An organic electroluminescent compound, and a composition and an organic electroluminescent device comprising the same

Abstract

The application provides an organic electroluminescent compound, a composition containing the same and an organic electroluminescent device. The structural general formula of the organic electroluminescent compound is shown in formula I. The organic electroluminescent compound can not only enhance the electron-transporting ability, adjust the electron mobility of the molecule, but also make the material film more stable and improve the service life of the organic electroluminescent device. In addition, the application also provides a composition containing the same. The composition can not only regulate the carrier transport balance, but also reduce the energy loss through interaction. The composition provided by the application is applied to a light-emitting layer of a blue organic electroluminescent device. The light-emitting layer material can improve the light-emitting efficiency of the blue organic electroluminescent device, prolong the service life of the blue organic electroluminescent device and overcome the defects of the prior art.

Description

Technical Field

[0001] This invention belongs to the field of OLED technology, and particularly relates to an organic electroluminescent compound, a composition comprising the same, and an organic electroluminescent device. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are a display lighting technology that has gradually developed in recent years. Especially in the display industry, OLED displays have attracted widespread attention due to their advantages such as high response time, high contrast ratio, and flexibility. Currently, the pixel units of full-color OLED displays on the market are composed of red, green, and blue primary colors. According to the principle of the three primary colors, various colors can be generated by controlling the monochromatic gray levels of red, green, and blue in the sub-pixel units, thus displaying a color image. Among the three-color light-emitting devices, blue light materials have higher energy than red and green light materials. This energy can be transferred to lower-energy organic light-emitting materials such as green, yellow, and red light. Furthermore, according to the principle of the three primary colors, blue light emission is the foundation for achieving white and color displays. Therefore, blue light materials are a key research focus in the field of organic optoelectronic materials.

[0003] Currently, almost all blue organic light-emitting devices utilize a host-guest doping system for their luminescent layers, achieving electroluminescence by combining a host material with a guest dopant. Generally, the energy level of the host material's luminescence must be higher than that of the guest dopant. The luminescent layer, containing the host material, is the primary region for carrier recombination. Carriers recombine in the luminescent layer to generate excitons. The host material absorbs the energy of the excitons and transfers it to the guest dopant via Forster and Dexter energy transfer mechanisms, thus exciting the guest dopant and causing it to emit light.

[0004] However, existing blue organic light-emitting devices (OLEDs) primarily use single-host materials for their emitting layers. Single-host materials cannot effectively control the transport of holes and electrons; typically, holes transport faster than electrons, easily leading to carrier recombination imbalance. In severe cases, this can affect the exciton recombination region, thereby reducing the luminous efficiency of OLEDs. Furthermore, commonly used blue boron-nitrogen doped materials, due to their planar core structure, often experience dopant molecule aggregation during film formation, resulting in concentration quenching. This severely impacts the efficiency and lifetime of OLEDs. Therefore, there is an urgent need to develop a new emitting layer material for OLEDs. Summary of the Invention

[0005] In view of this, the present invention provides an organic electroluminescent compound, a composition comprising the same, and an organic electroluminescent device. This organic electroluminescent compound not only enhances electron-donating ability and regulates the electron mobility of molecules, but also makes the material film more stable and improves the lifetime of the organic electroluminescent device. Furthermore, the composition comprising the same can regulate carrier transport balance through interactions and reduce energy loss. When the composition provided by the present invention is applied to the light-emitting layer of a blue organic electroluminescent device, the light-emitting layer material can improve the luminous efficiency of the blue organic electroluminescent device and extend its lifetime, overcoming the shortcomings of the prior art.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] The first aspect of this invention provides an organic electroluminescent compound, the general structural formula of which is shown in Formula I:

[0008]

[0009] The Ar1 is selected from aryl groups with 6 to 60 carbon atoms, substituted or unsubstituted, and fused-ring aryl groups with 10 to 60 carbon atoms, substituted or unsubstituted.

[0010] The L1 and L2 are independently selected from aryl groups with 6 to 30 carbon atoms that are single-bonded, substituted, or unsubstituted.

[0011] The Ar2 is X1 and X2 are selected from C or N, and R0 and R1 represent monosubstituents to the most permissible substituents, which are independently selected from hydrogen, deuterium, alkyl groups with 1 to 10 carbon atoms (substituted or unsubstituted), and alkenyl groups with 2 to 10 carbon atoms (substituted or unsubstituted). Two or more substituents can be bonded to each other through linking groups or single bonds to form benzene rings or fused rings.

[0012] When any one of Ar1, L1, L2, R0, and R1 contains a substituent, the substituent of Ar1, L1, L2, R0, and R1 may be one or more, and each may be independently selected from deuterium, aryl with 6 to 30 carbon atoms, or fused-ring aryl with 10 to 30 carbon atoms.

[0013] The first aspect of this invention provides an organic electroluminescent compound containing an anthracene fragment and a pyridylcarbazole fragment. The anthracene fragment has strong conjugation, enabling it to transport both holes and electrons, while the carbazole group has strong electron-donating ability. By introducing a pyridyl group onto the carbazole and then linking the pyridylcarbazole fragment to the anthracene fragment, this invention not only enhances the electron-donating ability of the compound and regulates the electron mobility of the molecule, but also makes the film formation of the material more stable and improves the lifetime of the organic electroluminescent device.

[0014] In conjunction with the first aspect, the Ar2 is selected from... Any one of them.

[0015] In conjunction with the first aspect, the organic electroluminescent compound is selected from any one of the following compounds:

[0016]

[0017]

[0018]

[0019] A second aspect of the present invention provides a composition comprising the compound of formula I as described in the first aspect, further comprising the compound of formula II containing a furan structure and the compound of formula III containing a sterically hindered and thiophene structure:

[0020]

[0021] The Ar3 is selected from aryl groups with 6 to 60 carbon atoms, substituted or unsubstituted, and fused-ring aryl groups with 10 to 60 carbon atoms, substituted or unsubstituted.

[0022] R2 represents a single substituent to the maximum permissible substituent, each independently selected from hydrogen or deuterium;

[0023] The L3 and L4 are independently selected from arylene groups with 6 to 30 carbon atoms that are single-bonded, substituted, or unsubstituted.

[0024] The Ar4 is R3 and R4 represent monosubstituted to the most permissible substituents, each independently selected from hydrogen, deuterium, alkyl with 1 to 10 carbon atoms (substituted or unsubstituted), and alkenyl with 2 to 10 carbon atoms (substituted or unsubstituted). Two or more substituents can be bonded to each other through linking groups or single bonds to form benzene rings or fused rings.

[0025] When any one of Ar3, L3, L4, R3, and R4 contains a substituent, the substituent of Ar3, L3, L4, R3, and R4 may be one or more, and each may be independently selected from deuterium, aryl groups having 6 to 30 carbon atoms, and fused-ring aryl groups having 10 to 30 carbon atoms.

[0026]

[0027] R5, R6, and R8 independently represent monosubstituents to the most permissible substituents, and are each independently selected from any one or any combination of hydrogen, deuterium, alkyl groups with 1 to 10 carbon atoms (substituted or unsubstituted), cycloalkyl groups with 3 to 30 carbon atoms (substituted or unsubstituted), aryl groups with 6 to 30 carbon atoms (substituted or unsubstituted), and aromatic amino groups with 12 to 30 carbon atoms (substituted or unsubstituted). Two or more substituents can be bonded to each other through linking groups or single bonds to form aliphatic rings, aromatic rings, heteroaromatic rings, fused rings, or fused heterocycles.

[0028] R7 represents a cycloalkyl group with 3 to 30 carbon atoms that has been substituted or not substituted, or a bridged cycloalkyl group with 4 to 30 carbon atoms that has been substituted or not substituted. When R7 has substituents, the substituents of R7 can be one or more, and can be independently selected from alkyl groups with 1 to 10 carbon atoms or aryl groups with 6 to 30 carbon atoms. Two or more substituents can be bonded to each other through linking groups or single bonds to form an aliphatic ring.

[0029] R9 represents a single substituent to the most permissible substituent, each independently selected from any one or any combination of hydrogen, deuterium, alkyl groups with 1 to 10 carbon atoms (substituted or unsubstituted), and aryl groups with 6 to 30 carbon atoms (substituted or unsubstituted). Two or more substituents can be bonded to each other by a linking group or a single bond to form an aliphatic ring, aromatic ring, heteroaromatic ring, fused ring, or fused heterocyclic ring.

[0030] When any one of R5, R6, R8, and R9 contains a substituent, the substituent of R5, R6, R8, and R9 may be one or more, and may be independently selected from any one of deuterium, alkyl groups having 1 to 10 carbon atoms, and cycloalkyl groups having 3 to 30 carbon atoms.

[0031] The compound of Formula I provided by this invention contains a pyridylcarbazole structure, which has electron-donating properties and can adjust the electron cloud density on the anthracene ring, thus facilitating hole transport. The compound of Formula II provided by this invention contains a furan structure, which has electron-withdrawing properties and can adjust the electron cloud density on the anthracene ring, thus facilitating electron transport. Compared with fused-ring anthracene compounds, the mixture formed by the interaction between the compound of Formula I and the compound of Formula II is more suitable for electron and hole transport and can significantly balance carrier transport. The composition provided by this invention defines the structures of the compound of Formula I, the compound of Formula II, and the compound of Formula III respectively. Through the interaction between the compound of Formula III and the compounds of Formula I and Formula II, the molecules of the compound of Formula III in the composition can be horizontally distributed in the mixture composed of the compounds of Formula I and Formula II. This makes the light emitted by the compound of Formula III more inclined to be emitted in a direction perpendicular to the substrate, thereby reducing the energy loss caused by light during transmission.

[0032] In conjunction with the second aspect, in the composition, the mass ratio of the compound shown in Formula I, the compound shown in Formula II, and the compound shown in Formula III is 49:49:2.

[0033] In conjunction with the second aspect, in the composition, Ar4 is selected from... Any one of them.

[0034] In conjunction with the second aspect, the compound represented by Formula II is selected from any one of the following compounds:

[0035]

[0036]

[0037]

[0038]

[0039] In conjunction with the second aspect, the compound represented by Formula III is selected from any one of the structures represented by Formula III-1 to Formula III-2 below:

[0040]

[0041] In conjunction with the second aspect, the compound represented by Formula III is selected from any one of the following compounds:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047] A third aspect of the present invention provides an organic electroluminescent device, comprising a first electrode disposed sequentially on a substrate, a second electrode disposed opposite to the first electrode, and one or more organic functional layers disposed between the first electrode and the second electrode.

[0048] The organic functional layer includes a light-emitting layer; the light-emitting layer includes the composition described above.

[0049] In conjunction with the third aspect, the light-emitting layer includes a host material and a dopant material. The host material includes one or more compounds represented by chemical formula I and one or more compounds represented by chemical formula II. Specifically, the host material includes a first host material and a second host material. The first host material includes one or more compounds represented by formula I, and the second host material includes one or more compounds represented by formula II.

[0050] In conjunction with the third aspect, the doped material includes one or more compounds represented by chemical formula III.

[0051] The beneficial effects of this invention are as follows:

[0052] The first aspect of this invention provides an organic electroluminescent compound in which a pyridylcarbazole fragment is attached to an anthracene structure. The anthracene fragment has strong conjugation, enabling it to transport both holes and electrons, while the carbazole group has strong electron-donating ability. By introducing a pyridyl group onto the carbazole and then attaching the pyridylcarbazole fragment to the anthracene structure, this invention not only enhances the electron-donating ability of the compound and regulates the electron mobility of the molecule, but also makes the film formation of the material more stable and improves the lifetime of the organic electroluminescent device.

[0053] A second aspect of this invention provides a composition comprising the compound of Formula I described in the first aspect, a compound of Formula II containing a furan structure, and a compound of Formula III containing a steric hindrance and a thiophene structure. The compound of Formula I provided by this invention contains a pyridylcarbazole structure, which has electron-donating properties and can adjust the electron cloud density on the anthracene ring, facilitating hole transport. The compound of Formula II provided by this invention contains a furan structure, which has electron-withdrawing properties and can adjust the electron cloud density on the anthracene ring, facilitating electron transport. Compared to fused-ring anthracene compounds, the mixture formed by the interaction of the compound of Formula I and the compound of Formula II in this invention is more suitable for electron and hole transport and can significantly balance carrier transport. The composition provided by this invention, by defining the structures of the compounds of Formula I, Formula II, and Formula III respectively, allows the molecules of the compound of Formula III in the composition to be horizontally distributed in the mixture composed of the compounds of Formula I and Formula II through the interaction of the compound of Formula III with the compounds of Formula I and Formula II. This makes the light emitted by the compound of Formula III more inclined to be emitted in a direction perpendicular to the substrate, thereby reducing energy loss during light transmission.

[0054] A third aspect of this invention provides an organic electroluminescent device, comprising a compound of Formula I as a first host compound, a compound of Formula II as a second host compound, a mixture of the compounds of Formula I and Formula II as a host material, and a compound of Formula III as a dopant material applied to the luminescent layer of the organic electroluminescent device. Compared to traditional blue light host materials, the mixture of the compounds of Formula I and Formula II formed by the interaction of these two compounds is more suitable for electron and hole transport, significantly improving the carrier balance of the blue light host material. This ensures that the recombination center is located in the center of the luminescent layer, avoiding energy loss caused by recombination center deviation and reducing the risk of decomposition of adjacent layers, thereby improving the efficiency and lifetime of the organic electroluminescent device. Furthermore, by introducing a pyridine fragment into the carbazole group of the first host compound, the pyridine can form hydrogen bonds with the molecules of the second host compound and the dopant material, making the film formation more stable and thus improving the luminescence lifetime of the organic electroluminescent device. The composition provided by this invention, through the interaction of the first host compound and the compound of Formula II, further enhances the luminescence lifetime of the organic electroluminescent device. The structure of the compound, the second host compound, and the dopant is defined. Through the interaction between the dopant and the first and second host compounds, the molecules of the dopant in the composition are horizontally distributed in the mixture of the first and second host compounds. This causes the light emitted by the dopant to tend to be emitted in a direction perpendicular to the substrate, thereby reducing energy loss during light transmission in the organic light-emitting device (OLED) and improving its efficiency. This invention, through the rational combination of host and dopant materials and the interaction between the first and second host compounds and the dopant compound, enables the OLED to exhibit significant advantages of high efficiency and long lifespan. Using the compounds shown in Formula I, Formula II, and Formula III provided by this invention as light-emitting layer materials can improve the luminous efficiency and extend the lifespan of blue OLEDs, overcoming the shortcomings of existing technologies. Attached image description:

[0055] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0056] Figure 1 A schematic diagram of the structure of an organic electroluminescent device containing the compounds and compositions of the present invention;

[0057] Figure description: 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-light-emitting auxiliary layer, 6-light-emitting layer, 7-electron transport layer, 8-electron injection layer, 9-cathode. Detailed Implementation

[0058] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. Those skilled in the art should understand that the specific description below is illustrative rather than restrictive and should not be construed as limiting the scope of protection of the present invention. The embodiments and comparative examples in this specification are provided to provide a more complete explanation of the specification to those skilled in the art. Various modifications can be made based on the embodiments and comparative examples in this specification, and the scope of protection of the present invention should not be limited to the embodiments and comparative examples detailed below.

[0059] The organic compounds and compositions of the present invention are suitable for use in light-emitting elements, display panels, and electronic devices, particularly organic electroluminescent devices. The electronic devices of the present invention are devices comprising a layer of at least one organic compound, and may also comprise layers of inorganic materials or layers formed entirely of inorganic materials. Preferred electronic devices include organic electroluminescent devices (OLEDs), organic integrated circuits (O-ICs), organic field-effect transistors (O-FETs), organic thin-film transistors (O-TFTs), organic light-emitting transistors (O-LETs), organic solar cells (O-SCs), organic dye-sensitized solar cells (O-DSSCs), organic optical detectors, organic photosensors, organic field quenching devices (O-FQDs), light-emitting electrochemical cells (LECs), organic laser diodes (O-lasers), and organic plasma emitting devices. Organic electroluminescent devices (OLEDs) are particularly preferred.

[0060] To better understand the content of this invention, the organic compound, the preparation method of the compound, and the luminescent properties of the device will be explained in detail with reference to embodiments. Various chemical reactions can be applied to the synthesis method of the compound according to one embodiment of this invention. However, it should be noted that the synthesis method of the compound according to one embodiment of this invention is not limited to the synthesis method described below. Unless otherwise stated, subsequent synthesis is carried out in an anhydrous solvent under a protective gas atmosphere. Solvents and reagents can be purchased from conventional reagent suppliers.

[0061] Compound Synthesis Examples

[0062] Synthesis of intermediates of the first main compound

[0063]

[0064] K-1 (24.6 g, 0.1 mol), L-1 (9.7 g, 0.1 mol), and potassium hydroxide (5.6 g, 0.1 mol) were added to 500 mL of dimethylformamide. The mixture was heated to 80 °C and stirred for 6 hours. After cooling to room temperature, 1000 mL of water was added to the reaction system, and the mixture was filtered to obtain a solid. The solid was then filtered again to obtain a filter cake. The filter cake was recrystallized twice with a mixed solution of toluene and ethanol (volume ratio of toluene to ethanol was 1:3) to obtain Sub-5 (24.7 g, 0.077 mol), with a yield of 76.7% and MS (m / z) (M+): 322.2.

[0065] Sub-5 (24.7 g, 0.077 mol) was dissolved in 250 mL of tetrahydrofuran, cooled to -78 °C, stirred, and 31 mL of n-butyllithium (2.5 mol / L) was added to the reaction system. The mixture was stirred at -78 °C for 1 hour, and then trimethyl borate (8.32 g, 0.08 mol) was added and stirred for 30 minutes. The reaction system was heated to 0 °C, and 100 mL of 1 mol / L hydrochloric acid was added. The mixture was heated to room temperature and stirred for 1 hour. 500 mL of toluene and 500 mL of water were added to the reaction system, and the mixture was separated to obtain the organic phase. The organic phase was evaporated to dryness to obtain the crude product. The crude product was purified by column chromatography (the mobile phase was petroleum ether / ethyl acetate at a volume ratio of 1:1) to obtain product B9 (16.6 g, 0.058 mol), with a yield of 75.3% and MS (m / z) (M+): 287.1.

[0066] After obtaining B9 through the above process, other first host compound intermediates can be prepared using a method similar to that used for B9.

[0067] Example 1

[0068] This embodiment provides a first host compound C9, the synthetic route of which is as follows:

[0069]

[0070] A9 (3.83 g, 10 mmol) and B9 (2.87 g, 10 mmol) were added to 100 mL of a toluene-water mixture (toluene to water volume ratio 4:1). Under nitrogen protection, potassium carbonate (1.65 g, 10 mmol) and 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride (73 mg, 0.1 mmol) were added. The reaction system was heated to reflux and maintained for 16 hours. After cooling to room temperature, the reaction was quenched with ice water. The organic phase was separated and dried over anhydrous magnesium sulfate after filtration. The solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography to finally obtain product C9: 3.00 g (yield: 55%), MS (m / z) (M+): 546.7.

[0071] Example 2

[0072] This embodiment provides a first host compound C10, the synthetic route of which is as follows:

[0073]

[0074] Using the same method as in Example 1, A10 (4.59 g, 10 mmol) was replaced with A9, and B10 (2.87 g, 10 mmol) was replaced with B9, finally yielding product C10: 3.42 g (yield: 55%), MS (m / z) (M+): 622.8.

[0075] Example 3

[0076] This embodiment provides a first host compound C11, the synthetic route of which is as follows:

[0077]

[0078] Using the same method as in Example 1, A11 (3.83 g, 10 mmol) was replaced with A9, and B11 (3.37 g, 10 mmol) was replaced with B9, finally yielding product C11: 3.34 g (yield: 56%), MS (m / z) (M+): 596.7.

[0079] Example 4

[0080] This embodiment provides a first host compound C12, the synthetic route of which is as follows:

[0081]

[0082] Using the same method as in Example 1, A12 (3.83 g, 10 mmol) was replaced with A9, and B12 (3.37 g, 10 mmol) was replaced with B9, finally yielding product C12: 4.05 g (yield: 68%), MS (m / z) (M+): 596.7.

[0083] Example 5

[0084] This embodiment provides a first host compound C13, the synthetic route of which is as follows:

[0085]

[0086] Using the same method as in Example 1, A13 (3.83 g, 10 mmol) was replaced with A9, and B13 (3.37 g, 10 mmol) was replaced with B9, finally yielding product C13: 3.69 g (yield: 62%), MS (m / z) (M+): 596.7.

[0087] Example 6

[0088] This embodiment provides a first host compound C14, the synthetic route of which is as follows:

[0089]

[0090] Using the same method as in Example 1, A14 (3.83 g, 10 mmol) was replaced with A9, and B14 (4.13 g, 10 mmol) was replaced with B9, finally yielding product C14: 3.56 g (yield: 53%), MS (m / z) (M+): 672.8.

[0091] Example 7

[0092] This embodiment provides a second host compound C1, the synthetic route of which is as follows:

[0093]

[0094] A1 (3.83 g, 10 mmol) and B1 (2.12 g, 10 mmol) were added to 100 mL of a toluene-water mixture (toluene to water volume ratio 4:1). Under nitrogen protection, potassium carbonate (1.65 g, 10 mmol) and 1,1'-bis(diphenylphosphine)ferrocene palladium dichloride (73 mg, 0.1 mmol) were added. The reaction system was heated to reflux and maintained for 16 hours. After cooling to room temperature, the reaction was quenched with ice water. The organic phase was separated and filtered. The organic phase was dried over anhydrous magnesium sulfate and the solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography to finally obtain product C1: 3.05 g (yield: 65%), MS (m / z) (M+): 470.6.

[0095] Example 8

[0096] This embodiment provides a second host compound C2, the synthetic route of which is as follows:

[0097]

[0098] Using the same method as in Example 7, except that A2 (4.59 g, 10 mmol) replaced A1 and B2 (2.12 g, 10 mmol) replaced B1, the final product C2 was obtained: 4.10 g (yield: 75%), MS (m / z) (M+): 546.7.

[0099] Example 9

[0100] This embodiment provides a second host compound C3, the synthetic route of which is as follows:

[0101]

[0102] Using the same method as in Example 7, except that A3 (4.59 g, 10 mmol) replaced A1 and B3 (2.62 g, 10 mmol) replaced B1, the final product C3 was obtained: 3.16 g (yield: 53%), MS (m / z) (M+): 596.7.

[0103] Example 10

[0104] This embodiment provides a second host compound C4, the synthetic route of which is as follows:

[0105]

[0106] Using the same method as in Example 7, except that A4 (4.59 g, 10 mmol) replaced A1 and B4 (2.62 g, 10 mmol) replaced B1, the final product C4 was obtained: 3.10 g (yield: 52%), MS (m / z) (M+): 596.7.

[0107] Example 11

[0108] This embodiment provides a second host compound C5, the synthetic route of which is as follows:

[0109]

[0110] Using the same method as in Example 7, except that A5 (3.83 g, 10 mmol) replaced A1 and B5 (2.62 g, 10 mmol) replaced B1, the final product C5 was obtained: 4.27 g (yield: 82%), MS (m / z) (M+): 520.6.

[0111] Example 12

[0112] This embodiment provides a second host compound C6, the synthetic route of which is as follows:

[0113]

[0114] Using the same method as in Example 7, except that A6 (3.83 g, 10 mmol) replaced A1 and B6 (2.88 g, 10 mmol) replaced B1, the final product C6 was obtained: 3.01 g (yield: 55%), MS (m / z) (M+): 546.7.

[0115] Example 13

[0116] This embodiment provides a second host compound C7, the synthetic route of which is as follows:

[0117]

[0118] Using the same method as in Example 7, except that A7 (4.67 g, 10 mmol) replaced A1 and B7 (2.88 g, 10 mmol) replaced B1, the final product C7 was obtained: 4.60 g (yield: 73%), MS (m / z) (M+): 630.8.

[0119] Example 14

[0120] This embodiment provides a second host compound C8, the synthetic route of which is as follows:

[0121]

[0122] Using the same method as in Example 7, except that A8 (3.83 g, 10 mmol) replaced A1 and B8 (2.62 g, 10 mmol) replaced B1, the final product C8 was obtained: 3.59 g (yield: 69%), MS (m / z) (M+): 520.6.

[0123] Synthesis of intermediates for doped materials

[0124]

[0125] The general formula for intermediate synthesis is shown above. The target intermediate can be obtained through a two-step Buchwald-Hartwig coupling synthesis method.

[0126] Specific examples are as follows:

[0127]

[0128] F-1 (8.75 g, 0.05 mol), G-1 (12.11 g, 0.045 mol), and sodium tert-butoxide (5.28 g, 0.055 mol) were added to toluene (200 mL). Then, under nitrogen protection, palladium dibenzylacetone (0.46 g, 0.5 mmol) and SPhos (0.41 g, 1 mmol) were introduced. The reaction system was then heated to 110 °C, refluxed, and maintained for 8 hours. After cooling to room temperature, the reaction was quenched with water and separated to obtain the organic phase. The organic phase was filtered and dried over anhydrous magnesium sulfate. The solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography to obtain product Sub1: 11.47 g, yield: 70%, MS (m / z) (M+): 364.

[0129]

[0130] H-1 (16.9 g, 0.05 mol), J-1 (15.26 g, 0.045 mol), and sodium tert-butoxide (5.28 g, 0.055 mol) were added to toluene (500 mL). Under nitrogen protection, palladium dibenzylacetone (0.46 g, 0.5 mmol) and SPhos (0.41 g, 1 mmol) were introduced. The reaction system was then heated to 110 °C, refluxed, and maintained for 8 hours. After cooling to room temperature, the reaction was quenched with water and separated to obtain the organic phase. The organic phase was filtered and dried with anhydrous sodium sulfate. The solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography to obtain product Sub4: 20.01 g, yield: 81%, MS (m / z) (M+): 549.

[0131]

[0132] Sub1 (3.64 g, 10 mmol), Sub2 (2.63 g, 9 mmol), and sodium tert-butoxide (1.05 g, 11 mmol) were added to toluene (50 ml). Under nitrogen protection, bis(dibenzylacetone)palladium (274.28 mg, 0.30 mmol) and tri-tert-butylphosphine (121.2 mg, 0.6 mmol) were introduced. The reaction system was then heated to reflux and maintained for 10 hours. After cooling to room temperature, the reaction was quenched with water and separated to obtain the organic phase. The organic phase was filtered and dried over anhydrous sodium sulfate. The solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography to finally obtain product Sub3: 4.14 g (yield: 80%), MS (m / z) (M+): 575.

[0133] Sub3 (5.75 g, 10 mmol), Sub4 (5.49 g, 10 mmol), and sodium tert-butoxide (1.05 g, 11 mmol) were added to toluene (100 ml). Under nitrogen protection, bis(dibenzylacetone)palladium (274.28 mg, 0.30 mmol) and tri-tert-butylphosphine (121.2 mg, 0.6 mmol) were introduced. The reaction system was then heated to reflux and maintained for 10 hours. After cooling to room temperature, the reaction was quenched with water and separated to obtain the organic phase. The organic phase was filtered and dried with anhydrous sodium sulfate. The solvent was removed by rotary evaporation to obtain the crude product. The crude product was purified by column chromatography to finally obtain product D1: 6.77 g (yield: 65%), MS (m / z) (M+): 1042.

[0134] After obtaining D1 through the above process, other doped material intermediates can be prepared using a method similar to that of D1.

[0135] Example 15

[0136] This embodiment provides a compound E1 as a dopant material. The synthetic route of this compound is as follows:

[0137]

[0138] D1 (10.42 g, 10 mmol) was added to tert-butylbenzene (125 mL), and then the mixture was cooled to 0 °C under nitrogen protection. 12.4 mL (21 mmol) of 1.7 M tert-butyllithium pentane solution was added, and the mixture was heated to 60 °C and stirred for 2 hours. The mixture was then cooled to 0 °C, and 2.0 mL (21 mmol) of boron tribromide was added and stirred for 0.5 h. Then, 3.65 mL (21 mmol) of N,N-diisopropylethylamine was added at 0 °C, and the mixture was heated to 60 °C and stirred for 2 h. After cooling to room temperature, the reaction was quenched with ice water and separated to obtain the organic phase. The organic phase was filtered and dehydrated with anhydrous magnesium sulfate. After removing the organic solvent by rotary evaporation, the crude product was obtained. The crude product was purified by recrystallization from dichloromethane and n-heptane to finally obtain product E1: 1.46 g (yield: 15%), MS (m / z) (M+): 971.

[0139] Example 16

[0140] This embodiment provides a compound E2 as a dopant material, and the synthetic route of this compound is as follows:

[0141]

[0142] Using the same method as in Example 15, except that D2 (12.51 g; 10 mmol) was used instead of D1, the final product E2 was obtained: 0.87 g (yield: 73.8%), MS (m / z) (M+): 1179.6.

[0143] Example 17

[0144] This embodiment provides a compound E3 as a dopant material, and the synthetic route of this compound is as follows:

[0145]

[0146] Using the same method as in Example 15, except that D3 (9.72 g; 10 mmol) was used instead of D1, the final product E3 was obtained: 0.34 g (yield: 37.2%), MS (m / z) (M+): 901.2.

[0147] Example 18

[0148] This embodiment provides a compound E4 as a dopant material, and the synthetic route of this compound is as follows:

[0149]

[0150] Using the same method as in Example 15, except that D4 (11.09 g; 10 mmol) was used instead of D1, the final product E4 was obtained: 0.72 g (yield: 6.9%), MS (m / z) (M+): 1037.4.

[0151] Example 19

[0152] This embodiment provides a compound E5 as a dopant material, and the synthetic route of this compound is as follows:

[0153]

[0154] Using the same method as in Example 15, except that D5 (10.56 g; 10 mmol) was replaced with D1, the final product E5 was obtained: 0.53 g (yield: 5.41%), MS (m / z) (M+): 985.3.

[0155] Example 20

[0156] This embodiment provides a compound E6 as a dopant material, and the synthetic route of this compound is as follows:

[0157]

[0158] Using the same method as in Example 15, except that D6 (11.19 g; 10 mmol) was used instead of D1, the final product E6 was obtained: 0.69 g (yield: 6.56%), MS (m / z) (M+): 1047.4.

[0159] Example 21

[0160] This embodiment provides a compound E7 as a dopant material, and the synthetic route of this compound is as follows:

[0161]

[0162] Using the same method as in Example 15, except that D7 (11.51 g; 10 mmol) was used instead of D1, the final product E7 was obtained: 0.83 g (yield: 7.65%), MS (m / z) (M+): 1079.5.

[0163] Example 22

[0164] This embodiment provides a compound E8 as a dopant material, and the synthetic route of this compound is as follows:

[0165]

[0166] Using the same method as in Example 15, except that D8 (10.95 g; 10 mmol) was used instead of D1, the final product E8 was obtained: 0.38 g (yield: 3.73%), MS (m / z) (M+): 1023.4.

[0167] Example 23

[0168] This embodiment provides a compound E9 as a dopant material, and the synthetic route of this compound is as follows:

[0169]

[0170] Using the same method as in Example 15, except that D9 (10.97 g; 10 mmol) was replaced with D1, the final product E9 was obtained: 0.32 g (yield: 3.15%), MS (m / z) (M+): 1025.4.

[0171] Example 24

[0172] This embodiment provides a compound E10 as a dopant material, and the synthetic route of this compound is as follows:

[0173]

[0174] Using the same method as in Example 15, except that D10 (9.56 g; 10 mmol) was replaced with D1, the final product E10 was obtained: 0.58 g (yield: 6.51%), MS (m / z) (M+): 885.1.

[0175] Composition Examples

[0176] Examples 25 to 112

[0177] The first host compound, the second host compound, and the compound used as a dopant are combined according to Table 1 and mixed evenly to obtain compositions T1 to T88, wherein the mass ratio of the first host compound, the second host compound, and the compound used as a dopant is 49:49:2.

[0178] Table 1

[0179]

[0180]

[0181] Comparative Example 1

[0182] This comparative example provides a compound DBH1 that was tested during the research process, and its specific structural formula is as follows:

[0183]

[0184] Comparative Example 2

[0185] This comparative example provides a compound DBH2 that was tested during the research process, and its specific structural formula is as follows:

[0186]

[0187] Comparative Example 3

[0188] This comparative example provides a compound BD-1 that was tested during the research process, and its specific structural formula is as follows:

[0189]

[0190] Comparative Example 4

[0191] This comparative example provides a compound BD-2 that was tested during the research process, and its specific structural formula is as follows:

[0192]

[0193] Comparative Examples of Compositions

[0194] Comparative examples 5 to 10

[0195] The first host compound, the second host compound, and the compound used as a dopant are combined according to Table 2 and mixed evenly to obtain compositions DT1 to DT6. The mass ratio of the first host compound, the second host compound, and the compound used as a dopant in DT1 to DT4 is 49:49:2, and the mass ratio of the host compound and the compound used as a dopant in DT5 to DT6 is 98:2.

[0196] Table 2

[0197] Comparative Example Composition First main compound Second main compound Doped materials 5 DT1 C11 DBH2 E10 6 DT2 DBH1 C4 E10 7 DT3 C11 C4 DBD1 8 DT4 C11 C4 DBD2 9 DT5 C11 -- E10 10 DT6 -- C4 E10

[0198] Composition performance evaluation

[0199] (1) In order to demonstrate that the mixed host material composed of the first host compound and the second host compound in the composition provided by the present invention can balance the carrier transport, the hole mobility μh and electron mobility μe of the mixture composed of the first host compound and the second host compound are calculated respectively, and then μe / μh is calculated. The closer the value of μe / μh is to 1, the more balanced the carrier transport is in the mixture composed of the first host compound and the second host compound.

[0200] The Time-of-Flight (TOF) method is currently the most effective method for measuring carrier mobility in organic semiconductor materials. It can test the relatively low mobilities of small organic molecules and polymers that can be fabricated into thin films, as well as the low mobilities of crystalline materials. The TOF experiment utilizes the photoconductivity of organic semiconductor materials. It measures the time it takes for photogenerated carriers to travel through the sample under an applied electric field, and then calculates the carrier mobility based on the relationship between the mobility, the external electric field, and the carrier drift velocity. With an applied deflection voltage of V, a hole transit time of t, and a film thickness of d, the mobility μ can be expressed as: μ = d 2 / Vt;

[0201] Specific experimental steps: ① Mix the first main compound provided in Examples 1 to 6 and Comparative Example 1 with the second main compound provided in Examples 7 to 14 and Comparative Example 2 according to Table 3. The mass ratio of the first main compound to the second main compound is 1:1 to obtain a mixture.

[0202] ② The mixture was deposited onto ITO to form a 1000 nm thin film, and then Al was deposited onto the thin film to form a cathode with a thickness of 150 nm to prepare the sample to be tested.

[0203] ③ Apply a 20V deflection voltage to the sample to be tested. Measure the time it takes for photogenerated carriers to travel through the sample under the applied electric field. Calculate the hole mobility μh and electron mobility μe of the material, and then calculate μe / μh. The specific calculation results are shown in Table 3.

[0204] Table 3

[0205]

[0206]

[0207] As can be seen from the data in Table 3, the μe / μh value of the mixed host material composed of the first host compound and the second host compound provided by the present invention is closer to 1. If either the first host compound or the second host compound in the mixed host material provided by the present invention is replaced with other commonly used compounds of the same type, the μe / μh value will deviate significantly from 1, indicating that the mixed host material provided by the present invention can effectively balance carrier transport. The composition provided by this invention includes a first host compound containing a pyridylcarbazole structure and a second host compound containing a dibenzofuran structure. As shown in Table 3, the μe / μh value of the mixture composed of C13 and C5 provided by this application is significantly greater than the μe / μh value of the mixture composed of DBH1 and C5 in the comparative example, and is closer to 1. By introducing a pyridyl group onto a carbazole and then linking the pyridylcarbazole fragment to an anthracene fragment, this invention can not only enhance the electron-donating ability of the compound and regulate the electron mobility of the molecule, but also, compared with the anthracene compound (DBH1) containing only a carbazole group, the mixture formed by mixing the compound containing the pyridylcarbazole structure and the compound containing the furan structure provided by this invention is more suitable for electron and hole transport and can significantly balance carrier transport.

[0208] (2) To demonstrate that the composition provided by the present invention is more conducive to the horizontal distribution of dopant materials in the host material, the alignment factor of the composition provided by the present invention was tested using the Hamamatsu C14234-11 molecular orientation characteristic measurement system. When the alignment factor is equal to 0.67, it indicates that the dopant materials exhibit isotropic distribution in the host material, and when the alignment factor is equal to 1, it indicates that the dopant materials are all horizontally distributed.

[0209] In organic electroluminescent devices, the closer the alignment factor is to 1, the better the horizontal distribution of the molecules of the dopant material in the host material. The light emitted by the dopant material tends to be emitted in a direction perpendicular to the substrate. Increasing the probability of the light emitted by the dopant material being emitted in a direction perpendicular to the substrate can reduce the energy loss caused by light transmission in organic electroluminescent devices.

[0210] The alignment factors of the compositions provided in Examples 25 to 112 and Comparative Examples 5 to 10 were tested using the Hamamatsu C14234-11 molecular orientation characteristic measurement system.

[0211] Specific experimental steps: ① The composition was vapor-deposited onto a quartz substrate; ② The system excited the sample under test using an LED light source, and the sample emitted light. The p-polarized light in the emitted light was detected by a polarizer and received by a detector; ③ The alignment factor was read by the instrument. The specific results are shown in Table 4.

[0212] Table 4

[0213]

[0214]

[0215] As shown in Table 4, compared with the comparative composition, the alignment factor of the composition provided by the present invention is closer to 1. Replacing any one of the dopant compound, the first host compound, or the second host compound in the composition T1 provided by the present invention with other commonly used compounds of the same type, or removing them, significantly deviates the alignment factor from 1. This indicates that the dopant material provided by the present invention is well aligned with the mixed host material provided by the present invention, and the molecules of the dopant material provided by the present invention can be horizontally distributed in the mixed host material provided by the present invention. The test results show that the alignment factor of the composition is affected not only by the structure of the dopant material but also by the structure of the host material. The composition provided by the present invention, by defining the structures of the dopant material, the first host compound, and the second host compound respectively, allows the molecules of the dopant material in the composition to be horizontally distributed in the mixed host composed of the first host compound and the second host compound through the interaction between the dopant material and the first host compound and the second host compound. This makes the light emitted by the dopant material more inclined to be emitted in a direction perpendicular to the substrate, thereby reducing the energy loss caused by light transmission in the organic electroluminescent device.

[0216] Device Example 1

[0217] This embodiment provides a blue organic light-emitting diode (OLED), the fabrication method of which is as follows: First, a hole injection layer is formed on an ITO layer (anode) formed on a substrate by vacuum deposition of HTL and p-dopant (HTL to p-dopant mass ratio of 97:3) with a thickness of 10 nm; second, a hole transport layer is formed on the hole injection layer by vacuum deposition of HTL with a thickness of 120 nm; and third, a B2O3 layer is formed on the hole transport layer by vacuum deposition with a thickness of 5 nm. A light-emitting auxiliary layer is formed by vacuum deposition of a mixture of host material and dopant material on the aforementioned light-emitting auxiliary layer. The host material consists of C11 and C4, with C11 as the first host compound and C4 as the second host compound. E10 is used as the dopant material, with a mass ratio of 49:49:2. Next, a hole-blocking layer (HBL) is vacuum-deposited on the aforementioned light-emitting layer to a thickness of 5 nm. An electron transport layer is formed by vacuum deposition of a mixture of ET and Liq (with a mass ratio of 1:1) to a thickness of 30 nm. Then, an electron injection layer is formed by depositing LiF to a thickness of 0.2 nm on the aforementioned electron transport layer. Finally, an electron cathode is formed by depositing aluminum (Al) to a thickness of 150 nm on the aforementioned electron injection layer, thus fabricating a blue organic light-emitting device.

[0218] Apart from the host material and doped material of the light-emitting layer, the molecular structure formulas of the other layers are as follows:

[0219]

[0220] The electrode preparation method and the deposition method of each functional layer in this embodiment are conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, and will not be described in detail here.

[0221] Device Example 2-100

[0222] The method is the same as in Device Example 1, except that the first host compound, the second host compound, and the dopant material are combined according to Table 5.

[0223] Table 5 Comparison of main materials and doped materials in device embodiments

[0224]

[0225]

[0226]

[0227] Device Comparison Examples 1-6

[0228] The method is the same as in Device Example 1, except that the light-emitting layer material is replaced with the composition of Comparative Examples 5 to 10. The main material and doped material in the device examples are shown in Table 6.

[0229] Table 6 Comparison of main materials and doped materials in the device comparison examples.

[0230] Device Comparison First main compound Second main compound Doped materials Device Comparison Example 1 C11 DBH2 E10 Device Comparison Example 2 DBH1 C4 E10 Device Comparison Example 3 C11 C4 DBD1 Device Comparison Example 4 C11 C4 DBD2 Device Comparison Example 5 C11 -- E10 Device Comparison Example 6 -- C4 E10

[0231] Example of device performance

[0232] The organic electroluminescent devices provided in Device Examples 1-100 and Comparative Examples 1-6 were tested using standard methods. For this purpose, J = 10 mA / cm² was used. 2 The driving voltage, luminance, electroluminescent current efficiency (in cd / A), and external quantum efficiency (EQE, in percentage) of the organic electroluminescent device were determined as a function of luminescence density from the current / voltage / luminescence density characteristic line (IVL characteristic line) exhibiting Lambertian emission characteristics, and the emission spectrum. The lifetime LT was defined as the time after which, when operating at a constant current J, the luminance decreased from the initial luminance L0 to a specific proportion L1; J = 50 mA / cm². 2 The statement L1 = 90% refers to a value of 50 mA / cm. 2When operating below the threshold, the luminous intensity decreases to 90% of its initial value L0 after time LT. Similarly, J = 20 mA / cm² 2 L1 = 80% means that at 20 mA / cm 2 When operating below the threshold, the luminous intensity drops to 80% of its initial value L0 after time LT.

[0233] The testing instruments and methods used to perform performance testing on the above-mentioned OLED devices are as follows:

[0234] Brightness was tested using a PhotoResearch PR-635 spectral scanner;

[0235] Current density and turn-on voltage: tested using a Keithley 2400 digital source meter;

[0236] Life test: The LT-96ch life test device was used.

[0237] The performance test results of the above devices are listed in Table 7.

[0238] Table 7 Performance test results of blue light devices

[0239]

[0240]

[0241]

[0242] As shown in Table 7 above, the device performance test results indicate that, compared with the comparative device, the organic electroluminescent device provided by this invention exhibits significantly improved efficiency and lifetime. Replacing any one of the doping material, the first host compound, or the second host compound in the organic electroluminescent device provided by this invention with other commonly used compounds of the same type, or removing them altogether, significantly reduces both efficiency and lifetime. This is because the first host compound provided by this invention, by introducing a pyridinium group onto a carbazole and then linking the pyridylcarbazole fragment to anthracene fragment, not only enhances the electron-donating ability of the compound and regulates the electron mobility of the molecule, but also, compared to anthracene compounds containing only a carbazole group, the mixed host material composed of the first and second host compounds provided by this invention is more suitable for electron and hole transport. This significantly improves the carrier balance of the blue light host material, ensuring the recombination center is located in the center of the luminescent layer, thus avoiding energy loss due to recombination center deviation. This invention reduces energy loss and the risk of adjacent layer material decomposition, thereby improving the efficiency and lifetime of organic light-emitting devices (OLEDs). By introducing a pyridine fragment into the carbazole group in the first host compound, pyridine can form hydrogen bonds with molecules of the second host compound and the dopant, making the film formation more stable and thus improving the luminescence lifetime of the OLED. The composition provided by this invention defines the structures of the dopant, the first host compound, and the second host compound respectively. Through the interaction between the dopant and the first and second host compounds, the molecules of the dopant in the composition are horizontally distributed in the mixed host composed of the first and second host compounds. This makes the light emitted by the dopant more inclined to be emitted in a direction perpendicular to the substrate, thereby reducing energy loss during light transmission in the OLED and improving its efficiency. This invention, through the rational combination of dual host materials and dopant, and the interaction between the first host compound, the second host compound, and the compound serving as the dopant, enables the OLED to exhibit significant advantages of high efficiency and long lifetime. Using the composition provided by this invention as the light-emitting layer material can improve the luminous efficiency of blue organic electroluminescent devices and extend their lifespan, overcoming the shortcomings of the prior art.

[0243] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A composition, characterized in that, The composition comprises one or more compounds of formula I, and the composition further comprises one or more compounds of formula II and one or more compounds of formula III; The compound represented by Formula I is selected from the following structures: ； The compound represented by Formula II is selected from the following structures: ； The compound represented by Formula III is selected from the following structures: 。 2. An organic electroluminescent device, characterized in that, Includes a first electrode sequentially disposed on a substrate, configured to be connected to the first electrode. A second electrode opposite to the first electrode, and one or more organic functional layers disposed between the first electrode and the second electrode; The organic functional layer includes a light-emitting layer, which comprises the composition of claim 1.

3. The organic electroluminescent device according to claim 2, characterized in that, The light-emitting layer includes a host material and a dopant material. The host material includes one or more compounds represented by chemical formula I and one or more compounds represented by chemical formula II. The dopant material includes one or more compounds represented by chemical formula III.

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