CN105924629A - Conjugated polymer based on naphthoindenofluorene unit as well as preparation method and application thereof - Google Patents

Abstract

The invention discloses a conjugated polymer based on a naphthoindenofluorene unit as well as a preparation method and application thereof. The naphthoindenofluorene is high in planarity, high in fluorescent quantum yield and high in solubility, can be used for preparing a homopolymer or a copolymer through Suzuki polymerization reaction, and is suitable for solution processing and printing display. The prepared conjugated polymer based on naphthoindenofluorene can be applied to light-emitting layers of organic light-emitting diodes.

Description

A kind of conjugated polymer based on naphthoindene fluorene unit and its preparation method and application

technical field

The invention belongs to the field of organic photoelectric technology, and specifically relates to a conjugated polymer based on naphthoindene fluorene units, a preparation method and application thereof.

Background technique

In the past three decades, organic electronics and optoelectronics industries, including organic/polymer light-emitting diodes, organic field-effect transistors, organic solar cells, etc., have developed rapidly and gradually realized industrialization. Organic electronic products have the advantages of low price, light weight and portability. Make it have great market potential. Therefore, the development of market-attractive organic electronic products has attracted the attention of many research institutions and scientific research teams in the world, and among them, the development of new efficient and stable materials has become the key.

The naphthoindene fluorene unit and its polymer involved in the present invention are suitable for solution processing because of their good solubility and good fluorescence quantum yield. The light-emitting device is not only efficient and stable, but also bluer Saturated blue light can meet the requirements of full-color display. Therefore, there is great development potential and prospect in the field of organic electronic display.

Contents of the invention

The object of the present invention is to provide a conjugated polymer based on naphthoindene fluorene unit (NIF) for the problems faced by the current polymer light-emitting diode (PLED), which can be used as a light-emitting material, and this type of material has better solubility properties, high fluorescence quantum yield, suitable for solution processing and inkjet printing, and has good development prospects.

The object of the present invention is also to provide a preparation method of the conjugated polymer based on naphthoindene fluorene units.

The object of the present invention is also to provide the application of the conjugated polymer based on naphthoindene fluorene units in light-emitting diodes.

A conjugated polymer based on naphthoindene fluorene units, the chemical structural formula is as follows:

In the formula, R is a linear or branched alkyl group or alkoxy group or H atom or aryl group or triphenylamine with 1-20 carbon atoms.

Further, the structure of Ar is any one of the following structures:

2,7-substituted fluorene;

3,6-substituted fluorene;

2,7-substituted silafluorene;

3,6-substituted silafluorene;

2,7-substituted spirofluorene;

3,6-substituted spirofluorene;

2,7-substituted-9,9-dialkoxyphenylfluorene;

3,6-substituted-9,9-dialkoxyphenylfluorene;

2,7-substituted carbazoles;

3,6-substituted carbazoles;

2,6-substituted-dithienosilole;

2,6-substituted-dithienocyclopentadiene;

2,5-substituted pyridine;

2,6-substituted pyridine;

3,5-substituted pyridine;

3,5-bis(4-substituted-phenyl)-4-yl-1,2,4-triazole;

3,5-bis(4-substituted-phenyl)-1,2,4-oxadiazole;

4,7-bis(5-substituted-4-alkylthienyl)-2,1,3-benzothiadiazole;

4,7-bis(5-substituted-4-alkylthienyl)2,1,3-benzoselenadiazole;

4,7-substituted-5,6-alkyl-2,1,3-benzothiadiazoles;

4,7-substituted-5,6-alkyl-2,1,3-benzoselenadiazole;

2,5-substituted-3,4-dialkylthiophene;

2,5-substituted-3,4-dialkylselenophene;

5,5-substituted-4,4-dialkyl-bithiophenes;

Indenfluorene;

Indolecarbazole;

4,9-substituted-6,7-alkyl-naphthothiadiazoles;

4,9-substituted-6,7-alkyl-naphthoselenadiazole;

Wherein, R is a straight chain or branched chain alkyl group or alkoxy group or H atom or aryl group or triphenylamine with 1-20 carbon atoms.

The above-mentioned preparation method of a conjugated polymer based on naphthoindene fluorene (NIF) units mainly includes the preparation of naphthoindene fluorene and the synthesis of the polymer based on naphthoindene fluorene. Using fluorene as a raw material, fluorene has a high fluorescence quantum yield and is easy to process in solution. It is a very promising blue light material. First, 1-bromo-2-naphthoic acid is esterified to generate 1-bromo-2-naphthoic acid methyl ester, and then Suzuki coupling occurs with 2-boronate-9,9-dioctylfluorene, and then the column Purify by chromatography, and then dissolve the obtained monomer in anhydrous tetrahydrofuran, then add the ether solution of alkyl bromide Grignard reagent, after the reaction is completed, treat and extract with saturated ammonium chloride aqueous solution, and the crude product is subjected to column chromatography Purify. Then add dichloromethane to dissolve the monomer, and then add boron trifluoride ether solution to carry out Friedel-Crafts alkylation reaction to close the ring. After the reaction, it was treated with saturated aqueous ammonium chloride solution, extracted, and the crude product was purified by column chromatography. Then the obtained monomer can be reacted by bromination to obtain naphthoindene fluorene (NIF) monomer. Then a series of conjugated polymers were synthesized by Suzuki polymerization method.

The application of the above-mentioned polymer materials in light-emitting diodes and flat panel displays.

The above-mentioned conjugated polymer based on naphthoindene fluorene units can be dissolved in common organic solvents. It can be used as a light-emitting layer of a light-emitting diode, and the conjugated polymer is dissolved with an organic solution, and then formed into a film by spin coating, ink-jet printing or printing.

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

(1) The conjugated polymer based on the naphthoindene fluorene unit prepared by the present invention has a larger conjugate length and better planarity, so it has a higher fluorescence quantum yield, which is conducive to improving the device of the material efficiency.

(2) The conjugated polymer based on the naphthoindene fluorene unit prepared by the present invention has good solubility, and when it is used as a light-emitting layer, no annealing treatment is required in the preparation of the device, which makes the preparation process simpler.

Description of the drawings:

Fig. 1 is the thermal analysis spectrogram of polymer PFNIF.

Fig. 2 is the ultraviolet-visible absorption spectrum and the fluorescence spectrum of the polymer PFNIF in the thin film state.

Figure 3 is the electroluminescent spectrum of polymer PFNIF.

Figure 4 is the cyclic voltammetry (CV) spectrum of polymer PCzNIF.

Fig. 5 is the lumen efficiency-current density curve of polymer PBTNIF.

Fig. 6 is the lumen efficiency-current density curve of polymer PDTBTNIF.

detailed description

The present invention will be described in further detail below in conjunction with the examples, but the embodiments of the present invention are not limited thereto.

The preparation of embodiment 1 2-bromofluorene

In a 250 mL three-necked flask, add fluorene (16.6 g, 0.1 mol), iron powder (88 mg, 1.57 mmol), and 100 mL of chloroform. After cooling in an ice-water bath, 35 mL of a bromine (17.6 g, 0.1 mol)/chloroform mixed solution was added dropwise. The temperature in the bottle does not exceed 5°C during the dropwise addition. After reacting for 16 hours, stop the reaction, filter and recrystallize from chloroform to obtain 19.3 g of white solid with a yield of 84%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 2 Preparation of 2-bromo-9,9-dioctylfluorene

2-Bromofluorene (7.4 g, 0.03 mol), benzyltriethylammonium chloride (0.07 g, 0.3 mmol), 90 mL of dimethyl sulfoxide, and 45 mL of aqueous sodium hydroxide solution (50 wt %) were added to a three-necked flask. Stir at room temperature to form a suspension. 1-Bromo-n-octane (12.5 g, 65 mmol) was added dropwise, and stirring was continued for 3 hours, followed by extraction with ether. The ether phase was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate. The solvent was evaporated, and the product was purified by column chromatography using petroleum ether as the eluent to obtain a white solid. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 3 Preparation of 2-boronate-9,9-dioctylfluorene

Under an argon atmosphere, 2-bromo-9,9-dioctylfluorene (5 g, 10.65 mmol) was dissolved in 180 mL of refined THF, and 1.6 mol.L ^-1 of n-butyl was gradually added dropwise at -78 °C Base lithium 28mL, react for 2 hours, then add 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborane 25mL, continue reaction at -78°C for 1 hours, warming up to room temperature and reacting for 24 hours. The reaction mixture was poured into water, extracted with ethyl acetate, and the organic layer was washed with brine and dried over anhydrous magnesium sulfate. After the solution was concentrated, a light yellow viscous crude product was obtained, which was purified by silica gel column chromatography (petroleum ether/ethyl acetate = 20/1, v/v was selected as the eluent). The product was placed in the refrigerator for a long time to obtain a white solid, the product rate of 70%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 4 Methyl 1-bromo-naphthoate

Under an argon atmosphere, add 1-bromo-2-naphthoic acid (10g, 39.83mmol) into a two-necked flask, add 100mL of methanol, then add concentrated sulfuric acid (39.06mg, 398.29umol) dropwise, and heat to 110°C. Reaction 18h. The reaction mixture was poured into water, extracted with ethyl acetate, and the organic layer was washed with brine and dried over anhydrous magnesium sulfate. After the solution was concentrated, a white solid crude product was obtained, which was purified by silica gel column chromatography (petroleum ether/dichloromethane=3/1, v/v was selected as the eluent), and the product was placed in the refrigerator for a long time to obtain a white solid with a yield of 85%. . ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

The preparation of embodiment 5 compound M1

Under an argon atmosphere, 2-boronate-9,9-dioctylfluorene (5g, 9.68mmol) and methyl 1-bromo-naphthoate (2.69g, 10.16mmol) were added into a two-necked flask, and then Add 100ml of toluene to dissolve it completely, then add sodium carbonate (5.13g, 43.89mmol) and tetrabutylammonium bromide (312.01mg, 967.86umol), and react at 110°C for 18h. The reaction mixture was poured into water, extracted with ethyl acetate, and the organic layer was washed with brine and dried over anhydrous magnesium sulfate. After the solution was concentrated, it was purified by silica gel column chromatography (petroleum ether/dichloromethane=5/1, v/v was selected as the eluent), and finally a white solid was obtained with a yield of 80%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

The preparation of embodiment 6 compound M2

Under argon atmosphere, M1 (5 g, 8.70 mmol) was added into a one-necked bottle, and then 50 ml of anhydrous THF was added until it was completely dissolved. Then react the reaction liquid at 0° C. for 1 h, then add C ₈ H ₁₇ MgBr (n-octylmagnesium bromide) dropwise, and react the mixture at room temperature for 18 h. Water was added to the reaction solution to quench the reaction, extracted with ethyl acetate, the organic layer was washed with brine, and dried over anhydrous magnesium sulfate. After the solution was concentrated, it was purified by silica gel column chromatography (petroleum ether/dichloromethane=3/1 as eluent, v/v), and the product was placed in the refrigerator for a long time to obtain a white solid with a yield of 80%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

The preparation of embodiment 7 compound M3

Under an argon atmosphere, M2 (5 g, 6.48 mmol) was dissolved in 50 ml of dichloromethane, and boron trifluoride ether solution (439.59 mg, 6.48 mmol) was added dropwise at room temperature, and reacted for 18 h. It was extracted with ethyl acetate, and the organic layer was washed completely with brine, and dried over anhydrous magnesium sulfate. After the solution was concentrated, it was purified by silica gel column chromatography (petroleum ether was selected as the eluent). The product was placed in the refrigerator for a long time to obtain a white solid with a yield of 90%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

The preparation of embodiment 8 naphthoindene fluorene (NIF)

Under an atmosphere of argon, M3 (5g, 6.64mmol) was dissolved in 50mL of dichloromethane, then iron powder (185.35mg, 3.32mmol) was added, and liquid bromine (1.06g, 6.64mmol) was added dropwise, at room temperature Under reaction 18h. It was extracted with ethyl acetate, and the organic layer was washed completely with brine, and dried over anhydrous magnesium sulfate. After the solution was concentrated, it was purified by silica gel column chromatography (petroleum ether was selected as the eluent), and the yield was 70%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 9 Preparation of 2,7-dibromofluorene

In a 250 mL three-necked flask, add fluorene (24.5 g, 0.1 mol), iron powder (88 mg, 1.57 mmol), and 100 mL of chloroform. After cooling in an ice-water bath, 35 mL of a bromine (17.6 g, 0.1 mol)/chloroform mixed solution was added dropwise. The temperature in the bottle does not exceed 5°C during the dropwise addition. After the reaction was completed, it was filtered and recrystallized from chloroform to obtain 20.3 g of a white solid with a yield of 83%. ¹ HNMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 10 Preparation of 2,7-dibromo-9,9-dioctylfluorene

Add 2,7-dibromofluorene (9.7g, 0.03mol), benzyltriethylammonium chloride (0.07g, 0.3mmol), dimethyl sulfoxide 90mL, 45mL sodium hydroxide aqueous solution (50wt %). Stir at room temperature to form a suspension. 1-Bromo-n-octane (12.5 g, 65 mmol) was added dropwise, and stirring was continued for 3 hours, followed by extraction with ether. The ether phase was washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate. The solvent was evaporated, and the product was purified by column chromatography using petroleum ether as the eluent to obtain a white solid. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 11 Preparation of 2,7-diboronate-9,9-dioctylfluorene

Under an argon atmosphere, 2,7-dibromo-9,9-dioctylfluorene (5 g, 9.12 mmol) was dissolved in 180 mL of refined THF, and 1.6 mol.L ^-1 was gradually added dropwise at -78°C 28mL of n-butyllithium, reacted for 2 hours, then added 25mL of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborane, at -78°C The reaction was continued for 1 hour, and then the temperature was raised to room temperature for 24 hours. The reaction mixture was poured into water, extracted with ethyl acetate, and the organic layer was washed with brine and dried over anhydrous magnesium sulfate. After the solution was concentrated, a light yellow viscous crude product was obtained, which was purified by silica gel column chromatography (petroleum ether/ethyl acetate = 15/1, v/v was selected as the eluent), and the product was placed in the refrigerator for a long time to obtain a white solid. rate of 70%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 12 Preparation of 3,6-dibromocarbazole

Add carbazole (24.7g, 0.1mol) and 200mL dimethylformamide to a 500mL two-necked flask, stir until completely dissolved, NBS (49.84g, 0.28mol) is dissolved in 120ml N, N-dimethylformamide, ice Bath to 0°C, add NBS solution dropwise, react, avoid light, after the dropwise addition, let the temperature rise to room temperature automatically, react for 6 hours, add the reaction solution dropwise to water to precipitate, after the crude product is obtained by suction filtration, the The product was recrystallized with absolute ethanol and dried to obtain a needle-like solid with a yield of 85%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 13 3,6-dibromo-N-octylcarbazole

Add 3,6-dibromocarbazole (16.25g, 0.05mmol), 100mL toluene, and tetrabutylammonium bromide (0.8g, 3.5mmol) into a 250mL three-necked flask and stir to dissolve, then add 11mL of 50wt% KOH aqueous solution dropwise, Then add bromooctane (19.3g, 0.1mol), react at 80°C for 24 hours, add water to terminate the reaction, wash the separated organic phase with water, extract the aqueous phase with dichloromethane, combine the organic phases, and wash with anhydrous MgSO _4. After drying, the solvent was distilled off under reduced pressure to obtain a light yellow solid, which was recrystallized from petroleum ether to obtain a white powder solid. Yield 90%. ¹ H NMR, ¹³ CNMR, MS and elemental analysis results show that the obtained compound is the target product, and its chemical reaction equation is as follows:

Example 14 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-N-octylcarbazole

Add 3,6-dibromo-N-octylcarbazole (13.11g, 30mmol) and 250mL of freshly distilled diethyl ether into the three-necked flask, stir to dissolve completely until it is clear and transparent, then cool the reaction solution to -78°C, and then Add 2-isopropoxy-(4,4,5,5-tetramethyl)-1,3,2-ethanedioxy borate (37mL, 180mmol) and stir at -78°C for 2 hours , and then the temperature was raised to room temperature and the reaction was completed after 24 hours. Extracted with ether, washed with saturated brine for 4 times, dried with anhydrous magnesium sulfate, filtered, and evaporated to remove the solvent, the product was purified by column chromatography with petroleum ether/ethyl acetate (10:1) as the eluent to obtain a white Solid, 45% yield.

The synthesis of embodiment 15 polymer PFNIF

Under an argon atmosphere, add 2,7-diboronate-9,9-dioctylfluorene (200mg, 311.2μmol) and naphthoindene fluorene (283.56mg, 311.2μmol) into a 100ml two-necked bottle, and then add Dissolve 8ml of toluene completely, pump and vent three times, then add palladium acetate (2.80mg, 12.45μmol) and tricyclohexylphosphine (6.98mg, 24.90μmol), pump and vent three times, then add 2ml of tetraethylammonium hydroxide , heated up to 80°C, and reacted for 24 hours. Then 30 mg of phenylboronic acid was added for capping, and after 12 hours, 0.1 ml of bromobenzene was used for capping. After continuing to react for 12 hours, add the product dropwise to methanol to precipitate, stir, filter, and then dissolve the crude product in 20 mL of toluene, use 200-300 mesh silica gel as the stationary phase, and use toluene as the eluent for column chromatography. After analysis, the solvent was concentrated under reduced pressure, and precipitated in methanol again, stirred, filtered, and vacuum-dried to obtain a polymer solid. Finally, extract 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 PFNIF was obtained after vacuum drying.

The thermal analysis diagram of the polymer PFNIF obtained in this example is shown in Figure 1, from which we can see that its decomposition temperature (Td) is 405°C, so the polymer has relatively high thermal stability. The ultraviolet-visible absorption spectrum of polymer PFNIF in toluene solution is shown in Figure 2. It can be seen from the figure that the absorption peaks of the polymer are at 346nm and 417nm, and the peak of the photoluminescence spectrum of the polymer is at 464nm. The electroluminescence spectrum of the polymer PFNIF is shown in Figure 3, and it can be seen from the figure that the peak of the electroluminescence spectrum of the polymer is at 508nm.

The synthesis of embodiment 16 polymer PCzNIF

Under an argon atmosphere, 3,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-N-octylcarbazole (200 mg, 376.4μmol) and naphthoindene fluorene (342.92mg, 376.41μmol) were added to a 100ml two-necked bottle, then 8ml of toluene was added to dissolve it completely, and the air was pumped three times, then palladium acetate (3.38mg, 15.06μmol) and tricyclohexyl Phosphine (8.44 mg, 30.11 μmol) was ventilated three times, then 2 ml of tetraethylammonium hydroxide was added, the temperature was raised to 80 degrees Celsius, and the reaction was carried out for 24 hours. Then 30 mg of phenylboronic acid was added for capping, and after 12 hours, 0.1 ml of bromobenzene was used for capping. After continuing to react for 12 hours, add the product dropwise to methanol to precipitate, stir, filter, and then dissolve the crude product in 20 mL of toluene, use 200-300 mesh silica gel as the stationary phase, and use toluene as the eluent for column chromatography. After analysis, the solvent was concentrated under reduced pressure, and precipitated in methanol again, stirred, filtered, and vacuum-dried to obtain a polymer solid. Finally, extract 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 PCzNIF was obtained after vacuum drying.

The cyclic voltammetry curve of the polymer PCzNIF obtained in this embodiment is shown in Figure 4. We calculated the highest occupied molecular orbital energy level (E _HOMO ) and the lowest unoccupied molecular orbital energy level (E _LUMO ) of the polymer by CV test. ). Wherein, since the oxidation-reduction potential of ferrocene (Fc) has an absolute vacuum energy level of 4.8ev, it is used as a benchmark in the electrochemical test process, through the formula E _HOMO =-e(E _OX +4.8-E _fer ) and E _LUMO =-(E _red +4.8-E _fer ) can calculate the HOMO and LUMO energy levels of the polymer, as can be seen from the test chart in Figure 4, the oxidation and reduction potentials of the polymer PCzNIF are 0.86ev and -2.4ev respectively, Ferrocene has _Efer = 0.4, so HOMO = -5.26ev and LUMO = -2.0ev are calculated.

The synthesis of embodiment 17 polymer PBTNIF

Under an argon atmosphere, add benzothiadiazole (200mg, 680.4μmol) and naphthoindene fluorene (619.82mg, 376.41μmol) into a 100ml two-necked bottle, then add 8ml of toluene to dissolve it completely, and pump the gas three times. Palladium acetate (6.11 mg, 27.21 μmol) and tricyclohexylphosphine (15.26 mg, 54.43 μmol) were added, and the gas was ventilated three times, then 2 ml of tetraethylammonium hydroxide was added, the temperature was raised to 80 degrees Celsius, and the reaction was carried out for 24 hours. Then 30 mg of phenylboronic acid was added for capping, and after 12 hours, 0.1 ml of bromobenzene was used for capping. After continuing to react for 12 hours, add the product dropwise to methanol to precipitate, stir, filter, and then dissolve the crude product in 20 mL of toluene, use 200-300 mesh silica gel as the stationary phase, and use toluene as the eluent for column chromatography. After analysis, the solvent was concentrated under reduced pressure, and precipitated in methanol again, stirred, filtered, and vacuum-dried to obtain a polymer solid. Finally, extract 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 PBTNIF was obtained after vacuum drying.

The polymer PBTNIF obtained in this embodiment is based on the device structure: ITO/PEDOT/EML/CsF/Al, and its lumen efficiency-current density curve is shown in Figure 5. From Figure 5, we can see the maximum lumen of the polymer PBTNIF The efficiency is 0.61cd/A.

The synthesis of embodiment 18 polymer PDTBTNIF

Under an argon atmosphere, add bithienobenzothiadiazole (200mg, 436.5μmol) and naphthoindene fluorene (397.64mg, 436.5μmol) into a 100ml two-necked bottle, then add 8ml of toluene to completely dissolve them, and replace Gas three times, then add palladium acetate (3.92mg, 17.461μmol) and tricyclohexylphosphine (9.76mg, 34.92μmol), take a breath three times, then add 2ml tetraethylammonium hydroxide, heat up to 80 degrees Celsius, and react for 24 hours . Then 30 mg of phenylboronic acid was added for capping, and after 12 hours, 0.1 ml of bromobenzene was used for capping. After continuing to react for 12 hours, add the product dropwise to methanol to precipitate, stir, filter, and then dissolve the crude product in 20 mL of toluene, use 200-300 mesh silica gel as the stationary phase, and use toluene as the eluent for column chromatography. After analysis, the solvent was concentrated under reduced pressure, and precipitated in methanol again, stirred, filtered, and vacuum-dried to obtain a polymer solid. Finally, extract 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 PBTNIF was obtained after vacuum drying.

The polymer PDTBTNIF obtained in this embodiment is based on the device structure: ITO/PEDOT/EML/CsF/Al, and its lumen efficiency-current density curve is shown in Figure 6. From Figure 6, we can see the maximum lumen of the polymer PBTNIF The efficiency is 1.35cd/A.

Example 19 Preparation of electroluminescent device based on naphthoindene fluorene polymer

On the pre-made indium tin oxide (ITO) glass, first use acetone, detergent, deionized water and isopropanol to ultrasonically clean, and then plasma treat for 10 minutes. A film of polyethoxythiophene (PEDOT:PSS) doped with polystyrene sulfonic acid (PEDOT:PSS) was spin-coated on ITO with a thickness of 150 nm. The PEDOT:PSS film was dried in a vacuum oven at 80°C for 8 hours. Then the xylene solution (1wt%) of conjugated polymer PFNIF, PCzNIF, PBTNIF, PDTBTNIF is spin-coated on the surface of PEDOT:PSS film, and the thickness is 80nm; Finally, a thin layer of CsF (1.5nm ) and a 120nm thick metal Al layer. Table 1 is the photoelectric performance index of the conjugated polymer based on naphthoindene fluorene unit.

Table 1

It can be seen from Table 1 that the conjugated polymer based on naphthoindene fluorene unit of the present invention is beneficial to improve the device efficiency of the material.

The above-mentioned embodiment is a preferred embodiment of the present invention, but the embodiment of the present invention is not limited by the above-mentioned embodiment, and any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention All should be equivalent replacement methods, and all are included in the protection scope of the present invention.

Claims (4)

1. A conjugated polymer based on naphthoindene fluorene unit, characterized in that, the chemical structural formula is as follows: In the formula, R is a linear or branched alkyl group or alkoxy group or H atom or aryl group or triphenylamine with 1-20 carbon atoms; the degree of polymerization n is 1-300. 2. a kind of conjugated polymer based on naphthoindene fluorene unit according to claim 1, is characterized in that, the structure of described Ar is any one in following structure: 2,7-substituted fluorene; 3,6-substituted fluorene; 2,7-substituted silafluorene; 3,6-substituted silafluorene; 2,7-substituted spirofluorene; 3,6-substituted spirofluorene; 2,7-substituted-9,9-dialkoxyphenylfluorene; 3,6-substituted-9,9-dialkoxyphenylfluorene; 2,7-substituted carbazoles; 3,6-substituted carbazoles; 2,6-substituted-dithienosilole; 2,6-substituted-dithienocyclopentadiene; 2,5-substituted pyridine; 2,6-substituted pyridine; 3,5-substituted pyridine; 3,5-bis(4-substituted-phenyl)-4-yl-1,2,4-triazole; 3,5-bis(4-substituted-phenyl)-1,2,4-oxadiazole; 4,7-bis(5-substituted-4-alkylthienyl)-2,1,3-benzothiadiazole; 4,7-bis(5-substituted-4-alkylthienyl)2,1,3-benzoselenadiazole; 4,7-substituted-5,6-alkyl-2,1,3-benzothiadiazoles; 4,7-substituted-5,6-alkyl-2,1,3-benzoselenadiazole; 2,5-substituted-3,4-dialkylthiophene; 2,5-substituted-3,4-dialkylselenophene; 5,5-substituted-4,4-dialkyl-bithiophenes; Indenfluorene; Indolecarbazole; 4,9-substituted-6,7-alkyl-naphthothiadiazoles; 4,9-substituted-6,7-alkyl-naphthoselenadiazole; R is a straight chain or branched chain alkyl group or alkoxy group or H atom or aryl group or triphenylamine with 1-20 carbon atoms. 3. prepare the method for a kind of conjugated polymer based on naphthoindene fluorene unit described in claim 1, it is characterized in that, the method first carries out esterification with 1-bromo-2-naphthoic acid, generates 1-bromo-2-naphthoic acid Methyl 2-naphthoate is then subjected to Suzuki coupling with 2-boronate-9,9-dioctylfluorene, and then purified by column chromatography. The obtained monomer is dissolved in anhydrous tetrahydrofuran, and then alkyl bromide is added The ether solution of Grignard reagent, after the reaction, was treated with saturated ammonium chloride aqueous solution, extracted, and the crude product was purified by column chromatography, then the obtained monomer was dissolved in dichloromethane, and then boron trifluoride ether solution was added. Carry out a Friedel-Crafts alkylation reaction to close the ring. After the reaction, treat with saturated ammonium chloride aqueous solution, extract, and purify the crude product by column chromatography. The obtained monomer can be brominated to obtain naphthoindene Fluorene monomers, and then synthesize a series of conjugated polymers based on naphthoindene fluorene units by Suzuki polymerization. 4. A kind of conjugated polymer based on naphthoindene fluorene unit described in any one of claim 1-2 is applied to the light-emitting layer of light-emitting diode, it is characterized in that, dissolve described conjugated polymer with organic solvent, then Films are formed by spin coating, inkjet printing or printing methods.