A non-fullerene organic solar cell polymer donor and a preparation method and application thereof

Abstract

The application belongs to the technical field of polymer solar cells, and particularly relates to a non-fullerene organic solar cell polymer donor, a preparation method and application thereof. The donor material has a structure shown in formula (I-1) or formula (I-2). Based on the morphology characteristics of the non-fullerene acceptor material, the alkyl chain and conjugated structure of the donor material blended with the non-fullerene acceptor material are modulated, so that the donor material obtains ideal crystallinity, and meanwhile, the miscibility of the donor material with the non-fullerene acceptor material is enhanced, the self-aggregation of the donor and acceptor materials is inhibited, and the formation of a large phase size of the active layer is avoided. Finally, the blended layer of the donor material and the non-fullerene acceptor material can form a nano-interpenetrating network structure with a suitable size, the dissociation efficiency of the carriers is improved, the two-molecule recombination is reduced, the morphology of the active layer of the polymer solar cell can be improved, and the photoelectric conversion efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer solar cell technology, specifically relating to a polymer donor for a non-fullerene organic solar cell, its preparation method, and its application. Background Technology

[0002] Polymer solar cells are a new type of photovoltaic device that achieves photoelectric conversion based on organic polymer light-absorbing materials. They have received widespread attention and are gradually being industrialized due to their advantages such as tunable molecular structure, low cost, lightweight and portable design, and the ability to quickly process flexible devices on a large scale using roll-to-roll and spray printing technologies.

[0003] The active layer of a polymer solar cell, composed of donor and acceptor materials, is the core site for absorbing sunlight and achieving photoelectric conversion. Designing and synthesizing novel donor and acceptor materials to achieve the desired morphology of the active layer is key to improving the photoelectric conversion efficiency of polymer solar cells. Early polymer solar cells were mostly based on fullerene systems, with fullerenes or fullerene derivatives, such as PC, as their acceptor materials. 61 BM, PC 71 While fullerenes have been used in various fields, such as BM and ICBA, their narrow absorption spectral range limits the improvement of photoelectric conversion efficiency in polymer solar cells based on fullerene systems. Currently, non-fullerene acceptors, primarily Y6 and its derivatives, are commonly used as acceptor materials. Fullerenes are typically hollow spherical structures, while non-fullerene acceptors are often fused-ring molecules with large conjugated planes, exhibiting completely different morphological characteristics. Therefore, it is difficult for donor materials designed based on traditional fullerene acceptors to achieve ideal morphologies with non-fullerene acceptors, resulting in lower photoelectric conversion efficiency. Currently, numerous donor materials have been designed for non-fullerene acceptors, but problems remain regarding the crystallinity of the donor materials themselves and their poor miscibility with acceptor materials. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned technical problems of donor materials used for non-fullerene acceptor materials, thereby providing a polymer donor for non-fullerene organic solar cells, its preparation method and application.

[0005] Therefore, the present invention provides the following technical solution:

[0006] This invention provides a polymer donor for a non-fullerene organic solar cell, the polymer donor having a structure as shown in formula (I-1) or (I-2):

[0007]

[0008] Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, R3 is 2-methylpropyl, and n is a natural number between 5 and 100.

[0009] The present invention also provides a method for preparing the polymer donor of the above-mentioned non-fullerene organic solar cell, characterized in that it is obtained by polymerization of compound 6 or compound 12 and compound 7 as shown below via a Stille reaction.

[0010]

[0011] Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, and R3 is 2-methylpropyl.

[0012] Optionally, the Stieler reaction is carried out at a temperature of 100°C to 110°C and for a reaction time of 4 hours to 24 hours.

[0013] Optionally, the Stieler reaction is carried out under the catalysis of a palladium catalyst.

[0014] Alternatively, the synthetic route for the compound shown in formula (I-1) is as follows:

[0015]

[0016] And / or, the synthetic route for the compound shown in formula (I-2) is as follows:

[0017]

[0018] Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, and R3 is 2-methylpropyl.

[0019] In this invention, the reaction conditions for each step in the synthetic route of the compound shown in formula (I-1) or formula (I-2) are all conventional in the field.

[0020] The present invention also provides the application of the polymer donor of the above-mentioned non-fullerene organic solar cell or the polymer donor of the non-fullerene organic solar cell prepared by the above-mentioned preparation method in organic solar cells.

[0021] The present invention also provides an organic solar cell, wherein the active layer includes a donor material and an acceptor material, wherein the donor material is the polymer donor described above or a polymer donor prepared by the above preparation method, and the acceptor material is a non-fullerene acceptor material.

[0022] Optionally, the mass ratio of the donor material to the acceptor material is 1:(1.0 to 1.2).

[0023] The present invention also provides an electrical device comprising the above-described organic solar cell.

[0024] Specifically, the synthetic steps of the compound shown in formula (I-1) include:

[0025] (1) Synthesis of compound 2: Under an inert atmosphere, n-butyllithium was added to the solution of compound 1. After the reaction was complete, 1-bromo-2-butyloctane was added. After the reaction was completed, the solvent was removed from the reaction solution and the solution was purified to obtain compound 2.

[0026] (2) Synthesis of compound 3: Under an inert atmosphere, n-butyllithium was added to the solution of compound 2. After the reaction was complete, bromoisobutane was added. After the reaction was completed, the solvent was removed and the solution was purified to obtain compound 3.

[0027] (3) Synthesis of compound 4: Under an inert atmosphere, DMF and oxaloyl chloride were added to a solution of 2,5-dibromothiophene-3,4-dicarboxylic acid. After the reaction was complete, the solvent and DMF were removed. The product and compound 3 were dissolved in the solvent, and anhydrous aluminum chloride was added. After the reaction was completed, the reaction system was quenched, extracted, and purified to obtain compound 4.

[0028] (4) Synthesis of compound 5: Under an inert atmosphere, compound 4, 2-tributyltin thiophene, and tetratriphenylphosphine palladium were dissolved in anhydrous toluene and refluxed. After the reaction was completed, the solvent was removed and the mixture was purified to obtain compound 5.

[0029] (5) Synthesis of compound 6: Under an inert atmosphere, a solution of N-bromosuccinimide was added to a solution of compound 5. After the reaction was completed, the solvent was removed and the mixture was purified to obtain compound 6.

[0030] (6) Synthesis of the polymer shown in formula (Ⅰ-1): Under an inert atmosphere, compound 6, compound 7, and tetratriphenylphosphine palladium were dissolved in a solvent and refluxed. After the reaction was completed, the solvent was removed, the product was purified, and dried to obtain the polymer shown in formula (Ⅰ-1).

[0031] The synthetic steps of the compound shown in formula (I-2) include:

[0032] (1) Synthesis of compound 8: Under an inert atmosphere, n-butyllithium was added to a tetrahydrofuran solution of compound 1. After the reaction was complete, bromoisooctane was added. After the reaction was completed, the solvent was removed and the mixture was purified to obtain compound 8.

[0033] (2) Synthesis of compound 9: Under an inert atmosphere, n-butyllithium was added to the solution of compound 8. After the reaction was complete, 1-bromo-2-butyloctane was added. After the reaction was completed, the solvent was removed and the solution was purified to obtain compound 9.

[0034] (3) Synthesis of compound 10: Under an inert atmosphere, DMF and oxaloyl chloride were added to a solution of 2,5-dibromothiophene-3,4-dicarboxylic acid. After the reaction was complete, the solvent and DMF were removed from the reaction solution. The product and compound 9 were dissolved in the solvent and anhydrous aluminum chloride was added. After the reaction was completed, the reaction system was quenched, extracted and purified to obtain compound 10.

[0035] (4) Synthesis of compound 11: Under an inert atmosphere, compound 10, 2-tributyltin thiophene, and tetra-triphenylphosphine palladium were dissolved in anhydrous toluene and refluxed. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 11.

[0036] (5) Synthesis of compound 12: Under an inert atmosphere, a solution of N-bromosuccinimide was added to a solution of compound 12. After the reaction was completed, the solvent was removed and the mixture was purified to obtain compound 12.

[0037] (6) Synthesis of the polymer shown in formula (Ⅰ-2): Under an inert atmosphere, compound 7, compound 12, and tetraphenylphosphine palladium were dissolved in a solvent and refluxed. After the reaction was completed, the solvent was removed from the reaction solution, purified, and dried to obtain the polymer shown in formula (Ⅰ-2).

[0038] In this invention, the other components and preparation methods of the non-fullerene organic solar cell are all conventional in the field.

[0039] The technical solution of this invention has the following advantages:

[0040] This invention provides a polymer donor for a non-fullerene organic solar cell, having the structure shown in formula (I-1) or formula (I-2). Based on the morphological characteristics of the non-fullerene acceptor material, this invention modulates the structure of the donor material blended with it, enabling the donor material to achieve ideal crystallinity while enhancing its miscibility with the non-fullerene acceptor material. This suppresses self-aggregation of the donor and acceptor materials, avoiding excessively large phase regions in the active layer. Ultimately, the blended layer of the donor material and the non-fullerene acceptor material can form a nano-interpenetrating network structure of suitable size, improving carrier dissociation efficiency, reducing bimolecular recombination, improving the morphology of the polymer solar cell active layer, and enhancing photoelectric conversion efficiency. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 It is the monomer compound 6 in Example 1 of this invention. 1 H NMR spectrum;

[0043] Figure 2 It is the monomer compound 12 in Example 2 of this invention. 1 H NMR spectrum;

[0044] Figure 3 The normalized ultraviolet absorption spectra of polymer donors of formula (Ⅰ-1) and formula (Ⅰ-2) provided by the present invention in chloroform solution are shown.

[0045] Figure 4 This is the electrochemical cyclic voltammetry curve of the polymer donor formula (Ⅰ-1) provided by the present invention;

[0046] Figure 5 This is the electrochemical cyclic voltammetry curve of the polymer donor formula (Ⅰ-2) provided by the present invention;

[0047] Figure 6 These are the current-voltage curves of polymer solar cells based on formula (Ⅰ-1): Y6 and formula (Ⅰ-2): Y6 provided by the present invention;

[0048] Figure 7 These are the external quantum efficiency curves of organic solar cells based on formula (I-1): Y6 and formula (I-2): Y6 provided by this invention;

[0049] Figure 8 The effective voltage-photocurrent density curves of polymer solar cells based on formula (I-1): Y6 and formula (I-2): Y6 provided by this invention are shown.

[0050] Figure 9 These are atomic force microscopy test images of the active layer films based on formula (Ⅰ-1): Y6 and formula (Ⅰ-2): Y6, respectively, provided by the present invention;

[0051] Figure 10 These are transmission electron microscope test images of the active layer films based on formula (Ⅰ-1): Y6 and formula (Ⅰ-2): Y6, respectively, provided by the present invention. Detailed Implementation

[0052] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0053] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0054] In a first aspect, the present invention provides a polymer donor for non-fullerene organic solar cells, having a polymer having the following general chemical formula (I1) or (I2):

[0055]

[0056] Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, R3 is 2-methylpropyl, and n is a natural number between 5 and 100.

[0057] In this scheme, the polymer serves as the donor material for non-fullerene organic solar cells. Based on the morphological characteristics of the non-fullerene acceptor material, the alkyl chain of the donor material blended with it is modulated, which not only achieves ideal crystallinity of the donor material but also enhances its miscibility with the non-fullerene acceptor material, suppresses the self-aggregation of the donor and acceptor materials, and avoids the formation of excessively large phase regions in the active layer. Ultimately, the blended layer of the donor material and the non-fullerene acceptor material can form a nano-interpenetrating network structure of suitable size, which improves the dissociation efficiency of charge carriers, reduces bimolecular recombination, thereby improving the morphology of the active layer of the polymer solar cell and enhancing the photoelectric conversion efficiency. The results show that the device based on formula (I-1): Y6 achieved a photoelectric conversion efficiency as high as 14.65%, and the device based on formula (I-2): Y6 achieved a photoelectric conversion efficiency as high as 15.68%.

[0058] Secondly, the present invention also provides a method for preparing the polymer donor shown in formula (Ⅰ-1), the process flow of which is as follows:

[0059]

[0060] The preparation method includes the following steps:

[0061] (1) Synthesis of compound 2: Under an inert atmosphere and at a reaction temperature of -78°C, n-butyllithium was added dropwise to an ultra-dry tetrahydrofuran solution of compound 1. Compound 1 is thiophene. After the reaction was complete, 1-bromo-2-butyloctane was added and the reaction was carried out at room temperature. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 2.

[0062] (2) Synthesis of compound 3: Under an inert atmosphere and at a reaction temperature of -78°C, n-butyllithium was added dropwise to an ultra-dry tetrahydrofuran solution of compound 2. After the reaction was complete, bromoisobutane was added and the reaction was carried out at room temperature. After the reaction was completed, the solvent was removed from the reaction solution and the solution was purified to obtain compound 3.

[0063] (3) Synthesis of compound 4: Under an inert atmosphere, a catalytic amount of DMF was added to an ultra-dry dichloromethane solution of 2,5-dibromothiophene-3,4-dicarboxylic acid, followed by the slow addition of oxaloyl chloride. After the reaction was complete at 50°C, the solvent and DMF were removed from the reaction solution. The product and compound 3 were dissolved in ultra-dry dichloromethane solvent, and anhydrous aluminum chloride was slowly added at 0°C. After the reaction was completed, the reaction system was slowly quenched in ice water, extracted to obtain the product, purified, and compound 4 was obtained.

[0064] (4) Synthesis of compound 5: Under an inert atmosphere, compound 4, 2-tributyltin thiophene, and a catalytic amount of tetratriphenylphosphine palladium were dissolved in anhydrous toluene and refluxed. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 5.

[0065] (5) Synthesis of compound 6: Under an inert atmosphere, a DMF solution of N-bromosuccinimide was added to a chloroform solution of compound 5 and reacted in the dark at room temperature. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 6.

[0066] (6) Synthesis of the polymer shown in formula (Ⅰ-1): Under an inert atmosphere, equimolar amounts of compound 6 and compound 7 and a catalytic amount of tetratriphenylphosphine palladium were dissolved in ultra-dry toluene and refluxed. After the reaction was completed, the solvent was removed from the reaction solution, purified, and dried to obtain the polymer shown in formula (Ⅰ-1).

[0067] Thirdly, the present invention also provides a method for preparing the polymer donor shown in formula (Ⅰ-2), the process flow of which is as follows:

[0068]

[0069] The preparation steps include:

[0070] (1) Synthesis of compound 8: Under an inert atmosphere and at a reaction temperature of -78°C, n-butyllithium was added dropwise to an ultra-dry tetrahydrofuran solution of compound 1. Compound 1 is thiophene. After the reaction was complete, bromoisooctane was added and the reaction was carried out at room temperature. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 8.

[0071] (2) Synthesis of compound 9: Under an inert atmosphere and at a reaction temperature of -78°C, n-butyllithium was added dropwise to an ultra-dry tetrahydrofuran solution of compound 8. After the reaction was complete, 1-bromo-2-butyloctane was added and the reaction was carried out at room temperature. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 9.

[0072] (3) Synthesis of compound 10: Under an inert atmosphere, a catalytic amount of DMF was added to an ultra-dry dichloromethane solution of 2,5-dibromothiophene-3,4-dicarboxylic acid, followed by the slow addition of oxaloyl chloride. After the reaction was complete at 50°C, the solvent and DMF were removed from the reaction solution. The product and compound 9 were dissolved in ultra-dry dichloromethane solvent, and anhydrous aluminum chloride was slowly added at 0°C. After the reaction was completed, the reaction system was slowly quenched in ice water, extracted to obtain the product, purified, and compound 10 was obtained.

[0073] (4) Synthesis of compound 11: Under an inert atmosphere, compound 10, 2-tributyltin thiophene, and a catalytic amount of tetratriphenylphosphine palladium were dissolved in anhydrous toluene and refluxed. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 11.

[0074] (5) Synthesis of compound 12: Under an inert atmosphere, a DMF solution of N-bromosuccinimide was added to a chloroform solution of compound 12 and reacted in the dark at room temperature. After the reaction was completed, the solvent was removed from the reaction solution and purified to obtain compound 12.

[0075] (6) Synthesis of the polymer shown in formula (Ⅰ-2): Under an inert atmosphere, equimolar amounts of compound 7 and compound 12 and a catalytic amount of tetraphenylphosphine palladium were dissolved in ultra-dry toluene and refluxed. After the reaction was completed, the solvent was removed from the reaction solution, purified, and dried to obtain the polymer shown in formula (Ⅰ-2).

[0076] Fourthly, the present invention also provides a non-fullerene organic solar cell, wherein the non-fullerene organic solar cell includes an active layer containing an acceptor material and a donor material, wherein the donor material is the aforementioned polymer donor material, and the acceptor material is a non-fullerene acceptor material, such as Y6, the structural formula of which is shown in the figure below:

[0077]

[0078] Wherein, R1 is 2-ethylhexyl and R4 is n-undecyl.

[0079] In this invention, the other components and preparation methods of the non-fullerene polymer solar cell are all conventional in the field.

[0080] As an optional technical solution of the present invention, the mass ratio of the donor material to the acceptor material is 1:(1.0 to 1.2), specifically it can be 1:1.0, 1:1.05, 1:1.1 or 1:1.2, etc., and is not limited here.

[0081] As an optional technical solution of the present invention, the annealing temperature of the organic solar cell is 100℃~120℃; specifically, it can be 100℃, 110℃ or 120℃, etc., or other values ​​within the above range.

[0082] Preferably, in polymer solar cells based on the structure ITO / PEDOT:PSS / Formula (I-1):Y6 / PDINN / Ag, the annealing temperature is preferably 110°C. In polymer solar cells based on the structure ITO / PEDOT:PSS / Formula (I-2):Y6 / MoO3 / Ag, the annealing temperature is preferably 110°C.

[0083] To further illustrate the present invention, the following embodiments will be described in detail.

[0084] Example 1

[0085] This embodiment provides a method for preparing the polymer donor shown in formula (I 1), including the following steps:

[0086] (1) Synthesis of compound 2:

[0087] Thiophene (4.2 g / 50 mmol) was added to anhydrous tetrahydrofuran solvent. The air in the reaction system was removed, and nitrogen was introduced for protection. Butyllithium (30 mL / 60 mmol) was added dropwise at -78 °C, and the reaction was maintained at -78 °C for 2 hours. A slight excess of 1-bromo-2-butyloctane (14.88 g / 60 mmol) was added, and the reaction was continued at room temperature for 14 hours. After the reaction was stopped, the mixture was extracted with dichloromethane (90 mL × 3) and water (90 mL). The solution was purified by column chromatography with petroleum ether to obtain a colorless liquid, which was compound 2 (2-(2-butyloctyl)thiophene) (11.59 g / 46 mmol). The yield was 92%.

[0088] Compound 2 1 H NMR spectrum 1 H NMR (400MHz, CDCl3) δ7.09(s,1H),6.90(t,1H),6.75(d,1H),2.74(d,2H),1.61(m,1H),1.40-1.13(m,16H),0.95-0.80(m,6H).

[0089] (2) Synthesis of compound 3:

[0090] Compound 2 (2-(2-butyloctyl)thiophene, (10.08 g / 40 mmol)) was dissolved in anhydrous tetrahydrofuran. The reaction system was dried under vacuum and protected with sufficient nitrogen. Lithium n-butyl (24 mL / 48 mmol) was added dropwise at -78 °C, and the reaction was maintained at -78 °C for 2 hours. Isobutane bromo (6.53 g / 48 mmol) was then added, and the reaction was continued at room temperature for 14 hours. After the reaction was stopped, the mixture was extracted with dichloromethane (90 mL × 3) and water (90 mL). The solution was passed through a petroleum ether column chromatography. The mono-substituted product was distilled off under reduced pressure, leaving a small amount of the bi-substituted 2-butyloctyl thiophene product from the previous step. The purified liquid was compound 3 (2-isobutyl-5-(2-butyloctyl)thiophene) (10.23 g / 33.2 mmol). The yield was 83%.

[0091] Compound 3 1 H NMR spectrum 1 H NMR (400MHz, CDCl3) δ6.92(t,1H),6.75(d,1H),2.81-2.62(m,2H),1.71-1.52(m,2H),1.40-1.28(m,14H),0.95-0.79(m,6H).

[0092] (3) Synthesis of compound 4:

[0093] 2,5-Dibromothiophene-3,4-dicarboxylic acid (3.3 g / 10 mmol) was dissolved in anhydrous dichloromethane. The air in the reaction system was removed under vacuum, and sufficient nitrogen was introduced for protection. A catalytic amount of DMF was added, and the reaction was carried out at 50 °C for 2 hours. During the reaction, appropriate amounts of gas generated in the system were released into a fume hood. The reacted system was evaporated to dryness, and residual DMF was removed using a vacuum pump. The dried solid was dissolved in anhydrous dichloromethane, and a slight excess of compound 3 (2-isobutyl-5-(2-butyloctyl)thiophene) (3.39 g / 11 mmol) was added. The air in the reaction system was removed under vacuum, and sufficient nitrogen was introduced for protection. Anhydrous aluminum chloride (5.33 g / 40 mmol) was added batch by batch at 0 °C, and the reaction was observed by TLC. The reaction system was quenched after approximately 40 minutes. After the reaction was stopped, the system was extracted with dichloromethane (90 mL × 3) and water (90 mL). The compound 4 (2.71 g / 4.5 mmol) was obtained by column chromatography with petroleum ether:dichloromethane in a 3:1 (v / v) ratio. The yield was 45%.

[0094] Compound 4 1 H NMR spectrum 1H NMR (400MHz, CDCl3) δ3.33-3.22(m,4H),1.80(s,1H),1.50(s,1H),1.32-1.26(d,16H),1.03-0.88(m,12H).

[0095] (4) Synthesis of compound 5:

[0096] Compound 4 (2.41 g / 4 mmol) was dissolved in anhydrous toluene with a slight excess of 2-tributyltin thiophene (4.2 ml / 8.4 mmol) and tetrakis(triphenylphosphine) palladium (3.23 g / 0.28 mmol) under nitrogen protection and refluxed for 25 hours. After reflux, extraction was performed. The solution was purified by polar chromatography using a 3:1 volume ratio of petroleum ether to dichloromethane to give a pale yellow solid 5 (2.21 g / 3.64 mmol). Yield: 91%.

[0097] Compound 5 1 H NMR spectrum 1 H NMR (400MHz, CDCl3) δ7.09(m,2H),6.92(m,2H),6.57(m,2H),3.45(m,4H),1.60-1.28(m,20H),0.97-0.87(m,10H).

[0098] (5) Synthesis of compound 6:

[0099] Compound 5 (1.82 g / 3 mmol) was dissolved in a suitable amount of chloroform. N-bromosuccinimide (NBS) (1.18 g / 6.6 mmol) dissolved in a small amount of DMF was added dropwise, and the reaction was carried out in the dark for 14 hours. The reaction mixture was quenched and extracted. The mixture was then purified by column chromatography using petroleum ether:dichloromethane (3:1) to give compound 6 (2.11 g / 2.76 mmol). Yield: 92%.

[0100] Compound 6 1 H NMR spectrum as shown Figure 1 As shown, 1 H NMR (400MHz, CDCl3) δ7.45(t,2H),7.07(t,2H),3.31-3.24(m,4H),1.54-1.01(m,20H),1.09-0.85(m,10H).

[0101] (6) Synthesis of polymer formula (Ⅰ-1):

[0102] Compound 6 (76.601 mg / 0.1 mmol) and compound 7 (94.013 mg / 0.1 mmol) were dissolved in 5 mL of anhydrous toluene. The reaction system was evacuated for 10 minutes, and then 5 mg of tetraphenylphosphine palladium catalyst was added under nitrogen protection. The reaction system was heated to 110 °C and stirred at this temperature for 20 hours. After the reaction was completed, the polymer reaction system dissolved in toluene was promptly precipitated by dropping it dropwise into methanol using a glass dropper at a relatively high temperature. The mixture was stirred thoroughly for about 25 minutes, and the precipitated black polymer solid was filtered through a Buchner funnel. The filtered black polymer solid was placed in a clean beaker and dried in an oven under vacuum at 45 °C. The dried polymer was dissolved in an appropriate amount of chloroform and stirred thoroughly. The solution was then dropped into a chromatographic column cleaned of coarse silica gel particles, and the fully dissolved polymer was processed by column chromatography. The collected chloroform solution of the polymer that is soluble in chloroform at room temperature was evaporated and precipitated again. The same method was used to filter it again. The black polymer solid after filtration was dried in an oven, which is the polymer shown in formula (I-1). The mass of the obtained polymer was 84.89 mg, and the yield was 68%.

[0103] Example 2

[0104] This embodiment provides a method for preparing the polymer donor shown in formula (I-2), including the following steps:

[0105] (1) Synthesis of compound 8

[0106] Thiophene (4.2 g / 50 mmol) was added to anhydrous tetrahydrofuran solvent. The air in the reaction system was removed, and nitrogen was introduced for protection. Butyllithium (30 mL / 60 mmol) was added dropwise at -78 °C, and the reaction was maintained at -78 °C for 2 hours. Then, isooctane bromo was added (11.52 g / 60 mmol), and the mixture was stirred overnight at room temperature. After stopping the reaction, extraction was performed. The petroleum ether was purified by column chromatography to give a colorless liquid compound 8 (2-(2-ethylhexyl)thiophene) (9.21 g / 47 mmol). The yield was 94%.

[0107] Compound 8 1 H NMR spectrum 1 H NMR (400MHz, CDCl3) δ7.07(s,1H),7.04(d,1H),6.79(d,1H),2.74(d,2H),1.57(m,1H),1.29-1.26(m,8H),0.90-0.88(t,6H).

[0108] (2) Synthesis of compound 9

[0109] Compound 8 (2-(2-ethylhexyl)thiophene (7.84 g / 40 mmol)) was dissolved in anhydrous tetrahydrofuran. The reaction system was dried under vacuum and purged with sufficient nitrogen for protection. Butyllithium (24 ml / 48 mmol) was added dropwise at -78 °C, and the reaction was maintained at -78 °C for 2 hours. Then, 1-bromo-2-butyloctane (11.90 g / 48 mmol) was added, and the mixture was stirred overnight at room temperature. Extraction was performed. The solution was filtered through a petroleum ether column. The crude product was dried by rotary evaporation. The single-sided substituted product was then separated by vacuum distillation, leaving a small amount of the double-sided 2-butyloctyl substituted thiophene product produced in the previous step. The pure liquid compound 9 (2-(2-ethylhexyl)-5-(2-butyloctyl)thiophene) (12.23 g / 33.6 mmol) was obtained, with a yield of 84%.

[0110] Compound 9 1 H NMR spectrum 1 H NMR (400MHz, CDCl3) δ6.92(t,1H),6.75(d,1H),2.76-2.59(m,2H),1.72-1.55(m,4H),1.40-1.28(m,24H),0.98-0.82(m,12H).

[0111] (3) Synthesis of compound 10

[0112] 2,5-Dibromothiophene-3,4-dicarboxylic acid (3.3 g / 10 mmol) was dissolved in anhydrous dichloromethane. The air in the reaction system was removed under vacuum, and sufficient nitrogen was introduced for protection. A catalytic amount of DMF was added, and the reaction was carried out at 50 °C for 2 hours. During the reaction, appropriate amounts of gas generated in the system were released into a fume hood. The reacted system was evaporated to dryness, and residual DMF was removed using a vacuum pump. The dried solid was dissolved in anhydrous dichloromethane, and a slight excess of compound 9 (2-isobutyl-5-(2-butyloctyl)thiophene) (4.0 g / 11 mmol) was added. The air in the reaction system was removed under vacuum, and sufficient nitrogen was introduced for protection. Anhydrous aluminum chloride (5.33 g / 40 mmol) was added batch by batch at 0 °C, and the reaction was observed by TLC. The reaction system was quenched after approximately 40 minutes. After the reaction was stopped, the system was extracted with dichloromethane (90 mL × 3) and water (90 mL). The solution was purified by column chromatography with petroleum ether:dichloromethane in a 3:1 ratio to give a pale yellow solid (2.63 g / 4 mmol). Yield: 40%.

[0113] Compound 10 1 H NMR spectrum 1H NMR (400MHz, CDCl3) δ3.33-3.22(m,4H), 1.77-1.49(m,4H), 1.32-1.25(m,18H), 1.01-0.85(m,16H).

[0114] (4) Synthesis of compound 11

[0115] Compound 10 (1.97 g / 3 mmol) was dissolved in toluene with a slight excess of 2-tributyltin thiophene (3.3 ml / 6.6 mmol). The air in the reaction system was removed, and nitrogen was introduced for protection. A catalytic amount of tetra-triphenylphosphine palladium was added, and the reaction was carried out at 110 °C for 26 hours. The reaction was then stopped. Extraction was performed. The product was obtained by column chromatography using petroleum ether:dichloromethane (3:1). The product was a pale yellow solid (1.83 g / 2.76 mmol). Yield: 92%.

[0116] Compound 11 1 H NMR spectrum 1 H NMR (400MHz, CDCl3) δ7.10(m,2H),6.90(m,2H),6.57(m,2H),3.45(m,4H),1.61-1.28(m,30H),0.94-0.85(m,14H).

[0117] (5) Synthesis of compound 12

[0118] Compound 11 (1.33 g / 2 mmol) was dissolved in a suitable amount of chloroform. N-bromosuccinimide (NBS) (0.78 g / 4.4 mmol) dissolved in a small amount of DMF was added dropwise, and the reaction was carried out in the dark for 14 hours. The reaction mixture was quenched and extracted. The mixture was then passed through a column chromatography column using petroleum ether:dichloromethane (3:1). Recrystallization yielded a high-purity yellow solid, compound 12 (1.49 g / 1.82 mmol), in 91% yield.

[0119] Compound 12 1 H NMR spectrum as shown Figure 2 As shown, 1 H NMR (400MHz, CDCl3) δ7.45(t,2H),7.07(t,2H),3.31-3.29(m,4H),1.41-1.26(m,30H),0.97-0.87(m,14H).

[0120] (6) Synthesis of the polymer shown in formula (I-2)

[0121] Compound 7 (94.013 mg / 0.1 mmol) and compound 12 (82.207 mg / 0.1 mmol) were dissolved in 5 mL of anhydrous toluene. The reaction system was evacuated for 10 minutes, and then tetrakis(triphenylphosphine)palladium catalyst (5 mg) was added under nitrogen protection. The reaction system was heated to 110 °C and stirred at this temperature for 20 hours. After the reaction was completed, the polymer reaction system dissolved in toluene was promptly precipitated by dropping it dropwise into methanol using a glass dropper at a relatively high temperature. The mixture was stirred thoroughly for about 25 minutes, and the precipitated black polymer solid was filtered through a Buchner funnel. The filtered black polymer solid was placed in a clean beaker and dried in an oven under vacuum at 45 °C. The dried polymer was dissolved in an appropriate amount of chloroform and stirred thoroughly. The solution was then dropped into a chromatographic column 8 after washing coarse silica gel particles, and the fully dissolved polymer was processed by column chromatography. The collected chloroform solution of the polymer that is soluble in chloroform at room temperature was evaporated to dryness, dissolved, and then precipitated again. The same method was used to filter it again, and a black polymer solid was obtained after filtration, which is the polymer shown in formula (I-2). The mass of the obtained polymer was 82.18 mg, and the yield was 63%.

[0122] Test case

[0123] (1) Optical and electrochemical performance testing

[0124] The polymer donors obtained in Examples 1 and 2 were subjected to optical and electrochemical performance tests. The UV-Vis absorption of formulas (I-1) and (I-2) in solution (diluted chloroform solution) was measured using a spectrophotometer, and the results are as follows. Figure 3 As shown, both equations (Ⅰ-1) and (Ⅰ-2) exhibit relatively wide absorption ranges, with maximum absorption peaks at 612 nm and 610 nm, respectively. From the formula Eg... opt =1240 / λ onset Their optical band gaps can be obtained. The absorption sideband of formula (Ⅰ-1) is 662 nm, corresponding to an optical band gap of 1.87 eV. The absorption sideband of formula (Ⅰ-2) is 658 nm, corresponding to an optical band gap of 1.89 eV. The relevant results are shown in Table 1. The electronic energy levels of polymers (Ⅰ-1) and (Ⅰ-2) were determined by cyclic voltammetry, and the results are as follows: Figure 4 , Figure 5 As shown, based on the cyclic voltammetry data of the material, the highest occupied orbital and the lowest unoccupied orbital in equations (Ⅰ-1) and (Ⅰ-2) can be calculated using the measured initial redox potentials. In the measurement process, Fc / Fc was selected. + As an internal standard, Fc / Fc can be obtained through measurement. + The redox potential with Ag / AgCl as the reference electrode is 0.44 eV, while the Fc / Fc +The energy level is taken as 4.8 eV below the vacuum level, therefore we use the following calculation formula: E HOMO / LUMO =-e(E ox / red The electronic energy levels of the molecule were calculated using +4.36 eV, and the calculated data are listed in Table 1. The calculated HOMO and LUMO energy levels of equations (I-1) and (I-2) are -5.53 eV / -5.52 V and -3.66 eV / -3.67 eV, respectively.

[0125] Table 1 Optical property parameters of polymers of formula (I-1) and (I-2)

[0126]

[0127] (2) Photovoltaic performance testing

[0128] Polymer solar cells are fabricated using formula (I-1) or (I-2) as the donor material and Y6 as the acceptor material, according to the formula ITO / PEDOT:PSS / polymer:Y6 / PDINN / Ag. In this formula, PEDOT:PSS is the anode modification layer, and PDINN...

[0129] (N,N'-Bis{3-[3-(Dimethylamino)propylamino]propyl}perylene-3,4,9,10-tetracarboxylic diimide) was used as the cathode modification layer. The specific process was as follows: First, an ITO-containing glass substrate was ultrasonically cleaned sequentially with deionized water, acetone, and isopropanol for 30 min. After cleaning, the glass substrate was dried and treated with a UVO (ultraviolet ozone) device. A PEDOT:PSS aqueous solution was spin-coated onto the ITO surface of the previously treated glass substrate and annealed at 150°C for 15 min to obtain a PEDOT:PSS film. A pre-dissolved and thoroughly stirred photoactive layer solution (8 mg of polymer donor and 9.6 mg of acceptor Y6 dissolved in 1 mL of chloroform solvent, with 5 μL of chloronaphthalene added as an additive) was spin-coated onto the PEDOT:PSS film at 3000 rpm for 30 s and annealed at 110°C for 10 min. Finally, a methanol solution of PDINN was spin-coated onto the photoactive layer as the cathode modification layer. Finally, in a vacuum (approximately 5.0 × 10⁻⁶), -5 High-purity metallic Ag is vapor-deposited onto a PDINN layer in a Pa) environment to serve as the cathode.

[0130] The photovoltaic performance of organic solar cell devices was tested under a standard simulated xenon lamp light source (AM 1.5G, 100mW / cm²). -2 The test was conducted in a nitrogen-filled glove box using a Keithley 2450 test station at AM 1.5G and 100mW cm⁻¹.-2 The current-voltage curve of the device was obtained under the test conditions, such as... Figure 6 As shown. The average efficiency of the device was obtained from testing 20 independent devices fabricated under the same conditions. The effective area of ​​the device, measured by optical microscopy, is 4.7 mm². 2 .

[0131] The external quantum efficiency of the organic solar cell device was measured using an external quantum efficiency measurement system, and the light intensity at each wavelength was calibrated using a standard monocrystalline silicon photovoltaic cell. For example... Figure 7 As shown, photovoltaic devices based on Equation (I-1):Y6 and Equation (I-2):Y6 both exhibit a maximum external quantum efficiency of 84% at approximately 570 nm. Furthermore, the external quantum efficiency of devices based on Equation (I-1):Y6 is above 70% in the wavelength range of 435 nm to 832 nm, while that of devices based on Equation (I-2):Y6 is above 70% in the wavelength range of 451 nm to 820 nm. The short-circuit current densities of photovoltaic devices based on Equation (I-1):Y6 and Equation (I-2):Y6, obtained by integrating the external quantum efficiency curves, are 24.05 mA cm⁻¹. -2 and 24.98mA cm -2 The results showed that the short-circuit current value obtained by the current-voltage test was consistent with the short-circuit current value within a reasonable error range, proving the reliability of the photovoltaic performance test results.

[0132] Table 2 Test Results

[0133]

[0134] The data in the table above show that organic solar cells based on polymer donor formula (Ⅰ-1) or formula (Ⅰ-2) and non-fullerene acceptor Y6 all exhibit high photoelectric conversion efficiency, while those based on fullerene acceptor PC... 71 Organic solar cells fabricated by BM have low photoelectric conversion efficiency.

[0135] This invention also tested and measured the photocurrent density (J) of organic solar cell devices based on formula (Ⅰ-1):Y6 and formula (Ⅰ-2):Y6. ph ) and effective voltage (V eff The relationship between photocurrent density J and photocurrent density J. ph Defined as J ph =J L -J D J L With J D These represent the current density under illumination and darkness, respectively. Effective voltage V. eff Defined as V eff =V0-V biasWhere V0 is defined as the voltage when the photocurrent density is zero, V bias It is defined as the applied bias voltage. Typically, when the effective voltage is higher than 2V, charge carriers move rapidly to the corresponding electrodes, and the current density at this point can be considered as the saturation photocurrent density. At this point, all charge carriers are extracted and collected, and carrier recombination is minimized. Therefore, using J... ph / J sat The ratio can be used to measure the efficiency of exciton dissociation and carrier collection. For example... Figure 8 As shown, under short-circuit current conditions, the optimized device based on Equation (Ⅰ-1):Y6 calculates J... ph / J sat The value is 97.2%, and the J value is calculated based on the device of Equation (Ⅰ-2):Y6. ph / J sat The value is 98.6%. The test results show that both devices based on (Ⅰ-1):Y6 and (Ⅰ-2):Y6 have high exciton dissociation efficiency, which is one of the main reasons for their high fill factor.

[0136] (3) Morphological test

[0137] The surface morphology and microstructure of the active layers based on formula (Ⅰ-1):Y6 and formula (Ⅰ-2):Y6 were studied using atomic force microscopy (AFM) and transmission electron microscopy (TEM), respectively.

[0138] AFM test results are as follows Figure 9 As shown, the active layers based on formula (I-1):Y6 and formula (I-2):Y6 exhibit good solubility and crystallinity, and the donor-acceptor blend film shows excellent phase separation, forming a suitable phase separation size. The surface roughness of the AFM height map of the formula (I-1):Y6 and formula (I-2):Y6 blend film is 4.53 nm and 3.37 nm, respectively, and the surface roughness of the phase map is 3.96 nm and 3.63 nm, respectively, proving that it has a relatively flat and smooth active layer morphology, confirming the good miscibility between the polymer donor and acceptor materials.

[0139] TEM test results as follows Figure 10 As shown, the active layer based on Equation (I-1):Y6 and Equation (I-2):Y6 exhibits a nanoscale fibrous network structure, which is beneficial for the efficient dissociation and transport of charge carriers.

[0140] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A polymer donor for a non-fullerene organic solar cell, characterized in that, The polymer donor has a structure as shown in formula (I-1) or (I-2): Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, R3 is 2-methylpropyl, and n is a natural number between 5 and 100; The synthetic route for the compound shown in formula (I-1) is as follows: And / or, the synthetic route for the compound shown in formula (I-2) is as follows: Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, and R3 is 2-methylpropyl.

2. A method for preparing a polymer donor for a non-fullerene organic solar cell according to claim 1, characterized in that, It is obtained by polymerization of compound 6 or compound 12 with compound 7 via the Stieler reaction, as shown below. Wherein, R1 is 2-ethylhexyl, R2 is 2-butyloctyl, and R3 is 2-methylpropyl.

3. The method for preparing the polymer donor according to claim 2, characterized in that, The Stieler reaction is carried out at a temperature of 100℃ to 110℃ and for a time of 4h to 24h.

4. The method for preparing the polymer donor according to claim 3, characterized in that, The Stieler reaction is carried out under the catalysis of a palladium catalyst.

5. The application of a polymer donor for a non-fullerene organic solar cell according to claim 1 or a polymer donor for a non-fullerene organic solar cell prepared by any one of claims 2-4 in an organic solar cell.

6. An organic solar cell, characterized in that, The active layer includes a donor material and an acceptor material, wherein the donor material is the polymer donor according to claim 1 or the polymer donor prepared by the preparation method according to any one of claims 2-4, and the acceptor material is a non-fullerene acceptor material.

7. The organic solar cell according to claim 6, characterized in that, The mass ratio of the donor material to the acceptor material is 1:(1.0 to 1.2).

8. An electrical appliance, characterized in that, Including the organic solar cell described in claim 6 or 7.

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