TWI753676B - Conjugated polymers and organic photovoltaic elements - Google Patents

Abstract

A conjugated polymer and an organic photovoltaic element comprising the aforementioned conjugated polymer. The conjugated polymer contains repeating units represented by formula (I). The conjugated polymers of the present invention have wide energy gaps and can be used as electron-donor materials in organic photovoltaic elements.

Description

Conjugated polymers and organic photovoltaic elements

The present invention relates to a conjugated polymer and an organic photovoltaic element comprising the aforementioned conjugated polymer, in particular to a conjugated polymer with electron-deficient heterocyclic quinoxaline and imide central structures and organic photovoltaic elements comprising the aforementioned conjugated polymers.

With the evolution of the times, the consumption of energy resources such as coal, oil, natural gas and nuclear energy is increasing day by day, and the energy crisis has also emerged relatively. Solar power is a renewable and environmentally friendly way of power generation that can reduce environmental pollution. The first-generation solar cells are based on silicon crystals and have high power conversion efficiency (PCE). The second generation is a thin-film type cadmium telluride (CdTe thin-film) solar cell, but the toxicity of its raw materials and the production process have great pollution to the environment. Therefore, the third generation of organic solar cells is born, which includes dye-sensitized solar cells (DSSC), nanocrystalline cells and organic photovoltaics (OPV).

The production of organic photovoltaic elements (OPV) can use dip coating, spin coating, slot coating, screen printing, inkjet printing, etc. Therefore, organic photovoltaics (OPVs) are easier to achieve at low cost and in large-scale production. Among them, the organic optoelectronic acceptor material and the conjugated polymer electron donor material (copolymer) are used as the material of the main photovoltaic absorption layer when the new generation of organic photovoltaic elements are fabricated. Among them, the aforementioned organic photovoltaic elements have several advantages: (1) light weight and low production cost; (2) flexibility; (3) strong element structure design; (4) suitable for liquid phase process, can be large Area wet coating.

Although the existing organic photovoltaic elements have many advantages, and the development of the diversity of copolymers in the light absorption layer has brought the improvement of the energy conversion efficiency (PCE) to a certain level. However, the development of electron acceptor materials in existing organic photovoltaic devices is mostly based on fullerene derivatives (PC61BM and PC71BM), which limits the compatibility of electron donor materials and electron acceptor materials. In addition, fullerene derivatives themselves also have disadvantages such as easy dimerization under light, easy crystallization when heated, weak absorption in the visible light region, difficult structural modification and purification, and high price. In recent years, all walks of life have actively developed new non-fullerene acceptor materials in order to achieve higher performance. However, since the new non-fullerene acceptor material is a narrow energy gap material, the matching electron donor material needs to have a wide energy gap.

Therefore, how to develop an electron donor material with a wide energy gap, thereby improving the energy level matching of existing electron donor materials and improving the absorption in the visible light region, further To improve the power conversion efficiency (PCE) of organic photovoltaic elements has become the goal of current research.

Therefore, the first object of the present invention is to provide a conjugated polymer. The conjugated polymers have wide energy gaps and can be used as electron-donor materials in organic photovoltaic elements.

其中，p與q分別為0、1或2；R¹與R²分別為H、F、Cl、R⁶、-CN、-OR⁷、-SR⁸、-C(=O)OR⁹、-Si(R¹⁰)₃或雜芳基；R³為H、R⁶、芳基或雜芳基； R⁶至R¹⁰分別為未經取代或經至少一R¹⁹取代的C₄~C₃₀直鏈、支鏈或環狀烷基、未經取代或經至少一R¹⁹取代的C₄~C₃₀烯基、或未經取代或經至少一R¹⁹取代的C₄~C₃₀炔基；R¹⁹為鹵素、-CN或-SiR²⁰R²¹R²²；R²⁰至R²²分別為C₁~C₃₀烷基；及Ar¹至Ar³分別為亞芳基(arylene)或亞雜芳基(heteroarylene)。 Thus, the conjugated polymer of the present invention comprises a repeating unit represented by the following formula (I):

Wherein, p and q are respectively 0, 1 or 2; R ¹ and R ² are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ , - Si(R ¹⁰ ) ₃ or heteroaryl; R ³ is H, R ⁶ , aryl or heteroaryl; R ⁶ to R ¹⁰ are respectively unsubstituted or C ₄ ～C ₃₀ substituted by at least one R ¹⁹ Chain, branched or cyclic alkyl, unsubstituted or substituted by at least one R ¹⁹ C ₄ ～C ₃₀ alkenyl, or unsubstituted or by at least one R ¹⁹ substituted C ₄ ～C ₃₀ alkynyl; R ¹⁹ is halogen, -CN or -SiR ²⁰ R ²¹ R ²² ; R ²⁰ to R ²² are respectively C ₁ -C ₃₀ alkyl; and Ar ¹ to Ar ³ are respectively arylene or heteroarylene ( heteroarylene).

Therefore, the second object of the present invention is to provide an organic photovoltaic element.

Thus, the organic photovoltaic element of the present invention comprises the aforementioned conjugated polymer.

The effect of the present invention is: because the conjugated polymer of the present invention has a wide energy gap and has an electron-deficient heterocyclic quinoxaline and imide central structure, it has good stackability, and can further strengthen its use as an electron donor. The electron transfer ability of the material. Therefore, the organic photovoltaic element using the conjugated polymer of the present invention as the electron donor material will have higher energy conversion efficiency (PCE).

In addition, since the conjugated polymer of the present invention has a certain solubility for chlorine-free solvents. Therefore, when the conjugated polymer of the present invention is used as the electron donor material and the non-fullerene electron acceptor material, a relatively environmentally friendly chlorine-free solvent can be used to dissolve it in the process, and it is suitable for large-area coating to facilitate The subsequent coating process is carried out.

The content of the present invention will be described in detail below:

[Conjugated polymer]

其中，p與q分別為0、1或2；R¹與R²分別為H、F、Cl、R⁶、-CN、-OR⁷、-SR⁸、-C(=O)OR⁹、-Si(R¹⁰)₃或雜芳基；R³為H、R⁶、芳基或雜芳基；R⁶至R¹⁰分別為未經取代或經至少一R¹⁹取代的C₄~C₃₀直鏈、支鏈或環狀烷基、未經取代或經至少一R¹⁹取代的C₄~C₃₀烯基、或未經取代或經至少一R¹⁹取代的C₄~C₃₀炔基；R¹⁹為鹵素、-CN或-SiR²⁰R²¹R²²；R²⁰至R²²分別為C₁~C₃₀烷基；及Ar¹至Ar³分別為亞芳基或亞雜芳基。 The conjugated polymer of the present invention comprises a repeating unit represented by the following formula (I):

Wherein, p and q are respectively 0, 1 or 2; R ¹ and R ² are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ , - Si(R ¹⁰ ) ₃ or heteroaryl; R ³ is H, R ⁶ , aryl or heteroaryl; R ⁶ to R ¹⁰ are respectively unsubstituted or C ₄ ～C ₃₀ substituted by at least one R ¹⁹ Chain, branched or cyclic alkyl, unsubstituted or substituted by at least one R ¹⁹ C ₄ ～C ₃₀ alkenyl, or unsubstituted or by at least one R ¹⁹ substituted C ₄ ～C ₃₀ alkynyl; R ¹⁹ is halogen, -CN or -SiR ²⁰ R ²¹ R ²² ; R ²⁰ to R ²² are respectively C ₁ -C ₃₀ alkyl; and Ar ¹ to Ar ³ are respectively arylene or heteroarylene.

Preferably, p and q are 1 respectively.

，且R⁴與R⁵分別為H、F、Cl、R⁶、-CN、-OR⁷、-SR⁸、-C(=O)OR⁹、-Si(R¹⁰)₃、芳基或雜芳基。 Preferably, Ar ¹ is

, and R ⁴ and R ⁵ are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ , -Si(R ¹⁰ ) ₃ , aryl or hetero Aryl.

，且n₁為1、2、3、4或5；及R¹¹為H、F、Cl、R⁶、-CN、-OR⁷、-SR⁸、-C(=O)OR⁹或-Si(R¹⁰)₃。 More preferably, the aryl group in R ³ to R ⁵ is

, and n ₁ is 1, 2, 3, 4 or 5; and R ¹¹ is H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ or -Si (R ¹⁰ ) ₃ .

，且n₂為1、2、3、4或5；及R¹²至R¹⁴分別為H、F、Cl、R⁶、-CN、-OR⁷、-SR⁸、-C(=O)OR⁹或-Si(R¹⁰)₃。 More preferably, the heteroaryl group in R ¹ to R ⁵ is

, and n ₂ is 1, 2, 3, 4 or 5; and R ¹² to R ¹⁴ are H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR, respectively ⁹ or -Si(R ¹⁰ ) ₃ .

或-OR⁷，且R¹與R²中至少一者為

或-OR⁷。在R¹與R²中，又更佳地，n₂為1。又更佳地，R¹²至R¹⁴分別為H、Cl或R⁶且R¹²至R¹⁴中至少一者為R⁶。又更佳地，R¹²至R¹⁴分別為H、Cl或C₄~C₃₀支鏈烷基且R¹²至R¹⁴中至少一者為C₄~C₃₀支鏈烷基。又更佳地，R¹²至R¹⁴分別為H、Cl或C₉~C₁₅支鏈烷基且R¹²至R¹⁴中至少一者為C₉~C₁₅支鏈烷 基。又更佳地，R⁷為C₄~C₃₀直鏈或支鏈烷基。又更佳地，R⁷為C₆~C₁₃直鏈或支鏈烷基。 Still more preferably, R ¹ and R ² are H,

or -OR ⁷ , and at least one of R ¹ and R ² is

or -OR ⁷ . In R ¹ and R ² , more preferably, n ₂ is 1. Still more preferably, R ¹² to R ¹⁴ are each H, Cl or R ⁶ and at least one of R ¹² to R ¹⁴ is R ⁶ . Still more preferably, R ¹² to R ¹⁴ are respectively H, Cl or C ₄ -C ₃₀ branched alkyl and at least one of R ¹² to R ¹⁴ is C ₄ -C ₃₀ branched alkyl. Still more preferably, R ¹² to R ¹⁴ are respectively H, Cl or C ₉ -C ₁₅ branched alkyl and at least one of R ¹² to R ¹⁴ is C ₉ -C ₁₅ branched alkyl. Still more preferably, R ⁷ is a C ₄ -C ₃₀ straight-chain or branched-chain alkyl group. Still more preferably, R ⁷ is a C ₆ -C ₁₃ straight-chain or branched-chain alkyl group.

或-OR⁷時，會使共軛聚合物具有更良好的堆疊性，進而更能強化其作為電子給體材料時的電子傳遞能力。因此，所得到有機光伏元件會具有更高的能量轉換效率(PCE)。 It is particularly worth mentioning that when at least one of R ¹ and R ² is

Or -OR ⁷ , the conjugated polymer will have better stackability, which will further enhance its electron transfer ability as an electron donor material. Therefore, the resulting organic photovoltaic element will have a higher power conversion efficiency (PCE).

。在R⁴與R⁵中，又更佳地，n₂為1。又更佳地，R¹²至R¹⁴分別為H、F或R⁶且R¹²至R¹⁴中至少一者為R⁶。又更佳地，R¹²至R¹⁴分別為H、F或C₄~C₃₀支鏈烷基且R¹²至R¹⁴中至少一者為C₄~C₃₀支鏈烷基。又更佳地，R¹²至R¹⁴分別為H、F或C₁₁~C₁₈支鏈烷基且R¹²至R¹⁴中至少一者為C₁₁~C₁₈支鏈烷基。 Still more preferably, R ⁴ and R ⁵ are respectively

. Still more preferably, n ₂ is 1 in R ⁴ and R ⁵ . Still more preferably, R ¹² to R ¹⁴ are each H, F or R ⁶ and at least one of R ¹² to R ¹⁴ is R ⁶ . Still more preferably, R ¹² to R ¹⁴ are respectively H, F or C ₄ -C ₃₀ branched alkyl and at least one of R ¹² to R ¹⁴ is C ₄ -C ₃₀ branched alkyl. Still more preferably, R ¹² to R ¹⁴ are respectively H, F or C ₁₁ -C ₁₈ branched alkyl and at least one of R ¹² to R ¹⁴ is C ₁₁ -C ₁₈ branched alkyl.

或

且n₃與n₄分別為1、2或3；及R¹⁵至R¹⁸分別為H、F、Cl、R⁶、-CN、-OR⁷、-SR⁸、-C(=O)OR⁹、芳基或雜芳基。又更佳地，n₃與n₄分別為1。又更佳地，Ar²與Ar³分別為

。 More preferably, Ar ² and Ar ³ are respectively

or

and n ₃ and n ₄ are respectively 1, 2 or 3; and R ¹⁵ to R ¹⁸ are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ , aryl or heteroaryl. Still more preferably, n ₃ and n ₄ are each 1. Still more preferably, Ar ² and Ar ³ are respectively

.

Preferably, R ³ is R ⁶ . More preferably, R ³ is C ₄ -C ₃₀ straight chain alkyl. Still more preferably, R ³ is a C ₆ -C ₁₀ straight-chain alkyl group.

[Organic photovoltaic element]

The organic photovoltaic element of the present invention contains the aforementioned conjugated polymer.

Preferably, the organic photovoltaic element comprises a substrate, a negative electrode stacked on the substrate, an electron transport layer stacked on the negative electrode, an active layer stacked on the electron transport layer, and an active layer stacked on the active layer. an upper hole transport layer, and a positive electrode stacked over the hole transport layer, and the active layer includes the conjugated polymer.

Preferably, the organic photovoltaic element comprises a substrate, a positive electrode stacked on the substrate, a hole transport layer stacked on the positive electrode, an active layer stacked on the hole transport layer, and a layer stacked on the positive electrode. An electron transport layer over the active layer, and a negative electrode laminated over the electron transport layer, and the active layer includes the conjugated polymer.

70: Substrate

80: negative pole

91: electron transport layer

92: Active layer

93: hole transport layer

100: positive

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a spectrogram illustrating the liquid state (soln.) and solid state of the conjugated polymers of Examples 3 to 5 (film) UV-Vis absorption spectrum; FIG. 2 is a schematic cross-sectional view illustrating the first structure of the organic photovoltaic element of the present invention; and 3 is a schematic cross-sectional view illustrating the second structure of the organic photovoltaic element of the present invention.

<Example 1>

Conjugated polymers

The repeating units contained in the conjugated polymer of Example 1 and the preparation method are as follows.

Example 1

Preparation method of compound 1 :

2,5-dibromo-3,4-dinitrothiophene (10g, 30.13mmol), tin thiophene reagent (25.86g, 69.29mmol), tris(2-methylphenyl)phosphorus (0.92g, 3.01mmol) ) and tris(dibenzylideneacetone)dipalladium (0.83 g, 0.9 mmol) were placed in a round-bottomed flask, and then toluene (150 mL) was added. Next, it was heated to 100°C under nitrogen protection and reacted for 3 hours. After the reaction was completed, the temperature was lowered and the solvent was removed by a rotary concentrator. Finally, after precipitation with methanol, compound 1 (7 g, yield: 69%) was obtained as an orange solid.

Preparation method of compound 2 :

Compound 1 (7 g, 20.69 mmol) and ethanol (140 mL) were placed in a round-bottom flask, and then tin dichloride (59 g. 310.3 mmol) was slowly poured into the flask under an ice bath. Next, the reaction was carried out at room temperature for 2 days. After the reaction is completed, neutralize with sodium bicarbonate acid-base to basicity, and then add toluene for extraction. Finally, the organic layer was dewatered with anhydrous magnesium sulfate, and then the solvent was removed with a rotary concentrator to obtain a dark brown solid compound 2 (5.6 g, yield: 97%).

Compound 2 Compound 3

The preparation method of compound 3 :

Compound 2 (5.6 g, 20.11 mmol), thionaniline (10.2 mL, 90.51 mmol) and pyridine (84 mL) were placed in a round-bottom flask, and then trimethylchlorosilane (19 mL) was slowly added dropwise under an ice bath. , 150.85 mmol). Next, the reaction was carried out at room temperature for 3 days. After the reaction was completed, poured into ice-water hydrochloric acid solution, and then added dichloromethane for extraction. Finally, the organic layer was dewatered with anhydrous magnesium sulfate, and then the solvent was removed with a rotary concentrator to obtain a dark blue solid compound 3 (5 g, yield: 81%).

The preparation method of compound 4 :

Compound 3 (5 g, 16.3 mmol) and o-xylene (75 mL) were placed in a round-bottom flask, and then dimethyl butynedicarboxylate (4 mL. 32.63 mmol) was slowly added dropwise. Next, heat under reflux until the next day. Cool after the reaction is over. Finally, first remove o-xylene with a rotary concentrator, and then purify with silica gel column chromatography (dichloromethane: n-heptane=2: 1 as eluent) to obtain yellow solid compound 4 (6 g, yield: 88%).

Compound 5

The preparation method of compound 5 :

Compound 4 (6 g, 14.4 mmol), sodium hydroxide (5.3 g, 144.06 mmol) and ethanol (110 mL) were placed in a round-bottom flask, and heated to reflux until the next day. Cool after the reaction is over. Next, it was poured into iced aqueous hydrochloric acid and the solid was collected by filtration. Finally, the solid was dried in an oven to obtain orange compound 5 (5.4 g, yield: 96%).

The preparation method of compound 6 :

Compound 5 (4.7 g, 12.1 mmol) was dissolved in acetic anhydride (50 mL). Next, it was stirred at reflux overnight. After the reaction was completed, the temperature was lowered to room temperature and poured into petroleum ether to precipitate solids. Finally, after drying by filtration, a brown solid compound 6 (3.7 g, yield: 83%) was obtained.

Compound 7

The preparation method of compound 7 :

After compound 6 (2.0 g, 5.4 mmol) was dissolved in acetic acid (40 mL), n-octylamine (2.2 mL, 13.5 mmol) was slowly added dropwise to the reaction flask at room temperature. Next, heat to 110°C and stir overnight. After the reaction temperature dropped to 70°C, acetic anhydride (20 mL) was added to the reaction flask and heated to 110°C and stirred overnight. After the reaction was completed, it was cooled to room temperature and extracted with petroleum ether and water. Finally, the organic layer was dried over anhydrous magnesium sulfate. The concentrated crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried in vacuo to obtain compound 7 (2.2 g, yield: 85%) as a brown solid.

The preparation method of compound 8 :

3-Chlorothiophene (14.2 g, 12 mmol) was first charged into a 250 mL reaction flask under nitrogen, and then 150 mL of anhydrous tetrahydrofuran was added and lowered to 0°C. Next, after adding dropwise a 2.5M n-butyllithium solution in n-hexane (4.8 mL, 12 mmol), it was maintained at 0°C for 1 hour. Next, 3-(bromomethyl)heptane (1.93 g, 10 mmol) was added dropwise. After returning to room temperature, it was stirred for 3 hours. Next, water was first added and extracted with n-heptane and dried over anhydrous magnesium sulfate, then the solid was removed by filtration and the filtrate was concentrated to remove the solvent. Finally, it was purified by silica gel column chromatography (n-heptane) to obtain compound 8 (1.8 g, yield: 78%) as a pale yellow liquid.

The preparation method of compound 9 :

Compound 8 (4.8 g, 21 mmol) and aluminum trichloride (2.8 g, 21 mmol) were charged into a 250 mL reaction vial under nitrogen. Next, after adding 100 mL of anhydrous dichloromethane, oxalic chloride (0.86 mL, 10 mmol) was added dropwise and stirred for 1 hour. Then, water was first added and extracted with dichloromethane and dried over anhydrous magnesium sulfate, then the solid was removed by filtration and the filtrate was concentrated to remove the solvent. Finally, purification by silica gel column chromatography (n-heptane/dichloromethane) gave compound 9 (3.4 g, yield: 66%) as a yellow solid.

Compound 11

The preparation method of compound 11 :

Compound 7 (1.7 g, 3.5 mmol) and iron powder (5.9 g, 105.8 mmol) were dissolved in acetic acid (60 mL) and heated to 110 °C and stirred for 3 hours. After confirming the completion of the reaction, the temperature was lowered to room temperature and filtered through celite. Next, the solid compound 10 was obtained by concentrating and draining with a rotary concentrator. Next, Compound 10 and Compound 9 (2.0 g, 3.9 mmol) were dissolved in acetic acid (30 mL), and then heated to 90° C. and stirred for 3 hours. Next, it was extracted with dichloromethane and water. Finally, the organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried under vacuum to obtain orange-red liquid compound 11 (1.8 g, yield: 55%).

Compound 11 Compound 12

The preparation method of compound 12 :

Compound 11 (1.79 g, 1.9 mmol) and N-bromosuccinimide (0.7 g, 3.9 mmol) were dissolved in tetrahydrofuran (40 mL) and heated to 45°C with stirring for one hour. After confirming the completion of the reaction, the temperature was lowered to room temperature. Next, it was extracted with dichloromethane and water. Finally, the organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried under vacuum to obtain compound 12 as a red solid (1.5 g, yield: 73%).

The preparation method of embodiment 1 :

Compound 12 (350 mg, 0.32 mmol), compound 13 (290 mg, 0.32 mmol), tris(2-furyl)phosphine (16 mg, 0.05 mmol) were dissolved in Pd2(dba) ₃ ( ₁₂ mg, 0.01 mmol) under nitrogen in anhydrous chlorobenzene (25 mL). Next, the mixture was heated under reflux with stirring for 2 hours. After the reaction was completed, the temperature was lowered to room temperature and poured into methanol to precipitate a solid. The precipitate was collected by filtration and the solid was subjected to Soxhlet extraction with methanol, acetone and chloroform sequentially. Finally, the chloroform solution was poured into methanol for reprecipitation, and the precipitate was collected by filtration. Vacuum drying gave the conjugated polymer Example 1 (430 mg, yield: 87%).

<Example 2>

Conjugated polymers

The repeating units contained in the conjugated polymer of Example 2 and the preparation method are as follows.

Example 2

The preparation method of embodiment 2 :

Compound 12 (350 mg, 0.32 mmol), compound 14 (302 mg, 0.32 mmol), tris(2-furyl)phosphine (16 mg, 0.05 mmol) were dissolved in Pd2(dba) ₃ ( ₁₂ mg, 0.01 mmol) under nitrogen in anhydrous chlorobenzene (25 mL). Next, the mixture was heated under reflux with stirring for 1 hour. After the reaction was completed, the temperature was lowered to room temperature and poured into methanol to precipitate a solid. The precipitate was collected by filtration and the solid was subjected to Soxhlet extraction with methanol, acetone and chloroform sequentially. Finally, the chloroform solution was poured into methanol for reprecipitation, and the precipitate was collected by filtration. Vacuum drying gave conjugated polymer Example 2 (450 mg, yield: 89%).

<Example 3>

Conjugated polymers

The repeating units contained in the conjugated polymer of Example 3 and the preparation method are shown below.

Example 3

Compound 15

The preparation method of compound 15 :

Compound 7 (1.2 g, 2.5 mmol) and iron powder (4.2 g, 75.0 mmol) were dissolved in acetic acid (40 mL) and heated to 110°C with stirring for 3 hours. After confirming the completion of the reaction, the temperature was lowered to room temperature and filtered through celite. Next, the solid compound 10 was obtained after concentrating and draining with a rotary concentrator. Next, compound 10 and glyoxylic acid (0.21 g, 2.3 mmol) were dissolved in acetic acid (30 mL) and stirred at room temperature overnight. After the reaction was completed, it was extracted with dichloromethane and water. Finally, the organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (chloroform), and then dried in vacuo to obtain compound 15 (1.7 g, yield: 81%) as an orange-yellow liquid.

The preparation method of compound 16 :

Compound 15 (500 mg, 1.02 mmol), 1-bromooctane (394 mg, 2.04 mmol), potassium tert-butoxide (228 mg, 2.04 mmol) and potassium iodide (40 mg, 0.21 mmol) were dissolved in dry tetrahydrofuran (30 mL). Next, the mixture was heated under reflux with stirring overnight. After completion of the reaction, use petroleum ether and water to extract. The organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried under vacuum to obtain compound 16 as an orange liquid (290 mg, yield: 47%).

The preparation method of compound 17 :

Compound 16 (280 mg, 0.46 mmol) and N-bromosuccinimide (170 mg, 0.95 mmol) were dissolved in tetrahydrofuran (10 mL). Next, it was heated to 45°C and stirred for 1 hour. After confirming the completion of the reaction, the temperature was lowered to room temperature. Next, it was extracted with dichloromethane and water. Finally, the organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried in vacuo to obtain compound 17 as an orange-red liquid (270 mg, yield: 77%).

The preparation method of embodiment 3 :

Compound 17 (270 mg, 0.35 mmol), compound 14 (329 mg, 0.35 mmol), tris(2-furyl)phosphine (17 mg, 0.06 mmol) were dissolved in Pd2(dba) ₃ ( ₁₃ mg, 0.01 mmol) under nitrogen in anhydrous chlorobenzene (11 mL). Next, the mixture was heated under reflux with stirring for 2 hours. After the reaction was completed, the temperature was lowered to room temperature and poured into methanol to precipitate a solid. Next, the precipitate was collected by filtration and the solid was subjected to Soxhlet extraction with methanol, acetone and chloroform in this order. Finally, the chloroform solution was poured into methanol for reprecipitation, and the precipitate was collected by filtration, and dried in vacuum to obtain the conjugated polymer Example 3 (391 mg, yield: 89%).

<Example 4>

Conjugated polymers

The repeating units contained in the conjugated polymer of Example 4 and the preparation method are as follows.

Example 4

The preparation method of compound 18 :

Compound 15 (890 mg, 1.81 mmol), potassium carbonate (300 mg, 2.17 mmol) were dissolved in dimethylformamide (16 mL), and heated to 80° C. and stirred for 10 minutes. Next, 2-ethyliodohexane (0.65 mL, 2.7 mmol) was dissolved in dimethylformamide (4 mL). At 80°C, it was slowly added dropwise to the reaction flask and heating was continued for 2 hours. After the reaction was completed, the temperature was lowered to room temperature. Next, extract with petroleum ether and water. The organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried in vacuo to obtain compound 18 (1.0 g, yield: 91%) as an orange-yellow liquid.

The preparation method of compound 19 :

Compound 18 (1.0 g, 1.66 mmol) and N-bromosuccinimide (606 mg, 3.40 mmol) were dissolved in tetrahydrofuran (20 mL). Next, it heated to 45 degreeC and stirred for 1 hour. After confirming the completion of the reaction, the temperature was lowered to room temperature. Next, extract with petroleum ether and water. Finally, the organic layer was dried over anhydrous magnesium sulfate. After concentration, the crude product was purified by silica gel column chromatography (petroleum ether/dichloromethane), and then dried in vacuo to obtain orange-red liquid compound 19 (824 mg, yield: 65%).

Example 4

The preparation method of embodiment 4 :

Compound 19 (250 mg, 0.33 mmol), compound 13 (297 mg, 0.33 mmol), tris(2-furyl)phosphine (16 mg, 0.05 mmol) were dissolved in Pd2(dba) ₃ ( ₁₂ mg, 0.01 mmol) under nitrogen in anhydrous chlorobenzene (18 mL). Next, the mixture was heated under reflux with stirring for 2 hours. After the reaction was completed, the temperature was lowered to room temperature and poured into methanol to precipitate a solid. Next, the precipitate was collected by filtration and the solid was subjected to Soxhlet extraction with methanol, acetone and chloroform in this order. Finally, the chloroform solution was poured into methanol for reprecipitation, and the precipitate was collected by filtration, and vacuum-dried to obtain the conjugated polymer Example 4 (350 mg, yield: 88%).

<Example 5>

Conjugated polymers

The repeating units contained in the conjugated polymer of Example 5 and the preparation method are shown below.

Example 5

The preparation method of embodiment 5 :

Compound 19 (250 mg, 0.33 mmol), compound 14 (309 mg, 0.33 mmol), tris(2-furyl)phosphine (16 mg, 0.05 mmol) were dissolved in Pd2(dba) ₃ ( ₁₂ mg, 0.01 mmol) under nitrogen in anhydrous chlorobenzene (18 mL). Next, the mixture was heated under reflux with stirring for 2 hours. After the reaction was completed, the temperature was lowered to room temperature and poured into methanol to precipitate a solid. Next, the precipitate was collected by filtration and the solid was subjected to Soxhlet extraction with methanol, acetone and chloroform in this order. Finally, the chloroform solution was poured into methanol for reprecipitation, and the precipitate was collected by filtration, and dried in vacuum to obtain the conjugated polymer Example 5 (370 mg, yield: 90%).

<Photophysical Properties of Conjugated Polymers>

FIG. 1 illustrates the UV-Vis absorption spectra of the conjugated polymers of Examples 3 to 5 in liquid state (soln.) and solid state (film).

It can be found from Fig. 1 that the absorption of solid state and liquid state has obvious red shift phenomenon. It indicates that the conjugated polymer with electron-deficient heterocyclic quinoxaline and imide central structure of the present invention can increase the stacking of molecules.

<Organic photovoltaic cell structure>

Referring to FIG. 2 , the first structure of the organic photovoltaic element of the present invention includes a substrate 70 , a negative electrode 80 stacked on the substrate 70 , an electron transport layer 91 stacked on the negative electrode 80 , and an electron transport layer stacked on the electron transport layer. An active layer 92 above 91 , a hole transport layer 93 laminated above the active layer 92 , and a positive electrode 100 laminated above the hole transport layer 93 .

3, the second structure of the organic photovoltaic element of the present invention includes a substrate 70, a positive electrode 100 stacked on the substrate 70, a hole transport layer 93 stacked on the positive electrode 100, a hole stacked on the hole An active layer 92 above the transport layer 93 , an electron transport layer 91 laminated above the active layer 92 , and a negative electrode 80 laminated above the electron transport layer 91 .

<Application example 1~3>

Organic photovoltaic cells

The organic photovoltaic cells of Application Examples 1 to 3 (see FIG. 2 for the structure) were prepared according to the materials shown in Table 1 below and the following methods.

Before preparing the organic photovoltaic element, the patterned ITO glass substrate (12Ω/□) was sequentially cleaned with detergent, deionized water, acetone and isopropanol in an ultrasonic vibration tank for 10 minutes respectively. After the ITO glass substrate was cleaned by ultrasonic vibration, the surface was treated in a UV-ozone cleaning machine for 30 minutes. The glass substrate is the aforementioned substrate 70 , and the ITO is the aforementioned negative electrode 80 .

The zinc acetate [Zn(OAc) ₂ ] solution was spin-coated on an ITO glass substrate, and baked at 170° C. for 30 minutes to form a ZnO layer (zinc oxide layer), which is the aforementioned electron transport layer 91 .

The conjugated polymer listed in Table 1 was used as the electron donor material, and mixed with the non-fullerene electron acceptor material in a weight ratio of 1:1.2, and then mixed with o-xylene (chlorine-free solvent) Prepare the active layer solution. Among them, the structure of the non-fullerene electron acceptor material is shown below.

The active layer solution was spin-coated on the aforementioned ZnO layer (electron transport layer 91 ), and baked under nitrogen at 120° C. for 10 minutes to form the aforementioned active layer 92 on the ZnO layer (electron transport layer 91 ).

It is sent into a vacuum chamber, and molybdenum trioxide (MoO ₃ ) metal oxide (about 4 nm) is heated and deposited to form the aforementioned hole transport layer 93 on the active layer 92 .

Finally, after heating and depositing Ag metal (about 100 nm) as the aforementioned positive electrode 100, an organic photovoltaic element is obtained.

<Electrical analysis of organic photovoltaic elements>

The measurement area of the organic photovoltaic elements of Application Examples 1 to 3 is defined as 0.04 cm ² through the metal mask. This electrical analysis uses a multi-function power meter (manufacturer's model: Keithley 2400) as the power supply and is controlled by a Lab-View computer program. The organic photovoltaic cells were irradiated with simulated sunlight from a solar light source simulator (manufacturer's model: SAN-EI XES-40S3) and recorded with a computer program. The illuminance of the aforementioned simulated sunlight is 100 mW/cm ² (AM1.5G).

<Power Conversion Efficiency (PCE) Analysis of Organic Photovoltaic Elements>

Electron-donor materials (conjugated polymers) used in the organic photovoltaic elements of Application Examples 1-3, and their open-circuit voltage (open voltage; V _oc ), short-circuit current (short-circuit current; J _sc ), fill factor ( The fill factor; FF) and the energy conversion efficiency (PCE) are summarized in Table 2 below, respectively. The power conversion efficiency (PCE) is obtained by dividing the product of the three values of open circuit voltage, short circuit current and fill factor by the irradiated simulated sunlight energy, and the higher the value, the better.

It can be seen from the results in Table 1 that the organic photovoltaic elements of Application Examples 1 to 3 all have high energy conversion efficiency (PCE). It is particularly worth mentioning that, compared with the central structure of the conjugated polymer used, the quinoxaline has a branched chain alkyl group (that is, R ² is -OR ⁷ and R ⁷ is a C ₄ ~C ₃₀ branched chain alkyl group). ) application examples 2~3, the quinoxaline of the central structure has a straight chain alkyl group (that is, R ² is -OR ⁷ and R ⁷ is a C ₄ ~C ₃₀ straight chain alkyl group) Application example 1 will be better The power conversion efficiency (PCE).

In summary, because the conjugated polymer of the present invention has a wide energy gap and has electron-deficient heterocyclic quinoxaline and imide central structures, it has good stackability, and further And can strengthen its electron transfer ability when it is used as electron donor material. Therefore, the organic photovoltaic element using the conjugated polymer of the present invention as the electron donor material will have higher energy conversion efficiency (PCE).

In addition, since the conjugated polymer of the present invention has a certain solubility for chlorine-free solvents. Therefore, when the conjugated polymer of the present invention is used as the electron donor material and the non-fullerene electron acceptor material, a relatively environmentally friendly chlorine-free solvent can be used to dissolve it in the process, and it is suitable for large-area coating to facilitate The subsequent coating process is carried out.

However, the above are only examples of the present invention, and should not limit the scope of the present invention. Any simple equivalent changes and modifications made according to the scope of the application for patent of the present invention and the content of the patent specification are still within the scope of the present invention. within the scope of the invention patent.

70: Substrate

80: negative pole

91: electron transport layer

92: Active layer

93: hole transport layer

100: positive

Claims (10)

A conjugated polymer, comprising the repeating unit shown in the following formula (I):

Wherein, p and q are respectively 0, 1 or 2; R ¹ and R ² are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ , - Si(R ¹⁰ ) ₃ or heteroaryl, wherein R ¹ and R ² are different from each other; R ³ is H, R ⁶ , aryl or heteroaryl; R ⁶ to R ¹⁰ are respectively unsubstituted or at least C ₄ ~ C ₃₀ linear, branched or cyclic alkyl substituted by one R ¹⁹ , C ₄ ~ C ₃₀ alkenyl substituted by at least one R ¹⁹ , or unsubstituted or by at least one R ¹⁹ Substituted C ₄ -C ₃₀ alkynyl; R ¹⁹ is halogen, -CN or -SiR ²⁰ R ²¹ R ²² ; R ²⁰ to R ²² are respectively C ₁ -C ₃₀ alkyl; and Ar ¹ to Ar ³ are respectively subordinate Aryl or heteroarylene. The conjugated polymer of claim 1, wherein Ar ¹ is

, and R ⁴ and R ⁵ are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ , -Si(R ¹⁰ ) ₃ , aryl or hetero Aryl. The conjugated polymer of claim 2, wherein the aryl group in R ³ to R ⁵ is

, and n ₁ is 1, 2, 3, 4 or 5; and R ¹¹ is H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ⁹ or -Si (R ¹⁰ ) ₃ . The conjugated polymer of claim 2, wherein the heteroaryl groups in R ¹ to R ⁵ are

, and n ₂ is 1, 2, 3, 4 or 5; and R ¹² to R ¹⁴ are H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR, respectively ⁹ or -Si(R ¹⁰ ) ₃ . The conjugated polymer according to claim 4, wherein R ¹ and R ² are H,

or -OR ⁷ , and at least one of R ¹ and R ² is

or -OR ⁷ . The conjugated polymer according to claim 4, wherein R ⁴ and R ⁵ are respectively

. The conjugated polymer according to claim 2, wherein Ar ² and Ar ³ are respectively

or

, and n ₃ and n ₄ are respectively 1, 2 or 3; and R ¹⁵ to R ¹⁸ are respectively H, F, Cl, R ⁶ , -CN, -OR ⁷ , -SR ⁸ , -C(=O)OR ^9. Aryl or heteroaryl. An organic photovoltaic element comprising the conjugated polymer of claim 1. The organic photovoltaic element according to claim 8, wherein the organic photovoltaic element comprises a substrate, a negative electrode laminated on the substrate, an electron transport layer laminated on the negative electrode, and an electron transport layer laminated on the electron transport layer. An active layer, a hole transport layer laminated on the active layer, and a positive electrode laminated on the hole transport layer, and the active layer includes the conjugated polymer. The organic photovoltaic element of claim 8, wherein the organic photovoltaic element comprises a substrate, a positive electrode layered on the substrate, a hole transport layer layered on the positive electrode, a hole transport layer layered on the hole transport layer an active layer above the layer, an electron transport layer laminated above the active layer, and a negative electrode laminated above the electron transport layer, and the active layer includes the conjugated polymer.

Images