Conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole as well as preparation method and application of conjugated polymer photoelectric material

Abstract

The invention discloses a conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole as well as a preparation method and application of the conjugated polymer photoelectric material. The conjugated polymer containing the non-centrosymmetric benzodithiazole provided by the invention has conjugated main chain and side chain groups; wherein a conjugated main chain contains a non-centrosymmetric benzodithiazole structure and other copolymerization units D, and a side chain group is an alkyl chain R. Due to the conjugated main chain structure of the polymer, the polymer shows semiconductor characteristics and has abundant photoelectric properties; meanwhile, the group R can be dissolved in an organic solvent, and is suitable for preparing photoelectric devices by adopting processing methods such as printing and the like. The conjugated polymer containing the non-centrosymmetric benzodithiazole can be used as a photovoltaic active layer and the like to be applied to photoelectric devices, the short-circuit current density and filling factors of the devices are remarkably improved, and the conjugated polymer has a good application prospect.

Description

Technical Field

[0001] The invention relates to the field of conjugated polymers and polymer optoelectronic materials, and mainly to a conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole, and a preparation method and application thereof. Background Art

[0002] Due to the gradual depletion of fossil energy, more efficient use of clean and renewable energy such as solar energy, wind energy, geothermal energy, and tidal energy has become a very important topic in the 21st century. Solar cells occupy a pivotal position in the exploration of new energy. Compared with inorganic photovoltaic materials such as silicon and perovskite, organic materials have obvious advantages in solvent processing, such as light weight and low cost. More importantly, organic semiconductors are more likely to achieve flexibility and roll-to-roll processability for solar cells through solvent processing, which will greatly improve production efficiency. In addition, through reasonable material design and device fabrication, photon capture in specific bands can be obtained, which has broad application prospects in the fields of construction and environmental engineering.

[0003] Organic solar cells (OSCs) show great promise in smart city and indoor applications due to their advantages in manufacturing lightweight, flexible, and semi-transparent photovoltaic panels through cost-effective printing methods. The power conversion efficiency (PCE) of OSCs has increased rapidly over the past two decades, with the main contributions coming from the innovation of photoactive layer donor and acceptor materials, device optimization, and interface engineering. Among them, donor and acceptor materials jointly control the photophysical processes of light absorption, exciton dissociation, and carrier transport, and therefore play a vital role in the performance of OSCs. The improvement of PCE is inseparable from the increasing understanding of the structure-property relationship of active layer materials. From a chemical point of view, the molecular structure of donor and acceptor materials determines the basic properties of organic solar cells, such as absorption spectrum, molecular energy level, and charge mobility, which further determines the photoelectric conversion efficiency of organic solar cells. Therefore, improving the efficiency of organic solar cells through donor and acceptor molecular design is currently the focus of research in this field.

[0004] The donor polymer molecules of organic solar cells are generally copolymerized by electron-rich units (D units) and electron-deficient units (A units), and are mainly composed of conjugated main chains, side chains, and substituents. The polymer structure of this DA copolymer has the function of optimizing energy levels, which is beneficial to improving the open circuit voltage (VOC) of the device without changing the absorption. In the synthetic design of DA copolymers, many factors must be considered. From the perspective of molecular engineering, the selection of appropriate conjugated repeating units determines the energy level and band gap; the selection of appropriate side chains largely determines the solubility in the processing solvent; the conjugated main chain and side chains have a significant effect on the aggregation and intermolecular interactions of the active layer. From the perspective of polymer engineering, it is necessary to carefully balance the molecular weight, dispersibility, solubility in the processing solvent, and the viscosity of the resulting solution. For specific molecular design, the star molecule PM6 is generally selected as the basis for modification. The main modification strategies include electron-deficient unit design, side chain engineering, substituent modification, ternary copolymer design, etc.

[0005] For the donor polymer of DA copolymerization, polymer materials containing centrosymmetric benzodithiazole electron-deficient units have been widely used. The rigidity, high planarity and large π conjugation extension of benzodithiazole can reduce the steric hindrance between adjacent rings, thereby improving the coplanarity of the molecule and tighter interchain packing in the solid film. In addition, due to the strong electron deficiency of thiazole, the heterocyclic ring containing thiazole has a good frontier molecular orbital distribution, which is conducive to effective intramolecular charge transfer, thereby obtaining a good energy level distribution. When polymer materials containing centrosymmetric benzodithiazole electron-deficient units are used in organic solar cell optoelectronic devices, high open circuit voltage and low energy loss (ELOSS) can be obtained, but they have relatively low short circuit current density (JSC) and fill factor (FF), which makes the final battery device PCE low, limiting its application range.

[0006] In summary, it is necessary to develop a new technical solution to solve the defects and shortcomings in the existing technology. Summary of the invention

[0007] The object of the present invention is to provide a conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole and a preparation method and application thereof in view of the shortcomings of the prior art. Compared with centrosymmetric benzodithiazole, the non-centrosymmetric benzodithiazole with an asymmetric structure makes the molecule have a larger dipole moment, which not only enhances the intermolecular interaction and π-π stacking, but also optimizes the micromorphology of the active layer, and can significantly improve the short-circuit current density and filling factor of the organic solar cell. Therefore, it can be predicted that the conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole will have good photoelectric properties, good absorption of sunlight, adjustable lowest unoccupied molecular orbital energy level (LUMO) and highest occupied molecular orbital energy level (HOMO), excellent rigidity and high planarity, large conjugated extension, good intermolecular interaction, can be used to make polymer solar cell active layer, and is a class of materials with commercial application prospects. However, conjugated polymer optoelectronic materials containing non-centrosymmetric benzodithiazoles have not been reported in the field so far as a promising optoelectronic material. The present invention synthesized a new type of non-centrosymmetric benzodithiazole unit and its polymer for the first time and successfully applied it in the field of optoelectronic materials. The obtained materials have good optoelectronic properties when applied to optoelectronic devices.

[0008] An object of the present invention is to provide a conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole, wherein the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole has the following structure:

[0009]

[0010] in,

[0011] n is a natural number selected from 1 to 10000;

[0012] x is selected from 0.05-0.95;

[0013] y is selected from 0.05-0.95;

[0014] And x+y=1;

[0015] D is the electron donating unit;

[0016] R is a solubilizing group.

[0017] Furthermore, the D is selected from one or more of the following structures:

[0018]

[0019] Furthermore, the D is a substituent not shown; specifically, the substituent may be but not limited to various solubilizing alkyl groups or alkyl derivatives; for example, one or more hydrogen atoms on the alkyl group are replaced by other groups, such as hydroxyalkyl, carboxylalkyl, aminoalkyl, cyanoalkyl, etc.; the alkyl group may be but not limited to a straight chain, branched chain or cyclic chain.

[0020] Further, the R is selected from a C1-C40 alkyl group or an alkyl derivative, or a C1-C40 alkoxy group or an alkoxy derivative;

[0021] Further, one or more carbon atoms on the alkyl derivative or alkoxy derivative are substituted by one or more functional groups selected from the group consisting of oxygen atoms, alkenyl groups, alkynyl groups, aryl groups, ester groups, nitrile groups, amine groups, quaternary ammonium salt groups, amine oxides, diethanolamine, pyridine oxides, quaternary phosphonium salt groups, phosphate groups, phosphate ester groups, sulfonate groups, carboxyl groups, and hydroxyl groups, and / or one or more hydrogen atoms on the alkyl derivative or alkoxy derivative are substituted by one or more functional groups selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms;

[0022] Another object of the present invention is to provide a method for preparing the above-mentioned conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole, and the preparation method of the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole is shown in the following process:

[0023]

[0024] S1, iodination reaction of m-phenylenediamine (compound 1) to obtain 4,6-diiodobenzene-1,3-diamine (compound 2);

[0025] S2, subjecting the compound 2 to a ring-closing reaction to obtain a non-centrosymmetric benzodithiazole (compound 3);

[0026] S3, brominating the compound 3 with liquid bromine to obtain dibromo non-centrosymmetric benzodithiazole (compound 4);

[0027] S4, coupling the compound 4 with tributyltin thiophene having a solubilizing side chain R to obtain compound 5 (a coupled thiophene derivative containing a non-centrosymmetric benzodithiazole);

[0028] S5, subjecting the compound 5 to NBS bromination reaction to obtain compound 6 (a target monomer of a dibrominated coupled thiophene derivative containing non-centrosymmetric benzodithiazole);

[0029] S6. Mix the compound 6 with a bistrimethyltin functionalized electron donor, add a palladium catalyst to carry out Stille reaction to obtain compound 7 (conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole).

[0030] Further, in step S1, the iodination reaction uses potassium iodide to introduce an iodine substituent into compound 1;

[0031] Further, in step S1, the molar ratio of compound 1 in the iodination reaction to potassium iodide is 1:0.5-2;

[0032] Furthermore, in step S2, the molar ratio of the compound 2, potassium sulfide and ammonium acetate in the reaction is 1:3-6:5-12; and the reaction temperature is 110-140°C.

[0033] Furthermore, in step S1, the 4,6-diiodobenzene-1,3-diamine is obtained by reacting in a solution with p-m-phenylenediamine as a raw material under the action of potassium iodide and hydrogen peroxide as a catalyst.

[0034] Furthermore, in step S2, the non-centrosymmetric benzodithiazole is obtained by heating reaction in a solution under the protection of an inert gas with 4,6-diiodobenzene-1,3-diamine as a raw material in the presence of ammonium acetate and cuprous iodide.

[0035] Furthermore, in step S3, the dibrominated non-centrosymmetric benzodithiazole is obtained by adding liquid bromine to the non-centrosymmetric benzodithiazole under alkaline conditions and heating the reaction.

[0036] Another object of the present invention is to disclose the application of the above-mentioned conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole.

[0037] As a preferred technical solution, the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole is dissolved in an organic solvent, processed into a polymer film by spin coating, printing, roll-to-roll or inkjet printing solution, and used as a carrier transport layer, light-emitting layer or photovoltaic active layer in photovoltaic, light-emitting or field effect transistor optoelectronic devices.

[0038] As a preferred technical solution, the photovoltaic device consists of a substrate, a cathode, a cathode interface layer, a light absorbing layer, an anode interface layer, and an anode, or a substrate, an anode, an anode interface layer, a light absorbing layer, a cathode interface layer, and a cathode stacked in sequence.

[0039] As a preferred technical solution, the anode material is preferably aluminum, silver or gold.

[0040] As a preferred technical solution, the anode interface layer is an organic conjugated polymer or an inorganic semiconductor.

[0041] As a preferred technical solution, the cathode is at least one of metal, metal oxide, doped tin dioxide, zinc oxide, indium gallium zinc oxide or graphene and its derivatives; the substrate is at least one of glass, flexible material, metal, alloy or stainless steel film.

[0042] In an organic / polymer solar cell device (ITO cathode / electron transport layer / photoactive layer / hole transport layer / metal anode, or ITO anode / hole transport layer / photoactive layer / electron transport layer / metal cathode), the application method of the above-mentioned conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole is as follows: the conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole is used as a donor material and other acceptor materials are dissolved in an organic solvent such as toluene, chloroform, chlorobenzene, xylene, etc. in a certain proportion, and spin-coated on an ITO electrode to prepare a photovoltaic active layer, and the process control such as solvent, additive, solvent vapor treatment, thermal annealing, etc. is used to form a morphology structure that is conducive to carrier separation, transmission, and collection, so as to realize a high-efficiency polymer solar cell. This polymer not only has a large conjugated plane, ensuring that it has good carrier mobility; but also the electron-deficient unit of thiazole makes the molecule have a stronger electron-withdrawing ability, ensuring that the polymer has lower HOMO and LUMO energy levels; copolymers with suitable conjugated units may obtain a wider absorption spectrum; this type of newly developed conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole can be used as a polymer donor and may realize efficient all-polymer solar cell devices.

[0043] The present invention has the following beneficial effects:

[0044] 1. The conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole of the present invention is composed of benzene and two thiazole units, and has a large conjugated plane structure, which can reduce the steric hindrance between adjacent rings, thereby improving the coplanarity of the molecule and the tighter interchain filling in the solid film and ensuring that it has good carrier mobility. This feature can not only improve the filling factor of the solar cell of the conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole, but also prepare a thick film photovoltaic active layer to achieve effective absorption and utilization of sunlight.

[0045] 2. Compared with traditional organic / polymer materials, the conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole of the present invention is composed of two electron-deficient units of thiazole connected together, and has a stronger electron-deficient ability, so that the conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole has lower HOMO and LUMO energy levels, and is used as a donor in polymer solar cells to obtain a higher open circuit voltage.

[0046] 3. Compared with the symmetrical structure, the non-centrosymmetric benzodithiazole of the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole has a larger dipole moment, which not only enhances the intermolecular interaction and π-π stacking, but also optimizes the micromorphology of the active layer, which can significantly improve the short-circuit current density and filling factor of organic solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 (A) is the structural formula of the target intermediate compound 3 synthesized in Example 1;

[0048] Figure 1 (B) is the structural formula of the target intermediate compound a2 synthesized in the comparative example.

[0049] Figure 2 The NMR spectrum of the target intermediate compound 3 synthesized in Example 1 ( 1 H NMR);

[0050] Figure 3 The NMR spectrum of the target intermediate compound a2 synthesized in the comparative example ( 1 1H NMR). DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the accompanying drawings and Example 1, but the embodiments and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art.

[0052] The practice of the present invention can adopt the conventional techniques of organic chemistry within the relevant field technology. In the following Example 1, efforts are made to ensure the accuracy of the numbers used (including amounts, temperatures, reaction times, etc.), but some experimental errors and deviations should be considered. The temperatures used in the following Example 1 are expressed in ° C, and the pressure is atmospheric pressure or near atmospheric pressure. The solvents used are analytically pure or chromatographically pure, and all reactions are carried out in an inert gas atmosphere. Unless otherwise noted, all reagents are obtained through commercial channels.

[0053] The Stille reaction of the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole is shown in the following general formula:

[0054]

[0055] Example 1

[0056] A conjugated polymer optoelectronic material Cis-BBTz containing non-centrosymmetric benzodithiazole, the structural formula of which is shown below:

[0057]

[0058] Its synthetic route is as follows:

[0059]

[0060] S1. Synthesis of Compound 2

[0061] 12 mL of concentrated sulfuric acid was added to 350 mL of methanol, and 16.2 g of compound 1, 49.8 g of potassium iodide and 20.4 g of hydrogen peroxide were added to the mixed solution and reacted at room temperature for 2 h. After the reaction, the reaction solution was poured into water, filtered, and recrystallized using dichloromethane: petroleum ether (10:1, v / v) to obtain 8 g of gray needle-shaped solid, namely compound 2, with a yield of 15%.

[0062] S2. Synthesis of Compound 3

[0063] Dissolve 1.78g of compound 2, 3.26g of potassium sulfide, 4.57g of ammonium acetate and 0.38g of cuprous iodide in 250mL of DMSO, add 10mL of water, and heat to 130°C under an argon atmosphere. After reacting for 24h, filter and wash with dichloromethane. Transfer the filtrate to a separatory funnel and add water. Extract with dichloromethane, wash the organic phase with brine, dry, and concentrate in vacuo. The residue is purified by silica gel column chromatography to obtain 0.2g of yellow solid, i.e., compound 3, with a yield of 20%.

[0064] S3. Synthesis of Compound 4

[0065] 2 g of compound 3 and 1.44 g of K2CO3 were dissolved in 50 mL of DMF, 8 mL of liquid bromine was added, and the mixture was heated to 120°C. After reacting for 3 h, the reaction solution was poured into a saturated sodium bisulfite solution for quenching, and filtered by suction. After drying, 2.3 g of brown powder, i.e., compound 4, was obtained, with a yield of 63%.

[0066] S4. Synthesis of Compound 5

[0067] 2 g of compound 4 and 9.26 g of 2-(4-(2-butyloctyl)thiophene)trimethylstannane were dissolved in degassed toluene, 0.33 g of tetrakis(triphenylphosphine)palladium catalyst was added, and the mixture was heated to 150° C. After reacting for 24 h, the reaction solution was subjected to reduced pressure rotary evaporation to remove toluene, and purified by silica gel column chromatography to obtain 0.8 g of an orange-yellow solid, namely compound 5, with a yield of 20%.

[0068] S5. Synthesis of Compound 6

[0069] 0.4 g of compound 5 was dissolved in 20 mL of CF, and 0.2 g of NBS was added in batches in a dark environment, and the reaction was carried out at room temperature for 3 h. After the reaction was completed, the reaction solution was poured into water for quenching, extracted with dichloromethane, dried and concentrated to obtain 0.3 g of orange-yellow solid, namely compound 6, with a yield of 61%.

[0070] S6. Synthesis of Compound 8

[0071] 103 mg of compound 6, 105 mg of compound 7, 4.5 mg of tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and 9.0 mg of tris(o-methylphenyl)phosphine (P(o-Tol)3) were dissolved in a mixed solvent of 10 mL of toluene and 5 mL of tetrahydrofuran. Under argon protection, the reaction was refluxed for 20 hours. After cooling to room temperature, the reaction solution was dropped into 300 mL of methanol for precipitation and filtered to obtain a solid. After extraction with acetone, methanol, n-hexane and dichloromethane in a Soxhlet extractor for 24 hours respectively, the polymer was finally washed with chloroform, precipitated in methanol, filtered and dried in vacuum. 103 mg of compound 8, i.e., Cis-BBTz, was obtained with a yield of 75%.

[0072] Example 2

[0073] A conjugated polymer optoelectronic material BT-Cis-BBTz containing non-centrosymmetric benzodithiazole, the structural formula of which is shown below:

[0074]

[0075] The preparation method of Example 2 is the same as that of Example 1, except that step S6 is modified as follows:

[0076] 103 mg of compound 6, 59.5 mg of 5,5-bistrimethyltin-2,2'-bithiophene, and 4.5 mg of tri(dibenzylideneacetone)dipalladium were dissolved in a mixed solvent of 10 mL of toluene and 5 mL of tetrahydrofuran. Under argon protection, the reaction was refluxed for 20 hours. After cooling to room temperature, the reaction solution was dropped into 300 mL of methanol for precipitation and filtered to obtain a solid. After extraction with acetone, methanol, n-hexane, and dichloromethane in a Soxhlet extractor for 24 hours, the polymer was finally washed with chloroform, precipitated in methanol, filtered, and dried in vacuum. 130 mg of polymer, i.e., solid BT-Cis-BBTz, was obtained with a yield of 80%.

[0077] Example 3

[0078] A conjugated polymer optoelectronic material FT-Cis-BBTz containing non-centrosymmetric benzodithiazole, the structural formula of which is shown below:

[0079]

[0080] The preparation method of Example 3 is the same as that of Example 1, except that step S6 is modified as follows:

[0081] 103 mg of compound 6, 54.0 mg of 3,4-difluoro-2,5-bistrimethyltinthiophene, and 4.5 mg of tris(dibenzylideneacetone)dipalladium were dissolved in a mixed solvent of 10 mL of toluene and 5 mL of tetrahydrofuran. Under argon protection, the reaction was refluxed for 20 hours. After cooling to room temperature, the reaction solution was dropped into 300 mL of methanol for precipitation and filtered to obtain a solid. After extraction with acetone, methanol, n-hexane, and dichloromethane in a Soxhlet extractor for 24 hours, the polymer was finally washed with chloroform, precipitated in methanol, filtered, and dried in vacuum. 120 mg of polymer, i.e., solid FT-Cis-BBTz, was obtained with a yield of 78%.

[0082] Example 4

[0083] A conjugated polymer optoelectronic material DFT-Cis-BBTz containing non-centrosymmetric benzodithiazole, the structural formula of which is shown below:

[0084]

[0085] The preparation method of Example 4 is the same as that of Example 1, except that step S6 is modified as follows:

[0086] 103 mg of compound 6, 63.9 mg of (3,3'-difluoro-[2,2'-bithiophene]-5,5'-diyl)bistrimethyltin, and 4.5 mg of tris(dibenzylideneacetone)dipalladium were dissolved in a mixed solvent of 10 mL of toluene and 5 mL of tetrahydrofuran. Under argon protection, the reaction was refluxed for 20 hours. After cooling to room temperature, the reaction solution was dropped into 300 mL of methanol for precipitation and filtered to obtain a solid. After extraction with acetone, methanol, n-hexane, and dichloromethane in a Soxhlet extractor for 24 hours, the polymer was finally washed with chloroform, precipitated in methanol, filtered, and dried in vacuum. 125 mg of polymer, i.e., solid DFT-Cis-BBTz, was obtained with a yield of 75%.

[0087] Comparative Example

[0088] The polymer optoelectronic material BBTz containing central symmetrical benzodithiazole has the following structural formula:

[0089]

[0090] Its synthetic route is as follows:

[0091]

[0092] (1) Synthesis of compound a2

[0093] Dissolve 10g of compound a1 (2,5-diamino-1,4-benzenedithiol dihydrochloride), 24.3g of triethyl orthoformate, 6.5g of pyridine and 1.24g of ytterbium trifluoromethanesulfonate in 250mL of DMA and heat to 55°C under argon atmosphere. After reacting for 3h, pour into water and filter. Dry to obtain 5.3g of yellow powder, i.e., compound a2 (centrosymmetric benzodithiazole), with a yield of 67%.

[0094] (2) Synthesis of compound a3

[0095] Dissolve 2g of compound a2 and 1.44g of K2CO3 in 50mL of DMF, add 8mL of liquid bromine, and heat to 120°C. After reacting for 3h, pour the reaction solution into a saturated sodium bisulfite solution to quench, filter, and dry to obtain 2.3g of brown powder compound a3 (dibromocentrosymmetric benzodithiazole), with a yield of 63%.

[0096] (3) Synthesis of compound a4

[0097] 2 g of compound a3 and 9.26 g of 2-(4-(2-butyloctyl)thiophene)trimethylstannane were dissolved in degassed toluene, 0.33 g of tetrakistriphenylphosphine palladium was added, and the mixture was heated to 150° C. After reacting for 24 h, the reaction solution was subjected to reduced pressure rotary evaporation to remove toluene, and purified by silica gel column chromatography to obtain 0.8 g of orange-yellow solid compound a4 (centrosymmetric benzodithiazole coupled thiophene derivative) with a yield of 20%.

[0098] (4) Synthesis of Compound a5

[0099] 0.4 g of compound a4 was dissolved in 20 mL of CF, and 0.2 g of NBS was added in batches in a dark environment, and the mixture was reacted at room temperature for 3 h. After the reaction, the reaction solution was poured into water to quench, extracted with dichloromethane, dried and concentrated to obtain 0.3 g of orange-yellow solid compound a5 (coupling thiophene derivative monomer of dibromo-centrosymmetric benzodithiazole), with a yield of 61%.

[0100] (5) Synthesis of Compound a6

[0101] 103 mg of compound a5, 105 mg of compound 6, 4.5 mg of tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and 9.0 mg of tris(o-methylphenyl)phosphine (P(o-Tol)3) were dissolved in a mixed solvent of 10 mL of toluene and 5 mL of tetrahydrofuran. Under argon protection, the reaction was refluxed for 20 hours. After cooling to room temperature, the reaction solution was dropped into 300 mL of methanol for precipitation and filtered to obtain a blood-red solid. After extraction with acetone, methanol, n-hexane and dichloromethane in a Soxhlet extractor for 24 hours respectively, the polymer was finally washed with chloroform, precipitated in methanol, filtered and dried in vacuum. 103 mg of dark red compound a6, i.e., solid polymer BBTz, was obtained with a yield of 75%.

[0102] Figure 1 (A) is the structural formula of the target intermediate compound 3 synthesized in Example 1;

[0103] Figure 1 (B) is the structural formula of the target intermediate compound a2 synthesized in the comparative example.

[0104] Figure 2 The NMR spectrum of the target intermediate compound 3 synthesized in Example 1 ( 1 H NMR);

[0105] Figure 3 The NMR spectrum of the target intermediate compound a2 synthesized in the comparative example ( 1 1H NMR).

[0106] Test Case

[0107] Taking the Cis-BBTz synthesized in Example 1 and the BBTz synthesized in the comparative example as examples, they were blended with the acceptor and then the current-voltage curves were tested to illustrate their application as donors in polymer solar cell devices.

[0108] The specific preparation process of polymer solar cell devices is as follows:

[0109] ITO conductive glass, the sheet resistance is about 20Ω / cm 2 , pre-cut into 15mm×15mm square glass blocks. Use acetone, micron-grade semiconductor detergent, deionized water, isopropanol ultrasonic cleaning in turn, and place in a constant temperature oven after nitrogen purge. Spin-coat a 20nm thick cathode interface layer PEDOT on ITO, then spin-coat the active layer material Cis-BBTz / PY-IT or BBTz / PY-IT with a thickness of about 100nm, and finally evaporate the Ag electrode as the anode to complete the device preparation.

[0110] All preparation processes were carried out in a glove box with a nitrogen atmosphere, and PY-IT was used as an electron acceptor. The structural formula of PY-IT is as follows:

[0111]

[0112] The polymer solar cell device comprises, from bottom to top, an ITO cathode (20 nm) / a cathode interface layer PEDOT (20 nm) / an active layer (100 nm) / an anode Ag (100 nm).

[0113] The current-voltage characteristics of the polymer solar cell device were measured.

[0114] The test results are shown in Table 1.

[0115] Table 1: Performance parameters of polymer solar cell devices

[0116]

[0117] It can be seen from Table 1 that the solar cell based on the non-centrosymmetric benzodithiazole conjugated polymer optoelectronic material Cis-BBTz as the system has obtained better short-circuit current and fill factor than the centrosymmetric benzodithiazole polymer BBTz, which confirms that the larger dipole moment of the non-centrosymmetric structure can enhance the intermolecular interaction and π-π stacking, optimize the micromorphology of the active layer, and thus achieve higher battery energy conversion efficiency.

[0118] The above-mentioned embodiment 1 of the present invention is only an example for clearly illustrating the present invention, and is not intended to limit the implementation mode of the present invention. For those skilled in the art, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation modes here. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A conjugated polymer photoelectric material containing non-centrosymmetric benzodithiazole, characterized in that: The conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole has the following structure: in, n is a natural number selected from 1 to 10000; x is selected from 0.05-0.95; y is selected from 0.05-0.95; And x+y=1; D is the electron donating unit; R is a solubilizing group.

2. The conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 1, characterized in that: The D is selected from one or more of the following structures:

3. The conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 1, characterized in that: The R is selected from a C1-C40 alkyl group or an alkyl derivative, or a C1-C40 alkoxy group or an alkoxy derivative; One or more carbon atoms on the alkyl derivative or alkoxy derivative are substituted by one or more functional groups selected from the group consisting of oxygen atoms, alkenyl groups, alkynyl groups, aryl groups, ester groups, nitrile groups, amine groups, quaternary ammonium salt groups, amine oxides, diethanolamine, pyridine oxides, quaternary phosphonium salt groups, phosphate groups, phosphate ester groups, sulfonate groups, carboxyl groups, and hydroxyl groups; and / or One or more hydrogen atoms on the alkyl derivative or alkoxy derivative are replaced by one or more functional groups selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms and iodine atoms.

4. The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to any one of claims 1 to 3, characterized in that: The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole comprises the following steps: S1, iodizing p-phenylenediamine to obtain 4,6-diiodobenzene-1,3-diamine; S2, subjecting the 4,6-diiodobenzene-1,3-diamine to a ring-closing reaction to obtain a non-centrosymmetric benzodithiazole; S3, brominating the non-centrosymmetric benzodithiazole with liquid bromine to obtain dibromo non-centrosymmetric benzodithiazole; S4, coupling the dibromo non-centrosymmetric benzodithiazole with tributyltin thiophene having a solubilizing side chain R to obtain a coupled thiophene derivative containing a non-centrosymmetric benzodithiazole; S5, subjecting the coupled thiophene derivative containing non-centrosymmetric benzodithiazole to NBS bromination reaction to obtain a dibrominated coupled thiophene derivative containing non-centrosymmetric benzodithiazole target monomer; S6. Mixing the target monomer of the dibrominated coupled thiophene derivative containing non-centrosymmetric benzodithiazole with a bistrimethyltin functionalized electron donor, adding a palladium catalyst to carry out Stille reaction, and obtaining a conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole.

5. The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 4, characterized in that: In step S1, the molar ratio of m-phenylenediamine to potassium iodide in the iodination reaction is 1:0.5-2.

6. The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 4, characterized in that: In step S2, the molar ratio of 4,6-diiodobenzene-1,3-diamine, potassium sulfide and ammonium acetate in the reaction is 1:3-6:5-12, and the reaction temperature is 110-140°C.

7. The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 4, characterized in that: In step S1, the 4,6-diiodobenzene-1,3-diamine is obtained by reacting in a solution with p-m-phenylenediamine as a raw material under the action of potassium iodide and hydrogen peroxide as a catalyst.

8. The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 4, characterized in that: In step S2, the non-centrosymmetric benzodithiazole is obtained by heating reaction in a solution under the protection of inert gas with 4,6-diiodobenzene-1,3-diamine as a raw material in the presence of ammonium acetate and cuprous iodide.

9. The method for preparing the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to claim 4, characterized in that: In step S3, the dibromo non-centrosymmetric benzodithiazole is obtained by adding liquid bromine to non-centrosymmetric benzodithiazole under alkaline conditions and heating the mixture for reaction.

10. Use of the conjugated polymer optoelectronic material containing non-centrosymmetric benzodithiazole according to any one of claims 1 to 3.

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