Perovskite solar cell with organic polymer molecule modified perovskite layer

Abstract

The invention discloses a perovskite solar cell with an organic polymer molecule modified perovskite layer, and belongs to the technical field of photovoltaic solar materials. The structure of the device sequentially 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 from bottom to top. The structural formula of the perovskite layer is FAxMAyPbI3, x ranges from 0.7 to 0.9, y ranges from 0.1 to 0.3, and the perovskite modified layer comprises linear polyethyleneimine. The linear polyethyleneimine has a molecular structure as shown in a formula (1). Hydroxyl in linear polyethyleneimine can be used as a Lewis base to interact with uncoordinated Pb < 2 + > on the grain boundary and the surface of perovskite, so that the lead ion defect can be effectively passivated; the secondary amine group can form a hydrogen bond with unsaturated I <-> to inhibit ion migration, and meanwhile, linear polyethyleneimine protects a perovskite layer from being influenced by water molecules through a hydrophobic long alkyl chain, so that the photoelectric conversion efficiency and stability of the perovskite solar cell are improved. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic solar energy materials, and more specifically, to a perovskite solar cell having a perovskite layer modified by an organic polymer molecule and a preparation method thereof. Background Art

[0002] Since the 21st century, human demand and dependence on energy have been increasing day by day. Non-renewable traditional fossil energy has been consumed rapidly, and the burning of fossil energy will also cause environmental pollution problems such as greenhouse effect and acid rain. Therefore, it is very important to develop and utilize renewable energy such as hydropower, wind power and solar energy to replace traditional fossil energy. Among them, solar energy resources are abundant, low-cost, inexhaustible, and have broad application prospects. Solar cells are a device that converts solar energy into electrical energy, and are currently the most efficient way to utilize solar energy. At present, the power conversion efficiency of perovskite solar cells has been greatly improved from 3.87% to 26.1%, and it also has the advantages of excellent device performance, low preparation cost, and solution preparation, showing great commercial potential.

[0003] However, since the perovskite layer is basically a polycrystalline perovskite film prepared by a solution method, there are usually a large number of defects in the perovskite body, at the surface interface and at the grain boundary, among which there are uncoordinated Pb 2+ , the presence of defects will lead to non-radiative recombination of carriers, affecting device performance. In addition, perovskite is an ionic semiconductor material, so its humidity stability is poor and it will decompose when exposed to water. At present, there are still many problems with perovskite solar cells, which is not conducive to their promotion and application. Therefore, it is of great significance to develop a perovskite layer modifier to improve the photoelectric conversion efficiency and stability of perovskite solar cells.

[0004] CN 117979781 A discloses an inverse perovskite solar cell, wherein the hole transport layer is formed by using functionalized nickel oxide nanoparticles, the functionalized nickel oxide nanoparticles are prepared by subjecting the nickel oxide nanoparticles to surface hydroxylation treatment and then grafting reaction with self-assembly materials, and the perovskite layer is composed of PbI 2 , FAI, MABr, MACl, CsI and PbBr 2 The prior art effectively improves the photoelectric efficiency of the inverted perovskite solar cell, but the invention does not improve the stability of the perovskite solar cell. Summary of the invention

[0005] The primary purpose of the present invention is to overcome the above-mentioned 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 a perovskite solar cell for use in photovoltaic power stations, portable devices, military equipment, building photovoltaic integration and indoor photovoltaics.

[0008] In order to achieve the above technical objectives, the present invention is implemented through the following technical solutions:

[0009] A perovskite solar cell with an organic polymer molecule 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 modified layer, an electron transport layer and a metal electrode layer; the structural formula of the perovskite layer is FA x MA y PbI 3 , wherein x is 0.7 to 0.9, y is 0.1 to 0.3, and the perovskite modification layer includes linear polyethyleneimine.

[0010] The present invention uses linear polyethyleneimine as a modifier to act on the perovskite layer. The hydroxyl groups in the linear polyethyleneimine can act as a Lewis base to bind to the uncoordinated Pb at the perovskite grain boundary and surface. 2+ Interaction occurs, effectively passivating lead ion defects, and the secondary amine group can interact with the unsaturated I - By forming hydrogen bonds, linear polyethyleneimine is retained between grain boundaries through bonding with perovskite, strengthening the links and forming an interpenetrating network, further inhibiting ion migration in the perovskite. In addition, linear polyethyleneimine forms a hydrophobic and stable modification layer on the surface of the perovskite layer through a hydrophobic long alkyl chain, 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 the invention is used for improving the photoelectric conversion efficiency and stability of perovskite solar cells.

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

[0013] Specifically, the perovskite modification layer is formed by first spin-coating the linear polyethyleneimine modification agent on 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 to 50 μL.

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

[0017] Specifically, the spin coating time of the perovskite modification layer is 25 to 35 seconds.

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

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

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

[0021] Specifically, the material of the hole transport layer is poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], PEDOT:PSS, NiO x , [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) at least one of.

[0022] More specifically, the hole transport layer is NiO x and [2-(3,6-dimethyl-9H-carbazol-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 butyric acid methyl ester, [6,6]-thienyl C61 butyric acid methyl ester, [6,6]-phenyl-C61-butyric acid n-octyl ester or [6,6]-phenyl-C61-butyric acid 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 method for preparing the above-mentioned perovskite solar cell comprises the following steps:

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

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

[0030] S3: preparing a perovskite modified layer on the perovskite layer;

[0031] S4: preparing an electron transport layer on the perovskite modified layer;

[0032] S5: Preparing 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, the step S0 is as follows: ultrasonically cleaning the conductive glass with an ITO detergent, deionized water, acetone and isopropyl alcohol alternately, and drying the conductive glass to obtain a conductive glass layer.

[0035] Specifically, the step S1 is as follows: subjecting the conductive glass layer to ultraviolet ozone treatment, and spin coating a hole transport layer solution prepared with hole transport layer materials on the surface of the conductive glass to obtain a hole transport layer.

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

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

[0038] More specifically, the materials of the perovskite are formamidine hydroiodide (FAI), methylammonium iodide (MAI) and lead iodide (PbI 2 ).

[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, the spin coating rate in step S2 is 1000-5000 rpm, and the spin coating time is 5-35 s.

[0041] Specifically, the step S3 is as follows: spin coating a linear polyethyleneimine modifier on the perovskite layer, heating to form a film, and obtaining a perovskite modified layer.

[0042] Specifically, the step S4 is as follows: preparing the material of the electron transport layer into an electron transport layer solution and spin coating it on the surface of the perovskite modified layer, and then spin coating bathocuproine (BCP) to obtain the electron transport layer.

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

[0044] Specifically, the step S5 is as follows: 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 use of the perovskite solar cell in photovoltaic power stations, portable devices, military equipment, building photovoltaic integration and indoor photovoltaics.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The present invention uses linear polyethyleneimine as a modifier to act on the perovskite layer. The hydroxyl groups in the linear polyethyleneimine can act as a Lewis base to bind to the uncoordinated Pb at the perovskite grain boundary and surface. 2+ Interaction occurs, effectively passivating lead ion defects, and the secondary amine group can interact with the unsaturated I - Hydrogen bonds are formed to inhibit 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 the present invention is increased from 19.31% to 20.68% to 22.87%. After being placed at room temperature for 2304 hours (96 days), the photoelectric conversion efficiency still maintains the original 75%. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0051] Figure 3 Steady-state photoluminescence spectra of the perovskite layer with a modified 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 These are contact angle diagrams of the perovskite layer with a modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1. Figures a and b are contact angle diagrams of Comparative Example 1 and Example 1, respectively.

[0054] Figure 6 XRD diagrams of the perovskite films of Example 1 and Comparative Example 1 changing over time when placed in air. DETAILED DESCRIPTION

[0055] The present invention is further described below in conjunction with examples. These examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually carried out according to conventional conditions in the art or according to the conditions recommended by the manufacturer; the raw materials, reagents, etc. used, unless otherwise specified, are all raw materials and reagents that can be obtained from commercial channels such as conventional markets. Any non-substantial changes and substitutions made by those skilled in the art on the basis of the present invention belong to the scope of protection claimed by the present invention.

[0056] The linear polyethyleneimine used in Examples 1 to 6 and Comparative Example 2 has a molecular structure shown in formula (1):

[0057]

[0058] Among them, Mw is 25000.

[0059] Example 1

[0060] This embodiment provides a perovskite solar cell, which includes, 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 structural formula of the perovskite layer is FA 0.8 MA 0.2 PbI 3 , the perovskite modification layer includes linear polyethyleneimine.

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

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

[0063] The preparation method of the linear polyethyleneimine modifier comprises the following steps:

[0064] 0.25 mg of linear polyethyleneimine was added to 1 mL of isopropanol and magnetically stirred at 65° C. for 10 min to obtain a linear polyethyleneimine modifier.

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

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

[0067] S1: The conductive glass layer of S1 was placed in a UV-ozone cleaning machine for UV-ozone treatment. After the treatment, 40 μL of 15 mg / mL NiO was spin-coated on the surface of the conductive glass layer in air. xThe solution was spin-coated at a speed of 4000 rpm for 30 seconds and annealed on a heating table for 30 minutes. It was then transferred to a glove box with a nitrogen atmosphere and heated to 4000 rpm for 30 seconds. x 40 μL of 0.4 mg / mL Me-2PACz solution was spin-coated on the surface at a speed of 4000 rpm for 30 s. After the spin coating, the surface was transferred to a heating station for heating to obtain a hole transport layer.

[0068] S2.1: PbI 2 , FAI, and MAI were mixed at a molar ratio of 5:4:1, dissolved in 1 mL of DMF-DMSO, and the mixed solution was stirred for 3 h to prepare a perovskite solution, wherein: V(DMF):V(DMSO)=4:1;

[0069] S2.2 Spin-coat 65 μL of perovskite solution on the surface of the hole transport layer at a rate of 1000 rpm for 5 s, then at a rate of 5000 rpm for 35 s, then drop chlorobenzene, and then transfer to a heating stage for heating to obtain a perovskite layer;

[0070] S3: Spin-coat 40 μL of perovskite layer modifier on the perovskite layer at a speed of 5000 rpm for 30 seconds, and then transfer to a heating stage for heating to form a film, thereby obtaining a perovskite modified layer;

[0071] S4: 23 mg of the electron transport layer material [6,6]-phenyl C61 butyric acid 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 on the surface of the perovskite modified layer at a speed of 3000 rpm for 30 s. After the spin coating, it was transferred to a heating table for heating, and then 45 μL of 2.5 mg / mL bathocuproin (BCP) was spin-coated at a speed of 5000 rpm for 30 s to obtain an 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, evaporate the silver metal electrode, and obtain a perovskite solar cell.

[0073] Example 2

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

[0075] The preparation method of the linear polyethyleneimine modifier comprises the following steps:

[0076] 0.1 mg of linear polyethyleneimine was added to 1 mL of isopropanol and magnetically stirred at 65° C. for 10 min to obtain a linear polyethyleneimine modifier.

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

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

[0079] Example 3

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

[0081] The preparation method of the linear polyethyleneimine modifier comprises the following steps:

[0082] 0.15 mg of linear polyethyleneimine was added to 1 mL of isopropanol and magnetically stirred at 65° C. for 10 min to obtain a linear polyethyleneimine modifier.

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

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

[0085] Example 4

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

[0087] The preparation method of the linear polyethyleneimine modifier comprises the following steps:

[0088] 0.2 mg of linear polyethyleneimine was added to 1 mL of isopropanol and magnetically stirred at 65° C. for 10 min to obtain a linear polyethyleneimine modifier.

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

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

[0091] Example 5

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

[0093] The preparation method of the linear polyethyleneimine modifier comprises the following steps:

[0094] 0.3 mg of linear polyethyleneimine was added to 1 mL of isopropanol and magnetically stirred at 65° C. for 10 min to obtain a linear polyethyleneimine modifier.

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

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

[0097] Example 6

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

[0099] The preparation method of the linear polyethyleneimine modifier comprises the following steps:

[0100] 0.4 mg of linear polyethyleneimine was added to 1 mL of isopropanol and magnetically stirred at 65° C. for 10 min to obtain a linear polyethyleneimine modifier.

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

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

[0103] Comparative Example 1

[0104] This comparative example provides a perovskite solar cell, which is different from Example 1 only in that it does not contain a perovskite modification layer, and the rest is consistent with Example 1.

[0105] Comparative Example 2

[0106] This comparative example provides a perovskite solar cell, which is different 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 is different from that of Example 1 only in that step S3 is not included, and a linear polyethyleneimine solution is added to the perovskite solution in step S2.1 to make the concentration of the linear polyethyleneimine 0.01 mg / mL, and the rest is the same as that of Example 1.

[0108] Performance Testing

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

[0110] Under room temperature and nitrogen environment conditions, the efficiency tracking test of the unpackaged perovskite solar cells of Example 1 and Comparative Example 1 was performed, that is, the normalized efficiency-time curve was measured.

[0111] Steady-state photoluminescence analysis was performed on the perovskite layer with a modified layer in Example 1 and the unmodified perovskite layer in 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 perovskite layer with a modified layer in Example 1 and the unmodified perovskite layer in 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] The contact angle test was performed on the perovskite layer with the modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1.

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

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

[0116] Table 1 Current density and voltage characteristic curve test results

[0117]

[0118] As shown in Table 1, the linear polyethyleneimine modifier can increase the photoelectric conversion efficiency of perovskite solar cells from 19.31% to 20.68% to 22.87%, which indicates that the linear polyethyleneimine can bind to the uncoordinated Pb at the perovskite grain boundary and surface through the hydroxyl group. 2+ Interaction occurs, effectively passivating lead ion defects; it also interacts with unsaturated I - Hydrogen bonds are formed to inhibit ion migration. This improves the photoelectric conversion efficiency of the perovskite solar cell. As shown in Comparative Example 2 and Comparative Example 1, adding a linear polyethyleneimine solution to the perovskite layer may destroy the crystallization of the perovskite layer, thereby reducing the photoelectric conversion efficiency of the perovskite solar cell.

[0119] Figure 1 It is a comparison diagram of the JV curves of the perovskite solar cells prepared in Example 1 and Comparative Example 1. It can be seen from the figure 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 21 is a normalized efficiency-time curve of the perovskite solar cell of Example 1 and Comparative Example 1. Figure 2 It can be seen that the perovskite solar cells of Example 1 and Comparative Example 1 were stored in a nitrogen environment at room temperature, and the efficiency tracking test of the devices was performed. The PCE (photovoltaic conversion efficiency) of Comparative Example 1 without a perovskite modification layer decayed by 47% after 1032 hours, while the PCE of Example 1 containing a perovskite modification layer remained at 75% after 2304 hours (96 days). This shows that the linear polyethyleneimine of the present invention can effectively passivate lead ion defects through hydroxyl groups, and the secondary amine groups and unsaturated I - It forms hydrogen bonds, inhibits ion migration, and protects the perovskite layer from water molecules through its hydrophobic long alkyl chains, thereby improving the stability of perovskite solar cells.

[0121] Figure 3 The steady-state photoluminescence spectra of the perovskite layer with the modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1 are shown. 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 the defects in the perovskite layer and inhibit the non-radiative recombination at the perovskite interface and grain boundary, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0122] Figure 4 Figure 1 is a transient photoluminescence spectrum of the perovskite layer with a modified 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 the carriers in Example 1 is lower than that in Comparative Example 1, which indicates that the holes in the perovskite modified layer can be more effectively transferred from the perovskite layer to the hole transport layer. After the perovskite layer is excited by light, the separation efficiency of electrons and holes is improved, which promotes the extraction and transmission efficiency of carriers and inhibits the non-radiative recombination at the perovskite interface and grain boundary. Figure 3 The results are consistent, which is beneficial to improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0123] Figure 5 Figures a and b are contact angle diagrams of the perovskite layer with a modified 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 perovskite layer with the modified layer is significantly increased compared with the unmodified perovskite layer, increasing from 62.5° to 78.1°. This shows that the linear polyethyleneimine in the present invention protects the perovskite layer from the erosion of water molecules and oxygen through the hydrophobic long alkyl chain, thereby improving the hydrophobicity of the perovskite layer, which is beneficial to improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0124] Figure 6The XRD patterns of the perovskite films of Example 1 and Comparative Example 1 that change with time when placed in air. Figure 6 It can be seen that under room temperature and air environment conditions, XRD tracking tests were performed on the perovskite with a modified layer in Example 1 and the unmodified perovskite layer in Comparative Example 1. When placed for 340 hours, Comparative Example 1 without a perovskite modified layer showed a new diffraction peak at 10°, which was inferred to be the peak of the inactive component of the perovskite, that is, the perovskite began to transform from a black phase (α phase) with high optical activity to a yellow phase (δ phase) with weak optical activity, while Example 1 containing a perovskite modified layer did not find this diffraction peak after being placed for 1146 hours, which shows that the addition of linear polyethyleneimine of the present invention can inhibit the generation of a weak optically active phase of perovskite, improve the hydrophobicity of the perovskite layer, and protect the perovskite layer from erosion by water molecules and oxygen for a long time, thereby achieving improved 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 embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A perovskite solar cell with an organic polymer molecule 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 modified 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, wherein x is 0.7 to 0.9, y is 0.1 to 0.3, and the perovskite modification layer includes linear polyethyleneimine.

2. The perovskite solar cell according to claim 1, characterized in that: The average weight molecular weight of the linear polyethyleneimine is 20,000 to 30,000.

3. The perovskite solar cell according to claim 1, characterized in that: The perovskite modification layer is formed by first spin coating a linear polyethyleneimine modification agent on the perovskite layer and then removing the solvent.

4. The perovskite solar cell according to claim 4, characterized in that: The concentration of the linear polyethyleneimine modifier is 0.1-0.4 mg / mL.

5. The perovskite solar cell according to claim 4, characterized in that: The spin coating volume of the linear polyethyleneimine modifier is 30-50 μL.

6. The perovskite solar cell according to claim 4, characterized in that: The spin coating rate of the perovskite modification layer is 4000-6000 rpm.

7. 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, NiO x , [2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl]phosphoric acid and [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphoric acid.

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

9. A method for preparing a perovskite solar cell according to any one of claims 1 to 8, characterized in that: The steps include: S1: preparing a hole transport layer on the conductive glass layer; S2: preparing a perovskite layer on the hole transport layer; S3: preparing a perovskite modified layer on the perovskite layer; S4: preparing an electron transport layer on the perovskite modified layer; S5: preparing a metal electrode layer on the electron transport layer to obtain the perovskite solar cell.

10. Use of the perovskite solar cell according to any one of claims 1 to 8 in photovoltaic power stations, portable devices, military equipment, building photovoltaic integration and indoor photovoltaics.

Images