A polymer with HLCT properties, its preparation method, applications, organic light-emitting diode, and display panel

Abstract

The present invention provides a polymer having HLCT properties, a preparation method, an application, an organic light-emitting diode, and a display panel; the present invention is based on a carbazole-benzophenone system, and by separating with an alkyl chain to achieve different conjugation degrees, polymers with different conjugation degrees are synthesized. Such polymers have excellent HLCT properties and have good application prospects in the field of luminescent materials. In addition, by changing the conjugation degree of the synthesized polymer, the light color of the polymer's luminescence can be adjusted. Such polymers can be used to prepare OLED devices with different light colors, and the polymer has good solubility in various common solvents, which is very conducive to preparing OLED devices by solution method, and the cost of manufacturing OLED devices is relatively low.

Description

Technical Field

[0001] The present invention relates to the technical field of organic light-emitting materials, and in particular, to a polymer having HLCT properties, a preparation method thereof, an application thereof, an organic light-emitting diode, and a display panel. Background Art

[0002] In recent years, organic light-emitting diodes (OLEDs) have made great progress in the fields of lighting and display due to their unique properties and advantages. However, currently, blue OLEDs are still at a disadvantage in the entire spectrum, severely restricting the development of OLEDs. Therefore, it is very important to develop high-performance blue light materials.

[0003] Early blue OLED materials were mainly fluorescent materials, but their theoretical quantum efficiency was only 25%, and the exciton utilization rate was relatively low. Until the emergence of the second-generation phosphorescent materials, a theoretical quantum efficiency of 100% was achieved. However, phosphorescent materials often require the participation of noble metals to enhance the orbital coupling strength, which not only increases costs but also easily causes environmental pollution. The third-generation thermally activated delayed fluorescence (TADF) materials solve the problem of noble metals and can also achieve 100% exciton utilization rate. However, devices based on TADF materials often require host doping and have a relatively serious efficiency roll-off. Therefore, it is very important to explore new luminescent layer materials.

[0004] Materials with hybrid local excitation and charge transfer (HLCT) properties, similar to materials with TADF properties, can both achieve a quantum efficiency of 100%. In recent years, scholars have conducted extensive research on materials with HLCT properties. Materials with HLCT properties can not only effectively improve the device efficiency but also have relatively stable device performance, with a smaller device efficiency roll-off. Due to their significant resource advantages and low cost, HLCT materials have become strong competitors for the luminescent layer materials of organic light-emitting diodes (OLEDs). However, currently, the discovered HLCT materials are few, and their performance also needs to be improved. HLCT materials suitable for wet-processed OLED devices are urgently needed to be developed. Summary of the Invention

[0005] The technical problem solved by the present invention is that currently, the discovered HLCT materials are few, their performance also needs to be improved, and HLCT materials suitable for wet-processed OLED devices are urgently needed to be developed.

[0006] To solve the above technical problem, the technical solution adopted by the present invention is as follows:

[0007] A polymer having HLCT properties, the polymer having a structure shown in the following formula (1),

[0008]

[0009] Among them, x and n are integers greater than or equal to 1, m is an integer greater than or equal to 2. When n is 1, R has the structure shown in the following formula (2):

[0010]

[0011] When n is greater than or equal to 2, R has the structure shown in the following formula (3):

[0012]

[0013] Preferably, x in the polymer is 1 - 10.

[0014] Preferably, the energy difference ΔE between the lowest triplet state and the lowest singlet state of the polymer st > 0.3 eV

[0015] The present invention also provides a preparation method of a polymer with HLCT properties. Based on the polymer with HLCT properties described above, and in the molecular structural formula of the polymer with HLCT properties, n is 1 and x is 10. The preparation method of the polymer with HLCT properties includes: under the protection of inert gas, mixing compound model, compound A7, tetrakis(triphenylphosphine)palladium, potassium carbonate, ultra - dry THF and water, and heating for reaction; sequentially carrying out sedimentation, filtration, extraction and drying on the reaction mixture to obtain a polymer with HLCT properties; wherein, compound model and compound A7 respectively have the structures shown in formula (4) and formula (5):

[0016]

[0017] The present invention also provides a preparation method of a polymer with HLCT properties. Based on the polymer with HLCT properties described above, and in the molecular structural formula of the polymer with HLCT properties, n is 2 and x is 10. The preparation method of the polymer with HLCT properties includes: mixing bis(1,5 - cyclooctadiene)nickel(0), 1,5 - cyclooctadiene, 2,2'-bipyridine and ultra - dry DMF in a first polymerization tube, heating and stirring; mixing compound model and ultra - dry THF in a second polymerization tube; transferring the solution in the second polymerization tube to the first polymerization tube, heating for reaction; sequentially carrying out sedimentation, filtration, extraction and drying on the reaction mixture to obtain a polymer with HLCT properties; wherein, compound model has the structure shown in formula (4):

[0018]

[0019] The present invention also provides a method for preparing a polymer with HLCT properties. Based on the polymer with HLCT properties as described above, and in the molecular structural formula of the polymer with HLCT properties, n is 3 and x is 10. The method for preparing the polymer with HLCT properties includes: under the protection of an inert gas, mixing compound model, compound A9, tetrakis(triphenylphosphine)palladium, potassium carbonate, ultra-dry THF and water, and heating for reaction; successively carrying out sedimentation, filtration, extraction and drying on the reaction mixture to obtain a polymer with HLCT properties; wherein, compound model and compound A9 respectively have the structures shown in formula (4) and formula (6):

[0020]

[0021]

[0022] The present invention also provides the application of the polymer with HLCT properties as described above as a luminescent material.

[0023] The present invention further provides an organic light-emitting diode, including: an anode and a cathode, and at least one light-emitting layer located between the anode and the cathode, and the light-emitting layer includes at least one polymer with HLCT properties as described above.

[0024] Preferably, the cathode includes one of a conductive metal and a metal oxide, and the anode includes one of conductive glass.

[0025] The present invention further provides a display panel, including the organic light-emitting diode as described above.

[0026] Compared with the prior art, the present invention is based on carbazole and benzophenone, and realizes different degrees of conjugation through the separation of alkyl chains, synthesizes polymers with different degrees of conjugation. The repeating units of this type of polymer all have the common structure of carbazole-benzophenone-carbazole, and the carbonyl groups existing on the main chain of the polymer change the electron cloud distribution of the molecule, making the polymer have excellent HLCT properties and having good application prospects in the field of luminescent materials. In addition, by changing the degree of conjugation of the synthesized polymer, the light color of the polymer luminescence can be adjusted. This type of polymer can be used to prepare OLED devices with different light colors, and the polymer has good solubility in various common solvents, which is very conducive to preparing OLED devices by solution method, and the cost of making OLED devices is relatively low. Description of the Drawings

[0027] Figure 1 It is the general structural formula of the polymer with HLCT properties synthesized in the embodiment of the present invention;

[0028] Figure 2 UV-visible absorption spectra of the synthesized polymers PZ1, PZ2, and PZ3 in toluene and in the thin film state at room temperature in the embodiments of the present invention;

[0029] Figure 3 Fluorescence spectra of the synthesized polymers PZ1, PZ2, and PZ3 in toluene and in the thin film state at room temperature in the embodiments of the present invention;

[0030] Figure 4 Fluorescence and phosphorescence spectra of the synthesized polymer PZ1 at a temperature of 77K in the embodiments of the present invention;

[0031] Figure 5 Fluorescence and phosphorescence spectra of the synthesized polymer PZ2 at a temperature of 77K in the embodiments of the present invention;

[0032] Figure 6 Fluorescence and phosphorescence spectra of the synthesized polymer PZ3 at a temperature of 77K in the embodiments of the present invention;

[0033] Figure 7 Lippert-Mataga model diagrams of the synthesized polymer PZ1 in solvents with different polarities in the embodiments of the present invention;

[0034] Figure 8 Lippert-Mataga model diagrams of the synthesized polymer PZ2 in solvents with different polarities in the embodiments of the present invention;

[0035] Figure 9 Lippert-Mataga model diagrams of the synthesized polymer PZ3 in solvents with different polarities in the embodiments of the present invention;

[0036] Figure 10 Transient photoluminescence decay spectra of the synthesized polymer PZ1 in the embodiments of the present invention;

[0037] Figure 11 Transient photoluminescence decay spectra of the synthesized polymer PZ2 in the embodiments of the present invention;

[0038] Figure 12 Transient photoluminescence decay spectra of the synthesized polymer PZ3 in the embodiments of the present invention;

[0039] Figure 13 Natural transition orbital distribution diagrams of the synthesized polymer PZ1 in the embodiments of the present invention;

[0040] Figure 14 Natural transition orbital distribution diagrams of the synthesized polymer PZ2 in the embodiments of the present invention;

[0041] Figure 15 : is the natural transition orbital distribution diagram of the polymer PZ3 synthesized in the embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0043] It should be noted that, in the absence of conflict, the features in the embodiments of the present invention can be combined with each other. The meanings of the terms "comprising", "including", "containing", and "having" are non-restrictive, and other steps and other ingredients that do not affect the results can be added. The above terms cover the terms "consisting of..." and "essentially consisting of...". Unless otherwise specified, materials, equipment, and reagents are commercially available. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0044] Except as indicated in the operating examples, or where otherwise indicated, all numbers used in the specification and claims expressing quantities of ingredients, physicochemical properties, and the like are to be understood as being modified in all instances by the term "about." For example, therefore, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and the appended claims are approximate values, which those skilled in the art will be able to appropriately vary in order to obtain the desired properties sought to be obtained utilizing the teachings disclosed herein.

[0045] An embodiment of the present invention provides a polymer having HLCT properties, wherein the polymer has a structure shown in the following formula (1):

[0046]

[0047] Wherein, x and n are integers greater than or equal to 1, m is an integer greater than or equal to 2, and when n is 1, R has the structure shown in the following formula (2):

[0048]

[0049] When n is greater than or equal to 2, R has the structure shown in the following formula (3):

[0050]

[0051] Compared with the prior art, the present invention is based on carbazole and benzophenone, and realizes different degrees of conjugation through the separation of alkyl chains, synthesizing polymers with different degrees of conjugation. The repeating units of such polymers all have the common structure of carbazole-benzophenone-carbazole, and the carbonyl groups present on the main chain of the polymer change the electron cloud distribution of the molecule, endowing the polymer with excellent HLCT properties and having good application prospects in the field of luminescent materials. In addition, the polymer has good solubility in various common solvents, which is very conducive to the preparation of OLED devices by solution methods, and the cost of fabricating OLED devices is relatively low.

[0052] In the examples of the present invention, the degree of conjugation of the synthesized polymer increases with the increase of n, and both the ultraviolet-visible absorption spectrum and the fluorescence spectrum of the polymer show red shifts.

[0053] Exemplarily, when n is 1 and x takes values from 1 to 10, the polymers respectively have the following structural formulas:

[0054]

[0055]

[0056] Exemplarily, when n is 2 and x takes values from 1 to 10, the polymers respectively have the following structural formulas:

[0057]

[0058]

[0059] Exemplarily, when n is 3 and x takes values from 1 to 10, the polymers respectively have the following structural formulas:

[0060]

[0061]

[0062] The examples of the present invention also provide the application of the above-mentioned polymer as a luminescent material.

[0063] The examples of the present invention also provide an organic electroluminescent device, including: an anode and a cathode, and at least one light-emitting layer located between the anode and the cathode, the light-emitting layer including at least one of the above-mentioned polymers having HLCT properties.

[0064] The anode includes conductive glass. Exemplarily, such as ITO or FTO conductive glass.

[0065] The cathode may include a conductive metal or a metal oxide. The cathode can easily inject electrons into the EIL or ETL or directly into the light-emitting layer. In principle, all materials that can be used as the cathode of an OLED may be used as the cathode material of the organic electroluminescent device of the present invention. The cathode material includes one of Al, Au, and Ag.

[0066] The organic electroluminescent device includes one of an organic light-emitting diode, an organic photovoltaic cell, an organic light-emitting battery, an organic field-effect transistor, an organic light-emitting field-effect transistor, an organic laser, an organic spintronic device, an organic sensor, and an organic plasmon-emitting diode.

[0067] An embodiment of the present invention further provides a display panel, including the organic light-emitting diode as described above.

[0068] Taking n as 1, 2, and 3 respectively, and x as 10 as an example, the synthesis methods of three polymers with different degrees of conjugation are introduced as follows:

[0069] Example 1. Preparation of reactants required for synthesizing three polymers PZ1, PZ2, and PZ3 with different degrees of conjugation

[0070] 1.1 Synthesis of Compound A1

[0071] Add carbazole (12.54 g, 9.75 mmol), 11-chlorododecyl-11-enoyl chloride (5.01 g, 18.75 mmol), and aluminum trichloride (7.50 g, 56.25 mmol) into a 500 ml three-necked flask. Evacuate and replace with nitrogen three times, then add 250 ml of ultra-dry dichloromethane (DCM) solvent to the three-necked flask, and stir at 0 °C for 24 h; after the reaction is completed, cool to room temperature, add it to 200 ml of water, extract with ethyl acetate (EA), spin-dry the organic phase, and purify by column chromatography to obtain 11.40 g of white solid compound A1, with a yield of 65%; among them, the eluent used for purification by column chromatography is a mixture of petroleum ether and dichloromethane with a volume ratio of 3:1. The reaction formula for the synthesis of compound A1 is as follows:

[0072]

[0073] The characterization data of compound A1 are as follows: 1 H NMR (400 MHz, CDCl3) δ 8.74 (s, 2H), 8.38 - 7.88 (m, 8H), 7.42 (dt, J = 19.8, 8.7 Hz, 6H), 1.57 (s,, 20H). TOF-MS: 529.2866 (measured value), 528.6960 (calculated value).

[0074] 1.2 Synthesis of Compound A2

[0075] Compound A1 (3.00 g, 6.00 mmol) and N-bromosuccinimide (2.60 g, 14.30 mmol) were added to a 250 ml three-necked flask. Then, 80 ml of chloroform and 80 ml of glacial acetic acid were respectively added to the three-necked flask. The mixture was stirred at room temperature in the dark for 6 h. After the reaction was completed, the reaction mixture was added to 200 ml of water and extracted with dichloromethane (DCM). After the organic phase was dried by evaporation, it was purified by column chromatography to obtain 3.00 g of white solid compound A2, with a yield of 100%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 7:3. The reaction formula for the synthesis of compound A2 is as follows:

[0076]

[0077] The characterization data of compound A2 are as follows: 1 H NMR (400 MHz, CDCl3) δ 8.14 (d, J = 1.7 Hz, 4H), 8.11 (s, 2H), 7.52 (dd, J = 8.6, 1.9 Hz, 4H), 7.32 (d, J = 8.6 Hz, 4H), 1.53 (s, 10H), 1.25 (s, 10H). TOF-MS: 687.1055 (measured value), 686.4880 (calculated value).

[0078] 1.3 Synthesis of compound A3

[0079] Carbazole (12.54 g, 9.75 mmol), 11-chlorododec-11-enoyl chloride (10.02 g, 37.15 mmol) and aluminum trichloride (7.50 g, 56.25 mmol) were added to a 500 ml three-necked flask. The flask was evacuated and replaced with nitrogen three times. Then, 250 ml of ultra-dry dichloromethane (DCM) solvent was added to the three-necked flask, and the mixture was stirred at 0 °C for 24 h. After the reaction was completed, it was cooled to room temperature. The reaction mixture was added to 200 ml of water and extracted with ethyl acetate (EA). After the organic phase was dried by evaporation, it was purified by column chromatography to obtain white solid powder compound A3, with a yield of 53%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 3:1. The reaction formula for the synthesis of compound A3 is as follows:

[0080]

[0081] The characterization data of compound A3 are as follows: 11H NMR (400 MHz, CDCl3) δ 8.87 (s, 1H), 8.79 (s, 2H), 8.14 (dd, J = 8.5, 1.1 Hz, 2H), 7.49 (d, J = 8.5 Hz, 2H), 3.11 (t, J = 7.4 Hz, 4H), 1.91 - 1.73 (m, 4H), 1.53 - 1.10 (m, 32H), 0.91 - 0.80 (m, 6H). TOF-MS: 532.4158 (measured), 531.8250 (calculated).

[0082] 1.4、Synthesis of Compound A4

[0083] Aluminum chloride (2.51 g, 18.81 mmol) was added to a 500 ml three-necked flask, and then the flask was evacuated and filled with nitrogen three times. Then, 100 ml of ultra-dry tetrahydrofuran (THF) was added to the three-necked flask, and then lithium aluminum hydride (15.04 ml, 37.61 mmol) was slowly injected into the three-necked flask. Compound A3 (5.00 g, 9.40 mmol) and 100 ml of ultra-dry tetrahydrofuran (THF) were added to a 250 ml constant pressure dropping funnel connected to the three-necked flask. The constant pressure dropping funnel was opened to slowly drip the solution into the three-necked flask, and the mixture was stirred at 0 °C in the dark for 24 h. After the reaction was completed, the solution was sucked out and dropped into ethyl acetate at 0 °C. Then, dilute hydrochloric acid was added to dissolve the precipitate, and the mixture was added to 200 ml of water for extraction. After the organic phase was dried by evaporation, it was purified by column chromatography to obtain 3.60 g of white solid compound A4 with a yield of 76%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 8:2. The reaction formula for the synthesis of compound A4 is as follows:

[0084]

[0085] Characterization data of compound A4 are as follows: 1 1H NMR (400 MHz, CDCl3) δ 7.90 - 7.74 (m, 3H), 7.29 (t, J = 7.4 Hz, 2H), 7.22 (dd, J = 8.2, 1.4 Hz, 2H), 2.88 - 2.54 (m, 4H), 1.80 - 1.58 (m, 4H), 1.49 - 1.14 (m, 36H), 0.88 (t, J = 6.8 Hz, 6H). TOF-MS: 504.4575 (measured), 503.8590 (calculated).

[0086] 1.5、Synthesis of Compound A5

[0087] Compound A4 (9.00 g, 17.80 mmol), bis(4-fluorophenyl)methanone (5.80 g, 21.40 mmol) and cesium carbonate (7.50 g, 23.14 mmol) were added to a 500 ml three-necked flask. The flask was evacuated and refilled with nitrogen three times. Then, 300 ml of ultra-dry dimethyl sulfoxide (DMSO) was added to the three-necked flask, and the reaction was carried out at 110 °C for 24 h. After the reaction was completed, the reaction mixture was added to 200 ml of water, extracted with ethyl acetate. After the organic phase was dried by evaporation, it was purified by column chromatography to obtain 7.21 g of a yellow oily compound A5, with a yield of 49%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 9:1. The reaction formula for the synthesis of compound A5 is as follows:

[0088]

[0089] The characterization data of compound A5 are as follows: 1 H NMR (400 MHz, CDCl3) δ 8.02 (d, J = 8.4 Hz, 2H), 7.94 (dd, J = 9.4, 6.3 Hz, 4H), 7.73 (d, J = 8.4 Hz, 2H), 7.47 - 7.41 (m, 2H), 7.23 (dd, J = 10.1, 7.0 Hz, 4H), 2.80 (t, J = 7.7 Hz, 4H), 1.80 - 1.65 (m, 4H), 1.31 (d, J = 39.7 Hz, 36H), 0.88 (t, J = 6.7 Hz, 6H). TOF-MS: 702.5077 (measured value), 702.0554 (calculated value).

[0090] 1.6. Synthesis of compound model

[0091] Compound A2 (9.00 g, 17.80 mmol), compound A5 (5.80 g, 21.40 mmol) and cesium carbonate (7.50 g, 23.14 mmol) were added to a 500 ml three-necked flask. The flask was evacuated and refilled with nitrogen three times. Then, 300 ml of ultra-dry dimethyl sulfoxide (DMSO) was added to the three-necked flask, and the reaction was carried out at 110 °C for 24 h. After the reaction was completed, the reaction mixture was added to 200 ml of water, extracted with ethyl acetate. After the organic phase was dried by evaporation, it was purified by column chromatography to finally obtain a yellow solid compound model, with a yield of 46%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 9:1. The reaction formula for the synthesis of compound model is as follows:

[0092]

[0093] The characterization data of compound model are as follows: 11H NMR (400 MHz, CD2Cl2) δ 8.78 (s, 1H), 8.42 - 8.37 (m, 2H), 8.16 (dd, J = 15.3, 5.4 Hz, 9H), 7.95 (s, 4H), 7.85 - 7.75 (m, 8H), 7.63 - 7.55 (m, 4H), 7.54 - 7.44 (m, 7H), 7.29 (d, J = 8.4 Hz, 5H), 3.12 (t, J = 7.4 Hz, 4H), 2.85 - 2.77 (m, 8H), 1.84 - 1.69 (m, 12H), 1.38 (s, 24H), 1.26 (d, J = 14.8 Hz, 60H), 0.88 (t, J = 6.8 Hz, 12H). TOF-MS: 2051.0502 (measured), 2050.5860 (calculated).

[0094] 1.7, Synthesis of Compound A6

[0095] p-Hydroxybromobenzene (10.00 g, 57.80 mmol), 1,4-dibromohexane (6.35 g, 26.01 mmol) and potassium carbonate (47.95 g, 346.80 mmol) were added to a 500 ml three-necked flask, and then 300 ml of acetone was added to the three-necked flask. The reaction was refluxed for 24 h; after the reaction was completed, the reaction mixture was added to 200 ml of water, extracted with dichloromethane, the organic phase was dried by evaporation and purified by column chromatography, and then recrystallized with chloroform and ethanol to obtain 15.94 g of white powder compound A6 with a yield of 92%; among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 2:1. The reaction formula for the synthesis of compound A6 is as follows:

[0096]

[0097] The characterization data of compound A6 were: 1H NMR (400 MHz, CDCl3) δ 7.45 - 7.30 (m, 4H), 6.84 - 6.63 (m, 4H), 3.93 (t, J = 6.4 Hz, 4H), 1.99 - 1.68 (m, 4H), 1.61 - 1.36 (m, 4H). TOF-MS: 427.9757 (measured), 425.9830 (calculated).

[0098] 1.8, Synthesis of Compound A7

[0099] Compound A6 (10.00 g, 23.36 mmol), bis(pinacolato)diboron (35.59 g, 140.13 mmol), potassium phosphate (6.88 g, 70.08 mmol) and PdCl2(dppf) (1.71 g, 2.336 mmol) were added to a 500 ml three-necked flask. The flask was evacuated and refilled with nitrogen three times, and then 300 ml of ultra-dry N,N-dimethylformamide (DMF) was added to the three-necked flask. The reaction was carried out at 100 °C for 24 h. After the reaction was completed, the reaction mixture was added to 200 ml of water and extracted with dichloromethane. The organic phase was dried by evaporation and purified by column chromatography. Finally, 7.15 g of white powder compound A7 was obtained with a yield of 59%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 1:1. The chemical name of PdCl2(dppf) is 1,1'-bis(diphenylphosphino)ferrocene palladium chloride, and the reaction formula for the synthesis of compound A7 is as follows:

[0100]

[0101] The characterization data of compound A7 are as follows: 1 1H NMR (400 MHz, CDCl3) δ 7.73 (d, J = 8.5 Hz, 4H), 6.88 (d, J = 8.5 Hz, 4H), 3.99 (t, J = 6.5 Hz, 4H), 1.95 - 1.69 (m, 4H), 1.43 (d, J = 81.5 Hz, 28H). TOF-MS: 523.3350 (measured value), 522.3324 (calculated value).

[0102] 1.9. Synthesis of compound A8

[0103] Compound A5 (9.00 g, 17.8 mmol), 3',6-dibromocarbazole (5.80 g, 21.40 mmol) and cesium carbonate (7.50 g, 23.14 mmol) were added to a 500 ml three-necked flask. The flask was evacuated and refilled with nitrogen three times, and then 300 ml of ultra-dry dimethyl sulfoxide (DMSO) was added to the three-necked flask. The reaction was carried out at 110 °C for 24 h. After the reaction was completed, the reaction mixture was added to 200 ml of water and extracted with ethyl acetate. The organic phase was dried by evaporation and purified by column chromatography. Finally, a yellow solid compound A8 was obtained with a yield of 67%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 9:1. The reaction formula for the synthesis of compound A8 is as follows

[0104]

[0105] The characterization data of compound A8 are as follows: 11H NMR (400 MHz, CDCl3) δ 8.22 (d, J = 1.8 Hz, 2H), 8.16 (t, J = 8.6 Hz, 4H), 7.93 (s, 2H), 7.79 (d, J = 8.5 Hz, 2H), 7.72 (d, J = 8.4 Hz, 2H), 7.56 (dd, J = 8.7, 1.9 Hz, 2H), 7.47 (d, J = 8.4 Hz, 2H), 7.42 - 7.37 (m, 2H), 7.26 (d, J = 2.8 Hz, 1H), 7.24 (d, J = 1.3 Hz, 1H), 2.80 (t, J = 7.7 Hz, 4H), 1.85 - 1.65 (m, 4H), 1.54 - 1.14 (m, 36H), 0.88 (t, J = 6.8 Hz, 6H). TOF-MS: 1007.3716 (measured), 1007.0520 (calculated).

[0106] 1.10. Synthesis of Compound A9

[0107] Compound A8 (6.00 g, 3.97 mmol), bis(pinacolato)diboron (6.10 g, 15.89 mmol), potassium acetate (1.75 g, 11.91 mmol) and PdCl2(dppf) (0.95 g, 0.397 mmol) were added to a 250 ml three-necked flask. The flask was evacuated and filled with nitrogen three times, and then 300 ml of ultra-dry 1,4-dioxane was added. The mixture was heated under reflux for 48 h. After the reaction, the reaction mixture was added to 200 ml of water and extracted with dichloromethane. The organic phase was dried by evaporation and purified by column chromatography. Finally, 3.20 g of white powder compound A9 was obtained with a yield of 52%. Among them, the eluent used for purification by column chromatography was a mixture of petroleum ether and dichloromethane with a volume ratio of 1:2. The reaction formula for the synthesis of compound A9 is as follows:

[0108]

[0109] Characterization data of compound A9: 1 1H NMR (400 MHz, CDCl3) δ 8.69 (d, J = 27.2 Hz, 2H), 8.17 (dd, J = 8.3, 6.6 Hz, 4H), 7.99 - 7.85 (m, 4H), 7.78 (dd, J = 8.3, 6.1 Hz, 4H), 7.60 - 7.28 (m, 6H), 2.89 - 2.69 (m, 4H), 1.81 - 1.58 (m, 8H), 1.45 - 1.37 (m, 24H), 1.26 (s, 32H), 0.87 (t, J = 6.8 Hz, 6H). TOF-MS: 1101.7351 (measured), 1100.7349 (calculated).

[0110] Example 2: Synthesis of Polymer PZ1 when n is 1 and x is 10

[0111] The synthesis reaction uses a Suzuki catalytic system. The specific operation is as follows: In a glove box filled with nitrogen, add compound model (100 mg, 0.025 mmol), compound A7 (12.73 mg, 0.025 mmol), tetrakis(triphenylphosphine)palladium(0) (3.38 mg, 0.003 mmol), potassium carbonate (33.72 mg, 0.025 mmol), 1.6 ml of ultra-dry THF, and 0.4 ml of water into a 10 ml polymerization tube. Then place it in an oil bath at 70 °C and heat for 24 h; after the reaction is completed, dilute the reaction mixture with an appropriate amount of chloroform and back-drip it dropwise with a glass dropper into a 150 ml mixed solution of hydrochloric acid, methanol, and acetone with a volume ratio of 1:1:1, stir for 2 h, filter to collect the solid mixture on the filter paper, and dry it in a vacuum drying oven at 40 °C for 12 h; then, perform Soxhlet extraction with methanol and acetone for 24 h in sequence. Finally, dissolve it with chloroform (purity is HPLC grade) and spin-dry to obtain a yellow powder polymer PZ1 with a yield of 70%. By performing gel permeation chromatography (GPC) on polymer PZ1, the molecular weight (Mw) of polymer PZ1 is 12645, and the polydispersity index (PDI) is 1.58. The reaction formula for the synthesis of polymer PZ1 is as follows:

[0112]

[0113] Example 3: Synthesis of Polymer PZ2 when n is 2 and x is 10

[0114] The synthesis reaction adopted the Yamamoto catalytic system. The specific operation was as follows: In a glove box filled with nitrogen, bis(1,5-cyclooctadiene)nickel(0) (34.0 mg, 0.122 mmol), 1,5-cyclooctadiene (0.10 ml, 0.122 mmol), 2,2'-bipyridine (20.0 mg, 0.122 mmol) and 0.4 ml of ultra-dry DMF were added to a 10-ml polymerization tube C; in another polymerization tube D, compound model (100 mg, 0.025 mmol) and 0.4 ml of ultra-dry THF were added; the polymerization tube C was heated and stirred at 50 °C for 30 min, and then the solution in the polymerization tube D was transferred to the polymerization tube C by syringe, and heated and stirred at 80 °C for 24 h. After the polymerization reaction was completed, the reaction mixture was diluted with an appropriate amount of chloroform and back-dropped with a glass dropper into a 150-ml mixed solution of hydrochloric acid, methanol and acetone with a volume ratio of 1:1:1, stirred for 2 h, the solid mixture on the filter paper was collected by filtration, and dried in a vacuum drying oven at 40 °C for 12 h; then, Soxhlet extraction was carried out with methanol and acetone in turn for 24 h, and finally dissolved with chloroform (purity was HPLC grade) and rotary evaporated to obtain the yellow powder polymer PZ2 with a yield of 75%. By detecting the polymer PZ2 by gel permeation chromatography (GPC), the molecular weight (Mw) of the polymer PZ2 was 11323, and the polydispersity index (PDI) was 1.44. The reaction formula for the synthesis of the polymer PZ2 was as follows:

[0115]

[0116] Example 4. When n is 3 and x is 10, synthesis of polymer PZ3

[0117] The synthesis reaction uses the Suzuki catalytic system. The specific operation is as follows: In a glove box filled with nitrogen, compound model (100 mg, 0.025 mmol), compound A9 (12.73 mg, 0.025 mmol), tetrakis(triphenylphosphine)palladium (3.38 mg, 0.003 mmol), potassium carbonate (33.72 mg, 0.025 mmol), 1.6 ml of ultradry THF and 0.4 ml of water are added to a 10 ml polymerization tube. Then it is placed in an oil bath at 70 °C and heated for 24 h. After the reaction, the reaction mixture is diluted with an appropriate amount of chloroform and back-dropped with a glass dropper into a 150 ml mixture of hydrochloric acid, methanol and acetone with a volume ratio of 1:1:1, stirred for 2 h, and the solid mixture on the filter paper is collected by filtration. It is dried in a vacuum drying oven at 40 °C for 12 h. Finally, it is Soxhlet extracted with methanol and acetone for 24 h in turn, and finally dissolved in chloroform (purity is HPLC grade) and spun dry. Finally, the product obtained is a yellow powder polymer PZ3 with a yield of 80%. By performing gel permeation chromatography (GPC) on polymer PZ3, the molecular weight (Mw) of polymer PZ3 is 37544, and the polydispersity index (PDI) is 2.49. The reaction formula for the synthesis of polymer PZ3 is as follows:

[0118]

[0119] Experimental Example

[0120] It should be noted that in the attached figure, the coordinate axis "normalized PL intensity" is the normalized PL intensity, "normalized PL intensity" is the normalized intensity, "intensity" is the intensity, "wavelength" is the wavelength, and "stokesshift" is the Stokes shift. Figures 13 - 15 Among them, S1 represents the lowest singlet excited state, f is the oscillator strength, and 94.13%, 71.62% and 51.25% are the transition probabilities.

[0121] The polymers PZ1, PZ2 and PZ3 prepared in Examples 2 - 4 are tested for ultraviolet-visible absorption spectra, fluorescence spectra and phosphorescence spectra. The test results are as Figures 1 - 3 shown. Figure 2 are the ultraviolet-visible absorption spectra of polymers PZ1, PZ2 and PZ3 in toluene (shown as PZ1, PZ2 and PZ3 in the figure) and in the thin film state (shown as PZ1', PZ2' and PZ3' in the figure) at room temperature. Figure 3 are the fluorescence spectra of polymers PZ1, PZ2 and PZ3 in toluene (shown as PZ1, PZ2 and PZ3 in the figure) and in the thin film state (shown as PZ1', PZ2' and PZ3' in the figure) at room temperature. Figure 4 , Figure 5 andFigure 6 The fluorescence spectra (PL series in the figure) and phosphorescence spectra (Pho series in the figure) of polymers PZ1, PZ2, and PZ3 at 77 K, respectively. From Figure 2 it can be seen that the absorption around 330 nm of polymers PZ1, PZ2, and PZ3 is π-π* absorption, and the absorption around 420 nm is the absorption of intramolecular charge transfer state (CT). From Figure 3 it can be seen that in toluene, the maximum emission peaks of polymers PZ1 and PZ2 are located at 460 nm for blue light emission. Due to the larger conjugation length, the emission peak of polymer PZ3 is slightly red-shifted to 470 nm emission. The emission peaks of the three polymers in the thin film state are also slightly red-shifted compared to those in toluene. From Figures 4 - 6 the fluorescence spectra and phosphorescence spectra in ST it can be obtained that the ΔE of polymers PZ1, PZ2, and PZ3 are 0.46 eV, 0.41 eV, and 0.43 eV, respectively, which is not conducive to the conversion of triplet excitons to singlet excitons.

[0122] The UV-visible absorption spectra and fluorescence spectra of polymers PZ1, PZ2, and PZ3 prepared in Examples 2-4 were respectively tested in solvents with different polarities: n-hexane, toluene, triethylamine, n-butyl ether, diethyl ether, tetrahydrofuran, dichloromethane, N,N-dimethylformamide (DMF), and acetone. The Lippert-Mataga models of polymers PZ1, PZ2, and PZ3 were obtained by analyzing the measured UV-visible absorption spectra and fluorescence spectra as shown in Figures 7 - 9 respectively. Figures 7 - 9 it can be seen that polymers PZ1, PZ2, and PZ3 exhibit local excited states (LE states) in low-polarity solvents, while they exhibit CT states in high-polarity solvents. All three show non-equivalent hybridization, with low dipoles in low-polarity solvents and high dipoles in high-polarity solvents. It can be seen that polymers PZ1, PZ2, and PZ3 can exhibit both the characteristics of LE states and CT states, and have HCLT properties. In addition, since the UV-visible absorption spectra and fluorescence spectra of polymers PZ1, PZ2, and PZ3 were tested in solvents with different polarities, it shows that polymers PZ1, PZ2, and PZ3 can dissolve well in solvents with different polarities.

[0123] The transient photoluminescence decay spectra of polymers PZ1, PZ2, and PZ3 prepared in Examples 2-4 were respectively tested, and the test results are shown in Figures 10 - 12 respectively. From Figures 10 - 12It can be seen that the exciton lifetimes of polymers PZ1, PZ2, and PZ3 are 2.14 ns, 2.39 ns, and 2.95 ns respectively, and there is no delayed lifetime. Moreover, such short exciton lifetimes do not conform to the characteristics of the exciton lifetimes of TADF materials, further confirming the HLCT properties of polymers PZ1, PZ2, and PZ3.

[0124] Figures 13 - 15 They are respectively the natural transition orbital distribution diagrams of polymers PZ1, PZ2, and PZ3 prepared in Examples 2-4. From Figures 13 - 15 it can be seen that there is a certain degree of overlap between the "holes" and "particles" of polymers PZ1, PZ2, and PZ3, which conforms to the distribution characteristics of HLCT compounds. The degree of overlap of polymer PZ3 is the largest, so the coupling strength is also larger, and the material performance is more excellent.

[0125] In summary, the polymers PZ1, PZ2, and PZ3 prepared in the embodiments of the present invention all have excellent HLCT properties, and these polymers PZ1, PZ2, and PZ3 have good solubility in solvents with different polarities, which is beneficial to the preparation of OLED devices by the solution method and reduces the cost of manufacturing OLED devices. In addition, the conjugation degrees of the polymers PZ1, PZ2, and PZ3 prepared in the embodiments of the present invention increase in sequence. As the conjugation degree of the polymer increases, both the ultraviolet-visible absorption spectrum and the fluorescence spectrum of the polymer show a red shift. Therefore, the light color of the polymer emission can be adjusted by changing the conjugation degree of the synthesized polymer, and thus this type of polymer can be used to prepare OLED devices with different light colors.

[0126] In addition, it should be noted that although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will all fall within the protection scope of the present invention.

Claims

1. A polymer having HLCT properties, characterized in that The polymer has a structure shown in the following formula (1): Wherein, x and n are integers greater than or equal to 1, m is an integer greater than or equal to 2, and when n is 1, R has the structure shown in the following formula (2): When n is greater than or equal to 2, R has the structure shown in the following formula (3): Wherein, x in the polymer is 1-10.

2. The polymer having HLCT properties according to claim 1, characterized in that The difference between the lowest triplet state and the lowest singlet state energy level of the polymer ΔE st >0.3eV.

3. A method for preparing a polymer having HLCT properties, characterized in that: Based on the polymer having HLCT properties according to any one of claims 1 to 2, wherein n is 1 and x is 10 in the molecular structure of the polymer having HLCT properties, the preparation method of the polymer having HLCT properties comprises: under the protection of an inert gas, mixing compound model, compound A7, tetrakistriphenylphosphine palladium, potassium carbonate, ultra-dry tetrahydrofuran and water, and heating to react; after the reaction, sequentially settling, filtering and extracting the mixture, and then drying to obtain a polymer having HLCT properties; wherein compound model and compound A7 have the structures shown in formula (4) and formula (5), respectively:

4. A method for preparing a polymer having HLCT properties, characterized in that: Based on the polymer with HLCT properties according to any one of claims 1 to 2, wherein n is 2 and x is 10 in the molecular structure formula of the polymer with HLCT properties, the preparation method of the polymer with HLCT properties comprises: mixing bis(1,5-cyclooctadiene)nickel(0), 1,5-cyclooctadiene, 2,2'-bipyridine and ultra-dry N,N-dimethylformamide in a first polymerization tube, heating and stirring; mixing compound model and ultra-dry tetrahydrofuran in a second polymerization tube; transferring the solution in the second polymerization tube to the first polymerization tube, heating and reacting; and sequentially sedimenting, filtering, extracting and drying the reaction mixture to obtain a polymer with HLCT properties; wherein the compound model has a structure as shown in formula (4):

5. A method for preparing a polymer having HLCT properties, characterized in that: Based on the polymer having HLCT properties according to any one of claims 1 to 2, wherein n is 3 and x is 10 in the molecular structure of the polymer having HLCT properties, the preparation method of the polymer having HLCT properties comprises: under the protection of an inert gas, mixing compound model, compound A9, tetrakistriphenylphosphine palladium, potassium carbonate, ultra-dry tetrahydrofuran and water, and heating the mixture for reaction; and sequentially sedimenting, filtering, extracting and drying the reaction mixture to obtain a polymer having HLCT properties; wherein compound model and compound A9 have the structures shown in formula (4) and formula (6), respectively:

6. Use of the polymer having HLCT properties according to any one of claims 1 to 2 as a luminescent material.

7. An organic light emitting diode, characterized in that: include: An anode, a cathode, and at least one light-emitting layer located between the anode and the cathode, wherein the light-emitting layer comprises at least one polymer having HLCT properties according to any one of claims 1 to 2.

8. The organic light emitting diode according to claim 7, characterized in that: The cathode includes one of a conductive metal and a metal oxide, and the anode includes one of a conductive glass.

9. A display panel, characterized in that: The organic light emitting diode according to claim 8 is included.

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