Preparation method of an organic solar cell and an organic solar cell

Abstract

The present invention is applicable to the technical field of organic solar cells, and provides a preparation method of an organic solar cell and the organic solar cell. The preparation method of the organic solar cell includes: Step S1: Cleaning, drying, and performing surface treatment on a substrate with a transparent conductive cathode layer attached to its surface; Step S2: Preparing an electron transport layer on the transparent conductive cathode layer; Step S3: Heating the active layer solution to 50 - 130 °C, continuously heating for a certain period of time under the condition of 50 - 130 °C, and then rapidly spin-coating the heated active layer solution on the electron transport layer to obtain an active layer; Step S4: Sequentially preparing a hole transport layer and a metal anode layer on the active layer. The preparation method of the organic solar cell of the present invention simplifies the preparation process by heating the active layer solution and rapidly spin-coating the heated active layer solution to prepare the active layer. The preparation of the active layer does not require complex annealing treatment, which is conducive to large-scale production and improves the cell efficiency of the organic solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of organic solar cells, and particularly relates to a preparation method of an organic solar cell and an organic solar cell. Background Art

[0002] Solar cells have gone through a development process from the first-generation silicon-based solar cells mainly composed of single-crystalline silicon and polycrystalline silicon, to the second-generation thin-film solar cells mainly composed of copper indium gallium selenide (CIGS), cadmium telluride (CdTe), gallium arsenide (GaAs), etc., and then to the third-generation solar cells mainly composed of dye-sensitized, quantum dots, perovskites, and organic materials. Currently, the most mature representative of solar cells is single-crystalline silicon solar cells. However, its complex preparation process, strict requirements for raw materials, high cost, and environmental pollution caused by the processing process limit its further development. In contrast, organic solar cells have become a research hotspot in the current solar cell field due to their unique advantages such as light weight, flexibility, semi-transparency, and solution processability.

[0003] Among them, the active layer, as the most important component of an organic solar cell, is the place where the photoelectric conversion process occurs. The working efficiency of an organic solar cell is closely related to the microscopic morphology of the active layer. The current main methods for optimizing the morphology of the active layer are solvent additives, thermal annealing, and solvent vapor annealing. However, the boiling points of solvent additives are generally high and it is difficult to remove them under the subsequent thermal annealing conditions of the active layer. During the long-term storage of organic solar cells, these residual solvent additives will damage the morphology of the active layer, causing a significant attenuation in the performance of organic solar cells. However, both thermal annealing and solvent vapor annealing are carried out after the preparation of the active layer, with strict requirements for the temperature of thermal annealing and the annealing solvent, making it difficult to ensure the repeatability of organic solar cells, and the annealing process is relatively complex; moreover, for receptor materials with strong crystallinity, additional annealing will instead make the phase separation size of the blend film too large, which is not conducive to the efficient transmission of charges, resulting in a low efficiency of organic solar cells. Summary of the Invention

[0004] The present invention provides a preparation method of an organic solar cell, aiming to solve the problems in the existing organic solar cells that the preparation of the active layer requires annealing, resulting in a complex preparation process and low efficiency of organic solar cells due to the unfavorable efficient transmission of charges.

[0005] The present invention is implemented as follows. A preparation method of an organic solar cell is provided, including the following steps:

[0006] Step S1: Clean, dry, and perform surface treatment on a substrate with a transparent conductive cathode layer attached to its surface;

[0007] Step S2: preparing an electron transport layer on the transparent conductive cathode layer;

[0008] Step S3: heating the active layer solution to 50-130° C. and continuously heating at 50-130° C. for a certain period of time, and then rapidly spin-coating the heated active layer solution on the electron transport layer to obtain an active layer;

[0009] Step S4: sequentially preparing a hole transport layer and a metal anode layer on the active layer.

[0010] Preferably, in step S3, the active layer solution is heated to 50-70° C. and continuously heated at 50-70° C. for a certain period of time.

[0011] Preferably, in step S3, the continuous heating time is 5 to 30 minutes.

[0012] Preferably, in step S1, cleaning the substrate with the transparent conductive cathode layer attached to the surface includes:

[0013] The substrate with the transparent conductive cathode layer attached to the surface is ultrasonically cleaned for 15 to 20 minutes using a cleaning agent, deionized water, acetone, and isopropyl alcohol in sequence.

[0014] Preferably, the surface treatment is plasma surface treatment, and the surface treatment time is 3 to 5 minutes.

[0015] Preferably, in step S2, preparing an electron transport layer on the transparent conductive cathode layer includes:

[0016] The ZnO precursor solution is spin-coated on the transparent conductive cathode layer at a spin-coating speed of 3000-4000 rpm and a spin-coating time of 30-45 seconds. The substrate on which the ZnO precursor solution is spin-coated is annealed.

[0017] Preferably, the annealing temperature is 150-200° C., and the annealing time is 30-60 minutes.

[0018] Preferably, the step S3 further includes:

[0019] Preparation of active layer solution: Dissolve the donor material and the acceptor material in a mass ratio of 1:1 to 1:1.5 in chloroform or chlorobenzene solvent, and stir thoroughly to obtain an active layer solution with a total concentration of the donor material and the acceptor material of 10 to 25 mg / mL.

[0020] Preferably, the donor material in the active layer is PM6, and the acceptor material in the active layer is BTP-eC9.

[0021] Preferably, the thickness of the active layer is 70 to 140 nm.

[0022] Preferably, step S4 includes:

[0023] On the surface of the active layer, the hole transport layer and the metal anode layer are sequentially obtained by vacuum evaporation.

[0024] The present invention also provides an organic solar cell, which is prepared by the above preparation method.

[0025] The preparation method of the organic solar cell provided by the present invention has the following technical effects:

[0026] (1) By heating the active layer solution to 50-130 °C and continuously heating for a certain time at 50-130 °C, and then quickly spin-coating to form the active layer, the heating temperature is easy to control, the repeatability of the organic solar cell is good, and the preparation of the active layer does not require additional annealing treatment, so that the morphology of the active layer can be effectively regulated, the preparation process is simplified, and large-scale production is facilitated;

[0027] (2) The method of preparing the active layer by thermal spin-coating of the present invention can effectively reduce the surface roughness of the blend film, thereby suppressing the aggregation of the electron acceptor, making the interpenetrating network structure of the donor and acceptor more uniform and obvious, and the charge transport more balanced, thus effectively improving the performance of the organic solar cell and increasing the efficiency of the organic solar cell;

[0028] (3) The method of preparing the active layer by thermal spin-coating provided by the present invention, based on PM6:BTP-eC9 as the active layer, compared with the organic solar cell prepared by the traditional method without using the thermal spin-coating method for the active layer, the organic solar cell prepared by the preparation method of the organic solar cell of the present invention has a PCE value of 17.5%, and the battery efficiency is increased by nearly 15%. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of an organic solar cell provided by an embodiment of the present invention;

[0030] Figure 2 It is a molecular structure diagram of a donor material used in an organic solar cell provided by an embodiment of the present invention;

[0031] Figure 3 It is a molecular structure diagram of an acceptor material used in an organic solar cell provided by an embodiment of the present invention;

[0032] Figure 4 It is a flowchart of a preparation method of an organic solar cell provided by an embodiment of the present invention;

[0033] Figure 5J-V curves of the organic solar cell prepared by the preparation method of Example 1 provided by the present invention and the organic solar cell prepared by Comparative Example 1;

[0034] Figure 6 TEM image of the active layer prepared in Example 1 provided by the present invention;

[0035] Figure 7 TEM image of the active layer prepared in Comparative Example 1. Detailed implementation manners

[0036] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] A preparation method of an organic solar cell provided by an embodiment of the present invention includes heating an active layer solution to 50-130°C and continuously heating it at 50-130°C for a certain period of time, and then quickly spin-coating it into an active layer. The heating temperature is easy to control, so that the repeatability of the organic solar cell is good. The preparation of the active layer does not require additional annealing treatment, and the effective regulation of the active layer morphology can be achieved, which simplifies the preparation process and is conducive to large-scale production. Moreover, heating the active layer solution before spin-coating can effectively reduce the surface roughness of the blend film, thereby suppressing the aggregation of electron acceptors, making the interpenetrating network structure of the donor and acceptor more uniform and obvious, and the charge transport more balanced, thus effectively improving the performance of the device. Compared with the organic solar cell whose active layer is not prepared by the hot spin-coating method, the cell efficiency can be increased by nearly 15%.

[0038] Please refer to Figure 1 , an organic solar cell provided by an embodiment of the present invention includes a substrate 1, a transparent conductive cathode layer 2, an electron transport layer 3, an active layer 4, a hole transport layer 5 and a metal anode layer 6 which are arranged in sequence from bottom to top.

[0039] In an embodiment of the present invention, the substrate 1 serves as the support basis of the organic solar cell device and is made of a transparent material, such as glass, metal, silicon, plastic or organic synthetic material with light-transmitting properties.

[0040] As an embodiment of the present invention, the substrate is glass, and the transparent conductive cathode layer is an ITO film; the material of the electron transport layer is ZnO, and the thickness of the electron transport layer is 30-40 nm. The material of the hole transport layer is MoO3, and the thickness is 5-15 nm. The material of the metal anode layer is Ag, Al, Au or Cu, and the thickness of the metal anode layer is 100-150 nm.

[0041] As an embodiment of the present invention, the donor material in the active layer is one or any combination of PTB1, PTB7, PBDTT-E-T, PTB7-Th, PBDB-T, PM6, PM7, FTAZ, PTQ10, or D18; the acceptor material is one or a combination of more than one of INPIC-4F, INPIC-4CL, m-INPOIC, IPT-2F, IPTT-2F, M3, M4, M34, Y6, L8-BO, BTP-eC9. Among them, the molecular structures of PTB1, PTB7, PBDTT-E-T, PTB7-Th, PBDB-T, PM6, PM7, FTAZ, PTQ10, D18 are as Figure 2 shown, and the molecular structures of INPIC-4F, INPIC-4CL, m-INPOIC, IPT-2F, IPTT-2F, M3, M4, M34, Y6, L8-BO, BTP-eC9 are as Figure 3 shown.

[0042] As a preferred embodiment of the present invention, the donor material in the active layer 4 is PM6, and the acceptor material in the active layer 4 is BTP-eC9. In this embodiment, PM6 as the donor material and BTP-eC9 as the acceptor material have the best energy level matching, which is conducive to the collection of carriers, can minimize the voltage loss, and thus improve the conversion efficiency of the organic solar cell.

[0043] Please refer to Figure 4 , the embodiment of the present invention provides a preparation method of an organic solar cell for preparing the above-mentioned organic solar cell, including the following steps:

[0044] Step S1: Clean, dry, and perform surface treatment on the substrate 1 with the transparent conductive cathode layer 2 attached to its surface;

[0045] In step S1, the transparent conductive cathode layer 2 can be prepared on the substrate 1 first, or the substrate 1 with the transparent conductive cathode layer 2 prepared on its surface can be directly purchased from the market for the preparation of the organic solar cell.

[0046] As an embodiment of the present invention, in step S1, the cleaning of the substrate 1 with the transparent conductive cathode layer 2 attached to its surface includes:

[0047] Ultrasonically clean the substrate 1 with the transparent conductive cathode layer 2 attached to its surface with a cleaning agent, deionized water, acetone, and isopropanol for 15-20 minutes in sequence.

[0048] In this embodiment, by successively cleaning the substrate 1 with a cleaning agent, deionized water, acetone, and isopropyl alcohol, which has a transparent conductive cathode layer 2 attached to its surface, impurities can be effectively removed, ensuring the smooth progress of subsequent preparation processes of the organic solar cell and ensuring the good performance of the battery.

[0049] As an embodiment of the present invention, the surface treatment is plasma surface treatment, and the time of the surface treatment is 3 to 5 minutes. By using plasma surface treatment, the surface wettability and work function of the transparent conductive cathode layer 2 are optimized.

[0050] Step S2: Prepare an electron transport layer 3 on the transparent conductive cathode layer 2;

[0051] As an embodiment of the present invention, in step S2, preparing the electron transport layer 3 on the transparent conductive cathode layer 2 includes:

[0052] Spin-coat the ZnO precursor solution on the transparent conductive cathode layer 2 at a spin speed of 3000 - 4000 rpm for 30 - 45 s, and then anneal the substrate 1 coated with the ZnO precursor solution.

[0053] Among them, the ZnO precursor solution is prepared by a conventional method in the prior art. For example, the preparation of the ZnO precursor solution specifically includes: weighing appropriate volumes of zinc acetate and ethanolamine and dissolving them in an appropriate volume of 2-methoxyethanol solution, and stirring at room temperature for 3 - 6 h to prepare the ZnO precursor solution.

[0054] In step S2, the annealing temperature is 150 - 200 °C and the annealing time is 30 - 60 minutes, which can ensure the formation of a good electron transport layer 3.

[0055] Step S3: Heat the active layer 4 solution to 50 - 130 °C and continuously heat it at 50 - 130 °C for a certain time, and then quickly spin-coat the heated active layer 4 solution on the electron transport layer 3 to obtain the active layer 4;

[0056] In step S3, the specific heating temperature of the active layer solution can be flexibly set according to the actual situation. For example, the active layer solution can be heated to 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, etc.

[0057] In the embodiments of the present invention, by first heating the active layer solution to 50-130°C, the acceptor materials in the active layer solution are rapidly mixed. The heating temperature is easy to control, which is conducive to forming a network interpenetrating structure of nanofibers. After the heating of the active layer solution is completed, it is quickly spin-coated into an active layer. During the rapid spin-coating process, the hot active layer solution can cause the acceptor molecules to rapidly crystallize, thereby effectively suppressing the excessive self-aggregation phenomenon of the acceptor molecules, obtaining a more ideal blend film morphology, enabling efficient charge transport, and thus improving the battery efficiency. Moreover, it replaces the traditional annealing process after spin-coating the active layer solution. The heating temperature is easy to control, the repeatability of the organic solar cell is good, and the preparation of the active layer does not require additional annealing treatment to effectively regulate the morphology of the active layer, simplifies the preparation process, and is conducive to large-scale production.

[0058] In the embodiments of the present invention, the method for preparing the active layer by thermal spin-coating can effectively reduce the surface roughness of the blend film, thereby suppressing the aggregation of electron acceptors, making the interpenetrating network structure of the donor-acceptor more uniform and obvious, and the charge transport more balanced, thus effectively improving the performance of the organic solar cell and increasing the efficiency of the organic solar cell.

[0059] In the embodiments of the present invention, based on PM6:BTP-eC9 as the active layer, compared with the traditional organic solar cell whose active layer is not prepared by the thermal spin-coating method, the organic solar cell prepared by the preparation method of the present invention has achieved a PCE value of 17.5%, and the efficiency has increased by nearly 15%.

[0060] As a preferred embodiment of the present invention, the solvent of the active layer solution is chlorobenzene or chloroform. The solvent of the active layer solution can be selected according to the actual situation. Of course, other solvents can also be selected for the solvent of the active layer solution.

[0061] As an embodiment of the present invention, in step S3, the active layer solution is heated to 50-70°C and continuously heated for a certain time at 50-70°C. This can make the heating temperature as close as possible to the boiling point of the solvent in the active layer solution, which can better ensure the quality of molecular crystallization in the hot active layer solution, and further improve the charge transport performance.

[0062] In practical applications, the heating temperature of the active layer solution can be determined according to the boiling point of the solvent in the active layer solution. For example, when the solvent of the active layer solution is chloroform, the heating temperature of the active layer solution is preferably 65°C; when the solvent of the active layer solution is chlorobenzene, the heating temperature of the active layer solution is preferably 130°C. In this way, the quality of molecular crystallization in the hot active layer solution can be ensured, and the charge transport performance can be improved.

[0063] As a preferred embodiment of the present invention, in step S3, the heating time is 5 to 30 minutes.

[0064] In this embodiment, by combining a heating time of 5 to 30 minutes with a heating temperature of the active layer solution of 50 to 130° C., the crystallization speed and quality of the active layer 4 can be controlled as much as possible, effectively ensuring the charge transfer performance of the prepared active layer 4.

[0065] In step S3, the active layer solution is continuously heated for any time between 5 and 30 minutes. For example, it can be 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, etc. Of course, the active layer solution can be continuously heated for any other time.

[0066] As an embodiment of the present invention, step S3 further includes:

[0067] Preparation of active layer solution: Dissolve the donor material and the acceptor material in a mass ratio of 1:1 to 1:1.5 in chloroform or chlorobenzene solvent, and stir thoroughly to obtain an active layer solution with a total concentration of the donor material and the acceptor material of 10 to 25 mg / mL.

[0068] In this embodiment, by setting the mass ratio of the donor material to the acceptor material to a reasonable range of 1:1 to 1:1.5, the active layer 4 prepared from the active layer solution can have good charge transfer performance.

[0069] As an embodiment of the present invention, the donor material in the active layer 4 is PM6, and the acceptor material in the active layer 4 is BTP-eC9.

[0070] In this embodiment, since PM6 as a donor material and BTP-eC9 as an acceptor material have good energy level matching, it is beneficial to the collection of carriers and can minimize voltage loss, thereby improving the conversion efficiency of the prepared organic solar cell.

[0071] As one embodiment of the present invention, the thickness of the active layer 4 is 70 to 140 nm. The thickness of the active layer 4 can be set to any value between 70 and 140 nm. For example, the thickness of the active layer 4 can be set to 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, 130 nm, or 140 nm.

[0072] In this embodiment, by controlling the thickness of the active layer 4 to be 70-140 nm, good charge transfer performance of the flexible organic solar cell can be ensured and the processing of the active layer 4 can be facilitated.

[0073] Step S4: sequentially preparing a hole transport layer 5 and a metal anode layer 6 on the active layer 4 .

[0074] As an embodiment of the present invention, step S4 includes:

[0075] On the surface of the active layer 4, a hole transport layer 5 and a metal anode layer 6 are sequentially obtained by vacuum evaporation.

[0076] In this embodiment, the hole transport layer 5 and the metal anode layer 6 are obtained by vacuum evaporation, which facilitates the preparation of the hole transport layer 5 and the metal anode layer 6.

[0077] To further prove the technical effects achieved by the present invention, Example 1 and Comparative Example 1 are carried out for verification. Among them, Example 1 adopts the preparation method of the organic solar cell provided by the present invention, and Comparative Example 1 uses the preparation method of the traditional organic solar cell.

[0078] Example 1

[0079] Step S1: The transparent conductive glass with the ITO transparent conductive cathode layer 2 attached to its surface is sequentially cleaned with glass cleaning agent, deionized water, acetone and isopropanol under ultrasonic conditions, and the ultrasonic time for each step is 15 min; the cleaned ITO glass is dried with a nitrogen gun and then placed in a vacuum plasma machine for 3 min;

[0080] Step S2: 1 g of zinc acetate dihydrate particles and 0.28 g of ethanolamine are dissolved in 10 mL of 2-methoxyethanol solution, and stirred at room temperature for 5 h to prepare a ZnO precursor solution; then the ZnO precursor solution is uniformly spin-coated on the surface of the ITO glass, spin-coated at a speed of 5000 rpm for 30 s, and then the substrate 1 with the spin-coated ZnO precursor solution is placed on a heating table at 200 °C for annealing for 1 h to obtain a ZnO electron transport layer 3;

[0081] Step S3: The preparation of the active layer 4 is completed in a glove box filled with nitrogen. The preparation method of the active layer solution is as follows: the donor material PM6 and the acceptor material BTP-eC9 are dissolved in chloroform solvent, with a total concentration of 15 mg / mL, and the mass ratio of the donor to the acceptor is 1:1.2. The blend solution is stirred at room temperature for 12 h to completely dissolve it. Before spin-coating, the active layer 4 solution is heated to 65 °C and continuously heated at 65 °C for 10 min, and then the heated mixed solution is quickly spin-coated on the ZnO electron transport layer 3 at a spin-coating speed of 3000 rpm and a spin-coating time of 30 s;

[0082] Step S4: The hole transport layer 5 and the metal anode layer 6 are prepared by vacuum evaporation: the hole transport layer 5 and the metal anode layer 6 are respectively at a low pressure of below 5×10 -4 Pa and Deposited at a rate of, the thicknesses of the hole transport layer 5 and the metal anode layer 6 are 10 nm and 150 nm respectively, and the effective area of the obtained organic solar cell is 3.97 mm 2 .

[0083] Comparative Example 1

[0084] The preparation method of the organic solar cell in Comparative Example 1 uses the traditional preparation method of organic solar cells. Compared with Example 1 in the preparation process, only the preparation method of the active layer 4 in step S3 is different, and the remaining steps remain unchanged.

[0085] Among them, the preparation process of the active layer 4 in Comparative Example 1 is as follows: The donor material PM6 and the acceptor material BTP-eC9 are dissolved in chloroform solvent, with a total concentration of 15 mg / mL, and the mass ratio of the donor to the acceptor is 1:1.2. The blend solution is stirred at room temperature for 12 h to completely dissolve it, and then the mixed solution is spin-coated on the ZnO electron transport layer 3 at a spin-coating speed of 3000 rpm and a spin-coating time of 30 s.

[0086] Using a spectral distribution of AM1.5G and a light intensity of 100 mw / cm 2 The Oriel 300W solar simulator is used as the light source to test the optoelectronic performance of the organic solar cell prepared in Example 1 and the organic solar cell obtained in Comparative Example 1. The J-V curve is measured through a Keithly2400 digital source meter, as Figure 5 shown, and then the optoelectronic performance test parameters are obtained, as shown in Table 1.

[0087] Table 1: Optoelectronic performance test parameters

[0088]

[0089] As can be seen from Table 1, compared with the organic solar cell in Comparative Example 1 where the active layer was not prepared by the hot spin-coating method, for the organic solar cell obtained in Example 1 with the active layer prepared by hot spin-coating, its open-circuit voltage remains almost unchanged, but its short-circuit current and fill factor are significantly improved. This is because preparing the active layer by the hot spin-coating method can effectively reduce the surface roughness of the blend film, thereby suppressing the aggregation of electron acceptors and significantly improving the performance of the device. Finally, compared with Comparative Example 1, the photoelectric conversion efficiency of the organic solar cell with the active layer prepared by hot spin-coating in Example 1 is increased by nearly 15%.

[0090] To analyze the reason for the better performance of the example, the morphologies of the active layers of Example 1 and Comparative Example 1 were respectively tested by transmission electron microscopy (TEM), as shown in Figure 6 and Figure 7As shown. In contrast, the active layer prepared by the thermal spin-coating method of the present invention has a more uniform and obvious nanofiber interpenetrating network structure, which is beneficial to the efficient dissociation and transport of carriers. Therefore, the corresponding organic solar cell has better photovoltaic performance.

[0091] A method for preparing an organic solar cell provided by an embodiment of the present invention heats an active layer solution to 50-130 °C, continuously heats it for a certain time at 50-130 °C, and then quickly spin-coats it into an active layer. The heating temperature is easy to control, so that the organic solar cell has good repeatability. The preparation of the active layer does not require additional annealing treatment, and the effective regulation of the morphology of the active layer can be achieved, simplifying the preparation process and facilitating large-scale production. Moreover, heating the active layer solution before spin-coating can effectively reduce the surface roughness of the blend film, thereby suppressing the aggregation of electron acceptors, making the interpenetrating network structure of the donor-acceptor more uniform and obvious, and the charge transport more balanced, thus effectively improving the performance of the device. Compared with an organic solar cell whose active layer is not prepared by the thermal spin-coating method, the cell efficiency can be increased by nearly 15%.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing an organic solar cell, characterized in that: The following steps are involved: Step S1: cleaning, drying, and surface treating the substrate with the transparent conductive cathode layer attached to the surface; Step S2: preparing an electron transport layer on the transparent conductive cathode layer; Step S3: heating the active layer solution to 50-130° C., close to the boiling point of the solvent in the active layer solution, and continuously heating at 50-130° C. for a certain time, and then rapidly spin-coating the heated active layer solution on the electron transport layer to obtain the active layer, and the active layer does not require annealing treatment; Step S4: sequentially preparing a hole transport layer and a metal anode layer on the active layer.

2. The method for preparing an organic solar cell according to claim 1, wherein: In step S3, the active layer solution is heated to 50-70° C. and continuously heated at 50-70° C. for a certain period of time.

3. The preparation method of an organic solar cell according to claim 1, wherein, In step S3, the continuous heating time is 5 to 30 minutes.

4. The preparation method of an organic solar cell according to claim 1, characterized in that, In the step S1, cleaning the substrate with the transparent conductive cathode layer attached to the surface includes: The substrate with the transparent conductive cathode layer attached to the surface is ultrasonically cleaned for 15 to 20 minutes using a detergent, deionized water, acetone, and isopropyl alcohol in sequence.

5. The preparation method of an organic solar cell according to claim 1, characterized in that, The surface treatment is plasma surface treatment, and the surface treatment time is 3 to 5 minutes.

6. The method for preparing an organic solar cell according to claim 1, wherein: In the step S2, preparing an electron transport layer on the transparent conductive cathode layer includes: The ZnO precursor solution is spin-coated on the transparent conductive cathode layer at a spin-coating speed of 3000-4000 rpm and a spin-coating time of 30-45 seconds. The substrate on which the ZnO precursor solution is spin-coated is annealed.

7. The preparation method of an organic solar cell according to claim 6, characterized in that, The annealing temperature is 150-200° C., and the annealing time is 30-60 minutes.

8. A method for preparing an organic solar cell according to claim 1, characterized in that, The step S3 further includes: Preparation of active layer solution: Dissolve the donor material and the acceptor material in a mass ratio of 1:1 to 1:1.5 in chloroform or chlorobenzene solvent, and stir thoroughly to obtain an active layer solution with a total concentration of the donor material and the acceptor material of 10 to 25 mg / mL.

9. The preparation method of an organic solar cell according to claim 1, characterized in that, The donor material in the active layer is PM6, and the acceptor material in the active layer is BTP-eC9.

10. A method for preparing an organic solar cell according to claim 1, characterized in that, The thickness of the active layer is 70-140 nm.

11. The preparation method of an organic solar cell according to claim 1, characterized in that, The step S4 comprises: The hole transport layer and the metal anode layer are sequentially formed on the surface of the active layer by vacuum evaporation.

12. An organic solar cell, characterized in that, The organic solar cell is prepared by the preparation method according to any one of claims 1 to 11.

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