Heterocyclic compound based on fluorene and carbazole / acridine and application of heterocyclic compound in organic electroluminescent device

Abstract

The invention provides a heterocyclic compound based on fluorene and carbazole / acridine and application of the heterocyclic compound in an organic electroluminescent device, the compound has a structure shown in a formula (1), and the compound can improve the luminance and luminous efficiency of the organic electroluminescent device and reduce efficiency roll-off.

Description

Technical Field

[0001] The invention belongs to the field of organic electroluminescent materials, and in particular relates to a heterocyclic compound based on fluorene and carbazole / acridine and application of the heterocyclic compound in an organic electroluminescent device. Background Art

[0002] In 1987, Professor Qingyun Deng, a Chinese American scientist, first reported a novel catalytic reaction based on triarylamine and A1Q. 3 Double-layer organic light-emitting devices (OLEDs). Compared with traditional liquid crystal displays, OLEDs have many advantages: self-luminescence, high contrast, ultra-thin, foldable, low power consumption, etc., and are therefore considered the future of display and lighting technology.

[0003] The luminescent materials used in OLEDs have gone through a development process from traditional fluorescence, phosphorescence to thermally activated delayed fluorescence, and the internal quantum efficiency has gradually increased from 25% to 100%.

[0004] Thermally activated delayed fluorescence (TADF) is a technology that currently attracts much attention for utilizing triplet exciton energy. Professor Adachi of Kyushu University in Japan discovered a thermally activated delayed fluorescence material based on triplet-singlet transitions, which can utilize the heat of the surrounding environment to promote the reverse transfer of energy from the triplet excited state to the singlet excited state, thereby achieving high luminescence efficiency without relying on expensive rare metals. The thermally activated sensitized delayed fluorescence (TASF) mechanism proposed by Professor Duan Lian of Tsinghua University is centered on converting the triplet energy of the excited state into the singlet energy of the excited state through an upconversion process, and then transferring the energy to the excited singlet state of the dye through the Foxter energy transfer mechanism, ultimately achieving luminescence, thereby separating the energy harvesting from the luminescence process.

[0005] At present, in the device structure of the display and lighting field, blue fluorescence is generally used in combination with red and green phosphorescent materials. The efficiency of blue fluorescence and the cost and color purity of phosphorescent materials directly affect the performance of organic electroluminescent devices. The light-emitting layer of common electroluminescent devices mainly uses host-guest doping to adjust its light color, brightness and efficiency, thereby improving device performance.

[0006] Since most common host materials have wide band gaps and unipolar transmission characteristics, they often lead to exciton injection barriers and high turn-on voltages. In addition, due to unbalanced carrier transmission, the exciton conformity region deviates under high voltage, causing changes in the luminescence spectrum and serious efficiency roll-off problems. In order to prepare organic electroluminescent devices with lower driving voltage, better luminous efficiency, lower efficiency roll-off, and longer device life, and to continuously improve the performance of the devices, it is necessary not only to innovate the device structure and manufacturing process, but also to continuously study and innovate the optoelectronic functional materials in the device to prepare functional materials with higher performance. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a heterocyclic compound based on fluorene and carbazole / acridine and its application in an organic electroluminescent device. The compound of the present invention can improve the luminous brightness and luminous efficiency of the organic electroluminescent device and reduce the efficiency roll-off.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In one aspect, the present invention provides a heterocyclic compound based on fluorene and carbazole / acridine, wherein the compound has a structure as shown in the following formula (1):

[0010]

[0011] wherein n is 0 or 1; R is selected from at least one of a C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; A 1 and A 2 Each independently selects at least one of a cyano group and a trifluoromethyl group;

[0012] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 1 '、R 2 '、R 3 '、R 4 '、R 5 '、R 6 '、R 7 '、R 8 ' and R 9 'Each independently selects hydrogen atoms, C 1 ~C 10 Alkyl, substituted or unsubstituted C 6~C 30 Aryl and substituted or unsubstituted C 3 ~C 30 At least one of heteroaryl groups.

[0013] Preferably, the heterocyclic compound based on fluorene and carbazole / acridine has any one of the general formula (II-1) or general formula (II-2):

[0014]

[0015] In the general formula (II-1) and the general formula (II-2), A 1 , A 2 , R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 1’ , R 2’ , R 3’ , R 4’ , R 5 ‘ , R 6’ , R 7’ , R 8’ and R 9’ The meaning is the same as in claim 1.

[0016] In the general formula (II-2), R10, R11, R10' and R11' are each independently selected from at least one of a C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group and a substituted or unsubstituted C3-C30 heteroaryl group.

[0017] Preferably, the C 1 ~C 10 The alkyl group is selected from at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl.

[0018] The substituted or unsubstituted C 6 ~C 30The aryl group is selected from at least one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted indenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted benzofluorenyl, substituted or unsubstituted 9,9'-dialkylfluorenyl, substituted or unsubstituted 9,9-spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted triphenylene, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted cyanol and substituted or unsubstituted tetraphenylcyanol.

[0019] The substituted or unsubstituted C 1 ~C 30 The heteroaryl group is selected from at least one of a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzoselenophene group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, and a substituted or unsubstituted benzocarbazolyl group.

[0020] Preferably, the substituent in the substituted group is selected from one of methyl, tert-butyl, phenyl or carbazole.

[0021] The heterocyclic compound based on fluorene and carbazole / acridine preferably forms a symmetrical structure, i.e. 1 and A 2 Same, R 1 With R 1 'Same, R 2 With R 2 'Same, R 3 With R 3 'Same, R 4 With R 4 'Same, R 5 With R 5 'Same, R 6 With R 6 'Same, R 7 With R 7 'Same, R 8 With R 8 'Same, R 9 With R 9 'Same, R 10 With R 10 'Same, R 11 With R 11 'Same, the symmetrical structure has stronger electron transmission ability and the rigid twisted structure has a larger range, which is more conducive to improving the luminous efficiency of the device.

[0022] The second aspect of the present invention provides use of the heterocyclic compound based on fluorene and carbazole / acridine described in the first aspect of the present invention in the preparation of an organic electroluminescent device.

[0023] The third aspect of the present invention provides an organic electroluminescent device, comprising a substrate, an anode layer, a cathode layer, and at least one organic functional layer between the anode layer and the cathode layer, wherein the organic functional layer comprises a hole injection layer, a hole transport layer, an organic light-emitting layer, an electron transport layer and an electron injection layer, and the organic functional layer contains the heterocyclic compound based on fluorene and carbazole / acridine as described in the first aspect.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] In the heterocyclic compound of fluorene and carbazole / acridine of the present invention, the fluorene and carbazole / acridine groups have a relatively high triplet energy level, and when connected by a σ bond, the conjugation degree will not be greatly improved, and the triplet energy level is still relatively high, so the compounds can be used as the main material of red, green and blue light-emitting materials. In addition, the energy gap of the series of compounds is relatively narrow, which is conducive to the injection of carriers and can effectively reduce the turn-on voltage of the device. The fluorene and acridine / carbazole groups both have good hole transport capabilities, and when used in the light-emitting layer of the organic electroluminescent device, the recombination area of ​​the carriers can be expanded, and the efficiency roll-off can be effectively reduced. At the same time, the heterocyclic compound of the present invention has a fluorene group structure connected to the carbazole / acridine, and the large steric hindrance effect of the fluorene group can increase the molecular distance, reduce Dexter energy transfer, reduce exciton loss, effectively reduce quenching caused by aggregation, and can improve the luminous efficiency of the organic electroluminescent device and reduce the efficiency roll-off. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0027] The first aspect of the present invention provides a heterocyclic compound based on fluorene and carbazole / acridine, wherein the heterocyclic compound has a structure shown in the following formula (1):

[0028]

[0029] According to the present invention, n is 0 or 1; R is selected from at least one of a C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group. 1 and A 2 Each independently selects at least one of a cyano group and a trifluoromethyl group, A 1 With A 2 Can be the same or different, preferably the same; R 1 , R 2 , R 3 , R 4 , R5 , R 6 , R 7 , R 8 , R 9 , R 1 '、R 2 '、R 3 '、R 4 '、R 5 '、R 6 '、R 7 '、R 8 ' and R 9 'Each independently selects hydrogen atoms, C 1 ~C 10 Alkyl, substituted or unsubstituted C 6 ~C 30 Aryl and substituted or unsubstituted C 3 ~C 30 At least one of heteroaryl groups.

[0030] Preferably, the heterocyclic compound based on fluorene and carbazole / acridine has any one of the general formula (II-1) or general formula (II-2):

[0031]

[0032]

[0033] In the general formula (II-1) and the general formula (II-2), A 1 , A 2 , R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 1 '、R 2 '、R 3 '、R 4 '、R 5 '、R 6 '、R 7 '、R 8 ' and R 9 ' has the same meaning as in claim 1.

[0034] In the general formula (II-2), R 10 , R 11 , R 10 '、R 11'Each independently select at least one of a C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group.

[0035] Preferably a symmetrical structure is formed, i.e. A 1 and A 2 Same, R 1 With R 1 'Same, R 2 With R 2 'Same, R 3 With R 3 'Same, R 4 With R 4 'Same, R 5 With R 5 'Same, R 6 With R 6 'Same, R 7 With R 7 'Same, R 8 With R 8 'Same, R 9 With R 9 'same; when n is 1, in addition to meeting the above conditions, R 10 With R 10 'Same, R 11 With R 11 'same.

[0036] In the present invention, the C1-C10 may be C1, C2, C3, C4, C5, C6, C7, C8, C9 or C10, the C6-C30 may be C6, C8, C10, C12, C14, C18, C20, C22, C24, C26, C28 or C30, and the C3-C30 may be C3, C4, C5, C6, C8, C10, C12, C14, C18, C20, C22, C24, C26, C28 or C30.

[0037] According to the present invention, C 1 ~C 10 The alkyl group is well known to those skilled in the art, i.e., an aliphatic alkyl group having 1 to 10 carbon atoms, and may be at least one selected from methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl and decyl, wherein the alkyl group may be a linear alkyl group or an alkyl group with a branch, and is further preferably at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; the above alkyl groups are preferably methyl, ethyl and tert-butyl.

[0038] According to the present invention, the substituted or unsubstituted C 6 ~C 30The aryl group is selected from at least one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted indenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted benzofluorenyl, substituted or unsubstituted 9,9'-dialkylfluorenyl, substituted or unsubstituted 9,9'-spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted triphenylene, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted cyano and substituted or unsubstituted tetraphenylcyano; preferably substituted or unsubstituted phenyl; further, the substituent in the substituted phenyl is preferably methyl, tert-butyl or phenyl.

[0039] According to the present invention, the substituted or unsubstituted C 1 ~C 30 The heteroaryl group is selected from at least one of substituted or unsubstituted dibenzothiophenyl, substituted or unsubstituted dibenzoselenophene, substituted or unsubstituted dibenzofuranyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted azacarbazolyl, and substituted or unsubstituted benzocarbazolyl. Preferably, the heteroaryl group is substituted or unsubstituted carbazolyl, and the substituent in the substituted carbazolyl group is selected from one of methyl, tert-butyl or phenyl.

[0040] According to the present invention, in order to further improve the electron transport ability of the heterocyclic compound, the number of substituents on the two benzene rings of the fluorenyl group is not limited, and can be 0 to 4, preferably 0 to 2, and more preferably no substituent or one substituent, and the substitution position is preferably R 2 , R 2 '、R 3 , R 3 ', and all other positions are hydrogen atoms. The substituents are preferably methyl, tert-butyl, or phenyl. The substituents on the two benzene rings of fluorene may correspond or not correspond, preferably they correspond, i.e., symmetrical substitution.

[0041] According to the present invention, the number of substituents on the carbazole / acridine group is not limited and can be 0 to 2. In a preferred embodiment of the present invention, there is no substituent or only one substituent on the two benzene rings of the carbazole / acridine group, and the position of the substituent is preferably R 7 With R 7 ' position. That is, R 5 , R 6 , R 7 , R 8 , R 9 , R 5 '、R 6 '、R 7 '、R 8 ' and R 9 'are all hydrogen atoms; or R 5, R 6 , R 8 , R 9 , R 5 '、R 6 '、R 8 ' and R 9 ' are all hydrogen atoms, R 7 and R 7 ' has a substituent. The substituent is preferably C 1 ~C 10 Alkyl, substituted or unsubstituted C 6 ~C 30 Aryl and substituted or unsubstituted C 3 ~C 30 At least one of the heteroaryl groups; more preferably a methyl group, a tert-butyl group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted carbazolyl group, and more preferably a phenyl group or a carbazolyl group.

[0042] According to the present invention, the heterocyclic compound based on fluorene and carbazole / acridine can be selected from any one of the following compounds:

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049] The second aspect of the present invention provides use of the heterocyclic compound based on fluorene and carbazole / acridine described in the first aspect of the present invention in the preparation of an organic electroluminescent device.

[0050] According to the present invention, the heterocyclic compound based on fluorene and carbazole / acridine has good electron transport performance and high triplet energy level, and can be used as the light-emitting material of the organic electroluminescent device, preferably as the host material and / or guest material of the light-emitting layer.

[0051] According to the present invention, the luminescent material may be known to those skilled in the art, for example, it may be at least one of a fluorescent material, a phosphorescent material and a thermally activated delayed fluorescence (TADF) material. Among them, the TADF material can effectively utilize triplet excitons to achieve an internal quantum efficiency of nearly 100%, and the external quantum efficiency of such TADF-0LED devices can reach or even exceed the level of phosphorescent OLEDs containing precious rare metals.

[0052] The third aspect of the present invention provides an organic electroluminescent device, comprising a substrate, an anode layer, a cathode layer, and at least one organic functional layer between the anode layer and the cathode layer, wherein the organic functional layer contains the heterocyclic compound based on fluorene and carbazole / acridine as described in the first aspect, preferably contains at least one of compounds M1 to M116.

[0053] Preferably, the organic functional layer comprises an organic light-emitting layer, and the organic light-emitting layer contains the heterocyclic compound based on fluorene and carbazole / acridine described in the first aspect.

[0054] Further preferably, the host material and / or guest material of the organic light-emitting layer contains the heterocyclic compound based on fluorene and carbazole / acridine described in the first aspect, preferably contains at least one of compounds M1 to M116.

[0055] Preferably, the organic functional layer further includes at least one of a hole injection layer, a hole transport layer, an electron transport layer or an electron injection layer.

[0056] In the present invention, the organic electroluminescent device includes a substrate, an anode layer, a cathode layer, and a hole injection layer, a hole transport layer, an organic light-emitting layer, an electron transport layer and an electron injection layer between the anode layer and the cathode layer. The hole injection layer, the hole transport layer, the organic light-emitting layer, the electron transport layer and the electron injection layer are sequentially formed on the anode layer.

[0057] The organic electroluminescent device of the present invention can improve the brightness and luminous efficiency of the device and reduce efficiency roll-off based on the excellent performance of the compound of the present invention.

[0058] The light-emitting layer of the organic electroluminescent device of the present invention comprises a host material and a dye. The compound of the present invention can be used as a host material or as a dye.

[0059] The organic electroluminescent device of the present invention comprises a substrate, and an anode layer, a plurality of light-emitting functional layers and a cathode layer sequentially formed on the substrate;

[0060] The light-emitting functional layer includes a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer. The hole injection layer is formed on the anode layer, the hole transport layer is formed on the hole injection layer, the cathode layer is formed on the electron transport layer, and the light-emitting layer is between the hole transport layer and the electron transport layer; the light-emitting layer is the light-emitting layer of the organic electroluminescent device of the present invention.

[0061] Specifically, the anode material can be indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO 2), zinc oxide (ZnO) and other transparent conductive materials, it can also be metal materials such as silver and its alloys, aluminum and its alloys, it can also be organic conductive materials such as PEDOT, and multilayer structures of the above materials.

[0062] The hole injection layer material may include at least one of compounds HI-1 to HI-5:

[0063]

[0064] The hole transport layer material may include at least one of compounds HT-1 to HT-48:

[0065]

[0066]

[0067] The host material may include at least one of compounds H1-1 to H1-93:

[0068]

[0069]

[0070]

[0071]

[0072] The fluorescent dye may include at least one of the following compounds TDE-1 to TDE-31:

[0073]

[0074]

[0075] The electron transport layer material may include at least one of the following compounds ET-1 to ET-45:

[0076]

[0077]

[0078]

[0079] The device may also include an electron injection layer located between the electron transport layer and the cathode. The electron injection layer material includes, but is not limited to, one or more combinations of the following:

[0080] LiQ,LiF,NaCl,CsF,Li 2 O,Cs 2 CO 3,BaO,Na,Li,Ca.

[0081] The cathode is a metal such as a magnesium-silver mixture, LiF / Al, ITO, a metal mixture, or an oxide.

[0082] The synthesis method of the compound of the present invention is briefly described below.

[0083] Representative synthetic routes:

[0084] Synthesis route 1:

[0085]

[0086] Synthesis Path 2:

[0087]

[0088] Among them, A 1 , A 2 , R 10 , R 11 , R 10 '、R 11 ' has the same definition as above. Unless otherwise specified, the raw materials and intermediates used in the synthesis method of the present invention are raw materials obtained through commercial channels. The solvents and reagents used in the present invention, such as dichloromethane, petroleum ether, ethanol, toluene, N, N-dimethylacetamide, 1,4-dioxane and other chemical reagents, can be purchased from the domestic chemical product market, such as Sinopharm Group Reagent Company, TCI Company, Shanghai Bid Pharmaceutical Company, Bailingwei Reagent Company, etc. In addition, those skilled in the art can also synthesize by known methods.

[0089] The analysis and detection of the intermediates and compounds in the present invention were performed using an ABSCIEX mass spectrometer (4000QTRAP) and a Thermo Fisher organic element analyzer.

[0090] The above two synthetic routes are specifically described below in conjunction with Synthesis Examples 1 to 10.

[0091] Example 1: Synthesis of Compound M1

[0092]

[0093] Synthesis of intermediate Ml-1: Take a dried 100 ml three-necked flask, under nitrogen protection, add 4.33 g (10 mmol) 9,9-bis (4-bromophenyl) -9H-fluorene and 3.93 g (25 mmol) o-bromoaniline dissolved in 50 ml toluene, then add 1.44 g (15 mmol) sodium tert-butoxide, 91.54 mg (0.1 mmol) Pd 2 (dba) 3, 16.59mg (0.2mmol) DPPF, replace nitrogen three times and protect, heat and reflux for 4h, TLC (DCM / PE=1 / 30) monitoring: raw material A1 is completely reacted, stop the reaction. After the system cools to room temperature, dichloromethane is extracted, washed with deionized water, the organic phase is combined and concentrated, and then separated by silica gel column chromatography, petroleum ether: dichloromethane=1:1 for elution, the eluent is concentrated and washed with ethanol, and 4.8g of white solid is obtained, with a yield of 82.1%. The molecular ion mass determined by mass spectrometry is: 585.43 (calculated value: 585.57); theoretical element content (%) C 37 H 26 Cl 2 N 2 : C, 78.03; H, 4.60; Cl, ​​12.45; N, 4.92. Measured element content (%): C, 78.08; H, 4.52; Cl, ​​12.44; N, 4.96. The above analysis results show that the obtained product is the expected product M1-1.

[0094] Synthesis of intermediate M1-2: Take a dried 100mL three-necked flask, add 117.8mg (0.52mmol) palladium acetate and 298.8mg (1.03mmol) tri-tert-butylphosphine tetrafluoroborate and dissolve in 50mL N, N-dimethylacetamide, replace with nitrogen three times and protect, stir at room temperature for 0.5h. Then add 3.0g (5.12mmol) M1-1 and 1.42g (10.25mmol) potassium carbonate to the system, replace nitrogen three times and protect, heat to 150℃, and react for 4h. After the reaction is completed, wait for the system to cool to room temperature, filter with silica gel, remove catalyst and inorganic salts, add 15mL dichloromethane and dissolve after concentration, add 100mL ethanol, precipitate, and stir for 1h. Filter to obtain 2.3g brown solid with a yield of 87.4%. The molecular ion mass determined by mass spectrometry is: 496.33 (calculated value: 496.19); theoretical element content (%) C 37 H 24 N 2 : C, 89.49; H, 4.87; N, 5.64. Measured element content (%): C, 89.52; H, 4.88; N, 5.60. The above analysis results show that the obtained product is the expected product M1-2.

[0095] Synthesis of intermediate M1-3: Take a dried 100mL three-necked flask, add 2.68g (10.0mmol) 2-chloro-4,6-diphenyl-1,3,5-triazine, 1.98g (12mmol) 5-nitrile-2-fluorophenylboric acid, 50mL 1,4-dioxane in sequence, and start stirring. Dissolve 2.76g (20.0mmol) potassium carbonate in 10mL deionized water and add it to the system. Add 231mg (0.2mmol) tetrakis (triphenylphosphine) palladium, replace with nitrogen three times and protect, heat to 90℃ and react for 8h. After the reaction is completed, the system is cooled to room temperature, extracted with dichloromethane, washed with deionized water, and then separated by silica gel column chromatography, eluted with petroleum ether: dichloromethane = 2:1, and the eluent is concentrated and 10mL tetrahydrofuran is added. After dissolution, 60mL methanol is added, precipitated, and filtered to obtain 3.0g white solid, with a yield of 85%. The molecular ion mass determined by mass spectrometry is: 352.01 (calculated value: 352.11); theoretical element content (%) C 22 H 13 FN 4 : C, 74.99; H, 3.72; F, 5.39, N, 15.90. Measured element content (%): C, 80.02; H, 3.74; F, 5.42N, 15.92. The above analysis results show that the obtained product is the expected product M1-3.

[0096] Synthesis of compound M1: Take a dry 100mL single-mouth bottle, add 1.5g (2.93mmol) M1-2, 2.58g (7.31mmol) M1-3, 2.86g (8.78mmol) cesium carbonate, and then add 50mL dry DMF (N, N-dimethylformamide). After nitrogen replacement three times, heat to 130°C for 10h. After the reaction stops, remove DMF from the reaction system by vacuum distillation to obtain a large amount of brown solid. After the reaction stops, remove DMF from the reaction system by vacuum distillation to obtain a large amount of brown solid. The crude product was dissolved in 300mL of dichloromethane, washed with a large amount of water, combined with the organic phase and dried with anhydrous magnesium sulfate, concentrated and separated by silica gel column chromatography, eluted with petroleum ether: dichloromethane volume ratio = 5:1, and the eluent was concentrated to obtain 3.0g of light green solid, with a yield of 87%. The molecular ion mass determined by mass spectrometry is: 1176.33 (calculated value: 1176.44); theoretical element content (%) C 8 H 48 N 10 : C, 83.77; H, 4.17; N, 12.06. Measured element content (%): C, 83.76; H, 4.13; N, 12.11. The above analysis results show that the obtained product is the expected product M1.

[0097] Synthesis Example 2: Synthesis of Compound M2: The synthesis method of Compound M1 was adopted, except that 5-nitrile-2-fluorophenylboronic acid was replaced with an equivalent amount of 2-methyl-5-cyanophenylboronic acid to obtain 3.2 g of white solid with a yield of 83%. The molecular ion mass determined by mass spectrometry was: 1188.32 (calculated value: 1188.44); Theoretical element content (%) C 83 H 52 N 10 : C, 83.82; H, 4.41; N, 11.78. Measured element content (%): C, 87.69; H, 4.49; N, 11.83. The above analysis results show that the obtained product is the expected product M2.

[0098] Synthesis Example 3: Synthesis of Compound M3: The synthesis method of Compound M1 was adopted, except that 5-nitrile-2-fluorophenylboronic acid was replaced with an equivalent amount of 2-tert-butyl-5-cyanophenylboronic acid to obtain 3.5 g of white solid with a yield of 85%. The molecular ion mass determined by mass spectrometry was: 1272.43 (calculated value: 1272.53); Theoretical element content (%) C 89 H 64 N 10 : C, 83.94; H, 5.07; N, 11.0. Measured element content (%): C, 83.80; H, 5.14; N, 11.07. The above analysis results show that the obtained product is the expected product M3.

[0099] Synthesis Example 4: Synthesis of Compound M13: The synthesis method of Compound M1 was used, except that 9,9-bis(4-bromophenyl)-9H-fluorene was replaced with an equivalent amount of 3,3-di-tert-butyl-9,9-bis(4-bromophenyl)-9H-fluorene to obtain 3.8 g of a white solid with a yield of 88%. The molecular ion mass determined by mass spectrometry was: 1272.43 (calculated value: 1272.53); Theoretical element content (%) C 89 H 64 N 10 : C, 83.94; H, 5.07; N, 11.0. Measured element content (%): C, 83.83; H, 5.11; N, 11.07. The above analysis results show that the obtained product is the expected product M13.

[0100] Synthesis Example 5: Synthesis of Compound M23: The synthesis method of Compound M1 was used, except that 9,9-bis(4-bromophenyl)-9H-fluorene was replaced with an equivalent amount of 3,3-diphenyl-9,9-bis(4-bromophenyl)-9H-fluorene, and 5-nitrile-2-fluorophenylboronic acid was replaced with an equivalent amount of 2-phenyl-5-cyanophenylboronic acid to obtain 4.1 g of a white solid with a yield of 79%. The molecular ion mass determined by mass spectrometry was: 1424.78 (calculated value: 1424.59); Theoretical element content (%) C 101 H 72 N 10 : C, 85.09; H, 5.09; N, 9.82. Measured element content (%): C, 85.20; H, 5.01; N, 11.79. The above analysis results show that the obtained product is the expected product M23.

[0101] Synthesis Example 6: Synthesis of Compound M37: The synthesis method of Compound M1 was used, except that 5-nitrile-2-fluorophenylboronic acid was replaced with an equivalent amount of 5-trifluoromethyl-2-fluorophenylboronic acid to obtain 3.3 g of a white solid with a yield of 86%. The molecular ion mass determined by mass spectrometry was: 1246.44 (calculated value: 1246.39); Theoretical element content (%) C 81 H 48 F 6 N 8 : C, 78.0; H, 3.88; F: 9.14, N, 8.98. Measured element content (%): C, 78.05; H, 3.83; F: 9.14, N, 8.99. The above analysis results show that the obtained product is the expected product M37.

[0102] Synthesis Example 7: Synthesis of Compound M73:

[0103]

[0104] Synthesis of intermediate M73-1: Take a dried 100ml three-necked flask, under nitrogen protection, add 7.14g (15mmol) 9,9-bis (4-bromophenyl) -9H-fluorene and 4.99g (33mmol) methyl anthranilate dissolved in 50ml toluene, add 9.77g (30mmol) cesium carbonate, 67.3mg (0.3mmol) palladium acetate, 34.7mg (0.06mmol) XantPhos, replace nitrogen three times and protect, react at 100°C for 12h. After the reaction is completed, after the system is cooled to room temperature, dichloromethane is extracted, washed with deionized water, the organic phase is combined and concentrated, and then separated by silica gel column chromatography, petroleum ether: dichloromethane = 4:1 for elution, and dichloromethane and methanol are recrystallized after concentration to obtain 8.2g of brown solid, with a yield of 88.6%. The molecular ion mass determined by mass spectrometry is: 616.30 (calculated value: 616.24); theoretical element content (%) C 41 H 32 N 2 O 4 : C, 79.85; H, 5.23; N, 4.54; O, 10.38. Measured element content (%): C, 79.91; H, 5.20; N, 4.53; O, 10.37. The above analysis results show that the obtained product is the expected intermediate M73-1.

[0105] Synthesis of intermediate M73-2: Take a dry single-mouth bottle and mix 8.0 g (12.97 mmol) of intermediate M73-1, 7.73 g (64.86 mmol) of CH 3 MgBr was dissolved in tetrahydrofuran and reacted at 25°C for 12 hours. After the reaction, the system was cooled to room temperature and extracted with dichloromethane, washed with deionized water, and the organic phase was combined and concentrated. Then, silica gel column chromatography was performed and eluted with petroleum ether: dichloromethane volume ratio = 4:1. After concentration, dichloromethane and methanol were recrystallized to obtain 6g of brown solid with a yield of 75%. The molecular ion mass determined by mass spectrometry was: 616.20 (calculated value: 616.31); theoretical element content (%) C 43 H 40 N 2 O 2 : C, 83.73; H, 6.54; N, 4.54; O, 5.19. Measured element content (%): C, 83.66; H, 6.56; N, 4.56; O, 5.22. The above analysis results show that the obtained product is the expected intermediate M73-2.

[0106] Synthesis of intermediate M73-3: Take a dry single-mouth bottle, dissolve 6.0g (9.73mmol) of intermediate M73-2 in a mixture of 15mL hydrochloric acid and 75mL acetic acid, react at 120℃ for 12h, and after the reaction is completed, extract with dichloromethane after the system cools to room temperature, wash with deionized water, combine the organic phases and concentrate, and then separate by silica gel column chromatography, eluting with petroleum ether: dichloromethane volume ratio = 4:1, and recrystallize with dichloromethane and methanol after concentration to obtain 4.7g of brown solid, with a yield of 78%. The molecular ion mass determined by mass spectrometry is: 580.12 (calculated value: 580.29); theoretical element content (%) C 43 H 36 N 2 : C, 88.93; H, 6.25; N, 4.82. Measured element content (%): C, 88.80; H, 6.30; N, 4.90. The above analysis results show that the obtained product is the expected intermediate M73-3.

[0107] Synthesis of M73: After obtaining M73-3, the other steps are the same as the synthesis method of M1. 4.2 g of yellow-green solid is obtained, with a yield of 79%. The molecular ion mass determined by mass spectrometry is: 580.12 (calculated value: 580.29); theoretical element content (%) C 43 H 36 N 2 : C, 88.93; H, 6.25; N, 4.82. Measured element content (%): C, 88.80; H, 6.30; N, 4.90. The above analysis results show that the obtained product is the expected product M73.

[0108] Synthesis Example 7: Synthesis of Compound M81: The synthesis method of Compound M73 was used, except that 9,9-bis(4-bromophenyl)-9H-fluorene was replaced by an equivalent amount of 3,3-dimethyl-9,9-bis(4-bromophenyl)-9H-fluorene, and CH 3 MgBr is replaced by an equivalent of CH 3 CH 2 MgBr, 4.6 g of yellow-green solid was obtained, with a yield of 78%. The molecular ion mass determined by mass spectrometry was: 1328.46 (calculated value: 1328.59); theoretical element content (%) C 93 H 72 N 10 : C, 84.01; H, 5.46; N, 10.53. Measured element content (%): C, 84.21; H, 5.40; N, 10.39. The above analysis results show that the obtained product is the expected product M81.

[0109] Synthesis Example 8: Synthesis of Compound M87: The synthesis method of Compound M73 was used, except that 9,9-bis(4-bromophenyl)-9H-fluorene was replaced with an equivalent amount of 3,3-di-tert-butyl-9,9-bis(4-bromophenyl)-9H-fluorene, and CH 3 MgBr is replaced by an equivalent amount of C 6 H 6 MgBr, 5.3 g of yellow-green solid was obtained, with a yield of 76%. The molecular ion mass determined by mass spectrometry was: 1604.45 (calculated value: 1604.49); theoretical element content (%) C 107 H 68 N 10 : C, 86.03; H, 4.59; N, 9.38. Measured element content (%): C, 86.14; H, 5.56; N, 9.31. The above analysis results show that the obtained product is the expected product M81.

[0110] Synthesis Example 9: Synthesis of Compound M105: The synthesis method of Compound M73 was used, except that 9,9-bis(4-bromophenyl)-9H-fluorene was replaced by an equivalent amount of 3,3-diphenyl-9,9-bis(4-bromophenyl)-9H-fluorene, and CH 3 MgBr is replaced by an equivalent of CH 3 CH 2 MgBr, 5-nitrile-2-fluorophenylboronic acid was replaced with an equivalent amount of 5-trifluoromethyl-2-fluorophenylboronic acid to obtain 6.0 g of yellow-green solid with a yield of 73%. The molecular ion mass determined by mass spectrometry was: 1538.55 (calculated value: 1538.61); Theoretical element content (%) C 103 H 76 F 6 N 8 : C, 80.34; H, 4.98; F: 7.40; N, 7.28. Measured element content (%): C, 80.18; H, 5.06; F, 7.41N, 7.35. The above analysis results show that the obtained product is the expected product M105.

[0111] Synthesis Example 10: Synthesis of Compound M116: The synthesis method of Compound M73 was used, except that 9,9-bis(4-bromophenyl)-9H-fluorene was replaced by an equivalent amount of 3,3-diphenyl-9,9-bis(4-bromophenyl)-9H-fluorene, and CH 3 MgBr is replaced by an equivalent of CH 3 C 6 H 4MgBr, 5-nitrile-2-fluorophenylboronic acid was replaced with an equivalent amount of 5-trifluoromethyl-2-fluorophenylboronic acid to obtain 6.2 g of yellow-green solid with a yield of 70%. The molecular ion mass determined by mass spectrometry was: 1787.02 (calculated value: 1786.67); Theoretical element content (%) C 123 H 84 F 6 N 8 : C, 82.62; H, 4.74; F: 6.38; N, 6.27. Measured element content (%): C, 82.68; H, 4.72; F, 6.36N, 6.25. The above analysis results show that the obtained product is the expected product M116.

[0112] The light-emitting layer of the organic electroluminescent device and the organic electroluminescent device of the present invention are described below.

[0113] Device Example 1: Compound M1 of the present invention is used as the host material of a thermally activated delayed fluorescence (TADF) organic electroluminescent device.

[0114] The device structure is shown below:

[0115] ITO(150nm) / HI-1(10nm) / HT-2(40nm) / M1:TDE-3(30nm, 5%wt) / ET-4(25nm) / LiF(0.5nm) / Al(150nm).

[0116] The organic electroluminescent device was prepared as follows: a glass plate coated with a transparent conductive layer of ITO (thickness 150 nm) was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone:ethanol, baked in a clean environment until the water was completely removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam;

[0117] Place the glass substrate with the anode in a vacuum chamber and evacuate to 1×10 -5 ~1×10 -4 Pa, HI-1 and HT-2 were vacuum evaporated on the above anode layer as hole injection layer and hole transport layer, respectively, the evaporation rate was 0.1nm / s, and the evaporation film thickness was 10nm and 40nm respectively;

[0118] "Ml:TDE-3 (30nm, 5%wt)" is vacuum evaporated on the hole transport layer as the light-emitting layer of the organic electroluminescent device. The evaporation rate is 0.lnm / s and the total film thickness of the evaporation is 30nm; wherein "5%wt" refers to the doping ratio of the dye, that is, the weight ratio of the main material to TDE-3 is 95:5.

[0119] ET-4 was vacuum-deposited on the light-emitting layer as the electron transport layer of the organic electroluminescent device, with a deposition rate of 0.1 nm / s and a total film thickness of 20 nm;

[0120] 0.5 nm of LiF as an electron injection layer and 150 nm of Al as a cathode were vacuum-deposited on the electron transport layer.

[0121] Device Example 2-4: Compounds M16, M29 and M66 of the present invention are used as the main materials of thermally activated delayed fluorescence organic electroluminescent devices.

[0122] The method of device embodiment 1 is adopted, except that the main material compound M1 is replaced by M16, M29, and M66.

[0123] Device Comparative Examples 1-3: Using other compounds as the main material of the thermally activated delayed fluorescence organic electroluminescent device.

[0124] The method of device embodiment 1 is adopted, except that the host material compound M1 is replaced by compounds H1-3, H1-13 and H1-25 respectively.

[0125] Device Example 5: Compound M1 of the present invention is used as the main material of a thermally activated delayed fluorescence organic electroluminescent device.

[0126] The method of device embodiment 1 is adopted, except that the electron transport material is replaced by ET-6 from ET-4, the dye is replaced by TDE-5 from TDE-3, and the main material is still M1.

[0127] Device Comparative Examples 4-5: Other compounds are used as the main material of the thermally activated delayed fluorescence organic electroluminescent device.

[0128] The method of device embodiment 5 is adopted, except that the host material compound M1 is replaced by compounds H1-36 and H1-44 respectively.

[0129] Device Examples 6-8: Compounds M76, M89 and M112 of the present invention are used as the main materials of thermally activated delayed fluorescence organic electroluminescent devices.

[0130] The method of device embodiment 5 is adopted, except that the main material compound M76 is replaced by compounds M76, M89, and M112 respectively.

[0131] Device Example 9: The compound M112 of the present invention is used as the main material of a thermally activated delayed fluorescence organic electroluminescent device.

[0132] The method of device embodiment 8 is adopted, except that the electron transport material is replaced by ET-18 from ET-6, the dye is replaced by TDE-10 from TDE-5, and the main material is still M112.

[0133] Device Comparative Examples 6-7: Other compounds are used as the main material of the thermally activated delayed fluorescence organic electroluminescent device.

[0134] The method of device embodiment 9 is adopted, except that the host material compound M112 is replaced by compounds H1-56 and H1-72.

[0135] The organic electroluminescent devices prepared by the above process were subjected to the following performance tests: Under the same brightness, the turn-on voltage, maximum external quantum efficiency and efficiency roll-off at 1000 nit of the organic electroluminescent devices prepared in device examples 1 to 9 and device comparison examples 1 to 8 were measured using a digital source meter and a brightness meter. Specifically, the voltage was increased at a rate of 0.1 V per second, and the brightness of the organic electroluminescent device was measured when it reached lcd / m 2 The voltage at this time is the turn-on voltage, and the current density at this time is measured and the maximum external quantum efficiency is calculated based on the spectrum and other data; the test results are listed in Table 1.

[0136] Table 1

[0137]

[0138] It can be seen from the above table that when the compound of the present invention is used as the main body of the TADF type dye, its turn-on voltage, maximum external quantum efficiency and efficiency roll-off are all improved, showing excellent device performance.

[0139] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the heterocyclic compounds based on fluorene and carbazole / acridine and their applications in organic electroluminescent devices, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A heterocyclic compound based on fluorene and carbazole / acridine, characterized in that: The compound has a structure shown in the following formula (1): wherein n is 0 or 1; R is selected from at least one of a C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group; A 1 and A 2 Each independently selects at least one of a cyano group and a trifluoromethyl group; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 1 '、R 2 '、R 3 '、R 4 '、R 5 '、R 6 '、R 7 '、R 8 ' and R 9 'Each independently selects hydrogen atoms, C1~C 10 Alkyl, substituted or unsubstituted C6~C 30 Aryl and substituted or unsubstituted C3~C 30 At least one of heteroaryl groups.

2. The heterocyclic compound based on fluorene and carbazole / acridine according to claim 1, characterized in that: The heterocyclic compound based on fluorene and carbazole / acridine has any one of the general formula (II-1) or general formula (II-2): In the general formula (II-1) and the general formula (II-2), A 1 , A 2 , R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 1 '、R 2 '、R 3 '、R 4 '、R 5 '、R 6 '、R 7 '、R 8 ' and R 9 ' has the same meaning as in claim 1. In the general formula (II-2), R 10 , R 11 , R 10 '、R 11 'Each independently select at least one of a C1-C10 alkyl group, a substituted or unsubstituted C6-C30 aryl group, and a substituted or unsubstituted C3-C30 heteroaryl group.

3. The heterocyclic compound based on fluorene and carbazole / acridine according to claim 1 or 2, characterized in that: C1~C 10 The alkyl group is selected from at least one of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; Preferably, the substituted or unsubstituted C6~C 30 The aryl group is selected from at least one of substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted anthracenyl, substituted or unsubstituted phenanthryl, substituted or unsubstituted indenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted benzofluorenyl, substituted or unsubstituted 9,9'-dialkylfluorenyl, substituted or unsubstituted 9,9-spirobifluorenyl, substituted or unsubstituted indenofluorenyl, substituted or unsubstituted fluoranthenyl, substituted or unsubstituted triphenylene, substituted or unsubstituted pyrenyl, substituted or unsubstituted peryl, substituted or unsubstituted cyanocyanol and substituted or unsubstituted tetraphenylcyanocyanol; Preferably, the substituted or unsubstituted C1 to C 30 The heteroaryl group is selected from at least one of a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzoselenophene group, a substituted or unsubstituted dibenzofuranyl group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted azacarbazolyl group, and a substituted or unsubstituted benzocarbazolyl group; Preferably, the substituent in the substituted group is selected from one of methyl, tert-butyl, phenyl or carbazole.

4. The heterocyclic compound based on fluorene and carbazole / acridine according to any one of claims 1 to 3, characterized in that: The C1-C10 alkyl group is at least one selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl and n-decyl; preferably, the alkyl group is methyl, ethyl or tert-butyl. Preferably, the substituted or unsubstituted C6-C30 aryl group is selected from substituted or unsubstituted phenyl groups; the substituent in the substituted phenyl group is preferably methyl, tert-butyl, or phenyl; Preferably, the substituted or unsubstituted C1-C30 heteroaryl group is selected from substituted or unsubstituted carbazolyl groups, and the substituent in the substituted carbazolyl group is selected from one of methyl, tert-butyl or phenyl groups.

5. The heterocyclic compound based on fluorene and carbazole / acridine according to any one of claims 1 to 4, characterized in that: The heterocyclic compound based on fluorene and carbazole / acridine is a symmetrical structure, wherein A 1 and A 2 Same, R 1 With R 1 'Same, R 2 With R 2 'Same, R 3 With R 3 'Same, R 4 With R 4 'Same, R 5 With R 5 'Same, R 6 With R 6 'Same, R 7 With R 7 'Same, R 8 With R 8 'Same, R 9 With R 9 'Same, R 10 With R 10 'Same, R 11 With R 11 'same.

6. The heterocyclic compound based on fluorene and carbazole / acridine according to any one of claims 1 to 5, characterized in that: The heterocyclic compound based on fluorene and carbazole / acridine is selected from any one of the following compounds:

7. Use of the heterocyclic compound based on fluorene and carbazole / acridine according to any one of claims 1 to 6 in the preparation of an organic electroluminescent device.

8. The use according to claim 7, wherein the heterocyclic compound based on fluorene and carbazole / acridine is used as a host material and / or a guest material of the light-emitting layer of the organic electroluminescent device.

9. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises a substrate, an anode layer, a cathode layer, and at least one organic functional layer between the anode layer and the cathode layer, wherein the organic functional layer contains the heterocyclic compound based on fluorene and carbazole / acridine according to any one of claims 1 to 6.

10. The organic electroluminescent device according to claim 9, characterized in that: The organic functional layer comprises an organic light-emitting layer, wherein the host material and / or the guest material of the organic light-emitting layer comprises the heterocyclic compound based on fluorene and carbazole / acridine according to any one of claims 1 to 6; Preferably, the organic functional layer further includes at least one of a hole injection layer, a hole transport layer, an electron transport layer or an electron injection layer.

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