A lithographic light-emitting conjugated polymer, preparation method and application

Abstract

The present invention discloses a photo-lithographable luminescent conjugated polymer, a preparation method and an application, belonging to the field of polymer semiconductor materials. The structural formula of the polymer is shown in Formula I: #imgabs0# wherein, Ar is selected from an aromatic ring, a heteroaromatic ring, an aromatic ring or a heteroaromatic ring containing a long alkyl chain substituent; R1 is selected from one of alkyl chains containing methylene in C1-C50; the number average molecular weight of the polymer is 10,000-100,000. The polymer of the present invention has both excellent optoelectronic properties and photoresist properties, and can directly realize the photolithographic patterning of the luminescent polymer film through the ultraviolet photolithography process.

Description

Technical Field

[0001] The present invention belongs to the field of polymer semiconductor materials, and particularly relates to a photo-lithographable luminescent conjugated polymer with azide groups in the side chain, a preparation method thereof, and an application thereof. Background Art

[0002] Due to the advantages in the manufacturing of large and medium-sized panels and cost, printed display technology has become a hot topic in the field of organic electroluminescence (OLED) in recent years. Among them, light-emitting conjugated polymers have great application potential in the fields of flexible and printed displays due to their excellent optoelectronic properties, solution film-forming characteristics, and unique mechanical properties of polymers. However, how to process the light-emitting polymer thin film into a high-precision, micron-scale pixel array is the key to realizing the application of light-emitting polymers in the printed display industry. Photolithography is the core link in the field of integrated circuit and semiconductor manufacturing. However, the traditional photolithography process requires a photoresist and at least six steps such as exposure, development, etching, and cleaning to prepare a layer of pattern. The process is complex and not suitable for the construction of multi-layer organic structures of organic optoelectronic devices. Therefore, developing a light-emitting polymer material that can be directly and efficiently photo-lithographically patterned is an important way to prepare a high-resolution pixel-level display array by solution printing. Summary of the Invention

[0003] The purpose of the present invention is to provide a photo-lithographable luminescent polymer with azide groups in the side chain, a preparation method thereof, and an application thereof. By introducing azide groups into the side chain of the fluorene structural unit, direct photo-lithographic patterning processing of the light-emitting polymer thin film is realized.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] In the first aspect, the present invention provides a polymer, and its structural formula is shown as Formula I below:

[0006]

[0007] In Formula I, R1 is selected from one of the alkyl chains containing methylene in C1-C50;

[0008] The number-average molecular weight of the polymer shown in Formula I is 10,000-100,000, specifically 15 kDa;

[0009] In Formula I, Ar is selected from an aromatic ring, a heteroaromatic ring, an aromatic ring or a heteroaromatic ring containing a long alkyl chain substituent; preferably, Ar is selected from any one of the following structural formulas:

[0010]

[0011] In the formula, R is selected from any one of the alkyl chains containing methylene in C1-C50;

[0012] represents the bonding position in structural formula I.

[0013] In a second aspect, the present invention provides a method for preparing the polymer of formula I, comprising: subjecting a compound of formula II and a compound of formula III to a carbon-carbon coupling reaction in an organic solvent in the presence of an inert atmosphere and a catalyst to obtain a polymer of formula I:

[0014]

[0015] In formula II-III, R1 and Ar are defined the same as in formula I.

[0016] In the above preparation method, the gas of the inert atmosphere is nitrogen or argon.

[0017] In the above preparation method, the catalyst is methanesulfonic acid (tri-tert-butylphosphino)(2'-methylamino-1,1'-biphenyl-2-yl) palladium (II) (abbreviated as Pd-P(t-Bu)3-G4), and trimethylsilanol potassium (abbreviated as TMSOK) is used as the alkaline substance.

[0018] In the above preparation method, the molar ratio of the compound represented by formula II, the compound represented by formula III, the catalyst and the alkaline substance is 1:1:0.05:2.2.

[0019] The temperature of the carbon-carbon coupling reaction is 35° C. and the reaction time is 72 hours.

[0020] The organic solvent for the carbon-carbon coupling reaction is anhydrous toluene.

[0021] Furthermore, the preparation steps of the compound represented by formula II include:

[0022] Under an inert atmosphere, the compound represented by Formula IV and diphenylphosphoryl azide (DPPA for short) are subjected to a nucleophilic aromatic substitution reaction under the action of 1,8-diazobispiro[5.4.0]undec-7-ene (DBU for short) to convert the hydroxyl group on the benzyl alcohol into an azide group to obtain a compound represented by Formula II:

[0023]

[0024] In the method for preparing the compound of formula II, the molar ratio of the compound represented by formula IV to the N3 group in diphenylphosphoryl azide is 1:2 to 10;

[0025] The reaction temperature is 45°C and the reaction time is 24 to 36 hours;

[0026] The reaction solvent is tetrahydrofuran;

[0027] The inert atmosphere gas is nitrogen or argon.

[0028] Thirdly, the present invention provides the application of the polymer shown in Formula I in at least one of the following (1) to (4): (1) being soluble in an organic solvent and processed into a uniform light-emitting film by solution processing; (2) itself being used as a polymer semiconductor type photoresist and patterned by a direct lithography process; (3) being used as a general crosslinking agent in the lithographic patterning of organic semiconductors; (4) being used in the preparation of organic optoelectronic devices.

[0029] Compared with the prior art, the beneficial technical effects brought by the technical solution of the present invention application are:

[0030] 1. The raw materials used in the synthesis of the present invention are convenient to obtain. Compared with the method of synthesizing an azide group using sodium azide, the synthesis process is safer and is easy to industrialize and produce on a large scale;

[0031] 2. The polymer of the present invention has excellent solution processing characteristics, good film-forming property and relatively high luminous efficiency;

[0032] 3. The polymer of the present invention can realize the patterning of an organic semiconductor film through a direct lithography process, and the process is simple, greatly simplifying the preparation steps of organic integrated optoelectronic devices;

[0033] 4. The polymer of the present invention can undergo a crosslinking reaction with other polymers containing long alkyl chains and can be used as a crosslinking agent for the crosslinking and curing of polymer films. Description of the Drawings

[0034] Figure 1 It is the 1 1H-NMR spectrum of Compound IV in Example 1 of the present invention;

[0035] Figure 2 It is the 13 13C-NMR spectrum of Compound IV in Example 1 of the present invention;

[0036] Figure 3 It is the 1 1H-NMR spectrum of Compound II in Example 1 of the present invention;

[0037] Figure 4 It is the 13 13C-NMR spectrum of Compound II in Example 1 of the present invention;

[0038] Figure 5 It is the 1 1H-NMR spectrum of the polymer shown in Formula I in Example 2 of the present invention;

[0039] Figure 6For the polymer shown in Formula I in Embodiment 3 of the present invention 1 1H-NMR spectrum;

[0040] Figure 7 Direct lithographic patterning of the polymer PFO-alt-AzDPF thin film in Embodiment 4 of the present invention;

[0041] Figure 8 Spectral properties of the toluene solution and thin film of the polymer PFO-alt-AzDPF in Embodiment 4 of the present invention;

[0042] Figure 9 Spectral properties of the toluene solution and thin film of the polymer FAzBT in Embodiment 5 of the present invention;

[0043] Figure 10 Schematic structural diagram of the polymer electroluminescent device in Embodiment 6 of the present invention;

[0044] Figure 11 Performance curve graph of the polymer electroluminescent device in Embodiment 6 of the present invention. Detailed implementation manners

[0045] The present invention will be further described below in conjunction with specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0046] It should be noted that unless otherwise specified, the technical terms or scientific terms used in this application should be the ordinary meanings understood by those skilled in the art to which the present invention belongs. The raw materials, reagents, etc., unless otherwise specified, can all be obtained from public commercial channels.

[0047] Embodiment 1

[0048] Synthesis of the compound of Formula II (wherein, R1 is hexyl):

[0049]

[0050] 1. Synthesis of the compound of Formula IV (in Formula IV, R1 is hexyl), and the specific synthesis route is as follows:

[0051]

[0052] The specific reaction step conditions are as follows:

[0053] (1) Synthetic product Br-PhMeOH: Dissolve p-hydroxybenzyl alcohol (8.10 mmol) and 1,6-dibromohexane (12.15 mmol) in 10 mL of acetone, then add potassium carbonate (16.64 mmol) and react at room temperature for 48 h. After the reaction is completed, perform multiple liquid-liquid extractions with dichloromethane and water. Then, obtain the product Br-PhMeOH through steps such as vacuum distillation, silica gel column chromatography, and drying.

[0054] (2) Synthesis of DBFOH: Dissolve 2,7-dibromo-9-fluorenone (17.75 mmol) and phenol (30.70 mmol) in 45 mL of methanesulfonic acid (MeSO3) and react at a reaction temperature of 50 °C for 12 h. After the reaction is completed, quench the reaction with 10 mL of saturated sodium chloride aqueous solution, and then perform liquid-liquid extraction with dichloromethane. Then, obtain the product DBFOH (15.74 mmol, yield 88.7%) after vacuum distillation, silica gel column chromatography, and drying of the organic phase.

[0055] (3) Dissolve compound Br-PhMeOH (1.97 mmol) and DBFOH (9.85 mmol) in 10 mL of acetone, then add potassium carbonate (7.23 mmol) and react at 90 °C for 48 h. After the reaction is complete, add 10 mL of water to quench the reaction, and then perform liquid-liquid extraction with dichloromethane. Then, obtain compound IV (1.09 mmol, yield 55.3%) after vacuum distillation, silica gel column chromatography, and drying of the organic phase. The structure confirmation data are as Figure 1 and Figure 2 shown: 1 1H-NMR (400 MHz, CDCl3) δ 7.56 (d, 2H), 7.45 (dd, 4H), 7.27 (s, 2H), 7.26 (d, 2H), 7.03 (d, 4H), 6.86 (d, 4H), 6.75 (d, 4H), 4.60 (s, 4H), 3.93 (dt, 8H), 1.78 (d, 8H), 1.50 (d, 8H); 13 13C-NMR (101 MHz) δ 158.81, 158.24, 153.79, 137.94, 136.42, 133.02, 130.84, 129.34, 129.10, 128.75, 121.88, 121.65, 114.63, 114.42, 67.89, 65.20, 64.42, 63.00, 29.27, 25.97.

[0056] 2. Synthesis of the compound of formula II, and the specific synthesis route is as follows:

[0057]

[0058] The specific reaction step conditions are as follows:

[0059] Dissolve compound IV (1.09 mmol) in 10 mL of tetrahydrofuran, then add compound DBU (5.26 mmol), and slowly add DPPA (4.90 mmol). React under nitrogen atmosphere in the dark at a reaction temperature of 45 °C for 36 hours. After the reaction is completed, first add 1 mL of saturated sodium bicarbonate solution to quench the reaction, and then perform multiple extractions with water and dichloromethane. After that, the organic phase is obtained by distillation under reduced pressure, silica gel column chromatography, and drying to obtain compound II (0.88 mmol, yield: 80.3%). The structure confirmation data is as Figure 3 and Figure 4 shown below: 1 H-NMR (400 MHz, CDCl3) δ 7.57 (d, 2H), 7.46 (s, 4H), 7.35 (s, 2H), 7.22 (d, 6H), 7.04 (d, 4H), 6.89 (d, 4H), 6.76 (d, 4H), 4.25 (s, 4H), 3.94 (d, 8H), 1.81 (s, 8H), 1.52 (s, 8H); 13 C-NMR (101 MHz) δ 159.23, 158.25, 153.80, 137.95, 136.43, 129.91, 129.35, 129.11, 127.27, 125.72, 121.89, 121.66, 120.23, 114.82, 114.43, 67.89, 64.45, 54.51, 29.26, 25.94.

[0060] Example 2

[0061] Synthesis of the polymer of formula I (in formula I, R1 is hexyl and Ar is 9,9-dioctylfluorene), and the polymer is named PFO-alt-AzDPF:

[0062]

[0063] The synthesis route is as follows:

[0064]

[0065] Compound II (0.20 mmol) and 9,9-dioctylfluorene-2,7-diboronic acid dipinacol ester (0.20 mmol) were added to a 10 mL Shrek tube, and then the catalysts methanesulfonic acid (tri-tert-butylphosphino) (2'-methylamino-1,1'-biphenyl-2-yl) palladium (II) (Pd-P(t-Bu)3-G4, 0.01 mmol) and trimethylsilanol potassium (TMSOK, 0.44 mmol) were added, and after nitrogen was pumped three times, 2 mL of anhydrous toluene was added, and the reaction was allowed to react at a temperature of 35 ° C and a nitrogen atmosphere for 72 hours. After that, 0.5 mL of bromobenzene and 0.5 mL of phenyl borate were added to the reaction solution for end-capping, and the reaction was carried out for 6 hours respectively. After the reaction was completed, the reaction solution was dripped into 100 mL of methanol for precipitation, and a solid product was obtained by suction filtration. The obtained solid was extracted by Soxhlet extraction with acetone and n-hexane to remove unreacted raw materials and oligomers, and finally the target product was extracted with chloroform. Finally, the chloroform solution containing the target product was concentrated by vacuum distillation, and then precipitated with methanol again. The final target polymer PFO-alt-AzDPF was obtained by suction filtration and drying. The relative molecular weight (M) of the polymer was obtained by GPC test. n ) is 1.5 kDa. The structural confirmation data are as follows Figure 5 As shown: 1 H-NMR(400MHz, CDCl3)δ7.88(d,2H),7.77-7.71(m,2H),7.70(s,4H),7.54(s,4H),7.29(d,4H),7.21(d,4H),6.88(d,4H) ,6.82(d,4H),4.24(s,4H),3.95(t,8H),1.80(s,8H),1.52(s,8H),1.40(s,2H),1.26(s,2H),1.13(d,24H),0.78(d,8H).

[0066] Embodiment 3:

[0067] Synthesis of a polymer of formula I (wherein R1 is hexyl and Ar is 2,1,3-benzothiadiazole), the polymer is named FAzBT:

[0068]

[0069] The synthetic route is as follows:

[0070]

[0071] Compound II (0.4mmol) and 4,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2,1,3-benzothiadiazole (0.4mmol) were added to a 10mL Shrek tube. Then, the catalysts methanesulfonic acid (tri-tert-butylphosphino) (2'-methylamino-1,1'-biphenyl-2-yl) palladium (II) (0.02mmol) and trimethylsilanol potassium (0.88mmol) were added respectively, and after nitrogen was pumped 3 times, 2mL of anhydrous toluene was added, and the reaction was allowed to react at a temperature of 35°C and a nitrogen atmosphere for 72 hours. 0.5mL of bromobenzene and 0.5mL of phenylboronic acid ester were added to the reaction solution for end-capping, and the reaction was carried out for 6 hours respectively. After the reaction was completed, the reaction solution was dripped into 100mL of methanol for precipitation, and a solid product was obtained by suction filtration. The solid product was dissolved in dichloromethane, poured into a neutral alumina column for chromatography, and then distilled under reduced pressure, concentrated and dried to obtain a polymer. Finally, the product FAZBT was extracted by Soxhlet extraction with acetone to remove unreacted raw materials and oligomers, and the target product FAZBT was extracted. The polymer NMR was as follows: Figure 6 As shown: 1 H-NMR(400MHz, CDCl3)δ8.08(d,2H),7.99(s,4H),7.72(s,2H),7.30(d,4H),7.18(d,4H), 6.85(d,4H),6.78(d,4H),4.21(s,4H),3.92(t,8H),1.75-1.77(m,8H),1.51-1.45(m,8H).

[0072] Example 4

[0073] A photolithographic patterned light-emitting film is prepared based on the polymer represented by formula I of the present invention:

[0074] The polymer PFO-alt-AzDPF prepared in Example 2 of the present invention was dissolved in a toluene solution at a concentration of 8 to 10 mg / mL. Then, the solution was evenly spin-coated on a pre-cleaned glass sheet using a spin coater at a speed of 1500 rpm to obtain a uniform film with a thickness of about 35 to 40 nm. After that, a mask with a hollow pattern was covered on the film and irradiated with a 365 nm ultraviolet LED lamp for 2 to 10 seconds with a light power of about 20 mW / cm 2 At this time, the exposed part of the film will be cross-linked. Finally, the exposed film is soaked in chlorobenzene for 5 seconds, fully developed, taken out, rinsed with deionized water and blown dry with nitrogen, and the patterned preparation of a square dot matrix of 40×40μm can be achieved. The specific patterning example is Figure 7 As shown. Combined Figure 8 From the spectra shown, it can be found that the absorption and emission peak positions of the polymer film remain almost unchanged before and after photolithography.

[0075] Example 5

[0076] Prepare a lithographically patterned light-emitting thin film based on the polymer shown in Formula I of the present invention:

[0077] Dissolve the polymer FAzBT prepared in Example 3 of the present invention in a toluene solution with a concentration of 8-10 mg / mL. Then, spin-coat the solution evenly on a pre-cleaned glass slide at a rotation speed of 1500 rpm to obtain a uniform thin film with a thickness of about 35-40 nm. After that, cover a mask plate with a hollow pattern on the thin film and irradiate it with a 365-nm ultraviolet LED lamp for 2-10 seconds, with a light power of about 20 mW / cm 2 . At this time, the exposed part of the thin film will crosslink. Finally, soak the exposed thin film in chlorobenzene and rinse for 5 seconds, develop it fully, take it out, rinse it with deionized water, and dry it with nitrogen to achieve the patterned preparation of a 40×40 μm square dot matrix. Combining Figure 9 with the spectra shown, it can be found that the absorption and emission peak positions of the polymer thin film remain almost unchanged before and after lithography.

[0078] Example 6:

[0079] Application of the polymer PFO-alt-AzDPF in Example 2 of the present invention as a crosslinking agent in a polymer light-emitting diode:

[0080] On a cleaned indium tin oxide (ITO) glass substrate, first spin-coat a layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT:PSS) as a hole injection layer with a thickness of about 40 nm and anneal it at 120 °C in air for 20 min. Then, use the polymer PFO-alt-AzDPF prepared in Example 2 of the present invention as a crosslinking agent and mix it with the blue-light polymer poly[4-octyloxy-(9,9-diphenylfluorene)] (PODPF) in a mass ratio of 1:9 to form a toluene solution with a concentration of 10 mg / mL. Spin-coat it evenly on the PEDOT:PSS layer as a light-emitting layer with a thickness of about 40-50 nm and transfer it to a glove box for annealing treatment (120 °C, 15 min). After that, transfer the treated wafer to a vacuum evaporation chamber and sequentially evaporate 20 nm of 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) and 0.8 nm of lithium fluoride (LiF) as an electron transport and injection layer, respectively. Finally, evaporate 100 nm of aluminum (Al) as the cathode, and the resulting device structure is as Figure 10 shown. The device performance curve is as Figure 11 shown. The turn-on voltage of the device is 4.6 V, and the maximum emission brightness is 670 cdm -2, the maximum external quantum efficiency (EQE) is 0.65%, and the emission peak of the electroluminescence spectrum is 480 nm, demonstrating the potential application value of this polymer as a crosslinking agent in the field of polymer electroluminescence.

[0081] The present invention has been disclosed in the preferred embodiments, but it is not intended to limit the present invention. Any technical solutions obtained by adopting equivalent replacement or equivalent transformation are within the protection scope of the present invention.

Claims

1. A polymer, characterized in that, Its structural formula is shown in the following formula I: ； Formula I In the formula, Ar is selected from an aromatic ring, a heteroaromatic ring, an aromatic ring or a heteroaromatic ring containing a long alkyl chain substituent; R1 is selected from one of the alkyl chains containing methylene in C1-C50; The number average molecular weight of the polymer represented by formula I is 10,000-100,000.

2. The polymer according to claim 1, wherein Ar is selected from any one of the following structural formulas: ； In the formula, R is selected from any one of the alkyl chains containing methylene in C1-C50; Represents the bonding position in Structural Formula I.

3. The method for preparing the polymer according to claim 1, wherein, include: In the presence of an inert atmosphere and a catalyst, the compound represented by Formula II and the compound represented by Formula III are subjected to a carbon-carbon coupling reaction in an organic solvent to obtain a polymer represented by Formula I: ； Formula II ； Formula III In formula II-III, Ar is selected from an aromatic ring, a heteroaromatic ring, an aromatic ring or a heteroaromatic ring containing a long alkyl chain substituent; and R1 is selected from one of the C1-C50 alkyl chains containing a methylene group.

4. The method for preparing the polymer according to claim 3, wherein The catalyst is methanesulfonic acid (tri-tert-butylphosphino)(2'-methylamino-1,1'-biphenyl-2-yl)palladium(II), and potassium trimethylsilanol is used as the alkaline substance.

5. The preparation method of the polymer according to claim 4, characterized in that, The molar ratio of the compound represented by formula II, the compound represented by formula III, the catalyst and the alkaline substance is 1:1:0.05:2.

2.

6. The method for preparing the polymer according to claim 3, wherein, The temperature of the carbon-carbon coupling reaction was 35° C. and the reaction time was 72 hours.

7. The method for preparing the polymer according to claim 3, characterized in that, The organic solvent for the carbon-carbon coupling reaction is anhydrous toluene.

8. The method for preparing the polymer according to claim 3, wherein The preparation steps of the compound shown in formula II include: Under an inert atmosphere, the compound represented by formula IV and diphenylphosphoryl azide are subjected to a nucleophilic aromatic substitution reaction under the action of 1,8-diazobispiro[5.4.0]undec-7-ene to convert the hydroxyl group on the benzyl alcohol into an azide group to obtain a compound represented by formula II: ； Formula IV.

9. The method for preparing the polymer according to claim 8, characterized in that, In the preparation steps of the compound represented by formula II, one or more of the following conditions are met: The molar ratio of the compound represented by formula IV to the N3 group in diphenylphosphoryl azide is 1:2-10; The reaction temperature is 45°C and the reaction time is 24 to 36 hours; The reaction solvent is tetrahydrofuran.

10. The use of the polymer according to claim 1, wherein the polymer is used in at least one of the following (1) to (4): (1) in the preparation of a light-emitting thin film; (2) as a polymer semiconductor photoresist itself, patterned by a direct photolithography process; (3) as a universal crosslinking agent in the photolithography patterning of organic semiconductors; (4) in the preparation of an organic optoelectronic device.

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