CN100432181C - Blue light-emitting electroluminescent polyfluorene material and its prepn process - Google Patents

Abstract

The invention relates to a blue electroluminescent polymer material and a preparation method thereof. The present invention is based on the physical idea that dark blue polymers can effectively transfer energy to blue or blue-green fluorescent dye molecules. Polyfluorene is used as the dark blue polymer matrix, and blue or blue-green naphthalene with high fluorescence quantum efficiency is used. The amine unit is a doping guest unit, and the doping guest unit is chemically grafted onto the dark blue polymer matrix to realize the molecular level dispersion of the doping guest unit in the dark blue polymer matrix. By adjusting the blue or blue-green fluorescent dye The relative content of the molecule in the dark blue polymer matrix can realize partial or complete energy transfer from the dark blue polymer to the blue or blue-green fluorescent dye molecules, enhance the luminescence of the blue or blue-green fluorescent dye molecules, and then realize the pure polymer material Blue electroluminescence, constructing a class of molecularly dispersed blue electroluminescent polymer materials.

Description

Blue electroluminescent polymer polyfluorene material and preparation method thereof

technical field

The invention relates to a blue electroluminescence polymer polyfluorene material and a preparation method thereof.

technical background

Since the Cavendish Laboratory of the University of Cambridge reported the electroluminescent diode of conjugated polymer for the first time in 1990, polymer electroluminescent materials and devices have outstanding characteristics such as simple process, low cost, and easy realization of large-screen display and flexible display. It has received extensive attention and competing investment from academia and industry. In order to realize the full-color display of polymer luminescence, it is necessary to develop electroluminescent polymer materials that can emit the three primary colors of red, green and blue. At present, red light and green light polymer materials have reached the requirements of practical application, while the indicators of blue light polymer materials, including efficiency and lifespan, are still far from practical application. One of the main bottlenecks in the industrialization of display screens.

Polyfluorene and its derivatives are typical blue light polymers with high fluorescence quantum efficiency, good light, heat and chemical stability, and are considered to be one of the most promising polymer blue light materials. In order to improve the electroluminescent efficiency of polyfluorene and its derivative devices, it is usually adopted to introduce carrier transport units into the main chain or terminal group of the polymer to adjust the carrier balance of the electroluminescent device to improve its electroluminescence. The purpose of luminous efficiency. For example: American DowChemical Co., Ltd. has obtained a blue-light polyfluorene polymer material with an electroluminescent efficiency of 2.82cd/A by copolymerizing triarylamine units with hole transport properties into the main chain of polyfluorene (Microelectronics Journal, 35, 343-348, 2004). After the German U.Scherf research group capped polyfluorene with triarylamine units, the obtained polymer luminescent material had an electroluminescent efficiency of up to 1.1cd/A (Advanced Materials 13, 565-570, 2001).

Contents of the invention

The object of the present invention is to provide a kind of molecular dispersion type blue electroluminescence polymer material.

Another object of the present invention is to provide a method for preparing a blue electroluminescence polymer material.

The present invention is based on the physical idea that dark blue polymers can effectively transfer energy to blue or blue-green fluorescent dye molecules. Polyfluorene is used as the dark blue polymer matrix, and blue or blue-green naphthalene with high fluorescence quantum efficiency is used. The amine unit is a doping guest unit, and the doping guest unit is chemically grafted onto the dark blue polymer matrix to realize the molecular level dispersion of the doping guest unit in the dark blue polymer matrix. By adjusting the blue or blue-green fluorescent dye The relative content of the molecule in the dark blue polymer matrix can realize partial or complete energy transfer from the dark blue polymer to the blue or blue-green fluorescent dye molecules, enhance the luminescence of the blue or blue-green fluorescent dye molecules, and then realize the pure polymer material Blue electroluminescence, constructing a class of molecularly dispersed blue electroluminescent polymer materials.

The molecularly dispersed blue electroluminescent polymer material provided by the present invention has the following structure:

Wherein: R ₁ is selected from hexyl, octyl, phenyl or 4-(diphenylamino) phenyl substituted by an alkyl group with 1-10 carbon atoms; R ₂ is selected from hydrogen or 1-10 carbon atoms Alkyl group of 10;

Ar is a naphthalimide derivative radical, selected from one or both of the following structural units:

Wherein, _R3 is selected from hydrogen or an alkyl group with 1-10 carbon atoms, _R4 is selected from hydrogen; X is selected from oxygen atom or sulfur atom; 1≤p≤5;

x is the content of naphthalimide units, satisfying 0<x≤1, m=1-20, n=1-300.

The preparation method of the blue electroluminescent polymer material provided by the invention is:

(1). Preparation of 2,7-dibromofluorene derivative monomer

The general structural formula of 2,7-dibromofluorene derivative monomer is:

Dissolve 2,7-dibromofluorene and excess bromoalkane in toluene, then add aqueous sodium hydroxide solution, react under nitrogen protection, pour the reaction product into water, separate the organic phase, wash with water several times, Drying, concentration, and recrystallization to obtain 9,9-dialkyl-2,7-dibromofluorene;

(2). Preparation of 2,7-bisboronate fluorene derivative monomer

The general structural formula of 2,7-bisboronate fluorene derivative monomer is:

2, the preparation method of 7-bisboronate fluorene derivative monomer is as follows:

Add n-butyllithium to the tetrahydrofuran solution of 9,9-dialkyl-2,7-dibromofluorene at -78-0°C, stir the reaction, and add excess triboric acid at -78-0°C Methyl ester, stirred at room temperature, poured the reaction mixture into water, separated the organic phase, washed several times with water, dried and concentrated, dissolved the obtained product in toluene, and then added 1,3-propanediol with a molar ratio of 2-3 times , refluxing, pouring the reaction product into water, separating the organic phase, washing with water several times, drying, concentrating, and recrystallizing from ethanol to obtain 2,7-bisboronate fluorene derivatives;

(3). Preparation of bisbromonaphthalimide derivative monomer

1) Bisbromofluorene mononaphthalimide derivative monomer

Wherein Ar is the naphthalimide derivative radical;

The preparation method of bisbromofluorene mononaphthalimide derivative monomer is as follows:

First, dissolve 9-alkyl-2,7-dibromofluorene and dibromoalkane with a molar ratio of 1-6 times the number of chain members m in toluene, and then add a molar ratio of 1-50 times The 9-alkyl-9- (m-bromoalkyl)-2,7-dibromofluorene; then, dissolve the naphthalimide derivative in DMSO, add potassium hydroxide with a molar ratio of 1-10 times, and then add a molar ratio of 1 -5 times of 9-alkyl-9-(m-bromoalkyl)-2,7-dibromofluorene, after reacting at a temperature of 20-150°C for 1-50 hours, terminate the reaction with water, and separate the organic phase, After repeated washing with water several times, drying, concentrating, and column separation, the bisbromofluorene mononaphthalimide derivative monomer is obtained;

2) Bisbromofluorene bisnaphthimide derivative monomer

Wherein Ar is the naphthalimide derivative radical;

The preparation method of bisbrominated fluorene bis-naphthalimide derivative monomer is as follows:

First, dissolve 2,7-dibromofluorene and dibromoalkane with a molar ratio of 2-6 times the number of chain members m in toluene, and then add 10-70% of the molar ratio of 2-100 times Sodium hydroxide aqueous solution and tetrabutylammonium bromide with a molar ratio of 0.005-0.2 are reacted at 30-100°C for 1-72 hours under the protection of nitrogen to prepare 9,9-(m-bromoalkyl)- 2,7-dibromofluorene; then, dissolve the naphthalimide derivative in DMSO, add sodium hydroxide with a molar ratio of 1-10 times, and then add 9,9- (m-bromoalkyl)-2,7-dibromofluorene, after reacting at 20-150°C for 1-50 hours, terminate the reaction with water, separate the organic phase, wash with water several times, dry, concentrate, and Separation to obtain bis-bromofluorene bis-naphthalimide derivative monomer;

(4) Preparation of blue electroluminescent polymer materials

The preparation of the blue electroluminescence polymer material adopts Suzuki polymerization reaction, and its preparation method is as follows:

2,7-bis-boronate fluorene derivative monomer, 0.001%-100% molar ratio of bisbromonaphthalimide derivative monomer, 0-100% molar ratio of 2,7-bisbromofluorene The derivative monomer is dissolved in toluene, and then 2.0M aqueous potassium carbonate solution with a molar ratio of 2-10 times is added; under nitrogen protection and a temperature of 50-100°C, 0.05%-10% molar ratio of tetrakis(triphenyl Phosphine) palladium, 0-50% molar ratio of Aliquat 336; after reacting for 24-120 hours, extracting with chloroform, washing with water, drying, concentrating, settling with methanol, extracting with solvent, and drying in vacuum to obtain fibrous polymer material.

Instructions attached

Figure 1 is the solid-state absorption spectrum and fluorescence emission spectrum of the blue electroluminescent polymer.

Fig. 2 is the electroluminescence spectrum of a single-layer device based on blue electroluminescent polymer with a structure of ITO/PEDOT/blue electroluminescent polymer/Ca/Al.

As can be seen from Figure 1, the maximum absorption wavelength of the material is at 392nm; its fluorescence emission spectrum has two peaks, respectively at 427nm and 474nm; as can be seen from Figure 2, the peak of the electroluminescence spectrum of the material is at 472nm, and 423nm also has a shoulder.

Detailed ways

Example 1: 2,7-dibromo-9-decyl-9-(2-(4-amino-1,8-naphthalimide-9-)ethyl-1-)fluorene

Under the protection of a nitrogen atmosphere, 2.12g (10.0mmol) of 4-amino-1,8-naphthalimide was dissolved in 60ml of dimethyl sulfoxide, and then 0.84g (15.0mmol) of powdered Potassium hydroxide, react at 50°C for ten minutes under electromagnetic stirring, then gradually add 3.426g (6.0mmol) 2,7-dibromo-9-decyl-9-(2-bromoethyl-1-) to the system fluorene. Reacted for 14 hours, washed repeatedly after chloroform extraction, dried, filtered, and column chromatography separated the product to obtain the pure intermediate product 2,7-dibromo-9-decyl-9-(2-(4-amino-1,8-naphthalene Imide-9-)ethyl-1-)fluorene 2.99g, yield 71%.

Example 2: 2,7-dibromo-9-decyl-9-(2-(4-dimethylamino-1,8-naphthalimide-9-)ethyl-1-)fluorene

Under the protection of nitrogen atmosphere, 0.351g (0.5mmol) 2,7-dibromo-9-decyl-9-(2-(4-amino-1,8-naphthalimide-9-)ethyl- 1-) Dissolve fluorene in 10 ml of dimethyl sulfoxide, then add 0.040 g (1 mmol) of 60% sodium hydride to the solution, react at 0°C for 10 minutes under electromagnetic stirring, and then add 0.71 g (5.0 mmol) to the system Iodomethane, reacted for 3 hours, washed repeatedly after chloroform extraction, dried, filtered, and the product was separated by column chromatography to obtain pure intermediate product 2,7-dibromo-9-decyl-9-(2-(4-dimethylamino -1,8-Naphthoimide-9-)ethyl-1-)fluorene 0.356 g, yield 92%.

Example 3: 2,7-dibromo-9,9-(10-(4-amino-1,8-naphthalimide-9-)decyl-1-)fluorene

Under the protection of a nitrogen atmosphere, 2.12g (10.0mmol) of 4-amino-1,8-naphthalimide was dissolved in 60ml of dimethyl sulfoxide, and then 0.56g (10.0mmol) of powdered Potassium hydroxide, reacted at 150°C for ten minutes under electromagnetic stirring, then gradually added 0.381g (5.0mmol) 2,7-dibromo-9,9-(10-bromodecyl-1-)fluorene to the system, and reacted After 14 hours, chloroform was extracted and washed repeatedly, dried, filtered, and the product was separated by column chromatography to obtain the pure intermediate product 2,7-dibromo-9,9-(10-(4-amino-1,8-naphthalimide- 9-)decyl-1-)fluorene 2.867g, yield 56%.

Example 4: 2,7-dibromo-9,9-(10-(4-didecylamino-1,8-naphthalimide-9-)decyl-1-)fluorene

Under the protection of nitrogen atmosphere, 0.512g (0.5mmol) 2,7-dibromo-9-decyl-9-(2-(4-amino-1,8-naphthalimide-9-)ethyl- 1-) Dissolve fluorene in 10 ml of dimethyl sulfoxide, then add 0.40 g (10 mmol) of 60% sodium hydride to the solution, react at 60°C for 10 minutes under electromagnetic stirring, and then add 1.105 g (5.0 mmol) to the system 1-bromodecane, reacted for 3 hours, extracted with chloroform, washed repeatedly, dried, filtered, and separated by column chromatography to obtain pure intermediate product 2,7-dibromo-9,9-(10-(4-didecylamino -1,8-naphthalimide-9-)decyl-1-)fluorene 0.209g, yield 32%.

Example 5: 2,7-dibromo-9-decyl-9-(2-(4-(carbazolyl-N-)1,8-naphthalimide-9-)ethyl-1-) Synthesis of fluorene

Under the protection of nitrogen atmosphere, 0.362g (1mmol) 4-(carbazolyl-N-)-1,8-naphthalimide was dissolved in 100ml dimethyl sulfoxide, and 0.168g (3.0mmol) was added to the solution ) powdered potassium hydroxide, reacted at 90°C for ten minutes under electromagnetic stirring, then gradually added 0.571g (1.0mmol) 2,7-dibromo-9-decyl-9-(2-bromoethyl -1-) fluorene. Reacted for 14 hours, washed repeatedly after chloroform extraction, dried, filtered, and column chromatography separated the product to obtain pure intermediate product 2,7-dibromo-9-decyl-9-(2-(4-(carbazolyl-N- )1,8-naphthalimide-9-)ethyl-1-)fluorene 0.315 g, yield 37%.

Example 6: 2,7-dibromo-9,9-bis(6-(4-(4-methoxyphenyl)1,8-naphthalimide-9-)hexyl-1-)fluorene synthesis

Under the protection of nitrogen atmosphere, 0.606g (2.0mmol) 4-(4-methoxyphenyl)-1,8-naphthalimide was dissolved in 5 milliliters of dimethyl sulfoxide, and then 0.168g ( 3.0mmol) powdered potassium hydroxide, reacted at 50°C for ten minutes under electromagnetic stirring, then gradually added 0.52g (0.8mmol) 2,7-dibromo-9,9-bis(6-bromohexyl- 1-) fluorene, reacted for 14 hours, washed repeatedly after extraction with chloroform, dried, filtered, and the product was separated by column chromatography to obtain the pure intermediate product 2,7-dibromo-9,9-bis(6-(4-(4-methyl Oxyphenyl)-1,8-naphthalimide-9-)hexyl-1-)fluorene 0.149g, yield 17%.

Example 7: 2,7-dibromo-9-hexyl-9-(6-(4-(9,9-dihexylfluorenyl-2-)-1,8-naphthalimide-9-)hexyl -1-)Synthesis of fluorene

Under the protection of nitrogen atmosphere, 1.058g (2.0mmol) of 4-(9,9-dihexylfluorenyl-2-)-1,8-naphthalimide was dissolved in 5ml of dimethyl sulfoxide, and then added to the solution Add 0.56g (10.0mmol) of powdered potassium hydroxide, react at 50°C for ten minutes under electromagnetic stirring, then gradually add 5.71g (10mmol) of 2,7-dibromo-9-hexyl-9-(6 -Bromohexyl-1-)fluorene, reacted for 1 hour, washed repeatedly after extraction with chloroform, dried, filtered, and the product was separated by column chromatography to obtain pure intermediate product 2,7-dibromo-9-hexyl-9-(6-(4 -(9,9-Dihexylfluorenyl-2-)-1,8-naphthalimide-9-)hexyl-1-)fluorene 1.306g, yield 64%.

Example 8: Synthesis of 4-(naphthyl-2-)-1,8-naphthalimide

Under nitrogen atmosphere protection, 13.76g (80mmol) naphthalene-2-boronic acid, 13.80g (50mmol) 4-bromo-1,8-naphthalimide, 13.80g (100mmol) potassium carbonate, 50ml water, 200ml toluene, The mixture of 0.231g (0.02mmol) tetrakis (triphenylphosphine) palladium was stirred and reacted at 80°C for 24 hours, extracted with chloroform, washed repeatedly, dried, filtered, and recrystallized with ethyl acetate after removing the solvent to obtain the pure intermediate product 4 -(Naphthyl-2-)-1,8-naphthalimide 15.02 g, yield 93%.

Example 9: 2,7-dibromo-9-hexyl-9-(6-(4-(naphthyl-2)-1,8-naphthalimide-9-)hexyl-1-)fluorene

Under the protection of a nitrogen atmosphere, 0.646g (2.0mmol) of 4-(naphthyl-2)-1,8-naphthalimide was dissolved in 5 ml of dimethyl sulfoxide, and then 0.168g (3.0mmol) was added to the solution Powdered potassium hydroxide was reacted at 20°C for ten minutes under electromagnetic stirring, and then 5.71g (10mmol) of 2,7-dibromo-9-hexyl-9-(6-bromohexyl-1-) was gradually added to the system Fluorene, reacted for 50 hours, washed repeatedly after extraction with chloroform, dried, filtered, and the product was separated by column chromatography to obtain the pure intermediate product 2,7-dibromo-9-hexyl-9-(6-(4-(naphthyl-2) -1.09 g of -1,8-naphthalimide-9-)hexyl-1-)fluorene, yield 67%.

Example 10: Synthesis of 2,7-dibromo-9-propyl-9-(2-(4-methoxy-1,8-naphthalimide-9-)ethyl-1-)fluorene

Under the protection of a nitrogen atmosphere, 2.27g (10.0mmol) of 4-methoxy-1,8-naphthalimide was dissolved in 60ml of dimethyl sulfoxide, and then 0.84g (15.0mmol) of powder was added to the solution Potassium hydroxide, reacted at 50°C for ten minutes under electromagnetic stirring, then gradually added 2.838g (6.0mmol) 2,7-dibromo-9-propyl-9-(2-bromoethyl-1- ) fluorene. Reaction for 14 hours, repeated washing after chloroform extraction, drying, filtration, and column chromatography to obtain pure intermediate product 2,7-dibromo-9-hexyl-9-(2-(4-methoxy-1,8- Naphthalimide-9-)ethyl-1-)fluorene 2.637g, yield 71%.

Example 11:

Under nitrogen protection, add 0.2736g (0.499mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethyleneborate)fluorene, 0.0007g (0.001mmol) 2,7-dibromo-9-decyl-9-(2-(4-dimethylamino-1,8-naphthoylidene Amine-9-)ethyl-1-)fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5mL water, 7mL toluene, 0.009g Aliquat 336 mixture, react at 80°C for ten minutes, then add 0.0115 g (0.01 mmol) tetrakis (triphenylphosphine) palladium, stirred and reacted at 100°C for 12 hours, the reaction mixture was dissolved in chloroform, washed once with aqueous solution of ferric chloride, washed with water several times, dried, concentrated, then settled three times with methanol, The product was placed in a Soxhlet extractor, extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.253 g of a pale yellow solid, with a yield of 65%. The properties of the product are as follows: the number-average molecular weight is 32,200, and the absorption spectrum and fluorescence spectrum of the film formed by spin-coating the polymer on a quartz substrate are shown in Fig. 1 .

The assembly conditions of single-layer devices (device structure: ITO/PEDOT/Polymer/Ca/Al) are as follows: use pre-cleaned ITO glass as the anode, and then spin-coat a layer of conductive polymer-polythiophene derivatives (PEDOT) (50nm ). After the PEDOT-modified ITO was vacuum-dried at 150° C. for 3 hours, a chloroform solution with a concentration of 10 mg/ml polymer was spin-coated on the ITO surface at a speed of 1500 rpm. Subsequently, 10 nm of metallic calcium and 100 nm of metallic aluminum were evaporated under high vacuum conditions. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 3.8 volts, the maximum brightness is 6700cd/ ^m2 , and the maximum electroluminescence efficiency is 4.4cd/A. The electroluminescence spectrum is shown in Figure 2, and its color coordinates (0.14, 0.20 ).

Example 12:

Under nitrogen protection, add 0.2194g (0.40mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.50mmol) 9,9-dioctyl-2,7 -(trimethyleneborate)fluorene, 0.0730g (0.10mmol) 2,7-dibromo-9-decyl-9-(2-(4-dimethylamino-1,8-naphthoylidene Amine-9-)ethyl-1-)fluorene, 0.276g (2.0mmol) potassium carbonate, 1.0mL water, 7mL toluene, 0.004g Aliquat 336 mixture, react at 60°C for ten minutes, then add 0.0012 g (0.001mmol) tetrakis(triphenylphosphine) palladium, stirred and reacted at 60°C for 120 hours, the reaction mixture was dissolved in chloroform, washed several times with water, dried, concentrated, then settled three times with methanol, and the product was placed in a Soxhlet extractor , extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.215 g of a pale yellow solid, with a yield of 53%. The properties of the product are as follows: the number-average molecular weight is 26,700, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 486nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 11.6 volts, the maximum brightness is 711 cd/m ² , the maximum electroluminescence efficiency is 0.74 cd/A, and the color coordinates are (0.20, 0.48).

Example 13:

Under the protection of nitrogen, add 0.2792g (0.500mmol) 9,9-dioctyl-2,7-(trimethylene borate group) fluorene, 0.3514g (0.500mmol) 2,7-bis Bromo-9-decyl-9-(2-(4-dimethylamino-1,8-naphthalimide-9-)ethyl-1-)fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5 The mixture of mL water and 6 mL toluene was reacted at 80° C. for ten minutes, then 0.0115 g (0.01 mmol) tetrakis(triphenylphosphine) palladium was added to the reaction flask, stirred and reacted at 50° C. for 120 hours, and the reaction mixture was dissolved in chloroform. It was washed with water several times, dried, concentrated, and settled three times with methanol. The product was placed in a Soxhlet extractor, extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.226 g of a pale yellow solid, with a yield of 47%. The properties of the product are as follows: the number-average molecular weight is 15,400, the maximum ultraviolet absorption of the film is 397nm, and the solid-state fluorescence emission peak is 517nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 8.6 volts, the maximum brightness is 543 cd/m ² , the maximum electroluminescence efficiency is 0.78 cd/A, and the color coordinates are (0.26, 0.58).

Example 14:

Under nitrogen protection, add 0.2739g (0.4995mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethylene borate)fluorene, 0.0007g (0.0005mmol) 2,7-dibromo-9,9-(10-(4-didecylamino-1,8-naphthalimide-9 -)decyl-1-)fluorene, 1.38g (10.0mmol) potassium carbonate, 5mL water, 7mL toluene, 0.21g Aliquat 336 mixture, react at 80°C for ten minutes, then add 0.0115g (0.01mmol) to the reaction flask ) tetrakis (triphenylphosphine) palladium, stirred and refluxed for 12 hours, the reaction mixture was dissolved in chloroform, washed several times, dried, concentrated, then settled three times with methanol, the product was placed in a Soxhlet extractor, extracted with acetone 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.252 g of a pale yellow solid, with a yield of 65%. The properties of the product are as follows: the number-average molecular weight is 31,000, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 468nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 3.5 volts, the maximum brightness is 6641cd/m ² , the maximum electroluminescent efficiency is 2.58cd/A, and the color coordinates are (0.16, 0.18).

Example 15:

Under nitrogen protection, add 0.2632g (0.48mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethyleneborate)fluorene, 0.0174g (0.02mmol) 2,7-dibromo-9-decyl-9-(2-(4-(carbazolyl-N-)1,8- Naphthalimide-9-)ethyl-1-)fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5mL water, 7mL toluene, the mixture of 0.08g Aliquat 336, react at 80°C for ten minutes, and then pour into the reaction bottle Add 0.0115g (0.01mmol) tetrakis (triphenylphosphine) palladium, 100 ℃ stirring reaction for 12 hours, the reaction mixture was dissolved in chloroform, washed several times, dried, concentrated, and then settled three times with methanol, the product was placed in the Extractor, extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.253 g of a pale yellow solid, with a yield of 65%. The properties of the product are as follows: the number-average molecular weight is 24,000, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 481nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 7.6 volts, the maximum brightness is 341 cd/m ² , the maximum electroluminescence efficiency is 0.38 cd/A, and the color coordinates are (0.20, 0.26).

Example 16:

Under nitrogen protection, add 0.2740g (0.4998mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethyleneborate)fluorene, 0.0002g (0.0002mmol) 2,7-dibromo-9,9-bis(6-(4-(4-methoxyphenyl)1,8-naphthalene Imide-9-)hexyl-1-)fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5mL water, 7mL toluene, 0.08g Aliquat 336 mixture, react at 80°C for ten minutes, then add 0.0115g (0.01mmol) tetrakis (triphenylphosphine) palladium, stirred and reacted at 90°C for 12 hours, dissolved the reaction mixture in chloroform, washed once with aqueous solution of ferric chloride, washed with water several times, dried, concentrated, and settled with methanol three times , the product was placed in a Soxhlet extractor, extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.221 g of a pale yellow solid, with a yield of 57%. The properties of the product are as follows: the number average molecular weight is 32,800, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 421nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 11.6 volts, the maximum brightness is 541 cd/m ² , the maximum electroluminescence efficiency is 1.21 cd/A, and the color coordinates are (0.16, 0.12).

Example 17:

Under nitrogen protection, add 0.2725g (0.497mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethyleneborate)fluorene, 0.0031g (0.003mmol) 2,7-dibromo-9-hexyl-9-(6-(4-(9,9-dihexylfluorenyl-2)- 1,8-naphthoimide-9-)hexyl-1-)fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5mL water, 7mL toluene, the mixture of 0.08g Aliquat 336, react at 80 ℃ for ten minutes, then Add 0.0115g (0.01mmol) tetrakis(triphenylphosphine) palladium to the reaction flask, stir and react at 100°C for 12 hours, dissolve the reaction mixture with chloroform, wash once with aqueous ferric chloride, wash with water several times, dry, concentrate, Then it was settled three times with methanol, and the product was placed in a Soxhlet extractor, extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.253 g of a pale yellow solid, with a yield of 65%. The properties of the product are as follows: the number-average molecular weight is 32,000, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 443nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 4.6 volts, the maximum brightness is 4623 cd/m ² , the maximum electroluminescence efficiency is 3.64 cd/A, and the color coordinates are (0.16, 0.15).

Example 18:

Under nitrogen protection, add 0.2736g (0.499mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethyleneborate)fluorene, 0.0008g (0.001mmol) 2,7-dibromo-9-hexyl-9-(6-(4-(naphthyl-2)-1,8-naphthoyl The mixture of imine-9-)hexyl-1-)fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5mL water, 7mL toluene, 0.08g Aliquat 336 was reacted at 80°C for ten minutes, and then 0.115 g (0.1 mmol) tetrakis(triphenylphosphine)palladium, stirred at 80°C for 12 hours, the reaction mixture was dissolved in chloroform, washed several times with water, dried, concentrated, then settled three times with methanol, and the product was placed in a Soxhlet extractor , extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.279 g of a pale yellow solid, with a yield of 72%. The properties of the product are as follows: the number-average molecular weight is 37,800, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 435nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 3.6V, the maximum brightness is 4520cd/m ² , the maximum electroluminescence efficiency is 1.78cd/A, and the color coordinates are (0.16, 0.14).

Example 19:

Under nitrogen protection, add 0.2736g (0.499mmmol) 9,9-dioctyl-2,7-dibromofluorene, 0.2792g (0.5mmol) 9,9-dioctyl-2,7 -(trimethylene borate)fluorene, 0.0006g (0.001mmol) 2,7-dibromo-9-propyl-9-(2-(4-methoxy-1,8-naphthalimide -9-) ethyl-1-) fluorene, 0.4140g (3.0mmol) potassium carbonate, 1.5mL water, 7mL toluene, 0.08g Aliquat 336 mixture, react at 80°C for ten minutes, then add 0.0115g to the reaction flask (0.01mmol) tetrakis (triphenylphosphine) palladium, stirred and reacted for 12 hours at 120° C., the reaction mixture was dissolved in chloroform, washed once with aqueous solution of iron trichloride, washed with water several times, dried, concentrated, then settled three times with methanol, and The product was placed in a Soxhlet extractor, extracted with acetone for 24 hours, then dissolved in chloroform and settled in methanol. The product was dried in vacuo to obtain 0.253 g of a pale yellow solid, with a yield of 65%. The properties of the product are as follows: the number-average molecular weight is 22,600, the maximum ultraviolet absorption of the film is 392nm, and the solid-state fluorescence emission peak is 440nm.

The single-layer device assembly conditions are the same as in Example 11. The performance of the single-layer electroluminescent device is as follows: the starting voltage is 4.6 volts, the maximum brightness is 2141 cd/m ² , the maximum electroluminescence efficiency is 1.28 cd/A, and the color coordinates are (0.16, 0.13).

Claims (1)

1. A blue electroluminescent polymer polyfluorene material, characterized in that it has the following structure: or Wherein: R ₁ is selected from hexyl, octyl, phenyl or 4-(diphenylamino) phenyl substituted by an alkyl group with 1-10 carbon atoms; R ₂ is selected from hydrogen or 1-10 carbon atoms Alkyl group of 10; Ar is a naphthalimide derivative radical, selected from one or both of the following structural units:

Wherein, _R3 is selected from hydrogen or an alkyl group with 1-10 carbon atoms, _R4 is selected from hydrogen; X is selected from oxygen atom or sulfur atom; 1≤p≤5; x is the content of naphthalimide units, satisfying 0<x≤1, m=1-20, n=1-300.

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