Perovskite solar cell, preparation method thereof and photovoltaic module

Abstract

The invention relates to the technical field of solar cells, and discloses a perovskite solar cell, a preparation method thereof and a photovoltaic module, the perovskite solar cell comprises a hole transport layer, a perovskite layer and a self-assembly monomolecular layer located between the hole transport layer and the perovskite layer; wherein the material of the self-assembled monomolecular layer comprises a polymer formed by polymerizing an electron donating material and an electron withdrawing material. The perovskite solar cell has a relatively high hole transport rate and relatively few interface defects, is beneficial to reducing non-radiative recombination, and improves the photoelectric conversion performance and stability of the perovskite solar cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a perovskite solar cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] In the perovskite solar cell, a carbazole small molecule layer is arranged between the perovskite layer and the hole transport layer, which can effectively improve the poor energy level matching of the perovskite layer and the hole transport layer, but the contact performance of the substance with the perovskite layer is poor, so that there are many defects in the interface, which affects the transport performance of the carriers. SUMMARY

[0003] The embodiments of the present application disclose a perovskite solar cell, a preparation method thereof and a photovoltaic module, the perovskite solar cell has a high hole transport rate, fewer interface defects, helps to reduce non-radiative recombination, and improves the photoelectric conversion performance and stability of the perovskite solar cell.

[0004] In a first aspect, the embodiments of the present application disclose a perovskite solar cell, comprising: a hole transport layer, a perovskite layer, and a self-assembled monolayer between the hole transport layer and the perovskite layer.

[0005] The material of the self-assembled monolayer includes a polymer formed by polymerization of an electron-donating material and an electron-withdrawing material.

[0006] Further, the molar ratio of the electron-donating material to the electron-withdrawing material is 1:1 to 1:1.2.

[0007] Further, the molecular weight of the polymer is 3W to 4W.

[0008] Further, the active group of the polymer includes at least one of a Lewis acid, a Lewis base, a carbonyl group, and an amine group.

[0009] Further, the electron-withdrawing material includes at least one of:

[0010]

[0011]

[0012] wherein R0, R1, R2, and R3 are all first alkyl groups, and the first alkyl group includes -CH3, -C2H5, -C3H7, -C4H9, -C5H 11 , -C6H 13 , -C7H 15 , -C8H 17 , -C9H 19 , or -C10 H 21 ;

[0013] The electron-donating material includes at least one of the following;

[0014]

[0015]

[0016] wherein R4, R5, R6, R7, R8 are all second alkyl groups, the second alkyl group includes -CH3, -C2H5, -C3H7, -C4H9, -C5H 11 , -C6H 13 , -C7H 15 , -C8H 17 , -C9H 19 , or -C 10 H 21 .

[0017] Further, the energy level difference between the self-assembled monolayer and the perovskite layer is 0.1 eV to 0.3 eV; and / or,

[0018] The energy level difference between the hole transport layer and the self-assembled monolayer is 0.4 eV to 0.6 eV.

[0019] Further, the perovskite solar cell further comprises a substrate, the self-assembled monolayer is arranged close to the substrate, and the perovskite layer is located on the side surface of the self-assembled monolayer away from the substrate.

[0020] Further, the perovskite solar cell further comprises a substrate, the substrate has a pyramid structure, the self-assembled monolayer has a textured structure, the textured structure of the self-assembled monolayer is consistent with the pyramid structure of the substrate, the longest side length of the bottom of the textured structure of the self-assembled monolayer is 1 μm to 3 μm, and the height of the textured structure of the self-assembled monolayer is 1 μm to 3 μm.

[0021] Further, the material of the hole transport layer includes at least one of nickel oxide, molybdenum oxide, and vanadium oxide; and / or,

[0022] The thickness of the hole transport layer is 20 nm to 30 nm; and / or,

[0023] The thickness of the perovskite layer is 450 nm to 550 nm; and / or,

[0024] The electron-donating material includes dithiophene pyrrolidone, and the electron-accepting material includes thienopyrrolidone.

[0025] Further, the perovskite solar cell is a stacked cell, the perovskite solar cell comprises a substrate, the substrate comprises a bottom cell, an electron-hole recombination layer arranged on the bottom cell, the perovskite solar cell further comprises a first transport layer, a second transport layer, a transparent conductive layer and an electrode, the first transport layer is arranged on a side of the electron-hole recombination layer away from the bottom cell, the perovskite layer is arranged between the first transport layer and the second transport layer, the second transport layer is arranged on a side of the perovskite layer away from the first transport layer, the transparent conductive layer is arranged on a side of the second transport layer away from the perovskite layer, the electrode comprises a first electrode and a second electrode, the first electrode is arranged on a side of the transparent conductive layer away from the second transport layer, and the second electrode is arranged on a side of the bottom cell away from the electron-hole recombination layer; wherein one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode, one of the first transport layer and the second transport layer is the hole transport layer, and the other is the electron transport layer.

[0026] Alternatively, the perovskite solar cell is a single-junction cell, the perovskite solar cell comprises a substrate, the substrate is a transparent conductive substrate, the perovskite solar cell further comprises a first transport layer, a second transport layer, a first electrode and a second electrode, the first transport layer is arranged on the transparent conductive substrate, the perovskite layer is arranged between the first transport layer and the second transport layer, the second transport layer is arranged on a side of the perovskite layer away from the first transport layer, the first electrode is arranged on a side of the second transport layer away from the perovskite layer, and the second electrode is arranged on a side of the transparent conductive substrate away from the first transport layer; wherein one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode, one of the first transport layer and the second transport layer is the hole transport layer, and the other is the electron transport layer.

[0027] In a second aspect, the embodiments of the present application disclose a preparation method of a perovskite solar cell, the preparation method comprises the following steps:

[0028] An self-assembled monolayer is prepared between the hole transport layer and the perovskite layer; wherein the material of the self-assembled monolayer comprises a polymer formed by polymerization of a donor material and an acceptor material;

[0029] Post-processing to obtain the perovskite solar cell according to any one of the first aspect.

[0030] Further, the preparation method comprises the following steps:

[0031] The self-assembled monolayer is prepared on the hole transport layer: a solution containing the polymer is coated on the hole transport layer;

[0032] annealing to obtain the self-assembled monolayer;

[0033] preparing the perovskite layer on the self-assembled monolayer.

[0034] Further, the mass concentration of the polymer is 0.8 mg / mL-1.2 mg / mL.

[0035] Further, the solvent in the solution comprises a first solvent and a second solvent, the volume ratio of the first solvent and the second solvent is 0.5:1-1:1, the first solvent comprises at least one of chloroform and chloroform, and the second solvent is ethanol; and / or,

[0036] In the step of annealing, the temperature of annealing is 90°C-110°C, and the time is 5 min-15 min.

[0037] Further, before the step of preparing the self-assembled monolayer on the hole transport layer, the preparation method further comprises preparing the polymer, and the step of preparing the polymer comprises:

[0038] After the mixed solution containing the electron donor material, the electron acceptor material, and the catalyst is reacted, a polymer precursor is obtained;

[0039] The polymer precursor is dispersed in a solvent and filtered to obtain the polymer.

[0040] Further, in the step of obtaining the polymer precursor, the catalyst is tris(dibenzylideneacetone)dipalladium and tri(o-tolyl)phosphine, and the molar ratio of the tris(dibenzylideneacetone)dipalladium to the tri(o-tolyl)phosphine is 1:3-1:5; and / or,

[0041] In the step of obtaining the polymer precursor, the mixed solution is reacted at a temperature of 100°C-120°C in the dark for 45 h-50 h; and / or,

[0042] The step of obtaining the polymer comprises:

[0043] The polymer precursor is dispersed in a dispersion liquid to form an extraction liquid;

[0044] The extraction liquid is subjected to Soxhlet extraction and silica gel column filtration to remove impurities and oligomers in the extraction liquid, and the polymer is obtained after precipitation, concentration, and filtration.

[0045] Further, the step of preparing the perovskite layer on the self-assembled monolayer comprises:

[0046] A lead skeleton layer is prepared on the self-assembled monolayer by co-evaporation;

[0047] The cation solution is spin-coated on the lead framework layer, and the perovskite layer is obtained after annealing.

[0048] Further, in the step of preparing the lead framework layer on the self-assembled monolayer by co-evaporation, the evaporation source material of the lead framework layer comprises PbX and CsX, and the evaporation rate is X ions in the PbX and the CsX comprise at least one of I ions, Br ions, and Cl ions; and / or,

[0049] In the step of spin-coating the cation solution on the lead framework layer, the cation solution comprises at least two of FAI, FABr, MABr, and MACl;

[0050] The molar concentration of the FAI is 0.3 mol / L to 0.6 mol / L; and / or,

[0051] The molar concentration of the FABr is 0 mol / L to 0.2 mol / L; and / or,

[0052] The molar concentration of the MABr is 0 mol / L to 0.2 mol / L; and / or,

[0053] The molar concentration of the MACl is 0.05 mol / L to 0.25 mol / L.

[0054] In a third aspect, the embodiments of the present application disclose a photovoltaic module, comprising the perovskite solar cell of any one of the first aspect, or the perovskite solar cell prepared by the preparation method of any one of the second aspect.

[0055] Compared with the prior art, the present application has the beneficial effects that:

[0056] The present application provides a perovskite solar cell and a preparation method thereof, and a photovoltaic module. By introducing a self-assembled monolayer formed by an electron-accepting material and an electron-donating material into a hole transport layer and a perovskite layer, the rate of hole transport is improved, interface defects are passivated, non-radiative recombination is reduced, and the photoelectric conversion performance and stability of the perovskite solar cell are improved.

[0057] Specifically, the self-assembled monolayer is arranged between the hole transport layer and the perovskite layer, and the material of the self-assembled monolayer includes a polymer formed by polymerization of the electron-donating material and the electron-accepting material, so that the push-pull effect of the electron-donating material and the electron-accepting material can be effectively utilized to form a channel conducive to hole transport in the self-assembled monolayer, thereby improving the hole transport capability; and the polymer has high thermal stability, so that the self-assembled monolayer prepared has high thermal stability, thereby helping to improve the stability of the perovskite solar cell. In addition, the self-assembled monolayer has a dipole moment, and the presence of the dipole moment causes a certain electrostatic repulsion between the polymers, which blocks the agglomeration between the polymers, not only making the self-assembled monolayer have good linearity and small steric hindrance, but also making the film layer have good compactness, so that the matching degree of the interface between the self-assembled monolayer and the hole transport layer and the perovskite layer is higher. BRIEF DESCRIPTION OF DRAWINGS

[0058] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without creative labor based on the embodiments in the present application also belong to the protection scope of the present application.

[0059] Figure 1 is a structure schematic diagram of a laminated perovskite solar cell provided by the present application (wherein the first transport layer is a hole transport layer, and the second transport layer is an electron transport layer);

[0060] Figure 2 is a synthesis route diagram of PDTP-TPD provided by the first embodiment of the present application;

[0061] Figure 3 is a molecular configuration diagram of PDTP-TPD provided by the first embodiment of the present application.

[0062] Figure: 1, substrate; 11, bottom cell; 12, electron-hole recombination layer; 2, first transport layer; 3, perovskite layer; 4, second transport layer; 5, transparent conductive layer; 6, electrode; 61, first electrode; 62, second electrode; 7, self-assembled monolayer; 8, passivation layer; 9, buffer layer; 10, antireflection layer. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor also belong to the protection scope of the present application.

[0064] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "transverse", "longitudinal", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not intended to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0065] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned partial terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0066] In addition, the terms "first", "second", and the like are mainly used to distinguish different devices, elements or components (the specific types and structures can be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise stated, the meaning of "multiple" is two or more.

[0067] The technical solutions provided by the present application will be further described below in conjunction with the embodiments and the drawings.

[0068] In the perovskite solar cell, there are usually defects such as unsaturated bonds and vacancies at the interface between the perovskite layer and the hole transport layer, which can become recombination centers for carriers and affect the performance of the perovskite solar cell. In addition, due to the poor energy level matching between the perovskite layer and the hole transport layer, the transmission resistance of the holes is high, thereby reducing the extraction and transmission efficiency of the holes and affecting the performance of the perovskite solar cell.

[0069] By arranging a layer of carbazole small molecules between the perovskite layer and the hole transport layer, the problem of poor energy level matching between the perovskite layer and the hole transport layer can be effectively improved. However, since the carbazole material has amphiphilic properties, it is prone to aggregation, which makes the compactness of the film layer of the carbazole small molecules poor, resulting in more interface defects with the perovskite layer and the hole transport layer, thereby increasing the probability of carrier recombination. And it is more susceptible to the invasion of oxygen, moisture and the like, thereby making the stability of the perovskite solar cell worse.

[0070] Based on the above problems, the embodiments of the present application provide a perovskite solar cell and a preparation method thereof, and a photovoltaic module. The perovskite solar cell has high hole transport capacity and fewer interface defects, which can effectively improve the photoelectric conversion performance and stability of the perovskite solar cell.

[0071] In a first aspect, the embodiments of the present application disclose a perovskite solar cell, which comprises a hole transport layer, a perovskite layer and a self-assembled monolayer between the hole transport layer and the perovskite layer.

[0072] The material of the self-assembled monolayer comprises a polymer formed by polymerization of an electron-donating material and an electron-withdrawing material.

[0073] The self-assembled monolayer is arranged between the hole transport layer and the perovskite layer, and the material of the self-assembled monolayer comprises a polymer formed by polymerization of an electron-donating material and an electron-withdrawing material, so that the push-pull effect of the electron-donating material and the electron-withdrawing material can be effectively utilized to form a channel in the self-assembled monolayer, which is beneficial to the transport of holes, thereby improving the transport capacity of holes. The polymer has high thermal stability, so that the self-assembled monolayer prepared has high thermal stability, thereby helping to improve the stability of the perovskite solar cell. In addition, the self-assembled monolayer has a dipole moment, and the existence of the dipole moment causes a certain electrostatic repulsion between the polymers, which blocks the agglomeration between the polymers, so that the self-assembled monolayer has good linearity, small steric hindrance, and good compactness of the film layer, thereby improving the matching of the interface between the self-assembled monolayer and the hole transport layer and the perovskite layer.

[0074] The electron-donating material refers to a substance containing an electron-donating group, and the electron-withdrawing material refers to a substance containing an electron-withdrawing group.

[0075] Further, by controlling the molar ratio of the electron-donating material to the electron-withdrawing material to be 1:1-1:1.2, the energy level of the self-assembled monolayer, the perovskite layer and the hole transport layer has high matching degree, the energy barrier in the hole transport process is reduced, the transport capacity of holes is further improved, the interface defects are passivated, the charge recombination at the interface is reduced, and the thermal stability and the photoelectric conversion efficiency of the perovskite solar cell are improved. In addition, by controlling the molar ratio within the above range, the dipole moment in the self-assembled monolayer can be further adjusted, so that the linearity of the self-assembled monolayer is higher, the steric hindrance is further reduced, and the compactness of the film layer of the self-assembled monolayer is better, thereby improving the matching of the interface between the self-assembled monolayer and the hole transport layer and the perovskite layer, and reducing the interface defects.

[0076] Further, the molecular weight of the polymer is 3W-4W; when the molecular weight of the polymer is controlled within the above range, on the one hand, the solubility of the polymer is better, thereby ensuring that the prepared self-assembled monolayer film layer has better compactness and fewer defects, thereby reducing the recombination center of carriers, and on the other hand, it is helpful to form a more ordered molecular packing structure and the interaction between the molecules is stronger, so as to not only improve the hole transport efficiency and reduce the recombination of holes, but also promote the formation of a more stable chemical and physical combination between the self-assembled monolayer and the hole transport layer and the perovskite layer, and improve the adhesion of the interface.

[0077] Illustratively, the molecular weight of the polymer can be measured by a high-temperature gel chromatograph (Gel Permeation Chromatography, GPC).

[0078] In addition, the active groups of the polymer include at least one of a Lewis acid, a Lewis base, a carbonyl group, and an amine group. Among them, the Lewis acid can act as an electron-withdrawing group, and the Lewis base can act as an electron-donating group; when the polymer contains both of these two active groups, it not only helps to promote the formation of the polymer, but also can covalently coordinate with the uncoordinated halogen or lead ion in the perovskite layer, thereby achieving the effect of defect passivation, and further improving the performance of the perovskite solar cell; the carbonyl group can combine with the uncoordinated cation defects in the perovskite layer, thereby achieving the effect of passivation; and the amine group can combine with the uncoordinated halogen ion to fill the iodine vacancy defects, thereby achieving the effect of passivation.

[0079] In addition, the electron-withdrawing material includes at least one of

[0080]

[0081]

[0082] wherein R0, R1, R2, and R3 are all first alkyl groups, and the first alkyl group includes -CH3, -C2H5, -C3H7, -C4H9, -C5H 11 , -C6H 13 , -C7H 15 , -C8H 17 , -C9H 19 , or -C 10 H 21 ;

[0083] The electron-donating material includes at least one of

[0084]

[0085]

[0086] wherein R4, R5, R6, R7, R8 are all second alkyl, and the second alkyl includes -CH3, -C2H5, -C3H7, -C4H9, -C5H 11 , -C6H 13 , -C7H 15 , -C8H 17 , -C9H 19 , or -C 10 H 21 .

[0087] wherein, for example, R0, R1, R2, R3 in the electron-accepting material, the alkyl represented by R0, R1, R2, R3 can be the same or different. When the structure formula in the electron-accepting material has R0, exemplarily, R0 is -CH3, -C2H6, or -C6H 13 , etc. When the structure formula in the electron-accepting material has R1, R2, exemplarily, the alkyl of R1, R2 can be the same type of alkyl, exemplarily, R1, R2 are both -CH3; or the alkyl of R1, R2 is different type of alkyl, exemplarily, R1 is -C2H6, R2 is -C6H 13 , etc. When the structure formula in the electron-accepting material has R1, R2, R3, exemplarily, R1, R2, R3 can be the same type of alkyl, exemplarily, R1, R2, R3 can all be -CH3; or two of R1, R2, R3 are the same type of alkyl, exemplarily, R1 and R2 are both -CH3, R3 is -C6H 13 , etc.; or the alkyl type of R1, R2, R3 is all different, exemplarily, R1 is -C2H6, R2 is -C6H 13 , R3 is -CH3.

[0088] In addition, R4, R5, R6, R7, R8 in the electron-donating material have the same meaning, which will not be described herein.

[0089] The polymer formed by the above-mentioned substance has high energy level matching, high linearity, and can effectively passivate interface defects and improve the bonding force of the interface, thereby effectively improving the photoelectric conversion performance of the perovskite solar cell.

[0090] Further, the energy level difference between the self-assembled monolayer and the perovskite layer is 0.1 eV to 0.3 eV; and / or the energy level difference between the hole transport layer and the self-assembled monolayer is 0.4 eV to 0.6 eV.

[0091] When the energy level difference is within the above range, the energy level of the self-assembled monolayer is more suitable for matching the energy levels of the perovskite layer and the hole transport layer, which helps to reduce the transport barrier and improve the efficiency of hole transport.

[0092] In an alternative embodiment, the perovskite solar cell further comprises a substrate, the perovskite layer is arranged close to the substrate, the self-assembled monolayer is arranged on the side of the perovskite layer away from the substrate, and the hole transport layer is arranged on the side surface of the self-assembled monolayer away from the perovskite layer.

[0093] In another alternative embodiment, the self-assembled monolayer is arranged close to the substrate, the perovskite layer is arranged on the side surface of the self-assembled monolayer away from the substrate, and the hole transport layer is arranged on the side surface of the self-assembled monolayer close to the substrate. Since the self-assembled monolayer is arranged below the perovskite layer, the self-assembled monolayer promotes the crystallization of the perovskite layer during the preparation of the perovskite layer, so that the prepared perovskite layer has fewer defects, thereby helping to improve the quality of the crystal of the perovskite layer.

[0094] Further, the perovskite solar cell further comprises a substrate, the substrate has a pyramid structure, the self-assembled monolayer has a pyramidal structure consistent with the pyramid structure of the substrate, the longest side length of the base of the pyramidal structure of the self-assembled monolayer is 1 μm to 3 μm, and the height of the pyramidal structure of the self-assembled monolayer is 11 μm to 3 μm.

[0095] Since the self-assembled monolayer has high linearity, it has high compatibility with the substrate. When the substrate has a pyramid structure, the pyramidal structure on the self-assembled monolayer is consistent with the pyramid structure of the substrate, so that the pyramidal structure of the finally prepared perovskite solar cell has high light trapping effect. In addition, the high compatibility also helps to reduce the existence of interface defects, thereby reducing the recombination loss of carriers.

[0096] Further, the material of the hole transport layer includes at least one of nickel oxide, molybdenum oxide, and vanadium oxide. Since nickel oxide has wide sources and high chemical stability, when the material of the hole transport layer is nickel oxide, the stability of the hole transport layer is good and the production cost is relatively low.

[0097] In addition, the thickness of the hole transport layer is 20 nm to 30 nm. When the thickness of the hole transport layer is within the above range, the transport distance of the holes is appropriate, which helps to reduce the recombination loss during the transport process.

[0098] Furthermore, the thickness of the perovskite layer is 450 nm to 550 nm. When the thickness of the perovskite layer is within the above range, it can effectively absorb sunlight, which helps to generate photo-generated carriers and effectively control the recombination loss of carriers during transport, thereby improving the performance of the perovskite solar cell.

[0099] In addition, the electron-donating material includes Dithieno(3,2-b:2',3'-d)pyrrol-2,5-dione (DTP), and the electron-accepting material includes Thieno(3,4-c)pyrrole-4,6-dione (TPD). When the above two materials are polymerized, the polymer formed by the polymerization is Poly-(Dithieno(3,2-b:2',3'-d)pyrrol-2,5-dione)-(Thieno(3,4-c)pyrrole-4,6-dione) (PDTP-TPD).

[0100] In an alternative embodiment, the solar cell in the embodiments of the present application can be a stacked cell. As shown in the following, the perovskite solar cell is further introduced. Figure 1

[0101] The perovskite solar cell includes a substrate 1, the substrate 1 includes a bottom cell 11, an electron-hole recombination layer 12 disposed on the bottom cell 11, and the perovskite solar cell further includes a first transport layer 2, a perovskite layer 3, a second transport layer 4, and a transparent conductive layer 5 disposed on the electron-hole recombination layer 12 in sequence, and the perovskite solar cell further includes an electrode 6, the electrode 6 includes a first electrode 61 and a second electrode 62, the first electrode 61 is disposed on a side of the transparent conductive layer 5 away from the second transport layer 4, and the second electrode 62 is disposed on a side of the bottom cell 11 away from the electron-hole recombination layer 12; wherein one of the first electrode 61 and the second electrode 62 is a positive electrode, and the other is a negative electrode, one of the first transport layer 2 and the second transport layer 4 is a hole transport layer, and the other is an electron transport layer.

[0102] Optionally, when the first transport layer 2 is a hole transport layer and the second transport layer 4 is an electron transport layer, the perovskite layer 3 is located above the self-assembled molecular layer 7, and the electron transport layer is located above the perovskite layer 3.

[0103] The material of the electron-hole recombination layer 12 includes at least one of indium zinc oxide and indium tin oxide. The thickness of the electron transport layer is 15 nm to 20 nm. The material of the transparent conductive layer 5 includes at least one of indium zinc oxide, indium tin oxide, and indium tin oxide, and the thickness of the transparent conductive layer 5 is 80 nm to 120 nm. The first electrode 61 and / or the second electrode 62 includes at least one of silver, gold, copper, and aluminum, the thickness of the first electrode 61 is 150 nm to 300 nm, and the thickness of the second electrode 62 is 100 nm to 120 nm.

[0104] ​Further, the perovskite solar cell further comprises a passivation layer 8 arranged between the perovskite layer 3 and the second transport layer 4, the material of the passivation layer 8 comprises lithium fluoride. The passivation layer 8 can passivate the interface defects of the perovskite layer 3, improve the compatibility of the perovskite layer 3 and the second transport layer 4, reduce the interface defects, and reduce the interface recombination, thereby improving the extraction of the carriers by the second transport layer 4 and improving the migration ability of the carriers.

[0105] In addition, the perovskite solar cell further comprises a buffer layer arranged between the second transport layer 4 and the transparent conductive layer 5, the material of the buffer layer 9 comprises tin dioxide, and the thickness of the buffer layer 9 is 20 nm to 30 nm. The buffer layer 9 can play a blocking role to avoid damage to the second transport layer 4 and the perovskite layer 3 during preparation of the transparent conductive layer 5, thereby helping to improve the performance of the perovskite solar cell.

[0106] In addition, the perovskite solar cell further comprises an anti-reflection layer 10 arranged on the transparent conductive layer 5, the material of the anti-reflection layer 10 is at least one of magnesium fluoride and lithium fluoride, and the thickness of the anti-reflection layer 10 is 100 nm to 120 nm. By arranging the anti-reflection layer 10 and adjusting the thickness thereof, the utilization rate of sunlight can be effectively improved, and the performance of the perovskite solar cell can be improved.

[0107] In another alternative embodiment, the perovskite solar cell can be a single-junction cell. The perovskite solar cell is further described below.

[0108] The perovskite solar cell comprises a substrate, the substrate is a transparent conductive substrate, and the perovskite solar cell further comprises a first transport layer, a second transport layer, a first electrode, and a second electrode. The first transport layer is arranged on the transparent conductive substrate, the perovskite layer is arranged between the first transport layer and the second transport layer, the second transport layer is arranged on the side of the perovskite layer away from the first transport layer, the first electrode is arranged on the side of the second transport layer away from the perovskite layer, and the second electrode is arranged on the side of the transparent conductive substrate away from the first transport layer. One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. One of the first transport layer and the second transport layer is a hole transport layer, and the other is an electron transport layer.

[0109] In a second aspect, the embodiments of the present application disclose a preparation method of a perovskite solar cell, and the preparation method comprises the following steps:

[0110] An self-assembled monolayer is prepared between the hole transport layer and the perovskite layer. The material of the self-assembled monolayer comprises a polymer formed by polymerization of a donor material and an acceptor material.

[0111] Post-processing is performed to obtain the perovskite solar cell of the first aspect.

[0112] Further, the preparation method comprises the following steps:

[0113] preparing a self-assembled monolayer on the hole transport layer: coating a solution containing a polymer on the hole transport layer;

[0114] annealing to obtain the self-assembled monolayer;

[0115] preparing a perovskite layer on the self-assembled monolayer.

[0116] In the coating process, the mass concentration of the polymer is controlled to be 0.8 mg / mL-1.2 mg / mL, so that the polymer has high solubility and dispersibility in the solution, thereby making the self-assembled monolayer prepared have good dispersibility, high compactness and high linearity. In addition, in this step, the solvent in the solution includes a first solvent and a second solvent, the volume ratio of the first solvent to the second solvent is 0.5:1-1:1, the first solvent includes at least one of trichloromethane and chloroform, and the second solvent is ethanol; wherein the presence of the first solvent makes the polymer have high solubility, and by controlling the mass ratio of the two, the solubility and dispersibility of the polymer in the solution are high, so that the compactness and linearity of the film layer prepared finally are high.

[0117] In addition, in the annealing step, the annealing temperature is 90℃-110℃, and the time is 5 min-15 min. By controlling the annealing parameters, the film layer prepared has high quality.

[0118] Further, before the step of preparing the self-assembled monolayer on the hole transport layer, the preparation method further includes preparing the polymer, and the step of preparing the polymer includes:

[0119] reacting a mixed solution containing an electron-donating material, an electron-withdrawing material and a catalyst to obtain a polymer precursor;

[0120] dispersing and filtering the polymer precursor in a solvent to obtain the polymer.

[0121] In the step of preparing the polymer, the catalysts are tris(dibenzylideneacetone)dipalladium (Pd2(dba)3) and tri(o-tolyl)phosphine (P(o-toly)3), and the molar ratio of tris(dibenzylideneacetone)dipalladium to tri(o-tolyl)phosphine is 1:3-1:5. By controlling the molar ratio of the two catalysts, the reaction completeness can be improved, and the molecular weight of the polymer prepared is suitable. In this step, the mixed solution is reacted at a temperature of 100-120℃ for 45-50h in the dark. By controlling the reaction conditions, the reaction completeness can be further improved, and the yield of the polymer prepared is high and the molecular weight is suitable.

[0122] In addition, the step of preparing the polymer comprises:

[0123] dispersing the polymer precursor in a dispersion liquid to form an extraction liquid;

[0124] The extraction liquid is subjected to Soxhlet extraction and silica gel column filtration to remove impurities and oligomers in the extraction liquid, and the polymer is prepared after precipitation, concentration and filtration.

[0125] In the step of forming the extraction liquid, the polymer precursor is dispersed in 100-300mL of a dispersion liquid to form the extraction liquid, wherein the dispersion liquid comprises methanol.

[0126] In the step of preparing the polymer, the extraction liquid is subjected to Soxhlet extraction with methanol, n-hexane and acetone to remove part of the impurities and oligomers. After the Soxhlet extraction is completed, the extraction liquid is subjected to secondary extraction with chloroform. This is because chloroform has a high solubility and can dissolve the target substance (i.e. the polymer) to further separate it from the poorly soluble substances. The chloroform containing the target substance is concentrated and subjected to silica gel column filtration to extract the target product by utilizing the porous structure of the silica gel column. The filtrate obtained by the silica gel column filtration is concentrated and dispersed to obtain a polymer with high purity and better quality.

[0127] In addition, the Soxhlet extraction of the extraction liquid with methanol, n-hexane and acetone means that the extraction liquid is extracted with methanol, n-hexane and acetone respectively in several times. Methanol can dissolve impurities with strong polarity and remove substances such as salts and small molecules with strong polarity. N-hexane can dissolve non-polar impurities and remove substances such as oils and hydroxyls. Acetone can assist methanol in dissolving part of the residual polar impurities and cooperate with n-hexane to remove part of the non-polar impurities. Therefore, by extracting with the three solvents, part of the impurities and oligomers can be removed, and the purity of the polymer can be improved.

[0128] Further, the step of preparing the perovskite layer on the self-assembled monolayer comprises: preparing a lead framework layer on the self-assembled monolayer by co-evaporation; spin-coating a cation solution on the lead framework layer to obtain the perovskite layer through annealing.

[0129] Further, the evaporation source material of the lead framework layer comprises PbX and CsX, and the evaporation rate is The CsX can improve the porosity and looseness of the structure of the lead framework layer, so that the prepared lead framework layer has a suitable pore structure, which is conducive to the reaction of the cation solution with the lead framework layer. The X ion in PbX and CsX includes at least one of I ion, Br ion and Cl ion. Specifically, the CsX includes at least one of CsI and CsCl; and the PbX includes at least one of PbBr2 and PbCl2. In addition, the thickness of the lead framework layer prepared by the present application is 300 nm to 400 nm. When the thickness of the lead framework layer is within the above range, the thickness of the perovskite layer prepared finally is suitable, thereby improving the performance of the perovskite solar cell.

[0130] Specifically, the lead framework layer can be prepared by a process of double-source co-evaporation, wherein the evaporation rate of PbX and CsX is 5:1 to 10:1. By controlling the evaporation rate ratio of the two, the lead framework layer has a suitable pore structure, so that the cation solution can enter the inside of the framework layer and react with it, thereby improving the crystalline quality of the perovskite layer.

[0131] In addition, in the step of spin-coating the cation solution on the lead framework layer, the cation solution includes at least two of FAI, FABr, MABr and MACl; the molar concentration of the FAI is 0.3 mol / L to 0.6 mol / L; and / or the molar concentration of the FABr is 0 mol / L to 0.2 mol / L; and / or the molar concentration of the MABr is 0 mol / L to 0.2 mol / L; and / or the molar concentration of the MACl is 0.05 mol / L to 0.25 mol / L.

[0132] By controlling the types and concentrations of the cation solution within the above range, the reactivity of the cation solution with the lead framework layer is ensured, thereby improving the crystalline quality of the perovskite layer to a high degree, reducing the interface defects between the perovskite layer and the self-assembled monolayer, and improving the stability of the interface. In addition, when the perovskite layer is located on the self-assembled monolayer, the self-assembled monolayer can further promote the crystalline growth process of the perovskite layer, thereby ensuring that the prepared perovskite layer has high crystalline quality.

[0133] In addition, by controlling the annealing time to be 15-30 min and the annealing temperature to be 100-170℃, the quality of the perovskite layer crystals is higher and the defects are fewer.

[0134] In the preparation process, the perovskite layer is prepared by a two-step method, in which a lead framework layer is first prepared and then a cation solution is spin-coated, the cation solution penetrates the lead framework layer to react and convert the lead framework layer into a perovskite phase, so that the perovskite layer prepared has a high coverage on the self-assembled monolayer and a complete morphology, and can be consistent with the structure of the self-assembled monolayer. If the self-assembled monolayer has a texture structure, the perovskite layer prepared has a texture structure, so that the light trapping property of the texture structure can be utilized to improve the short-circuit current density of the solar cell, thereby improving the photoelectric conversion rate of the perovskite solar cell.

[0135] In a third aspect, the embodiments of the present application disclose a photovoltaic module, comprising the perovskite solar cell of the first aspect, or the perovskite solar cell prepared by the preparation method of the second aspect.

[0136] The technical solutions of the present application will be further explained below in combination with more specific embodiments and experimental test results.

[0137] Embodiment one:

[0138] The embodiments of the present application provide a solar cell, which is a laminated solar cell. The preparation method of the solar cell comprises the following steps:

[0139] An HJT crystalline silicon bottom cell is provided, and a 20-nm-thick indium tin oxide electron-hole recombination layer is prepared on the light-receiving surface of the bottom cell by magnetron sputtering.

[0140] A 20-nm-thick nickel oxide hole transport layer is deposited on the electron-hole recombination layer by physical vapor deposition.

[0141] Preparation of the polymer:

[0142] Before the polymer is prepared, 0.12 mmol of DTP and 0.12 mmol of TPD-Sn are dissolved in degassed toluene, 5.1 μmol of Pd2(dba)3 and 20.4 μmol of P(o-toly)3 are added to form a mixed solution, and the mixed solution is reacted at 110℃ in the dark for 48 h to obtain a polymer precursor.

[0143] The polymer precursor is dispersed in 200 mL of methanol to form an extraction solution; the extraction solution is subjected to Soxhlet extraction with methanol, n-hexane and acetone, and then subjected to extraction with chloroform, and the extracted solution is concentrated and filtered through a silica gel column, and the obtained filtrate is concentrated and filtered to obtain the polymer PDTP-TPD. Figure 2as shown, Figure 2 The synthesis route of PDTP-TPD is provided for the embodiment of the present application.

[0144] Preparation of the self-assembled monolayer on the nickel oxide hole transport layer:

[0145] The solution containing the polymer is coated on the hole transport layer, the concentration of the polymer in the solution is 1.0 mg / mL, and the volume ratio of trichloromethane to ethanol in the solvent is 0.8:1;

[0146] Annealing at 100 ℃ for 10 minutes to obtain the self-assembled monolayer, the molecular weight of the self-assembled monolayer is 3.5 W, the energy level difference between the hole transport layer and the self-assembled monolayer is 0.5 eV, the energy level difference between the self-assembled monolayer and the perovskite layer is 0.2 eV, the longest side length of the bottom of the pinnate structure of the self-assembled monolayer is 1 μm-3 μm, and the height of the pinnate structure is 1 μm-3 μm.

[0147] Formation of the perovskite layer on the self-assembled monolayer:

[0148] Double-source co-evaporation is performed on the hole transport layer to form a lead skeleton layer with a thickness of 350 nm, wherein the evaporation rate ratio of PbI2 and CsCl is 8:1;

[0149] 0.4 mol / L of FAI, 0.1 mol / L of FABr, 0.1 mol / L of MABr, and 0.15 mol / L of MACl are mixed and dissolved in ethanol to obtain a cation solution, which is coated on the lead skeleton layer by using a doctor blade coating method, the spin coating speed is 4500 rpm, and the time is 30 s; then annealing at 150 ℃ for 20 min to obtain a perovskite layer with a thickness of 500 nm.

[0150] Evaporation of a 1 nm thick lithium fluoride passivation layer on the perovskite layer, the evaporation rate is

[0151] Evaporation of a 15 nm thick C60 electron transport layer on the lithium fluoride passivation layer, the evaporation rate is

[0152] Preparation of a 20 nm thick tin dioxide buffer layer on the electron transport layer by using atomic layer deposition.

[0153] Preparation of a layer of indium zinc oxide transparent conductive layer with a thickness of about 90 nm on the buffer layer by magnetron sputtering.

[0154] Vacuum evaporation of a 200 nm thick silver first electrode on the transparent conductive layer, and vacuum evaporation of a 100 nm thick silver second electrode on the back light surface of the bottom cell, wherein the first electrode is the positive electrode, and the second electrode is the negative electrode.

[0155] A lithium fluoride antireflection layer with a thickness of approximately 110 nm was deposited on the first electrode by evaporation at a rate of [missing information]. The refractive index is 1.4.

[0156] Structural testing:

[0157] like Figure 3 As shown, Figure 3 The molecular configuration diagram of the polymer provided in Embodiment 1 of this application is obtained by DFT simulation calculation. As can be seen from the figure, the polymer has high linearity and no high steric hindrance. It has a high interface matching degree with the hole transport layer and the perovskite layer, and helps to promote the crystal growth process of the perovskite layer, ensuring that the prepared perovskite layer has high crystal quality.

[0158] Example 2:

[0159] The only difference between this embodiment and Embodiment 1 is that the molar ratio of electron-donating material to electron-withdrawing material in this embodiment is 1:1.2.

[0160] Example 3:

[0161] The only difference between this embodiment and Embodiment 1 is that the molar ratio of electron-donating material to electron-withdrawing material in this embodiment is 1:1.1.

[0162] Example 4:

[0163] The only difference between this embodiment and Embodiment 1 is that the molar ratio of electron-donating material to electron-withdrawing material in the polymer of this embodiment is 0.9:1. 。

[0164] Example 5:

[0165] The only difference between this embodiment and Embodiment 1 is that the molar ratio of electron-donating material to electron-withdrawing material in the polymer of this embodiment is 1:1.3.

[0166] Example 6:

[0167] The only difference between this embodiment and Embodiment 1 is that the molecular weight of the polymer in this embodiment is 4W.

[0168] Example 7:

[0169] The only difference between this embodiment and Embodiment 1 is that the molecular weight of the polymer in this embodiment is 3W.

[0170] Example 8:

[0171] The only difference between this embodiment and Embodiment 1 is that the molecular weight of the polymer in this embodiment is 4.5W.

[0172] Example 9:

[0173] The difference between this embodiment and embodiment one is that the molecular weight of the polymer in this embodiment is 2.5W.

[0174] Embodiment ten:

[0175] The difference between this embodiment and embodiment one is that the electron-withdrawing material in this embodiment is The electron-donating material is

[0176] Embodiment eleven:

[0177] The difference between this embodiment and embodiment one is that in the step of preparing the self-assembled monolayer, the concentration of the polymer is 1.6mg / mL.

[0178] Embodiment twelve:

[0179] The difference between this embodiment and embodiment one is that in the step of preparing the self-assembled monolayer, the volume ratio of chloroform to ethanol is 0.2:1.

[0180] Embodiment thirteen:

[0181] The preparation method of the single-junction solar cell provided by this embodiment comprises:

[0182] A transparent conductive substrate is provided.

[0183] A 20nm-thick nickel oxide hole transport layer is deposited on the electron-hole recombination layer by physical vapor deposition.

[0184] A polymer is prepared:

[0185] Before the polymer is prepared, 0.12mmol of DTP and 0.12mmol of TPD-Sn are dissolved in degassed toluene, and 5.1μmol of Pd2(dba)3 and 20.4μmol of P(o-toly)3 are added to form a mixed solution, and the mixed solution is reacted at 110℃ in the dark for 48h to obtain a polymer precursor.

[0186] The polymer precursor is dispersed in 200mL of methanol to form an extraction solution; the extraction solution is subjected to Soxhlet extraction with methanol, n-hexane and acetone, and then subjected to extraction with chloroform, and the extracted solution is concentrated and filtered through a silica gel column, and the obtained filtrate is concentrated and filtered to obtain the polymer PDTP-TPD.

[0187] A self-assembled monolayer is prepared on the nickel oxide hole transport layer:

[0188] A solution containing the polymer is coated on the hole transport layer, the concentration of the polymer in the solution is 1.0mg / mL, and the volume ratio of chloroform to ethanol in the solvent is 0.8:1.

[0189] The self-assembled monolayer is prepared by annealing at 100℃ for 10 minutes, the molecular weight of the self-assembled monolayer is 3.5W, the energy level difference between the hole transport layer and the self-assembled monolayer is 0.5eV, the energy level difference between the self-assembled monolayer and the perovskite layer is 0.2eV, the longest side length of the tower bottom of the corrugated structure of the self-assembled monolayer is 1μm-3μm, and the height of the corrugated structure is 1μm-3μm.

[0190] The perovskite layer is formed on the self-assembled monolayer:

[0191] The lead framework layer with a thickness of 350nm is prepared by double-source co-evaporation on the hole transport layer, wherein the evaporation rate ratio of PbI2 and CsCl is 8:1.

[0192] The cation solution is obtained by mixing 0.4mol / L of FAI, 0.1mol / L of FABr, 0.1mol / L of MABr and 0.15mol / L of MACl in ethanol, and then the solution is coated on the lead framework layer by using the doctor blade coating method, the spin coating speed is 4500rpm, and the time is 30s; then the perovskite layer with a thickness of 500nm is obtained by annealing at 150℃ for 20min.

[0193] The 15nm-thick C60 electron transport layer is evaporated on the perovskite layer, and the evaporation rate is

[0194] The 200nm-thick silver first electrode is prepared by vacuum evaporation on the electron transport layer, and the 100nm-thick silver second electrode is prepared by vacuum evaporation on the transparent conductive substrate, wherein the first electrode is the positive electrode, and the second electrode is the negative electrode.

[0195] Comparative Example One:

[0196] The difference between this comparative example and Example One is that the material of the self-assembled monolayer in this example is 2PACZ.

[0197] Comparative Example Two:

[0198] The difference between this comparative example and Example One is that the self-assembled monolayer is not arranged between the hole transport layer and the perovskite layer of the perovskite solar cell in this example.

[0199] Test Data One:

[0200] The solar cells prepared in Examples One to Thirteen and Comparative Examples One to Two are tested as follows:

[0201] The application provides a solar cell, which is tested in terms of open circuit voltage, short circuit current and fill factor by using a halm test sorting device. The halm machine is a device for simulating sunlight, and is further provided with an electronic load, a data acquisition and calculation device and the like, and is used for testing the electrical performance of a photovoltaic device (including a solar cell, such as Eta, Voc, Jsc, FF and the like, which are used for reflecting the performance of the solar cell). The silicon wafer of the solar cell controlled in the test is 1.07 cm 2 The calibrated light intensity is 1000±50 W / m2, and the experimental test results are as follows, in which Voc represents open circuit voltage, Jsc represents short circuit current density, FF represents fill factor, and Eta represents photoelectric conversion efficiency. The experimental test results are shown in Table 1.

[0202] Table 1: Performance test results of the solar cell

[0203]

[0204]

[0205] It can be known from the data of Examples 1 to 13 and Comparative Examples 1 and 2 that the photoelectric conversion rate of the examples is better than that of Comparative Examples 1 and 2, because the self-assembled monolayer in the examples contains a polymer formed by polymerization of the electron-donating material and the electron-accepting material, so that the push-pull effect of the electron-donating material and the electron-accepting material can be effectively utilized to form a channel in the self-assembled monolayer which is beneficial to the transmission of holes, thereby improving the transmission capacity of the holes; and the material of the self-assembled monolayer in Comparative Example 1 is 2PACZ, which has a high aggregation degree, poor dispersibility and poor matching with the hole transport layer and the perovskite layer, so that the transmission of carriers is blocked.

[0206] It can be known from the data of Examples 1 to 5 that the photoelectric conversion rate of Examples 1 to 3 is better than that of Examples 4 and 5, because the molar ratio of the electron-donating material to the electron-accepting material in Examples 1 to 3 is in the range of 1:1 to 1:1.2, which is conducive to the formation of a dipole moment in the self-organizing monolayer, so that the linearity of the self-organizing monolayer is high, the film layer is dense, and the matching degree between the self-organizing monolayer and the perovskite layer and the hole transport layer is high, thereby effectively improving the photoelectric conversion rate of the solar cell.

[0207] As can be seen from the data of Example 1, Example 6 to Example 9, the photoelectric conversion rate of Example 1, Example 6 and Example 7 is higher than that of Example 8, because the molecular weight of the polymer in Example 1, Example 6 and Example 7 is lower, and the solubility of the polymer is higher, so the linearity of the self-organizing monolayer formed by Example 1, Example 6 and Example 7 is higher, thereby helping to improve the photoelectric conversion efficiency of the solar cell; the photoelectric conversion rate of Example 1, Example 6 and Example 7 is higher than that of Example 9, because the molecular weight of the polymer in Example 1, Example 6 and Example 7 is higher, so the order of the molecular packing structure formed by Example 1, Example 6 and Example 7 is higher, and the intermolecular force is stronger, so it not only helps to improve the transmission efficiency of the hole to a higher degree, but also promotes the formation of a more stable chemical and physical combination between the self-assembled monolayer and the hole transport layer and the perovskite layer, thereby further improving the photoelectric conversion rate of the solar cell.

[0208] As can be seen from the data of Example 1 and Example 10, the photoelectric conversion rate of Example 1 is higher than that of Example 10, because the electron-donating material and the electron-accepting material in Example 1 both have carbonyl groups, which can effectively passivate the cation defects in the perovskite layer, thereby helping to further improve the photoelectric conversion rate of the perovskite solar cell.

[0209] As can be seen from the data of Example 1 and Example 11, the photoelectric conversion rate of Example 1 is higher than that of Example 11, because the concentration of the polymer in Example 1 is in the range of 0.8 mg / mL to 1.2 mg / mL, so the solubility and dispersibility of the polymer in Example 1 in the solution is higher than that of Example 11, thereby making the self-assembled monolayer prepared have good dispersibility, high density and high linearity, which helps to further improve the photoelectric conversion efficiency of the solar cell.

[0210] As can be seen from the data of Example 1 and Example 12, the photoelectric conversion rate of Example 1 is higher than that of Example 12, because the volume ratio of chloroform to ethanol in Example 1 is in the range of 0.5:1 to 1:1, and the control of the mass ratio of the two further improves the solubility and dispersibility of the polymer in the solution, so that the density of the finally prepared film layer is higher and the linearity is higher.

[0211] As can be seen from the data of Example 1 and Example 13, the photoelectric conversion rate of Example 1 is higher than that of Example 13, because the solar cell of Example 1 is a stacked solar cell, so it can absorb different wavelengths of sunlight, thereby improving the utilization rate of sunlight to a higher degree, thereby further improving the photoelectric conversion efficiency of the solar cell.

[0212] The perovskite solar cell and the preparation method thereof and the photovoltaic module disclosed in the above embodiments of the application are described in detail, and the principles and implementation manners of the application are described by applying specific examples; the above embodiment descriptions are only used to help understand the perovskite solar cell and the preparation method thereof and the photovoltaic module; meanwhile, for those skilled in the art, according to the idea of the application, the specific implementation manners and application ranges will be changed, and on the basis of the above, the content of the specification should not be understood as a limitation on the application.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell includes: a hole transport layer, a perovskite layer, and a self-assembled monolayer located between the hole transport layer and the perovskite layer; The self-assembled monolayer is made of a polymer formed by polymerizing electron-donating and electron-withdrawing materials.

2. The perovskite solar cell according to claim 1, characterized in that, The molar ratio of the electron-donating material to the electron-withdrawing material is 1:1 to 1:1.

2.

3. The perovskite solar cell according to claim 1, characterized in that, The polymer has a molecular weight of 3W to 4W.

4. The perovskite solar cell according to claim 1, characterized in that, The active groups of the polymer include at least one of Lewis acids, Lewis bases, carbonyl groups, and amino groups.

5. The perovskite solar cell according to claim 1, characterized in that, The electron-absorbing material includes at least one of the following: Wherein, R0, R1, R2, and R3 are all first alkyl groups, and the first alkyl group includes -CH3, -C2H5, -C3H7, -C4H9, and -C5H. 11 -C6H 13 -C7H 15 -C8H 17 -C9H 19 or -C 10 H 21 ; The electron-donating material includes at least one of the following: Among them, R4, R5, R6, R7, and R8 are all second alkyl groups, and the second alkyl group includes -CH3, -C2H5, -C3H7, -C4H9, and -C5H. 11 -C6H 13 -C7H 15 -C8H 17 -C9H 19 or -C 10 H 21 .

6. The perovskite solar cell according to claim 1, characterized in that, The energy level difference between the self-assembled monolayer and the perovskite layer is 0.1 eV to 0.3 eV; and / or, The energy level difference between the hole transport layer and the self-assembled monolayer is 0.4 eV to 0.6 eV.

7. The perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell also includes a substrate, with the self-assembled monolayer disposed close to the substrate, and the perovskite layer located on the side of the self-assembled monolayer facing away from the substrate.

8. The perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell further includes a substrate having a pyramid structure. The textured structure of the self-assembled monolayer is consistent with the pyramid structure of the substrate. The longest side length of the base of the textured structure of the self-assembled monolayer is 1 μm to 3 μm, and the height of the textured structure of the self-assembled monolayer is 1 μm to 3 μm.

9. The perovskite solar cell according to claim 1, characterized in that, The hole transport layer is made of at least one of nickel oxide, molybdenum oxide, and vanadium oxide; and / or, The thickness of the hole transport layer is 20nm to 30nm; and / or, The thickness of the perovskite layer is 450 nm to 550 nm; and / or, The electron-donating material includes dithienopyrroledione, and the electron-withdrawing material includes thienopyrroledione.

10. The perovskite solar cell according to any one of claims 1 to 9, characterized in that, The perovskite solar cell is a tandem solar cell. The perovskite solar cell includes a substrate, a bottom cell, and an electron-hole recombination layer disposed on the bottom cell. The perovskite solar cell also includes a first transport layer, a second transport layer, a transparent conductive layer, and electrodes. The first transport layer is disposed on the side of the electron-hole recombination layer opposite to the bottom cell. The perovskite layer is disposed between the first and second transport layers. The second transport layer is disposed on the side of the perovskite layer opposite to the first transport layer. The transparent conductive layer is disposed on the side of the second transport layer opposite to the perovskite layer. The electrodes include a first electrode and a second electrode. The first electrode is disposed on the side of the transparent conductive layer opposite to the second transport layer, and the second electrode is disposed on the side of the bottom cell opposite to the electron-hole recombination layer. Specifically, one of the first and second electrodes is a positive electrode, and the other is a negative electrode. One of the first and second transport layers is a hole transport layer, and the other is an electron transport layer. Alternatively, the perovskite solar cell is a single-junction cell. The perovskite solar cell includes a substrate, which is a transparent conductive substrate. The perovskite solar cell further includes a first transport layer, a second transport layer, a first electrode, and a second electrode. The first transport layer is disposed on the transparent conductive substrate. The perovskite layer is disposed between the first transport layer and the second transport layer. The second transport layer is disposed on the side of the perovskite layer opposite to the first transport layer. The first electrode is disposed on the side of the second transport layer opposite to the perovskite layer, and the second electrode is disposed on the side of the transparent conductive substrate opposite to the first transport layer. Wherein, one of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode. One of the first transport layer and the second transport layer is a hole transport layer, and the other is an electron transport layer.

11. A method for preparing a perovskite solar cell, characterized in that, The preparation method includes the following steps: A self-assembled monolayer is prepared between a hole transport layer and a perovskite layer; wherein the material of the self-assembled monolayer includes a polymer formed by polymerizing electron-donating and electron-withdrawing materials; Post-processing yields the perovskite solar cell as described in any one of claims 1 to 10.

12. The preparation method according to claim 11, characterized in that, The preparation method includes the following steps: Prepare the self-assembled monolayer on the hole transport layer: coat the hole transport layer with a solution containing the polymer; Annealing was performed to obtain the self-assembled monolayer. The perovskite layer is prepared on the self-assembled monolayer.

13. The preparation method according to claim 12, characterized in that, The polymer has a mass concentration of 0.8 mg / mL to 1.2 mg / mL.

14. The preparation method according to claim 12, characterized in that, The solvent in the solution includes a first solvent and a second solvent, wherein the volume ratio of the first solvent to the second solvent is 0.5:1 to 1:1, the first solvent includes at least one of chloroform and trichloromethane, and the second solvent is ethanol; and / or, In the annealing step, the annealing temperature is 90℃~110℃ and the time is 5min~15min.

15. The preparation method according to claim 11, characterized in that, Prior to the step of preparing a self-assembled monolayer on the hole transport layer, the preparation method further includes preparing the polymer, the step of preparing the polymer including: A polymer precursor is prepared by reacting a mixed solution containing the electron-donating material, the electron-withdrawing material, and the catalyst. The polymer precursor is dispersed in a solvent and filtered to obtain the polymer.

16. The preparation method according to claim 15, characterized in that, In the step of preparing the polymer precursor, the catalyst is tris(dibenzylacetone)dipalladium and tris(o-tolyl)phosphine, and the molar ratio of tris(dibenzylacetone)dipalladium to tris(o-tolyl)phosphine is 1:3 to 1:5; and / or, In the step of preparing the polymer precursor, the mixed solution is reacted at a temperature of 100°C to 120°C in the dark for 45 to 50 hours; and / or, The step of obtaining the polymer includes: The polymer precursor is dispersed in a dispersion to form an extract; The extract was subjected to Soxhlet extraction and silica gel column filtration to remove impurities and oligomers. The polymer was then obtained after precipitation, concentration, and filtration.

17. The preparation method according to any one of claims 11 to 16, characterized in that, The step of preparing the perovskite layer on the self-assembled monolayer includes: A lead framework layer was prepared on the self-assembled monolayer by co-evaporation. The cationic solution was spin-coated onto the lead framework layer and then annealed to obtain the perovskite layer.

18. The preparation method according to claim 17, characterized in that, In the step of preparing the lead framework layer on the self-assembled monolayer by co-evaporation, the evaporation source materials of the lead framework layer include PbX and CsX, and the evaporation rate is... The X ions in the PbX and CsX include at least one of I ions, Br ions, and Cl ions; and / or... In the step of spin-coating the cationic solution onto the lead framework layer, the cationic solution includes at least two of FAI, FABr, MABr, and MACl. Wherein, the molar concentration of the FAI is 0.3 mol / L to 0.6 mol / L; and / or, The molar concentration of FABr is 0 mol / L to 0.2 mol / L; and / or, The molar concentration of the MABr is 0 mol / L to 0.2 mol / L; and / or, The molar concentration of MACl is 0.05 mol / L to 0.25 mol / L.

19. A photovoltaic module, characterized in that, include: The perovskite solar cell according to any one of claims 1 to 10, or the perovskite solar cell prepared by the preparation method according to any one of claims 11 to 18.

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