An organic solar cell with a specific vertical distribution morphology and its preparation process

Abstract

The present invention belongs to the technical field of solar cells, and specifically relates to an organic solar cell with a specific vertical distribution morphology and a preparation process thereof. The solar cell device processed based on the layer-by-layer processing method has an ideal photoactive layer with a specific vertical distribution structure, which gives the device better photovoltaic performance. Through continuous LBL thin film deposition of electron donors and acceptors, the mutual diffusion between the donor and the acceptor improves the charge transport balance, reduces bimolecular charge recombination, and enables the device to have better film morphology robustness and less charge removal, greatly improving the thermal stability of the device. It adds solvent additives and solid molecular additives to the non-fullerene acceptor solution at the same time. Compared with the addition of only solvent additives, the device modified based on liquid and solid molecular additives has higher device stability and reproducibility, and is insensitive to the amount of additives used, which is conducive to the future large-scale industrial application of OSCs.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells, and in particular relates to an organic solar cell with a specific vertical distribution morphology and a preparation process thereof. Background Art

[0002] In the 21st century, with the rapid development of modernization, the accelerated process of engineering and the extensive use of natural fossil fuels such as coal and oil have aggravated environmental pollution and made the energy crisis appear. In order to achieve sustainable development, solar energy, which is available everywhere, has entered people's field of vision as a green energy. The energy radiated to the earth each year is as high as 3×10 24 J is the cleanest, most efficient and abundant energy source with unique advantages. Therefore, the development of photovoltaic energy and the development of new solar cells have attracted more and more attention.

[0003] Organic solar cells have become a research hotspot due to their low preparation cost, simple process, easily adjustable optoelectronic properties, semi-transparency, and large-area roll-to-roll printing. High-efficiency organic solar cells remain the primary research priority and the key to their industrialization. In recent years, due to the advantages of non-fullerene small molecule acceptor materials such as chemical modification adjustability, low energy loss, and easy synthesis, bulk heterojunction solar cells based on donor polymers / non-fullerene small molecule acceptors have developed rapidly. All-polymer solar cells (all-PSCs) prepared from polymer donors / acceptors have advantages such as good mechanical force tolerance and morphological stability, and are also an important development direction for solar cells.

[0004] Current research focuses on how to effectively utilize interface modification, morphology optimization, additive design, and multi-component applications to improve the photoelectric conversion efficiency of heterojunction organic solar cells. Most high-performance organic solar cells are prepared with the aid of high-boiling-point solvent additives to optimize charge transport properties. While this approach offers advantages in improving photovoltaic performance, it also compromises device stability and reproducibility, imposes stringent processing conditions, and can lead to residue-induced morphological degradation.

[0005] Although bulk heterojunction (BHJ) organic solar cells have achieved great success, this method of processing the active layer using a single solution has certain disadvantages. First, due to various factors such as temperature, the properties of the blended solution of donor and acceptor materials tend to change over time and cannot be stored for a long time. Second, due to the interaction between the donor and acceptor, the processed bulk heterojunction is prone to vertical phase separation.

[0006] Therefore, in bulk heterojunction solar cells, it is difficult to control the vertical distribution morphology of the active layer in a precise manner. Therefore, a low-cost, high-performance processing method with precise vertical morphology control, the layer-by-layer (LBL) method for preparing organic solar cells, has emerged. In the double-layer processing process, both the donor layer and the acceptor layer can be processed separately, thereby reducing the dependence on processing conditions, such as D / A ratio, additives, and solvents; in BHJ devices, in order to achieve optimal phase separation, too many parameters must be considered, including D / A ratio, solubility, miscibility of donor and acceptor, solvents and additives, thermal annealing and solvent annealing, etc. Summary of the Invention

[0007] In response to the above problems, the purpose of the present invention is to provide an organic solar cell with a specific vertical distribution morphology and its preparation process. The device processed based on the layer-by-layer processing method has an ideal photoactive layer with a specific vertical distribution structure, giving the device better photovoltaic performance.

[0008] The technical contents of the present invention are as follows:

[0009] The present invention provides an organic solar cell with a specific vertical distribution morphology, wherein the device structure of the organic solar cell includes: a transparent conductive anode substrate, an anode interface, an organic electron donor, an organic electron acceptor, a cathode interface, and a cathode electrode;

[0010] The organic electron donor includes one or more polymer electron donor materials;

[0011] A solvent additive and a solid molecular additive are simultaneously added to the organic electron acceptor solution;

[0012] The solvent additive includes one or more of 1,8-diiodooctane (DIO) and chloronaphthalene (CN);

[0013] The solid molecular additive includes one or more of 2,2':5',2"-terthiophene (FEDE) and its derivatives. The chemical structures of the FEDE (structural formula (1)) and its derivatives (structural formulas (2) to (8)) include the following:

[0014]

[0015] Among them, the FEDE class also includes structures in which any site on other FEDEs is substituted by one or more of fluorine atoms, chlorine atoms, and bromine atoms;

[0016] The preparation of the FEDE comprises the following steps:

[0017] 1) at room temperature and under a nitrogen atmosphere, tetrahydrofuran, 2-bromothiophene, magnesium, and a catalytic amount of iodine were mixed, stirred vigorously for reaction, and then cooled to room temperature to obtain a reaction mixture;

[0018] 2) adding 2,5-dibromothiophene and Pd2(dppf)2 to the reaction mixture for reaction, followed by reflux, cooling to room temperature, and quenching the reaction by adding water and diluted acid until a neutral reactant is obtained;

[0019] 3) The neutral reactant was placed in a large amount of water, and the reaction mixture was extracted with dichloromethane. The organic layer was dried over anhydrous Na2SO4 and evaporated to a solid organic molecule. The crude product was purified by silica gel column chromatography using 4:1 petroleum ether / dichloromethane as the eluent to obtain the FEDE product.

[0020] The amount of the solvent additive is 0.1-1.5% of the volume of the solvent, and the amount of the solid molecular additive is 0.5-10% of the mass of the organic material.

[0021] The addition of the FEDE can enhance the π-π stacking between non-fullerene acceptor molecules, thereby promoting the charge transport characteristics in the active layer, making the active layer morphology have more ordered, denser molecular stacking and better vertical distribution, resulting in the device having good long-term thermal stability and storage stability, thereby ultimately improving the device photoelectric conversion efficiency.

[0022] In the device structure, the material of the transparent conductive anode substrate includes ITO, the material of the anode interface includes 2PACz, the material of the organic electron acceptor includes one or more non-fullerene donor materials, the material of the cathode interface includes PDINN, and the material of the cathode electrode includes Ag.

[0023] The present invention also provides a method for preparing an organic solar cell having a specific vertical distribution morphology, comprising the following steps:

[0024] On a transparent conductive anode substrate, spin-coating the anode interface, organic electron donor, organic electron acceptor, cathode interface and cathode electrode in sequence from bottom to top;

[0025] The material of the transparent conductive anode substrate includes ITO, which is ultrasonically cleaned and dried, and irradiated under an ozone-ultraviolet lamp;

[0026] The anode interface material includes 2PACz, which is dissolved in anhydrous ethanol to prepare a solution with a concentration of 0.2-0.3 mg / mL, heated and stirred at 45-55°C and 90-110 rpm for 0.5-1 hour, and then spin-coated on a transparent conductive anode with a thickness of 2-5 nm, and annealed at 90-110°C for 8-12 minutes;

[0027] The organic electron donor is prepared by dissolving the polymer donor material in pure chlorobenzene to prepare a solution with a concentration of 6-12 mg / mL, heating and stirring at 60-70°C and 120-140 rpm for 2-4 hours, and then spin-coating the solution on the anode interface to a thickness of 50-80 nm.

[0028] The polymer donor materials include PM6, PBDB-T, etc.

[0029] The organic electron acceptor is prepared by dissolving a non-fullerene acceptor in a solvent to which a solvent additive and a solid molecule additive are added to prepare a solution, spin-coating the solution on an organic electron donor to obtain a double-layer structure, placing the solution in a vacuum oven for 30 minutes, and then annealing the solution at 100-120° C. for 8-10 minutes.

[0030] The cathode interface material includes PDINN, which is prepared by dissolving PDINN in pure methanol to prepare a solution with a concentration of 0.5-1.5 mg / mL, shaking it well, wrapping it in tin foil, and placing it in a dark place. Then, the solution is spin-coated on the active layer of the double-layer structure to a thickness of 5-10 nm.

[0031] The cathode electrode material includes Ag, which is prepared by vacuum thermal evaporation of Ag at a vacuum degree of 4×10 -4 ~6×10 -4 Pa, under the condition of controlling the evaporation rate, a cathode with a thickness of 0 to 100 nm is prepared;

[0032] The rate of evaporating metal Ag is 0.01 nm / s when the thickness is 0-5 nm, 0.02 nm / s when the thickness is 5-10 nm, less than 0.05 nm / s when the thickness is 10-20 nm, less than 0.1 nm / s when the thickness is 20-35 nm, and less than 0.35 nm / s when the thickness is 35-100 nm.

[0033] The beneficial effects of the present invention are as follows:

[0034] Compared to conventional BHJ structured devices, the organic solar cells of the present invention, which feature a specific vertical distribution morphology, possess a photoactive layer with an ideal specific vertical distribution structure, resulting in better photovoltaic performance. By continuously depositing electron donors and acceptors through LBL thin films, the interdiffusion between the donors and acceptors improves charge transport balance, reduces bimolecular charge recombination, and provides the device with better film morphology robustness and less charge removal, significantly enhancing its thermal stability. The superior performance of the dual-layer structured device can be attributed to the gradient of donor and acceptor distribution during solution processing, which is considered to be the ideal structure for organic solar cell devices, forming a good interpenetrating network while also achieving a good vertical distribution.

[0035] In the cell, a solvent additive and a solid molecular additive are simultaneously added to the non-fullerene acceptor solution. Compared with adding only the solvent additive, the device modified based on the liquid and solid molecular additives has higher device stability and reproducibility, and is insensitive to the amount of additives used, which is conducive to the future large-scale industrial application of OSCs.

[0036] The present invention relates to a process for preparing an organic solar cell with a specific vertical distribution morphology. Regarding the interface material, since PEDOT:PSS in conventional face-mounted structures is acidic and corrodes ITO, thus affecting device stability, 2PACz is used as the anode interface. This 2PACz is functionalized directly on the ITO surface from a solution, forming a smooth interface with high-density coverage and uniform morphology. This reduces ohmic contact resistance and bimolecular recombination losses with the active layer, resulting in a longer carrier lifetime and greater carrier density. The enhanced hole transport performance and improved interface contact significantly improve the operation and long-term stability of devices using 2PACz as the anode interface. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the battery structure of Example 1 and Comparative Example 1 of the present invention;

[0038] Figure 2 Schematic diagram of the battery structure of Example 2 of the present invention and Comparative Example 2;

[0039] Figure 3 Schematic diagram of the battery structure of Example 3 of the present invention and Comparative Example 3;

[0040] Figure 4 Schematic diagram of the battery structure of Example 4 of the present invention and Comparative Example 4;

[0041] Figure 5 1 is a comparison chart of test results of batteries prepared in Example 1 of the present invention and Comparative Example 1;

[0042] Figure 6 2 is a comparison chart of test results of batteries prepared in Example 2 of the present invention and Comparative Example 2;

[0043] Figure 7 3 is a comparison chart of test results of batteries prepared in Example 3 of the present invention and Comparative Example 3;

[0044] Figure 8 4 is a comparison chart of the test results of the batteries prepared in Example 4 of the present invention and Comparative Example 4. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below through specific implementation cases and accompanying drawings. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of protection of the present invention. After reading the present invention, various equivalent modifications of the present invention by those skilled in the art are all within the scope of the claims attached to this application.

[0046] Unless otherwise specified, all raw materials and reagents in the present invention are raw materials and reagents from conventional markets.

[0047] The specific preparation method of the FEDE of the present invention is as follows:

[0048] 1) At room temperature, under a nitrogen atmosphere, a catalytic amount of iodine was added to a mixture of 2-bromothiophene (4.89 g) and magnesium (0.86 g, 36 mmol) in 30 mL of tetrahydrofuran. The mixture was stirred vigorously and allowed to react gradually for about 1 hour, after which the reaction mixture was cooled to room temperature.

[0049] 2) 2,5-Dibromothiophene (2.42 g) and Pd2(dppf)2 (82 mg, 0.1 mmol) were added to the reaction mixture, and the reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was refluxed for another 4 hours, and the reaction mixture was cooled to room temperature;

[0050] 3) Water was added to the reaction mixture, followed by the addition of dilute hydrochloric acid (6M HCl) to quench the reaction until a neutral solution was obtained. The reaction mixture was poured into a large amount of water and extracted with dichloromethane (3×50 mL). The organic layer was dried over anhydrous Na2SO4 and evaporated to a solid organic layer. The crude product was purified by silica gel column chromatography using 4:1 petroleum ether / dichloromethane as the eluent. The preparation process is as follows:

[0051]

[0052] The specific preparation method of the FEDE derivative of the present invention is as follows:

[0053] 1. First step reaction:

[0054] 1) In a 1 L three-necked flask, diisopropylamine (78 mL, 546 mmol) was dissolved in 250 mL of anhydrous tetrahydrofuran. The reaction solution was cooled to -78°C. Butyl lithium (2.5 M in hexane) (218 mL, 546 mmol) was slowly added to the reaction mixture. 2,5-Dibromothiophene (27.9 mL, 248 mmol) was added to the reaction mixture. The reaction solution was stirred at -78°C for 2 hours. Chlorotrimethylsilane (76 mL, 595 mmol) was added to the resulting yellow solution. The reaction time was 1 hour. The reaction mixture was then warmed to room temperature and stirred overnight.

[0055] 2) The reaction solution was divided into portions of up to 300 mL, each portion was diluted with 200 mL of diethyl ether and 200 mL of water, after which the phases were separated, the aqueous layer was extracted with diethyl ether (2×100 mL), the combined organic phases were dried over sodium sulfate, the resulting mixture was filtered and concentrated under reduced pressure, and the crude mixture was heated to 10°C. -2 mbar vacuum distillation to obtain 3,4-dibromo-2,5-bis(trimethylsilyl)thiophene;

[0056] 2. Second step reaction:

[0057] 1) 3,4-Dibromo-2,5-bis(trimethylsilyl)-thiophene (13.626 g, 35.3 mmol) was dissolved in 141 mL of anhydrous tetrahydrofuran. The reaction mixture was cooled to -78°C. In the subsequent step, butyl lithium (2.5 M in hexane) and n-fluoro-n-(phenylsulfonyl)benzenesulfonamide were added alternately at -78°C. 14.73 mL, 36.83 mmol of BuLi was added over 15 minutes and stirred for 30 minutes.

[0058] 2) Add n-fluoro-n-(phenylsulfonyl)benzenesulfonamide (11.613 g, 36.83 mmol) to the reaction mixture and stir for 30 min. Add 7.34 mL, 18.34 mmol of BuLi over 15 min and stir for 30 min. Add n-fluoro-n-(phenylsulfonyl)benzenesulfonamide (5.784 g, 18.34 mmol) to the reaction mixture and stir for 30 min. Add BuLi (3.67 mL, 9.17 mmol) to the reaction mixture and stir for 30 min.

[0059] 3) Add n-fluoro-n-(phenylsulfonyl)benzenesulfonamide (2.7892 g, 9.17 mmol) to the reaction mixture and stir for 30 min. Add BuLi (1.83 mL, 4.59 mmol) to the reaction mixture and stir for 30 min.

[0060] 4) Add n-fluoro-n-(phenylsulfonyl)benzenesulfonamide (1.446 g, 4.586 mmol) to the reaction mixture and stir for 30 min;

[0061] 5) Add butyl lithium (1.83 mL, 4.59 mmol) to the reaction mixture and stir for 30 min;

[0062] 6) n-Fluoro-n-(phenylsulfonyl)benzenesulfonamide (2.225 g, 7.06 mmol) was added to the reaction mixture and stirred for 30 min. The cooling bath was removed and the reaction mixture was stirred at room temperature overnight. 200 mL of 1 M HCl was added to the suspension, the organic layer was separated and rinsed with brine, and the resulting mixture was dried over magnesium sulfate. The reaction solution was filtered and concentrated under reduced pressure. The crude mixture was filtered through a silica gel plug using n-hexane as an eluent. The hexane was removed under reduced pressure and the crude product was vacuum distilled at 10 mbar to obtain 3,4-difluoro-2,5-bis(trimethylsilyl)thiophene.

[0063] 3. The third step reaction:

[0064] 1) Bromine (2.2 mL, 42.4 mmol) was added to a solution of 3,4-difluoro-2,5-bis(trimethylsilyl)thiophene (5.103 g, 19.29 mmol) in 50 mL of dichloromethane via a syringe pump at a rate of 0.25 mL / min to maintain a gentle reflux.

[0065] 2) after the reaction mixture is completely added, reflux at 50° C. overnight; 3) the reaction solution is poured into 50 mL of saturated aqueous sodium sulfite solution; 4) the reaction mixture is extracted with dichloromethane (3×50 mL); the combined organic phases are washed with 400 mL of 2M sodium sulfite solution, 300 mL of saturated sodium bicarbonate solution, and 300 mL of brine; the combined organic layers are dried over magnesium sulfate; the resulting crude mixture is concentrated under reduced pressure; and finally the crude oil is distilled at 10 mbar to obtain 2,5-dibromo-3,4-difluorothiophene;

[0066] 4. The fourth step reaction

[0067] 1) At room temperature, under a nitrogen atmosphere, a catalytic amount of iodine was added to a mixture of 2-bromothiophene (4.89 g) and magnesium (0.86 g, 36 mmol) in 30 mL of tetrahydrofuran. The mixture was stirred vigorously and allowed to react gradually for about 1 hour, after which the reaction mixture was cooled to room temperature.

[0068] 2) 2,5-Dibromothiophene (2.42 g) and Pd2(dppf)2 (82 mg, 0.1 mmol) were added to the reaction mixture, and the reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was refluxed for another 4 hours, and the reaction mixture was cooled to room temperature;

[0069] 3) Water was added to the reaction mixture, followed by the addition of dilute hydrochloric acid (6M HCl) to quench the reaction until a neutral solution was obtained. The reaction mixture was poured into a large amount of water and extracted with dichloromethane (3×50 mL). The organic layer was dried over anhydrous Na2SO4 and evaporated to a solid organic layer. The crude product was purified by silica gel column chromatography using 4:1 petroleum ether / dichloromethane as the eluent. The preparation process is as follows:

[0070]

[0071] The FEDE derivative of chemical formula (2) is obtained. The preparation of the FEDE derivative adopts a similar method as above.

[0072] Organic solar cells are prepared using the FEDE (1) of the chemical formula (1) prepared above, as well as the FEDE derivative (2) of the chemical formula (2), the FEDE derivative (3) of the chemical formula (3), and the FEDE derivative (4) of the chemical formula (4).

[0073] Example 1

[0074] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0075] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PM6, organic electron acceptor Y6+0.5%CN+1%FEDE derivative (2), cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 1 As shown in the left picture.

[0076] 1) Preparation of a transparent conductive anode substrate: A glass substrate and a substrate composed of a transparent conductive anode ITO were ultrasonically cleaned for 15 minutes using isopropyl alcohol, a detergent solution, three times deionized water, and isopropyl alcohol, respectively. The substrate was then placed in an oven to dry. The transparent anode ITO surface was then irradiated under an ozone-UV lamp for 15 minutes, covered with a watch glass, and removed.

[0077] 2) Preparation of the anode interface: Dissolve 5.40 mg of 2PACz in a small reagent vial, pipette 2000 μL of anhydrous ethanol into the vial, secure the cap with disposable tape, and place in a magnetic heater. Heat at 50°C and 100 rpm for 0.5–1 h.

[0078] The hole transport layer was formed by spin coating 2PACz solution on the transparent conductive ITO surface of the battery substrate at a speed of 3000 rpm for 30 seconds and then annealing at 100°C for 10 minutes.

[0079] 3) Preparation of the organic electron donor: 3.60 mg of the active layer donor PM6 was placed in a small reagent bottle and dissolved in 300 μL of pure chlorobenzene as a solvent to a concentration of 12 mg / mL. The bottle cap was tightly wrapped with disposable tape and placed in a magnetic heater. The solution was heated at 65°C and 130 rpm for 3 hours. The PM6 solution was then spin-coated on the surface of the hole transport layer to form the active layer donor.

[0080] 4) Preparation of organic electron acceptor: 0.90 mg of active layer acceptor Y6 was placed in a small reagent bottle, and 100 μL of chloroform + 0.5% CN + 1% FEDE derivative (2) was added to dissolve the solution to prepare a 9 mg / mL solution. The bottle cap was tightly wrapped with disposable tape and placed in a magnetic heater. The solution was heated at 50°C and 100 rpm for 1.5 hours. The Y6 small molecule acceptor solution was spin-coated on the surface of the PM6 active layer donor to form a double-layer active layer.

[0081] After spin coating, place the watch glass containing the device in a vacuum box for half an hour. After the vacuum is completed, take it out and place it in a magnetic heater for annealing at 100°C for 10 minutes.

[0082] 5) Cathode Interface Preparation: Dissolve 2.00 mg of PDINN in a small reagent bottle and dissolve the solid PDINN in 2000 μL of pure methanol to a 1 mg / mL solution. Cap the bottle and stir until completely dissolved. Wrap the solution in tin foil and store in a dark place. Spin-coat the PDINN solution onto the annealed active layer of the bilayer structure as an electron transport layer.

[0083] After spin coating, use clean tweezers to scratch a neat line with a width of 1 mm on the left edge of the battery active layer surface;

[0084] 6) Preparation of cathode electrode: After the scraping is completed, the surface dish containing the sample is transferred into the evaporation machine to be coated with 100nm thick silver as the battery cathode. The vacuum degree of vacuum evaporation is controlled to 5×10 -4 Pa, a silver electrode with a thickness of 100 nm is formed on the surface of the electron transport layer, and the evaporation rate of the silver electrode is controlled to be 0.01 nm / s when the thickness is 0-5 nm, 0.02 nm / s when the thickness is 5-10 nm, less than 0.05 nm / s when the thickness is 10-20 nm, less than 0.1 nm / s when the thickness is 20-35 nm, and less than 0.35 nm / s when the thickness is 35-100 nm;

[0085] 7) Measure battery efficiency, such as Figure 5 As shown, the highest conversion efficiency is 16.73% and the fill factor is 75.62%.

[0086] Example 2

[0087] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0088] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PBDB-T, organic electron acceptor ITIC+0.5%CN+1%FEDE(1), cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 2 As shown in the left picture.

[0089] 1) Preparation of the transparent conductive anode substrate is the same as in Example 1;

[0090] 2) Preparation of the anode interface is the same as in Example 1;

[0091] 3) Preparation of the organic electron donor: 1.28 mg of the active layer donor PBDB-T was placed in a small reagent bottle and dissolved in 160 μL of pure chlorobenzene to a concentration of 8 mg / mL. The bottle cap was tightly wrapped with disposable tape and placed in a magnetic heater. Heated at 65°C and 130 rpm for 3 hours, the PBDB-T solution was spin-coated on the hole transport layer to form the active layer donor.

[0092] 4) Preparation of organic electron acceptor: 0.90 mg of active layer acceptor ITIC was placed in a small reagent bottle, and 100 μL of chloroform + 0.5% CN + 1% FEDE (1) was added to dissolve the solution to a concentration of 9 mg / mL. The bottle cap was tightly wrapped with disposable tape and placed in a magnetic heater. The solution was heated at 50°C and 100 rpm for 1.5 hours. The ITIC small molecule acceptor solution was spin-coated on the surface of the PBDB-T active layer donor to form a double-layer active layer.

[0093] After spin coating, place the watch glass containing the device in a vacuum box for half an hour. After the vacuum is completed, take it out and place it in a magnetic heater for annealing at 100°C for 10 minutes.

[0094] 5) Preparation of cathode interface is the same as in Example 1;

[0095] 6) The cathode electrode was prepared in the same manner as in Example 1;

[0096] 7) Measure battery efficiency, such as Figure 6 As shown, the highest conversion efficiency is 7.53% and the fill factor is 58.8%.

[0097] Example 3

[0098] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0099] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PM6, organic electron acceptor PYF-T-o+0.5%CN+1%FEDE derivative (3), cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 3 As shown in the left picture.

[0100] 1) Preparation of the transparent conductive anode substrate is the same as in Example 1;

[0101] 2) Preparation of the anode interface is the same as in Example 1;

[0102] 3) Preparation of organic electron donor is the same as in Example 1;

[0103] 4) Preparation of organic electron acceptor: 0.90 mg of active layer acceptor PYF-To was placed in a small reagent bottle, and 100 μL of chloroform + 0.5% CN + 1% FEDE derivative (3) was added to dissolve the acceptor to prepare a solution with a concentration of 9 mg / mL. The bottle cap was tightly wrapped with disposable tape and placed in a magnetic heater. The solution was heated at 50°C and 100 rpm for 1.5 hours. The PYF-To polymer acceptor solution was spin-coated on the surface of the PM6 active layer donor to form a double-layer active layer.

[0104] After spin coating, place the watch glass containing the device in a vacuum box for half an hour. After the vacuum is completed, take it out and place it in a magnetic heater for annealing at 100°C for 10 minutes.

[0105] 5) Preparation of cathode interface is the same as in Example 1;

[0106] 6) The cathode electrode was prepared in the same manner as in Example 1;

[0107] 7) Measure battery efficiency, such as Figure 7 As shown, the highest conversion efficiency is 8.75% and the fill factor is 55.5%.

[0108] Example 4

[0109] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0110] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PM6, organic electron acceptor PYF-T-o+0.5%CN+1%FEDE derivative (4), cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 4 As shown in the left picture.

[0111] 1) Preparation of the transparent conductive anode substrate is the same as in Example 1;

[0112] 2) Preparation of the anode interface is the same as in Example 1;

[0113] 3) Preparation of organic electron donor is the same as in Example 1;

[0114] 4) Preparation of organic electron acceptor: 0.90 mg of active layer acceptor IT-4F was placed in a small reagent bottle, and 100 μL of chloroform + 0.5% CN + 1% FEDE derivative (4) was added to dissolve the acceptor to prepare a solution with a concentration of 9 mg / mL. The bottle cap was tightly wrapped with disposable tape and placed in a magnetic heater. The solution was heated at 50°C and 100 rpm for 1.5 hours. The IT-4F small molecule acceptor solution was spin-coated on the surface of the PM6 active layer donor to form a double-layer active layer.

[0115] After spin coating, place the watch glass containing the device in a vacuum box for half an hour. After the vacuum is completed, take it out and place it in a magnetic heater at 100°C for annealing for 10 minutes.

[0116] 5) Preparation of cathode interface is the same as in Example 1;

[0117] 6) The cathode electrode was prepared in the same manner as in Example 1;

[0118] 7) Measure battery efficiency, such as Figure 8 As shown, the highest conversion efficiency is 11.79% and the fill factor is 74.7%.

[0119] Comparative Example 1

[0120] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0121] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PM6, organic electron acceptor Y6+0.5%CN, cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 1 As shown in the right figure;

[0122] Comparative Example 1 is the control group of Example 1, in which the solid molecular additive FEDE derivative (2) is not added to the organic electron acceptor, and the rest is the same as Example 1;

[0123] The battery efficiency results of Example 1 and Comparative Example 1 are as follows: Figure 5 As shown in the figure, it can be seen that the device of Example 1 with the addition of solid molecular additives has higher efficiency, and the fill factor and short-circuit current are both higher than those of Comparative Example 1.

[0124] Comparative Example 2

[0125] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0126] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PBDB-T, organic electron acceptor ITIC+0.5%CN, cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 2 As shown in the right figure;

[0127] Comparative Example 2 is the control group of Example 2, in which the solid molecular additive FEDE (1) is not added to the organic electron acceptor, and the rest is the same as Example 2.

[0128] The battery efficiency results of Example 2 and Comparative Example 2 are as follows: Figure 6 As shown in the figure, it can be seen that the efficiency of the device in Example 2 with the addition of solid molecular additives is higher than that of Comparative Example 2, and the fill factor and short-circuit current are also better than those of Comparative Example 2.

[0129] Comparative Example 3

[0130] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0131] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PM6, organic electron acceptor PYF-T-o+0.5% CN, cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 3 As shown in the right figure;

[0132] Comparative Example 3 is the control group of Example 3, in which the solid molecular additive FEDE derivative (3) is not added to the organic electron acceptor, and the rest is the same as Example 3.

[0133] The battery efficiency results of Example 3 and Comparative Example 3 are as follows: Figure 7 As shown in the figure, it can be seen that the short-circuit current, fill factor and device conversion efficiency of Example 3 are all better than those of Comparative Example 3.

[0134] Comparative Example 4

[0135] An organic solar cell with a specific vertical distribution morphology and its preparation:

[0136] On the transparent conductive anode substrate ITO, the anode interface 2PACz, organic electron donor PM6, organic electron acceptor PYF-T-o+0.5% CN, cathode interface PDINN and cathode electrode Ag are spin-coated from bottom to top. The battery structure is as follows: Figure 4 As shown in the right figure;

[0137] Comparative Example 4 is the control group of Example 4, in which the solid molecular additive FEDE derivative (4) is not added to the organic electron acceptor, and the rest is the same as Example 4.

[0138] The battery efficiency results of Example 4 and Comparative Example 4 are as follows: Figure 8 As shown in the figure, it can be seen that the filling factor of the device in Example 4 with the addition of solid molecular additives is significantly higher than that in Comparative Example 4, and its efficiency is better.

[0139] As can be seen from the above, the organic solar cell prepared by the present invention has a specific vertical distribution morphology. By adding both a solvent additive and a solid molecular additive to the non-fullerene acceptor solution, the device modified with both liquid and solid molecular additives exhibits higher device performance than the device with only the solvent additive. The device, fabricated using a layer-by-layer processing method, possesses a photoactive layer with an ideal specific vertical distribution structure, resulting in improved photovoltaic performance. By continuously depositing electron donors and acceptors through LBL thin films, the interdiffusion between the donor and acceptor improves charge transport balance, reduces bimolecular charge recombination, and results in a device with better film morphology and less charge recombination.

Claims

1. An organic solar cell with a specific vertical distribution morphology, characterized in that: The device structure of the organic solar cell includes: a transparent conductive anode substrate, an anode interface, an organic electron donor, an organic electron acceptor, a cathode interface and a cathode electrode; The organic electron donor includes one or more polymer electron donor materials; The organic electron acceptor includes a solvent additive and a solid molecular additive; The solvent additive includes one or more of 1,8-diiodooctane and chloronaphthalene; The solid molecular additive includes one or more of 2,2':5',2''-terthiophene and its derivatives, and the chemical structure of the 2,2':5',2''-terthiophene and its derivatives includes the following: 、 、 、 、 、 、 。 2. The organic solar cell according to claim 1, wherein The 2,2':5',2''-terthiophenes also include other structures in which any position on the 2,2':5',2''-terthiophene is substituted by one or more of fluorine atoms, chlorine atoms and bromine atoms.

3. The organic solar cell according to claim 1, wherein The amount of the solvent additive and the solid molecular additive is 0.1-1.5% of the organic electron acceptor.

4. The organic solar cell according to claim 1, wherein In the device structure, the material of the transparent conductive anode substrate includes ITO, the material of the anode interface includes 2PACz, the material of the organic electron acceptor includes one or more non-fullerene donor materials, the material of the cathode interface includes PDINN, and the material of the cathode electrode includes Ag.

5. A method for preparing an organic solar cell having a specific vertical distribution morphology according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: on a transparent conductive anode substrate, sequentially spin-coating an anode interface, an organic electron donor, an organic electron acceptor, a cathode interface and a cathode electrode from bottom to top.

6. The method for preparing an organic solar cell with a specific vertical distribution morphology according to claim 5, wherein: The organic electron donor is prepared by dissolving a polymer donor material in pure chlorobenzene to prepare a solution with a concentration of 6-12 mg / mL, heating and stirring at 60-70°C and 120-140 rpm for 2-4 hours, and then spin-coating the solution on the anode interface to a thickness of 50-80 nm.

7. The method for preparing an organic solar cell with a specific vertical distribution morphology according to claim 5, wherein: The organic electron acceptor is prepared by spin-coating a non-fullerene acceptor on an organic electron donor to obtain a double-layer structure, placing the structure in a vacuum box for 30 minutes, and then annealing the structure at 100-120° C. for 8-10 minutes.

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