Thermal activation delayed fluorescence material, preparation method thereof and luminescent device

Abstract

The invention discloses a thermally activated delayed fluorescent material, a preparation method thereof and a luminescent device, and relates to the technical field of organic luminescent materials. The structural formula of the thermal activation delayed fluorescence material is shown in the specification, wherein R1 is H, tert-butyl or methyl, and R1 is located at any connectable position on a benzene ring; r < 2 >, R < 3 >, R < 4 > and R < 5 > are each independently H, tert-butyl or phenyl; a is an m-cyanophenyl group, a p-cyanophenyl group, a cyano group, or; representing a connection site; r6 is H or alkyl, R6 is located at any connectable position on a benzene ring, and M is O or N. The thermally activated delayed fluorescence material provided by the invention has relatively high fluorescence quantum yield and rapid reverse intersystem crossing rate, emits dark blue light, has the emission wavelength of 444-457 nm, is matched with a dark blue light MR material with a narrow-band emission characteristic, and has a wide application prospect. Therefore, the thermal activation delayed fluorescence material provided by the invention can be used as a sensitizer to realize preparation of a deep blue light super-fluorescence device.

Description

Technical Field

[0001] This invention relates to the field of organic light-emitting materials technology, and in particular to a thermally activated delayed fluorescence material, its preparation method, and a light-emitting device. Background Technology

[0002] Organic light-emitting diode (OLED) devices have many advantages, including simple manufacturing process, low power consumption, low cost, and flexible display capabilities, making them the most promising third-generation display technology. Light-emitting materials are the core materials in organic light-emitting diodes.

[0003] High-color-purity deep blue organic light-emitting diodes that fully meet the BT.2020 standard must have a color coordinate y-value (CIEy) less than or equal to 0.046, which places extremely high demands on the maximum emission wavelength and full width at half maximum (FWHM) of the luminescent material. While thermally activated delayed fluorescence (TADF) materials based on long-range charge transfer (LR-CT) have high efficiency and low device roll-off, their broad emission peaks cannot meet the high color purity requirements. On the other hand, multi-resonance (MR) luminescent materials with narrow-band emission offer high color purity but suffer from large device roll-off.

[0004] Cyano-containing polycarbazole-substituted benzene (CzBN) is a classic class of thermally activated delayed fluorescence materials (Nature 2012, 492, 234, Sci. Adv. 2017, 3, e1603282.), which possess high fluorescence quantum yield (PLQY) and fast reverse intersystem crossing rate (…). k RISC CzBN derivatives can be used as luminescent materials in organic light-emitting diodes (OLEDs) and as sensitizers in superfluorescent devices. However, the emission spectra of CzBN derivatives are typically located in the blue to green light region, which does not match the narrow-band emission characteristics of deep blue MR materials. Therefore, they cannot be used as sensitizers to prepare deep blue superfluorescent devices.

[0005] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a thermally activated delayed fluorescence material, its preparation method and light-emitting device, aiming to provide a light-emitting material whose emission light is located in the deep blue light region and matches the deep blue light MR material, so as to further prepare deep blue light superfluorescent devices.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a thermally activated delayed fluorescence material, wherein the structural formula of the thermally activated delayed fluorescence material is: ; Wherein, R1 is H, tert-butyl, or methyl, and R1 is located at any position on the benzene ring that can be connected; R2, R3, R4, and R5 are each independently H, tert-butyl, or phenyl; A is m-benzonitrile, p-benzonitrile, cyano, or ; Indicates the connection site; R6 is H or alkyl (e.g., methyl, ethyl, tert-butyl, etc.), R6 is located at any connectable position on the benzene ring, and M is O (oxygen) or N (nitrogen).

[0008] In the following text, the specific groups A, R1, R2, R3, R4 and R5 involved in different structural formulas are the same as those here. When A, R1, R2, R3, R4 and R5 appear again in the following text, their meanings will not be repeated.

[0009] The thermally activated delayed fluorescence material provided by this invention has a high fluorescence quantum yield and a fast reverse intersystem crossing rate, with an emission wavelength of 444~457nm. It is matched with deep blue MR materials with narrow-band emission characteristics. Therefore, the thermally activated delayed fluorescence material provided by this invention can be used as a sensitizer to be combined with deep blue MR materials to realize the fabrication of high color purity and high performance deep blue superfluorescent devices.

[0010] This invention replaces the cyano group in CzBN with a boron-oxygen MR electron acceptor to construct a class of hybrid long-range-short-range charge transfer thermally activated delayed fluorescence material molecules with a polycarbazole-substituted benzene structure, to match narrow-band deep blue MR luminescent materials for use in superfluorescent devices. Furthermore, through molecular structure engineering, such as peripheral modification and the introduction of a second acceptor, the light color and radiative transition rate of the thermally activated delayed fluorescence material molecules can be controlled. k r The deep blue photothermally activated delayed fluorescence material contains a poly-tert-butylcarbazole-substituted benzene backbone. This structure ensures high fluorescence quantum yield and thermally activated delayed fluorescence characteristics. The introduction of tert-butyl groups can suppress the Dexter energy transfer process in electroluminescent devices. The introduction of boron-oxygen MR-type acceptors has the following advantages: First, the boron-oxygen acceptor building block has empty... p The boron atoms in the orbital are far from the central benzene ring, thus weakening the charge transfer from the carbazole donor to the boron-oxygen acceptor, making deep blue light emission possible. Secondly, the planar and large boron-oxygen acceptor moiety can induce a close, face-to-face donor-acceptor arrangement, thereby promoting thermally activated delayed fluorescence through space charge transfer channels and accelerating the radiative transition rate through short-range interactions. Thirdly, the MR-type boron-oxygen acceptor moiety can further enhance the radiative transition rate of the luminescent material through inherent short-range electronic interactions. In addition, this invention further modulates the photophysical properties of the material by adjusting the electron-pulling capabilities of the peripheral substituents and introducing a second acceptor.

[0011] Optionally, the thermally activated delayed fluorescence material is selected from one of the following structures:

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025] ; where ph represents phenyl.

[0026] A second aspect of the present invention provides a method for preparing the thermally activated delayed fluorescence material as described above, comprising the following steps: Will , , , and After the reaction, the thermally activated delayed fluorescence material is obtained.

[0027] In this invention, the carbazole group is attached to the precursor molecule through a nucleophilic reaction to obtain the target compound.

[0028] Optionally, The preparation method includes the following steps: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error and After the reaction, we get Wherein, -B(pin) represents pinacol boronic acid ester group ( ).

[0029] In this invention, a boron group is attached to a benzene ring via a Suzuki coupling reaction.

[0030] Optionally, The preparation method includes the following steps: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error After reacting with AB (pin), we obtain In this invention, electron-withdrawing groups are attached to the benzene ring via a Suzuki coupling reaction.

[0031] Optionally, The preparation method includes the following steps: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error A mixture of n-BuLi, BBr3, o-dichlorobenzene (o-DCB), and N,N-diisopropylethylamine (DIPEA) was reacted to yield... ;Will After reacting with B2(pin)2 (i.e., bis-pinacol diborane), the following is obtained: .

[0032] In this invention, The synthetic route is as follows: .

[0033] The specific method is as follows: Take a pressure-resistant bottle and add argon gas under argon protection. Add o-DCB and stir for 0.3 h. Slowly add a solution of n-butyllithium pentane at 0 °C, stir for 0.5 h, then react at room temperature for 1 h, followed by reaction at 60 °C for 0.3 h. After removing low-boiling molecules such as pentane under vacuum, add boron tribromide at -78 °C. Stir the reaction mixture at room temperature for 0.5 h, then react at room temperature for 1 h. Add DIPEA at 0 °C, then bring the reaction mixture to room temperature and stir overnight at 180 °C. After cooling to room temperature, filter through diatomaceous earth and extract three times with DCM (dichloromethane) and water. Dry the combined organic phases with anhydrous Na₂SO₄ and concentrate under reduced pressure. Purify the crude product by silica gel column chromatography using DCM and PE (petroleum ether) (DCM to PE volume ratio 1:10) as eluent. .

[0034] Take a two-necked flask and add [the following] under nitrogen protection. A mixture of B2(pin)2, Pd(dppf)Cl2, potassium acetate (AoCK), and 1,4-dioxane was reacted at 100 °C for 8 h. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (v / v) as eluents to obtain... .in, The synthetic route is as follows: .

[0035] The specific steps are as follows: Take two flasks, and add argon gas under argon protection. , Potassium carbonate and N,N-dimethylformamide (DMF) were reacted at 100 °C for 24 h. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (v / v) as eluents to give a white solid.

[0036] As an example, the thermally activated delayed fluorescence material can be prepared according to the following synthesis route 1, synthesis route 2 or synthesis route 3.

[0037] Synthesis Route 1:

[0038] Synthesis Route 2:

[0039] Synthesis Route 3: .

[0040] A third aspect of the present invention provides a light-emitting device, wherein the light-emitting device comprises the thermally activated delayed fluorescence material described above.

[0041] Optionally, the light-emitting device includes a light-emitting layer, which includes the thermally activated delayed fluorescence material.

[0042] Optionally, the light-emitting device includes a light-emitting layer, which comprises a host material and a guest material, wherein the guest material includes the thermally activated delayed fluorescence material.

[0043] In this embodiment, the corresponding light-emitting device is specifically an organic electroluminescent device. In some embodiments, the guest material accounts for 5% to 30% of the mass of the host material (for example, it can be 5%, 10%, 15%, 20%, 25%, or 30%, etc.).

[0044] Optionally, the light-emitting device includes a light-emitting layer, which comprises a host material, a guest material, and a sensitizer, wherein the sensitizer includes the thermally activated delayed fluorescence material. In this embodiment, the corresponding light-emitting device is specifically a deep blue superfluorescent device.

[0045] In some embodiments, the photosensitizer accounts for 5% to 30% of the mass of the host material (e.g., 5%, 10%, 15%, 20%, 25%, or 30%), and the guest material accounts for 0.1% to 3% of the mass of the host material (e.g., 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, or 3%).

[0046] Beneficial effects: The thermally activated delayed fluorescence material provided by this invention has a high fluorescence quantum yield and a fast reverse intersystem crossing rate, and emits deep blue light with an emission wavelength of 444~457 nm, which matches the deep blue light MR material with narrow band emission characteristics. Therefore, the thermally activated delayed fluorescence material provided by this invention can be used as a sensitizer to realize the fabrication of deep blue light superfluorescent devices. Attached Figure Description

[0047] Figure 1 The image shows the UV-Vis absorption and fluorescence emission spectra of compound A prepared in Example 1 in a diluted toluene solution.

[0048] Figure 2 The image shows the UV-Vis absorption and fluorescence emission spectra of compound C prepared in Example 3 in a diluted toluene solution.

[0049] Figure 3 The image shows the UV-Vis absorption and fluorescence emission spectra of compound E prepared in Example 5 in a diluted toluene solution.

[0050] Figure 4 The graph shows the lifetime test results of compound A prepared in Example 1 in toluene solution.

[0051] Figure 5 The graph shows the lifetime test results of compound C prepared in Example 3 in toluene solution.

[0052] Figure 6 The graph shows the lifetime test results of compound E prepared in Example 5 in toluene solution.

[0053] Figure 7 This is a schematic diagram of the organic electroluminescent device in Application Example 1.

[0054] Figure 8 The graph shows the maximum external quantum efficiency of the organic electroluminescent devices in Application Examples 1 to 3 as a function of brightness.

[0055] Figure 9 The emission spectra of the sensitizer and guest material in the superfluorescent device of Application Example 4 are shown in toluene solution.

[0056] Figure 10The graph shows the maximum external quantum efficiency as a function of brightness for the superfluorescent device in Application Example 4 and the light-emitting device in Comparative Example 1. Detailed Implementation

[0057] This invention provides a thermally activated delayed fluorescence material, its preparation method, and a light-emitting device. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0059] The present invention will be further described below through specific embodiments.

[0060] Unless otherwise specified, all raw materials used in the following examples are commercially available products. Among them, boron oxide acceptor compounds ( R1 (which is tert-butyl, methyl, or H) can be purchased directly or prepared by the preparation method described above in this invention.

[0061] Example 1 The preparation of thermally activated delayed fluorescence material, i.e., compound A, includes the following steps: (1) Preparation of compound 3a:

[0062] Following the synthetic route described above, a 200 mL two-necked flask was filled with compound 1 (0.65 g, 2.1 mmol), compound 2a (0.24 g, 2 mmol), Pd(PPh3)4 (0.18 g, 0.2 mmol), potassium carbonate (0.28 g, 2.5 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 h. After cooling to room temperature, the mixture was filtered through diatomaceous earth and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 3a (0.48 g, 72% yield).

[0063] The 1H NMR spectrum data of compound 3a are as follows: 1 H NMR (500 MHz, Chloroform- d) δ 7.75 – 7.69 (m, 2H), 7.50 – 7.45 (m, 2H).

[0064] (2) Preparation of compound 5a:

[0065] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 3a (0.66 g, 2 mmol), compound 4a (0.56 g, 2.2 mmol), Pd(PPh3)4 (0.30 g, 0.35 mmol), potassium carbonate (0.61 g, 4.4 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 5a (0.59 g, 78% yield).

[0066] The proton NMR spectrum data of compound 5a are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.74 – 7.69 (m, 2H), 7.52 – 7.46 (m, 2H), 1.24 (s, 12H).

[0067] (3) Preparation of compound A:

[0068] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 5a (0.86 g, 1.4 mmol), 3,6-di-tert-butylcarbazole (1.96 g, 7 mmol), potassium carbonate (1.38 g, 10 mmol), and 60 mL of DMF under argon protection. The reaction was carried out at 150 °C for 8 hours. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio 1:10) as eluents to give compound A (2.1 g, 90% yield).

[0069] The proton NMR spectrum data of compound A are as follows: 1 H NMR (500 MHz, Chloroform- d )δ 8.06 (t, J=1.3 Hz, 4H), 7.92 (d, J = 2.3 Hz, 4H), 7.84 (d, J = 7.8 Hz, 4H), 7.64 – 7.58 (m, 2H), 7.50 – 7.44 (m, 4H), 7.37 (d, J = 1.6 Hz, 8H), 7.28 (dd, J = 7.0, 2.1 Hz, 2H), 7.24 (dd, J = 7.7, 2.3Hz, 4H), 6.88 – 6.80 (m, 4H), 1.34 (s, 90H).

[0070] The carbon NMR spectrum data of compound A are as follows: 13 C NMR (126 MHz, Chloroform- d )δ 160.02, 155.90, 142.57, 142.41, 138.73, 138.25, 137.50, 136.44, 134.19, 123.81, 123.39, 122.40 , 115.58, 115.47, 115.34, 115.26, 111.00, 34.45, 34.34, 32.26, 32.12, 32.01, 31.91, 31.76, 31.52.

[0071] The high-resolution mass spectrometry data for compound A are: HRMS (ESI) m / z calcd for C 111 H 111 BN5O2[M+H] + 1556.8799, found 1556.8825 (calcd for indicates theoretical calculation result, found indicates actual analysis result; the meaning of calcd for and found in the following text is the same as here).

[0072] Example 2 The preparation of thermally activated delayed fluorescence material, namely compound B, includes the following steps: (1) Preparation of compound 3b:

[0073] Following the synthetic route described above, a 200 mL two-necked flask was filled with compound 1 (0.65 g, 2.1 mmol), compound 2b (0.24 g, 2 mmol), Pd(PPh3)4 (0.18 g, 0.2 mmol), potassium carbonate (0.28 g, 2.5 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 h. After cooling to room temperature, the mixture was filtered through diatomaceous earth and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 3b (0.48 g, 72% yield).

[0074] The 1H NMR spectrum data of compound 3b are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.75 – 7.69 (m, 2H), 7.50 – 7.45 (m, 2H).

[0075] (2) Preparation of compound 5b:

[0076] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 3a (0.66 g, 2 mmol), compound 4b (0.56 g, 2.2 mmol), Pd(PPh3)4 (0.30 g, 0.35 mmol), potassium carbonate (0.61 g, 4.4 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 5b (0.7 g, 65% yield).

[0077] The 1H NMR data of compound 5b are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.74 – 7.69 (m, 2H), 7.52 – 7.46 (m, 2H), 1.24 (s, 12H).

[0078] (3) Preparation of compound B:

[0079] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 5b (0.86 g, 1.4 mmol), 3,6-di-tert-butylcarbazole (1.96 g, 7 mmol), potassium carbonate (1.38 g, 10 mmol), and 60 mL of DMF under argon protection. The reaction was carried out at 150 °C for 8 hours. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio 1:10) as eluents to give compound B (1.2 g, 80% yield).

[0080] The proton NMR spectrum data of compound B are as follows: 1 H NMR (500 MHz, Chloroform- d )δ 8.06 (t, J =1.3 Hz, 4H), 7.92 (d, J = 2.3 Hz, 4H), 7.84 (d, J = 7.8 Hz, 4H), 7.64 – 7.58 (m, 2H), 7.50 – 7.44 (m, 4H), 7.37 (d, J = 1.6 Hz, 8H), 7.28 (dd, J = 7.0, 2.1 Hz, 2H), 7.24 (dd, J = 7.7, 2.3Hz, 4H), 6.88 – 6.80 (m, 4H), 1.34 (s, 90H).

[0081] The carbon NMR spectrum data of compound B are as follows: 13 C NMR (126 MHz, Chloroform- d )δ 158.24, 156.07, 144.55, 143.74, 142.53, 142.31, 140.05, 139.02, 138. 62, 138.20, 137.43, 136.36, 131.08, 129.92, 129.79, 129.20, 123.77, 12 3.38, 122.33, 115.54, 115.48, 115.29, 110.97, 109.60, 109.19, 108.92 , 34.44, 34.35, 32.26, 32.14, 32.02, 31.94, 31.76, 31.53, 31.29, 31.02.

[0082] The high-resolution mass spectrometry data for compound B are: HRMS (ESI) m / z calcd for C 119 H 126 BN5O2[M+H] + 1668.9756, found 1669.2468.

[0083] Example 3 The preparation of thermally activated delayed fluorescence material, namely compound C, includes the following steps: (1) Preparation of compound 3a: The preparation method is the same as that of compound 3a in Example 1.

[0084] (2) Preparation of compound 5c:

[0085] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 3a (0.66 g, 2 mmol), compound 4b (0.56 g, 2.2 mmol), Pd(PPh3)4 (0.30 g, 0.35 mmol), potassium carbonate (0.61 g, 4.4 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 5c (0.59 g, 78% yield).

[0086] The proton NMR spectrum data of compound 5c are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.74 – 7.69 (m, 2H), 7.52 – 7.46 (m, 2H), 1.24 (s, 12H).

[0087] (3) Preparation of compound C:

[0088] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 5c (0.86 g, 1.4 mmol), 3,6-di-tert-butylcarbazole (1.96 g, 7 mmol), potassium carbonate (1.38 g, 10 mmol), and 60 mL of DMF under argon protection. The reaction was carried out at 150 °C for 8 hours. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio 1:10) as eluents to give compound C (1.5 g, 70% yield).

[0089] The proton NMR spectrum data of compound C are as follows: 1 H NMR (500 MHz, Chloroform- d )δ 8.06 (t, J =1.3 Hz, 4H), 7.92 (d, J = 2.3 Hz, 4H), 7.84 (d, J = 7.8 Hz, 4H), 7.64 – 7.58 (m, 2H), 7.50 – 7.44 (m, 4H), 7.37 (d, J = 1.6 Hz, 8H), 7.28 (dd, J = 7.0, 2.1 Hz, 2H), 7.24 (dd, J = 7.7, 2.3Hz, 4H), 6.88 – 6.80 (m, 4H), 1.34 (s, 90H).

[0090] The carbon NMR spectrum data of compound C are as follows: 13 C NMR (126 MHz, Chloroform- d )δ 160.02, 155.90, 142.57, 142.41, 138.73, 138.25, 137.50, 136.44, 134.19, 123.81, 123.39, 122.40 , 115.58, 115.47, 115.34, 115.26, 111.00, 34.45, 34.34, 32.26, 32.12, 32.01, 31.91, 31.76, 31.52.

[0091] The high-resolution mass spectrometry data for compound C are: HRMS (ESI) m / z calcd for C 111 H 111 BN5O2[M+H] + 1668.3498, found 1668.8975.

[0092] Example 4 The preparation of thermally activated delayed fluorescence material, namely compound D, includes the following steps: (1) Preparation of compound 3a: The preparation method is the same as that of compound 3a in Example 1.

[0093] (2) Preparation of compound 5d:

[0094] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 3a (0.66 g, 2 mmol), compound 4c (0.56 g, 2.2 mmol), Pd(PPh3)4 (0.30 g, 0.35 mmol), potassium carbonate (0.61 g, 4.4 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 5d (0.78 g, 78% yield).

[0095] The 1H NMR spectrum data of compound 5d are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.74 – 7.69 (m, 2H), 7.52 – 7.46 (m, 2H), 1.24 (s, 12H).

[0096] (3) Preparation of compound D:

[0097] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 5d (0.86 g, 1.4 mmol), 3,6-diphenylcarbazole (1.96 g, 7 mmol), potassium carbonate (1.38 g, 10 mmol), and 60 mL of DMF under argon protection. The mixture was reacted at 150 °C for 8 hours, cooled to room temperature, and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio 1:10) as eluents to give compound D (0.40 g, 30% yield).

[0098] The proton NMR spectrum data of compound D are as follows:1 H NMR (500 MHz, Chloroform- d )δ 8.06 (t, J =1.3 Hz, 4H), 7.92 (d, J = 2.3 Hz, 4H), 7.84 (d, J = 7.8 Hz, 4H), 7.64 – 7.58 (m, 2H), 7.50 – 7.44 (m, 4H), 7.37 (d, J = 1.6 Hz, 8H), 7.28 (dd, J = 7.0, 2.1 Hz, 2H), 7.24 (dd, J = 7.7, 2.3Hz, 4H), 6.88 – 6.80 (m, 4H), 1.34 (s, 90H).

[0099] The carbon NMR spectrum data of compound D are as follows: 13 C NMR (126 MHz, Chloroform- d )δ 158.24, 156.07, 144.55, 143.74, 142.53, 142.31, 140.05, 139.02, 138. 62, 138.20, 137.43, 136.36, 131.08, 129.92, 129.79, 129.20, 123.77, 12 3.38, 122.33, 115.54, 115.48, 115.29, 110.97, 109.60, 109.19, 108.92 , 34.44, 34.35, 32.26, 32.14, 32.02, 31.94, 31.76, 31.53, 31.29, 31.02.

[0100] The high-resolution mass spectrometry data for compound D are: HRMS (ESI) m / z calcd for C 129 H 82 BN5O2[M+H] + 1744.2647, found 1744.6498.

[0101] Example 5 The preparation of thermally activated delayed fluorescence material, namely compound E, includes the following steps: (1) Preparation of compound 5e:

[0102] Following the synthetic route described above, a 200 mL two-necked flask was filled with compound 1 (0.65 g, 2.1 mmol), compound 4a (0.24 g, 2 mmol), Pd(PPh3)4 (0.18 g, 0.2 mmol), potassium carbonate (0.28 g, 2.5 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 h. After cooling to room temperature, the mixture was filtered through diatomaceous earth and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 5e (0.70 g, yield 52%).

[0103] The proton NMR spectrum data of compound 5e are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.75 – 7.69 (m, 2H), 7.50 – 7.45 (m, 2H).

[0104] (2) Preparation of compound E:

[0105] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 5e (0.86 g, 1.4 mmol), 3,6-di-tert-butylcarbazole (1.96 g, 7 mmol), Cs₂CO₃ (1.38 g, 10 mmol), and 60 mL of DMF under argon protection. The reaction was carried out at 150 °C for 12 hours. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio 1:10) as eluents to give compound E (0.66 g, yield 45%).

[0106] The proton NMR spectrum data of compound E are as follows: 1 H NMR (500 MHz, Chloroform- d )δ 8.06 (t, J =1.3 Hz, 4H), 7.92 (d, J = 2.3 Hz, 4H), 7.84 (d, J = 7.8 Hz, 4H), 7.64 – 7.58 (m, 2H), 7.50 – 7.44 (m, 4H), 7.37 (d, J= 1.6 Hz, 8H), 7.28 (dd, J = 7.0, 2.1 Hz, 2H), 7.24 (dd, J = 7.7, 2.3 Hz, 4H), 6.88 – 6.80 (m, 4H), 1.34 (s, 90H).

[0107] The carbon NMR spectrum data of compound E are as follows: 13 C NMR (126 MHz, Chloroform- d )δ 160.02, 155.90, 142.57, 142.41, 138.73, 138.25, 137.50, 136.44, 134.19, 123.81, 123.39, 122.40 , 115.58, 115.47, 115.34, 115.26, 111.00, 34.45, 34.34, 32.26, 32.12, 32.01, 31.91, 31.76, 31.52.

[0108] The high-resolution mass spectrometry data for compound E are: HRMS (ESI) m / z calcd for C 122 H 116 B2N4O4[M+H] + 1723.9758, found 1723.9775.

[0109] Example 6 The preparation of thermally activated delayed fluorescence material, namely compound F, includes the following steps: (1) Preparation of compound 3c:

[0110] Following the synthetic route described above, a 200 mL two-necked flask was filled with compound 1 (0.65 g, 2.1 mmol), compound 2c (0.24 g, 2 mmol), Pd(PPh3)4 (0.18 g, 0.2 mmol), potassium carbonate (0.28 g, 2.5 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 h. After cooling to room temperature, the mixture was filtered through diatomaceous earth and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 3c (0.439 g, yield 49%).

[0111] The proton NMR spectrum data of compound 3c are as follows:1 H NMR (500 MHz, Chloroform- d ) δ 7.75 – 7.69 (m, 2H), 7.50 – 7.45 (m, 2H).

[0112] (2) Preparation of compound 5f:

[0113] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 3c (0.66 g, 2 mmol), compound 4a (0.56 g, 2.2 mmol), Pd(PPh3)4 (0.30 g, 0.35 mmol), potassium carbonate (0.61 g, 4.4 mmol), and 60 mL of a toluene / ethanol / water mixture (in a volume ratio of 3:1:1) under argon protection. The mixture was reacted at 85 °C for 48 hours. After the reaction was complete, the mixture was cooled to room temperature, filtered through diatomaceous earth, and extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio of 1:10) as eluents to give compound 5f (0.76 g, 53% yield).

[0114] The proton NMR spectrum data of compound 5f are as follows: 1 H NMR (500 MHz, Chloroform- d ) δ 7.74 – 7.69 (m, 2H), 7.52 – 7.46 (m, 2H), 1.24 (s, 12H).

[0115] (3) Preparation of compound F:

[0116] Following the synthetic route described above, a 250 mL two-necked flask was filled with compound 5f (0.86 g, 1.4 mmol), 3,6-di-tert-butylcarbazole (1.96 g, 7 mmol), Cs₂CO₃ (1.38 g, 10 mmol), and 60 mL of DMF under argon protection. The reaction was carried out at 150 °C for 12 hours. After cooling to room temperature, the mixture was extracted three times with DCM and water. The combined organic phases were dried over anhydrous Na₂SO₄ and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography using DCM and PE (DCM to PE volume ratio 1:10) as eluents to give compound F (1.03 g, yield 63%).

[0117] The proton NMR spectrum data of compound F are as follows: 1H NMR (500 MHz, Chloroform- d )δ 8.06 (t, J =1.3 Hz, 4H), 7.92 (d, J = 2.3 Hz, 4H), 7.84 (d, J = 7.8 Hz, 4H), 7.64 – 7.58 (m, 2H), 7.50 – 7.44 (m, 4H), 7.37 (d, J = 1.6 Hz, 8H), 7.28 (dd, J = 7.0, 2.1 Hz, 2H), 7.24 (dd, J = 7.7, 2.3Hz, 4H), 6.88 – 6.80 (m, 4H), 1.34 (s, 90H).

[0118] The carbon NMR spectrum data of compound F are as follows: 13 C NMR (126 MHz, Chloroform- d )δ 159.94, 156.01, 143.47, 142.84, 141.21, 138.04, 137.98, 136.72, 124.33, 123.93, 122.87, 122 .47, 118.14, 115.88, 115.62, 115.37, 109.50, 34.55, 34.37, 32.06, 31.91, 31.78, 31.70, 31.51.

[0119] The high-resolution mass spectrometry data for compound F are: HRMS (ESI) m / z calcd for C 125 H 120 BN7O2[M+H] + 1761.297, found 1762.7898.

[0120] test: Compounds A, C, and E, prepared in Examples 1, 3, and 5, were dissolved in toluene solution (each compound having a concentration of 10). -5 The UV-Vis absorption and fluorescence emission spectra of the sample (mol / L) are shown below. Figure 1 , Figure 2 and Figure 3As shown in the figure (where Wavelength represents wavelength, Normalized Abs. Intensity represents normalized absorbance intensity, Normalized PL Intensity represents normalized fluorescence intensity, and FWHM represents full width at half maximum), the UV-Vis absorption spectra show that compounds A, C, and E all have a characteristic absorption band of the boron-oxygen fragment at 340 nm. The absorption wavelength of compound A is 360 nm, the absorption wavelength of compound C is 360 nm, and the absorption wavelength of compound E is 380 nm. The fluorescence emission spectra show that the maximum emission wavelengths of the three compounds are 457 nm, 444 nm, and 455 nm, respectively.

[0121] Compounds A, C, and E, prepared in Examples 1, 3, and 5, were dissolved in toluene solution (each compound having a concentration of 10). -5 The lifetime test results in mol / L are as follows: Figure 4 , Figure 5 and Figure 6 As shown in the figure (where Time represents time and Normalized Counts represents normalized counts), it can be seen that all compounds exhibit significant delayed luminescence under deoxygenation conditions. Under oxygen-enriched conditions, triplet excitons are quenched, and the delayed component decreases, proving that these compounds possess thermally activated delayed fluorescence (TADF) properties.

[0122] In the following application examples, Liq is 8-hydroxyquinoline-lithium; the specific structural formulas of HAT-CN, TAPC, TCTA, mCBP, SiTrzCz2, and ANT-BIZ involved are as follows:

[0123] .

[0124] Application Example 1 like Figure 7 As shown, this application example provides an organic electroluminescent device, which includes an ITO electrode layer, a HAT-CN layer (thickness of 5 nm), a TAPC layer (thickness of 30 nm), a TCTA layer (thickness of 15 nm), an mCBP layer (thickness of 10 nm), a light-emitting layer (thickness of 40 nm), an ANT-BIZ layer (thickness of 30 nm), a Liq layer (thickness of 2 nm), and an Al electrode layer (thickness of 100 nm) stacked sequentially; each layer is prepared by vacuum evaporation.

[0125] The light-emitting layer is composed of SiTrzCz2 and compound A prepared in Example 1, and compound A accounts for 15% of the mass of SiTrzCz2.

[0126] The specific structure is denoted as ITO / HAT-CN / TAPC / TCTA / mCBP / SiTrzCz2: compound A / ANT-BIZ / Liq / Al.

[0127] Application Example 2 This application example provides an organic electroluminescent device, which differs from Application Example 1 only in that compound A is replaced with compound C prepared in Example 3.

[0128] Application Example 3 This application example provides an organic electroluminescent device, which differs from Application Example 1 only in that compound A is replaced with compound E prepared in Example 5.

[0129] The maximum external quantum efficiency of the organic electroluminescent devices in Application Examples 1 to 3 varies with brightness as shown in the graphs below. Figure 8 As shown in the figure (where Luminance represents brightness), the maximum external quantum efficiencies of the organic electroluminescent devices in Application Examples 1, 2, and 3 are 21.9%, 20.7%, and 25.6%, respectively, at a brightness of 1000 cd / m². 2 At these times, the maximum external quantum efficiencies were 19.9%, 20.1%, and 21.0%, respectively, at a brightness of 10000 cd / m². 2 The maximum external quantum efficiencies were 16.6%, 17.8%, and 14.6%, respectively. The specific device efficiencies are shown in Table 1.

[0130] Table 1. Device Efficiency

[0131] in, λ EL The emission wavelength is FWHM, and the peak width at half maximum (FWHM) is the full width at half maximum (FWHM).

[0132] Application Example 4 This embodiment provides a superfluorescent device, wherein the superfluorescent device comprises an ITO electrode layer, a HAT-CN layer (thickness of 5 nm), a TAPC layer (thickness of 30 nm), a TCTA layer (thickness of 15 nm), an mCBP layer (thickness of 10 nm), a light-emitting layer (thickness of 40 nm), an ANT-BIZ layer (thickness of 30 nm), a Liq layer (thickness of 2 nm), and an Al electrode layer (thickness of 100 nm) stacked sequentially; each layer is prepared by vacuum evaporation.

[0133] The light-emitting layer is composed of SiTrzCz2 (host material), compound A (photosensitizer) prepared in Example 1, and BOBOZ (guest material); compound A accounts for 10% of the mass of SiTrzCz2, and BOBOZ accounts for 1% of the mass of SiTrzCz2.

[0134] The specific structure is denoted as: ITO / HAT-CN / TAPC / TCTA / mCBP / SiTrzCz2: compound A, BOBOZ / ANT-BIZ / Liq / Al.

[0135] Comparative Example 1 This embodiment provides a light-emitting device, which differs from Application Example 4 only in that compound A is not added.

[0136] The emission spectra of the sensitizer (compound A) and guest material (BOBOZ) in toluene solution in the superfluorescent device in Application Example 4 are shown below. Figure 9 As shown in the figure, the maximum emission wavelength of the sensitizer is 456 nm, and the maximum emission wavelength of the guest luminescent molecule is 455 nm. This demonstrates the efficient energy transfer between the sensitizer and the luminescent guest material BOBOZ in the superfluorescent device.

[0137] The maximum external quantum efficiency of the superfluorescent device in Application Example 4 and the light-emitting device (unsensitized, referred to as the control device) in Comparative Example 1 as a function of brightness is shown in the figure below. Figure 10 As shown in the figure, the maximum external quantum efficiencies of the superfluorescent device and the comparative device are 39.9% and 37.5%, respectively, at a brightness of 10000 cd / m². 2 The maximum external quantum efficiencies are 17.0% and 7.6%, respectively.

[0138] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A thermally activated delayed fluorescence material, characterized by, The structural formula of the thermally activated delayed fluorescence material is: ； wherein R1is H, t-butyl or methyl, R1is located at any available position on the phenyl ring; R2, R3, R4and R5are each independently H, t-butyl or phenyl; A is m-phenylene, p-phenylene, cyano, or ; represents the point of attachment; R6is H or alkyl, R6is located at any available position on the phenyl ring, and M is O or N.

2. The thermally activated delayed fluorescence material according to claim 1, characterized by, The thermally activated delayed fluorescence material is selected from one of the following structures: ； wherein ph is a phenyl group.

3. A method for producing the thermally activated delayed fluorescent material according to claim 1, characterized by, The method comprises the following steps: After reacting , , , and , the thermally activated delayed fluorescence material is obtained.

4. The production method according to claim 3, characterized by, The method of preparing the compound of Formula (I) comprises the steps of: After reacting with and , the following compounds are obtained ; wherein -B(pin) represents a pinacol boronate group.

5. The preparation method according to claim 4, characterized in that, The preparation method includes the following steps: The mixture of , n-BuLi, BBr3, o-dichlorobenzene and N,N-diisopropylethylamine was reacted to give ; After reaction with B2(pin)2, the following compounds were obtained After reaction with B2(pin)2, the following compounds were obtained .

6. The production method according to claim 5, characterized by, The preparation method includes the following steps: After reaction with A-B (pin), the following compounds are obtained After reaction with A-B (pin), the following compounds are obtained .

7. A light-emitting device, characterized in that, The light-emitting device comprises the thermally activated delayed fluorescence material according to any one of claims 1-2.

8. The light emitting device of claim 7, wherein, The light-emitting device comprises a light-emitting layer, and the light-emitting layer comprises the thermally activated delayed fluorescence material.

9. The light emitting device of claim 7, wherein, The light-emitting device comprises a light-emitting layer, and the light-emitting layer comprises a host material and a guest material, and the guest material comprises the thermally activated delayed fluorescence material.

10. The light emitting device of claim 7, wherein, The light-emitting device comprises a light-emitting layer, and the light-emitting layer comprises a host material, a guest material and a sensitizer, and the sensitizer comprises the thermally activated delayed fluorescence material.

Images