A near-infrared material suitable for solution processing, its preparation method and application

Abstract

This patent application discloses a near-infrared material suitable for solution processing, its preparation method, and its applications, relating to the field of organic light-emitting materials. The solution-processable near-infrared material of this patent application consists of a rigid electron acceptor fragment and a bulky electron donor fragment (N-(9,9-bis(4-(tert-butylphenyl)-9H-fluorene-2-yl)amino)-9,9-bis(4-(tert-butylphenyl))-N-phenyl-9H-fluorene-2-amine), wherein the electron acceptor fragment is diphenyl[a,c]phenazine-11,12-dinitrile. This material is a near-infrared material with thermally activated delayed fluorescence properties, and the fabricated device has a maximum external quantum efficiency of 8.33%.

Description

Technical Field

[0001] This patent application relates to the field of organic electroluminescent materials technology, and more specifically, to a near-infrared material suitable for solution processing, its preparation method, and its application. Background Technology

[0002] To date, vacuum evaporation remains the primary fabrication process for the vast majority of OLEDs, giving them advantages such as low power consumption, wide color gamut, and flexible display capabilities. The efficiency of OLED devices manufactured using this process is rapidly improving. However, the complex fabrication process and high manufacturing costs limit its industrial application. In contrast, OLED devices fabricated using solution processing have significant advantages, such as lower manufacturing costs and simpler device structures. However, the development of solution-based OLED device fabrication has been relatively slow compared to traditional evaporation methods, which is partly due to the film-forming techniques and storage environment involved in the fabrication process.

[0003] While some promising solutions for solution-processed devices have been reported in recent years, they have primarily focused on blue and green materials. In contrast, devices made from red light-emitting materials exhibit poorer performance because the non-radiative transition rate of luminescent materials increases exponentially with increasing emission wavelength. This effect is particularly pronounced in near-infrared materials, where the non-radiative transition rate has a greater influence, resulting in very few examples of high-performance solutions. Therefore, the development of solution-processable near-infrared materials is urgently needed.

[0004] Patent application content

[0005] To overcome one of the problems existing in the prior art, the primary objective of this patent application is to provide a near-infrared material suitable for solution processing. This solution-processable near-infrared material is a near-infrared material with thermally activated delayed fluorescence properties, and the fabricated device has a maximum external quantum efficiency of 8.33%.

[0006] Another objective of this patent application is to provide a method for preparing the aforementioned near-infrared material suitable for solution processing.

[0007] Another objective of this patent application is to provide the application of the aforementioned near-infrared materials suitable for solution processing in organic light-emitting devices.

[0008] The above-mentioned objective of this patent application is achieved through the following technical solution:

[0009] A near-infrared material suitable for solution processing, wherein the near-infrared material suitable for solution processing has the following molecular structure:

[0010]

[0011] This patent application also provides a method for preparing the above-mentioned near-infrared material suitable for solution processing, comprising the following steps:

[0012] S1. Preparation of intermediate D-0

[0013] Methyl o-bromobenzoate, p-chloroboronic acid, tetrakis(triphenylphosphine)palladium, and potassium carbonate were added to a two-necked flask. 1,4-dioxane and deionized water were injected under nitrogen atmosphere, and the reaction was carried out under inert gas conditions. The reaction was refluxed, and the mixture was subsequently extracted with saturated brine and ethyl acetate, respectively, to obtain the upper organic phase. The phase was then rotary evaporated and purified by column chromatography to yield intermediate D-0, the structure of which is shown below:

[0014]

[0015] S2. Preparation of intermediate D-1

[0016] 4-tert-butylphenyl magnesium bromide and D-0 were sequentially injected into a two-necked flask filled with an inert gas atmosphere. The resulting mixture was refluxed and stirred at 50°C. After the reaction was completed, the mixture was cooled and quenched with a saturated ammonium chloride solution. It was then extracted sequentially with saturated brine and dichloromethane to obtain the lower organic phase. The lower organic phase was obtained by rotary evaporation, and after the solvent was evaporated to dryness, acetic acid and hydrochloric acid were added. The mixture was then refluxed for a specified time. After the reaction was completed, the mixture was cooled and quenched with water. The precipitate was filtered, washed with methanol, and dried to finally obtain 9,9-bis(4-(tert-butyl)phenyl)-2-chloro-9H-fluorene D-1, the structure of which is shown below:

[0017]

[0018] S3. Preparation of intermediate D-2

[0019] D-1, p-chloroaniline, palladium acetate, tri-tert-butylphosphine, and potassium tert-butoxide were sequentially added to a 50 ml two-necked flask. Toluene was injected under nitrogen atmosphere, and the reaction was carried out under inert gas atmosphere and at 110 °C for 24 h under reflux. After the reaction, the mixture was extracted sequentially with saturated brine and dichloromethane to obtain the lower organic phase. The lower organic phase was then rotary evaporated and purified by column chromatography to obtain D-2, the structure of which is shown below:

[0020]

[0021] S4. Preparation of intermediate D-3

[0022] D-2, pinacol diboronate, dibenzylacetone dipalladium, potassium acetate, and 2-bicyclohexylphosphine-2',4',6'-triisopropylbiphenyl were added to a 50 ml two-necked flask. 10 ml of 1,4-dioxane was injected under nitrogen atmosphere, and the reaction was allowed to proceed under nitrogen. The mixture was then extracted with saturated brine and ethyl acetate to obtain the upper organic phase. The phase was rotary evaporated and finally purified by column chromatography to yield intermediate D-3, the structure of which is shown below:

[0023]

[0024] S5. Preparation of intermediate DCN-Br

[0025] 3-Bromo-9,10-phenanthrenequinone and 4,5-diaminophthalonitrile were placed in a single-necked flask, and 20 ml of acetic acid was added. The mixture was heated at 120 °C, cooled to room temperature, and then poured into water. The mixture was filtered, and the solid was washed with water and methanol to obtain a yellow solid intermediate, DCN-Br, whose structural formula is shown below:

[0026]

[0027] S6. Preparation of the target product DCN-SPBu

[0028] D-3, DCN-Br, tetraphenylphosphine palladium, and potassium carbonate were added to a 50 ml two-necked flask. 10 ml of 1,4-dioxane and 2 ml of deionized water were injected under nitrogen atmosphere, and the reaction was carried out at 95 °C under nitrogen atmosphere for 12 h under reflux. After the reaction, the mixture was extracted successively with saturated brine and ethyl acetate to obtain the upper organic phase. The phase was then rotary evaporated and purified by column chromatography to obtain the target product DCN-SPBu, whose structural formula is shown below:

[0029]

[0030] Preferably, the molar ratio of methyl o-bromobenzoate and p-chloroboronic acid in step S1 is 1:1.2.

[0031] Preferably, the molar ratio of 4-tert-butylphenyl magnesium bromide and D-O in step S2 is 4:1.

[0032] Preferably, in step S3, the intermediate D-1 has a molar ratio of p-chloroaniline, tri-tert-butylphosphine, and potassium tert-butoxide of 1:0.45:0.09:4.5.

[0033] Preferably, in step S1, the temperature is heated to 100°C for reaction, and the reaction time is 12 hours.

[0034] Preferably, in step S2, 15 ml of acetic acid and 2 ml of hydrochloric acid are added, and the reaction is carried out at 125°C for 4 hours under reflux.

[0035] Preferably, the method for achieving the inert gas environment in steps S1, S2 and S3 is to first evacuate the reaction device and then fill it with high-purity nitrogen or argon.

[0036] Preferably, step S4 is carried out under nitrogen atmosphere and at a temperature of 100°C, with a reflux time of 12 hours.

[0037] This patent application also provides the application of the above-mentioned near-infrared materials suitable for solution processing in organic light-emitting devices.

[0038] Compared with the prior art, the beneficial effects of this patent application are:

[0039] The near-infrared material suitable for solution processing disclosed in this patent application consists of a rigid electron acceptor fragment and a bulky electron donor fragment (N-(9,9-bis(4-(tert-butylphenyl)-9H-fluoren-2-yl)amino)-9,9-bis(4-(tert-butylphenyl))-N-phenyl-9H-fluoren-2-amine), wherein the electron acceptor fragment is diphenyl[a,c]phenazine-11,12-dinitrile. This material is a near-infrared material with thermally activated delayed fluorescence properties, and the fabricated device has a maximum external quantum efficiency of 8.33%. Attached Figure Description

[0040] Figure 1 The near-infrared material DCN-SPBu prepared for this patent application 1 HMNR diagram.

[0041] Figure 2 HRMS image of the near-infrared material DCN-SPBu prepared for this patent application.

[0042] Figure 3 Normalized absorption spectrum and fluorescence emission spectrum of the near-infrared material DCN-SPBu prepared for this patent application in toluene solution.

[0043] Figure 4 Temperature-dependent transient fluorescence spectra of the near-infrared material DCN-SPBu prepared for this patent application from 100K to 300K under nitrogen conditions.

[0044] Figure 5 Fluorescence emission spectra of the near-infrared material DCN-SPBu prepared for this patent application in hexane, toluene, and dioxane solutions.

[0045] Figure 6The near-infrared material DCN-SPBu prepared for this patent application was subjected to a nitrogen atmosphere at 10 °C / min. -1 The TGA curve was obtained by measuring the heating rate.

[0046] Figure 7 Brightness-voltage-current density diagram of the near-infrared material DCN-SPBu doped with 15wt% in a CBP thin film prepared for this patent application.

[0047] Figure 8 EQE-brightness diagram of the near-infrared material DCN-SPBu doped with 15wt% in a CBP thin film prepared for this patent application.

[0048] Figure 9 EL spectrum of the near-infrared material DCN-SPBu prepared for this patent application. Detailed Implementation

[0049] The embodiments of this patent application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of this patent application. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0050] It should be noted that:

[0051] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0052] In this patent application, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0053] Unless otherwise specified, the components or preferred components involved in this patent application may be combined with each other to form new technical solutions.

[0054] In this patent application, unless otherwise stated, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "1~5" means that all real numbers between "1~5" have been listed herein, and "1~5" is simply an abbreviation of these numerical combinations.

[0055] The “scope” disclosed in this patent application may be in the form of a lower limit and an upper limit, and may be one or more lower limits and one or more upper limits, respectively.

[0056] In this patent application, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0057] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to a person skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this patent application.

[0058] This patent application provides a near-infrared material suitable for solution processing, the near-infrared material having the molecular structure shown below:

[0059]

[0060] This patent application provides a near-infrared material suitable for solution processing, composed of a rigid electron acceptor fragment and a bulky electron donor fragment (N-(9,9-bis(4-(tert-butylphenyl)-9H-fluoren-2-yl)amino)-9,9-bis(4-(tert-butylphenyl))-N-phenyl-9H-fluoren-2-amine), wherein the electron acceptor fragment is diphenyl[a,c]phenazine-11,12-dinitrile. This material is a near-infrared material with thermally activated delayed fluorescence properties, and the fabricated device has a maximum external quantum efficiency of 8.33%.

[0061] This patent application also provides a method for preparing the aforementioned near-infrared material suitable for solution processing. The method includes the following steps:

[0062] S1. Preparation of intermediate D-0

[0063] Methyl o-bromobenzoate, p-chloroboronic acid, tetrakis(triphenylphosphine)palladium, and potassium carbonate were added to a two-necked flask. 1,4-dioxane and deionized water were injected under nitrogen atmosphere, and the reaction was carried out under inert gas conditions. The reaction was refluxed, and the mixture was subsequently extracted with saturated brine and ethyl acetate, respectively, to obtain the upper organic phase. The phase was then rotary evaporated and purified by column chromatography to yield intermediate D-0, the structure of which is shown below:

[0064]

[0065] S2. Preparation of intermediate D-1

[0066] 4-tert-butylphenyl magnesium bromide and D-0 were sequentially injected into a two-necked flask filled with an inert gas atmosphere. The resulting mixture was refluxed and stirred at 50°C. After the reaction was completed, the mixture was cooled and quenched with a saturated ammonium chloride solution. It was then extracted sequentially with saturated brine and dichloromethane to obtain the lower organic phase. The lower organic phase was obtained by rotary evaporation, and after the solvent was evaporated to dryness, acetic acid and hydrochloric acid were added. The mixture was then refluxed for a specified time. After the reaction was completed, the mixture was cooled and quenched with water. The precipitate was filtered, washed with methanol, and dried to finally obtain 9,9-bis(4-(tert-butyl)phenyl)-2-chloro-9H-fluorene D-1, the structure of which is shown below:

[0067]

[0068] S3. Preparation of intermediate D-2

[0069] D-1, p-chloroaniline, palladium acetate, tri-tert-butylphosphine, and potassium tert-butoxide were sequentially added to a 50 ml two-necked flask. Toluene was injected under nitrogen atmosphere, and the reaction was carried out under inert gas atmosphere and at 110 °C for 24 h under reflux. After the reaction, the mixture was extracted sequentially with saturated brine and dichloromethane to obtain the lower organic phase. The lower organic phase was then rotary evaporated and purified by column chromatography to obtain D-2, the structure of which is shown below:

[0070]

[0071] S4. Preparation of intermediate D-3

[0072] D-2, pinacol diboronate, dibenzylacetone dipalladium, potassium acetate, and 2-bicyclohexylphosphine-2',4',6'-triisopropylbiphenyl were added to a 50 ml two-necked flask. 10 ml of 1,4-dioxane was injected under nitrogen atmosphere, and the reaction was allowed to proceed under nitrogen. The mixture was then extracted with saturated brine and ethyl acetate to obtain the upper organic phase. The phase was rotary evaporated and finally purified by column chromatography to yield intermediate D-3, the structure of which is shown below:

[0073]

[0074] S5. Preparation of intermediate DCN-Br

[0075] 3-Bromo-9,10-phenanthrenequinone and 4,5-diaminophthalonitrile were placed in a single-necked flask, and 20 ml of acetic acid was added. The mixture was heated at 120 °C, cooled to room temperature, and then poured into water. The mixture was filtered, and the solid was washed with water and methanol to obtain a yellow solid intermediate, DCN-Br, whose structural formula is shown below:

[0076]

[0077] S6. Preparation of the target product DCN-SPBu

[0078] D-3, DCN-Br, tetraphenylphosphine palladium, and potassium carbonate were added to a 50 ml two-necked flask. 10 ml of 1,4-dioxane and 2 ml of deionized water were injected under nitrogen atmosphere, and the reaction was carried out at 95 °C under nitrogen atmosphere for 12 h under reflux. After the reaction, the mixture was extracted successively with saturated brine and ethyl acetate to obtain the upper organic phase. The phase was then rotary evaporated and purified by column chromatography to obtain the target product DCN-SPBu, whose structural formula is shown below:

[0079]

[0080] In the preparation method described in this patent application, the molar ratio of methyl o-bromobenzoate and p-chloroboronic acid in step S1 is 1:1.2.

[0081] In the preparation method described in this patent application, the molar ratio of 4-tert-butylphenyl magnesium bromide and D-O in step S2 is 4:1.

[0082] In the preparation method described in this patent application, the intermediate D-1 in step S3 has a molar ratio of p-chloroaniline, tri-tert-butylphosphine, and potassium tert-butoxide of 1:0.45:0.09:4.5.

[0083] In the preparation method described in this patent application, in step S1, the temperature is heated to 100°C for reaction, and the reaction time is 12 hours.

[0084] In the preparation method described in this patent application, in step S2, 15 ml of acetic acid and 2 ml of hydrochloric acid are added, and the reaction is carried out at 125°C for 4 hours under reflux.

[0085] In the preparation method described in this patent application, the inert gas environment in steps S1, S2, and S3 is achieved by first evacuating the reaction apparatus to a vacuum, and then filling it with high-purity nitrogen or argon.

[0086] In the preparation method described in this application, step S4 is carried out under nitrogen atmosphere and at a temperature of 100°C, with a reaction reflux time of 12 hours.

[0087] This patent application also provides the application of the above-mentioned near-infrared materials suitable for solution processing in organic light-emitting devices.

[0088] The preparation method of DCN-SPBu, a near-infrared material suitable for solution processing, will be described in detail below.

[0089] Example 1

[0090] S1. Preparation of intermediate D-0

[0091] Methyl o-bromobenzoate (1065 mg, 5 mmol), p-chloroboronic acid (936 mg, 6 mmol), tetrakis(triphenylphosphine)palladium (289 mg, 0.25 mmol), and potassium carbonate (2070 mg, 15 mmol) were added to a 100 mL two-necked flask. 25 mL of 1,4-dioxane and 5 mL of deionized water were injected under nitrogen atmosphere, and the reaction was carried out at 100 °C under nitrogen atmosphere for 12 h under reflux. After the reaction, the mixture was extracted successively with saturated brine and ethyl acetate to obtain the upper organic phase, which was then rotary evaporated. The mixture was purified by column chromatography using dichloromethane:petroleum ether in a 1:5 ratio as the developing solvent, finally yielding 1058 mg of D-0 (colorless liquid) (yield: 86%). The structure of D-0 is shown below:

[0092]

[0093] The chemical reaction equations in this preparation method are as follows:

[0094]

[0095] Example 2

[0096] S2. Preparation of intermediate D-1

[0097] 4-tert-butylphenyl magnesium bromide (34 ml, 17 mmol) and D-0 (1032 mg, 4.2 mmol) were injected sequentially into a 100 ml two-necked flask filled with nitrogen. The resulting mixture was refluxed at 50 °C and stirred for 5 h. After the reaction was complete, the mixture was cooled and quenched with a saturated ammonium chloride solution. It was then extracted sequentially with saturated brine and dichloromethane to obtain the lower organic phase. The lower organic phase was obtained by rotary evaporation, and after the solvent was evaporated to dryness, 15 ml of acetic acid and 2 ml of hydrochloric acid were added. The reaction was carried out at 125 °C and refluxed for 4 h. After the reaction was complete, the mixture was cooled and quenched with water. The precipitate was filtered, washed with methanol, and dried to give 1152 mg of D-1 (white solid) (yield: 59%). The structure of intermediate D-1 is shown below:

[0098]

[0099] The chemical reaction equations in this preparation method are as follows:

[0100]

[0101] Example 3

[0102] S3. Preparation of intermediate D-2

[0103] D-1 (464 mg, 1 mmol), p-chloroaniline (57 mg, 0.45 mmol), palladium acetate (810 mg, 0.045 mmol), tri-tert-butylphosphine (266 mg, 0.09 mmol), and potassium tert-butoxide (504 mg, 4.5 mmol) were added to a 50 mL two-necked flask. 15 mL of toluene was injected under nitrogen atmosphere, and the reaction was carried out at 110 °C under nitrogen atmosphere for 24 h under reflux. After the reaction, the mixture was extracted sequentially with saturated brine and dichloromethane to obtain the lower organic phase, which was then rotary evaporated. The mixture was purified by column chromatography using dichloromethane:petroleum ether in a 1:11 ratio as the developing solvent, finally yielding 150 mg of D-2 (white solid) (yield: 34.5%). The structural formula of D-2 is as follows:

[0104]

[0105] The chemical reaction equations in this preparation method are as follows:

[0106]

[0107] Example 4

[0108] S4. Preparation of intermediate D-3

[0109] D-2 (150 mg, 0.153 mmol), pinacol diborate (79 mg, 0.31 mmol), dibenzylacetone dipalladium (7 mg, 0.00765 mmol), potassium acetate (45 mg, 0.46 mmol), and 2-bicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (7 mg, 0.0153 mmol) were added to a 50 mL two-necked flask. 10 mL of 1,4-dioxane was injected under nitrogen atmosphere, and the reaction was carried out at 100 °C under nitrogen atmosphere for 12 h under reflux. After the reaction, the mixture was extracted with saturated brine and ethyl acetate to obtain the upper organic phase. The phase was rotary evaporated and column-sected using a dichloromethane:petroleum ether ratio of 1:9 (v / v) as the eluent. The final product was 99 mg of D-3 (white solid) (yield: 60%). The structural formula of D-3 is as follows:

[0110]

[0111] The chemical reaction equations in this preparation method are as follows:

[0112]

[0113] Example 5

[0114] S5. Preparation of intermediate DCN-Br

[0115] 3-Bromo-9,10-phenanthrenequinone (858 mg, 3 mmol) and 4,5-diaminophthalonitrile (521.4 mg, 3.3 mmol) were added to a 50 mL single-necked flask, followed by the addition of 20 mL of acetic acid. The mixture was heated at 120 °C. After cooling to room temperature, the resulting mixture was poured into water and then filtered. The solid was washed several times with water and methanol. 1040 mg of a yellow solid was obtained, with a yield of 85%. No further purification was required, and the next reaction was carried out directly. Due to the extremely poor solubility of DCN-Br, its carbon and hydrogen spectra could not be obtained. The structural formula of DCN-Br is as follows:

[0116]

[0117] The chemical reaction equations in this preparation method are as follows:

[0118]

[0119] Example 6

[0120] S6. Target product DCN-SPBu

[0121] D-3 (201 mg, 0.187 mmol), DCN-Br (61 mg, 0.15 mmol), tetraphenylphosphine palladium (12 mg, 0.01 mmol), and potassium carbonate (77 mg, 0.56 mmol) were added to a 50 mL two-necked flask. 10 mL of 1,4-dioxane and 2 mL of deionized water were injected under nitrogen atmosphere, and the reaction was carried out at 95 °C under nitrogen atmosphere for 12 h under reflux. After the reaction, the mixture was extracted successively with saturated brine and ethyl acetate to obtain the upper organic phase, which was then rotary evaporated. The mixture was purified by column chromatography using dichloromethane:petroleum ether in a 1:3 ratio as the developing solvent, finally yielding 134 mg of DCN-SPBu (purple solid) (yield: 55%). The structural formula of DCN-SPBu is as follows:

[0122]

[0123] The chemical reaction equations in this preparation method are as follows:

[0124]

[0125] Characterization and performance testing

[0126] The compounds prepared in Example 6 were characterized and their performance was tested. The results are as follows: Figures 1-9 As shown.

[0127] Figure 1The proton NMR spectrum of the compound DCN-SPBu prepared for this patent application was measured using a Bruker 400MHz superconducting NMR spectrometer, with deuterated chloroform as the solvent. Figure 1 It can be seen that its characteristic wavenumber (ppm) is 1 H NMR (500MHz, CDCl3) δ9.29 (dd, J=13.0, 8.3Hz, 2H), 8.80–8.56 (m, 4H), 7.90 (d d,J=15.5,7.8Hz,2H),7.85–7.75(m,1H),7.67(d,J=7.4Hz,2H),7.59(d,J=8.2 Hz,2H),7.54(d,J=8.5Hz,1H),7.42–7.37(m,4H),7.36–7.32(m,2H),7.27–7. 20(m,12H),7.10(t,J=9.2Hz,10H),7.04(dd,J=8.1,2.2Hz,1H),1.28(s,36H). The integrated value of the proton NMR spectrum is basically consistent with the theoretical value of the target luminescent molecule, confirming the availability of the near-infrared material DCN-SPBu suitable for solution processing. Furthermore, the peak energies in the proton NMR spectrum correspond one-to-one with the hydrogen atoms of the DCN-SPBu molecule, indicating a reasonable number and successful synthesis of DCN-SPBu with a simple structure and high purity.

[0128] Figure 2 This is the HRMS (high-resolution mass spectrum) of the compound DCN-SPBu prepared in Example 6. Calculations show that the theoretical value for DCN-SPBu, a near-infrared material suitable for solution processing, is 1277.63355. However, mass spectrometry measurements show the actual [M+H] value... + Value: 1278.64075, further proving that the compound prepared in Example 6 is a near-infrared material compound DCN-SPBu suitable for solution processing.

[0129] Figure 3 The image shows the normalized absorption spectrum and fluorescence emission spectrum of the near-infrared material DCN-SPBu in toluene solution, measured by a Shimadzu UV-2700 UV-Vis spectrophotometer. Figure 3 As can be seen from the data, the intramolecular charge transfer absorption peak of the near-infrared material DCN-SPBu, which is suitable for solution processing, in the ultraviolet-visible absorption spectrum of toluene solution is mainly at 525 nm, while the emission in toluene solution is around 670 nm, which belongs to deep red light.

[0130] Figure 4 The image shows the temperature-dependent transient fluorescence spectrum of the near-infrared material DCN-SPBu prepared under nitrogen atmosphere from 100K to 300K. (From...) Figure 4As can be seen, the delayed fluorescence component increases with the increase of ambient temperature, which shows that the molecule has thermally activated delayed fluorescence properties.

[0131] Figure 5 This is the fluorescence emission spectrum of the near-infrared material DCN-SPBu prepared in this patent application in solutions of hexane, toluene, and dioxane. Figure 5 As shown, the fluorescence emission peaks of DCN-SPBu in hexane, toluene, and dioxane solutions are 589 nm, 668 nm, and 713 nm, respectively, and a red shift occurs with increasing polarity.

[0132] Figure 6 The near-infrared material DCN-SPBu prepared in this patent application was subjected to a nitrogen atmosphere at 10°C / min. -1 The TGA curve was obtained by measuring the heating rate. From Figure 6 It can be seen that this molecule has good thermal stability and can be used for traditional device fabrication.

[0133] Figure 7 This is a brightness-voltage-current density diagram of the near-infrared material DCN-SPBu doped with 15wt% in a CBP thin film prepared according to this patent application.

[0134] Figure 8 EQE-brightness diagram of the near-infrared material DCN-SPBu doped with 15 wt% in a CBP thin film prepared for this patent application. Figure 8 It can be seen that the maximum external quantum efficiency of the fabricated device is 8.33%.

[0135] Figure 9 The EL spectrum of the near-infrared material DCN-SPBu prepared for this patent application. Figure 9 It can be seen that the emission wavelength of this device is around 700nm, which is near-infrared red light emission.

[0136] The near-infrared material suitable for solution processing disclosed in this patent application consists of a rigid electron acceptor fragment and a bulky electron donor fragment (N-(9,9-bis(4-(tert-butylphenyl)-9H-fluoren-2-yl)amino)-9,9-bis(4-(tert-butylphenyl))-N-phenyl-9H-fluoren-2-amine), wherein the electron acceptor fragment is diphenyl[a,c]phenazine-11,12-dinitrile. This material is a near-infrared material with thermally activated delayed fluorescence properties, and the fabricated device has a maximum external quantum efficiency of 8.33%.

[0137] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this patent application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0138] Although several embodiments of this patent application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this patent application, the scope of which is defined by the claims and their equivalents.

Claims

1. A near-infrared material suitable for solution processing, characterized in that, The structure of the near-infrared material suitable for solution processing has a molecular structure as shown below: 。 2. The method of claim 1 for the preparation of near infrared materials suitable for solution processing, characterized in that, The method comprises the following steps: S1. Preparation of intermediate D-0 Methyl o-bromobenzoate, p-chloroboric acid, tetraphenylphosphine palladium, potassium carbonate were put into two-mouth flasks, 1,4-dioxane and deionized water were injected under the condition of nitrogen atmosphere, and the reaction was carried out under the condition of inert gas atmosphere, the reaction was refluxed, and after the reaction, saturated brine and ethyl acetate were used for extraction in sequence, the upper organic phase was obtained, rotary evaporation was carried out, and finally column chromatography purification was carried out, finally the intermediate D-0 was obtained, and the structure is as shown below: ； S2. Preparation of intermediate D-1 4-tert-Butyl phenyl magnesium bromide and D-0 were injected into two-mouth flasks filled with inert gas atmosphere in sequence, the obtained mixture was refluxed and stirred under the condition of 50 DEG C, after the reaction was completed, the cooled reaction mixture was quenched with saturated ammonium chloride solution, saturated brine and dichloromethane were used for extraction in sequence, the lower organic phase was obtained, rotary evaporation was carried out, after the solvent was rotary evaporated, acetic acid and hydrochloric acid were added, the reaction was refluxed, after the reaction was completed, the cooled reaction mixture was quenched with water, the precipitate was filtered, washed with methanol and dried, finally 9,9-bis (4- (tert-butyl) phenyl) -2-chloro-9H-fluorene D-1 was obtained, and the structure is as shown below: ； S3. Preparation of intermediate D-2 D-1, p-chloroaniline, palladium acetate, tri-tert-butyl phosphine, potassium tert-butoxide were sequentially put into a 50ml two-mouth flask, toluene was injected under the condition of nitrogen atmosphere, and the reaction was carried out under the condition of inert gas atmosphere and 110 DEG C, the reaction was refluxed for 24h, after the reaction, saturated brine and dichloromethane were used for extraction in sequence, the lower organic phase was obtained, rotary evaporation was carried out, and finally column chromatography purification was carried out, finally D-2 was obtained, and the structure is as shown below: ； S4. Preparation of intermediate D-3 D-2, pinacol diboronic acid, dibenzylideneacetone palladium, potassium acetate, 2-bicyclohexyl phosphine-2', 4', 6'-triisopropyl biphenyl were put into a 50ml two-mouth flask, 1,4-dioxane 10ml was injected under the condition of nitrogen atmosphere, and the reaction was carried out under the condition of nitrogen atmosphere, then saturated brine and ethyl acetate were used for extraction, the upper organic phase was obtained, rotary evaporation was carried out, and finally column chromatography purification was carried out, finally the intermediate D-3 was obtained, and the structure is as shown below: ； S5. Preparation of intermediate DCN-Br 3-bromo-9,10-phenanthrenequinone and 4,5-diamino phthalonitrile were put into a single-mouth flask, 20ml acetic acid was added, heating was carried out under the condition of 120 DEG C, after cooling to room temperature, the obtained mixture was poured into water, then filtration was carried out, the solid was washed with water and methanol, and yellow solid intermediate DCN-Br was obtained, and the structure is as shown below: ； S6. Preparation of target product DCN-SPBu D-3, DCN-Br, tetrakis triphenylphosphine palladium, potassium carbonate were put into a 50ml two-mouth flask, 1, 4-dioxane 10ml and deionized water 2ml were injected under the nitrogen environment, and the reaction was carried out under the condition of nitrogen environment and 95℃, the reaction reflux time was 12h, after the reaction, saturated brine and ethyl acetate were used for extraction in turn, the upper organic phase was obtained, rotary evaporation was carried out, and finally column chromatography purification was carried out, finally the target product DCN-SPBu was obtained, and its structural formula is as follows: 。 3. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, The molar ratio of the methyl o-bromobenzoate and the p-chlorobenzoic acid in the step S1 is 1:1.

2.

4. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, The molar ratio of the 4-tert-butyl phenyl magnesium bromide and D-0 in the step S2 is 4:

1.

5. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, The molar ratio of the intermediate D-1, p-chloroaniline, tri-tert-butyl phosphine and potassium tert-butoxide in the step S3 is 1:0.45:0.09:4.

5.

6. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, In the step S1, the temperature was heated to 100℃ for reaction, and the reaction time was 12h.

7. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, In the step S2, acetic acid 15ml and hydrochloric acid 2ml were added, and the reaction was carried out at 125℃, and the reaction reflux time was 4h.

8. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, The inert gas environment in the steps S1, S2 and S3 was realized by first vacuumizing the reaction device and then filling with high-purity nitrogen or argon.

9. The method for preparing near-infrared materials suitable for solution processing according to claim 2, characterized in that, The step S4 was carried out under the condition of nitrogen environment and 100℃, and the reaction reflux time was 12h.

10. Use of the near-infrared material suitable for solution processing of claim 1 in an organic light emitting device, which is prepared by a solution processing method.

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