Blue host material, preparation method and organic electroluminescent device

Abstract

The application 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 shown in chemical formula I.The blue light host material provided by the application can reduce the driving voltage of a photoelectric device, improve the luminous efficiency of the photoelectric device, and prolong the service life of the photoelectric device when the blue light host material is used in the organic electroluminescent device.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic electroluminescent materials, and particularly relates to a blue light host material, a preparation method and an organic electroluminescent device. BACKGROUND

[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 utilize singlet excitons, while triplet excitons are severely wasted, the electroluminescent device based on fluorescent materials has relatively low performance. However, the color purity and stability of blue fluorescent materials are much better than those of blue phosphor materials and thermally delayed fluorescent materials, and most of the blue materials in the current industrialized three primary color materials use fluorescent materials. Therefore, the development and application of blue fluorescent materials still attract a large number of researchers and enterprises.

[0003] At present, the light-emitting layer in the blue organic electroluminescent device almost entirely uses a host-guest doped light-emitting system, that is, the host material and the guest doped material are doped together to realize electroluminescence. The host material in the device must have good film-forming property, thermal stability, electrochemical property and carrier transport property. When designing and selecting the host material, the following requirements should be met: (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 region in the device can be effectively limited in the light-emitting layer; (3) the triplet energy level of the host material should be higher than that of the light-emitting material, so as to prevent unnecessary energy loss caused by energy transfer from the light-emitting material to the host material, and affect the performance of the device; (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, so as to reduce the energy gap difference of hole or electron injection, and reduce the working voltage of the device.

[0004] The development and selection of the host material have a great influence on the performance of the device. The commonly used blue fluorescent device mainly adopts anthracene-based host materials. Due to the large planar conjugated structure of anthracene group, the anthracene derivative has high fluorescence quantum efficiency, high carrier mobility and strong charge injection ability, so it has high commercial application value. However, due to the strong π-π stacking between molecules, the efficiency of the blue light material which originally has good performance is reduced, the emission wavelength is red-shifted, and the color purity is reduced, which limits its application in solid-state lighting. Therefore, the development of anthracene derivatives cannot stop. SUMMARY

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

[0006] It should be noted that the application provides a compound which can be used as a blue light host material in a light-emitting layer, and the compound has a main nuclear skeleton of a deuterated anthracene group and a rigid benzonaphthofuran group, has good thermal stability and film-forming property, and has a deuterated aryl group introduced on the deuterated anthracene group, so that the conjugated system can be effectively extended, other functional layers can be more easily matched, the light-emitting efficiency of the device can be improved, and the service life can be prolonged.

[0007] In order to achieve the above-mentioned purpose, the first object of the application is to provide a blue light host material.

[0008] A blue light host material, the structure general formula of the blue light material is chemical formula I:

[0009] ;

[0010] Among them,

[0011] Ar is independently selected from a phenyl group, and the phenyl group is located at positions 1, 2, 2, 3 or 3, 4 on the di-benzofuran group, and the connection position is as follows: ;

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

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

[0014] Further, the chemical formula I is preferably as follows:

[0015] .

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

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

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

[0019] , * indicates a connection point; wherein,

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

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

[0022] n4, n7each independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9;

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

[0024] n6, n8each independently selected from 0, 1, 2, 3, 4, 5, 6, 7;

[0025] n9, n 15 each 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 independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11.

[0028] Still further, R2is independently selected from the following groups or any combination thereof:

[0029] , * indicates the point of attachment; wherein,

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

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

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

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

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

[0035] n 22 、n 24 each independently selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 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 application is to provide a preparation method of the blue light host material as described above.

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

[0040] ;

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

[0042] In particular, for the complex raw materials which have not been disclosed, the classical Suzuki coupling reaction and bromination reaction are adopted to synthesize and apply to the present application.

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

[0044] Step 1 specifically includes the following process:

[0045] The raw material A (1.0-1.2 eq), the raw material B (1.0 eq) and potassium carbonate (2.0-4.0 eq) are added into a reaction bottle, then a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1) is added, under the protection of nitrogen, tetrakis(triphenylphosphine)palladium (0.01-0.03 eq) is added, the temperature is raised to 85-95 DEG C, and the reaction is refluxed for 3-24 h; the reaction is detected by using thin layer chromatography, after the reaction is completed, the temperature is lowered, diatomite is used for filtration, the salt and the catalyst are removed, after the filtrate is cooled to room temperature, dichloromethane and water are added for extraction and separation, the organic phase is reserved and concentrated, a mixed solution of dichloromethane and petroleum ether (V:V = 1:3-1:8) is used for purification by column chromatography to obtain the intermediate 1;

[0046] The step 2 specifically comprises the following process:

[0047] The intermediate 1 (1.0 eq), pinacol diborane (1.0-2.0 eq) and potassium acetate (2.0-4.0 eq) are added into a reaction bottle, then 1,4-dioxane is added, under the protection of nitrogen, tris(dibenzylideneacetone)dipalladium (0.02-0.10 eq) and X-Phos (0.1-0.2 eq) are added, the temperature is raised to 110-120 DEG C, and the reaction is refluxed for 3-24 h; the reaction is detected by using thin layer chromatography, after the reaction is completed, the temperature is lowered, diatomite is used for filtration, the salt and the catalyst are removed, after the filtrate is cooled to room temperature, dichloromethane and water are added for extraction and separation, the organic phase is reserved and concentrated, a mixed solution of dichloromethane and petroleum ether (V:V = 1:3-1:8) is used for purification by column chromatography to obtain the intermediate 2;

[0048] The step 3 specifically comprises the following process:

[0049] The intermediate 2 (1.0-1.3 eq), the raw material C (1.0 eq) and potassium carbonate (2.0-4.0 eq) are added into a reaction bottle, then a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1) is added, under the protection of nitrogen, tetrakis(triphenylphosphine)palladium (0.01-0.03 eq) is added, the temperature is raised to 85-95 DEG C, and the reaction is refluxed for 3-24 h; the reaction is detected by using thin layer chromatography, after the reaction is completed, the temperature is lowered, diatomite is used for filtration, the salt and the catalyst are removed, after the filtrate is cooled to room temperature, dichloromethane and water are added for extraction and separation, the organic phase is reserved and concentrated, a mixed solution of dichloromethane and petroleum ether (V:V = 1:3-1:8) is used for purification by column chromatography to obtain the chemical formula I.

[0050] A third object of the present application is to provide an organic electroluminescence device comprising the blue 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] The blue light host material is used as a light-emitting layer host material of an organic electroluminescent device.

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

[0054] The compound disclosed in the present application is used as a blue light host material, the structure takes a deuterated anthracene group and a benzonaphthofuran group as a mother nucleus 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 larger conjugated system and a higher fluorescence quantum efficiency, especially in the blue light region, the rigid planar structure reduces the possibility of non-radiative transition, effectively improves the electron mobility, and thus improves the luminous efficiency of blue light. The low-lying unoccupied molecular orbital (LUMO) energy level is beneficial to the injection and transport of electrons. The structure of the anthracene group is relatively stable and can withstand high temperature, so that the structure is not easy to change during evaporation, thereby improving the service life of the device. In addition, the anthracene group also has a wide band gap, which makes it have strong absorption and emission ability in the blue light region. Deuterating the anthracene group can reduce the molecular vibration frequency and reduce the molecular thermal motion, which helps to improve the thermal stability of the material, reduces the degradation of the material caused by temperature rise, and prolongs the service life of the material. Because D has lower activity than H, the C-D bond is more stable than the C-H bond in structure, the non-radiative transition of the compound is reduced, the structure is more stable, and it is beneficial to improve the service life and efficiency of the material used in the device. In addition, the introduction of a capping group (deuterated aryl) on the anthracene group, the HOMO energy level of the aryl group is usually high, and the LUMO energy level is usually low, which makes the energy gap (HOMO-LUMO energy level difference) of the aryl group larger, more easily matching other functional layers, and the performance of the device is more excellent.

[0056] 2) The introduction of the rigid benzonaphtho group helps to improve the thermal stability of the material, thereby enhancing the service life of the device. The fragment containing the large electronegativity oxygen atom in the benzonaphthofuran group can effectively improve the luminous efficiency of the blue light device. Further introducing a substituent group (aryl or heteroaryl) on the benzonaphthofuran group can effectively extend the conjugated system and enhance the conjugation effect, improve the fluorescence quantum efficiency, and avoid the localization of carrier migration, thereby improving the migration rate, reducing the voltage and improving the luminous efficiency of the device.

[0057] 3) The benzochrysenofuran group is connected with deuterated anthracene group at 1 position and deuterated aryl or heteroaryl group at 4 position, which are the most distant two positions in the benzochrysene group, not only can effectively reduce the quenching phenomenon caused by aggregation, but also form a more effective conjugated system, enhance the intramolecular charge transfer and energy transfer, which is helpful to improve the fluorescence quantum efficiency of the material and improve the luminous efficiency of the device. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are only a part of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0059] Figure 1 The nuclear magnetic resonance hydrogen spectrum of compound 1 provided for embodiment 1 of the present application. DETAILED DESCRIPTION

[0060] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application and related drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0061] The present application specifically discloses a blue light host material, a preparation method and an organic electroluminescent device.

[0062] It should be noted that the numerical values given in the following embodiments 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, not an absolutely accurate number.

[0063] The features and properties of the present application will be further described in detail below in combination with the embodiments.

[0064] Embodiment 1

[0065] ;

[0066] Step 1 specifically includes the following process:

[0067] Into a reaction flask, raw material A-1 (1.2 eq, CAS No. 2660005-47-8), raw material B-1 (1.0 eq, CAS No. 215527-70-1) and potassium carbonate (3.0 eq) were added, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then tetrakis(triphenylphosphine)palladium (0.02 eq) was added under nitrogen protection. The reaction was heated to 95°C and refluxed for 4 h. After the reaction was completed, the temperature was lowered, and the salt and catalyst were removed by filtration using diatomite. The filtrate was cooled to room temperature, extracted with dichloromethane and water, and then separated into two layers. The organic phase was concentrated, and then 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 process:

[0069] Into a reaction flask, intermediate 1 (1.0 eq), bis(pinacolato)diboron (1.3 eq) and potassium acetate (3.0 eq) were added, followed by 1,4-dioxane. Then, tris(dibenzylideneacetone)dipalladium (0.03 eq) and X-Phos (0.2 eq) were added under nitrogen protection. The reaction was heated to 120°C and refluxed for 18 h. After the reaction was completed, the temperature was lowered, and the salt and catalyst were removed by filtration using diatomite. The filtrate was cooled to room temperature, extracted with dichloromethane and water, and then separated into two layers. The organic phase was concentrated, and then purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to obtain intermediate 2 (yield: 75.4%).

[0070] Step 3 specifically includes the following process:

[0071] Into a reaction flask, intermediate 2 (1.0 eq), raw material C-1 (1.0 eq, CAS No. 2377545-68-9) and potassium carbonate (3.0 eq) were added, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), and then tetrakis(triphenylphosphine)palladium (0.03 eq) was added under nitrogen protection. The reaction was heated to 95°C and refluxed for 10 h. After the reaction was completed, the temperature was lowered, and the salt and catalyst were removed by filtration using diatomite. The filtrate was cooled to room temperature, extracted with dichloromethane and water, and then separated into two layers. The organic phase was concentrated, and then purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:5) to obtain compound 1 (yield: 82.2%).

[0072] The obtained compound 1 was subjected to detection and analysis, and the results were as follows:

[0073] HPLC purity: >99.8%.

[0074] Mass spectrometry test: Mass spectrometer of Waters XEVO TQD type, using ESI source.

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

[0076] Elemental analysis:

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

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

[0079] Nuclear magnetic resonance hydrogen spectrum: as shown in Figure 1 (Compound 1).

[0080] Example 2

[0081] ;

[0082] Step 1 specifically includes the following process:

[0083] The raw material A-122 (1.2 eq, CAS number: 2568850-23-5), the raw material B-122 (1.0 eq, CAS number: 1312598-77-8) and potassium carbonate (3.0 eq) are added to the reaction bottle, followed by adding a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), adding tetrakis (triphenylphosphine) palladium (0.02 eq) under nitrogen protection, heating to 95°C, and refluxing for 5h; the reaction is detected by thin layer chromatography, after the reaction is completed, cooling, filtering with diatomite to remove salt and catalyst, after the filtrate is cooled to room temperature, adding dichloromethane and water to extract and separate, retaining the organic phase to concentrate, using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to purify by column chromatography to obtain the intermediate 1 (yield: 76.7%).

[0084] Step 2 specifically includes the following process:

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

[0086] Step 3 specifically includes the following process:

[0087] Intermediate 2 (1.0 eq), raw material C-122 (1.0 eq, CAS No.: 2330770-73-3) and potassium carbonate (3.0 eq) were added into a reaction flask, followed by a mixed solution of toluene, ethanol and water (V:V:V = 3:1:1), tetrakis(triphenylphosphine)palladium (0.03 eq) was added under nitrogen protection, the temperature was raised to 95 °C, and the reaction was refluxed for 11 h; the reaction was detected by thin layer chromatography, after the reaction was completed, the temperature was lowered, diatomite was used for filtration to remove the salt and catalyst, the filtrate was cooled to room temperature, extracted with dichloromethane and water, separated, the organic phase was retained and concentrated, purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to obtain compound 122 (yield: 80.9%).

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

[0089] HPLC purity: >99.7%.

[0090] Mass spectrometry test: mass spectrometer of Waters XEVO TQD type, using ESI source.

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

[0092] The test value was: C, 89.65; H, 7.83; O, 2.57.

[0093] The test value was: C, 89.65; H, 7.83; O, 2.57.

[0094] Example 3-48

[0095] The following compounds were synthesized according to the preparation method of Examples 1 to 2, and tested by using a mass spectrometer of Waters XEVOTQD, which has low accuracy, and an ESI source, 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 application can be obtained according to the method of the above-mentioned examples, and thus are not listed one by one herein.

[0099] Device Example 1: Preparation of an 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 1500 angstroms was cleaned twice in distilled water, ultrasonic washing for 30 min, and then repeatedly cleaned twice in distilled water, ultrasonic washing for 10 min. After washing, methanol, acetone, and isopropanol were sequentially ultrasonic washed (5 min each time), dried, and then transferred to a plasma cleaning machine for washing for 5 min, and then sent to an evaporation machine. The substrate was used as an anode, and other functional layers were sequentially evaporated thereon.

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

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

[0104] d. Prime (light-emitting auxiliary layer): 5 nm of Prime as a light-emitting auxiliary layer was vacuum evaporated on the hole transport layer at a rate of 0.5 angstrom / s.

[0105] e. EML (emitting layer): The host material (compound 1 provided in the above examples) and the dopant material (Dopant) were vacuum evaporated on the light-emitting auxiliary layer as an emitting layer at a rate of 1 angstrom / s, with a total thickness of 30 nm. The evaporation rate ratio of the host compound and the dopant compound was 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 A / 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 A / s as an electron transport layer, wherein the deposition rate ratio of ET to Liq was 50:50.

[0108] h、EIL (electron injection layer): a Yb film layer with a thickness of 1 nm was vacuum deposited on the electron transport layer at a deposition rate of 0.5 A / 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 of 1 A / s, and the deposition rate ratio of magnesium to silver was 1:9 to obtain a cathode.

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

[0111] k、The substrate after deposition was packaged; first, the cleaned cover plate was coated with UV glue using a gluing device, then the coated cover plate was moved to the pressing section, the substrate after deposition was placed on the end of the cover plate, and finally the substrate and the cover plate were bonded under the action of the bonding device, and the UV glue was cured by light.

[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 embodiments 2-48:

[0115] Referring to the method provided in the device embodiment 1, the corresponding compounds in Table 2 were respectively selected to replace compound 1 to perform the deposition of the light-emitting layer host material, and the corresponding organic electroluminescent devices were prepared and were respectively recorded as device embodiments 2-48.

[0116] Device comparative examples 1-10:

[0117] Device comparative examples 1-10 refer to the method provided in the device embodiment 1, and comparative compounds a-j are respectively used to replace the host material (compound 1) of the light-emitting layer in the device embodiment 1 to perform deposition, and are respectively recorded as device comparative examples 1-10. The chemical structural formulas of the comparative compounds a-j are as follows:

[0118] .

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

[0120] Table 2 Device test results

[0121]

[0122] It is known to those skilled in the art that in a blue top-emitting device, the luminous efficiency is greatly affected by chromaticity, so the factor of the influence of chromaticity on efficiency is considered, and the luminous efficiency and CIEy ratio are defined as BI value, that is, BI = (cd / A) / CIEy, and the range of CIEy value is controlled between 0.043-0.045 in the test.

[0123] As can be seen from Table 2, the organic electroluminescent device prepared using the light-emitting layer host material provided by the present application 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 is that there is no deuterium on compounds a, b, c, while the groups connected to the 4th and 1st positions of the benzonaphthofuran group in the compounds 15, 117, 171 of the present application are deuterated groups, the atomic mass of deuterium is about twice that of hydrogen, the vibration frequency of the bond is lower, and the rigidity of the molecule is also increased, reducing the rotation and twisting of the molecule, which makes the compound not easy to decompose at high temperature, thereby improving the thermal stability of the material, so that the material can still maintain good performance under high temperature operation, thereby prolonging the service life of the device. In addition, deuterium substitution reduces non-radiative transitions, which can improve the luminous efficiency of the device.

[0126]

[0127] Compounds e-h and compounds 81, 1, 13, 161 are parallel comparative examples, which are different from the present application in that the position of the deuterated benzene ring and the anthracene group on the benzonaphthofuran group in the comparative compounds e-h is ortho or meta, while the position of the deuterated benzene ring and the anthracene group with deuterated aryl in the compounds 81, 1, 13, 161 of the present application is para (connected to the 4-position and 1-position of the benzonaphthofuran group, respectively), which is the farthest distance in the benzonaphthofuran group, can effectively reduce the quenching phenomenon caused by aggregation, and also form a more effective conjugated system, enhance the intramolecular charge transfer and energy transfer, which helps to improve the fluorescence quantum efficiency of the material, thereby improving the luminous efficiency of the device.

[0128] In addition, the anthracene group in the comparative compound g is connected to the deuterated heteroaryl (dibenzofuran group) below, while the anthracene group in the compound 13 of the present application is connected to the deuterated aryl (9,9-dimethylfluorene group), and the 9,9-dimethylfluorene group has a higher fluorescence quantum efficiency, and the HOMO and LUMO energy levels of the structure are moderate, which can be well matched with other functional layers in the device, promoting effective carrier injection and transport, thereby improving the luminous efficiency of the material device.

[0129] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Accordingly, the application is not to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A blue host material, characterized by, The structure of the blue host material is any one of the following compounds: 。 2. An organic electroluminescent device, characterized by The organic electroluminescent device comprises the blue host material according to claim 1.

3. The organic electroluminescent device according to claim 2, 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 host material.

4. The organic electroluminescent device according to claim 3, characterized in that The blue host material is used as a light-emitting layer host material of an organic electroluminescent device.

Images