A perovskite solar cell with an organic polymer molecule modified perovskite layer

Abstract

This invention discloses a perovskite solar cell with an organic polymer molecule-modified perovskite layer, belonging to the field of photovoltaic solar energy material technology. The device structure, from bottom to top, includes a conductive glass layer, a hole transport layer, a perovskite layer, a perovskite modification layer, an electron transport layer, and a metal electrode layer; the perovskite layer has the structural formula FA. x MA y PbI3, where x is 0.7–0.9 and y is 0.1–0.3, and the perovskite modification layer includes linear polyethyleneimine. The linear polyethyleneimine has the molecular structure shown in formula (1). The hydroxyl groups in the linear polyethyleneimine can act as Lewis bases to interact with uncoordinated Pb at the perovskite grain boundaries and surface. 2+ Interactions can occur, effectively passivating lead ion defects; secondary amine groups can interact with unsaturated I... ‑ Hydrogen bonds are formed, which inhibits ion migration. At the same time, linear polyethyleneimine protects the perovskite layer from the influence of water molecules through hydrophobic long alkyl chains, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic solar energy materials technology, and more specifically, to a perovskite solar cell with an organic polymer molecule-modified perovskite layer and its preparation method. Background Technology

[0002] Since the beginning of the 21st century, human demand for and dependence on energy has increased dramatically. Non-renewable traditional fossil fuels are being rapidly depleted, and burning fossil fuels also causes environmental pollution problems such as the greenhouse effect and acid rain. Therefore, developing and utilizing renewable energy sources such as hydropower, wind power, and solar energy to replace traditional fossil fuels is crucial. Among these, solar energy resources are abundant, inexpensive, inexhaustible, and have broad application prospects. Solar cells are devices that convert solar energy into electrical energy and are currently the most efficient way to utilize solar energy. Currently, the power conversion efficiency of perovskite solar cells has increased significantly from 3.87% to 26.1%, and they also possess advantages such as excellent device performance, low manufacturing cost, and solution-processable fabrication, demonstrating enormous commercial potential.

[0003] However, since perovskite layers are mostly polycrystalline perovskite films prepared by solution methods, a large number of defects usually exist in the perovskite body, at the interface, and at the grain boundaries. Among them, uncoordinated Pb exists at the grain boundaries and the surface. 2+ The presence of defects can lead to nonradiative recombination of charge carriers, affecting device performance. Furthermore, perovskite is an ionic semiconductor material, exhibiting poor humidity stability and decomposing upon contact with water. Currently, perovskite solar cells still face numerous challenges, hindering their widespread adoption and application. Therefore, developing a perovskite layer modifier to improve the photoelectric conversion efficiency and stability of perovskite solar cells is of great significance.

[0004] CN 117979781 A discloses an inverted perovskite solar cell. The hole transport layer is formed using functionalized nickel oxide nanoparticles, which are prepared by surface hydroxylation treatment followed by grafting with self-assembled materials. The perovskite layer is prepared from a mixed solution of PbI2, FAI, MABr, MACl, CsI, and PbBr2. While existing technologies effectively improve the photoelectric efficiency of inverted perovskite solar cells, this invention does not address the stability of perovskite solar cells. Summary of the Invention

[0005] The primary objective of this invention is to overcome the shortcomings of the prior art and provide a perovskite solar cell.

[0006] Another object of the present invention is to provide a method for preparing a perovskite solar cell.

[0007] Another object of the present invention is to provide an application of perovskite solar cells in photovoltaic power plants, portable devices, military equipment, building-integrated photovoltaics, and indoor photovoltaics.

[0008] To achieve the above-mentioned technical objectives, the present invention is implemented through the following technical solution:

[0009] A perovskite solar cell with an organic polymer-modified perovskite layer has a device structure comprising, from bottom to top, a conductive glass layer, a hole transport layer, a perovskite layer, a perovskite modification layer, an electron transport layer, and a metal electrode layer; the perovskite layer has the structural formula FA. x MA y PbI3, where x is 0.7–0.9 and y is 0.1–0.3, and the perovskite modification layer includes linear polyethyleneimine.

[0010] This invention uses linear polyethyleneimine as a modifier to act on the perovskite layer. The hydroxyl groups in linear polyethyleneimine can act as Lewis bases to interact with uncoordinated Pb at the perovskite grain boundaries and surface. 2+ Interacting with each other, effectively passivating lead ion defects, the secondary amine group can react with unsaturated I... - By forming hydrogen bonds, linear polyethyleneimine is retained between grain boundaries through bonding with the perovskite, strengthening the linkages and forming an interpenetrating network, further suppressing ion migration within the perovskite. Furthermore, linear polyethyleneimine forms a hydrophobic and stable modification layer on the perovskite layer surface through its hydrophobic long alkyl chains, protecting the perovskite layer from the influence of water molecules, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0011] The linear polyethyleneimine modifier of this invention is used to improve the photoelectric conversion efficiency and stability of perovskite solar cells.

[0012] Specifically, the linear polyethyleneimine has an average molecular weight of 20,000 to 30,000.

[0013] Specifically, the perovskite modification layer is formed by first spin-coating the linear polyethyleneimine modifier onto the perovskite layer and then removing the solvent.

[0014] Specifically, the concentration of the linear polyethyleneimine modifier is 0.1–0.4 mg / mL.

[0015] Specifically, the spin-coating volume of the linear polyethyleneimine modifier is 30–50 μL.

[0016] Specifically, the spin-coating rate of the perovskite modified layer is 4000-6000 rpm.

[0017] Specifically, the spin-coating time of the perovskite modified layer is 25–35 s.

[0018] Specifically, the preparation method of the linear polyethyleneimine modifier includes the following steps:

[0019] The linear polyethyleneimine is added to a solvent and stirred to obtain the linear polyethyleneimine modifier.

[0020] Specifically, the solvent for the linear polyethyleneimine modifier is at least one of isopropanol, propanol, and ethanol.

[0021] Specifically, the hole transport layer is made of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], PEDOT:PSS, or NiO. x At least one of [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphoric acid (Me-2PACz) and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid (Me-4PACz).

[0022] More specifically, the hole transport layer is NiO. x And [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphoric acid (Me-2PACz).

[0023] Specifically, the electron transport layer is a carbon-60 derivative.

[0024] More specifically, the material of the electron transport layer is at least one of [6,6]-phenyl-C61-butyrate methyl ester, [6,6]-thienyl-C61-butyrate methyl ester, [6,6]-phenyl-C61-butyrate n-octyl ester or [6,6]-phenyl-C61-butyrate dodecyl ester.

[0025] Specifically, the material of the conductive glass layer is one or both of ITO conductive glass and FTO conductive glass.

[0026] Specifically, the material of the metal electrode layer is at least one of silver, gold, or copper.

[0027] The above-mentioned method for preparing perovskite solar cells includes the following steps:

[0028] S1: Prepare a hole transport layer on a conductive glass layer;

[0029] S2: Fabrication of a perovskite layer on the hole transport layer;

[0030] S3: Prepare a perovskite modification layer on the perovskite layer;

[0031] S4: An electron transport layer is prepared on the perovskite modified layer;

[0032] S5: Prepare a metal electrode layer on the electron transport layer to obtain a perovskite solar cell.

[0033] Specifically, the preparation method further includes step S0: cleaning the conductive glass layer.

[0034] More specifically, step S0 involves: ultrasonically cleaning the conductive glass alternately with ITO detergent, deionized water, acetone, and isopropanol, and then drying it to obtain a conductive glass layer.

[0035] Specifically, step S1 involves: subjecting the conductive glass layer to ultraviolet ozone treatment, and then spin-coating a hole transport layer solution prepared from the material of the hole transport layer onto the surface of the conductive glass to obtain the hole transport layer.

[0036] More specifically, in step S1, the spin coating rate is 3000-5000 rpm and the spin coating time is 25-35 s.

[0037] Specifically, step S2 involves spin-coating a perovskite solution prepared from the material of the perovskite layer onto the surface of the hole transport layer to obtain the perovskite layer.

[0038] More specifically, the perovskite material is formamidinium hydroiodate (FAI), methylammonium iodide (MAI), and lead iodide (PbI2).

[0039] More specifically, the solvent of the perovskite solution is at least one of DMF, DMSO, THF, acetone, isopropanol, toluene, or chlorobenzene.

[0040] More specifically, in step S2, the spin coating rate is 1000–5000 rpm, and the spin coating time is 5–35 s.

[0041] Specifically, step S3 involves spin-coating a linear polyethyleneimine modifier onto the perovskite layer and heating it to form a film, thereby obtaining the perovskite modified layer.

[0042] Specifically, step S4 involves: preparing an electron transport layer solution by spin-coating the electron transport layer material onto the surface of the perovskite modified layer, followed by spin-coating with copper bath (BCP) to obtain the electron transport layer.

[0043] More specifically, in step S4, the spin coating rate is 3000-5000 rpm and the spin coating time is 25-35 s.

[0044] Specifically, step S5 involves placing the electron transport layer prepared in S5 into a vacuum coating machine and evaporating a metal electrode layer to obtain a perovskite solar cell.

[0045] The present invention also protects the application of the perovskite solar cell in photovoltaic power plants, portable devices, military equipment, building-integrated photovoltaics, and indoor photovoltaics.

[0046] Compared with the prior art, the beneficial effects of the present invention are:

[0047] This invention uses linear polyethyleneimine as a modifier to act on the perovskite layer. The hydroxyl groups in linear polyethyleneimine can act as Lewis bases to interact with uncoordinated Pb at the perovskite grain boundaries and surface. 2+ Interacting with each other, effectively passivating lead ion defects, the secondary amine group can react with unsaturated I... - Hydrogen bonds are formed, which inhibits ion migration. At the same time, linear polyethyleneimine protects the perovskite layer from the influence of water molecules through hydrophobic long alkyl chains, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0048] The photoelectric conversion efficiency of the perovskite solar cell provided by this invention has been increased from 19.31% to 20.68%–22.87%, and after being placed at room temperature for 2304 hours (96 days), the photoelectric conversion efficiency still remains at 75%. Attached Figure Description

[0049] Figure 1 The JV curves are for the perovskite solar cells of Example 1 and Comparative Example 1.

[0050] Figure 2 The normalized efficiency-time curves are for the perovskite solar cells of Example 1 and Comparative Example 1.

[0051] Figure 3 The images show the steady-state photoluminescence spectra of the modified perovskite layer in Example 1 and the unmodified perovskite layer in Comparative Example 1.

[0052] Figure 4 The transient photoluminescence spectra of the perovskite layer with the modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1 are shown.

[0053] Figure 5 Figures a and b show the contact angles of the modified perovskite layer in Example 1 and the unmodified perovskite layer in Comparative Example 1, respectively.

[0054] Figure 6 The images show the XRD patterns of the perovskite films of Example 1 and Comparative Example 1 as they are placed in air over time. Detailed Implementation

[0055] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0056] The linear polyethyleneimine used in Examples 1-6 and Comparative Example 2 has the molecular structure shown in Formula (1):

[0057]

[0058] Mw is 25000.

[0059] Example 1

[0060] This embodiment provides a perovskite solar cell, which, from bottom to top, comprises a conductive glass layer, a hole transport layer, a perovskite layer, a perovskite modification layer, an electron transport layer, and a metal electrode layer; the perovskite layer has the structural formula FA. 0.8 MA 0.2 PbI3, the perovskite modification layer includes linear polyethyleneimine.

[0061] The perovskite modification layer is formed by first coating a perovskite layer with a perovskite layer modifier and then removing the solvent.

[0062] The concentration of the linear polyethyleneimine modifier was 0.25 mg / mL.

[0063] The preparation method of the above-mentioned linear polyethyleneimine modifier includes the following steps:

[0064] Add 0.25 mg of linear polyethyleneimine to 1 mL of isopropanol and stir magnetically at 65 °C for 10 min to obtain the linear polyethyleneimine modifier.

[0065] The above-mentioned method for preparing perovskite solar cells includes the following steps:

[0066] S0: The ITO conductive glass was ultrasonically cleaned for 15 minutes with ITO detergent, deionized water, acetone and isopropanol alternately, and then dried with argon gas to obtain a conductive glass layer.

[0067] S1: The conductive glass layer of S1 is placed in an ultraviolet ozone cleaner for ultraviolet ozone treatment. After treatment, 40 μL of 15 mg / mL NiO is spin-coated onto the surface of the conductive glass layer in air. xThe solution was spin-coated at 4000 rpm for 30 seconds, followed by annealing on a heated platform for 30 minutes. It was then transferred to a glove box under a nitrogen atmosphere and heated in NiO. x 40 μL of 0.4 mg / mL Me-2PACz solution was spin-coated onto the surface at a speed of 4000 rpm for 30 s. After spin-coating, the surface was transferred to a heating stage for heating to obtain a hole transport layer.

[0068] S2.1: Mix PbI2, FAI and MAI in a molar ratio of 5:4:1, dissolve in 1 mL DMF-DMSO, stir the mixture for 3 h to prepare a perovskite solution, wherein: V(DMF):V(DMSO)=4:1;

[0069] S2.2 First, spin-coat 65 μL of perovskite solution onto the surface of the hole transport layer at a speed of 1000 rpm for 5 s, then spin-coat at a speed of 5000 rpm for 35 s, then add chlorobenzene, and then transfer to a heating stage for heating to obtain the perovskite layer.

[0070] S3: Spin-coat 40 μL of perovskite layer modifier onto the perovskite layer at a spin speed of 5000 rpm for 30 s. Then transfer it to a heating stage to heat and form a film, thus obtaining the perovskite modified layer.

[0071] S4: 23 mg of electron transport layer material [6,6]-phenylC61 butyrate methyl ester (PC) 61 BM was dissolved in 1 mL of chlorobenzene to prepare PC. 61 BM electron transport layer solution, and take 35 μL PC 61 The BM electron transport layer solution was spin-coated onto the surface of the perovskite modified layer at a speed of 3000 rpm for 30 s. After spin-coating, the layer was transferred to a heating stage for heating. Then, 45 μL of 2.5 mg / mL copper bath solution (BCP) was spin-coated at a speed of 5000 rpm for 30 s to obtain the electron transport layer.

[0072] S5: Place the prepared electron transport layer into a vacuum coating machine, evacuate the vacuum, place the silver metal source into a tungsten boat, and deposit the silver metal electrode to obtain a perovskite solar cell.

[0073] Example 2

[0074] This embodiment provides a perovskite solar cell, the structure and preparation method of which differ from those in Example 1 in that the concentration of the linear polyethyleneimine modifier is 0.1 mg / mL.

[0075] The preparation method of the above-mentioned linear polyethyleneimine modifier includes the following steps:

[0076] Add 0.1 mg of linear polyethyleneimine to 1 mL of isopropanol and stir magnetically at 65 °C for 10 min to obtain the linear polyethyleneimine modifier.

[0077] The perovskite modification layer is formed by first coating a perovskite layer with a perovskite layer modifier and then removing the solvent.

[0078] The rest is the same as in Example 1.

[0079] Example 3

[0080] This embodiment provides a perovskite solar cell, the structure and preparation method of which differ from those in Example 1 in that the concentration of the linear polyethyleneimine modifier is 0.15 mg / mL.

[0081] The preparation method of the above-mentioned linear polyethyleneimine modifier includes the following steps:

[0082] Add 0.15 mg of linear polyethyleneimine to 1 mL of isopropanol and stir magnetically at 65 °C for 10 min to obtain the linear polyethyleneimine modifier.

[0083] The perovskite modification layer is formed by first coating a perovskite layer with a perovskite layer modifier and then removing the solvent.

[0084] The rest is the same as in Example 1.

[0085] Example 4

[0086] This embodiment provides a perovskite solar cell, the structure and preparation method of which differ from those in Example 1 in that the concentration of the linear polyethyleneimine modifier is 0.2 mg / mL.

[0087] The preparation method of the above-mentioned linear polyethyleneimine modifier includes the following steps:

[0088] Add 0.2 mg of linear polyethyleneimine to 1 mL of isopropanol and stir magnetically at 65 °C for 10 min to obtain the linear polyethyleneimine modifier.

[0089] The perovskite modification layer is formed by first coating a perovskite layer with a perovskite layer modifier and then removing the solvent.

[0090] The rest is the same as in Example 1.

[0091] Example 5

[0092] This embodiment provides a perovskite solar cell, the structure and preparation method of which differ from those in Example 1 in that the concentration of the linear polyethyleneimine modifier is 0.3 mg / mL.

[0093] The preparation method of the above-mentioned linear polyethyleneimine modifier includes the following steps:

[0094] Add 0.3 mg of linear polyethyleneimine to 1 mL of isopropanol and stir magnetically at 65 °C for 10 min to obtain the linear polyethyleneimine modifier.

[0095] The perovskite modification layer is formed by first coating a perovskite layer with a perovskite layer modifier and then removing the solvent.

[0096] The rest is the same as in Example 1.

[0097] Example 6

[0098] This embodiment provides a perovskite solar cell, the structure and preparation method of which differ from those in Example 1 in that the concentration of the linear polyethyleneimine modifier is 0.4 mg / mL.

[0099] The preparation method of the above-mentioned linear polyethyleneimine modifier includes the following steps:

[0100] Add 0.4 mg of linear polyethyleneimine to 1 mL of isopropanol and stir magnetically at 65 °C for 10 min to obtain the linear polyethyleneimine modifier.

[0101] The perovskite modification layer is formed by first coating a perovskite layer with a perovskite layer modifier and then removing the solvent.

[0102] The rest is the same as in Example 1.

[0103] Comparative Example 1

[0104] This comparative example provides a perovskite solar cell, which differs from Example 1 only in that it does not contain a perovskite modification layer; otherwise, it is identical to Example 1.

[0105] Comparative Example 2

[0106] This comparative example provides a perovskite solar cell, which differs from Example 1 only in that it does not contain a perovskite modification layer, and the perovskite layer contains linear polyethyleneimine.

[0107] The method for preparing the perovskite solar cell described above differs from that in Example 1 only in that step S3 is omitted. In step S2.1, a linear polyethyleneimine solution is added to the perovskite solution to make the concentration of linear polyethyleneimine 0.01 mg / mL. All other steps are the same as in Example 1.

[0108] Performance testing

[0109] The current density versus voltage (JV) characteristic curves, i.e. short-circuit current versus open-circuit voltage curves, of the perovskite solar cells of the examples and comparative examples were measured.

[0110] Efficiency tracking tests were performed on the unencapsulated perovskite solar cells of Example 1 and Comparative Example 1 under room temperature and nitrogen atmosphere conditions, i.e., the normalized efficiency-time curves were measured.

[0111] Steady-state photoluminescence analysis was performed on the modified perovskite layer of Example 1 and the unmodified perovskite layer of Comparative Example 1. The test structure of Example 1 was ITO / perovskite layer / perovskite modified layer, and the test structure of Comparative Example 1 was ITO / perovskite layer.

[0112] Transient photoluminescence analysis was performed on the modified perovskite layer of Example 1 and the unmodified perovskite layer of Comparative Example 1. The test structure of Example 1 was ITO / hole transport layer / perovskite layer / perovskite modified layer, and the test structure of Comparative Example 1 was ITO / hole transport layer / perovskite layer.

[0113] Contact angle tests were performed on the modified perovskite layer of Example 1 and the unmodified perovskite layer of Comparative Example 1.

[0114] XRD tracking tests were performed on the perovskite with modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1 under room temperature and air conditions.

[0115] The test results of the current density and voltage characteristic curves of the perovskite solar cells in the examples and comparative examples are shown in Table 1.

[0116] Table 1. Test results of current density and voltage characteristic curves.

[0117]

[0118] Table 1 shows that linear polyethyleneimine modifiers can increase the photoelectric conversion efficiency of perovskite solar cells from 19.31% to 20.68%–22.87%. This indicates that linear polyethyleneimine interacts with uncoordinated Pb at the perovskite grain boundaries and surface via hydroxyl groups. 2+ Interacting with each other, effectively passivating lead ion defects; also through secondary amine groups and unsaturated I - Hydrogen bonds are formed, inhibiting ion migration. This improves the photoelectric conversion efficiency of perovskite solar cells. As shown in Comparative Examples 2 and 1, adding linear polyethyleneimine solution to the perovskite layer may disrupt the crystallinity of the perovskite layer, leading to a decrease in the photoelectric conversion efficiency of the perovskite solar cell.

[0119] Figure 1 The graph shows a comparison of the JV curves of the perovskite solar cells prepared in Example 1 and Comparative Example 1. It can be seen from the graph that the perovskite solar cell obtained in Example 1 can increase the open-circuit voltage and fill factor, thereby improving the photoelectric conversion efficiency of the cell.

[0120] Figure 2The image shows the normalized efficiency-time curves for the perovskite solar cells of Example 1 and Comparative Example 1. From... Figure 2 It can be seen that when the perovskite solar cells of Example 1 and Comparative Example 1 were stored in a nitrogen environment at room temperature and the device efficiency was tracked, the PCE (photovoltaic conversion efficiency) of Comparative Example 1 without the perovskite modification layer decreased by 47% after 1032 hours, while the PCE of Example 1 with the perovskite modification layer remained at 75% after 2304 hours (96 days). This indicates that the linear polyethyleneimine of the present invention can effectively passivate lead ion defects through the hydroxyl groups, and the secondary amine groups and unsaturated I... - It forms hydrogen bonds, inhibits ion migration, and at the same time protects the perovskite layer from the influence of water molecules through its hydrophobic long alkyl chain, thereby improving the stability of perovskite solar cells.

[0121] Figure 3 The images show the steady-state photoluminescence spectra of the modified perovskite layer in Example 1 and the unmodified perovskite layer in Comparative Example 1. Figure 3 It can be seen that the fluorescence intensity of Example 1 is stronger than that of Comparative Example 1, which indicates that the linear polyethyleneimine of the present invention can effectively passivate defects in the perovskite layer and suppress nonradiative recombination at the perovskite interface and grain boundaries, thereby improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0122] Figure 4 The images show the transient photoluminescence spectra of the modified perovskite layer in Example 1 and the unmodified perovskite layer in Comparative Example 1. Figure 4 It can be seen that the average decay lifetime of charge carriers in Example 1 is lower than that in Comparative Example 1. This indicates that holes with the perovskite-modified layer can be transported more effectively from the perovskite layer to the hole transport layer. After the perovskite layer is photoexcited, the electron and hole separation efficiency is improved, which promotes the extraction and transport efficiency of charge carriers and suppresses nonradiative recombination at the perovskite interface and grain boundaries. Figure 3 The results are consistent, which in turn helps to improve the photoelectric conversion efficiency and stability of perovskite solar cells.

[0123] Figure 5 Figures a and b show the contact angle diagrams of the modified perovskite layer in Example 1 and the unmodified perovskite layer in Comparative Example 1, respectively. Figure 5 It can be seen that the contact angle of the modified perovskite layer is significantly larger than that of the unmodified perovskite layer, increasing from 62.5° to 78.1°. This indicates that in this invention, linear polyethyleneimine protects the perovskite layer from the erosion of water molecules and oxygen through hydrophobic long alkyl chains, thereby improving the hydrophobicity of the perovskite layer and thus improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0124] Figure 6The images show the XRD patterns of the perovskite films of Example 1 and Comparative Example 1 as they were placed in air over time. Figure 6 It can be seen that, under room temperature and air environment conditions, XRD tracking tests were performed on the perovskite layer with modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1. After 340 hours of storage, a new diffraction peak appeared at 10° in Comparative Example 1 without perovskite modification layer. This peak was inferred to be the peak of the inactive component of perovskite, that is, the perovskite began to change from the highly optically active black phase (α phase) to the weakly optically active yellow phase (δ phase). However, no such diffraction peak was found in Example 1 with perovskite modification layer after 1146 hours of storage. This indicates that the addition of linear polyethyleneimine in this invention can suppress the generation of the weakly optically active phase of perovskite, improve the hydrophobicity of the perovskite layer, and protect the perovskite layer from the erosion of water molecules and oxygen for a long time, thereby improving the stability of perovskite solar cells.

[0125] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A perovskite solar cell with an organic polymer-modified perovskite layer, wherein the device structure comprises, from bottom to top, a conductive glass layer, a hole transport layer, a perovskite layer, a perovskite modification layer, an electron transport layer, and a metal electrode layer; characterized in that, The structural formula of the perovskite layer is FA. x MA y PbI3, where x is 0.7~0.9 and y is 0.1~0.3, and the perovskite modification layer includes linear polyethyleneimine; the linear polyethyleneimine has the molecular structure shown in formula (1): Equation (1); The linear polyethyleneimine has an average molecular weight of 20,000 to 30,000; the perovskite modification layer is formed by first spin-coating a linear polyethyleneimine modifier onto a perovskite layer and then removing the solvent; the concentration of the linear polyethyleneimine modifier is 0.1 to 0.4 mg / mL.

2. The perovskite solar cell according to claim 1, characterized in that, The spin-coating volume of the linear polyethyleneimine modifier is 30~50 μL.

3. The perovskite solar cell according to claim 1, characterized in that, The spin-coating rate of the perovskite modified layer is 4000~6000 rpm.

4. The perovskite solar cell according to claim 1, characterized in that, The hole transport layer is made of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], PEDOT:PSS, and NiO. x At least one of [2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl]phosphoric acid and [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphoric acid.

5. The perovskite solar cell according to claim 1, characterized in that, The electron transport layer is a carbon-60 derivative.

6. A method for preparing a perovskite solar cell as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: A hole transport layer is fabricated on a conductive glass layer; S2: Fabrication of a perovskite layer on the hole transport layer; S3: Prepare a perovskite modification layer on the perovskite layer; S4: An electron transport layer is prepared on the perovskite modified layer; S5: Prepare a metal electrode layer on the electron transport layer to obtain the perovskite solar cell.

7. An application of a perovskite solar cell as described in any one of claims 1 to 5 in photovoltaic power plants, portable devices, military equipment, building-integrated photovoltaics, and indoor photovoltaics.

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