting devices constitute a pixel. These three devices often use the same light extraction layer thickness, resulting in significant differences in the extraction efficiency of each color, i.e., large differences in light extraction rate, and also accompanied by a shift in the emitted color.

[0058] In organic light-emitting diodes (OLEDs), a light extraction layer is typically disposed on the electrode on the light-emitting side to improve light extraction efficiency. The refractive index of the light extraction layer is required to be greater than that of the electrode, and it must be able to transmit visible light. The light extraction layer of this application comprises a compound of general formula (I) and has a high refractive index; specifically, the refractive index of the light extraction layer of this application is ≥1.93. The high refractive index of the light extraction layer of this application can more effectively promote the light extraction efficiency of the organic light-emitting diode containing this light extraction layer, thereby improving the luminous efficiency of the device.

[0059] The material of the light extraction layer in this application exhibits a small change in refractive index as the wavelength of light increases, meaning it has a low refractive index difference. When used in red, green, and blue organic light-emitting diodes (OLEDs), using a light extraction layer of the same thickness allows for better balance of the optimal light extraction efficiency of OLEDs producing different colors of light, while also reducing the influence of the light extraction layer thickness on light color shift. Preferably, the difference between the red and blue refractive indices of the light extraction layer in this application is <0.27, more preferably <0.20. Unless otherwise specified, the difference between the red and blue refractive indices mentioned in this invention primarily uses the difference between the refractive indices at a red wavelength of 626 nm and the refractive indices at a blue wavelength of 460 nm as a reference.

[0060] In organic light-emitting diodes (OLEDs), the light extraction layer can be formed by various methods such as vacuum evaporation and spin coating, with vacuum evaporation being the preferred method. However, excessively high evaporation temperatures during vacuum evaporation can damage the OLED and may lead to high-temperature pyrolysis of the light extraction layer material. The evaporation temperature of the light extraction layer in this application is 330-400℃. This allows for the efficient formation of the light extraction layer through vacuum evaporation without causing high-temperature pyrolysis.

[0061] In the organic electroluminescent device of the present invention, except that the light extraction layer contains a compound of general formula (I) provided by the present invention, the other layers may use any material as used for the layers in the prior art.

[0062] For convenience, the following references Figure 1 The organic electroluminescent device described in this application is intended to illustrate the present application, but this does not imply any limitation on the scope of protection of this application.

[0063] In this application, the substrate 1 is not particularly limited and can be a conventional substrate used in organic electroluminescent devices in the prior art, such as glass, polymer materials, glass and polymer materials with thin-film transistor (TFT) components, etc.

[0064] In this application, the anode electrode 2 is not particularly limited and can be selected from anode electrodes known in the prior art. For example, it can be a metal, alloy, or conductive compound with a high work function (4 eV or greater). The metal can be Au, Ag, or other metals. The conductive transparent material can be selected from materials such as CuI, indium tin oxide (ITO), SnO2, and ZnO, or an amorphous material such as IDIXO (In2O3-ZnO) that can form a transparent conductive film can be used. The thickness of the anode electrode varies depending on the material used.

[0065] In this application, the material of the hole injection layer 3 is not particularly limited and can be made of hole injection materials known in the art, for example, hole transport material (HTM) can be selected as the hole injection material.

[0066] In a preferred embodiment, the hole injection layer 3 may further include a p-type dopant. The type of p-type dopant is not particularly limited, and various p-type dopants known in the art can be used. For example, the following p-type dopants can be used:

[0067]

[0068] In this application, there is no particular limitation on the amount of p-type dopant used, and it can be any amount known to those skilled in the art.

[0069] In this application, the material of the hole transport layer 4 is not particularly limited, and hole transport materials known to those skilled in the art can be used. The number of layers of the hole transport layer 4 is not particularly limited, and can be adjusted according to actual needs, as long as it meets the purpose of this application, for example, 1 layer, 2 layers, 3 layers, 4 layers or more.

[0070] For example, the hole transport material used in the hole injection layer and the hole transport layer may be selected from, but is not limited to, at least one of the following HT-1 to HT-32 compounds:

[0071]

[0072]

[0073]

[0074] In this application, the light-emitting layer 5 may comprise a blue light-emitting layer, a green light-emitting layer, or a red light-emitting layer. There are no particular limitations on the light-emitting material in the light-emitting layer 5; various light-emitting materials known to those skilled in the art can be used. For example, the light-emitting material may comprise a host material and a light-emitting dye.

[0075] In one embodiment of this application, the blue light host material may be selected from, but is not limited to, at least one of the following compounds: BH-1 to BH-36.

[0076]

[0077]

[0078] In one embodiment of this application, the green light host material may be selected from, but is not limited to, at least one of the following GPH-1 to GPH-81 compounds:

[0079]

[0080]

[0081]

[0082] In one embodiment of this application, the red light host material may be selected from, but is not limited to, at least one of the following RH-1 to RH-12 compounds:

[0083]

[0084] In one embodiment of this application, the light-emitting layer 5 employs electroluminescence technology, and the light-emitting dye in the light-emitting layer 5 is a fluorescent or phosphorescent dopant. The dopant may be selected from, but is not limited to, at least one of the following blue dyes BD01 to BD06, at least one of the following green dyes GD01 to GD05, or at least one of the following red dyes RPD-1 to RPD-30. The amount of the dopant is not particularly limited and can be any amount known to those skilled in the art.

[0085]

[0086]

[0087] In one embodiment of this application, the material of the electron transport layer 6 is not particularly limited, and electron transport materials known to those skilled in the art can be used. For example, at least one of the following compounds, but not limited to ET-1 to ET-62, can be used:

[0088]

[0089]

[0090]

[0091] In a preferred embodiment, the electron transport layer 6 may further include an n-type dopant. The type of n-type dopant is not particularly limited, and various n-type dopants known in the art can be used. For example, the following n-type dopants can be used:

[0092]

[0093] In this application, there is no particular limitation on the amount of the n-type dopant, and it can be any amount known to those skilled in the art.

[0094] In this application, the electron injection layer 7 is not particularly limited and can use electron injection materials known in the art, such as at least one selected from, but not limited to, materials such as 8-hydroxyquinoline-lithium (Liq), LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca in the prior art.

[0095] In this application, the cathode electrode 8 is not particularly limited and can be selected from, but is not limited to, materials such as magnesium-silver mixtures, LiF / Al, ITO, Al, metals, metal mixtures, and oxides.

[0096] This application also provides a display device including the organic electroluminescent device of this application. The display device includes, but is not limited to, a monitor, a television, a mobile communication terminal, a tablet computer, etc.

[0097] There are no particular limitations on the method for preparing the organic electroluminescent device of this application; any method known in the art can be used. For example, this application can be prepared using the following method:

[0098] (1) Clean the anode electrode 2 on the substrate 1 of the top-emitting OLED device. In the cleaning machine, the electrode is cleaned by chemical washing, water washing, brushing, high-pressure water washing, air knife and other steps, and then heated.

[0099] (2) A hole injection layer 3 is vacuum-deposited on the reflective anode electrode 2. The hole injection layer 3 contains a hole injection material and a p-type dopant.

[0100] (3) Hole transport material is vacuum-deposited on hole injection layer 3 as hole transport layer 4;

[0101] (4) A light-emitting layer 5 is vacuum-deposited on the hole transport layer 4, the light-emitting layer 5 containing a host material and a light-emitting dye;

[0102] (5) An electron transport layer 6 is vacuum-deposited on the light-emitting layer 5. The electron transport layer 6 contains an electron transport material and an n-type dopant.

[0103] (6) Vacuum evaporation of electron injection material on electron transport layer 6 to serve as electron injection layer 7;

[0104] (7) Vacuum evaporation of cathode material on electron injection layer 7 to serve as cathode electrode 8;

[0105] (8) Finally, a light extraction layer 9 is vacuum-deposited on the cathode electrode 8, the light extraction layer 9 containing a compound of general formula (I).

[0106] The above describes only the structure and fabrication method of a typical organic electroluminescent device. It should be understood that this application is not limited to this structure.

[0107] Synthesis Example:

[0108] Synthesis Example 1: Synthesis of Compound A2

[0109]

[0110] 100 mol of dibenzofuran-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of tetrakis(triphenylphosphine)palladium (Pd(PPh3)4). The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzofuran-4-boric acid.

[0111] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0112] 100 mmol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of dimethylformamide (DMF) were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M3.

[0113] 100 mol M3, 500 mmol SnCl2, 800 mL ethanol, and 2 mol ethyl acrylate (EA) were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M4.

[0114] 100 mmol of 4-chlorophenylboronic acid pinacol ester, 100 mmol of 2-bromopyridine, 41.4 g of potassium carbonate (300 mmol), 800 mmol of tetrahydrofuran (THF), and 200 mL of water were added to a reaction flask, along with 1 mol% of P(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M5. The amount of Pd(PPh3)4 added was 1 mol% of 2-bromopyridine.

[0115] 100 mmol of M4, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of palladium dibenzylacetone (Pd(dba)). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M6. The amount of Pd(dba) added was 1 mol% of M4.

[0116] 100 mmol of 3-chlorodibenzofuran, 100 mmol of M6, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder A2, in which the amount of Pd (dba) added was 1 mol% of M6.

[0117] 1H NMR(400MHz,Chloroform-d)δ8.81–8.76(m,1H),8.11–7.97(m,6H),7.94(d,J=7.2Hz,1H),7.75(dd,J=9.6,7.6Hz,1H),7.71–7.64(m,3H),7.58–7.53 (m,2H),7.53–7.45(m,3H),7.38(tdd,J=10.4,6.8,5.6Hz,2H),7.34–7.26 (m,2H),7.28–7.20(m,5H),7.17–7.11(m,2H),7.05(dd,J=9.2,7.2Hz,1H).

[0118] Synthesis Example 2: Synthesis of Compound A24

[0119]

[0120] 100 mol of dibenzofuran-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 100 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzofuran-4-boric acid.

[0121] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0122] 100 mol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of DMF were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0123] 100 mmol of M3, 500 mmol of SnCl2, 800 ml of ethanol, and 2 mol of EA were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M4.

[0124] 100 mmol of M4, 200 mmol of 3-bromodibenzothiophene, 200 mmol of sodium tert-butoxide, 1 mol% of tris(dibenzylacetone)dipalladium (Pd2(dba)3), and 4 mol% of 2-dicyclohexylphospho-2,4,6-triisopropylbiphenyl (X-PHOS) were added to a reaction flask, and the mixture was refluxed. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder A24. The amount of Pd2(dba)3 added was 1 mol% of M4, and the amount of X-PHOS added was 4 mol% of M4.

[0125] 1 H NMR(400MHz,Chloroform-d)δ8.18(dd,J=9.2,7.2Hz,2H),8.11–8.05(m,1H),8.07–8.01(m,2H),7.97–7.89(m,4H),7.75(dd,J=9.6,7.6Hz,1H),7 .71–7.66(m,1H),7.61(d,J=8.4Hz,2H),7.53–7.45(m,6H),7.38(td,J=8 .8,6.4Hz,1H),7.34–7.26(m,2H),7.25–7.20(m,2H),7.17–7.11(m,4H).

[0126] Synthesis Example 3: Synthesis of Compound A25

[0127]

[0128] 100 mol of dibenzothiophene-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 100 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzothiophene-4-boric acid.

[0129] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0130] 100 mol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of DMF were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0131] 100 mmol of M3, 500 mmol of SnCl2, 800 ml of ethanol, and 2 mol of EA were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M4.

[0132] 100 mmol of M4, 200 mmol of 3-bromodibenzothiophene, 200 mmol of sodium tert-butoxide, 1 mol% of Pd2(dba)3, and 4 mol% of X-PHOS were added to a reaction flask, and the mixture was refluxed. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder, A140. The amounts of Pd2(dba)3 and X-PHOS added were 1 mol% of M4 and 4 mol% of M4, respectively.

[0133] 1 H NMR(400MHz,Chloroform-d)δ8.32(dd,J=9.6,7.2Hz,1H),8.22–8.15(m,2H),8.12–8.07(m,1H),8.01–7.89(m,6H),7.70 –7.65(m,1H),7.64–7.59(m,3H),7.49(dd,J=10.4,7.2Hz,6H),7.35–7.26(m,2H),7.25–7.20(m,2H),7.17–7.11(m,4H).

[0134] Synthesis Example 4: Synthesis of Compound A28

[0135]

[0136] 100 mol of dibenzothiophene-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 100 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzothiophene-4-boric acid.

[0137] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0138] 100 mol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of DMF were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0139] 100 mmol of M3, 500 mmol of SnCl2, 800 ml of ethanol, and 2 mol of EA were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M4.

[0140] 100 mmol of 2-chlorobenzoxazole, 100 mmol of 4-chlorophenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M5. The amount of Pd(PPh3)4 added was 1 mol% of 2-chlorobenzoxazole.

[0141] 100 mmol of 3-chlorodibenzothiophene, 100 mmol of M6, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder A28, in which the amount of Pd (dba) added was 1 mol% of M6.

[0142] 1 H NMR(400MHz,Chloroform-d)δ8.25–8.15(m,2H),8.13–8.05(m,1H),8.00–7.89(m,4H),7.70–7.65(m,2H),7.64–7.59( m,2H),7.53–7.45(m,6H),7.35–7.28(m,5H),7.29(s,1H),7.28(d,J=7.2Hz,1H),7.25–7.20(m,2H),7.17–7.11(m,3H).

[0143] Synthesis Example 5: Synthesis of Compound A59

[0144]

[0145] 100 mol of dibenzothiophene-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 100 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzothiophene-4-boric acid.

[0146] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0147] 100 mol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of DMF were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0148] 100 mmol of M3, 500 mmol of SnCl2, 800 ml of ethanol, and 2 mol of EA were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M4.

[0149] 100 mmol of 5-chloropyridine-2-boric acid, 100 mmol of bromobenzene, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M7. The amount of Pd(PPh3)4 added was 1 mol% of 5-chloropyridine-2-boric acid.

[0150] 100 mmol of M4, 100 mmol of M7, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M6. The amount of Pd (dba) added was 1 mol% of M4.

[0151] 100 mmol of 3,7-dibromodibenzothiophene, 100 mmol of pyridine 2-borate, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M5. The amount of Pd(PPh3)4 added was 1 mol% of 3,7-dibromodibenzothiophene.

[0152] 100 mmol of M5, 100 mmol of M6, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder A59, in which the amount of Pd (dba) added was 1 mol% of M5.

[0153] 1 H NMR(400MHz,Chloroform-d)δ8.81–8.76(m,1H),8.70(d,J=8.4Hz,1H),8.49(d,J=7.6Hz,1H),8.27–8.19(m,2H),8.12–8.05(m,4H), 8.01–7.92(m,5H),7.89–7.83(m,2H),7.71–7.64(m,3H),7.53–7.45(m,4H),7.37–7.26(m,3H),7.28–7.21(m,3H),7.17–7.11(m,3H).

[0154] Synthesis Example 6: Synthesis of Compound A60

[0155]

[0156] 100 mol of dibenzofuran-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of (Pd(PPh3)4). The reaction was carried out at 100 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzofuran-4-boric acid.

[0157] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0158] 100 mol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of DMF were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M3.

[0159] 100 mmol of M3, 500 mmol of SnCl2, 800 ml of ethanol, and 2 mol of EA were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M4.

[0160] 100 mmol of 5-chloropyridine-2-boric acid, 100 mmol of bromobenzene, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M7. The amount of Pd(PPh3)4 added was 1 mol% of 5-chloropyridine-2-boric acid.

[0161] 100 mmol of M, 100 mmol of M7, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M6. The amount of Pd (dba) added was 1 mol% of M4.

[0162] 100 mmol of 3,7-dibromodibenzofuran, 100 mmol of pyridine 2-borate, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M5. The amount of Pd(PPh3)4 added was 1 mol% of 3,7-dibromodibenzofuran.

[0163] 100 mmol of M5, 100 mmol of M6, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, A60, in which the amount of Pd (dba) added was 1 mol% of M5.

[0164] 1 H NMR(400MHz,Chloroform-d)δ8.81–8.76(m,1H),8.70(d,J=8.4Hz,1H),8.11–8.05 (m,2H),8.01–7.93(m,4H),7.90–7.84(m,2H),7.83(dd,J=8.8,7.2Hz,1H),7.75(d d,J=9.6,7.6Hz,1H),7.72–7.63(m,5H),7.56(d,J=8.8Hz,1H),7.49(ddd,J=8.8,6 .4,3.6Hz,4H),7.44–7.26(m,5H),7.17–7.11(m,4H),7.06(dd,J=7.6,6.4Hz,1H).

[0165] Synthesis Example 7: Synthesis of Compound A61

[0166]

[0167] 100 mol of dibenzothiophene-4-boric acid, 100 mmol of o-bromonitrobenzene, 41.4 g of potassium carbonate (300 mmol), 1000 ml of toluene, 800 ml of ethanol, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 100 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M1. The amount of Pd(PPh3)4 added was 1 mol% of dibenzothiophene-4-boric acid.

[0168] 100 mmol of M1, 300 mmol of triphenylphosphine, and 800 mL of o-dichlorobenzene were added to a reaction flask. The reaction was carried out at 100 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M2.

[0169] 100 mmol of M2, 100 mmol of p-fluoronitrobenzene, 60.1 g of cesium carbonate (300 mmol), and 800 mL of DMF were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M3.

[0170] 100 mol M3, 500 mmol SnCl2, 800 mL ethanol, and 2 mol EA were added to a reaction flask and refluxed for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and the obtained solid was purified by recrystallization from toluene to obtain a white powder M4.

[0171] 100 mmol of 3-bromodibenzofuran, 100 mmol of 4-chlorophenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was completed, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and then purified by recrystallization from toluene to obtain a white powder M5. The amount of Pd(PPh3)4 added was 1 mol% of 3-bromodibenzofuran.

[0172] 100 mmol of M4, 100 mmol of M5, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, M7. The amount of Pd (dba) added was 1 mol% of M4.

[0173] 100 mmol of 2-bromopyridine, 100 mmol of 4-chlorophenylboronic acid, 41.4 g of potassium carbonate (300 mmol), 800 ml of THF, and 200 ml of water were added to a reaction flask, along with 1 mol% of Pd(PPh3)4. The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, and the organic phase was concentrated to obtain a white solid. The solid was filtered, washed with water, and purified by recrystallization from toluene to obtain a white powder M6. The amount of Pd(PPh3)4 added was 1 mol% of 2-bromopyridine.

[0174] 100 mmol of M6, 100 mmol of M7, 28.83 g of sodium tert-butoxide (300 mmol), and 800 ml of xylene were added to a reaction flask, along with 1 mol% of Pd (dba). The reaction was carried out at 120 °C for 12 h. After the reaction was complete, the reaction was stopped, and the reactants were cooled to room temperature. Water was added, the mixture was filtered, washed with water, and the resulting solid was purified by recrystallization from toluene to obtain a white powder, A61, in which the amount of Pd (dba) added was 1 mol% of M7.

[0175] 1 H NMR(400MHz,Chloroform-d)δ8.81–8.76(m,1H),8.22(dd,J=10.8,8.4Hz,1H),8.12–8 .07(m,1H),8.08–8.03(m,2H),8.00–7.92(m,3H),7.90(d,J=8.0Hz,1H),7.72(d,J=7.2 Hz,1H),7.70–7.64(m,3H),7.62(d,J=6.4Hz,1H),7.60–7.45(m,7H),7.37(td,J=8.8,5 .6Hz,1H),7.34–7.27(m,2H),7.27–7.20(m,5H),7.23–7.17(m,2H),7.17–7.11(m,2H).

[0176] Other compounds in this application can be synthesized by selecting suitable raw materials according to the ideas in the above-described synthetic examples 1-7, or by selecting any other suitable methods and raw materials.

[0177] Example 1

[0178] A reflective anode electrode is disposed on a glass substrate. The anode electrode is an ITO electrode with a thickness of 130 nm.

[0179] Then, a 10 nm thick hole injection layer is vacuum-deposited on the anode electrode. The hole injection layer is made of HT-11 and 3% by mass of p-type dopant p-1. The deposition rate is 0.1 nm / s. The selected hole injection layer material and p-type dopant are as follows:

[0180]

[0181] Then, a hole transport layer with a thickness of 112 nm is vacuum-deposited on the hole injection layer. The material of the hole transport layer is the aforementioned HT-32, and the deposition rate is 0.1 nm / s.

[0182] Then, a light-emitting layer is vacuum-deposited on top of the hole transport layer. The light-emitting layer includes a host material BH-1 and a luminescent dye BD01, and is deposited using a multi-source co-evaporation method. The evaporation rate of the host material BH-1 is adjusted to 0.1 nm / s, and the evaporation rate of the dye BD01 is 3% of the evaporation rate of the host material. The total film thickness is 20 nm. The host material and the luminescent dye are as follows:

[0183]

[0184] Then, an electron transport layer with a thickness of 35 nm is vacuum-deposited on the light-emitting layer. The electron transport layer contains electron transport material ET-58 and n-type dopant n-1, wherein the content of n-type dopant is 50 mol%. The electron transport material and n-type dopant used are as follows:

[0185]

[0186] Then, an electron injection layer with a thickness of 40 nm is vacuum-deposited on the electron transport layer. The material of the electron injection layer is Liq, and the deposition rate is 0.1 nm / s.

[0187] Then, a cathode electrode with a thickness of 18 nm is vacuum-deposited on the electron injection layer. The cathode electrode is made of cathode material with a Mg to Ag molar ratio of 1:9, and the deposition rate is 1 nm / s.

[0188] Finally, a light extraction layer with a thickness of 50 nm is vacuum-deposited on the cathode electrode, and the material of the light extraction layer is A24.

[0189] The organic electroluminescent device in this embodiment emits blue light.

[0190] Examples 2-4

[0191] Except for changing the thickness of the light extraction layer as shown in Table 1, everything else is the same as in Example 1.

[0192] Example 5

[0193] Except for replacing the main material in the luminescent layer with GPH-82 and the luminescent dye with GD01, everything else is the same as in Example 2.

[0194]

[0195] The organic electroluminescent device in this embodiment emits green light.

[0196] Examples 6-8

[0197] Except for changing the thickness of the light extraction layer as shown in Table 1, the rest is the same as in Example 5.

[0198] Example 9

[0199] Except for replacing the main material in the luminescent layer with RH-12 and the luminescent dye with RPD-30, everything else is the same as in Example 2.

[0200]

[0201] The organic electroluminescent device in this embodiment emits red light.

[0202] Examples 10-12

[0203] Except for changing the thickness of the light extraction layer as shown in Table 1, the rest is the same as in Example 9.

[0204] Examples 13-30

[0205] Except for replacing A24 with A2, A25, A28, A59, A60 and A61 respectively, the rest are the same as the above embodiments with a light extraction layer thickness of 70nm, as shown in Table 1.

[0206] The data and test results for Examples 1-30 are shown in Tables 1 and 2.

[0207] Comparative Example 1

[0208] Except for replacing A24 with compound 1-1, the rest is the same as in Example 1.

[0209]

[0210] Comparative Examples 2-4

[0211] Except for changing the thickness of the light extraction layer as shown in Table 1, everything else is the same as in Comparative Example 1.

[0212] Comparative Example 5

[0213] Except for replacing A24 with compound 1-1, the rest is the same as in Example 5.

[0214] Comparative Examples 6-8

[0215] Except for changing the thickness of the light extraction layer as shown in Table 1, everything else is the same as in Comparative Example 5.

[0216] Comparative Example 9

[0217] Except for replacing A24 with compound 1-1, the rest is the same as in Example 9.

[0218] Comparative Examples 10-12

[0219] Except for changing the thickness of the light extraction layer as shown in Table 1, everything else is the same as Comparative Example 9.

[0220] The data and test results for Comparative Examples 1-12 are shown in Tables 1 and 2.

[0221] Determination of refractive index

[0222] The measuring instrument was a Version-1.0.1.4 spectroscopic ellipsometer from Radiation Technology; the glass substrate size was 200 mm × 200 mm, and the material film thickness was 80 nm. The refractive index of the compound was measured at different wavelengths.

[0223] Performance testing of organic electroluminescent devices

[0224] Specifically, the BJV testing system was used to test the current efficiency and CIE color coordinates of the organic electroluminescent device.

[0225] For blue light devices, the blue light index (BI) is used to assess their luminous efficiency, while the CIEy value mainly evaluates the saturation of blue light color. The blue light index is obtained by dividing the current efficiency of the blue light device by the CIEy value. A larger CIEy value indicates a red shift in blue light color, and a smaller CIEy value indicates a blue shift in blue light color. Current efficiency is used to evaluate the luminous efficiency of green and red light devices. For color changes in green and red light devices, the CIEx value is mainly used for evaluation. A larger CIEx value indicates a red shift in emission, and a smaller CIEx value indicates a blue shift in emission.

[0226] Table 1 Comparison of component performance in the examples and comparative examples.

[0227]

[0228]

[0229] Table 2 Comparison of Relative Refractive Index (n)

[0230]

[0231] As can be seen from Table 2, the refractive index difference between blue and red light for 1-1 is as high as 0.31, while the refractive index difference between blue and red light for compounds A2, A24, A25, A28, A59, A60 and A61 of this application is less than 0.27.

[0232] For the 1-1 blue LED device, increasing the light extraction layer thickness from 50nm to 60nm increases the blue light index from 110 to 114. However, increasing the thickness from 60nm to 80nm decreases the blue light index from 114 to 103, a decrease of 9.6%. This indicates that the optimal light extraction layer thickness for the 1-1 blue LED device is around 60nm. Similarly, the optimal light extraction layer thickness for the A24 blue LED device is also around 60nm. Increasing the light extraction layer thickness from 50nm to 60nm increases the blue light index from 113 to 124. However, increasing the thickness from 60nm to 80nm decreases the blue light index from 124 to 116, a decrease of 6.5%. At the optimal light extraction layer thickness of 60nm, the BI of the A24 is 8.8% higher than that of the 1-1 device. Furthermore, as the thickness of the light extraction layer increased from 60nm to 80nm, the CIEy of the blue light device of 1-1 increased from 0.089 to 0.096, a rise of 0.007, while the CIEy of the blue light device of A24 increased from 0.085 to 0.089, a rise of 0.004. This indicates that A24, as a light extraction layer material, exhibits less variation in light color with thickness compared to 1-1, and demonstrates better stability in light color.

[0233] For the green light-emitting device 1-1, increasing the light extraction layer thickness from 60nm to 90nm increased the current efficiency from 105cd / A to 108cd / A, then decreased it to 96cd / A, with the optimal thickness around 70nm. From 70nm to 90nm, the current efficiency decreased by 11.1%, and the CIEx increased from 0.239 to 0.250, a rise of 0.011. Similarly, the optimal light extraction layer thickness for the A24 green light-emitting device is also around 70nm. Increasing the thickness from 70nm to 90nm reduced the current efficiency from 112cd / A to 105cd / A, a decrease of 6.3%, and the CIEx increased from 0.238 to 0.246, a rise of 0.008, indicating weaker color shift than 1-1. At the optimal light extraction layer thickness of 70nm, the current efficiency of A24 was 3.7% higher than that of 1-1.

[0234] For the 1-1 red light device, increasing the light extraction layer thickness from 60nm to 90nm increases the current efficiency from 45cd / A to 52cd / A, then decreases it to 47cd / A. Its optimal light extraction layer thickness is around 80nm. From 60nm to 80nm, the current efficiency increases by 15.6%. The optimal light extraction layer thickness for the A24 red light device is also around 80nm. From 60nm to 80nm, the current efficiency increases from 48cd / A to 55cd / A, an increase of 14.6%, and the CIEx changes from 0.678 to 0.682, an increase of 0.04. In contrast, the CIEx of the 1-1 device increases by only 0.06.

[0235] The comparison of devices with different thicknesses of 1-1 and A24 shows that, compared to 1-1 as the light extraction layer material, A24, as the light extraction layer material, not only improves the efficiency of blue, green, and red devices, but also makes the efficiency of blue, green, and red devices less affected by changes in the thickness of the light extraction layer, and the corresponding changes in the CIE coordinates of the emitted light are also relatively small. Clearly, the thickness of A24 as the light extraction layer material has a weaker impact on the luminous efficiency and emission color of the device. Therefore, with a light extraction layer thickness in the range of 60-80nm, a good balance can be achieved in the efficiency of red, green, and blue colors, while the emission color can be well maintained.

[0236] Examples 13-15, 16-18, 19-21, 22-24, 25-27, and 28-30 used A2, A25, A28, A59, A60, and A61 as light extraction layer materials, respectively. The refractive index difference between blue light (460nm) and red light (626nm) of these materials was less than 0.27. These devices also exhibited good photoelectric performance.

[0237] Because the refractive index difference between blue and red light is small in the compounds of this application, using these compounds, optimal light extraction efficiency can be achieved for organic electroluminescent devices emitting different colors of light with minimal difference in the thickness of the light extraction layer. With the same light extraction layer thickness, the light extraction efficiency of organic electroluminescent devices emitting different colors of light can be better balanced, thus improving the overall light extraction efficiency while maintaining a smaller shift in the emitted color.

[0238] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. An organic electroluminescent device comprising a light extraction layer, said light extraction layer comprising a general formula ( Compounds of: in, Ar0 is selected from general formula (II), and X is selected from S or O; Ar1 and Ar2 are each independently selected from the following groups: ， in, Y is selected from O, S, or NR1; R1 is selected from C1-C5 alkyl groups, C3-C6 cycloalkyl groups, unsubstituted or Ra-substituted C6-C6 alkyl groups. 12 aryl group, or unsubstituted or Ra-substituted C5-C 12 heteroaryl groups; L1, L2, and L3 are each independently selected from single bonds or the following subunits: ； The heteroatoms on the heteroaryl group are each independently selected from O, S, or N; Each of the Ra groups is independently selected from deuterium, C1-C4 alkyl, phenyl, biphenyl, terphenyl, or naphthyl groups; The difference between the red and blue refractive indices of the light extraction layer is <0.

27.

2. The organic electroluminescent device according to claim 1, wherein, Ar1 and Ar2 are each independently selected from the following groups: ， R1 is selected from C1-C5 alkyl groups, C3-C6 cycloalkyl groups, unsubstituted or Ra-substituted C6-C6 alkyl groups. 12 aryl group, or unsubstituted or Ra-substituted C2-C 12 heteroaryl groups; L1, L2, and L3 are each independently selected from single bonds or the following subunits: 。 3. The organic electroluminescent device according to claim 1, wherein, At least two of Ar0, Ar1 and Ar2 are selected from the same group.

4. The organic electroluminescent device according to claim 1, wherein, The general formula ( The compounds are selected from the following compounds: 。 5. The organic electroluminescent device according to claim 1, wherein, The refractive index of the light extraction layer is ≥1.

93.

6. The organic electroluminescent device according to claim 1, wherein, The difference between the red light refractive index and the blue light refractive index of the light extraction layer is <0.

20.

7. The organic electroluminescent device according to claim 1, wherein, The thickness of the light extraction layer is 50-90 nm.

8. The organic electroluminescent device according to claim 1, wherein, The thickness of the light extraction layer is 60-80 nm.

9. A display device comprising the organic electroluminescent device according to any one of claims 1 to 8.

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