Blue light host material, preparation method and organic electroluminescent device

Abstract

The invention belongs to the field of organic electroluminescent materials, and discloses a blue light host material, a preparation method and an organic electroluminescent device. The structure of the blue light host material is as shown in a chemical formula I: # imgabs0 #. After the blue light host material provided by the invention is applied to the organic electroluminescent device, the driving voltage of the photoelectric device can be reduced, the luminous efficiency of the photoelectric device can be improved, and the service life of the photoelectric device can be prolonged.

Description

Technical Field

[0001] The invention belongs to the field of organic electroluminescent materials, and in particular relates to a blue light main body material, a preparation method and an organic electroluminescent device. Background Art

[0002] As the first generation of OLED light-emitting materials, fluorescent materials have the advantages of good stability and high color purity. Since fluorescent materials only use singlet excitons, while triplet excitons are seriously wasted, the performance of electroluminescent devices based on fluorescent materials is relatively low. However, since the color purity and stability of blue fluorescent materials are much better than those of blue phosphorescent materials and thermally delayed fluorescent materials, and most of the blue light materials in the currently industrialized three-primary color materials use fluorescent materials, the development and application of blue fluorescent materials still attracts the attention of a large number of scientific researchers and enterprises.

[0003] At present, almost all light-emitting layers in blue organic electroluminescent devices use a host-guest doped light-emitting system, that is, electroluminescence is achieved by doping the host material with the guest doping material. The host material in the device must have good film-forming properties, thermal stability, electrochemical properties and carrier transport properties. The following requirements should be met when designing and selecting the host material: (1) The HOMO / LUMO energy level of the host material should cover the HOMO / LUMO of the light-emitting material; (2) The hole mobility and electron mobility of the host material should be as close as possible, so that the exciton recombination area in the device can be effectively confined to the light-emitting layer; (3) The triplet energy level of the host material should be higher than the triplet energy level of the light-emitting material to prevent the energy transfer from the light-emitting material to the host material, causing unnecessary energy loss and affecting the device performance; (4) The HOMO energy level of the host material should match the HOMO energy level of the hole transport material, and the LUMO energy level should match the LUMO energy level of the electron transport material to reduce the energy gap difference of hole or electron injection and reduce the operating voltage of the device.

[0004] The research and development and selection of the main material have a great impact on the performance of the device. The commonly used blue fluorescent devices mainly use anthracene-based main materials. Since the anthracene group has a large planar conjugated structure, it has high fluorescence quantum efficiency, strong carrier mobility and charge injection ability, making it have high commercial application value. However, since it is very easy to form strong π-π stacking between its molecules, the efficiency of the blue light material with good performance is reduced, the emission wavelength is red-shifted, and the color purity is reduced, which limits its application in solid-state luminescence. Therefore, the development of anthracene derivatives cannot be stopped. Summary of the invention

[0005] In view of this, and in view of the deficiencies in the prior art, the present invention discloses a blue light host material, a preparation method and an organic electroluminescent device.

[0006] It should be noted that the present invention provides a compound that can be used as a blue light host material in a light-emitting layer, with a deuterated anthracene group and a rigid benzonaphthofuran group as the main mother core skeleton. The material has good thermal stability and film-forming properties. The introduction of a deuterated aromatic group on the deuterated anthracene group can effectively extend the conjugated system, making it easier to match other functional layers, thereby improving the luminous efficiency of the device and extending its service life.

[0007] In order to achieve the above objectives, the first objective of the present invention is to provide a blue light host material. The following technical scheme is adopted:

[0008] A blue light host material, the blue light material has a general structural formula of Chemical Formula I:

[0009] ;

[0010] in,

[0011] Ar is independently selected from phenyl, and the position of the phenyl ring on the dibenzofuran group is 1, 2, 2, 3 or 3, 4, and the connection position is as follows: ;

[0012] R1 is independently selected from a C6-C30 aryl group fully or partially substituted by deuterium, a C2-C30 heteroaryl group fully or partially substituted by deuterium, or a combination of the above aryl groups and heteroaryl groups, wherein the heteroatom in the heteroaryl group contains at least one of O, S, N, Si, and Se;

[0013] R2 is independently selected from C6-C30 aryl groups fully or partially substituted by deuterium.

[0014] Furthermore, the chemical formula I is preferably the following chemical formula Ⅰ-A to chemical formula Ⅰ-C:

[0015] .

[0016] Further, R1 is independently selected from a C6-C18 aryl group fully or partially substituted by deuterium, a C5-C24 heteroaryl group fully or partially substituted by deuterium, or a combination of the above aryl groups and heteroaryl groups, wherein the heteroatom in the heteroaryl group contains at least one of O, S, N, Si, and Se;

[0017] R2 is independently selected from C6-C18 aryl groups fully or partially substituted by deuterium.

[0018] Furthermore, R1 is independently selected from the following groups or any combination thereof:

[0019] , * indicates a connection point; among them,

[0020] R3-R 15Each is independently selected from deuterium, C1-C6 alkyl partially or fully substituted by deuterium;

[0021] n3、n 10 Each is independently selected from 0, 1, 2, 3, 4, 5;

[0022] n4 and n7 are each independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;

[0023] n5、n 13 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13;

[0024] n6 and n8 are each independently selected from 0, 1, 2, 3, 4, 5, 6, and 7;

[0025] n9、n 15 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8;

[0026] n 11 Independently selected from 0, 1, 2, 3, 4;

[0027] n 12 、n 14 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11.

[0028] Furthermore, R2 is independently selected from the following groups or any combination:

[0029] , * indicates a connection point; among them,

[0030] R 16 -R 24 Each is independently selected from deuterium, C1-C6 alkyl partially or fully substituted by deuterium;

[0031] n 16 Each is independently selected from 0, 1, 2, 3, 4, 5;

[0032] n 17 、n 20 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;

[0033] n 18 、n 23 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13;

[0034] n 19 、n 21 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7;

[0035] n 22 、n 24 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11.

[0036] In the above technical solution, the blue light host material is selected from any one of the following compounds:

[0037] .

[0038] The second object of the present invention is to provide a method for preparing the blue light host material as described above.

[0039] The blue light host material of the present invention can be prepared by a synthetic method known to those skilled in the art, or preferably prepared by the following reaction process.

[0040] ;

[0041] In the above formula, Ar, R1, R2 are as defined in the above chemical formula I, and X represents or .

[0042] In particular, for complex raw materials that have not been disclosed before, classic Suzuki coupling reaction and bromination reaction are used to synthesize and apply them to the present invention.

[0043] Specifically, the preparation method is as follows:

[0044] Step 1 specifically includes the following processes:

[0045] Add raw material A (1.0-1.2eq), raw material B (1.0eq) and potassium carbonate (2.0-4.0eq) to a reaction flask, then add a mixed solution of toluene, ethanol and water (V:V:V =3:1:1), add tetrakis(triphenylphosphine)palladium (0.01-0.03eq) under nitrogen protection, heat to 85°C-95°C, and reflux for reaction for 3-24h; detect the reaction by thin layer chromatography, after the reaction is completed, cool down, filter with diatomaceous earth to remove salt and catalyst, cool the filtrate to room temperature, extract with dichloromethane and water, separate the liquids, retain the organic phase and concentrate, purify by column chromatography with a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8) to obtain intermediate 1;

[0046] Step 2 specifically includes the following processes:

[0047] Add intermediate 1 (1.0 eq), diboronic acid pinacol ester (1.0-2.0 eq) and potassium acetate (2.0-4.0 eq) to a reaction flask, then add 1,4-dioxane, add tri(dibenzylideneacetone)dipalladium (0.02-0.10 eq) and X-Phos (0.1-0.2 eq) under nitrogen protection, heat to 110-120°C, and reflux for 3-24 hours; detect the reaction by thin layer chromatography, after the reaction is completed, cool down, filter with diatomaceous earth to remove salt and catalyst, cool the filtrate to room temperature, extract with dichloromethane and water, separate the liquids, retain the organic phase and concentrate, purify by column chromatography with a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8) to obtain intermediate 2;

[0048] Step 3 specifically includes the following processes:

[0049] Add intermediate 2 (1.0-1.3eq), raw material C (1.0eq) and potassium carbonate (2.0-4.0eq) into a reaction flask, then add a mixed solution of toluene, ethanol and water (V:V:V =3:1:1), add tetrakis(triphenylphosphine)palladium (0.01-0.03eq) under nitrogen protection, raise the temperature to 85°C-95°C, and reflux for reaction for 3-24h; detect the reaction by thin layer chromatography, after the reaction is completed, cool down, filter with diatomaceous earth to remove salt and catalyst, cool the filtrate to room temperature, extract with dichloromethane and water, separate the liquids, retain the organic phase and concentrate, purify by column chromatography with a mixed solution of dichloromethane and petroleum ether (V:V=1:3-1:8) to obtain chemical formula I.

[0050] The third object of the present invention is to provide an organic electroluminescent device, which comprises the blue light host material.

[0051] Specifically, the organic electroluminescent device comprises a first electrode, a second electrode and at least one organic thin film layer arranged between the first electrode and the second electrode; the organic thin film layer comprises the blue light host material as described above.

[0052] Furthermore, the blue light host material is used as a host material of a light-emitting layer of an organic electroluminescent device.

[0053] Compared with the prior art, the present invention provides a blue light host material, a preparation method and an organic electroluminescent device, which have the following excellent effects:

[0054] The compound disclosed in the present invention is used as a blue light host material, the structure is based on deuterated anthracene and benzonaphthofuran groups as the mother core skeleton, and other deuterated functional groups are introduced, and the device has a lower driving voltage, excellent luminous efficiency and service life. Specifically,

[0055] 1) The anthracene group itself has a large conjugated system and a high fluorescence quantum efficiency, especially in the blue light region. Its rigid planar structure reduces the possibility of non-radiative transitions, effectively improves electron mobility, and thus improves the luminous efficiency of blue light. Its lowest unoccupied molecular orbital (LUMO) energy level is low, which is conducive to the injection and transmission of electrons. The structure of the anthracene group is relatively stable and can withstand high temperatures, so that its structure is not easy to change during the evaporation process, thereby improving the service life of its devices. In addition, the anthracene group also has a wide bandgap, which makes it have strong absorption and emission capabilities in the blue light region. Deuteration of the anthracene group can reduce the vibration frequency of the molecule, reduce the thermal motion of the molecule, help improve the thermal stability of the material, lessen the degradation of the material caused by the increase in temperature, and extend the service life of the material. Because D has lower activity than H, the CD bond is more stable than the CH bond in structure, the non-radiative transition of the compound is reduced, and the structure is more stable, which is conducive to improving the life and efficiency of the material after it is used in the device. In addition, a capping group (deuterated aromatic group) is introduced on the anthracene group. The HOMO energy level of the aromatic group is usually higher and the LUMO energy level is usually lower, which makes the energy gap (HOMO-LUMO energy difference) of the aromatic group larger, making it easier to match other functional layers, making the performance of the device better.

[0056] 2) The introduction of rigid benzonaphthofuran groups helps to improve the thermal stability of the material, thereby enhancing the service life of the device. Fragments of oxygen atoms with high electronegativity in the benzonaphthofuran group can effectively improve the luminescence efficiency of blue light devices. Further introduction of a substituent (aryl or heteroaryl) on the benzonaphthofuran group can effectively extend the conjugated system and enhance the conjugation effect. While improving the fluorescence quantum efficiency, it can also avoid the localization of carrier migration and increase the migration rate, thereby reducing the voltage and improving the luminescence efficiency of the device.

[0057] 3) The 1-position of the benzonaphthofuran group is connected to a deuterated anthracene group, and the 4-position is connected to a deuterated aryl or heteroaryl group, which are the two farthest sites in the benzonaphthofuran group. They can not only effectively reduce the quenching phenomenon caused by aggregation, but also form a more effective conjugated system, enhance the charge transfer and energy transfer within the molecule, which helps to improve the fluorescence quantum efficiency of the material and thus improve the luminescence efficiency of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0059] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of compound 1 provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the related drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] The invention specifically discloses a blue light main body material, a preparation method and an organic electroluminescent device.

[0062] It should be noted that the numerical values ​​given in the following examples are as accurate as possible, but those skilled in the art understand that due to unavoidable measurement errors and experimental operation problems, each number should be understood as an approximate number rather than an absolutely accurate value.

[0063] The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0064] Example 1

[0065] ;

[0066] Step 1 specifically includes the following processes:

[0067] Raw material A-1 (1.2 eq, CAS number: 2660005-47-8), raw material B-1 (1.0 eq, CAS number: 215527-70-1) and potassium carbonate (3.0 eq) were added to a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and tetrakis(triphenylphosphine)palladium (0.02 eq) was added under nitrogen protection. The temperature was raised to 95°C and refluxed for 4 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered and filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation. The organic phase was retained and concentrated, and intermediate 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) to obtain intermediate 1 (yield: 77.7%).

[0068] Step 2 specifically includes the following processes:

[0069] Intermediate 1 (1.0 eq), pinacol diboron (1.3 eq) and potassium acetate (3.0 eq) were added to a reaction flask, followed by 1,4-dioxane, and tri(dibenzylideneacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added under nitrogen protection. The temperature was raised to 120°C and refluxed for 18 h. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered and filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation. The organic phase was retained and concentrated. The intermediate 2 (yield: 75.4%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) to obtain the intermediate 2 (yield: 75.4%).

[0070] Step 3 specifically includes the following processes:

[0071] Intermediate 2 (1.0 eq), raw material C-1 (1.0 eq, CAS number: 2377545-68-9) and potassium carbonate (3.0 eq) were added to a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and tetrakis(triphenylphosphine)palladium (0.03 eq) was added under nitrogen protection. The temperature was raised to 95°C and refluxed for 10 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered and filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation. The organic phase was retained and concentrated, and compound 1 (yield: 82.2%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:5).

[0072] The obtained compound 1 was tested and analyzed, and the results were as follows:

[0073] HPLC purity: >99.8%.

[0074] Mass spectrometry test: The model is Waters XEVO TQD mass spectrometer, using ESI source.

[0075] Test value (ESI, m / Z): [M+H] + ):564.55.

[0076] Elemental Analysis:

[0077] Calculated values: C, 89.32; H, 7.85; O, 2.83;

[0078] Test values: C, 89.08; H, 8.01; O, 2.98.

[0079] H NMR spectrum: Figure 1 (Compound 1) shown.

[0080] Example 2

[0081] ;

[0082] Step 1 specifically includes the following processes:

[0083] Raw material A-122 (1.2 eq, CAS number: 2568850-23-5), raw material B-122 (1.0 eq, CAS number: 1312598-77-8) and potassium carbonate (3.0 eq) were added to a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and tetrakis(triphenylphosphine)palladium (0.02 eq) was added under nitrogen protection. The temperature was raised to 95°C and refluxed for 5 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered and filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation. The organic phase was retained and concentrated, and intermediate 1 was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) to obtain intermediate 1 (yield: 76.7%).

[0084] Step 2 specifically includes the following processes:

[0085] Intermediate 1 (1.0 eq), pinacol diboron (1.3 eq) and potassium acetate (3.0 eq) were added to a reaction flask, followed by 1,4-dioxane, and tri(dibenzylideneacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added under nitrogen protection. The temperature was raised to 120°C and refluxed for 20 h. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered and filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation. The organic phase was retained and concentrated. The intermediate 2 (yield: 74.7%) was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V=1:4) to obtain the intermediate 2 (yield: 74.7%).

[0086] Step 3 specifically includes the following processes:

[0087] Intermediate 2 (1.0 eq), raw material C-122 (1.0 eq, CAS number: 2330770-73-3) and potassium carbonate (3.0 eq) were added to a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and tetrakis(triphenylphosphine)palladium (0.03 eq) was added under nitrogen protection. The temperature was raised to 95°C and refluxed for 11 hours. The reaction was detected by thin layer chromatography. After the reaction was completed, the temperature was lowered and filtered using diatomaceous earth to remove salt and catalyst. After the filtrate was cooled to room temperature, dichloromethane and water were added for extraction and separation. The organic phase was retained and concentrated, and a mixed solution of dichloromethane and petroleum ether (V:V=1:4) was used for purification by column chromatography to obtain compound 122 (yield: 80.9%).

[0088] The obtained compound 122 was tested and analyzed, and the results were as follows:

[0089] HPLC purity: >99.7%.

[0090] Mass spectrometry test: The model is Waters XEVO TQD mass spectrometer, using ESI source.

[0091] Test value (ESI, m / Z): [M+H] + ):667.61

[0092] Calculated values: C, 89.91; H, 7.69; O, 2.40;

[0093] Test values: C, 89.65; H, 7.83; O, 2.57.

[0094] Example 3-48

[0095] The following compounds were synthesized by referring to the preparation methods of Examples 1 to 2, and tested using a Waters XEVOTQD mass spectrometer with low precision. The ESI source was used for testing, and the mass spectrometry test values ​​are shown in Table 1 below.

[0096] Table 1 Mass spectrometry test values ​​of Examples 3-48

[0097]

[0098] In addition, other compounds of the present invention can be obtained by referring to the methods in the above-mentioned embodiments, so they are not listed one by one here.

[0099] Device Example 1: Preparation of organic electroluminescent device

[0100] The structure of the prepared OLED device is: ITO anode / HIL / HTL / Prime / EML / HBL / ETL / EIL / cathode / CPL.

[0101] a. ITO anode: The ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 1500Å was cleaned twice in distilled water, ultrasonically washed for 30 minutes, and then repeatedly cleaned twice with distilled water, ultrasonically washed for 10 minutes. After washing, it was ultrasonically washed with methanol, acetone, and isopropanol in sequence (5 minutes each time), dried, and then transferred to a plasma cleaning machine for washing for 5 minutes. It was then sent to a vapor deposition machine, and the substrate was used as the anode, and other functional layers were deposited on it in sequence.

[0102] b. HIL (hole injection layer): Hole injection layer materials HT and P-dopant were vacuum evaporated at an evaporation rate of 1Å / s. The chemical formula is shown below. The evaporation rate ratio of HT and P-dopant is 97:3, and the thickness is 10nm.

[0103] c. HTL (hole transport layer): 130nm HT was vacuum-deposited on the hole injection layer at a deposition rate of 1.5Å / s as the hole transport layer.

[0104] d. Prime (luminescence auxiliary layer): 5 nm of Prime was vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a luminescence auxiliary layer.

[0105] e. EML (light-emitting layer): At a deposition rate of 1Å / s, the main material (Compound 1 provided in the above embodiment) and the dopant material (Dopant) are vacuum-deposited on the light-emitting auxiliary layer as a light-emitting layer, with a total thickness of 30nm, wherein the deposition rate ratio of the main compound to the dopant compound is 98:2.

[0106] f. HBL (hole blocking layer): A hole blocking layer HB with a thickness of 5 nm was vacuum-deposited on the light-emitting layer at a deposition rate of 0.5 Å / s.

[0107] g. ETL (electron transport layer): ET and Liq with a thickness of 30 nm were vacuum-deposited on the hole blocking layer at a deposition rate of 1 Å / s as the electron transport layer, wherein the deposition rate ratio of ET to Liq was 50:50.

[0108] h. EIL (electron injection layer): A Yb film with a thickness of 1 nm is vacuum-deposited on the electron transport layer at a deposition rate of 0.5 Å / s to form an electron injection layer.

[0109] i. Cathode: Magnesium and silver with a thickness of 13 nm were vacuum-deposited on the electron injection layer at a deposition rate ratio of 1Å / s. The deposition rate ratio of magnesium to silver was 1:9 to obtain a cathode.

[0110] j. CPL (covering layer): CPL with a thickness of 65 nm was vacuum-deposited on the cathode at a deposition rate of 1 Å / s as a covering layer.

[0111] k. Package the vapor-deposited substrate; first, use the glue coating equipment to coat the cleaned cover with UV glue, then move the coated cover to the pressing section, place the vapor-deposited substrate on the upper end of the cover, and finally bond the substrate and the cover with the bonding equipment, and complete the light curing of the UV glue at the same time.

[0112] The structural formulas of HT, P-dopant, Prime, Dopant, HB, ET, and CPL used in the device embodiment 1 are as follows:

[0113] .

[0114] Device Example 2-48:

[0115] Referring to the method provided in the above device embodiment 1, the corresponding compounds in Table 2 were selected to replace compound 1, and the main material of the light-emitting layer was evaporated to prepare the corresponding organic electroluminescent devices, which were respectively recorded as device embodiments 2-48.

[0116] Device Comparison Examples 1-10:

[0117] Device Comparative Examples 1-10 refer to the method provided in the above device embodiment 1, and the comparative compound aj is used to replace the host material (compound 1) of the light-emitting layer in the above device embodiment 1 for evaporation, and are respectively recorded as device comparative examples 1-10. The chemical structure of the comparative compound aj is as follows:

[0118] .

[0119] The driving voltage, BI and life of the organic electroluminescent devices obtained from the device embodiments 1-48 and the device comparative examples 1-10 were characterized at a brightness of 1000 (nits). The test results are shown in Table 2 below:

[0120] Table 2 Device test results

[0121]

[0122] Those skilled in the art will know that in blue top-emitting devices, the luminous efficiency is greatly affected by chromaticity. Therefore, the influence of chromaticity on efficiency is taken into account, and the ratio of luminous efficiency to CIEy is defined as BI value, that is, BI = (cd / A) / CIEy. In the test, the CIEy value is adjusted in the range of 0.043-0.045.

[0123] It can be seen from Table 2 that the organic electroluminescent device prepared using the luminescent layer host material provided by the present invention has excellent luminous efficiency and service life while maintaining a low driving voltage.

[0124]

[0125] Compounds a, b, c and compounds 15, 117, 171 are parallel comparative examples, the difference between which is that compounds a, b, c are not deuterated, while the 4th and 1st positions of the benzonaphthofuran groups in compounds 15, 117, 171 of the present invention are connected to deuterated groups, the atomic mass of deuterium atoms is about twice that of hydrogen atoms, the vibration frequency of bonds is lower, and the rigidity of molecules is increased, and the rotation and distortion of molecules are reduced, which makes the compounds less likely to decompose at high temperatures, thereby improving the thermal stability of the material, so that the material can still maintain good performance under high temperature operation, thereby extending the service life of the device. In addition, deuteration reduces non-radiative transitions and can improve the luminous efficiency of the device.

[0126]

[0127] Compound eh and compounds 81, 1, 13, and 161 are parallel comparative examples, respectively, and the difference between them is that the connection position of the deuterated benzene ring and the anthracene group on the benzonaphthofuran group in the comparative compound eh is at the ortho or meta position, while the connection position of the deuterated benzene ring and the anthracene group with a deuterated aromatic group in the compounds 81, 1, 13, and 161 of the present invention is at the para position (connected to the 4th and 1st positions on the benzonaphthofuran group, respectively), distributed at the two farthest sites in the benzonaphthofuran group, which can effectively reduce the quenching phenomenon caused by aggregation, and also form a more effective conjugated system, enhance the charge transfer and energy transfer within the molecule, which helps to improve the fluorescence quantum efficiency of the material, thereby improving the luminescence efficiency of the device.

[0128] In addition, in the comparative compound g, the anthracene group is connected to a deuterated heteroaryl group (dibenzofuran group), while in the compound 13 of the present invention, the anthracene group is connected to a deuterated aromatic group (9,9-dimethylfluorene group). The 9,9-dimethylfluorene group structure has a high fluorescence quantum efficiency, and the HOMO and LUMO energy levels of the structure are moderate, which can match well with other functional layers in the device, promote effective carrier injection and transport, and thus improve the luminescence efficiency of the material device.

[0129] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A blue light host material, characterized in that: The structure of the blue light host material is shown in Chemical Formula I: ； in, Ar is independently selected from phenyl, and the position of the phenyl ring on the dibenzofuran group is 1, 2, 2, 3 or 3, 4, and the connection position is as follows: ; R1 is independently selected from a C6-C30 aryl group fully or partially substituted by deuterium, a C2-C30 heteroaryl group fully or partially substituted by deuterium, or a combination of the above aryl groups and heteroaryl groups, wherein the heteroatom in the heteroaryl group contains at least one of O, S, N, Si, and Se; R2 is independently selected from C6-C30 aryl groups fully or partially substituted by deuterium.

2. The blue light host material according to claim 1, characterized in that: The structure of the blue light host material is specifically as follows: 。 3. The blue light host material according to claim 1 or 2, characterized in that: R1 is independently selected from a C6-C18 aryl group fully or partially substituted by deuterium, a C5-C24 heteroaryl group fully or partially substituted by deuterium, or a combination of the above aryl groups and heteroaryl groups, wherein the heteroatom in the heteroaryl group contains at least one of O, S, N, Si, and Se; R2 is independently selected from C6-C18 aryl groups fully or partially substituted by deuterium.

4. The blue light host material according to claim 3, characterized in that: R1 is selected from the following groups or any combination: ， * indicates a connection point; where R3-R 15 Each is independently selected from deuterium, C1-C6 alkyl partially or fully substituted by deuterium; n3、n 10 Each is independently selected from 0, 1, 2, 3, 4, 5; n4 and n7 are each independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9; n5、n 13 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13; n6 and n8 are each independently selected from 0, 1, 2, 3, 4, 5, 6, and 7; n9、n 15 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8; n 11 Independently selected from 0, 1, 2, 3, 4; n 12 、n 14 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11.

5. The blue light host material according to claim 3, characterized in that: R2 is selected from the following groups or any combination: ， * indicates a connection point; where R 16 -R 24 Each is independently selected from deuterium, C1-C6 alkyl partially or fully substituted by deuterium; n 16 Each is independently selected from 0, 1, 2, 3, 4, 5; n 17 、n 20 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9; n 18 、n 23 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13; n 19 、n 21 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7; n 22 、n 24 Each is independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11.

6. The blue light host material according to claim 1, characterized in that: The structure of the blue light host material includes but is not limited to any one of the following compounds: 。 7. A method for preparing a blue light host material as claimed in claim 1, characterized in that: The method operates as follows: Step 1 specifically includes the following processes: 1.0-1.2eq of raw material A, 1.0eq of raw material B and 2.0-4.0eq of potassium carbonate are added to a reaction flask, followed by a mixed solution of toluene, ethanol and water in a volume ratio of 3:1:1, and 0.01-0.03eq of tetrakis(triphenylphosphine)palladium is added under nitrogen protection, and the temperature is raised to 85°C-95°C, and the reaction is refluxed for 3-24h; the reaction is detected by thin layer chromatography, and after the reaction is completed, the temperature is lowered, and diatomaceous earth is used for filtering to remove salt and catalyst, and the filtrate is cooled to room temperature, and then dichloromethane and water are added for extraction and separation, and the organic phase is retained and concentrated, and a mixed solution of dichloromethane and petroleum ether in a volume ratio of 1:3-1:8 is used for purification by column chromatography to obtain intermediate 1; Step 2 Specific The process includes: 1.0 eq of intermediate 1, 1.0-2.0 eq of pinacol diboron and 2.0-4.0 eq of potassium acetate are added to a reaction bottle, followed by 1,4-dioxane, and 0.02-0.10 eq of tris(dibenzylideneacetone)dipalladium and 0.1-0.2 eq of X-Phos are added under nitrogen protection, and the temperature is raised to 110-120° C., and the reaction is refluxed for 3-24 hours; the reaction is detected by thin layer chromatography, and after the reaction is completed, the temperature is lowered, and diatomaceous earth is used for filtering to remove salt and catalyst, and the filtrate is cooled to room temperature, and then dichloromethane and water are added for extraction and separation, and the organic phase is retained and concentrated, and a mixed solution of dichloromethane and petroleum ether with a volume ratio of 1:3-1:8 is used to purify by column chromatography to obtain intermediate 2; Step 3 Specific The process includes: 1.0-1.3eq of intermediate 2, 1.0eq of raw material C and 2.0-4.0eq of potassium carbonate are added to a reaction flask, followed by a mixed solution of toluene, ethanol and water in a volume ratio of 3:1:1, and 0.01-0.03eq of tetrakis(triphenylphosphine)palladium is added under nitrogen protection, and the temperature is raised to 85°C-95°C, and the reaction is refluxed for 3-24h; the reaction is detected by thin layer chromatography, and after the reaction is completed, the temperature is lowered, and diatomaceous earth is used for filtering to remove salt and catalyst, and the filtrate is cooled to room temperature, and then dichloromethane and water are added for extraction and separation, and the organic phase is retained and concentrated, and a mixed solution of dichloromethane and petroleum ether in a volume ratio of 1:3-1:8 is used for purification by column chromatography to obtain chemical formula I; The specific synthetic route is as follows: ； In the above formula, Ar, R1, R2 are as defined in the above chemical formula I, and X represents or .

8. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the blue light host material as claimed in claim 1.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and at least one organic thin film layer arranged between the first electrode and the second electrode; the organic thin film layer comprises the blue light host material.

10. The organic electroluminescent device according to claim 9, characterized in that: The blue light host material is used as the host material of the light-emitting layer of the organic electroluminescent device.

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