WO2021017214A1 - Electroluminescent polymer, preparation method and application thereof - Google Patents

Abstract

The present invention discloses an electroluminescent polymer, a preparation method and an application thereof. The method comprises: under protection of inert gas, the polymerization monomer units M1 and M2 and a monomer containing an Ar structure are completely dissolved with a solvent, Suzuki polymerization reaction is conducted by heating under the action of a catalyst and tetraethyl ammonium hydroxide; phenylboronic acid is added, and reaction is conducted at constant temperature; then bromobenzene is added to continue the reaction at constant temperature; the obtained reaction liquid is purified to obtain the target product. The electroluminescent polymer provided by the present invention contains heteroatoms, and can improve the fluorescence quantum yield and the carrier transmission capacity of light-emitting material, which is beneficial for the light-emitting device to obtain high-efficiency and stable performance of the light-emitting device. The electroluminescent polymer provided by the present invention has good solubility, and can be dissolved by the common organic solvent, through spin-coating, ink-jet printing, printing film formation or other methods, the light-emitting layer of the light-emitting diode can be prepared.

Description

A class of electroluminescent polymer and its preparation method and application Technical field

The invention belongs to the technical field of organic optoelectronics, and particularly relates to a type of electroluminescent polymer and its preparation method and application.

Background technique

Organic light-emitting diode (OLED) displays use organic materials as light-emitting materials, the material structure is easy to modify and improve, and the selection range is wide; the driving voltage is low, only 3-12V DC voltage; self-luminous, no backlight is needed; wide viewing angle , Can be close to 180°; fast response speed, up to 1μs level; in addition, it has the advantages of light weight, ultra-thin, large size, flexible panel, easy molding and processing. Due to the numerous advantages of OLED displays, it has received extensive attention from the scientific and industrial circles. Since Kodak in the United States developed OLED devices in 1987, many organizations have invested resources in the development of OLED technology. After decades of rapid development, OLED flat panel display technology is becoming mature and has taken a place in the field of flat panel displays, but it still needs to continue to improve in terms of lifespan, stability, and cost.

Currently, OLED devices are prepared using a vacuum evaporation process, and the equipment is expensive. The low material utilization rate (~20%) keeps the price of OLED products high. Solution processing technology can make up for the shortcomings of vacuum evaporation, and gradually attracts the attention of scientific research institutions and companies. Polymers can form high-quality films and are not easy to crystallize; they can also change the chemical structure, for example, by adjusting the conjugation length, changing the substituents, adjusting the main and side chain structures, and changing the feed ratio. Such as red, green, and blue light emitting in different colors; at the same time, it also has the advantages of solution processing, such as spin coating, inkjet printing, printing, roll-to-roll film formation, and large-size molding.

However, the conjugated polymers used in OLED devices reported in the prior art still have some shortcomings. For example, blue polymers have poor spectral stability, low device efficiency, short device life, or some polymer monomers are difficult to synthesize and are not suitable for large-scale production, which limit their use in solution processable devices. Commercial application; therefore, the market still needs simple synthesis (especially a synthesis method suitable for mass production), good processability (excellent solubility in organic solvents), and good electroluminescence performance. Polymer material. Especially for solution-processable light-emitting diode devices, there is a demand for high-efficiency red, green, and blue polymer materials. Compared with the prior art polymer, it can improve the efficiency of OLED through the active layer.

The purpose of the present invention is to provide a class of electroluminescent polymers whose polymerized monomers M1 or M2 are easy to synthesize and are especially suitable for large-scale production; their polymers have excellent electroluminescence properties; and have excellent solubility in organic solvents It has high carrier mobility and does not have the drawbacks of the prior art as described above. Another object of the present invention is to expand the range of polymer luminescent materials available to those skilled in the art.

The inventors of the present invention have discovered that S,S-dioxo-dibenzothiophene units are a class of blue-light units with excellent performance, which have a higher fluorescence quantum yield; the sulfone group (-SO ₂ -) in the structure is improved The electron affinity and electron mobility of the molecule; sulfur atoms have good oxidation resistance, etc. Among them, polymers containing 3,7 substituted-S,S-dioxo-dibenzothiophene units show superior photoelectric properties . "Journal of Materials Chemistry C" (Journal of Materials Chemistry C,) reported the largest single-layer device with 3,7-S,S-dioxo-dibenzothiophene units introduced into the polyfluorene backbone as the light-emitting layer. The lumen efficiency is as high as 7.1cd/A, and the color coordinates are (0.16, 0.18). It is currently the most efficient blue light polymer. CN 101255336 B discloses a blue electroluminescent polymer in which the 3,7-position or 2,8-position of the S,S-dioxo-dibenzothiophene unit is linked to the main chain. CN 101712674 B discloses polymers of S,S-dioxo-dibenzothiophene units substituted by alkyl groups at the 2- and/or 8-position or at the 3- and/or 7-position. However, in the prior art, there is no explicit disclosure of the polymer claimed in the present invention.

Summary of the invention

In order to overcome the above-mentioned shortcomings in the prior art, the purpose of the present invention is to provide a type of electroluminescent polymer and its preparation method and application.

The primary purpose of the present invention is to provide a class of electroluminescent polymers for the current organic/polymer light emitting diodes (O/PLED). The electroluminescent polymer has better solubility and better photoelectric properties, is suitable for solution processing and inkjet printing, and has huge application potential.

Another object of the present invention is to provide a method for preparing the electroluminescent polymer.

Another object of the present invention is to provide the type of electroluminescent polymer that can be used in light-emitting diodes, organic field effect transistors, organic solar cells, organic laser diodes, etc., and is preferably used to prepare the light-emitting layer of light-emitting diode devices.

The purpose of the present invention is achieved by at least one of the following technical solutions.

The present invention provides a method for preparing a type of electroluminescent polymer, which comprises: under the protection of an inert gas, a solvent is used to completely dissolve the polymerized monomer unit of the electroluminescent polymer and the monomer containing the Ar structure, and Under the action of the catalyst and the action of tetraethylammonium hydroxide, the Suzuki polymerization reaction is carried out by heating; phenylboronic acid is added for constant temperature reaction; then bromobenzene is added to continue constant temperature reaction; the obtained reaction solution is purified to obtain the target product. The type of electroluminescent polymer provided by the present invention contains heteroatoms, which can improve the fluorescence quantum yield and carrier transport capacity of the luminescent material, and is beneficial for the luminescent device to obtain efficient and stable performance of the luminescent device. The type of electroluminescent polymer provided by the present invention has good solubility and can be dissolved in common organic solvents, and then the light-emitting layer of the light-emitting diode can be prepared by spin coating, ink-jet printing or film formation.

The polymerized monomer M1 or M2 of a type of electroluminescent polymer provided by the present invention is a derivative of S,S-dioxo-dibenzothiophene, which has high fluorescence quantum yield and excellent thermal stability, Electrochemical stability; polymerized monomer M1 or M2 has good planarity and strong rigidity, which is conducive to the transport of carriers, so that the light-emitting device can obtain high-efficiency and stable device performance; the electroluminescent polymer provided by the present invention has good solubility Performance, suitable for solution processing, can reduce the cost of device preparation, and can prepare large-area flexible OLED devices. Therefore, the type of electroluminescent polymer provided by the present invention has huge development potential and prospects in the field of organic electronic display.

The polymerized monomer of a type of electroluminescent polymer provided by the present invention has the chemical structural formula:

or

The chemical equation involved in the preparation method of the polymerized monomer of the electroluminescent polymer according to the present invention is as follows:

The preparation method of the polymerized monomer of the electroluminescent polymer according to the present invention includes the following steps:

(1) Under an inert gas environment, 1,4-dibromonaphthalene and phenyl borate or naphthalene borate are dissolved in tetrahydrofuran solution, acting as a catalyst for palladium tetrakistriphenylphosphine and an aqueous solution of alkali potassium carbonate or sodium carbonate Under the environment, heat to 70～90℃ and react for 12～24 hours. After stopping the suzuki coupling reaction, spin off the solvent, and purify by silica gel column chromatography with a mixed solvent of petroleum ether and dichloromethane (volume ratio 8:1) to obtain the compound 1-bromo-4-phenylnaphthalene or 4-bromo -1,1'-dibinaphthalene; wherein the molar ratio of 1,4-dibromonaphthalene, phenyl borate or naphthalene borate, catalyst, and base is 1-2:1:0.02-0.05:5-10, The mass concentration of the aqueous alkali solution is 40-80wt%, preferably 50wt%;

(2) Dissolve the compound 1-bromo-4-phenylnaphthalene or 4-bromo-1,1'-dinaphthalene in anhydrous tetrachloromethane, add liquid bromine and react for 6-24 hours under the condition of avoiding light at room temperature The bromination reaction was carried out. After the reaction stopped, the excess liquid bromine was removed with saturated NaHSO ₃ aqueous solution, extracted with dichloromethane three times, and the organic phase was concentrated and purified by silica gel column chromatography. Petroleum ether was used as the eluent to obtain 1-bromo- 4-(4-Bromophenyl)naphthalene or 4,4'-dibromo-1,1'-dibinaphthalene; the molar ratio of 1-bromo-4-phenylnaphthalene to liquid bromine is 1:1～1.5 Or the molar ratio of 4-bromo-1,1'-dinaphthalene to liquid bromine is 1:1～1.5;

(3) Dissolve the compound 1-bromo-4-(4-bromophenyl); naphthalene or 4,4'-dibromo-1,1'-binaphthalene in chloroform, and add chlorosulfonic acid dropwise, The temperature is stable at 20-50 degrees Celsius, and the reaction is 4-8 hours. After the reaction, the reactants were poured into a mixture of ice and water and adjusted to neutral with NaHCO ₃ solution. The insoluble matter was filtered out, washed with water several times and dried, and then recrystallized with acetic acid to obtain a white needle-like solid 5,9- Dibromobenzo[b]naphtho[1,2-d]thiophene-7,7-dioxide (M1) or 5,9-dibromonaphtho[2,1-b:1'2'-d ] Thiophene-7,7-dioxide (M2). Wherein, the molar ratio of 1-bromo-4-(4-bromophenyl)naphthalene or 4,4'-dibromo-1,1'-dipinnaphthalene to chlorosulfonic acid is 1:2-5.

A class of electroluminescent polymers provided by the present invention has the structural formula

or

Among them, 0≤x≤1; n is the degree of polymerization, and the value of n is 1-1000;

The structural unit Ar is one of the following conjugated or non-conjugated structural units:

Wherein, R ₁ is H, aryl, triphenylamine, linear alkyl with 1-20 carbon atoms, branched alkyl with 1-20 carbon atoms or alkoxy with 1-20 carbon atoms ; Z ₁ and Z ₂ are independently represented as hydrogen, deuterium, fluorine, alkenyl, alkynyl, nitrile, amine, nitro, acyl, alkoxy, carbonyl, sulfone, and carbon atoms of 1-30 An alkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aromatic hydrocarbon group having 6 to 60 carbon atoms, or an aromatic heterocyclic group having 3 to 60 carbon atoms.

The present invention provides a method for preparing the electroluminescent polymer, which includes the following steps:

(1) Under the protection of inert gas, add the polymerized monomer unit M1 and the monomer containing Ar structure or the polymerized monomer unit M2 and the monomer containing Ar structure into the organic solvent (the organic solvent needs to completely dissolve the polymerization The monomer unit M1 and the monomer containing the Ar structure or the polymerized monomer unit M2 and the monomer containing the Ar structure) are mixed uniformly, and then the catalyst function and the tetraethylammonium hydroxide aqueous solution (mass fraction 20%) are added. Mix evenly to obtain a mixed solution;

(2) The mixed solution described in step (1) is heated under the action of a catalyst and tetraethylammonium hydroxide to carry out Suzuki polymerization reaction, the temperature of Suzuki polymerization reaction is 60-100°C, and the time of Suzuki polymerization reaction is 12-36h , Keep the temperature constant, add phenylboronic acid, carry out the first isothermal reaction (6-12h), and then add bromobenzene under the condition of the same temperature, carry out the second isothermal reaction (6-12h) to obtain the reaction liquid, The reaction solution is purified to obtain the target product, that is, the electroluminescent polymer.

Further, the inert gas in step (1) is argon; the organic solvent is at least one of toluene, tetrahydrofuran, xylene, dioxane and N,N-dimethylformamide; the catalyst Is at least one of palladium acetate, tris(dibenzylideneacetone)dipalladium, tricyclohexylphosphorus, tetrakistriphenylphosphine palladium, and triphenylphosphine palladium dichloride; the molar amount of the catalyst is the reaction unit 5‰ to 3% of the total body mole; the volume ratio of the tetraethylammonium hydroxide aqueous solution to the organic solvent is 1:4-12.

Further, the structural formula of the polymerized monomer unit M1 in step (1) is

Step (1) The structural formula of the polymerized monomer unit M2 is

Further, in step (1), the polymerized monomer unit M1 and the Ar structure-containing monomer are added to the organic solvent, then the molar ratio of the polymerized monomer unit M1 to the Ar structure-containing monomer is x:1 -x (0≤x≤1), the volume ratio of the total molar amount of the polymerized monomers (including M1 or M2 and monomers containing Ar structure) to the organic solvent is 1:12-24.

When the polymerized monomer unit M2 and the Ar structure-containing monomer are added to the organic solvent, the molar ratio of the polymerized monomer unit M2 to the Ar structure-containing monomer is x: 1-x (0≤x≤1), the The volume ratio of the total molar amount of polymerized monomers (including M1 or M2 and monomers containing Ar structure) to the organic solvent is 1:12-24.

Further, in step (1), the amount of the polymerized monomer M1 or M2 and the monomer containing the Ar structure meets the requirements of the total molar amount of the monomer containing the bis-boronic acid ester (boric acid) functional group and the monomer containing the bis-bromine (iodine) functional group. The total moles of the body are equal (that is, the number of functional groups is the same).

Further, the amount of the catalyst used is 5‰ to 3% of the total molar amount of reacted monomers.

Further, the temperature of the Suzuki polymerization reaction in step (2) is 60-100°C, the time of the Suzuki polymerization reaction is 12-36h, and the time of the first constant temperature reaction is 6-12h; the second constant temperature The reaction time is 6-12h.

Further, the molar amount of phenylboronic acid in step (2) is 10-20% of the total molar amount of reacted monomers in step (1), and the molar amount of bromobenzene is 1% of the molar amount of phenylboronic acid. ~ 5 times. The total molar amount of the reactive monomer is the total molar amount of the polymerized monomer unit M1 and the monomer containing the Ar structure or the total molar amount of the polymerized monomer unit M2 and the monomer containing the Ar structure.

Further, the purification in step (2) includes: cooling the reaction solution to room temperature, pour it into methanol to precipitate, filter, and dry to obtain a crude product, and extract the crude product with methanol, acetone and n-hexane successively. It is dissolved in toluene, separated by column chromatography, concentrated and then precipitated in methanol solution again, filtered and dried to obtain the target product, that is, the electroluminescent polymer.

The type of electroluminescent polymer provided by the present invention can be used in the preparation of light-emitting layers of light-emitting diode devices.

The type of electroluminescent polymer provided by the present invention can be used in the process of preparing light-emitting diodes, organic field effect transistors, organic solar cells, organic laser diodes, etc., and is preferably used for preparing light-emitting layers of light-emitting diode devices.

In the process of preparing the light-emitting layer of a light-emitting diode device, the type of electroluminescent polymer provided by the present invention can be first dissolved in an organic solvent, and then spin-coated or inkjet Printing or printing into a film to obtain the light-emitting layer of the light-emitting diode device. In this process, the organic solvent is at least one of chlorobenzene, dichlorobenzene, toluene, xylene, tetrahydrofuran and chloroform. The thickness of the light-emitting layer of the light-emitting diode device is 10-1000 nm.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

(1) A type of electroluminescent polymer provided by the present invention, which contains heteroatoms, can increase the fluorescence quantum yield of the luminescent material, and improve the hole transport ability of the material. If used in the preparation of a light-emitting device, it is beneficial to make the light-emitting device Obtain efficient and stable performance;

(2) In the preparation method of a type of electroluminescent polymer provided by the present invention, the raw materials used are cheap, the synthetic route is simple, and the purification is convenient, which is suitable for large-scale production;

(3) A type of electroluminescent polymer provided by the present invention has good solubility properties, is suitable for solution processing, can reduce the cost of device preparation, and can prepare large-area flexible OLED devices; it has excellent electroluminescence properties, It has practical application potential; and when it is applied to the preparation of electroluminescent devices, annealing treatment is not required, and the preparation process of electroluminescent devices is simpler.

Description of the drawings

Figure 1 is a differential scanning calorimetry curve of polymers P1, P2, P4 and P7;

Figure 2 shows the fluorescence spectra of polymers P1～P3 and P7 in toluene solution;

Figure 3 shows the fluorescence spectra of polymers P8 and P9 in toluene solution;

Figure 4 shows the fluorescence spectra of polymers P10 and P11 in toluene solution.

Detailed ways

The specific implementation of the present invention will be further described below with reference to the drawings and examples, but the implementation and protection of the present invention are not limited to this. It should be pointed out that if there are processes that are not specifically described in detail below, those skilled in the art can implement or understand with reference to the prior art. If the manufacturer of the reagent or instrument is not indicated, it is regarded as a conventional product that can be purchased commercially.

The polymerized monomers (polymerized monomer unit M1 and polymerized monomer unit M2) used in the following examples can be prepared by the following method.

1. Preparation of polymerized monomer

Preparation of 1-bromo-4-phenylnaphthalene

Under argon atmosphere, add 1,4-dibromonaphthalene (9.68g, 34.1mmol), phenylborate (4.63g, 22.3mmol), and the catalyst tetrakistriphenylphosphine palladium (0.52g) into a 500mL three-necked flask under argon atmosphere. , 0.45mmol) and 180mL of tetrahydrofuran, stirring and heating, when the temperature stabilizes at 80°C, adding 24.6mL of 50wt% K ₂ CO ₃ (24.6g, 0.18mol) aqueous solution, and reacting for 12h. After concentrating the reaction solution, it was purified by silica gel column chromatography, using a mixed solvent of petroleum ether and dichloromethane (8/1, v/v) as the eluent to obtain a pale yellow solid with a yield of 72%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and the chemical reaction equation of the preparation process is as follows:

Preparation of 1-bromo-4-(4-bromophenyl)naphthalene

The compound 1-bromo-4-phenylnaphthalene (3.21 g, 11.4 mmol) was dissolved in 50 ml of anhydrous tetrachloromethane, and liquid bromine (2.19 g, 13.7 mmol) was added at room temperature and protected from light, and reacted for 12 hours. After the reaction was stopped, the excess liquid bromine was removed with saturated aqueous NaHSO ₃ solution, extracted with dichloromethane three times, the organic phase was concentrated, and purified by silica gel column chromatography with petroleum ether as the eluent to obtain 1-bromo-4-(4- Bromophenyl) naphthalene, the yield is 84%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and the chemical reaction equation of the preparation process is as follows:

Preparation of 5,9-dibromobenzo[b]naphtho[1,2-d]thiophene-7,7-dioxide (M1)

The compound 1-bromo-4-(4-bromophenyl)naphthalene (3.51g, 9.76mmol) was dissolved in 50ml of chloroform, and chlorosulfonic acid (3.40g, 29.3mmol) was added dropwise. The temperature was stable at 35 degrees Celsius. React for 6 hours. After the reaction, the reaction system was poured into a mixture of ice and water, and adjusted to neutral with NaHCO ₃ solution, the insoluble matter was filtered out, washed with water several times, dried, and then recrystallized with acetic acid to obtain a white needle-like solid 5,9- Dibromobenzo[b]naphtho[1,2-d]thiophene-7,7-dioxide (M1) is the polymerized monomer unit M1. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and the chemical reaction equation of the preparation process is as follows:

Preparation of 4-bromo-1,1'-dibinaphthalene

Under argon atmosphere, add 1,4-dibromonaphthalene (9.68g, 34.1mmol), naphthalene borate (5.67g, 22.3mmol), catalyst tetrakistriphenylphosphine palladium (0.52g) into a 500mL three-necked flask under argon atmosphere , 0.45mmol) and 180mL of tetrahydrofuran, stirring and heating, when the temperature stabilizes at 80°C, adding 24.6mL of 50wt% K ₂ CO ₃ (24.6g, 0.18mol) aqueous solution, and reacting for 12h. After concentrating the reaction solution, it was purified by silica gel column chromatography, using a mixed solvent of petroleum ether and dichloromethane (8/1, v/v) as the eluent to obtain a pale yellow solid with a yield of 72%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and the chemical reaction equation of the preparation process is as follows:

Preparation of 4,4'-dibromo-1,1'-dibinaphthalene

The compound 4-bromo-1,1'-dinaphthalene (4.02g, 12.1mmol) was dissolved in 50ml of anhydrous tetrachloromethane, and liquid bromine (2.32g, 14.5mmol) was added at room temperature and protected from light. Reaction 12. hour. After the reaction was stopped, the excess liquid bromine was removed with saturated aqueous NaHSO ₃ solution, extracted with dichloromethane three times, the organic phase was concentrated, and purified by silica gel column chromatography with petroleum ether as the eluent to obtain 1-bromo-4-(4- Bromophenyl) naphthalene, the yield is 71%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and the chemical reaction equation of the preparation process is as follows:

Preparation of 5,9-dibromonaphtho[2,1-b:1’2’-d]thiophene-7,7-dioxide (M2)

The compound 4,4'-dibromo-1,1'-dibinaphthalene (3.66g, 8.94mmol) was dissolved in ml of chloroform, chlorosulfonic acid (3.11g, 26.8mmol) was added dropwise, the temperature was stable 35 The reaction temperature is 6 hours. After the reaction, the reaction system was poured into a mixture of ice and water, and adjusted to neutral with NaHCO ₃ solution, the insoluble matter was filtered out, washed with water several times, dried, and then recrystallized with acetic acid to obtain a white needle-like solid 5,9- Dibromonaphtho[2,1-b:1'2'-d]thiophene-7,7-dioxide (M2), that is, the polymerized monomer unit M2. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and the chemical reaction equation of the preparation process is as follows:

2. Synthesis of electroluminescent polymer

Example 1 Synthesis of polymer P1

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (263.3mg, 0.48mmol) and the polymerized monomer unit M1 (8.4mg, 0.02mmol) were added to a 50ml two-necked flask, and then Add 12ml of refined toluene (toluene treated with concentrated sulfuric acid), then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), and then add 3ml of tetraethylammonium hydroxide aqueous solution (quality 20%), warm up to 80°C, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction and wait for the temperature After cooling down to room temperature, the product was added dropwise to 300ml methanol for precipitation, filtered, and then the crude product was dissolved in 20ml of toluene. 200-300 mesh silica gel was used as the stationary phase and toluene was used as the eluent for column chromatography. Concentrate, precipitate again in methanol, stir, filter, and vacuum dry to obtain a polymer solid; finally, extract with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; drop the concentrated tetrahydrofuran solution into methanol The fibrous solid electroluminescent polymer P1 (the electroluminescent polymer) obtained after precipitation and vacuum drying. ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P1, GPC (tetrahydrofuran): Mn=62000g/mol, Mw=38000g/mol, PDI=1.63; the chemical reaction equation of the preparation process is as follows:

The differential scanning calorimetry (DSC) curve of polymer P1 (the electroluminescent polymer) is shown in FIG. 1. It can be seen from the figure that during the entire heating process of the polymer P1, only the glass transition process occurred, and the glass transition temperature was 89°C, and no melting and crystallization process occurred. Compared with homopolymer P7 without monomer M1, the glass transition temperature is significantly increased, indicating that the polymer P1 has strong heat resistance and can meet the practical needs of polymers.

The fluorescence spectrum of the polymer P1 in the toluene solution is shown in Fig. 2. It can be seen from Fig. 2 that the maximum emission peak of the polymer P1 in the toluene solution is located at 416 nm, which is attributed to the emission of the conjugated main chain of the polymer P1. Polymer P1 has a shoulder peak at 436nm, which is due to the intramolecular charge transfer between the polyfluorene backbone and monomer M1. The fluorescence emission region of the polymer P1 in the toluene solution is located in the blue region.

Implementation case 2 Synthesis of polymer P2

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (246.8mg, 0.45mmol) and the polymerized monomer unit M1 (21.1mg, 0.05mmol) were added to a 50ml two-necked flask, and then Add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), and heat to 80 ℃, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, when the temperature drops to room temperature, add the product dropwise Precipitate in 300ml methanol, filter, and then dissolve the crude product in 20mL of toluene, use 200-300 mesh silica gel as the stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, and precipitate again in methanol After stirring, filtering, and vacuum drying, the polymer solid is obtained; finally, it is extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution is dropped into methanol for precipitation and vacuum dried. Fibrous solid electroluminescent polymer P2 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P2, GPC (tetrahydrofuran): Mn=73000g/mol, Mw=40,000g/mol, PDI=1.83; the chemical reaction equation of the preparation process is as follows:

The differential scanning calorimetry (DSC) curve of polymer P2 (the electroluminescent polymer) is shown in FIG. 1. It can be seen from the figure that during the entire heating process of the polymer P2, only the glass transition process occurred, and the glass transition temperature was 103° C., and no melting and crystallization process occurred. It shows that the polymer P2 has strong heat resistance and can meet the practical needs of polymers. Compared with polymer P1, during the synthesis process of polymer P2, the content of monomer M1 used increases, and the glass transition temperature increases. It shows that the polymerized monomer M1 is beneficial to the improvement of material stability.

The fluorescence spectrum of the polymer P2 in the toluene solution is shown in Figure 2. It can be seen from Figure 2 that the maximum emission peak of the polymer P2 in the toluene solution is located at 416 nm, which is attributed to the emission of the conjugated main chain of the polymer P2. Polymer P2 has a shoulder peak at 437nm, which is due to the intramolecular charge transfer between the polyfluorene main chain and monomer M1. As the content of monomer M1 increases, the shoulder peak intensity also increases. The fluorescence emission area is located in the blue area.

Example 3 Synthesis of polymer P3

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (219.4mg, 0.40mmol) and the polymerized monomer unit M1 (42.2mg, 0.10mmol) were added to a 50ml two-necked flask, and then Add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), and heat to 80 ℃, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, when the temperature drops to room temperature, add the product dropwise Precipitate in 300ml methanol, filter, and then dissolve the crude product in 20mL of toluene, use 200-300 mesh silica gel as the stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, and precipitate again in methanol After stirring, filtering, and vacuum drying, the polymer solid is obtained; finally, it is extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution is dropped into methanol for precipitation and vacuum dried. Fibrous solid electroluminescent polymer P3 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P3, GPC (tetrahydrofuran): Mn = 115000 g/mol, Mw = 71000 g/mol, PDI = 1.62; the chemical reaction equation of the preparation process is as follows:

The fluorescence spectrum of polymer P3 (the electroluminescent polymer) in toluene solution is shown in Figure 2. It can be seen from Figure 2 that the maximum emission peak of polymer P3 in toluene solution is located at 418 nm, which is attributed to polymer P3. Launch of the yoke main chain. Polymer P2 has a shoulder peak at 437nm. This is due to the intramolecular charge transfer between the polyfluorene backbone and monomer M1. The content of monomer M1 increases to 10%, and the charge transfer between the polyfluorene backbone and monomer M1 The effect is further enhanced. Compared with the polymers P1 and P2, the fluorescence spectrum of the polymer P3 is red-shifted, the half-peak width increases, and the phenomenon of broadening appears. The fluorescence emission of polymer P3 in the film state is in the blue region.

Example 4 Synthesis of polymer P4

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (263.3mg, 0.48mmol) and the polymerized monomer unit M2 (9.4mg, 0.02mmol) were added to a 50ml two-necked flask, and then Add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), and heat to 80 ℃, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, when the temperature drops to room temperature, add the product dropwise Precipitate in 300ml methanol, filter, and then dissolve the crude product in 20mL of toluene, use 200-300 mesh silica gel as the stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, and precipitate again in methanol After stirring, filtering, and vacuum drying, the polymer solid is obtained; finally, it is extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution is dropped into methanol for precipitation and vacuum dried. Fibrous solid electroluminescent polymer P4 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P4, GPC (tetrahydrofuran): Mn=87400g/mol, Mw=45000g/mol, PDI=1.94; the chemical reaction equation of the preparation process is as follows:

The differential scanning calorimetry (DSC) curve of polymer P4 (the electroluminescent polymer) is shown in FIG. 1. It can be seen from the figure that during the entire heating process of polymer P4, only the glass transition process occurs, and the glass transition temperature is 109°C, and there is no melting and crystallization process. Compared with homopolymer P7 without monomer M1, glass The significant increase in the transformation temperature indicates that the polymer P4 has strong heat resistance and can meet the practical needs of the polymer. And compared with polymer P1 (the monomer content is the same), the glass transition temperature is also increased, indicating that the rigidity of polymerized monomer M2 is stronger than that of monomer M1;

Example 5 Synthesis of polymer P5

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (246.8mg, 0.45mmol) and the polymerized monomer unit M2 (23.6mg, 0.05mmol) were added to a 50ml two-necked flask, and then Add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), and heat to 80 ℃, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, when the temperature drops to room temperature, add the product dropwise Precipitate in 300ml methanol, filter, and then dissolve the crude product in 20mL of toluene, use 200-300 mesh silica gel as the stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, and precipitate again in methanol After stirring, filtering, and vacuum drying, the polymer solid is obtained; finally, it is extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution is dropped into methanol for precipitation and vacuum dried. Fibrous solid electroluminescent polymer P5 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P5, GPC (tetrahydrofuran): Mn=97000g/mol, Mw=54000g/mol, PDI=1.80; the chemical reaction equation of the preparation process is as follows:

The effect of polymer P5 is similar to that of polymer P4, and it has strong heat resistance, which can meet the practical needs of polymer, as shown in Figure 1.

Example 6 Synthesis of polymer P6

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (219.4mg, 0.40mmol) and the polymerized monomer unit M1 (47.2mg, 0.10mmol) were added to a 50ml two-necked flask, and then Add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), and heat to 80 ℃, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, when the temperature drops to room temperature, add the product dropwise Precipitate in 300ml methanol, filter, and then dissolve the crude product in 20mL of toluene, use 200-300 mesh silica gel as the stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, and precipitate again in methanol After stirring, filtering, and vacuum drying, the polymer solid is obtained; finally, it is extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution is dropped into methanol for precipitation and vacuum dried. Fibrous solid electroluminescent polymer P6 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P6, GPC (tetrahydrofuran): Mn=156000g/mol, Mw=83000g/mol, PDI=1.88; the chemical reaction equation of the preparation process is as follows:

The effect of polymer P6 is similar to that of polymer P1. It has strong heat resistance and can meet the practical needs of polymers. Refer to Figure 1.

Example 7 Synthesis of polymer P7

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (274.2mg, 0.50mmol) into a 50ml two-necked flask, then add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol ) And tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction of 20%), warm up to 80℃, react for 24 hours; then add 24.3mg of phenylboronic acid for capping After 12 hours, capped with 0.1ml bromobenzene; after continuing the reaction for 12 hours, stop the reaction. After the temperature drops to room temperature, add the product dropwise to 300ml methanol for precipitation, filter, and then dissolve the crude product in 20mL In the toluene, 200-300 mesh silica gel is used as the stationary phase, and toluene is used as the eluent for column chromatography, the solvent is concentrated, and it is precipitated in methanol again, stirred, filtered, and vacuum dried to obtain a polymer solid; Extraction with methanol, acetone and tetrahydrofuran for 24 hours in turn to remove small molecules; drop the concentrated tetrahydrofuran solution into methanol for precipitation, and vacuum dry the resulting fibrous solid electroluminescent polymer P7 (the electroluminescent polymer) polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P7, GPC (tetrahydrofuran): Mn=68000g/mol, Mw=35000g/mol, PDI=1.94; the chemical reaction equation of the preparation process is as follows:

The effect of polymer P7 is similar to that of polymer P1, and it has strong heat resistance, which can meet the practical needs of polymers. Refer to Figure 1. The differential scanning calorimetry (DSC) curve of polymer P7 (the electroluminescent polymer) is shown in FIG. 1. It can be seen from the figure that homopolymer P7 has a glass transition at 71°C and a liquid crystal transition at 160°C during the entire heating process. Compared with polymers P1 and P2 containing monomer M1 and P4 containing monomer M2 (the monomer content is the same), the glass transition temperature of polymer P7 is significantly lower, indicating the introduction of monomers M1 and M2 Conducive to improving the thermal stability of the polymer;

The fluorescence spectrum of polymer P7 (the electroluminescent polymer) in toluene solution is shown in Figure 2. It can be seen from Figure 2 that the maximum emission peak of polymer P7 in toluene solution is located at 416nm, and the shoulder peak is located at 439nm. The characteristic peak of polyfluorene. The fluorescence emission area is located in the blue area.

Example 8 Synthesis of polymer P8

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-N-9'-heptadecyl Carbazole (335mg, 0.50mmol), 2,7-dibromo-N-9'-heptadecylcarbazole (254mg, 0.45mmol) and polymerized monomer unit M1 (21.1mg, 0.05mmol) were added to a 50ml two-necked flask Inside, add 12ml refined toluene, add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), Warm up to 80°C and react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, wait until the temperature drops to room temperature, the product Add dropwise to 300ml methanol for precipitation, filter, and then dissolve the crude product in 20ml of toluene, use 200-300 mesh silica gel as a stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, and again in methanol After precipitation, stirring, filtering, and vacuum drying, the polymer solid is obtained; finally, it is extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution is dropped into methanol for precipitation and vacuum drying The fibrous solid electroluminescent polymer P8 (the electroluminescent polymer) obtained later. ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P8, GPC (tetrahydrofuran): Mn=82000g/mol, Mw=40800g/mol, PDI=2.01; the chemical reaction equation of the preparation process is as follows:

The fluorescence spectrum of polymer P8 (the electroluminescent polymer) in toluene solution is shown in Figure 3. It can be seen from Figure 3 that the maximum emission peak of polymer P8 in toluene solution is located at 419nm, and the shoulder peak is located at 443nm. The fluorescence emission area is located in the blue area.

Compared with polymer P1, the content of monomer M1 is the same as 5%, but the fluorescence spectrum of polymer P8 is obviously red-shifted. This is because the electron donating ability of carbazole is stronger than that of fluorene, which makes the charge transfer function in the molecular chain. P8 is stronger than that caused by polymer P1.

The effect of polymer P8 is similar to that of polymer P1, and it has strong heat resistance, which can meet the practical needs of polymer, as shown in Figure 1.

Example 9 Synthesis of polymer P9

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-N-9'-heptadecyl Carbazole (335mg, 0.50mmol), 2,7-dibromo-N-9'-heptadecylcarbazole (225.4mg, 0.40mmol) and the polymerized monomer unit M2 (23.6mg, 0.05mmol) were added In a 50ml two-necked flask, add 12ml of refined toluene, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), and then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction of 20 %), warm up to 80°C, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.1ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction and wait until the temperature drops to room temperature The product was added dropwise to 300ml methanol for precipitation, filtered, and then the crude product was dissolved in 20mL of toluene, 200-300 mesh silica gel was used as the stationary phase, and toluene was used as the eluent for column chromatography, the solvent was concentrated, and again Precipitate in methanol, stir, filter, and vacuum dry to obtain a polymer solid; finally, extract with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; drop the concentrated tetrahydrofuran solution into methanol for precipitation , The fibrous solid electroluminescent polymer P9 (the electroluminescent polymer) obtained after vacuum drying. ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P9, GPC (tetrahydrofuran): Mn=79300g/mol, Mw=40600g/mol, PDI=1.95; the chemical reaction equation of the preparation process is as follows:

The fluorescence spectrum of polymer P9 (the electroluminescent polymer) in toluene solution is shown in Fig. 3. As can be seen from Fig. 3, the maximum emission peak of polymer P9 in toluene solution is located at 420 nm, and the shoulder peak is located at 444 nm. The fluorescence emission area is located in the blue area.

Compared with polymer P8, the content of polymerized monomers M1 and M2 is the same at 5%, but the fluorescence spectrum of polymer P8 is slightly red shifted. This is because the electron donating ability of monomer M2 is stronger than that of monomer M1, which makes the molecule Intra-chain charge transfer is caused by polymer P9 stronger than polymer P8.

The effect of polymer P9 is similar to that of polymer P4, and it has strong heat resistance, which can meet the practical needs of polymer, as shown in Figure 1.

Example 10 Synthesis of polymer P10

(1) 4,7-Dibromo-2,1,3-benzothiadiazole

Under dark conditions, add 2,1,3-benzothiadiazole (5.0g, 36.8mmol) and hydrobromic acid aqueous solution (100mL, 47wt%) into a 250mL three-necked flask, heat to reflux, and then use constant pressure A mixture of hydrobromic acid solution and liquid bromine solution (4.8 mL, 92 mmol) was added dropwise to the dropping funnel. After 6 hours, NaHSO ₃ aqueous solution was added and stirred until colorless to remove excess liquid bromine, and then filtered with Buchner funnel, the filter cake was washed with deionized water and ethanol for several times. The solid was purified with 100-200 mesh silica gel column, petroleum ether and dichloromethane 1/1 (volume ratio) as the eluent, and then further purified with chloroform solution to obtain 11.8g yellow needle-like crystals, yield: 80 %. ^{The results of 1} H NMR, ¹³ C NMR, MS and elemental analysis show that the obtained compound is the target product. The chemical reaction equation of the preparation process is as follows:

(2) Preparation of polymer P10

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (191.9mg, 0.35mmol), the polymerized monomer unit M2 (23.6mg, 0.05mmol) and 4,7-dibromo -2,1,3-benzothiadiazole (2.9mg, 0.01mmol) was added to a 50mL two-necked flask, then 8mL of toluene was added for complete dissolution, and then palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine ( 6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction of 20%), warm up to 80℃, react for 24 hours; then add 24.3mg of phenylboronic acid for end-capping, 12 hours later, use 0.1ml of bromobenzene was blocked; after the reaction continued for 12 hours, the reaction was stopped. After the temperature dropped to room temperature, the product was dropped into 300mL methanol for precipitation, filtered, and then the crude product was dissolved in 20mL of toluene to 300 mesh silica gel was used as the stationary phase, and toluene was used as the eluent for column chromatography. The solvent was concentrated, precipitated in methanol again, stirred, filtered, and dried in vacuo to obtain a polymer solid; finally, methanol, acetone, and tetrahydrofuran were used in sequence. Extraction for 24 hours each to remove small molecules; drop the concentrated tetrahydrofuran solution into methanol for precipitation, and vacuum dry the resulting fibrous solid conjugated polymer P10 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P10, GPC (tetrahydrofuran): Mn=79300g/mol, Mw=40600g/mol, PDI=1.95; the chemical reaction equation of the preparation process is as follows:

The fluorescence spectrum of polymer P10 (the electroluminescent polymer) in toluene solution is shown in Figure 4. It can be seen from the figure that the position of the strongest fluorescence emission peak of polymer P10 is at 441 nm, and the shoulder peak is at 522 nm. , Belongs to the green light emitting area. The emission peak at 441nm is the emission of the poly(9.9-dioctylfluorene-co-naphtho[2,1-b:1'2'-d]thiophene-7,7-dioxide) conjugated backbone The emission peak at 522nm is the intramolecular electron-donating unit 9,9-dioctylfluorene, the electron-donating unit 2,1,3-benzothiadiazole and the electron-withdrawing unit naphtho[2,1-b:1' 2'-d] thiophene-7,7-dioxide in the charge transfer state generated by intramolecular interaction. Poly(9.9-dioctylfluorene-co-naphtho[2,1-b:1'2'-d]thiophene-7,7-dioxide) host and guest 2,1,3-benzothiadi Energy transfer occurs between the units, but the energy transfer is incomplete.

The effect of polymer P10 is similar to that of polymer P4, and it has strong heat resistance, which can meet the practical needs of polymer, as shown in Figure 1.

Example 11 Preparation of polymer P11

(1) 4,7-bis(4-hexylthiophen-2-yl)-2,1,3-benzothiadiazole

Tributyl-(4-hexylthiophen-2-yl)stannane (15.0g, 33.1mmol), 4,7-dibromo-2,1,3-benzothiadiazole (4.4g, 15.0mmol) at room temperature Dissolve in 100mL refined THF solvent. Under a nitrogen atmosphere, the catalyst PdCl ₂ (PPh ₃ ) ₂ (221 mg, 0.15 mmol) was added, stirred and heated to reflux, and reacted for 12 hours. After the reaction was stopped, the solvent was spinned to dryness, and the mixture was used on a 100-200 mesh silica gel column with PE/DCM 5/1 (volume ratio) as the eluent to obtain 5.8 g of orange-red solid with a yield of 82%. ¹ H NMR, ¹³ C NMR, MS and elemental analysis results show that the obtained compound is the target product.

(2) 4,7-bis(5-bromo-(4-hexylthiophene)-2-yl)-2,1,3-benzothiadiazole

Add 4,7-bis(4-hexylthiophen-2-yl)-2,1,3-benzothiadiazole (4.68g, 10mmol) into the reaction flask, and then use 150mL THF solvent to completely dissolve the raw materials, and the NBS The powder (2.28g, 24mmol) was added to the reaction flask in three batches and reacted for 24 hours in the dark. The solvent was spin-dried, the crude product was separated and purified by column chromatography, PE/DCM was 3/1 (volume ratio) as eluent, and then recrystallized with n-hexane to obtain 4.86 g of red needle-like solid. The yield was 78%. ¹ H NMR, ¹³ C NMR, MS and elemental analysis results show that the obtained compound is the target product. The chemical reaction equation of the preparation process is as follows:

(3) Preparation of polymer P11

In an argon atmosphere, 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-diyl)-9,9-dioctylfluorene ( 321mg, 0.50mmol), 2,7-dibromo-9,9-dioctylfluorene (191.9mg, 0.35mmol), the polymerized monomer unit M2 (23.6mg, 0.05mmol) and 4,7-bis( 5-Bromo-(4-hexylthiophene)-2-yl)-2,1,3-benzothiadiazole (6.3mg, 0.01mmol) was added to a 50mL two-necked flask, and then 8mL of toluene was added for complete dissolution, and then added Palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), then add 3ml of tetraethylammonium hydroxide aqueous solution (mass fraction 20%), raise the temperature to 80℃, and react for 24 hours; Add 24.3mg of phenylboronic acid for end-capping, 12 hours later, then use 0.06 ml of bromobenzene for end-capping; after continuing the reaction for 12 hours, stop the reaction, wait until the temperature drops to room temperature, drop the product in 300mL methanol for precipitation, filter , And then dissolve the crude product in 20mL of toluene, use 200-300 mesh silica gel as the stationary phase, use toluene as the eluent for column chromatography, concentrate the solvent, precipitate it out in methanol again, stir, filter, and dry in vacuo Then the polymer solid was obtained; finally, it was extracted with methanol, acetone, and tetrahydrofuran for 24 hours to remove small molecules; the concentrated tetrahydrofuran solution was dropped into methanol for precipitation, and the fibrous solid conjugated polymer was obtained after vacuum drying P11 (the electroluminescent polymer). ¹ H NMR, GPC and elemental analysis results characterize the electroluminescent polymer P11, GPC (tetrahydrofuran): Mn=91400g/mol, Mw=52600g/mol, PDI=1.74; the chemical reaction equation of the preparation process is as follows:

The fluorescence spectrum of polymer P11 (the electroluminescent polymer) in a toluene solution is shown in Figure 4. From the figure, it can be seen that the position of the strongest fluorescence emission peak of polymer P11 (the electroluminescent polymer) At 441nm, 621nm is the shoulder peak, which belongs to the red light emitting region. The emission peak at 441nm is the emission of the poly(9.9-dioctylfluorene-co-naphtho[2,1-b:1'2'-d]thiophene-7,7-dioxide) conjugated backbone , The emission peak at 621nm is the intramolecular electron-donating unit 9,9-dioctyl fluorene, the electron-donating red light unit 4,7-bis(5-bromo-(4-hexylthiophene)-2-yl)-2, Intramolecular interaction between 1,3-benzothiadiazole and electron withdrawing unit naphtho[2,1-b:1'2'-d]thiophene-7,7-dioxide produces a charge transfer state emission. Poly(9.9-dioctylfluorene-co-naphtho[2,1-b:1'2'-d]thiophene-7,7-dioxide) host and guest 4,7-bis(5-bromo- Energy transfer occurs between (4-hexylthiophene)-2-yl)-2,1,3-benzothiadiazole units, but the energy transfer is incomplete.

The effect of the polymer P11 is similar to that of the polymer P4, and it has strong heat resistance, which can meet the practical needs of the polymer, as shown in Figure 1.

Implementation case 12

Preparation of organic electroluminescent devices

1) Cleaning of ITO conductive glass: Place the ITO glass substrate on the washing rack, and use an ultrasonic device for ultrasonic cleaning. The order of washing liquid is acetone, isopropanol, detergent, deionized water and isopropanol. The purpose is to fully remove the possible residual stains such as photoresist on the surface of the ITO glass substrate, and improve the interface contact, and then dry it in a vacuum oven;

2) Place the ITO in an oxygen plasma etching apparatus, and use O ₂ Plasma for 20 minutes of bombardment to completely remove the possible residual organic matter on the surface of the ITO glass substrate;

3) Spin-coating a 40nm thick hole injection layer PEDOT:PSS (Baytron P4083) on ITO, and then dry it in a vacuum oven at 80°C for 12 hours;

4) After spin-coating a layer of 80nm thick electroluminescent polymer film on the PEDOT:PSS layer in a glove box in a nitrogen atmosphere, it is heated and annealed on a heating stage at 80°C for 20 minutes to remove residual solvents and improve Morphology of the light-emitting layer;

5) A 1.5nm thick cesium fluoride (CsF) layer is deposited on the organic film in a vacuum evaporation chamber at a vacuum degree of less than 3×10 ^-4 Pa, which helps electron injection; A layer of 110nm thick aluminum cathode (Al) is vapor-deposited on the top, and the cesium fluoride and aluminum layers are vacuum deposited through a mask.

The effective area of the device is 0.16 cm ² . Measure the thickness of the organic layer with a quartz crystal monitoring thickness meter. After the device is prepared, epoxy resin and thin-layer glass are polarized and encapsulated in ultraviolet light to obtain a single-layer electroluminescent device. The structure of the single-layer electroluminescent device is (ITO/PEDOT:PSS/EMITTER (80nm)/CsF (1.5nm)/Al (110nm)).

The electroluminescent polymers described in step 4) of the above preparation method are the polymers prepared in Example 1 to Example 11, respectively. Photoelectric performance tests were performed on the obtained electroluminescent devices. The test results are shown in Table 1. Table 1 is a data table of electroluminescence performance of the electroluminescent devices prepared by using the polymers of various examples.

Table 1

It can be seen from Table 1 that the present invention uses electroluminescent polymers P1 to P11 (polymers prepared in Example 1 to Example 11) as the light-emitting layer to prepare a single-layer PLED device, and its structure is ITO/PEDOT:PSS/EMITTER/ CsF/Al. The maximum lumen efficiency obtained by the blue light device is 6.21 cd/A, the maximum brightness is 17615 cd/m ² , and the color coordinate is (0.16, 0.12). The excellent device performance shows that the material described in this patent has practical application potential. Among them, the maximum lumen efficiency of the green light device is 19.8cd/A, the maximum brightness is 21667cd/m ² , and the color coordinate is (0.37, 0.57); the maximum lumen efficiency of the red light device is 5.8cd/A, and the maximum brightness is 5292cd/m ^{2. The} color coordinate is (0.63, 0.36). Through subsequent device optimization, higher device performance can be obtained.

Compared with the poly[9,9-dioctylfluorene-co-3,7-S,S-dioxydibenzothiophene] (PFSOs) reported in the journal "Organic Electronics" (Organic Electronics, 2009, 10, 901-909) Compared with the polymer P1 to P6 provided by the present invention, the performance is more excellent. When the polymerized monomer content is the same as 10%, compare polymers PFSO10, P3 and P6, and use PFSO10 as the light-emitting layer to prepare a single-layer electroluminescent device. The maximum lumen efficiency is 3.28cd/A, and the maximum brightness is 4561cd/m ² . The lighting voltage is 4.4V. The maximum lumen efficiency of the single-layer device based on polymer P3 of the present invention is 4.83 cd/A, the maximum brightness is 14550 cd/m ² , and the lighting voltage is 3.0V; the maximum lumen efficiency of the single-layer device based on polymer P6 is 6.21 cd/A, the maximum brightness is 17615cd/m ² , and the lighting voltage is 3.0V. The performance parameters of polymer P6 containing monomer M2 are higher than those of polymer P3 containing monomer M1, and higher than the reported PFSO10. The above data shows that the polymer provided by the present invention has excellent electroluminescence properties and has practical application potential. In addition, the performance of the polymerized monomer M2 with a symmetric structure is better than that of the monomer M1.

The above examples are only preferred embodiments of the present invention, and are only used to explain the present invention, but not to limit the present invention. Changes, substitutions, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention shall belong to the present invention. The scope of protection of the invention.

Claims (10)

1. A type of electroluminescent polymer, characterized in that its structural formula is

   

   or

   

   Among them, 0≤x≤1; n is the degree of polymerization, and the value of n is 1-1000;

   The structural unit Ar is one of the following conjugated or non-conjugated structural units:

   

   

   Wherein, R ₁ is H, aryl, triphenylamine, linear alkyl with 1-20 carbon atoms, branched alkyl with 1-20 carbon atoms or alkoxy with 1-20 carbon atoms ; Z ₁ and Z ₂ are independently represented as hydrogen, deuterium, fluorine, alkenyl, alkynyl, nitrile, amine, nitro, acyl, alkoxy, carbonyl, sulfone, and carbon atoms of 1-30 An alkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aromatic hydrocarbon group having 6 to 60 carbon atoms, or an aromatic heterocyclic group having 3 to 60 carbon atoms.
2. A method for preparing the electroluminescent polymer according to claim 1, characterized in that it comprises the following steps:

   (1) Under the protection of inert gas, add the polymerized monomer unit M1 and the monomer containing Ar structure or the polymerized monomer unit M2 and the monomer containing Ar structure into the organic solvent, mix well, and then add the catalyst and Mix the tetraethylammonium hydroxide aqueous solution evenly to obtain a mixed solution;

   (2) Heat the mixed solution described in step (1) to perform Suzuki polymerization reaction, add phenylboronic acid while maintaining the temperature, perform the first constant temperature reaction, and then add bromobenzene with the temperature unchanged, perform the second A constant temperature reaction is performed to obtain a reaction solution, and the reaction solution is purified to obtain the electroluminescent polymer.
3. The method for preparing electroluminescent polymers according to claim 2, wherein the inert gas in step (1) is argon; the organic solvent is toluene, tetrahydrofuran, xylene, dioxane and N, At least one of N-dimethylformamide; the catalyst is palladium acetate, tris(dibenzylideneacetone)dipalladium, tricyclohexylphosphorus, tetrakistriphenylphosphine palladium and triphenylphosphine dichloride At least one of palladium; the molar amount of the catalyst is 5‰ to 3% of the total molar amount of the reaction monomer, and the total molar amount of the reaction monomer is both the polymerized monomer unit M1 and the monomer containing the Ar structure Or the total molar amount of the polymerized monomer unit M2 and the monomer containing the Ar structure; the volume ratio of the tetraethylammonium hydroxide aqueous solution to the organic solvent is 1:4-12.
4. The method for preparing an electroluminescent polymer according to claim 2, wherein the structural formula of the polymerized monomer unit M1 in step (1) is

   

   The structural formula of the polymerized monomer unit M2 in step (1) is

   
5. The method for preparing electroluminescent polymers according to claim 2, characterized in that, in step (1), when the polymerized monomer unit M1 and the monomer containing Ar structure are added to the organic solvent, the polymerized monomer The molar ratio of the body unit M1 to the monomer containing the Ar structure is x: 1-x (0≤x≤1), and the volume ratio of the total molar amount of the polymerized monomer to the organic solvent is 1:12-24, so The polymerized monomer includes polymerized monomer unit M1 and a monomer containing Ar structure;

   When the polymerized monomer unit M2 and the Ar structure-containing monomer are added to the organic solvent, the molar ratio of the polymerized monomer unit M2 and the Ar structure-containing monomer is x: 1-x (0≤x≤1), so The volume ratio of the total molar amount of the polymerized monomer to the organic solvent is 1:12-24; the polymerized monomer includes a polymerized monomer unit M2 and a monomer containing an Ar structure.
6. The method for preparing an electroluminescent polymer according to claim 2, wherein the temperature of the Suzuki polymerization reaction in step (2) is 60-100°C, the time of the Suzuki polymerization reaction is 12-36h, and the The time of the first constant temperature reaction is 6-12h; the time of the second constant temperature reaction is 6-12h.
7. The method for preparing an electroluminescent polymer according to claim 2, wherein the molar amount of the phenylboronic acid in step (2) is 10-20% of the total molar amount of the reactive monomer in step (1).
8. The method for preparing an electroluminescent polymer according to claim 2, wherein the molar amount of bromobenzene in step (2) is 1 to 5 times the molar amount of phenylboronic acid.
9. The method for preparing an electroluminescent polymer according to claim 2, wherein the purification in step (2) comprises: cooling the reaction solution to room temperature, pour it into methanol for precipitation, filtering, and drying to obtain a crude product , The crude product was extracted with methanol, acetone and n-hexane successively, then dissolved with toluene, separated by column chromatography, concentrated and then precipitated in methanol solution again, filtered and dried to obtain the electroluminescent polymer .
10. The use of a type of electroluminescent polymer according to claim 1 in the preparation of a light-emitting layer of a light-emitting diode device.

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