Solar cell, laminated solar cell, preparation method and photovoltaic module

Abstract

The invention relates to a solar cell, a laminated solar cell, a preparation method and a photovoltaic module. The solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite light absorption layer and an electrode layer which are stacked in sequence. And the hole transport layer comprises a polymer shown in a formula (I): # imgabs0 #. Wherein n is an integer between 10 and 10000, and Ar1 and Ar2 are independently a group as shown in a formula (II): # imgabs 1 #; wherein R is selected from H, a C1-C5 alkoxy group or a C1-C5 alkylthio group. The polymer contained in the hole transport layer of the solar cell and the laminated solar cell is connected with a phenoxazine group on a polyethylene carbon chain to serve as an electron accepting unit, and an electron donating group containing aniline fluorene is introduced on the phenoxazine group, so that the hole mobility is high, the energy level matched with perovskite is adjustable, and the hole transport layer can be used as an electron accepting unit. When the compound is used as an undoped hole transport material to be applied to a trans-perovskite solar cell, relatively high photoelectric conversion efficiency can be obtained.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a solar cell, a stacked solar cell, a preparation method, and a photovoltaic module. Background Art

[0002] In the construction of perovskite solar cells, the hole transport layer (HTL) has a significant impact on the device's photoelectric conversion efficiency and performance stability.

[0003] The hole mobility of traditional organic small molecule hole transport materials needs to be improved. For example, spiro-OMeTAD typically requires the addition of dopants such as tert-butylpyridine (t-BP) and lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) to enhance their conductivity and hole mobility. However, the addition of dopants not only increases production costs but can also have negative consequences. For example, the oxidized hole transport material formed during the doping process can interact with t-BP to form new pyridyl products, which can degrade device performance and negatively impact the long-term stability of the battery. Furthermore, the hygroscopicity of Li-TFSI can accelerate battery degradation, compromising long-term device stability. Furthermore, the use of dopants such as Li-TFSI complicates the device fabrication process, increasing battery production costs and hindering the commercialization of perovskite batteries.

[0004] Non-conjugated polymers have been used as hole transport materials in perovskite solar cells due to their low synthesis cost, excellent thin film processing and wettability, and high visible light transmittance. Recent research has shown that non-conjugated side-chain polyvinylcarbazole is a promising hole transport material due to its low cost, high thermal stability, and strong chemical modification. However, its energy level in quasi-two-dimensional inverse perovskites has not yet been well matched to the perovskite layer. Summary of the Invention

[0005] Based on this, the present invention provides a solar cell, a stacked solar cell, a preparation method, and a photovoltaic module to improve the hole mobility of the hole transport layer and the energy level matching with the perovskite.

[0006] The first aspect of the present invention is to provide a solar cell, the scheme is as follows:

[0007] A solar cell comprises a transparent conductive substrate, a hole transport layer, a perovskite light absorption layer and an electrode layer stacked in sequence;

[0008] The hole transport layer comprises a polymer represented by formula (I):

[0009] ;

[0010] Wherein, n is an integer between 10 and 10,000, and Ar1 and Ar2 are independently a group represented by formula (II):

[0011] ;

[0012] Wherein, R is selected from H, C1~C5 alkoxy or C1~C5 alkylthio, and * is a binding site.

[0013] In one embodiment, R is selected from C1-C3 alkoxy or C1-C3 alkylthio.

[0014] In one embodiment, R is selected from methoxy or methylthio.

[0015] The second aspect of the present invention is to provide a stacked solar cell, the scheme is as follows:

[0016] A stacked solar cell comprising a crystalline silicon bottom cell and a perovskite top cell, wherein the perovskite top cell comprises a transparent conductive layer, a hole transport layer, a perovskite light absorption layer and an electrode layer stacked in sequence;

[0017] The hole transport layer is located on a side of the transparent conductive layer away from the crystalline silicon bottom cell, and the hole transport layer comprises a polymer represented by formula (I):

[0018] ;

[0019] Wherein, n is an integer between 10 and 10,000, and Ar1 and Ar2 are independently a group represented by formula (II):

[0020] ;

[0021] Wherein, R is selected from H, C1~C5 alkoxy or C1~C5 alkylthio, and * is a binding site.

[0022] In one embodiment, R is selected from C1-C3 alkoxy or C1-C3 alkylthio.

[0023] In one embodiment, R is selected from methoxy or methylthio.

[0024] The third aspect of the present invention is to provide a method for preparing a solar cell, which is as follows:

[0025] A method for preparing a solar cell comprises the following steps:

[0026] A hole transport layer is prepared on a transparent conductive substrate, wherein the hole transport layer comprises a polymer represented by formula (I):

[0027] ;

[0028] Wherein, n is an integer between 10 and 10,000, and Ar1 and Ar2 are independently a group represented by formula (II):

[0029] ;

[0030] Wherein, R is selected from H, C1~C5 alkoxy or C1~C5 alkylthio, and * is a binding site;

[0031] preparing a perovskite light absorbing layer on the hole transport layer;

[0032] An electrode layer is prepared on the perovskite light absorbing layer.

[0033] In one embodiment, the method for preparing the polymer comprises the following steps:

[0034] Compound 1 undergoes a nucleophilic displacement reaction with compound 2 to obtain compound 3;

[0035] 、 、 ;

[0036] In the compound 2, X is a halogen;

[0037] The compound 3 is subjected to a lithiated boron esterification reaction with the compound 4 to obtain the compound 5;

[0038] 、 ;

[0039] Compound 6 is subjected to a halogenation reaction to obtain compound 7;

[0040] 、 ;

[0041] In the compound 7, X is a halogen;

[0042] The compound 7 is subjected to a Suzuki coupling reaction with the compound 5 to obtain compound 8;

[0043] ;

[0044] The compound 8 is subjected to a Wittig reaction to obtain compound 9;

[0045] ;

[0046] The compound 9 is subjected to a polymerization reaction to obtain the polymer.

[0047] In one embodiment, the nucleophilic displacement reaction comprises the following steps:

[0048] The compound 1, the compound 2 and the first catalyst are mixed and dissolved in a first solvent, and reacted at 85° C. to 95° C. for 8 h to 24 h.

[0049] In one embodiment, the lithiated boroesterification reaction comprises the following steps:

[0050] The compound 3 is dissolved in the second solvent, a second catalyst is added, and the reaction is carried out at -85°C to -75°C for 1 h to 2 h. The compound 4 is added, and the reaction is carried out at -85°C to -75°C for 1 h to 2 h, and then the reaction is continued at room temperature for 10 h to 16 h.

[0051] In one embodiment, the halogenation reaction comprises the following steps:

[0052] The compound 6 and the halogenating agent are mixed and dissolved in a third solvent, and reacted at -5°C to 0°C for 8h to 16h.

[0053] In one embodiment, the Suzuki coupling reaction comprises the following steps:

[0054] The compound 7, the compound 5, the alkaline agent and the third catalyst are mixed and dissolved in a fourth solvent, and reacted at 80° C. to 90° C. for 6 h to 12 h.

[0055] In one embodiment, the Wittig reaction comprises the following steps:

[0056] The compound 8, methyltriphenylphosphonium bromide and the fourth catalyst are mixed and dissolved in a fifth solvent, and reacted at 0° C. to 5° C. for 3 h to 5 h.

[0057] In one embodiment, the polymerization reaction comprises the following steps:

[0058] The compound 9 and the initiator are mixed in a sixth solvent, and the mixture is initiated at 65° C. to 70° C. for 2 h to 3 h, and then the reaction is continued at 85° C. to 90° C. for 72 h to 84 h.

[0059] A fourth aspect of the present invention is to provide a photovoltaic module, the solution of which is as follows:

[0060] A photovoltaic module comprises a first packaging component, a second packaging component, and a cell arranged between the first packaging component and the second packaging component, wherein the cell is the solar cell described in any of the above embodiments, the stacked solar cell described in any of the above embodiments, or a solar cell prepared by the preparation method described in any of the above embodiments.

[0061] Compared with traditional technologies, the above-mentioned solar cells, stacked solar cells, and photovoltaic modules have the following beneficial effects:

[0062] The polymer contained in the hole transport layer of the above-mentioned solar cells and stacked solar cells has a phenoxazine group connected to the polyethylene carbon chain as an electron-accepting unit, and an electron-donating group containing aniline fluorene is introduced on the phenoxazine group. The hole mobility is high, the energy level matches that of the perovskite and the energy level is adjustable. When used as an undoped hole transport material in an inverse perovskite solar cell, a higher photoelectric conversion efficiency can be obtained.

[0063] The above-mentioned photovoltaic module includes the solar cell described in any of the above-mentioned embodiments, the stacked solar cell described in any of the above-mentioned embodiments, or the solar cell prepared by the preparation method described in any of the above-mentioned embodiments, and thus has corresponding technical characteristics and can obtain corresponding beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 is a schematic structural diagram of a solar cell according to an embodiment;

[0065] Figure 2 is a schematic structural diagram of a stacked solar cell according to an embodiment;

[0066] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the hole transport material prepared in Example 1;

[0067] Figure 4 This is the hydrogen nuclear magnetic resonance spectrum of the hole transport material prepared in Example 2.

[0068] Description of reference numerals:

[0069] 100. Solar cell; 110. Transparent conductive substrate; 120. Hole transport layer; 130. Perovskite light absorption layer; 140. Electrode layer; 150. Electron transport layer; 200. Tandem solar cell; 210. Crystalline silicon bottom cell; 220. Perovskite top cell; 221. Transparent conductive substrate; 222. Hole transport layer; 223. Perovskite light absorption layer; 224. Electrode layer; 225. Electron transport layer. DETAILED DESCRIPTION

[0070] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0071] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0072] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing 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, and therefore should not be understood as limiting the present invention.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0074] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0075] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0076] The term "alkoxy" refers to a group having an -O-alkyl group, i.e., an alkyl group as defined above connected to a parent core structure via an oxygen atom. Phrases containing this term, for example, "C1-C5 alkoxy" refer to an alkyl group containing 1 to 5 carbon atoms, each occurrence of which can be independently a C1 alkoxy, C2 alkoxy, C3 alkoxy, C4 alkoxy, or C5 alkoxy group. Alkoxy groups can be straight-chain or branched. Suitable examples include, but are not limited to, methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt), and tert-butoxy (-OC(CH3)3 or -OtBu).

[0077] The term "alkylthio" refers to a group having an -S-alkyl group, i.e., an alkyl group as defined above connected to a core structure via a sulfur atom. Phrases containing this term, for example, "C1-C5 alkylthio" refer to an alkyl moiety containing 1 to 5 carbon atoms, each occurrence of which can be independently a C1 alkylthio, C2 alkylthio, C3 alkylthio, C4 alkylthio, or C5 alkylthio. Alkylthio groups can be straight-chain or branched. Suitable examples include, but are not limited to, methylthio (-S-CH3), ethylthio (-S-CH2CH3), and tert-butylthio (-SC(CH3)3).

[0078] "Halogen" refers to F, Cl, Br or I.

[0079] like Figure 1 As shown, Figure 1 As shown, a solar cell 100 according to an embodiment includes a transparent conductive substrate 110 , a hole transport layer 120 , a perovskite light absorbing layer 130 , and an electrode layer 140 , which are stacked in sequence.

[0080] The hole transport layer 120 comprises a polymer represented by formula (I).

[0081]

[0082] In formula (I), n is an integer between 10 and 10000. Ar1 and Ar2 are independently a group represented by formula (II).

[0083]

[0084] In formula (II), R is selected from H, C1-C5 alkoxy, or C1-C5 alkylthio. * represents the binding site.

[0085] The polymer contained in the hole transport layer of the above-mentioned solar cell connects a phenoxazine group to the polyethylene carbon chain as an electron-accepting unit, and introduces an electron-donating group containing aniline fluorene on the phenoxazine group. The hole mobility is high, the energy level matches that of the perovskite and the energy level is adjustable. When used as an undoped hole transport material in an inverse perovskite solar cell, a higher photoelectric conversion efficiency can be obtained.

[0086] R is selected from a C1-C3 alkoxy group or a C1-C3 alkylthio group. The introduction of an O atom or a S atom through the R group can interact with metal elements such as Pb in the perovskite material, thereby passivating grain boundary defects and interface defects without the addition of additives such as P-type dopants or interface modifiers.

[0087] R is selected from methoxy or methylthio. The shorter alkyl group in the R group is conducive to the interaction between the O atom or S atom and the metal elements such as Pb in the perovskite material.

[0088] The polymer contained in the hole transport layer 120 has the following advantages:

[0089] (1) The above polymers have good solubility in solvents such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane;

[0090] (2) The raw materials for the preparation of the above polymers are low-cost and the preparation process is simple, which is conducive to industrial production;

[0091] (3) The above-mentioned polymer has a high decomposition temperature, good thermal stability, good film-forming properties, and good wettability with the perovskite precursor solvent, which is conducive to the crystallization and film formation of perovskite;

[0092] (4) The hole mobility of the above polymers is good, which is conducive to the extraction and transmission of holes;

[0093] (5) The above polymers have a deep HOMO energy level that matches that of the perovskite material;

[0094] (6) The above polymers can be used in inverse quasi-two-dimensional perovskite solar cells without adding dopants, and are reproducible and have good application prospects.

[0095] The perovskite light absorbing layer 130 includes a perovskite precursor material (ABX3). A is a monovalent cation, including but not limited to one or more of potassium, methylamine, formamidine, methylenediamine, benzamidine, and guanidinium. B is a divalent cation, including but not limited to one or more of lead, copper, zinc, gallium, tin, and calcium. X is a monovalent anion, including but not limited to one or more of fluoride, chloride, bromide, iodide, thiocyanate, tetrafluoroborate, hexafluorophosphate, formate, and acetate.

[0096] In some examples, the perovskite light absorbing layer 130 is a quasi-two-dimensional perovskite, for example, the perovskite precursor material includes 3-bromobenzylammonium iodide or 3-chlorobenzylammonium iodide, methylammonium chloride, and lead iodide.

[0097] The material of the transparent conductive substrate 110 can be a conductive oxide, for example, one or more of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium tungsten oxide (IWO), indium cerium oxide (ICO), etc., but not limited to.

[0098] Optionally, the material of the electrode layer 140 may be, for example, but not limited to, one or more of gold, silver, copper, aluminum, and chromium.

[0099] Optionally, the solar cell 100 may further include an electron transport layer 150 , which is disposed between the perovskite light absorbing layer 130 and the electrode layer 140 .

[0100] Optionally, the material of the electron transport layer 150 may be, for example, but not limited to, one or more of 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi), 4,7-diphenyl-1,10-phenanthroline (Bphen), titanium dioxide, tin dioxide, zinc oxide, and fullerene derivatives, wherein the fullerene derivatives include one or more of indene-C60 bisadduct (ICBA), [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM), and [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM).

[0101] The present invention also provides a method for preparing the solar cell.

[0102] A hole transport layer is prepared on a transparent conductive substrate.

[0103] A perovskite light absorbing layer is prepared on the hole transport layer.

[0104] An electrode layer is prepared on the perovskite light absorbing layer.

[0105] In some examples, the method for preparing the polymer includes the following steps (steps S1 to S6):

[0106] Step S1, compound 1 and compound 2 undergo a nucleophilic displacement reaction to obtain compound 3.

[0107]

[0108] In the compound 2, X is a halogen, such as Br.

[0109] Exemplarily, the above nucleophilic displacement reaction comprises the following steps:

[0110] Compound 1, compound 2 and the first catalyst are mixed and dissolved in a first solvent, and reacted at 85° C. to 95° C. for 8 h to 24 h.

[0111] In some examples, the nucleophilic displacement reaction is performed under a protective atmosphere.

[0112] Illustratively, the molar ratio of Compound 1 to Compound 2 is 1:(1-1.5).

[0113] For example, the first catalyst includes, but is not limited to, sodium tert-butoxide, trisdibenzylideneacetone dipalladium, and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl.

[0114] Illustratively, the first solvent includes, for example, but is not limited to, toluene.

[0115] Step S2, subjecting compound 3 to a lithiated boron esterification reaction with compound 4 to obtain compound 5.

[0116]

[0117] Illustratively, the above-mentioned lithiated boron esterification reaction comprises the following steps:

[0118] Compound 3 is dissolved in the second solvent, a second catalyst is added, and the reaction is carried out at -85°C to -75°C for 1 h to 2. Compound 4 is added, and the reaction is carried out at -85°C to -75°C for 1 h to 2. The reaction is then carried out at room temperature for 10 h to 16 h.

[0119] In some examples, the lithiated boroesterification reaction is performed under a protective atmosphere.

[0120] Illustratively, the molar ratio of compound 3 to compound 4 is 1:(1.2-1.5), for example, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.

[0121] For example, the second solvent includes, but is not limited to, tetrahydrofuran (THF). Compound 3 is dissolved in the second solvent by, for example, stirring at -78°C for 10-20 minutes.

[0122] Illustratively, the second catalyst includes n-butyllithium.

[0123] Step S3, subjecting compound 6 to a halogenation reaction to obtain compound 7.

[0124]

[0125] In the compound 7, X is a halogen, such as Br.

[0126] Illustratively, the above halogenation reaction comprises the following steps:

[0127] Compound 6 and the halogenating agent are mixed and dissolved in a third solvent, and reacted at -5°C to 0°C for 8h to 16h.

[0128] In some examples, the halogenation reaction is performed under a protective atmosphere.

[0129] For example, the third solvent includes, but is not limited to, dichloromethane.

[0130] For example, the halogenating agent includes, but is not limited to, N-bromosuccinimide (NBS).

[0131] In the halogenation reaction, the molar ratio of compound 6 to the halogenating agent is 1:(2.2~3), for example, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, etc.

[0132] Step S4: Compound 7 is subjected to a Suzuki coupling reaction with compound 5 to obtain compound 8.

[0133]

[0134] Illustratively, the Suzuki coupling reaction comprises the following steps:

[0135] Compound 7, compound 5, an alkaline agent and a third catalyst are mixed and dissolved in a fourth solvent, and reacted at 80° C. to 90° C. for 6 h to 12 h.

[0136] In some examples, the Suzuki coupling reaction is performed under a protective atmosphere.

[0137] Illustratively, the fourth solvent is toluene, ethanol, and water in a volume ratio of 2:1:1.

[0138] Illustratively, the molar ratio of compound 7 to compound 5 is 1:(2.2-3), for example, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, etc.

[0139] Illustratively, the alkaline agent includes, for example, potassium carbonate.

[0140] Illustratively, the third catalyst includes, for example, tetrakis(triphenylphosphine)palladium.

[0141] Illustratively, the molar ratio of compound 7, the alkali agent, and the third catalyst is 1:(4-8):(0.01-0.1).

[0142] Step S5, subjecting compound 8 to a Wittig reaction to obtain compound 9.

[0143]

[0144] The Wittig reaction involves the following steps:

[0145] Compound 8, methyltriphenylphosphonium bromide and the fourth catalyst are mixed and dissolved in the fourth solvent, and reacted at 0° C. to 5° C. for 3 h to 5 h.

[0146] In some examples, the Wittig reaction is performed under a protective atmosphere.

[0147] Illustratively, the fourth solvent includes, but is not limited to, tetrahydrofuran.

[0148] Illustratively, the molar ratio of compound 8 to methyltriphenylphosphonium bromide is 1:(1-1.5), for example, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.

[0149] Illustratively, the fourth catalyst includes potassium tert-butoxide, for example.

[0150] Illustratively, the molar ratio of compound 8 to the fourth catalyst is 1:(1.3-1.5), for example, 1:1.3, 1:1.35, 1:1.4, 1:1.45, 1:1.5, etc.

[0151] Step S6, subjecting compound 9 to a polymerization reaction to obtain a polymer.

[0152] Exemplarily, the polymerization reaction comprises the following steps:

[0153] Compound 9 and the initiator are mixed in the sixth solvent, and the mixture is initiated at 65° C. to 70° C. for 2 h to 3 h, and then the reaction is continued at 85° C. to 90° C. for 72 h to 84 h.

[0154] The above polymerization reaction is carried out under a protective atmosphere.

[0155] Before the reaction, the reaction vessel is soaked and cleaned in potassium dichromate solution, then the salt layer on the inner wall is removed with saturated water vapor, and finally it is baked in a flame and cooled with nitrogen protection to achieve the purpose of removing oxygen on the bottle wall.

[0156] After adding compound 9 and the initiator into the reaction container, the reaction vessel is cooled using liquid nitrogen, vacuumed, heated, and then filled with nitrogen gas in a cycle of, for example, three times to remove oxygen from the system.

[0157] For example, the concentration of compound 9 in the initial reaction solution is 0.1 mol / L to 1.0 mol / L, and the concentration of the initiator is 1.0×10 -3 mol / L~10.0×10 -3 mol / L.

[0158] Illustratively, the sixth solvent includes at least one of toluene, tetrahydrofuran, and N-methylpyrrolidone.

[0159] For example, the initiator used in the polymerization reaction includes azobisisobutyronitrile (AIBN).

[0160] The hole transport layer can be prepared by preparing a solution of the aforementioned polymer, coating the solution on a substrate, and annealing the solution to form the hole transport layer. Examples of solvents used in the solution include, but are not limited to, dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane. Examples of coating methods include, but are not limited to, spin coating, printing, inkjet printing, and doctor blade coating.

[0161] The present invention also provides a stacked solar cell.

[0162] like Figure 2 As shown, a stacked solar cell 200 of an embodiment includes a crystalline silicon bottom cell 210 and a perovskite top cell 220, and the perovskite top cell 220 includes a transparent conductive layer, a hole transport layer 222, a perovskite light absorption layer 223 and an electrode layer 224 stacked in sequence.

[0163] The hole transport layer 222 is located on the side of the transparent conductive layer away from the crystalline silicon bottom cell 210. The hole transport layer 222 comprises the polymer represented by the above formula (I).

[0164] Optionally, the perovskite top cell 220 may further include an electron transport layer 225 , which is disposed between the perovskite light absorbing layer 223 and the electrode layer 224 .

[0165] The polymer contained in the hole transport layer 222 of the above-mentioned stacked solar cell 200 connects a phenoxazine group to the polyethylene carbon chain as an electron-accepting unit, and introduces an electron-donating group containing aniline fluorene on the phenoxazine group. The hole mobility is high, the energy level matches that of the perovskite and the energy level is adjustable. When it is used as an undoped hole transport material in an inverse perovskite solar cell, a higher photoelectric conversion efficiency can be obtained.

[0166] Furthermore, the present invention also provides a photovoltaic module.

[0167] A photovoltaic module according to an embodiment includes a first packaging component, a second packaging component, and a cell. The cell is the aforementioned solar cell, the aforementioned stacked solar cell, or a solar cell prepared by the aforementioned preparation method.

[0168] In some examples, the first packaging component includes a packaging panel and a first adhesive film disposed between the packaging panel and the battery cell. In some examples, the second packaging component includes a packaging backplane and a second adhesive film disposed between the packaging backplane and the battery cell.

[0169] The following specific examples are provided to further illustrate the present invention. The present invention provides the following specific examples for a better understanding of the present invention, but is not limited to the following specific examples and does not limit the content and scope of the present invention.

[0170] Example 1

[0171] The molecular structure of the polymer PV-POT-1 provided in this embodiment is shown in the following formula.

[0172]

[0173] The preparation method of the polymer PV-POT-1 provided in this embodiment includes the following steps:

[0174] Step 1, synthesis of compound 3:

[0175] See the reaction scheme below. Compound 1 (1.61 g, 5.11 mmol), compound 2 (1.02 g, 4.26 mmol), sodium tert-butoxide (0.61 g, 6.35 mmol), trisdibenzylideneacetone dipalladium (0.077 mg, 0.085 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.081 g, 0.169 mmol) were dissolved in toluene (30 mL) and added to a two-necked round-bottom flask. Under a nitrogen atmosphere, the mixture was heated to 110°C and stirred for 8 h. After the reaction, the mixture was cooled to room temperature and extracted with ethyl acetate. The organic layer was washed three times with 100 mL of brine and dried over MgSO. The solvent was removed under reduced pressure, and the mixture was purified by silica gel column chromatography (DCM:PE = 1:4 by volume) to obtain 1.48 g of compound 3 in a 73% yield.

[0176]

[0177] Step 2, synthesis of compound 5:

[0178] See the reaction scheme below. Compound 3 (4.74 g, 10 mmol) was weighed and placed in a 500 mL three-necked flask, followed by 30 mL of dry THF. The mixture was cooled to -78°C under N₂ and stirred for 10 min. Then, n-butyllithium (3.75 mL, 1.00 equiv, 1.6 M in n-hexane) was slowly added dropwise, and the reaction was allowed to proceed at -78°C for 1 h. Compound 4 (pinacol boronate, 2.75 mL, 15 mmol) was then added, and the reaction was continued at -78°C for 1 h. Finally, the mixture was brought to room temperature and the reaction continued for 12 h. The reaction was quenched with 50 mL of deionized water, followed by extraction with saturated NaCl solution and DCM. The organic phase was dried over anhydrous Mg₂SO₄, filtered, and purified by column chromatography (PE:DCM = 15:1 by volume) to obtain 4.8 g of compound 5 in 80% yield.

[0179]

[0180] Step 3, synthesis of compound 7:

[0181] See the reaction scheme below. Under nitrogen, a 100 mL round-bottom flask was charged with compound 6 (1.15 g, 4 mmol) and dichloromethane (10 mL), followed by N-bromosuccinimide (1.51 g, 8.48 mmol). The mixture was stirred at room temperature overnight. The reaction was quenched with water, extracted with dichloromethane, and the organic phase dried over anhydrous MgSO. The organic solvent was then removed by rotary evaporation to yield the crude product. The crude product was further purified by flash column chromatography using a 10:1 volume ratio of petroleum ether to dichloromethane as the eluent to afford 1.57 g of compound 7 in a 90% yield.

[0182]

[0183] Step 4, synthesis of compound 8:

[0184] See the reaction scheme below. Compound 5 (3.0 g, 5 mmol), compound 7 (0.89 g, 2 mmol), tetrakis(triphenylphosphine)palladium (57 mg, 0.05 mmol), and potassium carbonate (1.38 g, 10 mmol) were added to a 100 mL two-necked flask and dissolved in a 2:1:1 (volume ratio) mixture of toluene, ethanol, and water. The reaction was incubated at 85°C under nitrogen for 6 h. After cooling to room temperature, the reaction product was extracted with DCM, and the organic phase was dried over anhydrous MgSO, filtered, and evaporated under reduced pressure. Finally, the product was purified by column chromatography (PE:DCM = 6:1 (volume ratio)) to obtain 1.1 g of compound 8 in a 45% yield.

[0185]

[0186] Step 5, synthesis of compound 9:

[0187] See the reaction formula below. Methyltriphenylphosphonium bromide (0.47 g, 1.3 mmol) and potassium tert-butoxide (0.11 g, 1 mmol) were weighed and added to a 250 mL double-necked reaction flask. Under nitrogen, 10 mL of dry THF was added and stirred at 0°C for 1 hour. Compound 8 (1.23 g, 1 mmol) was weighed and dissolved in 10 mL of dry THF. Once completely dissolved, the mixture was slowly added dropwise to the reaction flask and allowed to react at 0°C for 4 hours. After completion of the reaction, 50 mL of deionized water was added to quench the reaction. The mixture was extracted with dichloromethane (DCM), and the organic phase was dried over anhydrous MgSO₄. The mixture was filtered, evaporated under reduced pressure, and purified by column chromatography (PE:DCM = 4:1 by volume) to yield 1.12 g of compound 9 in a 94% yield.

[0188]

[0189] Step 6, synthesis of PV-POT-1:

[0190] See the following reaction formula. Weigh 300 mg of compound 9 and 3 mg of azobisisobutyronitrile initiator recrystallized from ethanol and dissolve them in toluene. Freeze-dry with liquid nitrogen and evacuate for 1 minute, then fill with nitrogen. Repeat three times and seal. After initiation at 65°C for 3 hours, continue the reaction at 85°C for 72 hours. Quench the reaction with methanol, crystallize with n-hexane / dichloromethane, filter and dry, and use acetone as solvent to extract with a Soxhlet extractor for 72 hours to obtain 136 mg of polymer PV-POT-1. The hydrogen nuclear magnetic resonance spectrum of polymer PV-POT-2 is shown as follows: Figure 3 shown.

[0191]

[0192] Example 2

[0193] The molecular structure of the polymer PV-POT-2 provided in this embodiment is shown in the following formula.

[0194]

[0195] The preparation method of the polymer PV-POT-2 provided in this embodiment includes the following steps:

[0196] Step 1, synthesis of compound 3:

[0197] See the reaction scheme below. Compound 1 (1.72 g, 5.2 mmol), compound 2 (1.02 g, 4.26 mmol), sodium tert-butoxide (0.61 g, 6.35 mmol), trisdibenzylideneacetone dipalladium (0.077 mg, 0.085 mmol), and 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (0.081 g, 0.169 mmol) were dissolved in toluene (30 mL) and added to a two-necked round-bottom flask. Under a nitrogen atmosphere, the mixture was heated to 110°C and stirred for 8 h. After the reaction, the mixture was cooled to room temperature and extracted with ethyl acetate. The organic layer was washed three times with 100 mL of brine and dried over MgSO. The solvent was removed under reduced pressure, and the mixture was purified by silica gel column chromatography (DCM:PE = 1:4 by volume) to obtain 1.46 g of compound 3 in a 70% yield.

[0198]

[0199] Step 2, synthesis of compound 5:

[0200] See the reaction scheme below. Compound 3 (4.89 g, 10 mmol) was weighed and placed in a 500 mL three-necked flask, followed by 30 mL of dry THF. The mixture was cooled to -78°C under N₂ and stirred for 10 min. Then, n-butyllithium (3.75 mL, 1.00 equiv, 1.6 M in n-hexane) was slowly added dropwise, and the reaction was allowed to proceed at -78°C for 1 h. Compound 4 (pinacol boronate, 2.75 mL, 15 mmol) was then added, and the reaction was continued at -78°C for 1 h. Finally, the mixture was brought to room temperature and the reaction continued for 12 h. The reaction was quenched with 50 mL of deionized water, followed by extraction with saturated NaCl solution and DCM. The organic phase was dried over anhydrous Mg₂SO₄, filtered, and purified by column chromatography (PE:DCM = 15:1 by volume) to obtain 4.65 g of compound 5 in a 78% yield.

[0201]

[0202] Step 3, synthesis of compound 7:

[0203] See the reaction scheme below. Under nitrogen, a 100 mL round-bottom flask was charged with compound 6 (1.15 g, 4 mmol) and dichloromethane (10 mL), followed by N-bromosuccinimide (1.51 g, 8.48 mmol). The mixture was stirred at room temperature overnight. The reaction was quenched with water, extracted with dichloromethane, and the organic phase dried over anhydrous MgSO. The organic solvent was then removed by rotary evaporation to yield the crude product. The crude product was further purified by flash column chromatography using a 10:1 volume ratio of petroleum ether to dichloromethane as the eluent to afford 1.57 g of compound 7 in a 90% yield.

[0204]

[0205] Step 4, synthesis of compound 8:

[0206] See the reaction scheme below. Compound 5 (3.0 g, 5 mmol), compound 7 (0.89 g, 2 mmol), tetrakis(triphenylphosphine)palladium (57 mg, 0.05 mmol), and potassium carbonate (1.38 g, 10 mmol) were added to a 100 mL two-necked flask and dissolved in a 2:1:1 (volume ratio) mixture of toluene, ethanol, and water. The reaction was incubated at 85°C under nitrogen for 6 h. After cooling to room temperature, the reaction product was extracted with DCM, and the organic phase was dried over anhydrous MgSO, filtered, and evaporated under reduced pressure. Finally, the product was purified by column chromatography (PE:DCM = 6:1 (volume ratio)) to obtain 1.42 g of compound 8 in a 56% yield.

[0207]

[0208] Step 5, synthesis of compound 9:

[0209] See the reaction formula below. Methyltriphenylphosphonium bromide (0.47 g, 1.3 mmol) and potassium tert-butoxide (0.11 g, 1 mmol) were weighed and added to a 250 mL double-necked reaction flask. Under nitrogen, 10 mL of dry THF was added and stirred at 0°C for 1 hour. Compound 8 (1.23 g, 1 mmol) was weighed and dissolved in 10 mL of dry THF. Once completely dissolved, the mixture was slowly added dropwise to the reaction flask and allowed to react at 0°C for 4 hours. After completion of the reaction, 50 mL of deionized water was added to quench the reaction. The mixture was extracted with dichloromethane (DCM), and the organic phase was dried over anhydrous MgSO₄. The mixture was filtered, evaporated under reduced pressure, and purified by column chromatography (PE:DCM = 4:1 by volume) to yield 1.16 g of compound 9 in a 92% yield.

[0210]

[0211] Step 6, synthesis of PV-POT-2:

[0212] See the following reaction formula. Weigh 300 mg of compound 9 and 3 mg of azobisisobutyronitrile initiator recrystallized from ethanol and dissolve them in toluene. Freeze-dry with liquid nitrogen and evacuate for 1 minute, then fill with nitrogen. Repeat three times and seal. After initiation at 65°C for 3 hours, continue the reaction at 85°C for 72 hours. Quench the reaction with methanol, crystallize with n-hexane / dichloromethane, filter and dry, and use acetone as solvent to extract with a Soxhlet extractor for 72 hours to obtain 141 mg of polymer PV-POT-2. The hydrogen nuclear magnetic resonance spectrum of polymer PV-POT-2 is shown as follows: Figure 4 shown.

[0213]

[0214] Films were formed using the aforementioned polymers PV-POT-1 and PV-POT-2, respectively. A perovskite precursor solution was applied and annealed to form quasi-two-dimensional perovskite films. The crystallization growth of the quasi-two-dimensional perovskite films on the different polymers was studied using atomic force microscopes. The quasi-two-dimensional perovskite films based on PV-POT-1 and PV-POT-2 exhibited low RMS roughness of 13.2 nm and 14.6 nm, respectively. Therefore, the use of PV-POT-1 and PV-POT-2 as hole transport layers facilitates the diffusion and growth of the quasi-two-dimensional perovskite, resulting in dense, uniform, and smooth perovskite films.

[0215] The hole mobility of PV-POT-1 and PV-POT-2 was measured using the space charge limited current method. Specifically, single-hole devices were prepared with an ITO / PEDOT:PSS / HTMs / MoO3 / Ag structure. The thickness of each layer was determined using a step profiler. JV characteristic curves of the devices were obtained under dark conditions using a Keithley 2450 Source-Measure instrument. Nonlinear fitting analysis of the curves yielded the hole mobilities of the samples, as shown in Table 1.

[0216] Table 1 Hole mobility of PV-POT-1 and PV-POT-2

[0217]

[0218] The above test results show that both polymers have high hole mobility, which is beneficial to improving the fill factor (FF) of solar cells and obtaining better photovoltaic performance.

[0219] The polymers PV-POT-1 and PV-POT-2 prepared in the above examples were used as hole transport materials in perovskite solar cells. A control experimental group using the traditional hole transport material PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]) was also set up.

[0220] Specifically, the preparation process of perovskite solar cells includes the following steps:

[0221] Step 1: Prepare the transparent conductive substrate. Ultrasonic clean the ITO glass sheet with deionized water, acetone, and ethanol for 20 minutes, sequentially. Use an N2 airgun to blow away any residual solvent from the surface of the ITO glass sheet. Then, treat it with oxygen plasma for 15 minutes. This serves as the transparent conductive substrate and is then transferred to a nitrogen glove box.

[0222] Step 2: Preparation of the hole transport layer. Weigh 5 mg of the hole transport material and dissolve it in 1 mL of chlorobenzene. Apply 100 μl of the solution evenly onto a transparent conductive substrate. Spin coat at 5000 rpm for 25 seconds, then anneal at 100°C for 10 minutes to form the hole transport layer. The hole transport materials used in the different cells were polymers PV-POT-1, PV-POT-2, and PTAA, respectively.

[0223] Step 3: Preparation of the perovskite light-absorbing layer. 3-Fluoro-benzylammonium iodide (3FBAI), ammonium chloride (MACl), and lead iodide (PbI2) were mixed and dissolved in a 4:1 volume ratio of DMF and DMSO in a 2.2:3.5:4 molar ratio to form a perovskite solution. After forming the hole transport layer, the device was cooled to room temperature and preheated at 140°C for 4 minutes. 50 μl of the perovskite solution was then applied to the hole transport layer and spin-coated at 4000 rpm for 25 seconds. The perovskite light-absorbing layer was then annealed at 100°C for 10 minutes.

[0224] Step 4: Preparation of the electron transport layer. After forming the perovskite light absorption layer, the device was cooled to room temperature. 40 μl of a 15 mg / mL PC61BM solution was applied to the perovskite light absorption layer. The solution was spin-coated at 1000 rpm for 40 seconds and annealed at 80°C for 10 minutes to form the electron transport layer.

[0225] Step 5: Preparation of the electrode layer. After forming the electron transport layer, the device is transferred to a vacuum evaporation chamber, where a 6nm Cr layer and an 80nm Au layer are sequentially deposited on the electron transport layer to form the electrode layer, thus preparing an inverted quasi-two-dimensional perovskite solar cell.

[0226] The performance of perovskite solar cells using different hole transport materials was tested using the following method: the power of the solar simulator was adjusted to 100 mw / cm 2To simulate the AM1.5G radiation standard, the solar cell's current and voltage were read using a computer connected to a Keithley 2450 power meter. Light intensity was calibrated using a Newport 91150 standard silicon cell. The perovskite solar cell was tested in forward and reverse scanning modes at a scan rate of 0.05 V / s. The resulting electrical properties are shown in Table 2.

[0227] Table 2 Electrical properties of perovskite solar cells using different hole transport materials

[0228]

[0229] As shown in Table 2, using polymers PV-POT-1 and PV-POT-2 as hole transport materials improves the open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency of inverse perovskite solar cells compared to the traditional hole transport material PTAA. This indicates that polymers PV-POT-1 and PV-POT-2 have high hole mobility and good compatibility with the valence band of the quasi-two-dimensional perovskite.

[0230] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0231] The above-described embodiments merely represent several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be based on the appended claims, and the description may be used to interpret the content of the claims.

Claims

1. A solar cell, characterized in that: It includes a transparent conductive substrate, a hole transport layer, a perovskite light absorption layer and an electrode layer stacked in sequence; The hole transport layer comprises a polymer represented by formula (I): ； Wherein, n is an integer between 10 and 10,000, and Ar1 and Ar2 are independently a group represented by formula (II): ； Wherein, R is selected from H, C1~C5 alkoxy or C1~C5 alkylthio, and * is a binding site.

2. The solar cell according to claim 1, wherein R is selected from C1~C3 alkoxy or C1~C3 alkylthio.

3. The solar cell according to claim 2, wherein R is selected from methoxy or methylthio.

4. A stacked solar cell, characterized in that: It includes a crystalline silicon bottom cell and a perovskite top cell, wherein the perovskite top cell includes a transparent conductive layer, a hole transport layer, a perovskite light absorption layer and an electrode layer stacked in sequence; The hole transport layer is located on a side of the transparent conductive layer away from the crystalline silicon bottom cell, and the hole transport layer comprises a polymer represented by formula (I): ； Wherein, n is an integer between 10 and 10,000, and Ar1 and Ar2 are independently a group represented by formula (II): ； Wherein, R is selected from H, C1~C5 alkoxy or C1~C5 alkylthio, and * is a binding site.

5. The tandem solar cell according to claim 4, wherein: R is selected from C1~C3 alkoxy or C1~C3 alkylthio.

6. The tandem solar cell according to claim 5, wherein: R is selected from methoxy or methylthio.

7. A method for preparing a solar cell, characterized in that: The following steps are involved: A hole transport layer is prepared on a transparent conductive substrate, wherein the hole transport layer comprises a polymer represented by formula (I): ； Wherein, n is an integer between 10 and 10,000, and Ar1 and Ar2 are independently a group represented by formula (II): ； Wherein, R is selected from H, C1~C5 alkoxy or C1~C5 alkylthio, and * is a binding site; preparing a perovskite light absorbing layer on the hole transport layer; An electrode layer is prepared on the perovskite light absorbing layer.

8. The method for preparing a solar cell according to claim 7, wherein: The preparation method of the polymer comprises the following steps: Compound 1 undergoes a nucleophilic displacement reaction with compound 2 to obtain compound 3; 、 、 ； In the compound 2, X is a halogen; The compound 3 is subjected to a lithiated boron esterification reaction with the compound 4 to obtain the compound 5; 、 ； Compound 6 is subjected to a halogenation reaction to obtain compound 7; 、 ； In the compound 7, X is a halogen; The compound 7 is subjected to a Suzuki coupling reaction with the compound 5 to obtain compound 8; ； The compound 8 is subjected to a Wittig reaction to obtain compound 9; ； The compound 9 is subjected to a polymerization reaction to obtain the polymer.

9. The method for preparing a solar cell according to claim 8, wherein: The method for preparing the solar cell meets at least one of the following characteristics (1) to (6): (1) The nucleophilic displacement reaction comprises the following steps: The compound 1, the compound 2 and the first catalyst are mixed and dissolved in a first solvent, and reacted at 85° C. to 95° C. for 8 h to 24 h; (2) The lithiated boron esterification reaction comprises the following steps: Dissolve the compound 3 in the second solvent, add the second catalyst, react at -85°C to -75°C for 1 h to 2 h, add the compound 4, react at -85°C to -75°C for 1 h to 2 h, and continue to react at room temperature for 10 h to 16 h; (3) The halogenation reaction comprises the following steps: The compound 6 and the halogenating agent are mixed and dissolved in a third solvent, and reacted at -5°C to 0°C for 8h to 16h; (4) The Suzuki coupling reaction comprises the following steps: The compound 7, the compound 5, the alkaline agent and the third catalyst are mixed and dissolved in a fourth solvent, and reacted at 80° C. to 90° C. for 6 h to 12 h; (5) The Wittig reaction comprises the following steps: The compound 8, methyltriphenylphosphonium bromide, and the fourth catalyst are mixed and dissolved in a fifth solvent, and reacted at 0° C. to 5° C. for 3 h to 5 h; (6) The polymerization reaction comprises the following steps: The compound 9 and the initiator are mixed in a sixth solvent, and the mixture is initiated at 65° C. to 70° C. for 2 h to 3 h, and then the reaction is continued at 85° C. to 90° C. for 72 h to 84 h.

10. A photovoltaic module, characterized in that: The invention comprises a first packaging component, a second packaging component and a battery cell arranged between the first packaging component and the second packaging component, wherein the battery cell is the solar cell according to any one of claims 1 to 3, the stacked solar cell according to any one of claims 4 to 6, or the solar cell prepared by the preparation method according to any one of claims 7 to 9.

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