CN103923106A - Low-energy-gap and broad-absorption conjugated polymer and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of organic semiconductor preparation, specifically a conjugated monomer polymer with low energy gap and wide absorption that can be applied to solar cells and a preparation method thereof. The technical scheme of the invention is based on 3,4-ethylenedioxide 2,1,3-benzothiadiazole (BT) is an electron-accepting unit, and a new type D-A conjugated monomer EDOTBT is obtained from EDOT and BT by Heck coupling reaction. The body has a strong electron push-pull effect, and the above-mentioned D-A conjugated monomers can be used to prepare new high-molecular-weight polymers through Heck coupling reaction or Suzuki coupling reaction. These polymers have low band gap, wide absorption, high photoconversion efficiency and The good film-forming property can be used as the active layer of the polymer solar cell, can effectively improve the energy conversion efficiency of the polymer solar cell, and is suitable for popularization and application in the polymer solar cell.

Description

A kind of conjugated polymer with low energy gap wide absorption and preparation method thereof

technical field

The invention relates to the technical field of organic semiconductor preparation, in particular to a conjugated polymer with low energy gap and wide absorption applicable to solar cells and a preparation method thereof.

Background technique

In recent years, due to the prominent advantages of polymer solar cells (PSCs), such as low production cost, convenient preparation, safety, environmental protection, and sustainable development, the research community has gradually broadened and deepened the research on polymer solar cells. In the prior art, the research focus of organic photovoltaic cells mainly focuses on the problem of photoelectric conversion efficiency. In order to improve the photoelectric conversion efficiency of organic photovoltaic cells, researchers generally require that there is a gap between the absorption spectrum of organic photovoltaic cells and the solar light emission spectrum. These low-energy bandgap polymer materials generally have the following characteristics: (1) narrow energy bandwidth absorption, which can capture more photons and increase short-circuit current; (2) crystalline structure, which is easy to obtain High photoelectric conversion efficiency; (3) lower HOMO energy level, which can increase the open circuit voltage (Voc) of polymer devices; (4) moderate LUMO energy level, which facilitates effective charge transfer between fullerenes and improves Hole mobility and filling factor, one of the most effective ways to meet the above requirements is to introduce electron-donor units (Donor) and electron-acceptor units (Acceptor) into the polymer main chain to form D-A-type polymers. Intramolecular charge transfer will occur between the electron-donating unit and the electron-accepting ability of the electron-accepting unit will affect the electronic structure and performance of the D-A polymer; in addition, the D-A polymer can be selected by different electron-donating groups Groups and electron-accepting groups regulate energy bands, energy levels, and charge mobility.

The research results of relevant low-gap polymers in the prior art are as follows: Jiang J M et al. (Macromolecules, 2011, 44(23): 9155-9163.) synthesized new low-energy band crystalline polymers PTHBO, PBTTBO and PTTTBO , this paper uses electron-rich thiophene (TH), 2,2-bisthiophene (BT) and thienylthiophene (TT) as the electron-pushing unit, and electron-deficient 2,1,3-benzooxadiazole as the pulling unit. Electronic unit, the resulting polymer exhibits effective charge transfer with fullerenes to balance the energy of the polymer, lowering the HOMO energy level of the polymer, while exhibiting good thermal stability, high crystallinity and wide absorption range . Zhang M et al. (Chemistry of Materials, 2011, 23(18): 4264-4270.) prepared four types of D-A polymers, using four dodecyl-substituted benzodithiophene (IDT) as electron pushers The unit is based on four different groups of bisthienylthiazole (BTz), bisthienylthiazolylthiazole (TTz), bisthienyltetraazepine (TZ), and bisthienylbenzothiadiazole (DTBT) Electronic unit, the synthesized copolymers are PIDT-BTz, PIDT-TTz, PIDT-TZ and PIDT-DTBT, respectively. Wang M, LiC, Lv A, et al. (Polymer, 2012, 53(2): 324-332.) synthesized polymers with triphenylamine as the electron donor and thienobenzothiadiazole as the electron-withdrawing Group of D-A type copolymers.

Contents of the invention

The object of the present invention is to provide a D-A type conjugated monomer with strong electron push-pull effect and its preparation method, thus the preparation of D-A type conjugated monomer has low band gap, wide absorption, and high photoconversion Characterization of Efficiency and Good Film Formation High Molecular Weight New Polymers and Process for Making Active Layers of Solar Cells from These Polymers.

The technical solution adopted by the present invention to solve the technical problem is: a D-A type conjugated monomer with low energy gap and wide absorption, the structural formula of the monomer is:

Wherein, R is H, Cl, Br or I.

A kind of preparation method of the D-A type conjugated monomer of low energy gap wide absorption, has the following steps:

(1) Add 3,4-ethylenedioxythiophene, 4,7-dibromo-2,1,3-benzothiadiazole, catalyst, ligand, weak base into the reaction vessel, and then add Solvent, vacuumize the reactor and fill it with nitrogen, heat to 90°C, and react for 12-48h under stirring;

(2) After the reaction is over, pour the resulting product into distilled water and use dichloromethane to extract and separate liquids, wash three times, dry over anhydrous magnesium sulfate, and pass through a column (wherein the solid phase is basic alumina, and the mobile phase is toluene: two Chloromethane=1:1), precipitated with methanol 3-5 times, and vacuum-dried to obtain a solid product that is the target product 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole ( H-EDOTBT-H);

(3) Add N-halosuccinimide, ice Acetic acid, then add a solvent to the container, and react for 24-48h under the condition of avoiding light and stirring in an ice bath;

(4) After the reaction is finished, dissolve it with 1-methyl-2-pyrrolidone after rotary evaporation to dryness, precipitate with methanol, filter and recover the precipitate, and dry it in vacuum to obtain solid products that are the target products Cl-EDOTBT-Cl, Br-EDOTBT-Cl, Br-EDOTBT- Br or I-EDOTBT-I;

Among them, 3,4-ethylenedioxythiophene is shown in the following structural formula I: 4,7-dibromo-2,1,3-benzothiadiazole is shown in the following structural formula II, and the D-A type conjugated mono The body H-EDOTBT-H is shown in the following structural formula III, the N-halogenated succinimide is shown in the following structural formula IV, and the D-A type conjugated monomer Br-EDOTBT-Br is shown in the following structural formula V.

IV, where A=Cl, Br, I, V.

Further, in the step (1), the feed ratio of 3,4-ethylenedioxythiophene and 4,7-dibromo-2,1,3-benzothiadiazole is (2+x ₁ ):1 , _x1 is 0.1-0.5;

The catalyst is a palladium catalyst, and the molar ratio of the total amount of 3,4-ethylenedioxythiophene and 4,7-dibromo-2,1,3-benzothiadiazole to the catalyst is 1:0.003-0.1;

The ligand is one of tetrabutylammonium bromide, tricyclohexylphosphine fluoroborate, tricyclohexylphosphine, trisulfenylphosphine, triphenylphosphine or triethylenediamine, and the mole of ligand and catalyst The ratio is 4-12:1;

The weak base is potassium carbonate, potassium acetate, tetramethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrabutylammonium hydroxide aqueous solution with a mass fraction of 5-50%, and tetraethylammonium hydroxide aqueous solution with a mass fraction of 5-50%. Ammonium hydroxide aqueous solution, tetrapropyl ammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrahexyl ammonium hydroxide aqueous solution with a mass fraction of 5-50% or tetraoctyl ammonium hydroxide with a mass fraction of 5-50% One of the aqueous solutions, the molar ratio of alkali to catalyst is 30-80:1;

The solvent is N,N-dimethylformamide or N,N-dimethylacetamide, the amount of which is 3,4-ethylenedioxythiophene and 4,7-dibromo-2,1,3-benzo The molar concentration of the total amount of thiadiazole is 0.1-0.5mol/L.

Further preferably, the catalyst is one of Pd(OA _C ) ₂ , PdCl ₂ (dppf) or Pd(PPh ₃ ) ₄ , 3,4-ethylenedioxythiophene and 4,7-dibromo-2, The optimal molar ratio of the total amount of 1,3-benzothiadiazole to the catalyst is 1:0.035.

Further, in the step (3), the feeding of 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole (H-EDOTBT-H) and N-halosuccinimide The ratio is 1:(2+x ₂ ), and x ₂ is 0.1-5;

The molar ratio of glacial acetic acid to 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole (H-EDOTBT-H) is 9:1;

The solvent is chloroform or tetrahydrofuran, and its dosage is 4,7-bis(3,4-ethylenedioxythiophene)-2,1,3-benzothiadiazole (H-EDOTBT-H) and N-halogenated succinate The molar concentration of the total amount of imide NBS is 0.1-5mol/L.

A polymer of D-A conjugated monomer with low energy gap and wide absorption, the structural formula of the polymer is:

The number average molecular weight of the polymer is 1000-100000;

Wherein, n is 1-10; X is 0.05-0.95; R ₃ is H, Br or

Ar is or One of them, R ₁ and R ₂ are H or (CH ₂ )zCH ₃ , wherein the number of z is 1-11.

A method for preparing a polymer containing D-A type conjugated monomers with low energy gap and wide absorption can be synthesized by two coupling reactions, one is through Heck coupling reaction, and the other is through Suzuki coupling reaction.

Synthesis of D-A type low energy gap conjugated polymers by Heck coupling reaction has the following steps:

(1) Add 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (H-EDOTBT-H), 2,7-dibromofluorene or 1 into the reaction vessel, One of 4-dibromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine, catalyst, ligand, weak base, and then add solvent to the container , vacuumize the reaction vessel, fill it with nitrogen, heat to 95°C, and react for 12-48h under stirring conditions;

(2) After the reaction is over, the resulting product is successively added to methanol for precipitation, filtered to recover the precipitate, dichloromethane to dissolve the precipitate, passed through the column (wherein the solid phase is silica gel, and the mobile phase is dichloromethane), evaporated and concentrated by a rotary evaporator, and then Add methanol to precipitate, filter to recover the precipitate, vacuum dry, and finally obtain a solid product that is the target product;

Among them, 2,7-dibromofluorene, 1,4-dibromobenzene, 4,4'-dibromo-1,1'-biphenyl, 4,4'-dibromotriphenylamine are as follows VI, VII, As shown in the structural formulas of VIII and IX, wherein R ₁ and R ₂ are H or (CH ₂ )zCH ₃ , wherein the number of z is 1-11,

Further, in the step (1), 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (H-EDOTBT-H) and 2,7-dibromofluorene or The molar feeding ratio of one of 1,4-dibromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine is 0.5-1:1;

The catalyst is a palladium catalyst, 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (H-EDOTBT-H) and 2,7-dibromofluorene or 1,4-bis The molar ratio of the total amount of one of bromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine to the catalyst is 1:0.003-0.1;

The ligand is one of tetrabutylammonium bromide, tricyclohexylphosphine fluoroborate, tricyclohexylphosphine, trisulfenylphosphine, triphenylphosphine or triethylenediamine, and the mole of ligand and catalyst The ratio is 4-12:1;

The weak base is potassium carbonate, potassium acetate, tetramethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrabutylammonium hydroxide aqueous solution with a mass fraction of 5-50%, and tetraethylammonium hydroxide aqueous solution with a mass fraction of 5-50%. Ammonium hydroxide aqueous solution, tetrapropyl ammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrahexyl ammonium hydroxide aqueous solution with a mass fraction of 5-50% or tetraoctyl ammonium hydroxide with a mass fraction of 5-50% A kind of aqueous solution, alkali and 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and 2,7-dibromofluorene or 1,4-dibromobenzene or 4 , the molar ratio of the total amount of one of 4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine is 4-12:1;

Solvent is N, N-dimethylformamide, N, N-dimethylacetamide, and its consumption is 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and Moles of the total amount of one of 2,7-dibromofluorene or 1,4-dibromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine The concentration is 0.1-0.5mol/L.

Further preferably, the catalyst is one of Pd(OA _C ) ₂ , PdCl ₂ (dppf) or Pd(PPh ₃ ) ₄ , 4,7-bis(3,4-ethylenedioxythiophene)-benzo Thiadiazole monomer (H-EDOTBT-H) and 2,7-dibromofluorene or 1,4-dibromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4'- The optimum ratio of the total amount of one of the dibromotriphenylamines to the catalyst is 1:0.04.

A kind of preparation method of the polymkeric substance that synthesizes the conjugated monomer of D-A type low energy gap wide absorption by Suzuki coupling reaction, has following steps:

(1) Add brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (Br-EDOTBT-Br), fluorene or benzene or biphenyl in the reaction vessel Or diboronic ester of triphenylamine, catalyst, ligand, weak base, then add solvent into the container, vacuumize the reaction container, fill it with nitrogen, heat to 95°C, and react for 12-48h under stirring; then add phenylboronic acid to react 2 hours, finally add bromobenzene to react for 2 hours;

(2) After the reaction is over, the resulting product is successively added to methanol for precipitation, filtered to recover the precipitate, dichloromethane to dissolve the precipitate, passed through the column (wherein the solid phase is silica gel, and the mobile phase is dichloromethane), evaporated and concentrated by a rotary evaporator, and then Add methanol to precipitate, filter to recover the precipitate, vacuum dry, and finally obtain a solid product that is the target product;

Among them, the diboronic acid ester of fluorene or benzene or biphenyl or triphenylamine is specifically: 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborane-di base)-9,9-difluorene, 1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-benzene, 4,4'-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-1,1'-biphenyl and 4,4'-bis(4,4, 5,5-Tetramethyl-1,3,2-dioxaborolane-diyl)triphenylamine, its structural formula is shown in VI, VII, VIII, IX, R ₁ and R ₂ are H or (CH ₂ )zCH ₃ , wherein the number of z is 1-11,

Further, in the step (1), the brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (Br-EDOTBT-Br), fluorene or benzene or The feeding ratio of biphenyl or triphenylamine diboronic acid ester is 1:1;

The catalyst is a palladium catalyst, brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (Br-EDOTBT-Br) and diboron of fluorene or benzene or biphenyl The molar ratio of the total amount of acid ester to the catalyst is 1:0.003-0.1;

The ligand is one of tricyclohexylphosphine fluoroborate, tricyclohexylphosphine, tri-tert-butylphosphine, triphenylphosphine or triethylenediamine, and the molar ratio of ligand to catalyst is 4-12:1 ;

The weak base is a tetramethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, a tetrabutylammonium hydroxide aqueous solution with a mass fraction of 5-50%, a tetraethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, and a mass fraction of Fraction is 5-50% tetrapropyl ammonium hydroxide aqueous solution, mass fraction is 5-50% tetrahexyl ammonium hydroxide aqueous solution, mass fraction is 5-50% tetraoctyl ammonium hydroxide aqueous solution, potassium acetate or carbonic acid One of potassium, weak base and brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (Br-EDOTBT-Br) and fluorene or benzene or bis The mol ratio of the diboronic ester total amount of benzene or triphenylamine is 4-12:1;

The solvent is one of benzene, toluene or xylene, and its dosage is brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (Br-EDOTBT-Br ) and the total molar concentration of diboronic esters of fluorene or benzene or biphenyl or triphenylamine are 0.1-0.5mol/L;

The molar ratio of the amount of phenylboronic acid to brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer (Br-EDOTBT-Br) is 1:1; The molar ratio of the amount of benzene to the diboronic ester of fluorene or benzene or biphenyl or triphenylamine is 1:1.

Further preferably, the catalyst is one of Pd(OA _C ) ₂ , PdCl ₂ (dppf) or Pd(PPh ₃ ) ₄ , and brominated 4,7-bis(3,4-ethylenedioxythiophene )-benzothiadiazole monomer (Br-EDOTBT-Br) and the total amount of diboronic acid ester of fluorene or benzene or biphenyl and the optimal ratio of the catalyst is 1:0.04.

The polymer of the conjugated monomer with low energy gap and wide absorption obtained by adopting the technical scheme of the present invention is applied to the preparation of organic solar cells, and the battery structure is: anode ITO/hole transport layer/active layer/(electron transport layer)/cathode Al; the specific preparation method is as follows:

(1) Clean the glass substrate containing ITO, spin-coat PEDOT/PSS solution on ITO, anneal after spin-coating and drying to obtain a hole transport layer;

(2) The low-energy-gap conjugated polymer obtained in the present invention and tetrabutyl titanate (TBTT) or [6,6]-phenyl C ₆₁ butyric acid methyl ester (PCBM) blend are dissolved in chloroform solvent and spin Coated on the hole transport layer, spin-coated and annealed to obtain the active layer; the mass ratio of conjugated polymer to TBTT or PCBM is 1:1-20;

(3) Evaporate a layer of Al with a thickness of 100 nm on the obtained structure under vacuum condition (1×10 ⁻⁴ Pa).

The spin coating described in step (1) and step (2) is divided into two steps, and the first step rotating speed is 750r/min, and the time is 10s, and the second step rotating speed is 3000-4500r/min, and the time is 25-30s, The spin coating environment is air or nitrogen; the annealing temperature is 130-200°C, the annealing time is 10-30min, and the annealing environment is air.

Beneficial effects: the present invention uses 3,4-ethylenedioxythiophene (EDOT) as the electron-donating unit, 2,1,3-benzothiadiazole (BT) as the electron-accepting unit, and adopts Heck coupling reaction to form EDOT and BT A novel D-A type conjugated monomer 4,7-bis(3,4-ethylenedioxythiophene)-2,1,3-benzothiadiazole (EDOTBT) was prepared, and the D-A type conjugated monomer has relatively Strong electron push-pull effect, high molecular weight new polymers can be prepared from the above-mentioned D-A type conjugated monomers through Heck coupling reaction or Suzuki coupling reaction, these polymers have low band gap, wide absorption, high light conversion efficiency and good The film-forming feature can be used as the active layer of the polymer solar cell, can effectively improve the energy conversion efficiency (PCE) of the polymer solar cell, and is suitable for popularization and application in the polymer solar cell.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is further described;

Fig. 1 is the ¹ HNMR of the conjugated monomer 4,7-bis(3,4-ethylenedioxythiophene)-2,1,3-benzothiadiazole H-EDOTBT-H in Example 1 of the present invention;

Figure 2 is Br-EDOTBT after bromination of DA-type conjugated monomer 4,7-bis(3,4-ethylenedioxythiophene)-2,1,3-benzothiadiazole in Example 2 of the present invention - ¹ H NMR of Br;

Fig. 3 is the ¹ HNMR of polymer PF6EDOTBT in embodiment 3 of the present invention;

Fig. 4 is the ultraviolet absorption figure of polymer PF6EDOTBT in the embodiment of the present invention 3;

Fig. 5 is an ultraviolet absorption diagram of polymer PF8EDOTBT in Example 4 of the present invention.

Detailed ways

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited to this example. Embodiment one

Synthesis of 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole conjugated monomer H-EDOTBT-H:

Reaction steps:

In a 100ml three-necked flask equipped with a thermometer and a stirring bar, quantitatively add 0.147g (0.5mmol) of 4,7-dibromo-2,1,3-benzothiadiazole, 0.142g (1mmol) of 3, 4 Ethylenedioxythiophene, 0.0118g (0.0525mmol) of Pd(OA _C ) ₂ , 0.498g (1.5mmol) of tetrabutylammonium bromide TBAB, 0.3628g (2.625mmol) of potassium carbonate K ₂ CO ₃ , 8 ml of N,N-dimethylformamide DMF. Mix them evenly, and react at 95° C. for 12 h under a nitrogen atmosphere to stop the reaction. After the reaction was finished, the resulting product was poured into distilled water and extracted and separated with methyl chloride, washed with water three times, dried over anhydrous magnesium sulfate, and passed through a column (wherein the solid phase was basic alumina, and the mobile phase was toluene:dichloromethane=1 : 1), precipitated with methanol several times, and vacuum-dried to finally obtain a solid product which is the target product. Vacuum-dried at 80°C for 24 hours, the yield was 40%, and ¹ of the product 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole conjugated monomer H-EDOTBT-H See Figure 1 for HNMR.

Embodiment two

Synthesis of D-A conjugated monomer Br-EDOTBT-Br:

Reaction steps:

In a 100ml three-necked flask equipped with a thermometer and a stirring bar, quantitatively add 0.208g (0.5mmol) of 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole H-EDOTBT-H , 0.1780 g (1 mmol) of N-bromosuccinimide, 0.27 g (4.5 mmol) of acetic acid, and 12 ml of chloroform. The reaction was carried out for more than 24 hours under stirring in an ice bath in the dark. After the reaction, methanol was precipitated. The precipitate was recovered by filtration and dried in vacuum. Finally, a solid product was obtained, which was the target product. Vacuum drying at 100° C. for 24 h gave a yield of 80%. Fig. 2 is the ¹ HNMR of the DA-type conjugated monomer Br-EDOTBT-Br synthesized in this example.

Embodiment three

Copolymer PF6EDOTBT of D-A type conjugated monomer H-EDOTBT-H and 9,9-dihexylfluorene:

Aggregation steps:

In a 100ml three-necked flask equipped with a thermometer and a stirrer, quantitatively add 0.2496g (0.6mmol) of DA-type conjugated monomer H-EDOTBT-H, 0.2952g (0.6mmol) of 2,7-dibromo9,9 - Dihexylfluorene, 0.0008 g (0.0036 mmol) of Pd(OA _C ) ₂ , 0.0048 g (0.0144 mmol) of tetrabutylammonium bromide TBAB, 0.6634 g (4.8 mmol) of potassium carbonate K ₂ CO ₃ and 12 ml of N,N - A mixed solvent of dimethylformamide DMF. Mix them evenly, react at 90° C. for 12 h under a nitrogen atmosphere, and then stop the reaction. After the reaction, precipitate with methanol, filter and recover the precipitate, then dissolve it with dichloromethane and pass it through the column (where the solid phase is silica gel, and the mobile phase is dichloromethane), concentrate with a rotary evaporator, then add methanol to precipitate, filter and recover the precipitate, and vacuum dry treatment, the final solid product is the target product. It was dried in a vacuum oven at 80°C for 24 hours, and the yield was 54.2%. Fig. 3 is the ¹ HNMR of the polymer PF6EDOTBT synthesized in this example, and Fig. 4 is the ultraviolet absorption diagram of the polymer PF6EDOTBT.

Embodiment four

Copolymer PF8EDOTBT of D-A type conjugated monomer Br-EDOTBT-Br and 9,9-dioctylfluorene:

Aggregation steps:

In a 100ml three-necked flask equipped with a thermometer and a stirrer, quantitatively add 0.3444g (0.6mmol) DA-type conjugated monomer Br-EDOTBT-Br, 0.38556g (0.6mmol), 2,7-bis(4,4 , 5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-9,9-dioctylfluorene, 0.004g (0.018mmol) of Pd(OA _C ) ₂ , 0.022g (0.20mmol) triethylenediamine DABCO, 8ml of a mixed solvent with a mass fraction of 25% Et4NOH and 10ml of toluene, mix them uniformly, react at 90°C for 12h under a nitrogen atmosphere, and then stop the reaction. Then add 0.0612g (0.5mmol) phenylboronic acid to react for 2h, and finally add 0.078g (0.5mmol) bromobenzene to react for 2h. Precipitate with methanol, recover the precipitate by filtration, dissolve it with dichloromethane and pass it through the column (where the solid phase is silica gel, and the mobile phase is dichloromethane), concentrate with a rotary evaporator, add methanol to precipitate, recover the precipitate by filtration, and dry it in vacuum. The solid product obtained is the target product. It was dried in a vacuum oven at 80° C. for 24 hours, and the yield was 58.4%. FIG. 5 is the ultraviolet absorption diagram of the target product PF8EDOTBT.

Table 1 is the optical property data of embodiment three and embodiment four gained copolymers

Embodiment five

Copolymer of D-A conjugated monomer H-EDOTBT-H and biphenyl:

Aggregation steps:

In a 100ml three-necked flask equipped with a thermometer and a stirrer, quantitatively add 0.2496g (0.6mmol) DA-type conjugated monomer H-EDOTBT-H, 0.1872g (0.6mmol), 4,4'-dibromo-1 , 1'-biphenyl, 0.0094g (0.042mmol) of Pd(OA _C ) ₂ , 0.0619g (0.168mmol) tricyclohexylphosphine fluoroborate, 8ml mass fraction of 25% tetrapropylammonium hydroxide aqueous solution and 10ml of N, N-dimethylacetamide DMA mixed solvent. Mix them evenly, react at 90° C. for 12 h under a nitrogen atmosphere, and then stop the reaction. After the reaction, precipitate methanol, filter and recover the precipitate, then dissolve it with dichloromethane and pass it through the column (wherein the solid phase is silica gel, and the mobile phase is dichloromethane), concentrate with a rotary evaporator, then add methanol to precipitate, filter and recover the precipitate, and vacuum dry After treatment, a solid product is finally obtained, which is the target product, and dried in a vacuum oven at 80° C. for 24 hours, with a yield of 53.4%.

Embodiment six

Copolymer of D-A conjugated monomer Br-EDOTBT-Br and benzene:

Aggregation steps:

In a 100ml three-neck flask equipped with a thermometer and a stirrer, quantitatively add 0.3444g (0.6mmol) DA type conjugated monomer Br-EDOTBT-Br, 0.198g (0.6mmol), 1,4-bis(4,4 , 5,5-tetramethyl-1,3,2-dioxaborolane-diyl)-benzene, 0.028g (0.018mmol) of Pd(PPh ₃ ) ₄ , 0.022g (0.20mmol) triethylenedi Amine DABCO, 8 ml of a mixed solvent with a mass fraction of 25% Et ₄ NOH and 10 ml of toluene. Mix them evenly, react at 90° C. for 12 h under a nitrogen atmosphere, and then stop the reaction. Then add 0.0612g (0.5mmol) phenylboronic acid to react for 2h, and finally add 0.078g (0.5mmol) bromobenzene to react for 2h. Precipitate with methanol, recover the precipitate by filtration, dissolve it with dichloromethane and pass it through the column (where the solid phase is silica gel, and the mobile phase is dichloromethane), concentrate with a rotary evaporator, add methanol to precipitate, recover the precipitate by filtration, and dry it in vacuum. The solid product obtained is the target product. It was dried in a vacuum oven at 80°C for 24 hours, and the yield was 56.8%.

Embodiment seven

Copolymer of D-A conjugated monomer Br-EDOTBT-Br and triphenylamine:

Aggregation steps:

In a 100ml three-necked flask equipped with a thermometer and a stirring bar, quantitatively add 0.3444g (0.6mmol) DA type Br-EDOTBT-Br, 0.2982g (0.6mmol), 4,4'-bis(4,4,5, 5-Tetramethyl-1,3,2-dioxaborolane-diyl)triphenylamine, 0.0269 g (0.12 mmol) of Pd(OA _C ) ₂ , 0.1615 g (1.44 mmol) triethylenediamine DABCO, 12ml mass fraction is the mixed solvent of 25% tetramethylammonium hydroxide TMAOH and 30ml toluene. Mix them evenly, react at 90° C. for 12 h under a nitrogen atmosphere, and then stop the reaction. Then add 0.0612g (0.5mmol) phenylboronic acid to react for 2h, and finally add 0.078g (0.5mmol) bromobenzene to react for 2h. Precipitate with methanol, recover the precipitate by filtration, dissolve it with dichloromethane and pass it through the column (where the solid phase is silica gel, and the mobile phase is dichloromethane), concentrate with a rotary evaporator, add methanol to precipitate, recover the precipitate by filtration, and dry it in vacuum. The solid product obtained is the target product. It was dried in a vacuum oven at 80°C for 24 hours, and the yield was 56.8%.

Embodiment Eight

The prepared structure is an organic solar cell of ITO/PSS/PEDOT/PF6EDOTBT:PCBM/Al, the steps are as follows:

(1) Spread PSS/PEDOT on the cleaned ITO surface, and dry it by spin coating. 3400 rpm, spin coating for 30s, annealing in air at 120°C for 30min after completion, thickness: 100nm. That is, the organic solar cell hole transport layer is obtained;

(2) Add the copolymer PF6EDOTBT obtained in the above examples into chloroform, then add PCBM and stir evenly, filter it with a 0.45um filter head (the mass ratio of PF6EDOTBT and PCBM: 1:1), and spin coat (the first rotating speed is 750r/min , 10s; second rotation 3900r/min, 30s) on the prepared hole transport layer, annealed in air at 120° C. for 10 minutes after spin coating. The thickness is 100nm, that is, the active layer of the battery is obtained;

(3) Evaporate a layer of Al with a thickness of 100 nm on the obtained structure under vacuum condition (1×10 ⁻⁴ Pa). The test results of photovoltaic performance parameters of the obtained solar cells are shown in Table 2.

Table 2 Photovoltaic test results of solar cells

Claims (10)

1. A D-A type conjugated monomer with low energy gap and wide absorption, characterized in that: the structural formula of the monomer is: Wherein, R is H, Cl, Br or I. 2. the preparation method of the D-A type conjugated monomer of low energy gap absorption according to claim 1 is characterized in that: the preparation method has the following steps: (1) Add 3,4-ethylenedioxythiophene, 4,7-dibromo-2,1,3-benzothiadiazole, catalyst, ligand, weak base into the reaction vessel, and then add Solvent, vacuumize the reactor and fill it with nitrogen, heat to 90°C, and react for 12-48h under stirring; (2) After the reaction is over, pour the obtained product into distilled water and use dichloromethane to extract and separate liquids, wash three times with water, dry over anhydrous magnesium sulfate, pass through the column, precipitate with methanol for 3-5 times, and dry in vacuum to obtain a solid product That is the target product 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole; (3) Add N-halosuccinimide and glacial acetic acid to the target product 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole obtained above, and then add Solvent, reacted for 24-48h under the condition of stirring in an ice bath away from light; (4) After the reaction is finished, dissolve it with 1-methyl-2-pyrrolidone after rotary evaporation to dryness, precipitate with methanol, filter and recover the precipitate, and dry it in vacuum to obtain solid products that are the target products Cl-EDOTBT-Cl, Br-EDOTBT-Cl, Br-EDOTBT- Br or I-EDOTBT-I. 3. the preparation method of the DA type conjugated monomer of low energy gap wide absorption according to claim 2 is characterized in that: in described step (1), 3,4-ethylenedioxythiophene and 4,7- The feed ratio of dibromo-2,1,3-benzothiadiazole is (2+x ₁ ):1, and x ₁ is 0.1-0.5; The catalyst is a palladium catalyst, and the molar ratio of the total amount of 3,4-ethylenedioxythiophene and 4,7-dibromo-2,1,3-benzothiadiazole to the catalyst is 1:0.003-0.1; The ligand is one of tetrabutylammonium bromide, tricyclohexylphosphine fluoroborate, tricyclohexylphosphine, trisulfenylphosphine, triphenylphosphine or triethylenediamine, and the mole of ligand and catalyst The ratio is 4-12:1; The weak base is potassium carbonate, potassium acetate, tetramethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrabutylammonium hydroxide aqueous solution with a mass fraction of 5-50%, and tetraethylammonium hydroxide aqueous solution with a mass fraction of 5-50%. Ammonium hydroxide aqueous solution, tetrapropyl ammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrahexyl ammonium hydroxide aqueous solution with a mass fraction of 5-50% or tetraoctyl ammonium hydroxide with a mass fraction of 5-50% One of the aqueous solutions, the molar ratio of alkali to catalyst is 30-80:1; The solvent is N,N-dimethylformamide or N,N-dimethylacetamide, the amount of which is 3,4-ethylenedioxythiophene and 4,7-dibromo-2,1,3-benzo The molar concentration of the total amount of thiadiazole is 0.1-0.5mol/L; In the step (3), the feeding ratio of 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole and N-halosuccinimide is 1:(2+x ₂ ), _x2 is 0.1-5; The mol ratio of glacial acetic acid and 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole is 9:1; The solvent is chloroform or tetrahydrofuran, and its consumption is 4,7-bis(3,4-ethylenedioxythiophene)-2,1,3-benzothiadiazole and N-halosuccinimide NBS total amount The molar concentration is 0.1-5mol/L. 4. The preparation method of the DA-type conjugated monomer with low energy gap and wide absorption according to claim 3, characterized in that: the catalyst is Pd(OA _C ) ₂ , PdCl ₂ (dppf) or Pd(PPh ₃ ) One of ₄ , the optimal molar ratio of the total amount of 3,4-ethylenedioxythiophene and 4,7-dibromo-2,1,3-benzothiadiazole to the catalyst is 1:0.035. 5. a kind of polymkeric substance containing the D-A type conjugated monomer of low energy gap absorption described in claim 1, it is characterized in that: the structural formula of this polymkeric substance is: The number average molecular weight of the polymer is 1000-100000; Wherein, n is 1-10; X is 0.05-0.95; R ₃ is H, Br or Ar is or One of them, R ₁ and R ₂ are H or (CH ₂ )zCH ₃ , wherein the number of z is 1-11. 6. the preparation method of the polymkeric substance that contains the D-A type conjugated monomer of low energy gap wide absorption according to claim 5, it is characterized in that: this preparation method has the following steps: (1) Add 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer, 2,7-dibromofluorene or 1,4-dibromobenzene or 4 , one of 4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine, a catalyst, a ligand, a weak base, and then add a solvent to the container, and vacuumize the reaction container Fill with nitrogen, heat to 95°C, and react for 12-48h under stirring conditions; (2) After the reaction is over, the resulting product is sequentially added to methanol for precipitation, filtered to recover the precipitate, dichloromethane to dissolve the precipitate, passed through the column, evaporated and concentrated by a rotary evaporator, then added to methanol for precipitation, filtered to recover the precipitate, and vacuum-dried to finally obtain The solid product is the target product. 7. the preparation method of the polymkeric substance that contains the D-A type conjugated monomer of low energy gap wide absorption according to claim 6, it is characterized in that: in described step (1), 4,7-bis(3,4- Ethylenedioxythiophene)-benzothiadiazole monomer with 2,7-dibromofluorene or 1,4-dibromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4 A molar feed ratio of '-dibromotriphenylamine is 0.5-1:1; The catalyst is a palladium catalyst, 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and 2,7-dibromofluorene or 1,4-dibromobenzene or 4,4' - The molar ratio of the total amount of one of dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine to the catalyst is 1:0.003-0.1; The ligand is one of tetrabutylammonium bromide, tricyclohexylphosphine fluoroborate, tricyclohexylphosphine, trisulfenylphosphine, triphenylphosphine or triethylenediamine, and the mole of ligand and catalyst The ratio is 4-12:1; The weak base is potassium carbonate, potassium acetate, tetramethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrabutylammonium hydroxide aqueous solution with a mass fraction of 5-50%, and tetraethylammonium hydroxide aqueous solution with a mass fraction of 5-50%. Ammonium hydroxide aqueous solution, tetrapropyl ammonium hydroxide aqueous solution with a mass fraction of 5-50%, tetrahexyl ammonium hydroxide aqueous solution with a mass fraction of 5-50% or tetraoctyl ammonium hydroxide with a mass fraction of 5-50% A kind of aqueous solution, alkali and 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and 2,7-dibromofluorene or 1,4-dibromobenzene or 4 , the molar ratio of the total amount of one of 4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine is 4-12:1; Solvent is N, N-dimethylformamide, N, N-dimethylacetamide, and its consumption is 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and Moles of the total amount of one of 2,7-dibromofluorene or 1,4-dibromobenzene or 4,4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine The concentration is 0.1-0.5mol/L. 8. The preparation method of the polymer containing the DA type conjugated monomer with low energy gap wide absorption according to claim 7, characterized in that: the catalyst is Pd(OA _C ) ₂ , PdCl ₂ (dppf) or Pd One of (PPh ₃ ) ₄ , 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and 2,7-dibromofluorene or 1,4-dibromobenzene Or the optimal ratio of the total amount of one of 4,4'-dibromo-1,1'-biphenyl or 4,4'-dibromotriphenylamine to the catalyst is 1:0.04. 9. the preparation method of the polymkeric substance that contains the D-A type conjugated monomer of low energy gap wide absorption according to claim 5, it is characterized in that: this preparation method has the following steps: (1) Add brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer, fluorene or benzene or biphenyl or triphenylamine diboronic acid in the reaction vessel Esters, catalysts, ligands, weak bases, and then add solvent to the container, vacuumize the reaction container and fill it with nitrogen, heat to 95°C, and react for 12-48h under stirring; then add phenylboronic acid for 2h, and finally add bromobenzene Reaction 2h; (2) After the reaction is over, the resulting product is sequentially added to methanol for precipitation, filtered to recover the precipitate, dichloromethane to dissolve the precipitate, passed through the column, evaporated and concentrated by a rotary evaporator, then added to methanol for precipitation, filtered to recover the precipitate, and vacuum-dried to finally obtain The solid product is the target product. 10. the preparation method of the polymkeric substance that contains the D-A type conjugated monomer of low energy gap wide absorption according to claim 9, it is characterized in that: in described step (1), brominated 4,7-bis( The feeding ratio of 3,4-ethylenedioxythiophene)-benzothiadiazole monomer, fluorene or benzene or biphenyl or triphenylamine diboronic acid ester is 1:1; Catalyst is palladium catalyst, 4 after bromination, 7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and the diboronic acid ester total amount of fluorene or benzene or biphenyl and catalyst The molar ratio is 1:0.003-0.1; The ligand is one of tricyclohexylphosphine fluoroborate, tricyclohexylphosphine, tri-tert-butylphosphine, triphenylphosphine or triethylenediamine, and the molar ratio of ligand to catalyst is 4-12:1 ; The weak base is a tetramethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, a tetrabutylammonium hydroxide aqueous solution with a mass fraction of 5-50%, a tetraethylammonium hydroxide aqueous solution with a mass fraction of 5-50%, and a mass fraction of Fraction is 5-50% tetrapropyl ammonium hydroxide aqueous solution, mass fraction is 5-50% tetrahexyl ammonium hydroxide aqueous solution, mass fraction is 5-50% tetraoctyl ammonium hydroxide aqueous solution, potassium acetate or carbonic acid One of potassium, a weak base with brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and diboron of fluorene or benzene or biphenyl or triphenylamine The mol ratio of ester total amount is 4-12:1; The solvent is one of benzene, toluene or xylene, and its dosage is brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer and fluorene or benzene or bis The molar concentration of the total amount of diboronic acid ester of benzene or triphenylamine is 0.1-0.5mol/L; The molar ratio of the consumption of phenylboronic acid and brominated 4,7-bis(3,4-ethylenedioxythiophene)-benzothiadiazole monomer is 1:1; the consumption of bromobenzene and fluorene or benzene Or the molar ratio of biphenyl or triphenylamine diboronic acid ester is 1:1.