Solar cell activation layer added with nitrophenol, preparation method and application of solar cell activation layer, and solar cell

Abstract

The invention relates to the technical field of solar cell activation layers, in particular to a solar cell activation layer added with nitrophenol, a preparation method and application of the solar cell activation layer and a solar cell. The invention provides a solar cell activation layer added with nitrophenol. The solar cell activation layer comprises an electron donor, an electron acceptor and nitrophenol, 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 added with the nitrophenol, the nitrophenol is selected as a solid additive, so that the problem of high toxicity can be solved, and meanwhile, the photoelectric conversion efficiency of the solar cell can be improved.

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 with added nitrophenol, its preparation method and application, and solar cells. Background Technology

[0002] Solar cells are a promising sustainable green energy technology, with inexhaustible resources. Organic solar cells (OSCs) have attracted much attention due to their low solution processing costs, flexibility, lightweight, and transparency. In recent years, with the rapid development of donor / acceptor materials and the optimization of device processes, the photoelectric conversion efficiency (PCE) of a single OSC has reached 21%.

[0003] As the core of OSCs, the activation layer, responsible for processes such as light absorption, exciton dissociation, and charge transport, directly determines the device efficiency and stability through its morphology and carrier transport performance. Current high-efficiency OSCs require complex post-processing to optimize the activation layer morphology, but this process suffers from poor repeatability and stability, severely limiting large-scale production. Solid additives are one of the simplest and most effective methods for optimizing device performance. They offer numerous advantages, including simple fabrication processes, the ability to improve the morphology of the activation layer and device stability by controlling film formation kinetics and adjusting interactions with other materials in the activation layer, making them one of the most effective strategies driving the rapid development of OSCs.

[0004] However, existing solid additives often contain halogens and are highly toxic, which does not align with industry development trends. Therefore, solid additives that are easy to prepare and can effectively improve the performance of the activation layer have become a research hotspot. Nitrophenol is a non-halogenated organic compound with a simple structure, is environmentally friendly, and has low toxicity. Furthermore, it can form various interactions with donor and acceptor materials in the activation layer, effectively improving the morphology of the activation layer and enhancing device performance. Currently, there are no reports on the application of nitrophenol as a solid additive in the activation layer of OSCs. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a solar cell activation layer with added nitrophenol, its preparation method and application, and a solar cell. The use of nitrophenol as a solid additive in the solar cell activation layer with added nitrophenol can solve the problem of high toxicity, while simultaneously improving the photoelectric conversion efficiency of the solar cell.

[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 with added nitrophenol, comprising an electron donor, an electron acceptor, and nitrophenol; 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 D18, PM6, PM7, D18-Cl, and PTQ10.

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

[0010] Preferably, the nitrophenol accounts for 5% to 30% of the mass percentage of the electron donor.

[0011] Preferably, the nitrophenol includes one or more of o-nitrophenol, p-nitrophenol, and m-nitrophenol.

[0012] The present invention also provides a method for preparing the activation layer of a solar cell with added nitrophenol as described in the above technical solution, comprising the following steps: An activation layer solution is obtained by mixing an electron donor, an electron acceptor, nitrophenol, and 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 with added nitrophenol.

[0013] Preferably, the concentration of the electron donor in the activation layer solution is 3.5~8 mg / mL; The annealing temperature is 90~100℃ and the time is 5~10 min.

[0014] The present invention also provides the application of the solar cell activation layer with added nitrophenol as described in the above technical solution or the solar cell activation layer with added nitrophenol prepared by the preparation method described in the above technical solution in solar cells.

[0015] The present invention also provides a solar cell, including an activation layer; The activation layer is the solar cell activation layer with added nitrophenol as described in the above technical solution or the solar cell activation layer with added nitrophenol prepared by the preparation method described in the above technical solution.

[0016] This invention provides a solar cell activation layer with added nitrophenol. The activation layer comprises an electron donor, an electron acceptor, and nitrophenol; the electron donor is a polymer electron donor; and the electron acceptor is a non-fullerene electron acceptor. This invention introduces nitrophenol as a solid additive into the solar cell activation layer, which has application value in improving the photoelectric conversion efficiency of organic solar cells. The main reason is that nitrophenol has a large π-π conjugated system and high polarity, which allows it to form various interactions with the polymer electron donor and / or non-fullerene electron acceptor in the activation layer, such as π-π interactions, hydrogen bonds, and non-covalent bonds. These multiple interactions not only broaden the absorption spectrum of the activation layer, enhancing the utilization rate of organic solar cells and increasing photocurrent, but also help form more high-speed channels for carrier transport, improving carrier mobility, reducing charge recombination, and increasing the fill factor. In addition, the introduction of nitrophenol can regulate the molecular aggregation in the activation layer, optimize the morphology of the activation layer, and help obtain better phase separation size and form a better three-dimensional interpenetrating network structure, thereby improving the photocurrent density and fill factor of the device, so as to improve the PCE of the device. Attached Figure Description

[0017] Figure 1 The organic solar cells with the upright structure described in Examples 1-5 (which correspond to 5%, 10%, 15%, 20%, and 30% respectively) and Comparative Example 1 are examples of such cells. J - V Characteristic curves (a), short-circuit current and open-circuit voltage as a function of o-nitrophenol addition (b), and fill factor and photoelectric conversion efficiency as a function of o-nitrophenol addition (c). Figure 2 Organic solar cells with upright structures as described in Examples 6-10 (Effects 6-10 correspond to 5%, 10%, 15%, 20%, and 30% respectively) and Comparative Example 1. J - V Characteristic curves (a), short-circuit current and open-circuit voltage as a function of o-nitrophenol addition (b), and fill factor and photoelectric conversion efficiency as a function of o-nitrophenol addition (c). Detailed Implementation

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

[0019] 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.

[0020] 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.

[0021] In this invention, the electron donor preferably includes one or more of D18, PM6, PM7, D18-Cl, and PTQ10. 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 an embodiment of this invention, the electron donor is specifically D18.

[0022] In this invention, the electron acceptor preferably includes one or more of L8-BO, Y6, Y6-BO-4F, BTP-eC9, and N3-4Cl. 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 an embodiment of this invention, the electron acceptor is specifically L8-BO.

[0023] In this invention, the nitrophenol includes one or more of o-nitrophenol, p-nitrophenol, and m-nitrophenol, more preferably o-nitrophenol or p-nitrophenol; when the nitrophenol is two or more of the above-mentioned specific selections, this invention does not have 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 nitrophenol can be o-nitrophenol or p-nitrophenol.

[0024] In this invention, the nitrophenol accounts for 5% to 30% of the mass percentage of the electron donor, more preferably 5%, 10%, 15%, 20%, 25% or 30%.

[0025] The present invention also provides a method for preparing the activation layer of a solar cell with added nitrophenol as described in the above technical solution, comprising the following steps: An activation layer solution is obtained by mixing an electron donor, an electron acceptor, nitrophenol, and 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 with added nitrophenol.

[0026] Preferably, the concentration of the electron donor in the activation layer solution is 3.5~8 mg / mL; The annealing temperature is 90~100℃ and the time is 5~10 min.

[0027] This invention involves mixing an electron donor, an electron acceptor, nitrophenol, and 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. In an embodiment of this invention, the organic solvent can be chloroform.

[0029] In this invention, the mixing process is preferably carried out by mixing the electron donor, electron acceptor, and organic solvent before adding nitrophenol. This invention does not impose any special limitations on the mixing process or the nitrophenol; any mixing process and addition method well known to those skilled in the art can be used.

[0030] In this invention, the concentration of the electron donor in the activation layer solution is preferably 3.5~8 mg / mL, more preferably 3.5 mg / mL, 4 mg / mL, 4.5 mg / mL, 5 mg / mL, 5.5 mg / mL, 6 mg / mL, 6.5 mg / mL, 7 mg / mL, 7.5 mg / mL, or 8 mg / mL. In an embodiment of this invention, the concentration of the electron donor in the activation layer solution is specifically 6 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 with added nitrophenol.

[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, the spin coating speed is preferably 4500 rpm, and the spin coating time is preferably 30 s.

[0034] In this invention, the coating amount is preferably 1.5 cm². 14–17 μL is coated onto a 1.5 cm substrate surface, more preferably onto a 1.5 cm² area. 14 μL, 15 μL, 16 μL, or 17 μL are coated onto a 1.5 cm substrate surface. In embodiments of the invention, the coating amount is specifically defined as covering an area of ​​1.5 cm². 15 μL was coated onto a 1.5 cm 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 5~10 min, more preferably 5 min, 6 min, 7 min, 8 min, 9 min or 10 min. In an embodiment of this invention, the annealing temperature can be 95℃ and the annealing time can be 5 min.

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

[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 with added nitrophenol as described in the above technical solution or the solar cell activation layer with added nitrophenol prepared by the preparation method described in the above technical solution.

[0039] In this invention, the solar cell preferably 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 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 limitation on the drying time; any time well-known to those skilled in the art can be used. This invention does not impose any special limitation on the conditions for the ultraviolet ozone plasma treatment; any conditions well-known 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 1.5% PEDOT:PSS aqueous solution is mixed with water at a 1:1 volume ratio, filtered through a 0.22 μm aqueous filter membrane, and then 20 μL of the PEDOT:PSS aqueous solution is spin-coated onto the surface of a conductive glass substrate at 3000 rpm for 30 s using a pipette. The substrate is then annealed in air at 155°C for 15 min 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 PDINN. In an embodiment of this invention, the preparation process of the cathode buffer layer is as follows: the PDINN is dissolved in methanol to obtain a PDINN solution with a concentration of 1 mg / mL; then, 35 μL of the PDINN solution is spin-coated onto the surface of the activation layer at a rotation speed of 3000 rpm for 30 s 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 the embodiments of this invention, the material of the metal electrode layer is specifically Ag, with a thickness of 100 nm; 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. -4Pa, 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 (1.5 cm²). After cleaning (1.5cm), the substrate was ultrasonically cleaned with deionized water, acetone and isopropanol for 15 min each, dried at 80℃ and treated with ultraviolet ozone plasma for 10 min to obtain the pretreated conductive glass substrate. A 1.5% PEDOT:PSS aqueous solution was filtered through a 0.22 μm aqueous filter membrane. Then, 30 μL of the PEDOT:PSS aqueous solution was spin-coated onto the pretreated conductive glass substrate at 3000 rpm for 30 s using a pipette. The substrate was then annealed in air at 155°C for 15 min to obtain the anode buffer layer (25 nm thick). After mixing electron donor D18, electron acceptor L8-BO, and chloroform, o-nitrophenol was added to obtain an activation layer solution (the concentration of D18 was 6 mg / mL, the concentration of L8-BO was 7.2 mg / mL, and the concentration of o-nitrophenol was 0.3 mg / mL). Then, under a nitrogen atmosphere, 15 μL of the activation layer solution was spin-coated at 4500 rpm for 30 s and annealed at 95 °C for 10 min to obtain an activation layer (thickness of 100 nm). PDINN was dissolved in methanol to obtain a PDINN solution with a concentration of 1 mg / mL. Then, 35 μL of the PDINN solution was pipetted onto the surface of the activation layer at a speed of 3000 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), thus obtaining an upright organic solar cell.

[0047] Example 2 Referring to Example 1, the difference is that the concentration of o-nitrophenol in the activation layer solution is 0.6 mg / mL, resulting in an upright organic solar cell.

[0048] Example 3 Referring to Example 1, the difference is that the concentration of o-nitrophenol in the activation layer solution is 0.9 mg / mL, resulting in an upright organic solar cell.

[0049] Example 4 Referring to Example 1, the difference is that the concentration of o-nitrophenol in the activation layer solution is 1.2 mg / mL, resulting in an upright organic solar cell.

[0050] Example 5 Referring to Example 1, the difference is that the concentration of o-nitrophenol in the activation layer solution is 1.8 mg / mL, resulting in an upright organic solar cell.

[0051] Example 6 Referring to Example 1, the difference is that o-nitrophenol in the activation layer solution is replaced with p-nitrophenol to obtain an upright organic solar cell.

[0052] Example 7 Referring to Example 2, the difference is that o-nitrophenol in the activation layer solution is replaced with p-nitrophenol to obtain an upright organic solar cell.

[0053] Example 8 Referring to Example 3, the difference is that o-nitrophenol in the activation layer solution is replaced with p-nitrophenol to obtain an upright organic solar cell.

[0054] Example 9 Referring to Example 4, the difference is that o-nitrophenol in the activation layer solution is replaced with p-nitrophenol to obtain an upright organic solar cell.

[0055] Example 10 Referring to Example 5, the difference is that o-nitrophenol in the activation layer solution is replaced with p-nitrophenol to obtain an upright organic solar cell.

[0056] Comparative Example 1 Referring to Example 1, the difference is that the concentration of o-nitrophenol 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 1-10 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 nitrophenol on the photovoltaic performance of organic solar cells; in, Figure 1 The organic solar cells with the upright structure described in Examples 1-5 (which correspond to 5%, 10%, 15%, 20%, and 30% respectively) and Comparative Example 1 are examples of such cells. J - V Characteristic curves (a), short-circuit current and open-circuit voltage as a function of o-nitrophenol addition (b), and fill factor and photoelectric conversion efficiency as a function of o-nitrophenol addition (c). Figure 2 Organic solar cells with upright structures as described in Examples 6-10 (Effects 6-10 correspond to 5%, 10%, 15%, 20%, and 30% respectively) and Comparative Example 1. J - V Characteristic curves (a), short-circuit current and open-circuit voltage as a function of o-nitrophenol addition (b), and fill factor and photoelectric conversion efficiency as a function of o-nitrophenol addition (c); Figures 1-2 It is known that the addition of nitrophenol can effectively improve the open-circuit voltage, short-circuit current, and fill factor of organic solar cells, thereby improving the photoelectric conversion efficiency of the device. Furthermore, with the increase of nitrophenol 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 1-10 and Comparative Example 1; Table 1 Performance parameters of the upright organic solar cells described in Examples 1-10 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; As shown in Table 1, the addition of nitrophenol can simultaneously optimize the battery performance. J sc And FF, combined with relatively stable V oc This ultimately significantly improves photoelectric conversion efficiency; however, more is not always better, as there is an optimal range for the amount added.

[0059] 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. A solar cell activation layer with added nitrophenol, characterized in that, Including electron donors, electron acceptors, and nitrophenol; The electron donor is a polymer electron donor; The electron acceptor is a non-fullerene electron acceptor.

2. The solar cell activation layer with added nitrophenol 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 with added nitrophenol as described in claim 1 or 2, characterized in that, The electron donor includes one or more of D18, PM6, PM7, D18-Cl, and PTQ10.

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

5. The solar cell activation layer with added nitrophenol as described in claim 1, characterized in that, The nitrophenol accounts for 5% to 30% of the mass percentage of the electron donor.

6. The solar cell activation layer with added nitrophenol as described in claim 1 or 5, characterized in that, The nitrophenol includes one or more of o-nitrophenol, p-nitrophenol, and m-nitrophenol.

7. The method for preparing the solar cell activation layer with added nitrophenol according to any one of claims 1 to 6, characterized in that, Includes the following steps: An activation layer solution is obtained by mixing an electron donor, an electron acceptor, nitrophenol, and 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 with added nitrophenol.

8. The preparation method according to claim 7, characterized in that, The concentration of electron donors in the activated layer solution is 3.5~8 mg / mL; The annealing temperature is 90~100℃ and the time is 5~10min.

9. The application of the solar cell activation layer with added nitrophenol as described in any one of claims 1 to 6, or the solar cell activation layer with added nitrophenol prepared by the preparation method described in claim 7 or 8, in a solar cell.

10. A solar cell, characterized in that, Including the activation layer; The activation layer is the solar cell activation layer with added nitrophenol as described in any one of claims 1 to 6, or the solar cell activation layer with added nitrophenol prepared by the preparation method described in claim 7 or 8.

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