Conjugated polymer hole transport layer material containing triphenylamine and preparation method thereof

Abstract

The invention belongs to the technical field of solar cells, and particularly relates to a triphenylamine-containing conjugated polymer hole transport layer material and a preparation method thereof. The preparation method of the triphenylamine conjugated polymer comprises the following steps: reacting aniline with bromobenzene under the action of a catalyst to generate a compound 1; reacting the compound 1 with NBS (N-bromosuccinimide), and performing bromination reaction to obtain a compound 2; reacting the compound 2 under the action of bis-pinacol diboron, potassium acetate and a catalyst to obtain a compound 3; the method comprises the following steps: dissolving a monomer 1, a monomer 2 and a catalyst in an organic solvent, and carrying out polymerization reaction under the protection of nitrogen to obtain the triphenylamine conjugated polymer. The synthetic route is simple, the yield is high, conditions are easy to realize, and the hole transport layer material prepared from the conjugated polymer of triphenylamine is high in transport efficiency and can be popularized in a large range.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and particularly relates to a conjugated polymer hole transport layer material containing triphenylamine and a preparation method thereof. Background Art

[0002] In recent years, perovskite solar cells have made remarkable progress, and their photoelectric conversion efficiency has increased from 3.8% to the current 26.7% in less than a decade. One of the important components of perovskite solar cells is the hole transport layer, which selectively extracts holes from the perovskite layer and effectively transports the holes to the electrode. Although perovskite solar cells exhibit excellent performance, there are still problems such as stability and long-term reliability. Among them, the selection and optimization of the hole transport layer material are the key to improving perovskite solar cells.

[0003] However, the currently widely used hole transport layer materials are limited. The most popular hole transport layer materials are represented by poly(triarylamine) and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and the use of appropriate doping can provide higher efficiency. Some studies have shown that the molecular weight of the polymer hole transport layer has a significant impact on its transport performance and device efficiency. Therefore, how to control the molecular weight of the polymer through chemical reactions still needs to be further explored. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a conjugated polymer hole transport layer material containing triphenylamine and a preparation method thereof. The conjugated polymer of triphenylamine is the material of the transport layer. The present invention provides a preparation method of a conjugated polymer high molecular material of triphenylamine, and the efficiency of the transport layer is regulated by regulating the molecular weight of the polymer. The technical solution adopted is as follows:

[0005] A conjugated polymer hole transport layer material containing triphenylamine, including a triphenylamine-based conjugated polymer, and the molecular structure of the polymer is shown as follows:

[0006]

[0007] Among them, R, R 1 , R 2 are CH 3 , H, F or Cl, and n is the average degree of polymerization.

[0008] A preparation method of a conjugated polymer hole transport layer material containing triphenylamine, that is, a preparation method of a triphenylamine-based conjugated polymer includes the following steps:

[0009] (i) First, aniline and bromobenzene are reacted under the action of a catalyst to generate Compound 1, and the chemical equation is:

[0010]

[0011] (ii) Compound 1 reacts with NBS and then undergoes bromination to obtain compound 2, the formula of which is:

[0012]

[0013] (iii) Compound 2 is reacted with bispinacol diboron, potassium acetate and a catalyst to obtain compound 3, the formula is:

[0014]

[0015] (iv) Monomer 1 and monomer 2 are dissolved in an organic solvent with a catalyst, and a polymerization reaction is carried out under nitrogen protection to obtain a triphenylamine-based conjugated polymer, the formula of which is:

[0016]

[0017] Preferably, the catalyst in step (i) is palladium acetate, and the ligand is tri-tert-butylphosphine. Compound 1 can be obtained by stirring and refluxing in toluene while introducing nitrogen atmosphere.

[0018] Preferably, the bromination reagent used in step (ii) is NBS, the reaction solvent is chloroform, and the reaction is carried out at room temperature.

[0019] Preferably, in step (iii), diboron bispinacol and potassium acetate are added to the 1,4-dioxane solution of compound 2 to obtain Pd(dppf)Cl 2 The catalyst is dichloro[1,1'-bis(diphenylphosphino)ferrocene]palladium.

[0020] Preferably, the reaction temperature is 101° C., the boiling point of the solvent 1,4-dioxane is 101° C., and the reaction is carried out at the boiling point of the solvent.

[0021] Preferably, in step (iv), monomer 1 is compound 2 prepared in step (ii), monomer 2 is compound 3 prepared in step (iii), and the molar ratio of monomer 1 to monomer 2 is 1:1.

[0022] Preferably, the catalyst for the polymerization of monomer 1 and monomer 1 is Ni(COD) 2 The solvent used was tetrahydrofuran and the reaction temperature was 80°C.

[0023] Preferably, the preferred catalyst for the polymerization of the two compounds of Monomer 1 and Monomer 2 is tetrakistriphenylphosphine palladium, and the solvent used in the reaction is tetrahydrofuran.

[0024] Preferably, the reaction temperature is 110°C.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The hole transport layer material prepared by the conjugated polymer of triphenylamine of the present invention has high transport efficiency and is one of the important components for preparing organic solar cells.

[0027] The present invention optimizes the synthesis route of the conjugated polymer of triphenylamine and provides a method for preparing conjugated polymers of triphenylamine with different molecular weights.

[0028] The synthesis route of the present invention is simple, has a high yield, and the conditions are easy to achieve, and can be widely promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a route diagram for synthesizing the conjugated polymer of triphenylamine of the present invention.

[0030] Figure 2 It is a 1H NMR spectrum of Compound 1 synthesized by the present invention.

[0031] Figure 3 It is a 1H NMR spectrum of Compound 2 synthesized by the present invention.

[0032] Figure 4 It is a 1H NMR spectrum of Compound 3 synthesized by the present invention.

[0033] Figure 5 It is a GPC integral curve of PTAA prepared in Example 1 by Yamamoto coupling of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The drawings are only for illustrative purposes. The technical solutions of the present invention will be described in detail below with reference to the drawings and embodiments. Unless otherwise specified, the chemical substances, instruments, etc. used in the present invention can be obtained through conventional commercial channels.

[0035] As Figure 1 shown, the preparation method of the hole transport layer material of the conjugated polymer containing triphenylamine, that is, the preparation method of the triphenylamine-based conjugated polymer includes the following steps.

[0036] Synthesis of Compound 1:

[0037] In N 2Under the atmosphere, mesitylidine (10 g, 1 eq), bromobenzene (23.23 g, 2 eq) were added to toluene (300 mL), potassium tert-butoxide (16.6 g, 2 eq) was added in portions, tri-tert-butylphosphine (0.3 g, 0.02 eq) and palladium acetate (0.17 g, 0.01 eq) were added, and the mixture was refluxed and stirred overnight. After the reaction solution was cooled to room temperature, it was extracted with water / dichloromethane 3 times to obtain an organic phase, which was dried over anhydrous magnesium sulfate and the solvent was removed in vacuo to obtain a crude product, which was then chromatographed on a silica gel column to obtain the target product with a yield of 90%.

[0038] like Figure 2 As shown, 1 H NMR (600MHz, Chloroform-d) δ7.25 (d, J = 1.9 Hz), 7.18 (td, J = 7.2, 3.6 Hz), 7.06–6.92 (m), 6.91–6.79 (m), 2.32 (d, J = 2.1 Hz), 1.99 (d, J = 2.3 Hz), 0.00.

[0039] Synthesis of compound 2:

[0040] 2,4,6-trimethyltriphenylamine (5g, 1eq) was dissolved in chloroform (100mL), and NBS (6.5g, 2.1eq) was added in batches under ice bath, and stirred overnight in the dark. The reaction solution was extracted with water / dichloromethane for 3 times to obtain an organic phase, which was dried over anhydrous magnesium sulfate and the solvent was removed in vacuo to obtain a crude product, which was then chromatographed on a silica gel column to obtain the target product with a yield of 98%.

[0041] like Figure 3 As shown, 1 H NMR (500 MHz, Chloroform-d) δ7.28 (dd, J = 10.1, 2.0 Hz, 2H), 6.94 (s, 1H), 6.86–6.79 (m, 2H), 2.32 (d, J = 2.4 Hz, 2H), 1.97 (d, J = 2.5 Hz, 3H).

[0042] Synthesis of compound 3:

[0043] In N 2 Under a 300 mL atmosphere, N,N'-bis(4-bromophenyl)-2,4,6-trimethylaniline (7 g, 1 eq), potassium acetate (4.62 g, 3 eq), bis(pinacol)diboron (8.79 g, 2.2 eq) were added to 1,4-dioxane (300 mL). 2(0.35 g, 0.03 eq), reflux and stir overnight. After the reaction solution was cooled to room temperature, it was extracted 3 times with water / dichloromethane to obtain the organic phase, dried over anhydrous magnesium sulfate, the solvent was removed under vacuum to obtain the crude product, and the target product was obtained by silica gel column chromatography with a yield of 91%.

[0044] As Figure 4 shown, 1 1H NMR (600 MHz, Chloroform-d) δ 7.67–7.57 (m), 7.25, 6.98–6.87 (m), 3.48, 2.31, 1.94, 1.38 (d, J = 38.1 Hz), 1.31.

[0045] Synthesis of PTAA:

[0046] Yamamoto coupling of PTAA: Weigh N,N'-bis(4-bromophenyl)-2,4,6-trimethylaniline (1 eq), Ni(COD) 2 (1.25 eq) and the catalyst ligand (1.25 eq) in the glove box and add them to the reaction flask, seal it and take it out. Inject 1,5-cyclooctadiene (1.25 eq) and the solvent into the above different reaction flasks with a syringe, and stir at 80 °C for 16 h under airtight conditions. After cooling to room temperature, precipitate the product into methanol solvent and stir for 5 min. The obtained polymer was successively purified by Soxhlet extraction with methanol, acetone, ethyl acetate, and dichloromethane. The dichloromethane fraction was collected, the solvent was removed under vacuum, and then precipitated with methanol. The precipitate was filtered out, dried, weighed, and the yield was calculated.

[0047] (1) Using different reaction solvents as the solvent, the yield information of the prepared polymers is shown in Table 1.

[0048] Table 1 Yield information of polymers prepared with different reaction solvents

[0049]

[0050]

[0051] When the solvent used was THF (tetrahydrofuran), the yield was the highest.

[0052] (2) Using different catalyst ligands as the catalyst for the reaction, the yield of the prepared polymers is shown in Table 2.

[0053] Table 2 Yield information of polymers prepared with different catalyst ligands

[0054]

[0055] In Group 5, Ni(COD) was used 2Using +COD + bipy as the catalyst, the yield is 84%. Since the yield of PTAA prepared using dioxane, toluene, and DMF (dimethylformamide) as reaction solvents is low, it indicates that the polymerization reactions of the other groups did not occur successfully, and no molecular weight information was obtained. The molecular weight information of the polymer using THF as the solvent is as follows:

[0056] Mn: 7.31 kDa; M W : 12.69 kDa; PDI: 1.74.

[0057] The molecular weight integral curve is as shown in Figure 5 the figure.

[0058] Suzuki coupling of PTAA: Weigh two monomers, a base, and a catalyst separately. First, add the two monomers, the base, and the phase transfer catalyst to a round-bottom flask, then add the solvent, stir with a magnetic stirrer, and at the same time perform degassing. Add the catalyst under an N 2 atmosphere, re-degas, and then heat to reflux for three days. After three days of reaction, cool the reaction solution to room temperature, remove the solvent, precipitate the resulting polymer in methanol, perform Soxhlet extraction with methanol, acetone, and chloroform respectively, collect the chloroform fraction, remove the solvent under vacuum and then precipitate with methanol, filter out the precipitate, dry it, weigh the weight, calculate the yield, and test the molecular weight, as shown in Table 3.

[0059] Table 3 Molecular weight and yield information of polymers prepared under different solvents

[0060]

[0061] When the solvent is THF / H 2 O, the yield of the polymer is the highest.

[0062] The molecular weight and yield information of polymers prepared under different base conditions are shown in Table 4.

[0063] Table 4 Molecular weight and yield information of polymers prepared under different base conditions

[0064]

[0065] When the base solution is K 2 CO 3 3, the yield of the polymer is the highest.

[0066] The molecular weight and yield information of polymers prepared under different catalyst systems are shown in Table 5.

[0067] Table 5 Molecular weight and yield information of polymers prepared under different catalytic systems

[0068]

[0069] The polymer yield is the highest when the catalyst is Pd(PPh 3 ) 4 .

[0070] The Chinese names of the English abbreviations used in the present invention are as follows:

[0071] Ni(COD) 2 : bis(1,5-cyclooctadiene)nickel;

[0072] COD: 1,5-cyclooctadiene;

[0073] Bipy: 2,2'-bipyridine;

[0074] Pph3: triphenylphosphine;

[0075] Dppf: 1,1'-bis(diphenylphosphino)ferrocene;

[0076] Dppe: 1,2-bis(diphenylphosphino)ethane;

[0077] Xantphos: 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene.

[0078] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the essence of the present invention shall also fall within the protection scope of the present invention.

Claims

1. A conjugated polymer hole transport layer material containing triphenylamine, characterized in that: Including triphenylamine-based conjugated polymers, the molecular structure of the polymer is shown below: Wherein, R, R1, R2 are CH3, H, F or Cl, and n is the average degree of polymerization.

2. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 1, characterized in that: The preparation method of triphenylamine-based conjugated polymer comprises the following steps: (i) First, aniline and bromobenzene are reacted in the presence of a catalyst to generate compound 1, the formula being: (ii) Compound 1 reacts with NBS and then undergoes bromination to obtain compound 2, the formula of which is: (iii) Compound 2 is reacted with bispinacol diboron, potassium acetate and a catalyst to obtain compound 3, the formula is: (iv) Monomer 1 and monomer 2 are dissolved in an organic solvent with a catalyst, and a polymerization reaction is carried out under nitrogen protection to obtain a triphenylamine-based conjugated polymer, the formula of which is:

3. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 2, characterized in that: The catalyst in step (i) is palladium acetate, and the ligand is tri-tert-butylphosphine. Compound 1 can be obtained by stirring and refluxing in toluene while introducing nitrogen atmosphere.

4. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 2, characterized in that: The bromination reagent used in step (ii) is NBS, the reaction solvent is chloroform, and the reaction is carried out at room temperature.

5. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 2, characterized in that: Step (iii) Add bis(pinacol)diboron, potassium acetate and Pd(dppf)Cl2 as a catalyst to a 1,4-dioxane solution of compound 2.

6. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 5, characterized in that: The reaction temperature was 101°C.

7. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 2, characterized in that: In step (iv), monomer 1 is compound 2 prepared in step (ii), monomer 2 is compound 3 prepared in step (iii), and the molar ratio of monomer 1 to monomer 2 is 1:

1.

8. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 7, characterized in that: The catalyst for the polymerization of monomer 1 with monomer 1 is Ni(COD)2, the solvent used is tetrahydrofuran, and the reaction temperature is 80°C.

9. The method for preparing the triphenylamine-containing conjugated polymer hole transport layer material according to claim 8, characterized in that: The catalyst for the polymerization of the two compounds, monomer 1 and monomer 2, is tetrakistriphenylphosphine palladium, and the solvent used in the reaction is tetrahydrofuran.

10. The method for preparing a triphenylamine-containing conjugated polymer hole transport layer material according to claim 9, characterized in that: The reaction temperature is 40-110°C.

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