An orange-red light thermal activation delayed fluorescence material, a preparation method and application thereof

Abstract

The patent application discloses an orange-red light thermal activation delayed fluorescence material and a preparation method and application thereof, and relates to the field of organic luminescent materials. The thermal activation delayed fluorescence orange-red light material is composed of an electron acceptor fragment and two same electron donor fragments (triphenylamine), the electron acceptor fragment is quinoxaline-6,7-dicyanide, and the electron donor fragment is triphenylamine. The material has the thermal activation delayed fluorescence characteristic, and the maximum external quantum efficiency of the prepared device is 23.2%.

Description

TECHNICAL FIELD

[0001] The present patent application relates to the technical field of organic electroluminescent materials, and more particularly to an orange-red light thermally activated delayed fluorescence material, a preparation method and applications thereof. BACKGROUND

[0002] The material prepared based on the thermally activated delayed fluorescence (TADF) mechanism is activated by thermal energy, and through a small single-triplet energy level difference (ΔE ST ), the generated triplet excitons undergo reverse intersystem crossing (RISC) back to the singlet state, and the singlet excitons and triplet excitons are utilized, thereby achieving 100% exciton utilization. The smaller the overlap of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), the smaller the ΔE ST , and generally, the HOMO and LUMO orbital electron clouds are effectively separated by adjusting the angle between the D / A groups to an appropriate range, thereby obtaining a smaller ΔE ST , which is considered as one of the most classic design schemes in TADF material research.

[0003] However, too small HOMO and LUMO overlap will also result in a small fluorescence radiation transition rate of the material, and the energy loss caused by the internal conversion process will have a very obvious effect, thereby resulting in extremely low device efficiency. In addition, for the luminescent materials based on the TADF mechanism, blue light materials and green light materials have developed rapidly, while red / orange-red light materials are relatively lagging behind. Since the long-wavelength emitting material has a smaller energy barrier, according to the energy gap law, this type of material will usually have a more serious vibration coupling, thereby causing a larger non-radiative transition, which seriously affects the device efficiency.

[0004] PATENT APPLICATION CONTENT

[0005] To overcome one of the problems in the prior art, the primary object of the present patent application is to provide an orange-red light thermally activated delayed fluorescence material. The orange-red light thermally activated delayed fluorescence material has a double-channel emission, which helps to promote the intersystem crossing process of excitons, thereby achieving a higher external quantum efficiency.

[0006] Another object of the present patent application is to provide a preparation method of the orange-red light thermally activated delayed fluorescence material.

[0007] Another object of the present patent application is to provide an application of the orange-red light thermally activated delayed fluorescence material in an organic light-emitting device.

[0008] The above objects of the present patent application are achieved by the following technical solutions:

[0009] An orange-red light thermally activated delayed fluorescence material, a structural formula of the orange-red light thermally activated delayed fluorescence material has a molecular structure as shown in the following:

[0010] .

[0011] The patent application also provides a preparation method of the above-mentioned orange-red light thermally activated delayed fluorescence material, comprising the following steps:

[0012] S1. Preparation of intermediate 1

[0013] 2,4-dibromoacetophenone, N-bromosuccinimide are put into a reaction bottle, ethyl acetate is injected in an inert gas environment, then the temperature is heated for reaction; after the reaction is completed, the solvent is directly spin-dried, and finally the intermediate 1 is obtained, and the structure of the intermediate 1 is as shown in the following:

[0014] ;

[0015] S2. Preparation of intermediate 2

[0016] The intermediate 1 and 4,5-diamino phthalonitrile are added to a solvent, and then cetyltrimethylammonium bromide is added, and the obtained mixture is stirred under reflux; after the reaction is completed, it is cooled, the cooled reaction mixture is diluted, the precipitate is filtered, washed and dried, to obtain a red intermediate 2 crude product, and the structure of the intermediate 2 is as shown in the following:

[0017] ;

[0018] S3. Preparation of target product

[0019] The intermediate 2, 4-(diphenylamino) phenylboronic acid, tetrakis triphenylphosphine palladium and potassium carbonate are put into a reaction flask, 1,4-dioxane and deionized water are injected in an inert gas environment, and the reaction is carried out under the conditions of inert gas environment and temperature of 80-100℃, and the reaction is refluxed; after the reaction, the two solvents are extracted in turn, the upper organic phase is obtained, rotary evaporation is carried out, and then column chromatography purification is carried out, to finally obtain the target product.

[0020] Preferably, the molar ratio of 2,4-dibromoacetophenone and N-bromosuccinimide in step S1 is 1:1.1.

[0021] Preferably, the molar ratio of intermediate 1, 4,5-diamino phthalonitrile and cetyltrimethylammonium bromide in step S2 is 1:1.2:0.25.

[0022] Preferably, the molar ratio of intermediate 2, 4-(diphenylamino) phenylboronic acid, tetrakis triphenylphosphine palladium and potassium carbonate in step S3 is 1:2.2:0.1:5.

[0023] Preferably, in the step S1, the temperature is heated to 60°C for reaction, and the reaction time is 12h.

[0024] Preferably, in the step S2, the solvent is water, and the obtained mixture is stirred under reflux for 8h, and finally washed with methanol and dried, and / or; in the step S3, the reaction is carried out at a temperature of 100°C, and the reflux time is 12h.

[0025] Preferably, in the steps S1, S2 and S3, the inert gas environment is achieved by first vacuumizing the reaction device, and then filling with high-purity nitrogen or argon.

[0026] The patent application also provides the application of the above-mentioned orange-red light thermally activated delayed fluorescence material in an organic light-emitting device.

[0027] Compared with the prior art, the patent application has the following beneficial effects:

[0028] The orange-red light thermally activated delayed fluorescence material of the patent application is composed of an electron acceptor fragment and two identical electron donor fragments (triphenylamine), the electron acceptor fragment is quinoxaline-6,7-dicyanide, and the electron donor fragment is triphenylamine. The material has the characteristics of thermally activated delayed fluorescence, and the maximum external quantum efficiency of the prepared device is 23.2%. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The HRMS diagram of the compound QCN-2TPA prepared in the patent application; 1 HMNR diagram;

[0030] Figure 2 The HRMS diagram of the compound QCN-2TPA prepared in the patent application;

[0031] Figure 3 The ultraviolet-visible absorption diagram of the compound QCN-2TPA prepared in the patent application in four different polar solvents;

[0032] Figure 4 The fluorescence emission diagram of the compound QCN-2TPA prepared in the patent application in four different polar solvents;

[0033] Figure 5 The fluorescence emission spectrum of the non-doped thin film of the compound QCN-2TPA prepared in the patent application at an excitation wavelength of 370nm;

[0034] Figure 6The fluorescence emission spectrum of the compound QCN-2TPA prepared for this patent application was obtained by doping CBP at a concentration of 10 wt% and measuring it at an excitation wavelength of 380 nm.

[0035] Figure 7 The temperature-dependent transient fluorescence spectrum from 100K to 300K was measured under nitrogen conditions after the compound QCN-2TPA prepared for this patent application was fabricated into a doped thin film.

[0036] Figure 8 The compound QCN-2TPA prepared for this patent application was subjected to nitrogen atmosphere at 10 °C for min. -1 The TGA curve was obtained by measuring the heating rate;

[0037] Figure 9 EL spectrum of compound QCN-2TPA prepared for this patent application;

[0038] Figure 10 Power efficiency-brightness and EQE-brightness plots of the compound QCN-2TPA prepared for this patent application, doped at 10 wt% in a CBP thin film. Detailed Implementation

[0039] 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.

[0040] It should be noted that:

[0041] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0042] In this patent application, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0043] Unless otherwise specified, the components or preferred components involved in this patent application may be combined with each other to form new technical solutions.

[0044] 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.

[0045] The "range" disclosed in the present patent application can be in the form of a lower limit and an upper limit, which can be one or more lower limits, and one or more upper limits, respectively.

[0046] In the present patent application, unless otherwise specified, each reaction or operation step can be carried out sequentially or in accordance with the sequence. Preferably, the reaction method herein is carried out sequentially.

[0047] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to that described can also be applied in the present patent application.

[0048] The present patent application provides an orange-red light thermally activated delayed fluorescence material, and the structural formula of the orange-red light thermally activated delayed fluorescence material has the molecular structure as shown below:

[0049] .

[0050] The present patent application provides an orange-red light thermally activated delayed fluorescence material. By introducing a rigid structure to design a LUMO-deeper electron acceptor (A) fragment, and connecting it with two identical planar aromatic electron donors (D) fragments with strong electron-donating ability through a π bridge, an orange-red light material with double-channel emission is designed, for example, the blue part in the above structural formula is the electron donor (D) fragment, and the red part is the electron acceptor (A) fragment. This material with double-channel emission helps to promote the intersystem crossing process of excitons, so as to obtain an orange-red light material with high external quantum efficiency of thermally activated delayed fluorescence.

[0051] The present patent application also provides a preparation method of the above-mentioned orange-red light thermally activated delayed fluorescence material. The method comprises the following steps:

[0052] S1. Preparation of intermediate 1

[0053] 2,4-dibromoacetophenone, N-bromosuccinimide are put into a reaction bottle, and ethyl acetate is injected in an inert gas environment, then the temperature is heated for reaction; after the reaction is completed, the solvent is directly spin-dried, and finally the intermediate 1 is obtained, and the structure of the intermediate 1 is as shown below:

[0054] ;

[0055] S2. Preparation of intermediate 2

[0056] The intermediate 1 and 4,5-diamino-phthalonitrile are added into a solvent, then cetyltrimethylammonium bromide is added, and the obtained mixture is stirred under reflux; after the reaction is completed, the cooled reaction mixture is diluted, the precipitate is filtered, washed and dried to obtain a crude product of red intermediate 2, the structure of which is shown below:

[0057] ;

[0058] S3. Preparation of target product

[0059] The intermediate 2, 4-(diphenylamino)phenylboronic acid, tetrakis(triphenylphosphine)palladium and potassium carbonate are put into a reaction flask, 1,4-dioxane and deionized water are injected under an inert gas environment, and the reaction is carried out under the conditions of inert gas environment and temperature of 80-100℃, and the reaction is refluxed; after the reaction, the two solvents are extracted in turn, the upper organic phase is obtained, rotary evaporation is carried out, and then column chromatography purification is carried out to finally obtain the target product.

[0060] In the preparation method of the present application, the molar ratio of 2,4-dibromoacetophenone and N-bromosuccinimide in step S1 is 1:1.1.

[0061] In the preparation method of the present application, the molar ratio of intermediate 1, 4,5-diamino-phthalonitrile and cetyltrimethylammonium bromide in step S2 is 1:1.2:0.25.

[0062] In the preparation method of the present application, the molar ratio of intermediate 2, 4-(diphenylamino)phenylboronic acid, tetrakis(triphenylphosphine)palladium and potassium carbonate in step S3 is 1:2.2:0.1:5.

[0063] In the preparation method of the present application, in step S1, the temperature is heated to 60℃ for reaction, and the reaction time is 12h.

[0064] In the preparation method of the present application, in step S2, the solvent is water, and the obtained mixture is stirred under reflux for 8h, and finally washed with methanol and dried, and / or; in step S3, the reaction is carried out under the condition of temperature of 100℃, and the reflux time is 12h.

[0065] In the preparation method of the present application, the inert gas environment in steps S1, S2 and S3 is realized by first vacuumizing the reaction device, and then filling with high-purity nitrogen or argon.

[0066] The present application also provides the application of the above-mentioned orange-red light thermal activation delayed fluorescence material in an organic light-emitting device.

[0067] The preparation method of the orange-red light-thermal activated delayed fluorescence material compound QCN-2TPA will be described in detail below.

[0068] Example 1

[0069] S1. Preparation of intermediate 1

[0070] 2,4-Dibromoacetophenone (278 mg, 1 mmol), N-bromosuccinimide (195 mg, 1.1 mmol) were added into a 50 ml two-necked flask, and 6 ml of ethyl acetate was injected under a nitrogen environment, and then the temperature was heated to 60°C for reaction, and the reaction time was 12 h. After the reaction, the solvent was directly spin-dried, and finally the intermediate 1: 2-bromo-1-(2,4-dibromo-phenyl)ethanone (yellow oily liquid) (76%) was obtained, which was directly used in the next step reaction. The structure of the intermediate 1 is as follows:

[0071] ;

[0072] The chemical reaction equation in the preparation method is as follows:

[0073] ;

[0074] Example 2

[0075] S2. Preparation of intermediate 2

[0076] Intermediate 1, 2-bromo-1-(2,4-dibromo-phenyl)ethanone (355 mg, 1 mmol) and 4,5-diamino-phthalonitrile (189 mg, 1.2 mmol) were added into 10 ml of water, and then cetyltrimethylammonium bromide (91 mg, 0.25 mmol) was added. The resulting mixture was stirred under reflux for 8 h. After the reaction was completed, the cooled reaction mixture was poured into water, the precipitate was filtered, washed with methanol and dried to obtain a red crude product, intermediate 2, 2-(2,4-dibromo-phenyl)quinoxaline-6,7-dicarbonitrile (QCN-2Br) (85%), which was used without further purification. The structure of the intermediate 2 is as follows:

[0077] .

[0078] The chemical reaction equation in the preparation method is as follows:

[0079] ;

[0080] Example 3

[0081] S3. Preparation of target product QCN-2TPA

[0082] Into a 50 ml two-necked flask, intermediate 2, 2-(2,4-dibromophenyl)quinoxaline-6,7-dicarbonitrile (411 mg, 1 mmol), 4-(diphenylamino)phenylboronic acid (636 mg, 2.2 mmol), tetrakis(triphenylphosphine)palladium (116 mg, 0.1 mmol), potassium carbonate (690 mg, 5 mmol) were added, 1,4-dioxane 15 ml and deionized water 2.5 ml were injected under nitrogen atmosphere, and the reaction was carried out under nitrogen atmosphere at 100°C. The reaction reflux time was 12 h. After the reaction, saturated brine and ethyl acetate were used for extraction in turn, the upper organic phase was obtained, and rotary evaporation was carried out. Column chromatography was carried out with the developing agent of dichloromethane: petroleum ether = 1:1 ratio, and finally 256 mg of QCN-2TPA (red solid) was obtained (yield: 34.5%).

[0083] The chemical reaction equation in this preparation method is as follows:

[0084] ;

[0085] Characterization and performance test

[0086] The compound prepared in Example 3 was characterized and tested for performance, and the results are shown in Figures 1-10 .

[0087] Figure 1 The compound QCN-2TPA prepared in this patent application was tested by a Bruker 400 MHz superconducting nuclear magnetic resonance instrument for hydrogen spectrum, and the solvent was deuterated chloroform. As can be seen from Figure 1 , the characteristic wave number (ppm) is 1 H NMR (400 MHz, Chloroform-d) δ 8.58 (s, 1H), 8.55 (s, 1H), 8.49 (s, 1H), 7.97 (d, J = 8.5 Hz, 1H), 7.77 (dt, J = 4.5, 2.3 Hz, 2H), 7.62–7.55 (m, 2H), 7.33–7.26 (m, 7H), 7.25 (d, J = 1.8 Hz, 1H), 7.19–7.14 (m, 6H), 7.12–7.03 (m, 10H), 7.00–6.95 (m, 2H). The integral value of the hydrogen spectrum is basically the same as the theoretical value of the target luminescent molecule, and the orange-red light-activated delayed fluorescence material QCN-2TPA can be determined. And the wave peaks in the above hydrogen spectrum can be one-to-one corresponding to the hydrogen atoms of QCN-2TPA molecule, the number is reasonable, indicating that QCN-2TPA is synthesized, and the structure is single and the purity is high.

[0088] Figure 2 is the HRMS (high resolution mass spectrum) of the compound QCN-2TPA prepared in Example 3. The theoretical value of the orange-red light thermally activated delayed fluorescence material QCN-2TPA is [M+H] 743.28, and the actual m / z value tested by mass spectrometry is 743.29, further proving that the compound prepared in Example 3 is the orange-red light thermally activated delayed fluorescence material compound QCN-2TPA, and the compound is structurally single and has high purity. + : 743.28, and the actual m / z value tested by mass spectrometry is 743.29, further proving that the compound prepared in Example 3 is the orange-red light thermally activated delayed fluorescence material compound QCN-2TPA, and the compound is structurally single and has high purity.

[0089] Figure 3 is the normalized absorption spectrum of the UV absorption spectrum of the compound QCN-2TPA in four different polarity solvents measured by the Shimadzu UV-2700 ultraviolet visible spectrophotometer. The four different polarity solvents are n-hexane, toluene (Tol), tetrahydrofuran (THF) and ethyl acetate (EA), and the polarity of the above four organic solvents increases in turn. From Figure 3 it can be seen that the UV-visible absorption spectrum of the orange-red light thermally activated delayed fluorescence material QCN-2TPA in organic solvents does not appear a large degree of red shift or blue shift with the increase of the polarity of the organic solvent, that is, the compound represented by formula (I) of the orange-red light thermally activated delayed fluorescence material can realize a wide range of UV-visible absorption.

[0090] Figure 4 is the fluorescence emission spectrum of the compound QCN-2TPA prepared in this patent application in four different polarity solvents. As shown in Figure 4 , the emission of the QCN-2TPA molecule in toluene solution is 582 nm, respectively. From Figure 4 it can be seen that the orange-red light thermally activated delayed fluorescence material shows a more obvious red shift phenomenon with the increase of the polarity of the organic solvent, indicating that the material exists intramolecular charge transfer phenomenon.

[0091] Figure 5 is the fluorescence emission spectrum of the non-doped thin film of the compound QCN-2TPA prepared in this patent application at an excitation wavelength of 370 nm. As shown in Figure 5 , the emission of the QCN-2TPA molecule in the thin film is 630 nm, which is red light emission.

[0092] Figure 6 is the fluorescence emission spectrum of the compound QCN-2TPA prepared in this patent application doped in CBP at a concentration of 10 wt% and tested at an excitation wavelength of 380 nm. From Figure 6 it can be seen that it is doped in CBP at a ratio of 10 wt% to form a thin film, which shows orange-red light emission with an emission wavelength of 582 nm.

[0093] Figure 7 is the temperature-dependent transient fluorescence spectrum of compound QCN-2TPA prepared in this patent application from 100 K to 300 K under nitrogen. The transient fluorescence spectrum is measured by using Edinburgh FLS980 under nitrogen after the molecule QCN-2TPA is prepared into a doped film at a proportion of 10 wt% at an excitation wavelength of 380 nm. From Figure 7 It can be seen from that the delayed fluorescence component increases with the ambient temperature, which shows that the molecule has the property of thermally activated delayed fluorescence.

[0094] Figure 8 is the TGA curve of compound QCN-2TPA prepared in this patent application at a heating rate of 10 ℃ min -1 under nitrogen. From Figure 8 It can be seen that the molecule has good thermal stability and can be prepared into a conventional device.

[0095] Figure 9 is the EL spectrum of the device prepared by doping compound QCN-2TPA prepared in this patent application into CBP at a proportion of 10 wt%. From Figure 9 It can be seen that the emission wavelength of the device is about 600 nm, which is orange-red light emission.

[0096] Figure 10 is the power efficiency-luminance and EQE-luminance diagram of compound 10 wt% QCN-2TPA doped in CBP film prepared in this patent application. From Figure 10 It can be seen that the maximum external quantum efficiency of the prepared device is 23.2%.

[0097] An orange-red thermally activated delayed fluorescence material is provided in this patent application. By introducing a rigid structure to design a LUMO-deeper electron acceptor (A) fragment, and connecting it with two identical planar aromatic electron donors (D) fragments with strong electron-donating ability through a π bridge, an orange-red light material with double-channel emission is designed. This material with double-channel emission helps to promote the intersystem crossing process of excitons, so as to obtain an orange-red thermally activated delayed fluorescence material with high external quantum efficiency.

[0098] The thermally activated delayed fluorescence orange-red light material in this patent application is composed of an electron acceptor fragment and two identical electron donor fragments (triphenylamine), the electron acceptor fragment is quinoxaline-6,7-dicyanide, and the electron donor fragment is triphenylamine. The material has the property of thermally activated delayed fluorescence, and the maximum external quantum efficiency of the prepared device is 23.2%.

[0099] In the description of the specification, reference to "one embodiment", "some embodiments", "an exemplary embodiment", "an example", "a specific example", or "some examples" means that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the disclosure. The appearances of the phrases "in one embodiment", "in some embodiments", "in an exemplary embodiment", "an example", "a specific example", or "some examples" in various places in the specification are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0100] Although several embodiments of the present patent application have been shown and described, it is to be understood that these embodiments are merely exemplary and that other embodiments can be utilized and that modifications in the detailed arrangement and combination of parts, even radical changes, can be undertaken without departing from the intended spirit and scope of the application, which is defined by the following claims.

Claims

1. An orange-red light thermally activated delayed fluorescence material, characterized by, The structural formula of the orange-red light heat-activated delayed fluorescence material has a molecular structure as shown in the following formula: 。 2. The method of claim 1, wherein the orange-red light thermally activated delayed fluorescence material is prepared by the method comprising: The method comprises the following steps: ​ S1. Preparation of intermediate 1 2,4-dibromoacetophenone, N-bromosuccinimide are put into a reaction bottle, ethyl acetate is injected under inert gas environment, then the reaction system is heated for reaction; after the reaction is completed, the solvent is directly spin-dried, and finally intermediate 1 is obtained, and the structure of the intermediate 1 is as shown in the following formula: ； S2. Preparation of intermediate 2 The intermediate 1 and 4,5-diamino phthalonitrile are added to a solvent, then cetyltrimethylammonium bromide is added, and the obtained mixture is stirred under reflux; after the reaction is completed, the cooled reaction mixture is diluted, the precipitate is filtered, washed and dried to obtain a red intermediate 2 crude product, and the structure of the intermediate 2 is as shown in the following formula: ； S3. Preparation of target product The intermediate 2, 4-(diphenylamino) phenylboronic acid, tetrakis triphenylphosphine palladium and potassium carbonate are put into a reaction flask, 1,4-dioxane and deionized water are injected under inert gas environment, and the reaction is carried out under the conditions of inert gas environment and temperature of 80-100℃, and the reaction is refluxed; after the reaction, saturated brine and ethyl acetate are used for extraction in sequence, the upper organic phase is obtained, rotary evaporation is carried out, then column chromatography purification is carried out, and finally the target product is obtained.

3. The method for preparing the orange-red photothermal activated delayed fluorescence material according to claim 2, characterized in that, The molar ratio of 2,4-dibromoacetophenone and N-bromosuccinimide in step S1 is 1:1.

1.

4. The method for preparing the orange-red photothermal activated delayed fluorescence material according to claim 2, characterized in that, The molar ratio of intermediate 1, 4,5-diamino phthalonitrile and cetyltrimethylammonium bromide in step S2 is 1:1.2:0.

25.

5. The method for preparing the orange-red photothermally activated delayed fluorescence material according to claim 2, characterized in that, The molar ratio of intermediate 2, 4-(diphenylamino) phenylboronic acid, tetrakis triphenylphosphine palladium and potassium carbonate in step S3 is 1:2.2:0.1:

5.

6. The method for preparing the orange-red photothermally activated delayed fluorescence material according to claim 2, characterized in that, In step S1, the temperature is heated to 60℃ for reaction, and the reaction time is 12h.

7. The method for preparing the orange-red photothermal activated delayed fluorescence material according to claim 2, characterized in that, In step S2, the solvent is water, and the obtained mixture is stirred under reflux for 8h, and finally washed with methanol and dried.

8. The method for preparing the orange-red photothermal activated delayed fluorescence material according to claim 2, characterized in that, In step S3, the reaction is carried out under the condition of temperature of 100℃, and the reflux time is 12h.

9. The method for preparing the orange-red photothermally activated delayed fluorescence material according to claim 2, characterized in that, The method for realizing the inert gas environment in steps S1 and S3 is to first vacuumize the reaction device, and then fill with high-purity nitrogen or argon.

10. The application of the orange-red light heat-activated delayed fluorescence material in claim 1 in an organic light-emitting device.

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