Perovskite solar cell based on fluoropyridine additive with strong electron-withdrawing group substitution and preparation method thereof

Abstract

The application discloses a perovskite solar cell based on fluoropyridine additive with strong electron-withdrawing group substitution and a preparation method thereof, and the perovskite solar cell comprises a conductive electrode FTO, a first hole transport layer, a second hole transport layer, a perovskite active layer, a passivation layer, an electron transport layer, an interface modification layer and a metal electrode layer; wherein the perovskite active layer comprises a fluoropyridine additive with strong electron-withdrawing group substitution. 2+ The application introduces a strong electron-withdrawing group at a key position of the fluoropyridine, enhances the coordination effect with Pb 2+ ions in the perovskite, accurately passivates surface uncoordinated metal defects, and inhibits the formation of deep energy level trap states. In addition, the additive has a significant regulation effect on the perovskite film forming process, can promote the formation of large grains and dense film layers, improve the stability and repeatability of the device, and finally obtain a perovskite solar cell with high performance and high stability.

Description

Technical Field

[0001] This invention relates to the field of solar cells, and more specifically to a perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group and its preparation method. Background Technology

[0002] With the continuous advancement of science and technology, global energy consumption is steadily increasing. Limited fossil fuel sources necessitate research into sustainable and renewable energy sources. Converting sunlight into electricity is one of the most promising areas of research, potentially meeting the growing energy needs of future generations without the negative impacts of global climate change. Solar cell technology offers an environmentally friendly and renewable energy route, directly converting photon energy into electricity.

[0003] Perovskite solar cells, as third-generation solar cells, are widely promoted as an economically and environmentally viable renewable technology alternative to traditional solar cell technology due to their abundant raw materials, low production costs, and high efficiency, aiming to address global challenges in energy production and climate change. However, the stability of perovskite solar cells under harsh environments such as heat treatment, light, and humidity remains a bottleneck hindering their further commercialization. Many methods have been developed to rapidly improve the performance and stability of perovskite solar cells, among which additives are widely used in high-efficiency, stable, and hysteresis-free perovskite solar cells, playing a crucial role in various breakthroughs in perovskite solar cells. Depending on the specific additive composition and processing route, the use of additives can affect perovskite crystallization and thin film formation, bulk and surface / interface defect passivation, or interfacial tuning of structure and energy.

[0004] In conclusion, a new technical solution is urgently needed to address the problems existing in the current technology. Summary of the Invention

[0005] Based on this, the present invention provides a perovskite solar cell based on the effect of a fluorinated pyridine additive with strong electron-withdrawing groups. The present invention uses a specific additive as the perovskite active layer material. This additive introduces strong electron-withdrawing groups at key sites of the fluorinated pyridine structure, enhancing the synergistic effect with the perovskite material, precisely passivating uncoordinated metal defects on the surface, and suppressing the formation of deep-level trap states. This additive also helps to regulate the perovskite film formation process, improve the film structure, and enhance the stability and reproducibility of the device, ultimately resulting in a high-performance and highly stable perovskite solar cell. In summary, the present invention improves the overall performance of perovskite solar cells, achieving higher photoelectric conversion efficiency and demonstrating promising application prospects.

[0006] One object of the present invention is to provide a perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group, wherein the perovskite solar cell based on the effect of the fluorinated pyridine additive with a strong electron-withdrawing group comprises, from bottom to top:

[0007] The structure consists of a conductive electrode FTO, a first hole transport layer, a second hole transport layer, a perovskite active layer, a passivation layer, an electron transport layer, an interface modification layer, and a metal electrode layer.

[0008] The perovskite active layer includes fluoropyridine additives substituted with strong electron-withdrawing groups.

[0009] Furthermore, in the fluoropyridine additive substituted with a strong electron-withdrawing group, the strong electron-withdrawing group is selected from one or more of nitro, cyano, carbonyl, carboxyl, trifluoromethyl, and sulfonic acid groups.

[0010] Furthermore, the fluoropyridine additive substituted with a strong electron-withdrawing group is selected from one or more of the following structures.

[0011]

[0012] Preferably, the fluoropyridine additive substituted with the strong electron-withdrawing group is 4-cyano-3,5-difluoropyridine.

[0013] Furthermore, the material of the first hole transport layer is NiO. x The material of the second hole transport layer is SAM material.

[0014] Furthermore, the passivating agent of the passivation layer includes 3-methylthiopropyl-1-aminehydroiodide (3MTPAI) and diammonium succinate (BDADI).

[0015] Furthermore, the material of the electron transport layer is PCBM.

[0016] Furthermore, the material of the interface modification layer is BCP.

[0017] Another object of the present invention is to provide a method for preparing the perovskite solar cell based on the effect of the fluorinated pyridine additive with a strong electron-withdrawing group, wherein the method for preparing the perovskite solar cell based on the effect of the fluorinated pyridine additive with a strong electron-withdrawing group includes the following steps:

[0018] S1. Clean the conductive electrode FTO to obtain the conductive electrode FTO;

[0019] S2. Dissolve the hole transport layer material in the first solvent to form a first hole transport layer solution and a second hole transport layer solution; spin-coat the first hole transport layer solution onto the conductive electrode FTO, anneal to form a first hole transport layer; spin-coat the second hole transport layer solution onto the first hole transport layer, anneal to form a second hole transport layer.

[0020] S3. Dissolve the perovskite precursor material in a second solvent to form a perovskite precursor solution; add a fluoropyridine additive with a strong electron-withdrawing group to the perovskite precursor solution, then spin-coat it onto the second hole transport layer, add an antisolvent, and anneal to form a perovskite active layer.

[0021] S4. Dissolve the passivating agent in a third solvent to form a passivation layer solution; spin-coat the passivation layer solution onto the perovskite active layer and anneal to form a passivation layer;

[0022] S5. Dissolve the electron transport layer material in a fourth solvent to form an electron transport layer solution; spin-coat the electron transport layer solution onto the passivation layer and anneal it to form an electron transport layer.

[0023] S6. Dissolve the interface modification layer material in the fifth solvent to form an interface modification layer solution; spin-coat the interface modification layer solution onto the electron transport layer to form an interface modification layer;

[0024] S7. A metal electrode is deposited on the surface of the interface modification layer to form a metal electrode layer, thereby obtaining a perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups.

[0025] Further, in step S3, the second solvent is a mixed solution of DMF and DMSO with a volume ratio of (5-15):1; preferably, the volume ratio is 10:1.

[0026] Further, in step S3, the antisolvent is selected from chlorobenzene solvents, toluene solvents, or ester solvents, or derivatives of the above solvents.

[0027] Further, in step S3, the perovskite precursor material includes a monovalent cationic halide, a divalent metal cationic halide, and methylamine chloride (MACl);

[0028] The monovalent cation halide is selected from one or more of formamidine iodide (FAI), methylammonium iodide, or cesium iodide; the divalent metal cation halide is selected from one or more of lead iodide or lead bromide.

[0029] Furthermore, the molar ratio of the monovalent cationic halide, the divalent metal cationic halide, methylamine chloride, and the fluoropyridine additive substituted with a strong electron-withdrawing group is (0.5-1.5):1:(0.1-0.5):(0.25-2).

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] The perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups provided by this invention introduces strong electron-withdrawing groups at key sites in the structure of the fluorinated pyridine additive, thereby enhancing the interaction with Pb in the perovskite. 2+ The coordination of ions precisely passivates uncoordinated metal defects on the surface, suppressing the formation of deep-level trap states. Furthermore, this additive significantly regulates the perovskite film formation process, promoting the formation of large-grained, dense films, improving device stability and repeatability, and ultimately resulting in high-performance and highly stable perovskite solar cells. The perovskite solar cells treated with the additive provided by this invention exhibit significantly higher PCE than those obtained without the additive. Attached Figure Description

[0032] Figure 1 A structural diagram of the perovskite solar cell based on a fluorinated pyridine additive with a strong electron-withdrawing group substituted according to the present invention is shown.

[0033] Figure 2 The XRD patterns of the perovskite active layers prepared in Examples 1-6 and the comparative examples are shown.

[0034] Figure 3 The JV diagrams of the perovskite solar cells prepared in Example 3 and the comparative example are shown. Detailed Implementation

[0035] To more clearly illustrate the technical solution of the present invention, the following embodiments are provided. Unless otherwise stated, the raw materials, reactions, and post-processing methods appearing in the embodiments are all commercially available raw materials and technical methods well known to those skilled in the art.

[0036] The terms "preferred," "more preferably," and "more suitable" used in this invention refer to embodiments of the invention that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this invention.

[0037] It should be understood that, except in any operational instance or otherwise indicated, the amounts or all figures representing ingredients used, for example, in the specification and claims, should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​varying according to the desired performance to be obtained according to the invention.

[0038] Abbreviations used in the embodiments of this invention:

[0039] Me-4pacz is (4-(3,6-dimethyl-9H-carbazole-9-yl)butylphosphonic acid);

[0040] PCBM is [6,6]-phenyl-C61-butyrate methyl ester;

[0041] IPA stands for isopropanol;

[0042] CB stands for chlorobenzene;

[0043] BCP stands for dicyandiamide benzene.

[0044] Example 1

[0045] A perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group, wherein the perovskite solar cell based on the effect of the fluorinated pyridine additive with a strong electron-withdrawing group comprises, from bottom to top:

[0046] The structure consists of a conductive electrode FTO (500 nm), a first hole transport layer (30 nm), a second hole transport layer (1 nm), a perovskite active layer (480 nm), a passivation layer (5 nm), an electron transport layer (30 nm), an interface modification layer (5 nm), and a metal electrode layer (90 nm).

[0047] The method for preparing the perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups includes the following steps:

[0048] S1. The FTO conductive glass is cleaned with washing solution, deionized water, acetone and alcohol respectively, and then surface treated with a plasma cleaner to obtain the conductive electrode FTO.

[0049] S2, Add 10mg of NiO xDissolve Me-4pacz in deionized water and sonicate for 3 min to obtain a first hole transport layer solution with a concentration of 10 mg / ml; dissolve Me-4pacz in anhydrous ethanol and stir at room temperature for 3 h to obtain a second hole transport layer solution with a concentration of 3 mmol / ml; spin-coat the first hole transport layer solution onto the conductive electrode FTO at 1500 rpm for 30 s and anneal at 150°C in ambient air for 10 min to form the first hole transport layer; spin-coat the second hole transport layer solution onto the first hole transport layer at 4000 rpm for 30 s and anneal at 100°C for 10 min to form the second hole transport layer;

[0050] S3. Dissolve 189.2 mg of FAI, 532.5 mg of PbI2, and 11.1 mg of MACl (15 mol% of PbI2) in a mixed solution of DMF and DMSO (DMF:DMSO = 10:1, v / v) to obtain a 1.1 M FAPbI3 perovskite precursor solution. Stir at room temperature for 10 h. Finally, dissolve the additive 4-cyano-3,5-difluoropyridine (25 mol% of PbI2) in the perovskite precursor solution and stir at room temperature for 1 h. Spin-coat the second hole transport layer at 5000 rpm for 30 s, add the antisolvent CB dropwise, and anneal at 110 °C for 20 min to form the perovskite active layer.

[0051] S4. Dissolve 2.8 mg of 3MTPAI and 2.1 mg of BDADI in 1 ml of a mixed solution of IPA and CB (IPA:CB = 1:1, v / v), stir at room temperature for 8 h to form a passivation layer solution; spin-coat the passivation layer solution onto the perovskite active layer at 4000 rpm for 25 s, and anneal at 100 °C for 5 min to form a passivation layer;

[0052] S5. Dissolve 20 mg of electron transport layer material PCBM in 1 ml of CB, stir at 70°C for 8 h to form an electron transport layer solution; spin-coat the electron transport layer solution onto the passivation layer at 2000 rpm for 30 s, and anneal at 70°C for 10 min to form an electron transport layer.

[0053] S6. Dissolve 2 mg of BCP in 1 ml of IPA and stir at 70°C for 8 h to form an interface modification layer solution; spin-coat the interface modification layer solution onto the electron transport layer at 2000 rpm for 30 s to form an interface modification layer.

[0054] S7. Place the perovskite solar cell device prepared in the above steps in a vapor deposition equipment with the interface modification layer to be vaporized facing down. Place the metal Ag in an evaporation boat for heating and evaporation. Continuously adjust the evaporation rate during the vapor deposition process and observe the melting of the metal material in the evaporation boat. Finally, use the vapor deposition equipment to deposit a 90nm Ag electrode to form a metal electrode layer, thus obtaining a perovskite solar cell based on the action of a fluorinated pyridine additive with a strong electron-withdrawing group substitution.

[0055] Figure 1 A structural diagram of the perovskite solar cell based on a fluorinated pyridine additive with a strong electron-withdrawing group substituted according to the present invention is shown.

[0056] Example 2

[0057] A perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups is described in this embodiment. The difference between this embodiment and Example 1 is that in step S3, the amount of 4-cyano-3,5-difluoropyridine is modified to 50 mol% of PbI2. The other steps and amounts are the same as in Example 1.

[0058] Example 3

[0059] A perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups is described in this embodiment. The difference between this embodiment and Example 1 is that in step S3, the amount of 4-cyano-3,5-difluoropyridine is modified to 75 mol% of PbI2. The other steps and amounts are the same as in Example 1.

[0060] Example 4

[0061] A perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups is described in this embodiment. The difference between this embodiment and Example 1 is that in step S3, the amount of 4-cyano-3,5-difluoropyridine is modified to 100 mol% of PbI2. The other steps and amounts are the same as in Example 1.

[0062] Example 5

[0063] A perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups is described in this embodiment. The difference between this embodiment and Example 1 is that in step S3, 4-cyano-3,5-difluoropyridine is replaced with 4-carbonyl-3,5-difluoropyridine. The other steps and dosages are the same as in Example 1.

[0064] Example 6

[0065] A perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups is described in this embodiment. The difference between this embodiment and Example 1 is that in step S3, 4-cyano-3,5-difluoropyridine is replaced with 4-trifluoromethyl-3,5-difluoropyridine. The other steps and dosages are the same as in Example 1.

[0066] Comparative Example 1

[0067] A perovskite solar cell, the difference between this comparative example and Example 1 is that 4-cyano-3,5-difluoropyridine is not added in step S3, while the other steps and amounts are the same as in Example 1.

[0068] Test case

[0069] The photoelectric performance of perovskite solar cells based on fluorinated pyridine additives with strong electron-withdrawing groups prepared in the examples and comparative examples was tested.

[0070] Test method:

[0071] X-ray diffraction (XRD) patterns were collected on a Rigaku Ultima-IV instrument using a Cu-Kα radiation source at 2θ = 5–35°. JV characteristics were measured using a Keithley 2400 source unit at 100 mW cm⁻¹. -2 Measurements were taken under AM 1.5G sunlight using an Oriel 91192 solar simulator. Light intensity was measured using a Hamamatsu S1133 monocrystalline silicon reference cell (equipped with a KG-5 visible light filter), calibrated by the National Renewable Energy Laboratory (NREL).

[0072] The test results are shown in Table 1.

[0073] Table 1. Photoelectric performance test results of perovskite solar cells

[0074] Sample VOC (V) JSC(mA / cm 2 )]]> FF (%) PCE (%) Example 1 1.17 25.09 83.61 24.57 Example 2 1.17 25.91 84.59 25.68 Example 3 1.17 26.29 85.21 26.27 Example 4 1.17 25.67 84.72 25.48 Example 5 1.17 24.29 85.36 24.36 Example 6 1.17 24.53 84.49 24.17 Comparative Example 1 1.17 24.59 84.04 24.13

[0075] Figure 2 XRD patterns of the perovskite active layers prepared in Examples 1-6 and Comparative Example 1 are shown. Figure 2 As can be seen, compared with Comparative Example 1, Examples 1-4 generally exhibit higher peak intensities and narrower full width at half maximum (FWHM), reflecting superior crystallinity. Due to the different additives used, the peak intensities of Examples 5-6 are slightly weaker than those of Examples 1-4.

[0076] Figure 3 The JV diagrams of the perovskite solar cells prepared in Example 3 and Comparative Example 1 of the present invention are shown. Figure 3It can be seen that the short-circuit current density (Jsc) and fill factor (FF) of the device prepared in Example 3 are better than those of Comparative Example 1, showing higher photoelectric conversion efficiency (PCE).

[0077] Based on the test results above, as can be seen from the test results of Comparative Example 1 and Example 3, the perovskite battery using the 4-cyano-3,5-difluoropyridine additive has an absolute efficiency improvement of 2.14% compared to the unused battery.

[0078] The test results of Example 3 and Comparative Example 1 show that the introduction of a strong electron-withdrawing group at the key site (position 4) of 3,5-difluoropyridine significantly enhances the interaction between the cyano (-CN) structure in the additive material and Pb in the perovskite. 2+ The coordination of ions precisely passivates uncoordinated metal defects on the surface and suppresses the formation of deep-level trap states. Furthermore, this additive significantly regulates the perovskite film formation process, promoting the formation of large-grained, dense films and improving device stability and repeatability.

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0080] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group, characterized in that, The perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups includes, from bottom to top: The structure consists of a conductive electrode FTO, a first hole transport layer, a second hole transport layer, a perovskite active layer, a passivation layer, an electron transport layer, an interface modification layer, and a metal electrode layer. The perovskite active layer includes fluoropyridine additives substituted with strong electron-withdrawing groups. The fluoropyridine additive substituted with a strong electron-withdrawing group is selected from one or more of the following structures. 。 2. The perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups according to claim 1, characterized in that, The material of the first hole transport layer is NiO. x The material of the second hole transport layer is SAM material.

3. The perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups according to claim 1, characterized in that, The passivating agents of the passivation layer include 3-methylthiopropyl-1-amine hydrogen iodide and diammonium iodide.

4. The perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups according to claim 1, characterized in that, The electron transport layer is made of PCBM.

5. The perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group as described in claim 1, characterized in that, The material of the interface modification layer is BCP.

6. The method for preparing a perovskite solar cell based on the action of a fluoropyridine additive with a strong electron-withdrawing group as described in any one of claims 1-5, characterized in that, The method for preparing the perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups includes the following steps: S1. Clean the conductive electrode FTO to obtain the conductive electrode FTO; S2. Dissolve the hole transport layer material in the first solvent to form a first hole transport layer solution and a second hole transport layer solution; A first hole transport layer solution is spin-coated onto the conductive electrode FTO, and then annealed to form a first hole transport layer; a second hole transport layer solution is spin-coated onto the first hole transport layer, and then annealed to form a second hole transport layer. S3. Dissolve the perovskite precursor material in a second solvent to form a perovskite precursor solution; add a fluoropyridine additive with a strong electron-withdrawing group to the perovskite precursor solution, then spin-coat it onto the second hole transport layer, add an antisolvent, and anneal to form a perovskite active layer. S4. Dissolve the passivating agent in the third solvent to form a passivation layer solution; The passivation layer solution is spin-coated onto the perovskite active layer and annealed to form a passivation layer; S5. Dissolve the electron transport layer material in the fourth solvent to form an electron transport layer solution; The electron transport layer solution is spin-coated onto the passivation layer and then annealed to form an electron transport layer. S6. Dissolve the interface modification layer material in the fifth solvent to form an interface modification layer solution; The interface modification layer solution is spin-coated onto the electron transport layer to form an interface modification layer; S7. A metal electrode is deposited on the surface of the interface modification layer to form a metal electrode layer, thereby obtaining a perovskite solar cell based on the effect of fluorinated pyridine additives with strong electron-withdrawing groups.

7. The method for preparing a perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group according to claim 6, characterized in that, In step S3, the perovskite precursor material includes a monovalent cationic halide, a divalent metal cationic halide, and methylamine chloride; The monovalent cation halide is selected from one or more of formamidine iodide, methylammonium iodide, or cesium iodide; the divalent metal cation halide is selected from one or more of lead iodide or lead bromide.

8. The method for preparing a perovskite solar cell based on the effect of a fluorinated pyridine additive with a strong electron-withdrawing group according to claim 7, characterized in that, The molar ratio of the monovalent cationic halide, the divalent metal cationic halide, methyl chloride and the fluoropyridine additive substituted with a strong electron-withdrawing group is (0.5-1.5):1:(0.1-0.5):(0.25-2).

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