Thermally activated delayed fluorescence material, organic electroluminescent device and application thereof

Abstract

The application relates to the technical field of organic electroluminescence, in particular to an organic compound and application thereof, the compound has the structure shown in the following formula (1), D1 is selected from the structure represented by formula (I), and D2 is selected from the structure represented by general formula (II). When the compound is used as an OLED device, the device efficiency can be effectively improved, the driving voltage is reduced, and the compound is a luminescent material with good performance.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials technology, specifically to a compound, a thermally activated delayed fluorescence material, an organic electronic light-emitting device containing the same, and their applications. Background Technology

[0002] Under electroexcitation conditions, organic electroluminescent devices generate 25% singlet excitons and 75% triplet excitons. Traditional fluorescent materials, due to spin-forbidden conditions, can only utilize 25% of the singlet excitons, thus limiting their external quantum efficiency to less than 5%. Almost all triplet excitons are lost thermally. To improve the efficiency of organic electroluminescent devices, it is essential to fully utilize triplet excitons.

[0003] To address this, researchers have proposed numerous methods, the most significant being the utilization of phosphorescent materials. Phosphorescent materials, due to the introduction of heavy atoms, exhibit a spin-orbit coupling effect, allowing full utilization of 75% of triplet excitons to achieve 100% internal quantum efficiency. However, the use of rare heavy metals in phosphorescent materials makes them expensive, hindering cost control. If fluorescent devices could effectively utilize triplet excitons, this problem could be significantly solved. Researchers have proposed a method to improve the efficiency of fluorescent devices by using triplet exciton quenching to generate singlet excitons, but the theoretically achievable maximum external quantum efficiency is only 62.5%, far lower than that of phosphorescent materials. Therefore, finding new technologies to fully utilize the triplet energy levels of fluorescent materials to improve luminescence efficiency is essential. Summary of the Invention

[0004] The main objective of this invention is to provide a compound, a thermally activated delayed fluorescence material, an organic electronic light-emitting device containing the same, and its applications, in order to solve the aforementioned technical problems.

[0005] This invention discloses a compound whose structure is represented by general formula (1):

[0006]

[0007] In equation (1):

[0008] R 1It is selected from one or a combination of at least two of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl.

[0009] D1 is selected from the structure represented by equation (Ⅰ):

[0010]

[0011] Among them, Ar 1 and Ar 2 Ar is independently selected from substituted or unsubstituted C6–C30 aryl groups and substituted or unsubstituted C3–C30 heteroaryl groups. 1 and Ar 2 They can be linked into a ring or not; * indicates the linking site of the group;

[0012] D2 is selected from the structure represented by general formula (II):

[0013]

[0014] Where A represents the structure represented by formula (a1), and the dashed line indicates the fusion position of the group;

[0015] R 2 R 3 R 4 R 5 Each of the following is independently selected from substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl;

[0016] b is selected from integers from 0 to 4; c is selected from integers from 0 to 2; d is selected from integers from 0 to 4; e is selected from integers from 0 to 8;

[0017] m and n are each independently selected from integers from 1 to 4, a is selected from integers from 0 to 3, and m+n+a is less than or equal to 5; preferably a is 0;

[0018] When the above-mentioned groups contain substituents, the substituents are selected from one or a combination of at least two of the following: halogen, cyano, nitro, hydroxyl, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C12 alkoxy, C1-C12 thioalkoxy, C1-C12 silyl, amino, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aryl, C10-C30 fused-ring aryl, C3-C30 monocyclic heteroaryl, and C6-C30 fused-ring heteroaryl.

[0019] More preferably, the general formula compound of the present invention is shown in formula (2-1) or (2-2):

[0020]

[0021] In equation (2-1) or (2-2), D1, D2, and R 1 The definitions are the same as those in general formula (1);

[0022] D1' and D1" may be the same or different, and are independently selected from formula (I); D2' and D2" may be the same or different, and are independently selected from general formula (II); the definitions of formula (I) and formula (II) are the same as those in claim 1.

[0023] n' is selected from an integer from 1 to 3, a' is selected from an integer from 0 to 2, and n'+a' is less than or equal to 3; preferably a' is 0;

[0024] m' is selected from an integer from 1 to 3, a” is selected from an integer from 0 to 2, and m'+a” is less than or equal to 3; preferably a” is 0;

[0025] Preferably, in equation (2-1), n' is 1;

[0026] Preferably, in equation (2-2), m' is 1.

[0027] More preferably, the general formula compound of the present invention is shown in formula (2-1).

[0028] Furthermore, the general formula compound of the present invention is shown in formula (3-1) or (3-2):

[0029]

[0030] In equation (3-1) or (3-2), D1, D2, and R 1The definitions of D1', D1”, D2', D2”, a' and a” are the same as those in general formula (1); the definitions of D1', D1”, D2', D2”, a' and a” are the same as those in formulas (2-1) and (2-2).

[0031] More preferably, the general formula compound of the present invention is shown in formula (3-1).

[0032] Preferably, D1, D1', and D1" are each independently selected from the structures represented by formula (Ⅰ-1) or formula (Ⅰ-2):

[0033]

[0034] In equation (Ⅰ-1), X 1 -X 10 Selected independently from CR 9 Or N,R 9 Independently selected from one or a combination of at least two of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxy, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl, and X 1 -X 5 Zhong, X 6 -X 10 Any two adjacent elements in a circle can be connected to form a ring;

[0035] In equation (Ⅰ-2), X 11 -X 18 Selected independently from CR 12 Or N,R 12 Independently selected from one or a combination of at least two of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxy, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl, and X 11 -X 14 Zhong, X15 -X 18 Any two adjacent elements in a loop can be connected to form a ring.

[0036] More preferably, D1, D1', and D1" are each independently selected from any one of the following groups:

[0037]

[0038] More preferably, D2, D2', and D2" are each independently selected from any one of the following groups:

[0039]

[0040] Among them, R 2 R 3 R 4 R 5 The definitions of a, b, d, c and e are the same as those in equation (II).

[0041] Preferably, the R 2 R 3 R 4 R 5 Independently selected from one of the following groups, whether substituted or unsubstituted:

[0042]

[0043] Preferably, in formulas (1), (2-1), (2-2), (3-1), or (3-2), D2, D2', and D2" are each independently selected from any one of the following groups:

[0044]

[0045] In a further preferred embodiment, R in the above general formula 1 Selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, cyclopentyl, cyclohexyl, or selected from the following substituted or unsubstituted groups: phenyl, biphenyl, terphenyl, naphthyl, anthracene, phenanthryl, indene, fluorene, 9,9'-dimethylfluorene, 9,9'-spirodifluorene, benzo[a]fluorene, fluoranyl, triphenylene, pyrene, perylene, One of the following: benzofuranyl, benzothiophenyl, furanyl, thiophenyl, pyrroleyl, benzofuranyl, benzothiophenyl, isobenzofuranyl, indolyl, dibenzofuranyl, dibenzothiophenyl, and carbazoyl.

[0046] The above-mentioned "substituted or unsubstituted" group may be substituted with one substituent or multiple substituents. When there are multiple substituents, they may be selected from different substituents. When the same expression is involved in the present invention, it has the same meaning, and the selection range of the substituents is as shown above and will not be elaborated one by one.

[0047] In this specification, the expression of Ca~Cb represents that the group has a carbon atom number of a~b. Generally, unless otherwise specified, the carbon atom number does not include the carbon atom number of the substituent.

[0048] In this specification, the expression of a ring structure crossed by "—" indicates that the bonding site is at any position on the ring structure where bonding can occur.

[0049] In this specification, the substituted or unsubstituted C6~C30 aryl group is preferably a C6~C20 aryl group, more preferably a group selected from the group consisting of phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, indenyl, fluorenyl and its derivatives, fluoranthenyl, triphenylene, pyrenyl, perylenyl, and naphthacenyl. Specifically, the biphenyl is selected from 2-biphenyl, 3-biphenyl and 4-biphenyl; the terphenyl includes p-terphenyl-4-yl, p-terphenyl-3-yl, p-terphenyl-2-yl, m-terphenyl-4-yl, m-terphenyl-3-yl and m-terphenyl-2-yl; the naphthyl includes 1-naphthyl and 2-naphthyl; the anthryl is selected from 1-anthryl, 2-anthryl and 9-anthryl; the fluorenyl is selected from 1-fluorenyl, 2-fluorenyl, 3-fluorenyl, 4-fluorenyl and 9-fluorenyl; the fluorenyl derivatives are selected from 9,9'-dimethylfluorene, 9,9'-spirobifluorene and benzofluoren; the pyrenyl is selected from 1-pyrenyl, 2-pyrenyl and 4-pyrenyl; the naphthacenyl is selected from 1-naphthacenyl, 2-naphthacenyl and 9-naphthacenyl.

[0050] The heteroatoms in the present invention generally refer to atoms or atomic groups selected from N, O, S, P, Si and Se, preferably selected from N, O, S.

[0051] The atomic names described in the present invention include their corresponding various isotopes. For example, hydrogen (H) includes 1 H (protium or also called H), 2 H (deuterium or also called D), etc.; carbon (C) includes 12 C, <00000-40>C, etc.

[0052] In this specification, the substituted or unsubstituted C3-C30 heteroaryl group is preferably a C4-C20 heteroaryl group, more preferably a nitrogen-containing heteroaryl group, an oxygen-containing heteroaryl group, a sulfur-containing heteroaryl group, etc. Specific examples include: furanyl, thiophene, pyrrole, benzofuranyl, benzothiophene, isobenzofuranyl, indolyl, dibenzofuranyl, dibenzothiophene, carbazole and its derivatives, wherein the carbazole derivative is preferably 9-phenylcarbazole, 9-naphthylcarbazole, benzocarbazole, dibenzocarbazole, or indolocarbazole.

[0053] In this specification, the aforementioned C1-C12 chain alkyl group is preferably a C1-C10 chain alkyl group, more preferably a C1-C6 chain alkyl group, such as methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, isopropyl, isobutyl, tert-butyl, etc.

[0054] In this specification, C3-C12 cycloalkyl groups include monocycloalkyl and polycycloalkyl groups, preferably C1-C10 alkyl groups and C3-C10 cycloalkyl groups.

[0055] Furthermore, the general formula compound of the present invention is preferably any one of the structural compounds shown in S1-S155 below:

[0056]

[0057]

[0058]

[0059]

[0060]

[0061] Another objective of this invention is to provide the application of the above-described compounds of this invention in organic electroluminescent devices.

[0062] Preferably, the compounds of the present invention are suitable for use as luminescent dyes and / or sensitizers in the luminescent layer of organic electroluminescent devices. Furthermore, this application is not limited to organic electroluminescent materials, but can also be applied to optical sensors, solar cells, lighting elements, organic thin-film transistors, organic field-effect transistors, organic thin-film solar cells, information tags, electronic artificial skin sheets, sheet-type scanners and other large-area sensors, electronic paper, and other technical fields.

[0063] The present invention also discloses a thermally activated delayed fluorescence material comprising the compounds described above.

[0064] The present invention also discloses the application of the thermally activated delayed fluorescence material as described above in an organic electroluminescent device, preferably as a light-emitting layer in the organic electroluminescent device, and more preferably as a light-emitting dye and / or sensitizer in the light-emitting layer of the organic electroluminescent device.

[0065] The present invention also discloses an organic electroluminescent device, which includes a first electrode, a second electrode, and one or more organic layers inserted between the first electrode and the second electrode, wherein the organic layer contains at least one compound of the present invention as described above. Specifically, the organic layer may include a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, and an electron transport layer, wherein the light-emitting layer contains the general formula compound of the present invention shown in formulas (1), (2-1), (2-2), (3-1), and (3-2).

[0066] The present invention also discloses a display screen or display panel, wherein the display screen or display panel employs the organic electroluminescent device as described above; preferably, the display screen or display panel is an OLED display.

[0067] The present invention also discloses an electronic device having a display screen or display panel, wherein the display screen or display panel employs an organic electroluminescent device as described above.

[0068] The specific reasons for the excellent performance of the compounds of the present invention as luminescent dyes and / or sensitizers in organic electroluminescent devices are not yet clear, but it is speculated that the reasons may be as follows:

[0069] 1. D1 is a donor with a small twist angle and an inert protecting group on the outside. The HOMO and LUMO between the donor and acceptor have a certain overlap, which is beneficial to improving the fluorescence quantum yield.

[0070] 2. D2 uses a carbazole-spirofluorene rigid donor to increase the intermolecular distance. This results in a small singlet-triplet energy level difference in the molecule, which is beneficial for improving the TADF properties.

[0071] 3. With the synergistic effect of the two donors, the TADF material is guaranteed to have a small singlet-triplet energy level difference and a high fluorescence quantum yield, while suppressing Dexter energy transfer. Detailed Implementation

[0072] Specific embodiments of the present invention will now be described in detail. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the embodiments of the invention. In other instances, well-known structures, materials, or methods have not been specifically described to avoid obscuring the embodiments of the invention.

[0073] Throughout this specification, references to "some embodiments," "embodiment," "an example," or "example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "in one embodiment," "in one embodiment," "an example," or "example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0074] The basic concept of this invention is to provide a compound in which a donor with a small twist angle is introduced at the ortho position of the cyano group, so that the HOMO and LUMO between the donor and acceptor overlap to a certain extent, which is beneficial to improving the fluorescence quantum yield; and in which a donor with high rigidity is introduced at the para position of the cyano group, which can increase the intermolecular distance, so that the molecule has a small singlet-triplet energy level difference, improving the TADF property of the molecule; and under the synergistic effect of the two donors, Dexter energy transfer can be suppressed, thereby improving the TADF property and fluorescence quantum yield of the molecule.

[0075] The present invention will be described in detail below with several specific embodiments. The compounds of the present invention can be synthesized with reference to the specific synthesis examples shown below. However, it should be noted that obtaining the compounds is not limited to the synthesis methods and raw materials used in the present invention. Those skilled in the art can also select other methods or routes to obtain the novel compounds proposed in the present invention. The compounds for which synthesis methods are not mentioned in the present invention are all raw material products obtained through commercial means, or self-made using these raw material products according to known methods.

[0076] The solvents and reagents used in the synthesis examples, such as dichloromethane, petroleum ether, ethanol, tetrahydrofuran, N,N-dimethylacetamide, anhydrous magnesium sulfate, carbazole, benzimidazole, etc., can all be purchased from domestic chemical product markets, such as from Sinopharm Reagent Company, TCI Company, Shanghai Bid Pharmaceutical Company, and Bailingwei Reagent Company. Alternatively, those skilled in the art can also synthesize them using well-known methods.

[0077] The analysis and detection of synthetic intermediates and compounds were performed using an ABSCIEX mass spectrometer (4000QTRAP).

[0078] The general formula for synthesis is as follows:

[0079]

[0080] Synthesis Example 1: Synthesis of S1

[0081]

[0082] Synthesis of intermediate S1-1:

[0083] Carbazole and spirofluorene (14.54 g, 35.85 mmol), 2,6-dibromo-4-fluorobenzonitrile (10 g, 35.85 mmol), cesium carbonate (23.36 g, 71.71 mmol), and N,N-dimethylformamide (200 ml) were added to a 500 ml single-necked flask at room temperature. The reaction was carried out overnight at 120 °C under nitrogen protection. Heating was stopped, and after cooling to room temperature, 500 ml of water was added and stirred for 10 min. A large amount of white solid precipitated. The solid was filtered, and the filter cake was washed with ethanol for 2 h. After cooling, the solid was filtered again to obtain 18 g of white solid product, with a yield of 75.6%. The molecular ion mass determined by mass spectrometry was 664.34 (theoretical value: 664.40).

[0084] Synthesis of compound S1:

[0085] At room temperature, S1-1 (5 g, 7.53 mmol), carbazole (2.52 g, 12.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6 g of crude product. Recrystallization from toluene / ethanol gave 4 g of white solid, with a yield of 63.5%. Mass spectrometry analysis determined the molecular ion mass to be 836.89 (theoretical value: 837.00).

[0086] Synthesis Example 2: Synthesis of S2

[0087]

[0088] Synthesis of compound S2:

[0089] At room temperature, S1-1 (5 g, 7.53 mmol), 3,6-dimethylcarbazole (2.94 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 5 g of crude product. Recrystallization from toluene / ethanol gave 4 g of white solid, with a yield of 59.5%. Mass spectrometry analysis determined the molecular ion mass to be 864.44 (theoretical value: 864.33).

[0090] Synthesis Example 3: Synthesis of S4

[0091]

[0092] Synthesis of compound S4:

[0093] At room temperature, S1-1 (5 g, 7.53 mmol), 3-isopropylcarbazole (3.78 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 5.2 g of crude product. Recrystallization from toluene / ethanol gave 4.5 g of white solid, with a yield of 46.7%. Mass spectrometry analysis determined the molecular ion mass to be 920.41 (theoretical value: 920.39).

[0094] Synthesis Example 4: Synthesis of S5

[0095]

[0096] Synthesis of compound S5:

[0097] At room temperature, S1-1 (5 g, 7.53 mmol), 3-tert-butylcarbazole (3.78 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The flask was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6.7 g of crude product. Recrystallization from toluene / ethanol gave 5.5 g of white solid, with a yield of 77%. Mass spectrometry analysis determined the molecular ion mass to be 949.34 (theoretical value: 949.21).

[0098] Synthesis Example 5: Synthesis of S6

[0099]

[0100] Synthesis of compound S6:

[0101] At room temperature, S1-1 (5 g, 7.53 mmol), 3-methoxycarbazole (3.42 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6 g of crude product. Recrystallization from toluene / ethanol gave 5 g of white solid, with a yield of 74.1%. Mass spectrometry analysis determined the molecular ion mass to be 957.01 (theoretical value: 956.34).

[0102] Synthesis Example 6: Synthesis of S7

[0103]

[0104] Synthesis of compound S7:

[0105] At room temperature, S1-1 (5 g, 7.53 mmol), 3,6-dimethylcarbazole (2.94 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6 g of crude product. Recrystallization from toluene / ethanol gave 5 g of white solid, with a yield of 74.4%. Mass spectrometry analysis determined the molecular ion mass to be 892.44 (theoretical value: 892.36).

[0106] Synthesis Example 7: Synthesis of S8

[0107]

[0108] Synthesis of compound S8:

[0109] At room temperature, S1-1 (5 g, 7.53 mmol), 3,6-diethylcarbazole (3.36 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6.7 g of crude product. Recrystallization from toluene / ethanol gave 5.8 g of white solid, with a yield of 81.2%. Mass spectrometry analysis determined the molecular ion mass to be 848.33 (theoretical value: 948.42).

[0110] Synthesis Example 8: Synthesis of S9

[0111]

[0112] Synthesis of compound S9:

[0113] At room temperature, S1-1 (5 g, 7.53 mmol), 3,6-diisopropylcarbazole (3.78 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The flask was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 7 g of crude product. Recrystallization from toluene / ethanol gave 6 g of white solid, with a yield of 79.3%. Mass spectrometry analysis determined the molecular ion mass to be 1004.52 (theoretical value: 1004.48).

[0114] Synthesis Example 9: Synthesis of S10

[0115]

[0116] Synthesis of compound S10:

[0117] At room temperature, S1-1 (5 g, 7.53 mmol), 3,6-di-tert-butylcarbazole (4.21 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The flask was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 7.5 g of crude product. Recrystallization from toluene / ethanol gave 6.6 g of white solid, with a yield of 82.6%. Mass spectrometry analysis determined the molecular ion mass to be 1060.66 (theoretical value: 1060.54).

[0118] Synthesis Example 10: Synthesis of S26

[0119]

[0120] Synthesis of compound S26:

[0121] At room temperature, S1-1 (5 g, 7.53 mmol), diphenylamine (2.55 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 5 g of crude product. Recrystallization from toluene / ethanol gave 4 g of white solid, with a yield of 63.2%. Mass spectrometry analysis determined the molecular ion mass to be 841.34 (theoretical value: 841.03).

[0122] Synthesis Example 11: Synthesis of S141

[0123]

[0124] Synthesis of intermediate S141-1:

[0125] Carbazole and spirofluorene (14.54 g, 35.85 mmol), 2,6-dibromo-4-fluorobenzonitrile (10 g, 35.85 mmol), cesium carbonate (23.36 g, 71.71 mmol), and N,N-dimethylformamide (200 ml) were added to a 500 ml single-necked flask at room temperature. The reaction was carried out overnight at 120 °C under nitrogen protection. Heating was stopped, and after cooling to room temperature, 500 ml of water was added and stirred for 10 min. A large amount of white solid precipitated. The solid was filtered, and the filter cake was washed with ethanol for 2 h. After cooling, the solid was filtered again to obtain 15 g of white solid product, with a yield of 63%. The molecular ion mass determined by mass spectrometry was 664.36 (theoretical value: 664.40).

[0126] Synthesis of compound S141:

[0127] At room temperature, S141-1 (5 g, 7.53 mmol), carbazole (2.52 g, 12.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6 g of crude product. Recrystallization from toluene / ethanol gave 3 g of white solid, with a yield of 48%. Mass spectrometry analysis determined the molecular ion mass to be 836.85 (theoretical value: 837.00).

[0128] Synthesis Example 12: Synthesis of S142

[0129]

[0130] Synthesis of compound S142:

[0131] At room temperature, S1-1 (5 g, 7.53 mmol), 3,6-dimethylcarbazole (2.94 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 5 g of crude product. Recrystallization from toluene / ethanol gave 4.5 g of a white solid, with a yield of 67%. Mass spectrometry analysis determined the molecular ion mass to be 864.35 (theoretical value: 864.33).

[0132] Synthesis Example 13: Synthesis of S149

[0133]

[0134] Synthesis of intermediate S149-1:

[0135] Carbazole and spirofluorene (14.54 g, 35.85 mmol), 2,6-dibromo-4-fluorobenzonitrile (10 g, 35.85 mmol), cesium carbonate (23.36 g, 71.71 mmol), and N,N-dimethylformamide (200 ml) were added to a 500 ml single-necked flask at room temperature. The reaction was carried out overnight at 120 °C under nitrogen protection. Heating was stopped, and after cooling to room temperature, 500 ml of water was added and stirred for 10 min. A large amount of white solid precipitated. The solid was filtered, and the filter cake was washed with ethanol for 2 h. After cooling, the solid was filtered again to give 16 g of white solid product, with a yield of 67%. The molecular ion mass determined by mass spectrometry was 664.38 (theoretical value: 664.40).

[0136] Synthesis of compound S149:

[0137] At room temperature, S141-1 (5 g, 7.53 mmol), carbazole (2.52 g, 12.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The flask was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 6 g of crude product. Recrystallization from toluene / ethanol gave 3.5 g of white solid, with a yield of 56%. Mass spectrometry analysis determined the molecular ion mass to be 836.88 (theoretical value: 837.00).

[0138] Synthesis Example 14: Synthesis of S150

[0139]

[0140] Synthesis of compound S150:

[0141] At room temperature, S149-1 (5 g, 7.53 mmol), 3,6-dimethylcarbazole (2.94 g, 15.05 mmol), Pd2(dba)3 (0.69 g, 0.75 mmol), P(t-Bu)3 (0.30 g, 1.51 mmol), sodium tert-butoxide (2.17 g, 22.58 mmol), and xylene (50 ml) were added to a 100 ml single-necked flask. The mixture was purged with nitrogen three times and heated to 130 °C overnight. The reaction mixture was cooled to room temperature, filtered, and the filtrate was concentrated with silica gel. Column chromatography (PE:EA = 100:1) yielded 5 g of crude product. Recrystallization from toluene / ethanol gave 5 g of a white solid, with a yield of 74%. Mass spectrometry analysis determined the molecular ion mass to be 864.29 (theoretical value: 864.33).

[0142] Device Examples

[0143] Implementation

[0144] An OLED includes a first electrode and a second electrode, and an organic material layer located between the electrodes. This organic material layer can be further divided into multiple regions. For example, the organic material layer may include a hole transport region, a light-emitting layer, and an electron transport region.

[0145] In specific embodiments, a substrate can be used below the first electrode or above the second electrode. The substrate is typically made of glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency. Furthermore, thin-film transistors (TFTs) can also be incorporated into the substrate used for displays.

[0146] The first electrode can be formed by sputtering or depositing the material to be used as the first electrode on a substrate. When the first electrode is used as the anode, transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), and zinc oxide (ZnO) and any combination thereof can be used. When the first electrode is used as the cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag) and any combination thereof can be used.

[0147] Organic material layers can be formed on electrodes using methods such as vacuum thermal evaporation, spin coating, and printing. The compounds used as organic material layers can be small organic molecules, large organic molecules, polymers, and combinations thereof.

[0148] The hole transport region is located between the anode and the emissive layer. The hole transport region can be a single-layer hole transport layer (HTL), including single-layer hole transport layers containing only one compound and single-layer hole transport layers containing multiple compounds. Alternatively, the hole transport region can be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL); wherein the HIL is located between the anode and the HTL, and the EBL is located between the HTL and the emissive layer.

[0149] The material for the hole transport region may be selected from, but is not limited to, phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives as shown in HT-1 to HT-51 below; or any combination thereof.

[0150]

[0151]

[0152]

[0153] The hole injection layer is located between the anode and the hole transport layer. The hole injection layer can be a single compound material or a combination of multiple compounds. For example, the hole injection layer can be one or more compounds of HT-1 to HT-51 mentioned above, or one or more compounds of HI-1 to HI-3 mentioned below; it can also be one or more compounds of HT-1 to HT-51 doped with one or more compounds of HI-1 to HI-3 mentioned below.

[0154]

[0155] The emissive layer includes luminescent dyes (i.e., dopants) that can emit different wavelengths of light, and may also include a host material. The emissive layer can be a monochromatic emissive layer emitting a single color such as red, green, or blue. Multiple monochromatic emissive layers of different colors can be arranged in a planar pattern according to pixel design, or they can be stacked together to form a colored emissive layer. When different colored emissive layers are stacked together, they can be separated from each other or connected to each other. The emissive layer can also be a single colored emissive layer that can simultaneously emit different colors such as red, green, and blue.

[0156] Depending on the technology used, the light-emitting layer material can be various, including fluorescent electroluminescent materials, phosphorescent electroluminescent materials, and thermally activated delayed fluorescence materials. An OLED device can employ a single light-emitting technology or a combination of different technologies. These different light-emitting materials, categorized by technology, can emit light of the same color or different colors.

[0157] In one aspect of the invention, the light-emitting layer employs thermally activated delayed fluorescence emission technology. The main material of the light-emitting layer is selected from, but not limited to, one or more combinations of PH-1 to PH-85 described above.

[0158]

[0159]

[0160]

[0161]

[0162] In one aspect of the present invention, an electron blocking layer (EBL) is located between the hole transport layer and the light-emitting layer. The electron blocking layer may employ, but is not limited to, one or more compounds of HT-1 to HT-51 described above, or one or more compounds of PH-47 to PH-77 described above; or a mixture of one or more compounds of HT-1 to HT-51 and one or more compounds of PH-47 to PH-77 may be employed.

[0163] The OLED organic material layer may also include an electron transport region between the light-emitting layer and the cathode. The electron transport region can be a single-layer electron transport layer (ETL), including single-layer electron transport layers containing only one compound and single-layer electron transport layers containing multiple compounds. Alternatively, the electron transport region can be a multilayer structure including at least one of an electron injection layer (EIL), an electron transport layer (ETL), and a hole blocking layer (HBL).

[0164] In one aspect of the present invention, the electron transport layer material may be selected from, but not limited to, one or more combinations of ET-1 to ET-65 listed below.

[0165]

[0166]

[0167]

[0168]

[0169] In one aspect of the present invention, a hole blocking layer (HBL) is located between the electron transport layer and the light-emitting layer. The hole blocking layer may employ, but is not limited to, one or more compounds of ET-1 to ET-65, or one or more compounds of PH-1 to PH-46; or a mixture of one or more compounds of ET-1 to ET-65 and one or more compounds of PH-1 to PH-46 may be employed.

[0170] The device may also include an electron injection layer located between the electron transport layer and the cathode, and the electron injection layer material includes, but is not limited to, one or more combinations of the following.

[0171] LiQ, LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, Ca, Mg.

[0172] The fabrication process of the organic electroluminescent device in Device Example 1 is as follows:

[0173] The glass plate coated with the ITO transparent conductive layer was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, ultrasonically degreased in a acetone:ethanol mixed solvent, baked in a clean environment until all moisture was removed, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam.

[0174] The glass substrate with the anode was placed in a vacuum chamber and evacuated to a vacuum level of <1×10⁻⁶. -5Pa, on the aforementioned anolyte film, a 10 nm HT-4:HI-3 (97 / 3, w / w) mixture was vacuum thermally deposited as a hole injection layer, a 60 nm HT-4 compound as a hole transport layer, and a 5 nm HT-51 compound as an electron blocking layer; a 40 nm PH-54:S6 (100:40, w / w) binary mixture was deposited as a light-emitting layer, a 5 nm PH-28 compound as a hole blocking layer, a 25 nm ET-61:ET-57 (50 / 50, w / w) mixture as an electron transport layer, a 1 nm LiF compound as an electron injection layer, and a 150 nm aluminum metal as a cathode. The total deposition rate of all organic layers and LiF was controlled at 0.1 nm / s, and the deposition rate of the metal electrode was controlled at 1 nm / s.

[0175] The fabrication process of Device Examples 2-13 and Comparative Examples 1-3 is the same as that of Device Example 1, except that the compound S6 of the present invention, which is used as the luminescent dye, is replaced by the compounds S2, S4, S5, S7, S8, S9, S10, S26, S141, S142, S149, S150 of the present invention, compound R-1 of the prior art, compound R-2 of the prior art, and compound R-3 of the prior art.

[0176] The prior art compounds R-1, R-2, and R-3 used in the comparative examples are:

[0177]

[0178] The organic electroluminescent devices prepared by the above process were subjected to the following performance measurements:

[0179] At the same brightness, the driving voltage of organic electroluminescent devices prepared in the compound and comparative materials was measured using a digital source meter and a luminance meter; the external quantum efficiency of the organic electroluminescent devices was measured using an integrating sphere; and the luminance was measured at 1000 cd / m². 2 At a constant current, the brightness of the organic electroluminescent device decreased to 950 cd / m² under the specified brightness. 2 The time is in hours.

[0180] The specific performance data of the organic electroluminescent devices prepared in the above embodiments 1-13 and comparative examples 1-3 of the present invention are detailed in Table 1 below, wherein the lifetime value of comparative example 1 is the standard 1.0, and the lifetime values ​​in other embodiments are ratios thereof.

[0181] Table 1

[0182]

[0183]

[0184] The above results indicate that the compounds in the examples exhibit significant TADF properties compared to the compound in Comparative Example 1, thus resulting in a marked improvement in device efficiency and lifetime. Compared to the compound in Comparative Example 2, the cyano group with a carbazole-spirofluorene donor at the para-position possesses stronger planar rigidity, enhancing the overall charge transport properties of the material molecule and strengthening molecular stability, thereby improving device efficiency and lifetime. Compared to the compound in Comparative Example 3, the cyano group with two carbazole groups at the ortho- ortho-position has a certain twist angle between the ortho- and para-position groups while also exhibiting a degree of overlap to prevent excessive twisting. This facilitates increased molecular transition rates and maintains molecular stability, resulting in a significant improvement in device lifetime while only slightly increasing efficiency.

[0185] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0186] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A compound of the general formula shown in formula (3-1): R 1 It is selected from one or a combination of at least two of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl. D1' and D1" may be the same or different, and are independently selected from the structures represented by equation (Ⅰ-1) or equation (Ⅰ-2): In equation (Ⅰ-1), X 1 -X 10 Selected independently from CR 9 ,R 9 Independently selected from one or a combination of at least two of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxy, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl, and X 1 -X 5 Zhong, X 6 -X 10 Any two adjacent elements in a circle can be connected to form a ring; In equation (Ⅰ-2), X 11 -X 18 Selected independently from CR 12 ,R 12 Independently selected from one or a combination of at least two of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxy, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl, and X 11 -X 14 Zhong, X 15 -X 18 Any two adjacent elements in a circle can be connected to form a ring; D2 is selected from any of the following groups: R 2 R 3 R 4 R 5 Each of the following is independently selected from one of the following: substituted or unsubstituted C1-C12 chain alkyl, substituted or unsubstituted C3-C12 cycloalkyl, substituted or unsubstituted C1-C12 alkoxy, substituted or unsubstituted C1-C12 thioalkoxy, halogen, cyano, nitro, hydroxyl, substituted or unsubstituted C1-C12 silyl, amino, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C3-C30 heteroarylamino, substituted or unsubstituted C6-C30 monocyclic aryl, substituted or unsubstituted C10-C30 fused-ring aryl, substituted or unsubstituted C3-C30 monocyclic heteroaryl, and substituted or unsubstituted C6-C30 fused-ring heteroaryl; b, d, c, and e are 0; a' is selected from 0; when the above groups contain substituents, the substituents are selected from one or a combination of at least two of the following: halogen, cyano, nitro, hydroxyl, C1-C12 chain alkyl, C3-C12 cycloalkyl, C1-C12 alkoxy, C1-C12 thioalkoxy, C1-C12 silyl, amino, C6-C30 arylamino, C3-C30 heteroarylamino, C6-C30 monocyclic aryl, C10-C30 fused-ring aryl, C3-C30 monocyclic heteroaryl, and C6-C30 fused-ring heteroaryl.

2. In the compound according to claim 1, D1' and D1" are each independently selected from any one of the following groups:

3. The compound according to claim 1, wherein D2 is selected from any one of the following groups:

4. A compound selected from the following structures:

5. The application of any of the compounds described in claims 1-4 is as a luminescent material in large-area sensors, electronic paper, or organic electroluminescent devices, such as optical sensors, solar cells, lighting elements, organic thin-film transistors, organic field-effect transistors, organic thin-film solar cells, information tags, electronic artificial skin sheets, sheet-type scanners, etc.

6. The application of the compound as described in claim 5, as a light-emitting layer dye and / or sensitizer in the organic electroluminescent device.

7. An organic electroluminescent device, comprising an anode layer, a plurality of light-emitting functional layers, and a cathode layer; wherein the plurality of light-emitting functional layers include at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, and an electron transport layer formed sequentially, the hole injection layer being formed on the anode layer, and the cathode layer being formed on the electron transport layer; wherein, The light-emitting layer contains an organic compound as described in any one of claims 1-4.

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