Application of Compound in Solar Cell, Solar Cell and Preparation Method Thereof

Abstract

Embodiments of the present invention provide an application of a compound in a solar cell, a solar cell and a preparation method thereof. The compound is formed by an organic small molecule or a polymer, and the chemical structural formula of the repeating unit of the organic small molecule and the polymer is F1-R-F2, where R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, and the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group. When the above compound is used to prepare a modified layer and used in a solar cell, carrier recombination can be weakened, the efficiency of the solar cell can be effectively improved, and a hole transport layer specifically used for transporting holes can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly to an application of a modification layer in a solar cell, a solar cell and a preparation method thereof. Background Art

[0002] In recent years, the technology of solar cells has become increasingly mature. Among them, hybrid perovskite solar cells, as a new type of solar cell with high efficiency and low cost, have attracted extensive attention.

[0003] Currently, a silicon / perovskite tandem solar cell generally includes: a silicon substrate cell / a tunneling junction or a transparent conductive layer / a first carrier transport layer / a wide-bandgap perovskite layer / a second carrier transport layer / a top electrode.

[0004] However, the interfacial defects at the lower interface of the wide-bandgap perovskite layer are likely to cause relatively serious carrier recombination, which greatly affects the improvement of the efficiency of hybrid perovskite solar cells. Summary of the Invention

[0005] In view of the above problems, embodiments of the present invention are proposed to provide an application of a modification layer in a solar cell, a solar cell and a preparation method thereof that can overcome the above problems or at least partially solve the above problems.

[0006] To solve the above problems, in a first aspect, embodiments of the present invention disclose an application of a compound in a solar cell. The compound is formed by an organic small molecule or a polymer. The chemical structural formula of the repeating unit of the organic small molecule and the polymer is F1-R-F2, where R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, and the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group.

[0007] Optionally, the nitrogen-containing group is selected from at least one of an amino group, a quaternary ammonium salt, an amidino group, an amide group, and an imide group; the sulfur-containing group is selected from at least one of a thiol group, a thioether group, a sulfinyl group, a sulfonyl group, and a sulfonic acid group; the oxygen-containing group is selected from at least one of a hydroxyl group, an ether oxygen group, a siloxanyl group, a carboxyl group, an acid anhydride group, an ester group, an aldehyde group, a ketone group, and an acyl halide group; and the phosphorus-containing group is selected from at least one of a phosphoric acid group, a phosphoric acid ester group, and a phosphino group.

[0008] Optionally, the modification layer prepared from the compound can be used in a solar cell, and the modification layer is laminated between a perovskite absorption layer and a composite layer.

[0009] Second aspect, embodiments of the present invention also disclose a solar cell, comprising: a first electrode, a substrate cell, a composite layer, a modification layer, a light absorption layer, an electron transport layer, and a second electrode, which are sequentially stacked, wherein,

[0010] An interface of the light absorption layer close to the modification layer is a first interface, and an interface of the composite layer close to the modification layer is a second interface;

[0011] The modification layer can interact with the light absorption layer to passivate defects at the first interface; the modification layer can interact with the composite layer to modify the second interface;

[0012] The modification layer is prepared from the above-mentioned compound.

[0013] Optionally, the light absorption layer is a perovskite layer formed by hybridization of inorganic materials or organic materials and inorganic materials, and the composite layer is an inorganic layer formed by inorganic materials.

[0014] Optionally, the functional group F1 interacts with the composite layer by at least one of chemical bond, coordination bond, dipole interaction, and van der Waals force.

[0015] Optionally, the functional group F2 interacts with the light absorption layer by at least one of chemical bond, hydrogen bond, coordination bond, dipole interaction, and van der Waals force.

[0016] Optionally, the thickness of the modification layer is 0.1 - 10 nanometers.

[0017] Optionally, the composite layer includes at least one of a tunneling junction and a transparent conductive layer.

[0018] Third aspect, embodiments of the present invention also disclose a preparation method of a solar cell, comprising:

[0019] Providing a substrate cell;

[0020] Preparing a composite layer on one side surface of the substrate cell;

[0021] Using the above-mentioned compound to prepare a modification layer on a side surface of the composite layer facing away from the substrate cell;

[0022] Preparing a light absorption layer on a side surface of the modification layer facing away from the composite layer;

[0023] Preparing an electron transport layer on a side surface of the light absorption layer facing away from the modification layer;

[0024] Preparing a second electrode on a side surface of the electron transport layer facing away from the modification layer;

[0025] A first electrode is prepared on a surface of the base cell facing away from the composite layer.

[0026] Optionally, the modification layer can be prepared on the composite layer by at least one of spin coating, dipping, fumigation, scraping, slot coating, spraying, printing, vacuum deposition, and film drawing.

[0027] Embodiments of the present invention include the following advantages:

[0028] In an embodiment of the present invention, the compound may include a unit with a chemical structural formula of F1-R-F2. When the compound is applied to prepare a solar cell, the modification layer can be prepared between the composite layer and the light absorption layer using the compound. Since the functional group F1 includes at least one of a silicon-containing group, a phosphate group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, the modification layer can interact with the composite layer, modify the composite layer, and adjust the energy level of the composite layer, making the energy level of the composite layer more matched with the energy level of the light absorption layer, which is beneficial for the transmission and collection of holes, and can avoid setting a hole transport layer specifically for hole transport; since the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group, the modification layer can interact with the light absorption layer, passivate the defects of the light absorption layer, weaken the carrier recombination, and effectively improve the efficiency of the solar cell. Description of the Drawings

[0029] Figure 1 is a schematic structural diagram of a solar cell of the present invention;

[0030] Figure 2 is a flowchart of a preparation method of a solar cell of the present invention;

[0031] Figure 3 is the I-V curve of the solar cells of Example 1 and Comparative Example 1 of the present invention;

[0032] Figure 4 is the I-V curve of the solar cells of Example 2 and Comparative Example 1 of the present invention;

[0033] Figure 5 is the I-V curve of the solar cells of Example 3 and Comparative Example 2 of the present invention.

[0034] Reference Signs:

[0035] 1 - First electrode, 2 - Base cell, 3 - Composite layer, 4 - Modification layer, 5 - Light absorption layer, 6 - Electron transport layer, 7 - Transparent conductive film, 8 - Second electrode. Detailed Embodiments

[0036] To make the above objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "thickness", "upper", "lower", etc. are based on the orientation or positional relationships shown in the accompanying drawings. These are only for facilitating the description of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0038] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] One of the core concepts of the embodiments of the present invention is to disclose the application of a compound in a solar cell. The compound can be formed by an organic small molecule or a polymer. The chemical structural formula of the repeating unit of the organic small molecule and the polymer can be F1-R-F2, where R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group. The functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group.

[0040] In the embodiments of the present invention, the compound can contain a unit with the chemical structural formula F1-R-F2. When the compound is applied to prepare a solar cell, a modification layer can be prepared with the compound between the composite layer and the light absorption layer. Since the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, the modification layer can interact with the composite layer, modify the composite layer, and adjust the energy level of the composite layer, making the energy level of the composite layer more matched with the energy level of the light absorption layer, which is beneficial to the transmission and collection of holes and can avoid setting a dedicated hole transport layer for hole transmission. Since the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group, the modification layer can interact with the light absorption layer, passivate the defects of the light absorption layer, weaken the carrier recombination, and effectively improve the efficiency of the solar cell.

[0041] Optionally, the nitrogen-containing group may be selected from at least one of an amino group, a quaternary ammonium salt, an amidino group, an amide, and an imide; the sulfur-containing group may be selected from at least one of a thiol, a thioether, a sulfinyl group, a sulfonyl group, and a sulfonic acid group; the oxygen-containing group may be selected from at least one of a hydroxyl group, an ether oxygen, a siloxanyl group, a carboxyl group, an acid anhydride, an ester group, an aldehyde group, a ketone group, and an acyl halide group; the phosphorus-containing group may be selected from at least one of a phosphate group, a phosphoric acid ester group, and a phosphino group.

[0042] Specifically, the halogen group may be an ion, a simple substance, or a molecule of a halogen element. For example: Cl2, Br2, I2, Cl — , Br — , I — etc.

[0043] Specifically, the chemical structural formulas of the repeating unit of the organic small molecule and the polymer may be:

[0044] 3-aminopropyltrimethoxysilane;

[0045] , N-[(vinylphenyl)methyl]-N’-[3-(trimethoxysilyl)propyl]-1,2-ethylenediamine hydrochloride;

[0046] 3-aminopropane-1-phosphonic acid.

[0047] Optionally, the modified layer prepared from the compound can be used in a solar cell, and the modified layer can be laminated between the perovskite absorption layer and the composite layer.

[0048] Specifically, the composite layer can be prepared first, then the modified layer is prepared from the compound on the composite layer, and then the perovskite absorption layer is prepared on the surface of the modified layer facing away from the composite layer.

[0049] Specifically, since the modified layer can be prepared from the compound, the modified layer contains a functional group F1, which can interact with the composite layer, modify the composite layer, and adjust the energy level of the composite layer, so that the energy level of the composite layer and the energy level of the light absorption layer are more matched, which is beneficial to the transmission and collection of holes, and a hole transport layer specifically for transporting holes can be avoided. The modified layer also contains a functional group F2, which can interact with the light absorption layer, passivate the defects of the light absorption layer, weaken the carrier recombination, and effectively improve the efficiency of the solar cell.

[0050] The embodiment of the present invention also discloses a solar cell. Refer to Figure 1, which shows a schematic structural diagram of a solar cell according to the present invention. Specifically, it may include: a first electrode 1, a substrate cell 2, a composite layer 3, a modification layer 4, a light absorption layer 5, an electron transport layer 6, and a second electrode 8 stacked in sequence. Among them, the interface of the light absorption layer 5 close to the modification layer 4 is the first interface, and the interface of the composite layer 3 close to the modification layer 4 is the second interface; the modification layer 4 can interact with the light absorption layer 5 to passivate the defects of the first interface; the modification layer 4 can interact with the composite layer 3 to modify the second interface; the modification layer 4 can be prepared from the above-mentioned compound.

[0051] In an embodiment of the present invention, the modification layer 4 is disposed between the composite layer 3 and the light absorption layer 5, and the first interface of the light absorption layer 5 and the second interface of the composite layer 3 can both be disposed close to the modification layer 4. The compound contains a unit with a chemical structural formula of F1-R-F2. Since the functional group F2 contains at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group, the modification layer 4 can interact with the light absorption layer 5, passivate the defects of the first interface, weaken the carrier recombination, and effectively improve the efficiency of the solar cell. Since the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, the modification layer 4 can interact with the composite layer 3, modify the second interface, and adjust the energy level of the composite layer 3, making the energy level of the composite layer 3 more matched with the energy level of the light absorption layer 5, which is beneficial to the transmission and collection of holes, and can avoid setting a hole transport layer specifically for transporting holes.

[0052] In an embodiment of the present invention, the substrate cell 2 can be a silicon substrate cell, such as: a heterojunction cell, a PERC cell (Passivated Emitter and Rear Cell, passivated emitter back contact solar cell), etc.

[0053] Specifically, the light absorption layer 5 can absorb photons and excite carrier pairs. The carriers can include electrons and holes. The holes can recombine with the electrons transmitted to the composite layer 3 and its interface in the substrate cell 2 via the modification layer 4 and the composite layer 3. The holes in the substrate cell 2 that do not recombine with the electrons can continue to be transmitted to the first electrode 1 and be collected by the first electrode 1. The electrons can be transmitted to the second electrode 8 via the electron transport layer 6 and be collected by the second electrode 8.

[0054] Specifically, the electron transport layer 6 can be used to transport electrons, and the thickness of the electron transport layer 6 can be 1-50 nanometers. In practical applications, a transparent conductive film 7 can also be provided between the electron transport layer 6 and the second electrode 8. The material of the transparent conductive film 7 can be selected from one or more of semiconductor oxides such as ITO (indium tin oxide), AZO (Aluminum-doped zinc oxide), and IWO (Tungsten doped indium oxide), and the thickness of the transparent conductive film 7 can be 10-200 nanometers.

[0055] Specifically, both the first electrode 1 and the second electrode 8 can be metal electrodes, and the materials of the metal electrodes can include at least one of metal materials, carbon materials, and polymer conductive materials. The metal materials can specifically include Ag (silver), Au (gold), Cu (copper), Al (aluminum), Ni (nickel), etc. The thickness of the first electrode 1 can be 0.1-50 microns, and the thickness of the second electrode 8 can be 0.1-50 microns.

[0056] Exemplarily, the functional group F1 includes at least one of a silicon-containing group, a phosphate group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, so that the functional group F1 can fill the vacancies in the composite layer 3 or produce a coordination effect with the atoms that are not fully coordinated in the composite layer 3. The specific selection of the functional group F1 can be determined according to the materials actually used in the composite layer 3, as long as it is ensured that the functional group F1 can interact with the composite layer 3. The embodiments of the present invention do not make specific limitations in this regard.

[0057] Specifically, the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group, so that one type of functional group F2 can passivate one or more types of defects in the light absorption layer 5. The specific selection of the functional group F2 can be set according to actual needs. The embodiments of the present invention do not make specific limitations in this regard.

[0058] Optionally, the light absorption layer 5 can be a perovskite layer formed by inorganic materials, organic materials, or a hybrid of inorganic materials, and the composite layer 3 can be an inorganic layer formed by inorganic materials.

[0059] In the embodiments of the present invention, when the light absorption layer 5 is a perovskite layer and the composite layer 3 is an inorganic layer, the efficiency of the solar cell can be further improved, and the cost of the solar cell can be reduced.

[0060] Specifically, the modification layer 4 can interact with the light absorption layer 5 through the functional group F2 and interact with the composite layer 3 through the functional group F1.

[0061] Optionally, the functional group F1 can interact with the composite layer 3 in at least one of the ways of chemical bond, coordination bond, dipole interaction, and van der Waals force.

[0062] In the embodiments of the present invention, the functional group F1 can form a bonding interaction with the composite layer 3 through chemical bonds and coordination bonds, and can also form an electrostatic interaction with the composite layer 3 through dipole interaction and van der Waals force, which can effectively modify the second interface of the composite layer 3.

[0063] Optionally, the functional group F2 can interact with the light absorption layer 5 in at least one of the ways of chemical bond, hydrogen bond, coordination bond, dipole interaction, and van der Waals force.

[0064] In the embodiments of the present invention, the functional group F2 can interact with the ions in the light absorption layer 5 through chemical bonds, hydrogen bonds, and coordination bonds, and can also form an electrostatic interaction with the ions in the light absorption layer 5 through dipole interaction and van der Waals force, which can effectively passivate the defects at the first interface of the light absorption layer 5.

[0065] Optionally, the thickness of the modification layer 4 can be 0.1 - 10 nanometers. In the embodiments of the present invention, controlling the thickness of the modification layer 4 within 0.1 - 10 nanometers facilitates the effective transmission and collection of holes. In practical applications, it is also preferable to control the thickness of the modification layer 4 within 1 - 5 nanometers.

[0066] Optionally, the chemical structural formula of the light absorption layer 5 can be: ABX3, where A is a monovalent metal cation or an organic cation, B is a divalent metal cation, and X is a monovalent anion, which can improve the conversion efficiency of the light absorption layer 5. Specifically, A is a monovalent metal cation or an organic cation, such as: CH3NH3 cation, C4H9NH3 cation, NH2 cation, CHNH2 cation, Cs cation, etc.; B is a divalent metal cation, such as: Pb ion, Sn ion, etc.; X is a monovalent anion, such as: Cl ion, Br ion, or I ion, SCN ion, etc. (where C is carbon, H is hydrogen, N is nitrogen, Cs is cesium, Pb is lead, Sn is tin, Cl is chlorine, Br is bromine, I is iodine, S is sulfur).

[0067] Specifically, in order to facilitate the light absorption layer 5 to absorb photons, the thickness range of the light absorption layer 5 can be controlled within 200 - 5000 nanometers.

[0068] Optionally, the composite layer 3 can include at least one of a tunneling junction and a transparent conductive layer, which is convenient for improving the efficiency of hole transport.

[0069] Specifically, the material of the transparent conductive layer can be semiconductor oxides, semiconductor sulfides, etc., including but not limited to: ITO, AZO, IWO, SnO2 (tin dioxide), nc-Si:H(n) / nc-Si:H(p) (n-p type microcrystalline silicon), nc-Si:H(p) / nc-Si:H(n) (p-n type microcrystalline silicon), CuS (copper sulfide), ZnS (zinc sulfide).

[0070] In a third aspect, an embodiment of the present invention further provides a method for manufacturing a solar cell, as Figure 2 shown, which may specifically include the following steps:

[0071] Step 1: Provide a substrate cell. Specifically, the substrate cell can be a heterojunction cell or a PERC cell.

[0072] Step 2: Prepare a composite layer on one surface of the substrate cell.

[0073] Specifically, the material of the composite layer includes but is not limited to semiconductor oxides or semiconductor sulfides, etc.

[0074] Step 3: Prepare a modification layer on the surface of the composite layer facing away from the substrate cell using the above compound.

[0075] Specifically, the compound may contain a unit with the chemical formula F1-R-F2, where R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphate group, a carboxyl group, a carboxylate group, and a sulfonic acid group, and the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group. When preparing the solution of the modification layer, amides, alcohols, esters, ketones, ethers, sulfones / sulfoxides, etc. can be used as solvents, and the concentration of the solution of the modification layer can be 0.0001-1 mole per liter.

[0076] Optionally, the modification layer can be prepared on the composite layer by at least one of spin coating, soaking, fumigation, scraping, slot coating, spraying, printing, vacuum deposition, and film pulling.

[0077] Specifically, the modification layer can be prepared by at least one of spin coating, soaking, fumigation, scraping, slot coating, spraying, printing, vacuum deposition, and film pulling, which can improve the convenience and diversity of preparing the modification layer.

[0078] Step 4: Prepare a light absorption layer on the surface of the modification layer facing away from the composite layer.

[0079] Specifically, the step of preparing the light absorption layer on the modification layer may further include:

[0080] Step S11: Prepare a precursor layer of the light absorption layer on the modification layer. The processing methods of the precursor layer include at least one of spin coating, blade coating, slot die coating, spraying, printing, vacuum deposition, etc.;

[0081] Step S12: Treat the precursor layer by any one of heating, vapor phase method, anti-solvent method, vacuum solvent removal, etc. to form the light absorption layer.

[0082] Step Five: Prepare an electron transport layer on the surface of the light absorption layer facing away from the modification layer.

[0083] Specifically, the processing methods of the electron transport layer include at least one of vacuum deposition, spin coating, blade coating, slot die coating, spraying, printing, ALD (Atomic layer deposition), etc.

[0084] Step Six: Prepare a second electrode on the surface of the electron transport layer facing away from the modification layer.

[0085] Specifically, the processing methods for preparing the second electrode include at least one of evaporation coating, printing, electroplating, screen printing, etc.

[0086] Specifically, preparing the second electrode on the surface of the electron transport layer facing away from the modification layer includes:

[0087] Step S21: Prepare a transparent conductive film on the surface of the electron transport layer facing away from the modification layer.

[0088] Specifically, the transparent conductive film can be prepared by vacuum deposition.

[0089] Step S22: Prepare the second electrode on the surface of the transparent conductive film facing away from the electron transport layer.

[0090] Specifically, the processing methods for preparing the second electrode include at least one of evaporation coating, printing, electroplating, screen printing, etc.

[0091] Step Seven: Prepare a first electrode on the surface of the substrate cell facing away from the composite layer.

[0092] Specifically, the processing methods for preparing the first electrode include at least one of evaporation coating, printing, electroplating, screen printing, etc.

[0093] In practical applications, the following specific embodiments can be used to prepare the solar cell:

[0094] Example 1

[0095] Step A1: Prepare a tunneling junction on the light-incident surface side of the heterojunction cell by using the PECVD (Plasma Enhanced Chemical Vapor Deposition) process, and the thickness of the tunneling junction is 5 - 150 nanometers.

[0096] Step A2: Prepare a 3-aminopropyltrimethoxysilane modification layer on the surface of the tunneling junction facing away from the heterojunction cell, and a modification layer can be formed. Specifically, it can be prepared by spin coating or dipping. The solution of this modification layer can use alcohols such as isopropanol and ethanol as solvents, the solution concentration can be 1 - 50 millimoles per liter, the thickness can be 0.1 - 10 nanometers, preferably 1 - 5 nanometers.

[0097] Specifically, the structural formula of the 3-aminopropyltrimethoxysilane modification layer can be:

[0098] Step A3: Further prepare a perovskite precursor layer on the surface of the 3-aminopropyltrimethoxysilane modification layer away from the tunneling junction by spin coating. The composition of the perovskite precursor layer is prepared according to Cs 0.05 FA 0.75 MA 0.20 Pb(I 0.8 Br 0.2 )3, and PbI2, MAX (MA is methylammonium), and FAX (FA is formamidine) can be slightly in excess by 1% - 10% in molar amount. Heat the perovskite precursor layer to form a perovskite layer. Among them, the heating temperature can be 100 - 150 degrees Celsius, and the heating time can be 20 - 60 minutes. The thickness of the perovskite layer can be 500 nanometers.

[0099] Step A4: Prepare a C60 (fullerene) electron transport layer on the surface of the perovskite layer facing away from the 3-aminopropyltrimethoxysilane modification layer by thermal evaporation. Among them, the vacuum degree of thermal evaporation can be <1E -4 Pascal. Further, an SnO2 (tin dioxide) layer can be prepared by the ALD processing method. The thickness of the C60 electron transport layer can be 5 - 20 nanometers, and the thickness of the SnO2 layer can be 5 - 20 nanometers.

[0100] Step A5: Prepare an ITO layer on the surface of the C60 electron transport layer with an SnO2 layer facing away from the perovskite layer by using the PVD (Physical Vapor Deposition) processing method, and the thickness of the ITO layer is 10 - 150 nanometers.

[0101] Step A6: Prepare an Ag electrode on the surface of the ITO layer facing away from the C60 electron transport layer by thermal evaporation, which can form the second electrode. The thickness of the Ag electrode is 200 nanometers.

[0102] Step A7: Prepare an Ag electrode on the backlight side of the heterojunction cell by thermal evaporation, which can form the first electrode. The thickness of the Ag electrode is 200 nm.

[0103] Example 2

[0104] Step B1: Prepare a tunneling junction on the light-incident side of the heterojunction cell by PECVD process. The thickness of the tunneling junction can be 5 - 150 nanometers.

[0105] Step B2: Prepare an N-[(vinylphenyl)methyl]-N’-[3-(trimethoxysilyl)propyl]-1,2-ethylenediamine hydrochloride modification layer on the surface of the tunneling junction facing away from the heterojunction cell. Specifically, it can be prepared by spin coating or immersion, which can form the modification layer. The solution of the modification layer can use alcohols such as isopropanol and ethanol as solvents. The solution concentration can be 1 - 50 millimoles per liter, and the thickness can be 0.1 - 10 nanometers, preferably 1 - 5 nanometers.

[0106] Among them, the structural formula of the N-[(vinylphenyl)methyl]-N’-[3-(trimethoxysilyl)propyl]-1,2-ethylenediamine hydrochloride modification layer can be:

[0107] Step B3: Prepare a perovskite precursor on the surface of the N-[(vinylphenyl)methyl]-N’-[3-(trimethoxysilyl)propyl]-1,2-ethylenediamine hydrochloride modification layer facing away from the tunneling junction by vacuum evaporation; then spin coat an isopropanol and ethanol solution of organic amine salt on the perovskite precursor layer. The spin coating speed can be 3500 rpm (revolutions per minute), and the spin coating time can be 60 seconds; then, heat the perovskite precursor layer to generate a perovskite layer. The heating temperature can be 100 - 150 degrees Celsius, and the heating time can be 20 - 60 minutes. Among them, the composition of the perovskite precursor layer can be PbI2 / CsBr, the composition of the isopropanol and ethanol solution can be FAI:FABr = 60:6, and the thickness of the perovskite layer can be 500 nanometers.

[0108] Step B4: Prepare a C60 electron transport layer on the surface of the perovskite layer facing away from the modification layer by thermal evaporation. The vacuum degree of thermal evaporation < 1E -4Pascal; then, a SnO2 layer is formed on the C60 electron transport layer by an ALD process. The thickness of the C60 electron transport layer may be 5-20 nanometers, and the thickness of the SnO2 layer may be 5-20 nanometers.

[0109] Step B5: an ITO layer is prepared on the surface of the C60 electron transport layer prepared with the SnO2 layer on the side away from the perovskite layer by PVD processing. The thickness of the ITO layer can be 10 to 150 nanometers.

[0110] Step B6: A Ag electrode is prepared on the surface of the ITO layer facing away from the C60 electron transport layer by thermal evaporation to form a second electrode. The thickness of the Ag electrode can be 200 nanometers.

[0111] Step B7: A Ag electrode is prepared on the backlight side of the heterojunction cell by thermal evaporation to form a first electrode. The thickness of the Ag electrode can be 200 nanometers.

[0112] Example 3

[0113] Step C1: preparing an ITO composite layer on the light incident side of the heterojunction cell using a PVD process. The thickness of the ITO composite layer may be 5-50 nanometers.

[0114] Step C2: A 3-aminopropane-1-phosphate modification layer is prepared on the surface of the ITO composite layer facing away from the heterojunction battery. The modification layer can be formed by spin coating, spray coating, or immersion. The modification layer solution can be made of an alcohol such as isopropyl alcohol or ethanol. The solution concentration can be 1-50 millimoles per liter and the thickness can be 0.1-10 nanometers, preferably 1-5 nanometers. The structural formula of the 3-aminopropane-1-phosphate modification layer is:

[0115]

[0116] Step C3: a perovskite precursor layer is prepared on the surface of the 3-aminopropane-1-phosphate modified layer away from the ITO composite layer by spin coating, wherein the composition of the perovskite precursor layer is Cs 0.05 FA 0.75 MA 0.20 Pb(I 0.8 Br 0.2 )3, with PbI2, MAI, and FAI in a slight excess of 1% to 10% by mole. The perovskite precursor layer is then heated to form a perovskite layer. The heating temperature may be 100-150 degrees Celsius for 20-60 minutes. The perovskite layer may have a thickness of 500 nanometers.

[0117] Step C4: Prepare a C60 electron transport layer on the surface of the perovskite layer facing away from the modification layer by thermal evaporation. The degree of vacuum for thermal evaporation can be <1E -4 Pascal. Then, an SnO2 layer can be prepared on the C60 electron transport layer by ALD processing method. Among them, the thickness of the C60 electron transport layer can be 5 - 20 nanometers, and the thickness of the SnO2 layer can be 5 - 20 nanometers.

[0118] Step C5: Prepare an ITO layer on the surface of the C60 electron transport layer with the SnO2 layer facing away from the perovskite layer by PVD processing method. The thickness of the ITO layer can be 10 - 150 nanometers.

[0119] Step C6: Prepare an Ag electrode on the surface of the ITO layer facing away from the C60 electron transport layer by thermal evaporation to form a second electrode. The thickness of the Ag electrode can be 200 nanometers.

[0120] Step C7: Prepare an Ag electrode on the backlight side of the heterojunction cell by thermal evaporation to form a first electrode. The thickness of the Ag electrode can be 200 nanometers.

[0121] Comparative Example 1

[0122] The difference between Comparative Example 1 and Example 1 or Example 2 is that a hole transport layer is provided between the light absorption layer and the composite layer.

[0123] Step a1: Prepare a tunneling junction on the light-incident side of the heterojunction cell by PECVD (Plasma Enhanced Chemical Vapor Deposition) process. The thickness of the tunneling junction is 5 - 150 nanometers.

[0124] Step a2: Prepare a Spiro-TTB (English name: Spiro-TTB, 2,2',7,7'-tetra(N,N-di-tolyl)amino-spiro-bifluor, Chinese synonym: 2,2',7,7'-tetra(di-p-tolylamino)spiro-9,9'-bifluorene; 2,2',7,7'-tetra(N,N-di-p-tolyl)amino-9,9-spirobifluorene) hole transport layer on the surface of the tunneling junction facing away from the heterojunction cell by thermal evaporation. The degree of vacuum for thermal evaporation can be <1E -4 Pascal, and the evaporation rate is The thickness of the Spiro-TTB hole transport layer can be 5 - 30 nm.

[0125] Step a3: Further prepare a perovskite precursor layer on the surface of the hole transport layer facing away from the tunneling junction. The composition of the perovskite precursor layer is prepared according to Cs 0.05 FA 0.75 MA 0.20 Pb(I 0.8 Br 0.2 )3, and PbI2, MAX (MA is methylammonium), and FAX (FA is formamidine) can be slightly in excess by 1% - 10% in molar amount. Heat the perovskite precursor layer to form a perovskite layer. Among them, the heating temperature can be 100 - 150 degrees Celsius, and the heating time can be 20 - 60 minutes. The thickness of the perovskite layer can be 500 nanometers.

[0126] Step a4: Prepare a C60 (fullerene) electron transport layer on the surface of the perovskite layer facing away from the hole transport layer by thermal evaporation. Among them, the vacuum degree of thermal evaporation can be <1E -4 Pascal. Further, an SnO2 (tin dioxide) layer can be prepared by ALD processing method. The thickness of the C60 electron transport layer can be 5 - 20 nanometers, and the thickness of the SnO2 layer can be 5 - 20 nanometers.

[0127] Step a5: Prepare an ITO layer on the surface of the C60 electron transport layer with the SnO2 layer facing away from the perovskite layer by PVD (Physical Vapor Deposition) processing method. The thickness of the ITO layer is 10 - 150 nanometers.

[0128] Step a6: Prepare an Ag electrode on the surface of the ITO layer facing away from the C60 electron transport layer by thermal evaporation to form a second electrode. The thickness of this Ag electrode is 200 nanometers.

[0129] Step a7: Prepare an Ag electrode on the backlight side of the heterojunction battery by thermal evaporation to form a first electrode. The thickness of this Ag electrode is 200 nm.

[0130] The performance of the solar cell corresponding to Comparative Example 1 is shown in Table 1.

[0131] Comparative Example 2

[0132] The difference between Comparative Example 2 and Example 3 is that a hole transport layer is provided between the light absorption layer and the composite layer.

[0133] Step b1: Prepare an ITO composite layer on the light-incident side of the heterojunction battery by PVD process. The thickness of the ITO composite layer can be 5 - 50 nanometers.

[0134] Step b2: Prepare a hole transport layer on the surface of the ITO composite layer facing away from the heterojunction battery by spin coating. The preparation method of the hole transport layer is as follows: Prepare a chlorobenzene solution of Spiro-OMeTAD (Chinese name: 2,2,7,7-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9-spirobifluorene) with a concentration of 72.3 mg / mL and ultrasonically dissolve it for 10 min. Add 20 μL of an acetonitrile solution of Li-TFSI and 24 μL of 4-t-BP to 1 mL of the chlorobenzene solution of Spiro-OMeTAD, stir and set aside. Spin coat on the ITO composite layer to prepare a Spiro-OMeTAD hole transport layer. Set the spin coating speed to 3000 rpm and the spin coating time to 30 s.

[0135] Step b3: Prepare a perovskite precursor layer on the surface of the hole transport layer facing away from the ITO composite layer by spin coating. The composition of the perovskite precursor layer is prepared according to the ratio of Cs 0.05 FA 0.75 MA 0.20 Pb(I 0.8 Br 0.2 )3. PbI2, MAI, and FAI can be slightly in excess by 1%-10% in molar amount. Then heat the perovskite precursor layer to form a perovskite layer. The heating temperature can be 100-150 degrees Celsius, the heating time can be 20-60 minutes, and the thickness of the perovskite layer can be 500 nanometers.

[0136] Step b4: Prepare a C60 electron transport layer on the surface of the perovskite layer facing away from the hole transport layer by thermal evaporation. The vacuum degree of thermal evaporation can be <1E -4 Pascal. Then an SnO2 layer can be prepared on the C60 electron transport layer by ALD processing method. Among them, the thickness of the C60 electron transport layer can be 5-20 nanometers, and the thickness of the SnO2 layer can be 5-20 nanometers.

[0137] Step b5: Prepare an ITO layer on the surface of the C60 electron transport layer with the SnO2 layer facing away from the perovskite layer by PVD processing method. The thickness of the ITO layer can be 10-150 nanometers.

[0138] Step b6: Prepare an Ag electrode on the surface of the ITO layer facing away from the electron transport layer by thermal evaporation to form a second electrode. The thickness of the Ag electrode can be 200 nanometers.

[0139] Step b7: Prepare an Ag electrode on the backlight side of the heterojunction battery by thermal evaporation to form a first electrode. The thickness of the Ag electrode can be 200 nanometers.

[0140] Table 1 shows the performance parameters of the solar cells in each example and the comparative example.

[0141]

[0142] Summary: As can be seen from Table 1, the energy conversion efficiency of the solar cell in Example 1 can reach 24.46%, the open-circuit voltage is 1.716 V, and the short-circuit current is 20.61 mA / cm 2 , and the fill factor is 0.69. While the energy conversion efficiency of the solar cell in Comparative Example 1 can only reach 23.85%, the open-circuit voltage is 1.714 V, and the short-circuit current is 20.73 mA / cm 2 , and the fill factor is 0.67. Combining Figure 2 shows that after the hole and electron transport layer of the solar cell in Example 1 of the present invention is replaced by a modification layer, it has a higher open-circuit voltage and more excellent optoelectronic conversion performance.

[0143] Specifically, as can be seen from Table 1, the energy conversion efficiency of the solar cell in Example 2 can reach 24.69%, the open-circuit voltage is 1.718 V, and the short-circuit current is 20.84 mA / cm 2 , and the fill factor is 0.68. While the energy conversion efficiency of the solar cell in Comparative Example 1 can only reach 23.85%, the open-circuit voltage is 1.714 V, and the short-circuit current is 20.73 mA / cm 2 , and the fill factor is 0.67. Combining Figure 3 shows that after the hole and electron transport layer of the solar cell in Example 2 of the present invention is replaced by a modification layer, it has a higher open-circuit voltage and more excellent optoelectronic conversion performance.

[0144] Specifically, as can be seen from Table 1, the energy conversion efficiency of the solar cell in Example 3 can reach 25.50%, the open-circuit voltage is 1.719 V, and the short-circuit current is 20.9 mA / cm 2 , and the fill factor is 0.71. While the energy conversion efficiency of the solar cell in Comparative Example 2 can only reach 24.62%, the open-circuit voltage is 1.72 V, and the short-circuit current is 20.50 mA / cm 2 , and the fill factor is 0.70. Combining Figure 4 shows that after the hole and electron transport layer of the solar cell in Example 3 of the present invention is replaced by a modification layer, it has more excellent optoelectronic conversion performance and fill factor.

[0145] Therefore, it can be concluded from the experimental results that since the modification layer has functional groups that can passivate the upper interface and the lower interface of the composite layer at the same time, greatly reducing the loss caused by interface non-radiative recombination, the cells with interface modification all show high optoelectronic conversion performance and fill factor.

[0146] The solar cell provided by the embodiment of the present invention has at least the following advantages:

[0147] In the embodiment of the present invention, the compound may include a unit with a chemical structural formula of F1-R-F2. When the compound is applied to the preparation of a solar cell, the compound can be used to prepare a modification layer between the composite layer and the light absorption layer. Since the functional group F1 includes at least one of a silicon-containing group, a phosphate group, a phosphoric acid ester group, a carboxyl group, a carboxylic acid ester group, and a sulfonic acid group, the modification layer can interact with the composite layer, modify the composite layer, and adjust the energy level of the composite layer, so that the energy level of the composite layer and the energy level of the light absorption layer are more matched, which is beneficial to the transmission and collection of holes, and a dedicated hole transport layer for hole transmission can be avoided; since the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group, the modification layer can interact with the light absorption layer, passivate the defects of the light absorption layer, weaken the carrier recombination, and effectively improve the efficiency of the solar cell.

[0148] Each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0149] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they know the basic creative concept. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the embodiments of the present invention.

[0150] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or terminal device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or terminal device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or terminal device including the element.

[0151] The above has introduced in detail the application of a compound provided by the present invention in a solar cell, the solar cell and its preparation method. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. Application of a compound in a solar cell, characterized in that, The compound is formed by an organic small molecule or a polymer. The chemical structural formula of the repeating unit of the organic small molecule and the polymer is F1-R-F2, where R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphate group, a phosphoric acid ester group, and a carboxylic acid ester group; the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group; The modified layer prepared from the compound can be used in a solar cell, and the modified layer is stacked between the perovskite absorption layer and the composite layer; The composite layer is at least one of a tunneling junction and a transparent conductive layer.

2. The application according to claim 1, characterized in that, The nitrogen-containing group is selected from at least one of an amino group, a quaternary ammonium salt, an amidino group, an amide group, and an imide group; the sulfur-containing group is selected from at least one of a thiol group, a thioether group, a sulfoxide group, a sulfone group, and a sulfonic acid group; the oxygen-containing group is selected from at least one of a hydroxyl group, an ether oxygen group, a siloxanyl group, a carboxyl group, an acid anhydride group, an ester group, an aldehyde group, a ketone group, and an acyl halide group; the phosphorus-containing group is selected from at least one of a phosphate group, a phosphoric acid ester group, and a phosphino group.

3. A solar cell, characterized in that, Including: A first electrode, a substrate cell, a composite layer, a modified layer, a light absorption layer, an electron transport layer, and a second electrode stacked in sequence, where The interface of the light absorption layer close to the modified layer is the first interface, and the interface of the composite layer close to the modified layer is the second interface; The modified layer can interact with the light absorption layer to passivate the defects of the first interface; the modified layer can interact with the composite layer to modify the second interface; The modified layer is prepared from a compound; The compound is formed by an organic small molecule or a polymer. The chemical structural formula of the repeating unit of the organic small molecule and the polymer is F1-R-F2, where R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphate group, a phosphoric acid ester group, and a carboxylic acid ester group; the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group; The composite layer is at least one of a tunneling junction and a transparent conductive layer.

4. The solar cell according to claim 3, characterized in that, The nitrogen-containing group is selected from at least one of an amino group, a quaternary ammonium salt, an amidino group, an amide group, and an imide group; the sulfur-containing group is selected from at least one of a thiol group, a thioether group, a sulfoxide group, a sulfone group, and a sulfonic acid group; the oxygen-containing group is selected from at least one of a hydroxyl group, an ether oxygen group, a siloxanyl group, a carboxyl group, an acid anhydride group, an ester group, an aldehyde group, a ketone group, and an acyl halide group; the phosphorus-containing group is selected from at least one of a phosphate group, a phosphoric acid ester group, and a phosphino group.

5. The solar cell according to claim 3, wherein The light absorption layer is a perovskite layer formed by an inorganic material or a hybrid of an organic material and an inorganic material, and the composite layer is an inorganic layer formed by an inorganic material.

6. The solar cell according to claim 3, characterized in that, The functional group F1 interacts with the composite layer by at least one of a chemical bond, a coordination bond, a dipole interaction, and a van der Waals force; the functional group F2 interacts with the light absorption layer by at least one of a chemical bond, a hydrogen bond, a coordination bond, a dipole interaction, and a van der Waals force.

7. The solar cell according to claim 3, characterized in that, The thickness of the modified layer is 0.1-10 nanometers.

8. A method for preparing a solar cell, characterized in that, Including: Providing a substrate cell; Preparing a composite layer on one side surface of the substrate cell; A modification layer is prepared using a compound on the surface of the composite layer facing away from the substrate cell; An optical absorption layer is prepared on the surface of the modification layer facing away from the composite layer; An electron transport layer is prepared on the surface of the optical absorption layer facing away from the modification layer; A second electrode is prepared on the surface of the electron transport layer facing away from the modification layer; A first electrode is prepared on the surface of the substrate cell facing away from the composite layer; The compound is formed of an organic small molecule or a polymer, and the chemical structural formula of the repeating unit of the organic small molecule and the polymer is F1-R-F2, wherein R is a substituted or unsubstituted alkyl group, and the functional group F1 includes at least one of a silicon-containing group, a phosphoric acid group, a phosphoric acid ester group, and a carboxylic acid ester group, and the functional group F2 includes at least one of a halogen group, a nitrogen-containing group, a sulfur-containing group, an oxygen-containing group, and a phosphorus-containing group; The composite layer is at least one of a tunneling junction and a transparent conductive layer.

9. The method according to claim 8, wherein The nitrogen-containing group is selected from at least one of an amino group, a quaternary ammonium salt, an amidino group, an amide, and an imide, the sulfur-containing group is selected from at least one of a thiol, a thioether, a sulfinyl group, a sulfonyl group, and a sulfonic acid group, the oxygen-containing group is selected from at least one of a hydroxyl group, an ether oxygen, a siloxanyl group, a carboxyl group, an acid anhydride, an ester group, an aldehyde group, a ketone group, and an acyl halide group, and the phosphorus-containing group is selected from at least one of a phosphoric acid group, a phosphoric acid ester group, and a phosphino group.

10. The method according to claim 8, characterized in that, The modification layer can be prepared on the composite layer by at least one of spin coating, dipping, fumigation, blade coating, slot die coating, spraying, printing, vacuum deposition, and film drawing.

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