Solar cell activation layer, preparation method and application thereof, and solar cell

Abstract

The invention relates to the technical field of solar cell activation layers, in particular to a solar cell activation layer, a preparation method and application thereof and a solar cell. The invention provides a solar cell activation layer. The solar cell activation layer comprises an electron donor, an electron acceptor, a coumarin material and a derivative thereof, the electron donor is a polymer electron donor; and the electron acceptor is a non-fullerene electron acceptor. According to the solar cell activation layer, the problem of high toxicity can be solved by selecting the fenugreek and the derivatives thereof as solid additives, and meanwhile, the fenugreek and the derivatives thereof can interact with a polymer electron donor and a non-fullerene receptor in the activation layer to achieve the purpose of simultaneously regulating and controlling the morphology and the carrier performance of the activation layer.

Description

Technical Field

[0001] This invention relates to the field of solar cell activation layer technology, and more particularly to a solar cell activation layer, its preparation method and application, and solar cells. Background Technology

[0002] Solar energy, as one of the most promising and readily available green renewable energy sources, is inexhaustible. Solution-processed organic solar cells (OSCs) have attracted much attention due to their numerous advantages, including flexibility, low cost, semi-transparency, and the ability to functionalize the absorption and photoelectric properties of the active layer molecules according to practical needs. In recent years, with the rapid development of polymer donor materials and non-fullerene acceptors, and continuous improvements in device technology, the power conversion efficiency (PCE) of single-cell devices has reached 21%.

[0003] In high-efficiency OSCs, complex post-processing is typically required to optimize the arrangement of non-fullerene acceptors and their interaction with polymer donor materials, improve the phase separation size and morphology of the active layer, enhance its carrier transport performance, and thus improve the device's photoelectric conversion efficiency. However, complex post-processing often leads to a series of problems such as poor reproducibility and instability. Solid additives, due to their simple preparation process and the ability to improve the morphology of the active layer and device stability by controlling film formation kinetics and adjusting their interactions with other materials in the active layer, have become catalysts for accelerating the development of OSCs.

[0004] However, most reported solid additives contain halogen atoms, which are highly toxic. Therefore, it is urgent and of great practical significance to develop solid additives with simple structures, non-halogenated nature, and the ability to interact with polymer electron donors and non-fullerene acceptors in the activated layer to simultaneously regulate the morphology and charge carrier properties of the activated layer. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an activation layer for a solar cell, its preparation method and application, and a solar cell. The solar cell activation layer uses coumarin and its derivatives as solid additives to solve the problem of high toxicity, and simultaneously interacts with polymer electron donors and non-fullerene acceptors in the activation layer to achieve the purpose of simultaneously regulating the morphology and carrier performance of the activation layer.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides an activation layer for a solar cell, comprising an electron donor, an electron acceptor, and coumarin and its derivatives; The electron donor is a polymer electron donor; The electron acceptor is a non-fullerene electron acceptor.

[0007] Preferably, the mass ratio of the electron donor to the electron acceptor is 1:(1.1~1.4).

[0008] Preferably, the electron donor includes one or more of PM6, D18, PTQ10, PBDB-T, and D18-Cl.

[0009] Preferably, the electron acceptor includes one or more of L8-BO, Y6, BTP-eC9, AQX-2F, and N3-4F.

[0010] Preferably, the mass ratio of the electron donor to the coumarin and its derivatives is (4~8):(0.8~9.6).

[0011] The present invention also provides a method for preparing the activation layer of the solar cell described in the above technical solution, comprising the following steps: An activation layer solution is obtained by mixing an electron donor, an electron acceptor, coumarin and its derivatives with an organic solvent. In a protective atmosphere, the activation layer solution is coated onto the substrate surface and then annealed to obtain the solar cell activation layer.

[0012] Preferably, the concentration of the electron donor in the activation layer solution is 4~8 mg / mL; The annealing temperature is 90~100℃ and the time is 5~10min.

[0013] The present invention also provides the application of the solar cell activation layer described in the above technical solution or the solar cell activation layer prepared by the preparation method described in the above technical solution in a solar cell.

[0014] The present invention also provides a solar cell, including an activation layer; The activation layer is the solar cell activation layer described in the above technical solution or the solar cell activation layer prepared by the preparation method described in the above technical solution.

[0015] Preferably, it also includes a conductive glass substrate, an anode buffer layer, a cathode buffer layer, and a metal electrode layer; The conductive glass substrate, anode buffer layer, activation layer, cathode buffer layer and metal electrode layer are stacked sequentially.

[0016] This invention provides an activation layer for a solar cell, comprising an electron donor, an electron acceptor, and coumarin and its derivatives; the electron donor is a polymer electron donor; the electron acceptor is a non-fullerene electron acceptor. Coumarin and its derivatives, as solid additives in the activation layer, are chemically stable and inexpensive due to their benzo[a]heterocyclic compound nature, large π-π conjugated system, and lack of toxic halogen atoms, making them green, non-halogenated solid additives. Furthermore, the heterocycles of coumarin contain highly electronegative nitrogen and oxygen atoms, readily forming multiple interactions with the electron donor and / or electron acceptor in the activation layer, thereby controlling the morphology and excited-state properties of the activation layer. This not only broadens the absorption spectrum of the activation layer, enhancing solar energy utilization and increasing photocurrent, but also facilitates the formation of more carrier transport channels, improving carrier mobility, reducing recombination, and increasing the fill factor. In addition, the addition of coumarin and its derivatives can regulate the aggregation and stacking properties between molecules in the activation layer, which is beneficial for obtaining nanoscale phase-separated morphologies, making them a highly promising type of solid additive for solar cells. Therefore, the solar cell activation layer with added coumarin described in this invention has very high versatility and can effectively improve the photoelectric conversion efficiency of solar cells. Attached Figure Description

[0017] Figure 1 Organic solar cells with upright structures as described in Examples 1-6 and Comparative Example 1 J - V Characteristic curves (a), curves showing the changes in short-circuit current and open-circuit voltage with the amount of coumarin added (b), and curves showing the changes in filler factor and photoelectric conversion efficiency with the amount of coumarin added (c). Figure 2 Organic solar cells with upright structures as described in Example 7 and Comparative Example 2 J - V Characteristic curves; Figure 3 Organic solar cells with upright structures as described in Example 8 and Comparative Example 3 J - V Characteristic curves. Detailed Implementation

[0018] This invention provides an activation layer for a solar cell, comprising an electron donor, an electron acceptor, and coumarin and its derivatives; The electron donor is a polymer electron donor; The electron acceptor is a non-fullerene electron acceptor.

[0019] In this invention, the mass ratio of the electron donor to the electron acceptor is preferably 1:(1.1~1.4), more preferably 1:1.1, 1:1.2, 1:1.3 or 1:1.4. In an embodiment of this invention, the mass ratio of the electron donor to the electron acceptor can be 1:1.2. In this invention, the electron donor preferably includes one or more of PM6, D18, PTQ10, PBDB-T, and D18-Cl. When the electron donor is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this invention, the electron donor is specifically PM6 or D18.

[0020] In this invention, the electron acceptor preferably includes one or more of L8-BO, Y6, BTP-eC9, AQX-2F, and N3-4F. When the electron acceptor is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. In the embodiments of this invention, the electron acceptor is specifically L8-BO or Y6.

[0021] In this invention, the coumarin derivative is preferably a compound in which different modification sites are substituted on the benzene ring of coumarin. In this invention, the substituents are preferably one or more of nitro, halogen, cyano, hydroxy, and carboxyl groups, and the halogens are preferably one or more of fluorine, chlorine, bromine, and iodine. When the substituents are two or more of the specific choices mentioned above, this invention does not impose any special limitations on the positional relationship of the substitution sites of the different substituents.

[0022] In this invention, since the benzene ring of coumarin contains multiple modification sites, coumarin derivatives with specific structures and functions can be obtained by substituting different modification sites on the benzene ring of coumarin (for example, introducing alkyl (-R), nitro (-NO2), halogen (-X=F,Cl,Br,I), cyano (-CN), hydroxyl (-OH), ester (-COR), and carboxyl (-COOH) groups onto the benzene ring). The substituents regulate the performance of solar cells by changing the molecular electronic distribution and spatial structure. On the one hand, the substituents adjust the molecular electrostatic potential and dipole moment, regulating and optimizing the charge transfer efficiency to affect the short-circuit current density. J sc) and open circuit voltage ( V On the one hand, it can change the light absorption range and improve light utilization; on the other hand, it can change the interaction mode and site with the donor and acceptor through electrostatic interaction and steric hindrance, thereby optimizing the interface compatibility, reducing charge recombination, and thus achieving the regulation of solar cell performance.

[0023] In this invention, the preferred mass ratio of the electron donor to the coumarin and its derivatives is (4~8):(0.8~9.6), more preferably 7:1.4, 7:2.8, 7:4.2, 5:5, 7:5.6 or 7:8.4.

[0024] In this invention, the coumarin and its derivatives can interact with polymer electron donors and non-fullerene electron acceptors, optimizing the morphology and excited-state performance of the activation layer. This not only broadens the absorption spectrum of the activation layer, enhancing solar energy utilization and increasing photocurrent, but also helps form more carrier transport channels, improving carrier mobility, reducing recombination, and increasing the fill factor. Furthermore, the addition of coumarin has a certain inhibitory effect on intermolecular aggregation in the activation layer, which is beneficial for obtaining nanoscale phase-separated morphologies, making it a very promising organic solid additive for solar cells.

[0025] The present invention also provides a method for preparing the activation layer of the solar cell described in the above technical solution, comprising the following steps: An activation layer solution is obtained by mixing an electron donor, an electron acceptor, coumarin and its derivatives with an organic solvent. In a protective atmosphere, the activation layer solution is coated onto the substrate surface and then annealed to obtain the solar cell activation layer.

[0026] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0027] This invention involves mixing an electron donor, an electron acceptor, coumarin and its derivatives with an organic solvent to obtain an activation layer solution.

[0028] In this invention, the organic solvent preferably includes one or more of chloroform, toluene, and o-xylene. When the organic solvent is two or more of the above-mentioned specific selections, this invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio.

[0029] In this invention, the mixing process preferably involves mixing the electron donor, electron acceptor, and organic solvent before adding coumarin. This invention does not impose any particular limitations on the mixing method or the method of adding the coumarin; any mixing process and addition method well-known to those skilled in the art can be used.

[0030] In this invention, the concentration of electron donor in the activation layer solution is preferably 4-8 mg / mL, more preferably 4 mg / mL, 5 mg / mL, 6 mg / mL, 7 mg / mL, or 8 mg / mL. In an embodiment of this invention, the concentration of electron donor in the activation layer solution is specifically 5 mg / mL or 7 mg / mL.

[0031] After obtaining the activation layer solution, the present invention coats the activation layer solution onto the substrate surface in a protective atmosphere and then anneals it to obtain the solar cell activation layer.

[0032] In this invention, the protective atmosphere is preferably an inert atmosphere, and the inert atmosphere is preferably a nitrogen atmosphere.

[0033] In this invention, the coating method is preferably spin coating, and the spin coating speed is preferably 2500~4000 rpm, more preferably 2500 rpm, 2800 rpm, 3000 rpm, 3300 rpm, 3500 rpm, 3800 rpm, or 4000 rpm; the spin coating time is preferably 25~40 s, more preferably 25 s, 30 s, 35 s, or 40 s. In an embodiment of this invention, the spin coating speed can be 3000 rpm, and the time can be 30 s.

[0034] In this invention, the coating amount is preferably 1.5 cm². 14-17 μL is coated onto a substrate surface with an area of ​​1.5 cm², more preferably onto a substrate with an area of ​​1.5 cm². A coating of 14 μL, 15 μL, 16 μL, or 17 μL is applied to a substrate surface of 1.5 cm. In embodiments of the present invention, the coating amount is specifically defined as the amount applied over an area of ​​[missing information]. 15 μL was coated onto the substrate surface.

[0035] In this invention, the annealing temperature is preferably 90~100℃, more preferably 90℃, 92℃, 94℃, 96℃, 98℃ or 100℃; the annealing time is preferably 5~10min, more preferably 5min, 6min, 7min, 8min, 9min or 10min. In an embodiment of this invention, the annealing temperature can be 90℃ and the annealing time can be 10min.

[0036] The present invention also provides the application of the solar cell activation layer described in the above technical solution or the solar cell activation layer prepared by the preparation method described in the above technical solution in a solar cell.

[0037] In this invention, the solar cell is preferably an organic solar cell; the organic solar cell is preferably an upright organic solar cell or an inverted organic solar cell, more preferably an upright organic solar cell.

[0038] The present invention also provides a solar cell, including an activation layer; The activation layer is the solar cell activation layer described in the above technical solution or the solar cell activation layer prepared by the preparation method described in the above technical solution.

[0039] In this invention, the solar cell preferably further comprises a conductive glass substrate, an anode buffer layer, a cathode buffer layer, and a metal electrode layer; The conductive glass substrate, anode buffer layer, activation layer, cathode buffer layer and metal electrode layer are preferably stacked in sequence.

[0040] This invention does not impose any special limitations on the conductive glass substrate; any substrate well-known to those skilled in the art can be used. In embodiments of this invention, the conductive glass substrate is preferably ITO conductive glass.

[0041] In this invention, the conductive glass substrate is preferably a pretreated conductive glass substrate. The preparation process of the pretreated conductive glass substrate preferably includes: sequentially cleaning, drying, and treating the conductive glass substrate with ultraviolet ozone plasma. In this invention, the cleaning is preferably performed sequentially using a detergent followed by ultrasonic cleaning; the detergent is preferably a detergent solution diluted with deionized water (mass concentration of 0.5%~2%); the ultrasonic cleaning is preferably performed sequentially using deionized water, acetone, and isopropanol, with the ultrasonic cleaning time in each of the three processes preferably being 15 minutes. The drying temperature is preferably 80°C. This invention does not impose any special limitations on the drying time; any time familiar to those skilled in the art can be used. This invention does not impose any special limitations on the conditions for the ultraviolet ozone plasma treatment; any conditions familiar to those skilled in the art can be used. In an embodiment of this invention, the ultraviolet ozone plasma treatment time can be 10 minutes.

[0042] This invention does not impose any special limitations on the composition of the anode buffer layer; any composition well-known to those skilled in the art can be used. In an embodiment of this invention, the material of the anode buffer layer is specifically PEDOT:PSS. In an embodiment of this invention, the preparation process of the anode buffer layer is as follows: a PEDOT:PSS aqueous solution with a mass concentration of 1.3~1.7% is filtered through a 0.22μm aqueous filter membrane; 40μL of the PEDOT:PSS aqueous solution is then spin-coated onto the surface of a conductive glass substrate at 4000rpm for 30s using a pipette; and annealed in air at 155°C for 15min to obtain the anode buffer layer.

[0043] This invention does not impose any special limitations on the composition of the cathode buffer layer; any composition well-known to those skilled in the art can be used. In an embodiment of this invention, the material of the cathode buffer layer is specifically PNDIT-F3N. In an embodiment of this invention, the preparation process of the cathode buffer layer is as follows: PNDIT-F3N is dissolved in methanol to obtain a PNDIT-F3N solution with a concentration of 1 mg / mL. Then, 30 μL of the PNDIT-F3N solution is spin-coated onto the surface of the activation layer at a speed of 4000 rpm for 30 seconds using a pipette to obtain the cathode buffer layer.

[0044] This invention does not impose any special limitations on the material of the metal electrode layer; any material well-known to those skilled in the art can be used. In an embodiment of this invention, the material of the metal electrode layer is specifically Ag, and the metal electrode layer is prepared by vapor deposition, which is performed in a vacuum vapor deposition machine at a vacuum degree of 1×10⁻⁶. -4 Pa, the present invention does not impose any special limitations on the conditions and parameters of the vapor deposition, and conditions and parameters well known to those skilled in the art can be used.

[0045] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] Example 1 A 2% (w / w) detergent solution diluted with deionized water was used to clean ITO conductive glass (1.5cm). After cleaning (1.5cm), the substrate was ultrasonically cleaned with deionized water, acetone and isopropanol for 15 minutes each, dried at 80℃ and treated with ultraviolet ozone plasma for 10 minutes to obtain a pretreated conductive glass substrate. A 1.4% PEDOT:PSS aqueous solution was filtered through a 0.22 μm aqueous filter membrane. 40 μL of the PEDOT:PSS aqueous solution was then spin-coated onto the pretreated conductive glass substrate at 4000 rpm for 30 s. The substrate was then annealed in air at 155 °C for 15 min to obtain the anode buffer layer (10 nm thick). After mixing electron donor PM6, electron acceptor L8-BO and chloroform, coumarin was added to obtain an activation layer solution (PM6 concentration of 7 mg / mL, L8-BO concentration of 8.4 mg / mL, and coumarin concentration of 1.4 mg / mL). Then, 15 μL of the activation layer solution was spin-coated at 3000 rpm for 30 s under a nitrogen atmosphere and annealed at 90 °C for 10 min to obtain an activation layer (thickness of 100 nm). PNDIT-F3N was dissolved in methanol to obtain a PNDIT-F3N solution with a concentration of 1 mg / mL. Then, 30 μL of the PNDIT-F3N solution was spin-coated onto the surface of the activation layer at a speed of 4000 rpm for 30 s to obtain the cathode buffer layer (thickness of 10 nm). A metal electrode with Ag as the material is deposited on the surface of the cathode buffer layer (the vacuum degree of the deposition is 1×10⁻⁶). -4 Pa), to obtain a metal electrode layer (100 nm thick), and obtain an upright organic solar cell (denoted as 20%).

[0047] Example 2 Referring to Example 1, the difference is that the concentration of coumarin in the activation layer solution is 2.8 mg / mL, resulting in an upright organic solar cell (denoted as 40%).

[0048] Example 3 Referring to Example 1, the difference is that the concentration of coumarin in the activation layer solution is 4.2 mg / mL, resulting in an upright organic solar cell (denoted as 60%).

[0049] Example 4 Referring to Example 1, the difference is that the concentration of coumarin in the activation layer solution is 5.6 mg / mL, resulting in an upright organic solar cell (denoted as 80%).

[0050] Example 5 Referring to Example 1, the difference is that the concentration of coumarin in the activation layer solution is 7 mg / mL, resulting in an upright organic solar cell (denoted as 100%).

[0051] Example 6 Referring to Example 1, the difference is that the concentration of coumarin in the activation layer solution is 8.4 mg / mL, resulting in an upright organic solar cell (denoted as 120%).

[0052] Comparative Example 1 Referring to Example 1, the difference is that the concentration of coumarin in the activation layer solution is 0, resulting in an upright organic solar cell (denoted as w / o).

[0053] Example 7 Referring to Example 1, the difference is that the electron acceptor in the activation layer solution is Y6, and the concentration of coumarin is 7 mg / mL, resulting in an upright organic solar cell.

[0054] Comparative Example 2 Referring to Example 7, the difference is that the concentration of coumarin in the activation layer solution is 0, resulting in an upright organic solar cell (denoted as w / o).

[0055] Example 8 Referring to Example 1, the difference is that the electron donor in the activation layer solution is D18, the concentration of the electron donor is 5 mg / mL, the concentration of the electron acceptor L8-BO is 6.0 mg / mL, and the concentration of coumarin is 5 mg / mL, thus obtaining an upright organic solar cell.

[0056] Comparative Example 3 Referring to Example 8, the difference is that the concentration of coumarin in the activation layer solution is 0, resulting in an upright organic solar cell (denoted as w / o).

[0057] Test case The organic solar cells with the upright structure described in Examples 1-8 and Comparative Example 1 were placed in a light intensity density of 100 mW / cm². 2 Under standard sunlight AM 1.5G, the test J - V The properties and external quantum efficiency (EQE) spectra were characterized to determine the effect of coumarin on the photovoltaic performance of organic solar cells; in, Figure 1 Organic solar cells with upright structures as described in Examples 1-6 and Comparative Example 1 J - V Characteristic curves (a), short-circuit current and open-circuit voltage as a function of coumarin addition (b), and filler factor and photoelectric conversion efficiency as a function of coumarin addition (c); Figure 1 It is known that the addition of coumarin can effectively improve the open-circuit voltage, short-circuit current, and fill factor of PM6:L8-BO-based organic solar cells, thereby improving the photoelectric conversion efficiency of the device. Moreover, with the increase of coumarin concentration, the open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency generally show a trend of first increasing and then decreasing. Table 1 shows the performance parameters of the organic solar cells with upright structures described in Examples 1-6 and Comparative Example 1; Table 1 Performance parameters of the upright organic solar cells described in Examples 1-6 and Comparative Example 1

[0058] Note: V oc Open circuit voltage, J sc Where is the short-circuit current density, FF is the fill factor, and PCE is the photoelectric conversion efficiency; Table 1 shows that the addition of coumarin can simultaneously optimize battery performance. V oc , J sc Combined with a stable FF, the photoelectric conversion efficiency is significantly improved; however, more is not always better (the performance of Example 6 is slightly reduced), and there is an optimal range of addition (around Example 5). Figure 2 Organic solar cells with upright structures as described in Example 7 and Comparative Example 2 JV Characteristic curves, from Figure 2 It can be seen that, combined J - V The overall trend of the curve, the battery corresponding to Example 7 with added coumarin, its J sc With a better filler factor FF, the final photoelectric conversion efficiency was higher than that of the control example 2 without coumarin. Table 2 shows the performance parameters of the upright organic solar cells described in Example 7 and Comparative Example 2; Table 2 Performance parameters of the upright organic solar cells described in Example 7 and Comparative Example 2

[0059] Note: V oc Open circuit voltage, J sc Where is the short-circuit current density, FF is the fill factor, and PCE is the photoelectric conversion efficiency; As shown in Table 2, the PCE of the organic solar cell with the upright structure described in Example 7 is significantly increased compared to that of the organic solar cell with the upright structure described in Comparative Example 2, increasing from 14.57% to 16.62%. Figure 3 Organic solar cells with upright structures as described in Example 8 and Comparative Example 3 JV Characteristic curves, from Figure 3 It can be seen that, combined J - V The overall trend of the curve, the battery corresponding to Example 8 with added coumarin, its J sc With a better filler factor FF, the final photoelectric conversion efficiency was higher than that of the comparative example 3 without added coumarin; Table 3 shows the performance parameters of the upright organic solar cells described in Example 8 and Comparative Example 3; Table 3 Performance parameters of the upright organic solar cells described in Example 8 and Comparative Example 3

[0060] Note: V oc Open circuit voltage, J sc Where is the short-circuit current density, FF is the fill factor, and PCE is the photoelectric conversion efficiency; As shown in Table 3, the PCE of the organic solar cell with the upright structure described in Example 8 is significantly increased compared to that of the organic solar cell with the upright structure described in Comparative Example 3, increasing from 15.62% to 16.94%.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An activation layer for a solar cell, characterized in that, Including electron donors, electron acceptors, and coumarin and their derivatives; The electron donor is a polymer electron donor; The electron acceptor is a non-fullerene electron acceptor.

2. The solar cell activation layer as described in claim 1, characterized in that, The mass ratio of the electron donor to the electron acceptor is 1:(1.1~1.4).

3. The solar cell activation layer as described in claim 1 or 2, characterized in that, The electron donor includes one or more of PM6, D18, PTQ10, PBDB-T, and D18-Cl.

4. The solar cell activation layer as described in claim 1 or 2, characterized in that, The electron acceptor includes one or more of L8-BO, Y6, BTP-eC9, AQX-2F, and N3-4F.

5. The solar cell activation layer as described in claim 1, characterized in that, The mass ratio of the electron donor to the coumarin and its derivatives is (4~8):(0.8~9.6).

6. The method for preparing the active layer of a solar cell according to any one of claims 1 to 5, characterized in that, Includes the following steps: An activation layer solution is obtained by mixing an electron donor, an electron acceptor, coumarin and its derivatives with an organic solvent. In a protective atmosphere, the activation layer solution is coated onto the substrate surface and then annealed to obtain the solar cell activation layer.

7. The preparation method according to claim 6, characterized in that, The concentration of electron donors in the activation layer solution is 4-8 mg / mL; The annealing temperature is 90~100℃ and the time is 5~10min.

8. The application of the solar cell activation layer according to any one of claims 1 to 5 or the solar cell activation layer prepared by the preparation method according to claim 6 or 7 in a solar cell.

9. A solar cell, characterized in that, Including the activation layer; The activation layer is the solar cell activation layer according to any one of claims 1 to 5 or the solar cell activation layer prepared by the preparation method according to claim 6 or 7.

10. The solar cell as claimed in claim 9, characterized in that, It also includes a conductive glass substrate, an anode buffer layer, a cathode buffer layer, and a metal electrode layer; The conductive glass substrate, anode buffer layer, activation layer, cathode buffer layer and metal electrode layer are stacked sequentially.

Images