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

Abstract

The invention relates to a solar cell and a preparation method thereof, a laminated cell and a photovoltaic module. The solar cell comprises a first electrode, a hole transport layer, a perovskite light absorption layer and a second electrode, the hole transport layer is located between the first electrode and the perovskite light absorption layer, the perovskite light absorption layer is located between the hole transport layer and the second electrode, and the hole transport layer comprises a compound shown in the formula (I). According to the solar cell, a compound shown in a formula (I) is adopted as a hole transport layer material, in the compound shown in the formula (I), benzodithiophene serves as a molecular core, a structure shown in a formula (II-1) or a formula (II-2) serves as an end group, a phosphate group is introduced into the formula (II-1) and the formula (II-2), phosphorus-oxygen double bonds in the phosphate group can interact with perovskite, and therefore the hole transport layer is formed. And the defects in the perovskite light absorption layer are passivated, so that the solar cell obtains better photoelectric conversion efficiency.

Description

Technical Field

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

[0002] Perovskite solar cells have received extensive attention due to advantages such as long carrier diffusion distance, low preparation cost, and high light absorption coefficient. Among them, the hole transport layer in perovskite solar cells can not only extract and transport holes and block electrons, but also promote perovskite crystallization, and is an important part of perovskite solar cells. In traditional perovskite solar cells, the hole transport layer restricts the further improvement of the photoelectric conversion efficiency of the cells. Summary of the Invention

[0003] Based on this, the present application provides a solar cell with relatively high photoelectric conversion efficiency, a preparation method thereof, a tandem cell, and a photovoltaic module.

[0004] The technical solutions for solving the above technical problems in the present application are as follows.

[0005] In the first aspect of the present application, a solar cell is provided, including a first electrode, a hole transport layer, a perovskite light absorption layer, and a second electrode. The hole transport layer is located between the first electrode and the perovskite light absorption layer, and the perovskite light absorption layer is located between the hole transport layer and the second electrode. The hole transport layer includes a compound represented by formula (I):

[0006]

[0007] Wherein, R1 is selected from one of the structures represented by formula (II-1) and formula (II-2):

[0008]

[0009] L1 is selected from and one of them;

[0010] L2 is selected from one of C1-C6 alkylene groups;

[0011] R2 is selected from one of C1-C 10 alkyl groups;

[0012] R3 to R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C 10 alkyl groups, substituted or unsubstituted C1-C 10 alkoxy groups, substituted or unsubstituted C1-C 10 alkylthio groups, halogens, trifluoromethyl groups, hydroxyl groups, mercapto groups, cyano groups, amino groups, and substituted or unsubstituted C6-C 18 aryl groups.

[0013] Each occurrence of m is independently selected from the integers 1 to 3; each occurrence of n is independently selected from the integers 1 to 4;

[0014] X is selected from one of a single bond, an oxygen atom, C(R5)2 and NR6, and R5 to R6 are each independently selected from hydrogen and substituted or unsubstituted C1-C 10 alkyl;

[0015] The substituents of the substitution are each independently selected from one of C1-C4 alkyl, amino, halogen, nitro, hydroxy, mercapto, carboxyl and cyano.

[0016] In some embodiments, in the solar cell, in the compound represented by formula (I), L1 is selected from ;

[0017] And / or, L2 is selected from one of C2-C4 alkylene; optionally, L2 is selected from one of propylene and butylene;

[0018] And / or, R2 is selected from one of C4-C8 alkyl; optionally, R2 is selected from one of n-pentyl, n-hexyl and n-heptyl;

[0019] And / or, R3 to R4 are each independently selected from one of hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkylthio, halogen, trifluoromethyl, hydroxy, mercapto, cyano and amino; optionally, R3 to R4 are both hydrogen;

[0020] And / or, X is selected from one of a single bond, an oxygen atom and C(R5)2, and R5 is selected from hydrogen and substituted or unsubstituted C1-C4 alkyl; optionally, R5 is methyl.

[0021] In some embodiments, in the solar cell, the hole transport layer comprises a compound represented by formula (I-1):

[0022] 。

[0023] In some embodiments, in the solar cell, R1 is selected from one of the structures represented by formula (II-1-a) to formula (II-1-c):

[0024] 。

[0025] In some embodiments, in the solar cell, the hole transport layer comprises at least one of BT-Cz, BT-Ac and BT-POZ:

[0026] 。

[0027] In some of these embodiments, in the solar cell, the perovskite light-absorbing layer comprises ABX3, where A is a monovalent cation, B is a divalent metal cation, and X is a halogen anion; optionally, the monovalent cation comprises at least one of cesium ion, methylamine ion, ethylamine ion, formamidinium ion, benzylamine ion, and phenethylamine ion, and the halogen anion comprises at least one of lead ion, tin ion, and copper ion, and the halogen anion comprises at least one of bromide ion, chloride ion, and iodide ion;

[0028] And / or, the solar cell further comprises an electron transport layer, and the electron transport layer is located between the perovskite light-absorbing layer and the second electrode; optionally, the electron transport layer comprises at least one of metal oxides, fullerenes, and their derivatives.

[0029] The second aspect of the present application provides a method for manufacturing a solar cell, comprising the following steps:

[0030] Fabricate a hole transport layer on the first electrode;

[0031] Fabricate a perovskite light-absorbing layer on a side of the hole transport layer away from the first electrode;

[0032] Fabricate a second electrode on a side of the perovskite light-absorbing layer away from the hole transport layer;

[0033] The hole transport layer comprises a compound represented by formula (I):

[0034]

[0035] Wherein, R1 is selected from one of the structures represented by formula (II-1) and formula (II-2):

[0036]

[0037] L1 is selected from and one of them;

[0038] L2 is selected from one of C1-C6 alkylene groups;

[0039] R2 is selected from one of C1-C 10 alkyl groups;

[0040] R3 to R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C 10 alkyl groups, substituted or unsubstituted C1-C 10 alkoxy groups, substituted or unsubstituted C1-C 10 alkylthio groups, halogen, trifluoromethyl, hydroxyl, mercapto, cyano, amino, and substituted or unsubstituted C6-C 18 aryl groups;

[0041] Each occurrence of m is independently selected from the integers 1 to 3; each occurrence of n is independently selected from the integers 1 to 4;

[0042] X is selected from one of a single bond, an oxygen atom, C(R5)2 and NR6, and R5 to R6 are independently selected from one of hydrogen and substituted or unsubstituted C1-C 10 alkyl;

[0043] The substituents of the said substitution are independently selected from one of C1-C4 alkyl, amino, halogen, nitro, hydroxyl, mercapto, carboxyl and cyano.

[0044] In some embodiments, in the method for preparing a solar cell, the preparation of the compound shown in formula (I) comprises the following steps:

[0045] Mix one of the compound shown in formula (IV-1) and the compound shown in formula (IV-2) with the compound shown in formula (III), and successively carry out Stille coupling reaction and hydrolysis reaction to prepare the compound shown in formula (I);

[0046]

[0047] Wherein, Y is a halogen atom.

[0048] The third aspect of the present application provides a tandem cell, including the solar cell provided in the first aspect or the solar cell prepared by the method for preparing a solar cell provided in the second aspect.

[0049] The fourth aspect of the present application provides a photovoltaic module, including the solar cell provided in the first aspect, the solar cell prepared by the method for preparing a solar cell provided in the second aspect, or the tandem cell provided in the third aspect.

[0050] The solar cell provided by the present application uses the compound shown in formula (I) as the hole transport layer material. In the compound shown in formula (I), benzodithiophene is used as the molecular core, and the structure shown in formula (II-1) or formula (II-2) is used as the end group, and a phosphoric acid group is introduced into formula (II-1) and formula (II-2). The phosphorus-oxygen double bond in the phosphoric acid group can interact with the perovskite, passivate the defects in the perovskite light-absorbing layer, so that the solar cell obtains better photoelectric conversion efficiency. Description of the Drawings

[0051] To more clearly illustrate the technical solutions in the embodiments of the present application and more comprehensively understand the present application and its beneficial effects, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0052] Figure 1 Schematic structural diagram of a perovskite solar cell provided for an embodiment;

[0053] Figure 2 1H NMR spectrum of BT-Cz prepared in Example 1;

[0054] Figure 3 1H NMR spectrum of BT-Ac prepared in Example 2;

[0055] Figure 4 1H NMR spectrum of BT-POZ prepared in Example 3;

[0056] Figure 5 J-V curve diagram of the devices fabricated from BT-Cz, BT-Ac, and BT-POZ.

[0057] Reference numerals:

[0058] 100: Perovskite solar cell; 110: Transparent conductive electrode; 120: Hole transport layer; 130: Perovskite light-absorbing layer; 140: Electron transport layer; 150: Metal electrode. Detailed implementation manners

[0059] The following further describes the present application in detail in combination with the implementation manners and examples. It should be understood that these implementation manners and examples are only used to illustrate the present application and not to limit the scope of the present application. The purpose of providing these implementation manners and examples is to make the understanding of the disclosed content of the present application more thorough and comprehensive.

[0060] It should also be understood that the present application can be implemented in many different forms and is not limited to the implementation manners and examples described herein. Those skilled in the art can make various changes or modifications without departing from the connotation of the present application, and the equivalent forms obtained also fall within the protection scope of the present application. For example, the features described as part of one implementation manner can be combined in a suitable manner with another implementation manner to produce a new implementation manner. In addition, in the following description, a large number of specific details are given to provide a more comprehensive understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms used in the description of this application herein are for the purpose of describing embodiments and examples only, and are not intended to limit this application.

[0062] Unless otherwise stated or there is a contradiction, the terms or phrases used herein have the following meanings:

[0063] In this application, when it comes to "multiple", "diverse", "multiple times", etc., unless otherwise specified, it means greater than 2 or equal to 2 in quantity. For example, "one or more" means one or greater than or equal to two.

[0064] As used herein, "its combination", "any combination thereof", "any combination mode thereof", etc. include all suitable combination modes of any two or more than two items in the listed items.

[0065] In this application, the "suitable" in "suitable combination mode", "suitable mode", "any suitable mode", etc. is subject to being able to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0066] In this application, "preferred", "better", "more preferable", "preferably" are only used to describe embodiments or examples with better effects, and it should be understood that they do not constitute a limitation on the protection scope of this application. If there are multiple "preferred" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction relationship, each "preferred" is independent.

[0067] In this application, "further", "even further", "especially", etc. are used for descriptive purposes, indicating differences in content, but should not be understood as a limitation on the protection scope of this application.

[0068] In this application, "optionally", "optional", "optional" mean that it can be either present or absent, that is, it refers to any one of the two alternative schemes of "present" or "absent". If there are multiple "optional" in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction relationship, each "optional" is independent.

[0069] In this application, in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or quantity, nor can it be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0070] In this application, among the technical features described in an open-ended manner, it includes a closed technical solution composed of the listed features, and also includes an open technical solution containing the listed features.

[0071] In this application, regarding the numerical interval (i.e., numerical range), unless otherwise specified, the distribution of the selectable numerical values within this numerical interval is considered continuous, and it includes the two numerical endpoints of this numerical interval (i.e., the minimum value and the maximum value), as well as each numerical value between these two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers within this numerical interval, it includes the two endpoint integers of this numerical range, as well as each integer between the two endpoints, which is equivalent to directly listing each integer. When providing multiple numerical ranges to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein. The "numerical value" in this numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" is allowed to broadly include numerical interval types such as percentage intervals, ratio intervals, and ratio value intervals.

[0072] The temperature parameter in this application, unless otherwise specified, allows both constant temperature treatment and variation within a certain temperature interval. It should be understood that the said constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuation within a range such as ±5°C, ±4°C, ±3°C, ±2°C, ±1°C is allowed.

[0073] In this application, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, such as 20°C ± 5°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0074] In this application, regarding the unit of the data range, if there is only a unit after the right endpoint, it means that the units of the left endpoint and the right endpoint are the same. For example, 3~5 h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0075] All documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated by reference. Unless it conflicts with the object and / or technical solution of the invention of this application, the cited documents involved in this application are incorporated by reference in their entirety and for all purposes. When referring to cited documents in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also incorporated by reference. When referring to cited documents in this application, the examples and preferred modes of the relevant technical features cited can also be incorporated by reference into this application, but only to the extent that the application of this application can be implemented. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or be amended adaptively according to the description of this application.

[0076] In the specification of the embodiments of this application, the mass or weight of the relevant components mentioned not only can refer to the specific content of each component, but also can represent the proportional relationship of the mass or weight between each component. Therefore, as long as it is scaled up or down in proportion according to the content of the relevant components in the specification of the embodiments of this application, it is within the scope disclosed in the specification of the embodiments of this application. Specifically, the mass or weight described in the specification of the embodiments of this application can be units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0077] In this application, "substituted or unsubstituted" in which "substituted" means that the hydrogen atom in the group is replaced by a substituent, and "unsubstituted" in "substituted or unsubstituted" means that the hydrogen atom in the group is not replaced by other atoms or atomic groups. In "substituted or unsubstituted C1-C 10 alkyl", the number of carbon atoms in "C1-C 10 alkyl" does not include the carbon atoms in the substituent. "C4-C8 alkyl" means that the hydrogen atoms in the group are not replaced by other atoms or atomic groups, and so on for the rest.

[0078] One embodiment of this application provides a solar cell, including a first electrode, a hole transport layer, a perovskite light absorption layer, and a second electrode. The hole transport layer is located between the first electrode and the perovskite light absorption layer, and the perovskite light absorption layer is located between the hole transport layer and the second electrode. The hole transport layer includes a compound represented by formula (I):

[0079]

[0080] Wherein, R1 is selected from one of the structures represented by formula (II-1) and formula (II-2):

[0081]

[0082] L1 is selected from and one of them;

[0083] L2 is selected from one of C1-C6 alkylene groups;

[0084] R2 is selected from one of C1-C 10 alkyl groups;

[0085] R3 to R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C 10 alkyl groups, substituted or unsubstituted C1-C 10 alkoxy groups, substituted or unsubstituted C1-C 10 alkylthio groups, halogens, trifluoromethyl, hydroxyl, mercapto, cyano, amino and substituted or unsubstituted C6-C 18 aryl groups;

[0086] Each occurrence of m is independently selected from integers of 1 to 3; each occurrence of n is independently selected from integers of 1 to 4;

[0087] X is selected from one of a single bond, an oxygen atom, C(R5)2 and NR6, and R5 to R6 are each independently selected from hydrogen and substituted or unsubstituted C1-C 10 alkyl groups;

[0088] The substituents of the substitution are each independently selected from one of C1-C4 alkyl groups, amino, halogen, nitro, hydroxyl, mercapto, carboxyl and cyano.

[0089] The solar cell provided by this application uses the compound shown in formula (I) as the hole transport layer material. In the compound shown in formula (I), benzodithiophene is used as the molecular core, and the structure shown in formula (II-1) or formula (II-2) is used as the end group, and a phosphoric acid group is introduced into formula (II-1) and formula (II-2). The phosphorus-oxygen double bond in the phosphoric acid group can interact with the perovskite, passivate the defects in the perovskite light-absorbing layer, so that the solar cell can obtain better photoelectric conversion efficiency.

[0090] The compound shown in formula (I) has a low synthesis cost, good solubility, film-forming property, high hole mobility and energy levels matching with the perovskite. When it is used as an undoped hole transport material in perovskite solar cells, better photoelectric conversion efficiency can be obtained.

[0091] The compound shown in formula (I) belongs to organic materials. Compared with inorganic materials, it has the following advantages: (1) various chemical properties, and according to different molecular structures, various optimizations can be carried out, so that the material has better photoelectric properties and hole transport rate; (2) it can be processed more conveniently, and the film-forming effect is remarkable; (3) cheap raw materials can be obtained very conveniently; (4) it can be prepared into flexible thin films and is easy to be processed into various shapes to adapt to the use in different environments.

[0092] It can be understood that the solar cell provided in this application is a perovskite solar cell.

[0093] In some of these examples, in the solar cell, in the compound represented by formula (I), L1 is selected from .

[0094] It can be understood that C1-C6 alkylene refers to an alkylene containing 1-6 carbon atoms, including but not limited to at least one of methylene (-CH2-), ethylene (-CH2CH2-), propylene (-CH2CH2CH2-), butylene (-CH2CH2CH2CH2-), pentylene (-CH2CH2CH2CH2CH2-), hexylene (-CH2CH2CH2CH2CH2CH2-), etc.; C1-C 10 alkyl refers to an alkyl having 1-10 carbon atoms, which can be straight-chain or branched-chain; further, the number of carbon atoms in C1-C 10 includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10; in some examples, it can be within the range formed by any two of these point values as the end values, the same below; C1-C 10 alkoxy refers to an alkoxy containing 1-10 carbon atoms; C1-C 10 alkylthio refers to an alkylthio containing 1-10 carbon atoms; C6-C 18 aryl refers to an aromatic ring having 6-18 carbon atoms; m and n refer to the number of substituents, m includes 1, 2 or 3, n includes 1, 2, 3 or 4, respectively substituting the hydrogen on the benzene ring; it can also be understood that when R3 is 2 and / or 3, each R3 can be the same or different; or when R4 is 2-4, different R4s can be the same or different.

[0095] In some of these examples, in the solar cell, L2 is selected from one of C2-C4 alkylene; optionally, L2 is selected from one of propylene and butylene.

[0096] In some of these examples, in the solar cell, R2 is selected from one of C4-C8 alkyl; optionally, R2 is selected from one of n-pentyl, n-hexyl and n-heptyl.

[0097] Adding alkyl chains to both ends of the two dithiophenes in benzodithiophene can make the hole transport layer material have better solubility, improve the uniformity of the hole transport layer, and thus improve the optoelectronic performance of the battery.

[0098] In some of these examples, in the solar cell, R3-R4 are each independently selected from one of hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C1-C4 alkylthio, halogen, trifluoromethyl, hydroxyl, mercapto, cyano and amino; optionally, R3-R4 are all hydrogen.

[0099] In some of these examples, in the solar cell, X is selected from one of a single bond, an oxygen atom, and C(R5)2, and R5 is selected from hydrogen and a substituted or unsubstituted C1-C4 alkyl group; optionally, R5 is a methyl group.

[0100] In some of these examples, in the solar cell, the hole transport layer comprises a compound represented by formula (I-1):

[0101] .

[0102] In some of these examples, in the solar cell, R1 is selected from one of the structures represented by formula (II-1-a) to formula (II-1-c):

[0103] .

[0104] It can be understood that (II-1-a) to formula (II-1-c) correspond to a carbazole phosphate, an acridine phosphate, or a phenoxazine phosphate group respectively, and R1 is simultaneously located at the 2,6-positions of the benzodithiophene core.

[0105] In some of these examples, in the solar cell, the hole transport layer comprises at least one of BT-Cz, BT-Ac, and BT-POZ:

[0106] .

[0107] Using BT-Cz, BT-Ac, and BT-POZ as hole transport layer materials, with benzodithiophene as the molecular core, carbazole, acridine, or phenoxazine as end groups at both ends of the two thiophene rings in benzodithiophene respectively, and a phosphate group is introduced into carbazole, acridine, or phenoxazine, further passivating the defects in the perovskite light-absorbing layer; at the same time, alkyl chains are added at both ends of the two bithiophenes in benzodithiophene, making the hole transport layer material have good solubility and improving the uniformity of the hole transport layer; thereby further improving the photoelectric conversion efficiency of the solar cell.

[0108] BT-Cz, BT-Ac, and BT-POZ have good solubility in solvents such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane.

[0109] BT-Cz, BT-Ac, and BT-POZ have good mobilities, which are beneficial to the extraction and transport of holes.

[0110] BT-Cz, BT-Ac, and BT-POZ have a relatively deep HOMO energy level that matches the perovskite.

[0111] BT-Cz, BT-Ac, and BT-POZ can be used in perovskite solar cells without doping any additives and have repeatability.

[0112] In some of these examples, in the solar cell, the thickness of the hole transport layer is 20 nm to 100 nm.

[0113] It can be understood that in the hole transport layer, the compound shown in formula (I) can be used alone as the hole transport material, or the compound shown in formula (I) can be used in combination with other hole transport materials, such as in combination with carbazole-based hole materials (2PACZ, MEO-2PACZ, 4PACz, Me-4PACz, etc.).

[0114] In some of these examples, in the solar cell, the perovskite light-absorbing layer includes ABX3, where A is a monovalent cation, B is a divalent metal cation, and X is a halogen anion.

[0115] Optionally, the monovalent cation includes at least one of cesium ion, methylamine ion, ethylamine ion, formamidinium ion, benzylamine ion, and phenethylamine ion.

[0116] Optionally, the divalent metal cation includes at least one of lead ion, tin ion, and copper ion.

[0117] Optionally, the halogen anion includes at least one of bromide ion, chloride ion, and iodide ion.

[0118] In some of these examples, in the solar cell, the solar cell further includes an electron transport layer, and the electron transport layer is located between the perovskite light-absorbing layer and the second electrode.

[0119] Optionally, the electron transport layer includes at least one of metal oxides, fullerenes, and their derivatives.

[0120] Furthermore, the metal oxides include but are not limited to at least one of tin oxide, zinc oxide, etc.; the fullerenes and their derivatives include at least one of C60, PC61BM, PC71BM, etc.

[0121] At least one of the first electrode and the second electrode is a transparent conductive electrode (transparent conductive oxide TCO), and the other is one of a transparent conductive electrode and a metal electrode; optionally, the transparent conductive electrode includes but is not limited to at least one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), antimony-doped tin oxide (ATO), etc.; the metal electrode includes but is not limited to at least one of chromium (Cr), gold (Au), silver (Ag), copper (Cu), aluminum (Al), etc.

[0122] Perovskite solar cells (PSCs) include normal perovskite solar cells (n-type) and inverted perovskite solar cells (p-type); in a normal perovskite solar cell, from bottom to top, there are a transparent conductive oxide, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal electrode in sequence; in an inverted perovskite solar cell, the positions of the electron transport layer and the hole transport layer are reversed, and its structure is usually a transparent conductive oxide, a hole transport layer, a perovskite light absorption layer, an electron transport layer, and a metal electrode from bottom to top.

[0123] In some of these examples, the perovskite solar cell is an inverted perovskite solar cell. That is, the first electrode is a transparent conductive electrode. Further, the second electrode is a metal electrode; optionally, the second electrode includes chromium and copper.

[0124] In an inverted perovskite solar cell, the compound shown in formula (I) serves as an important hole transport material (HTMs) between the perovskite layer and the transparent electrode, which is not only responsible for hole extraction and transport, blocking the flow of electrons, but also directly affects the crystallization and film formation of perovskite, playing a decisive role in improving the performance of the battery and realizing large-area commercial applications.

[0125] See Figure 1 , in some of these examples, the inverted perovskite solar cell 100 includes a transparent conductive electrode 110 (the first electrode), a hole transport layer 120, a perovskite light absorption layer 130, an electron transport layer 140, and a metal electrode 150 (the second electrode) stacked in sequence.

[0126] An embodiment of the present application provides a method for preparing a solar cell, including the following steps:

[0127] Prepare a hole transport layer on the first electrode;

[0128] Prepare a perovskite light absorption layer on the side of the hole transport layer away from the first electrode;

[0129] Prepare a second electrode on the side of the perovskite light absorption layer away from the hole transport layer;

[0130] The hole transport layer includes the compound shown in formula (I):

[0131]

[0132] Wherein, R1 is selected from one of the structures shown in formula (II-1) and formula (II-2):

[0133]

[0134] L1 is selected from and one of them;

[0135] L2 is selected from one of C1-C6 alkylene groups;

[0136] R2 is selected from one of C1-C 10 alkyl;

[0137] R3 to R4 are each independently selected from hydrogen, substituted or unsubstituted C1-C 10 alkyl, substituted or unsubstituted C1-C 10 alkoxy, substituted or unsubstituted C1-C 10 alkylthio, halogen, trifluoromethyl, hydroxyl, mercapto, cyano, amino and substituted or unsubstituted C6-C 18 aryl;

[0138] Each occurrence of m is independently selected from an integer of 1 to 3; each occurrence of n is independently selected from an integer of 1 to 4;

[0139] X is selected from one of a single bond, an oxygen atom, C(R5)2 and NR6, and R5 to R6 are each independently selected from hydrogen and substituted or unsubstituted C1-C 10 alkyl;

[0140] The substituents of the substitution are each independently selected from one of C1-C4 alkyl, amino, halogen, nitro, hydroxyl, mercapto, carboxyl and cyano.

[0141] In some examples, in the method for preparing a solar cell, the preparation of the compound represented by formula (I) includes step S10:

[0142] Mixing one of the compound represented by formula (IV-1) and the compound represented by formula (IV-2) with the compound represented by formula (III) and successively carrying out a Stille coupling reaction and a hydrolysis reaction to prepare the compound represented by formula (I);

[0143]

[0144] wherein, Y is a halogen atom.

[0145] It is understood that the halogen atom includes but is not limited to F, Cl, Br, I.

[0146] In some examples, in step S10, the Stille coupling reaction is carried out under the action of a palladium catalyst; optionally, the palladium catalyst includes Pd(PPh3)4.

[0147] In some examples, in step S10, the molar ratio of one of the compound represented by formula (IV-1) and the compound represented by formula (IV-2), the compound represented by formula (III) to the palladium catalyst is 1:2.2 to 3:0.05 to 0.15.

[0148] It is understandable that the mass ratio of one of the compounds represented by formula (IV-1) and the compound represented by formula (IV-2) to the compound represented by formula (III) is 1:2.2 to 3; the molar ratio of one of the compounds represented by formula (IV-1) and the compound represented by formula (IV-2) to the palladium catalyst is 1:0.05 to 0.15. Further, it is understandable that the mass ratio of one of the compounds represented by formula (IV-1) and the compound represented by formula (IV-2) to the compound represented by formula (III) includes but is not limited to 1:2.2, 1:2.5, 1:2.8, 1:3; the molar ratio of one of the compounds represented by formula (IV-1) and the compound represented by formula (IV-2) to the palladium catalyst includes but is not limited to 1:0.05, 1:0.08, 1:0.1, 1:0.15.

[0149] In some of these examples, in step S10, the Stille coupling reaction is carried out in the presence of an organic solvent. Optionally, the organic solvent includes toluene.

[0150] In some of these examples, in step S10, the temperature of the Stille coupling reaction is 110 °C to 120 °C. Further, the time of the Stille coupling reaction is 36 h to 50 h.

[0151] It is understandable that the temperature of the Stille coupling reaction includes but is not limited to 110 °C, 112 °C, 115 °C, 118 °C, 120 °C; the time of the Stille coupling reaction includes but is not limited to 36 h, 40 h, 45 h, 50 h.

[0152] In some of these examples, in step S10, the Stille coupling reaction is carried out under light-shielded conditions.

[0153] In some of these examples, in step S10, the Stille coupling reaction is carried out under inert gas conditions.

[0154] It is understandable that taking the compound represented by formula (IV-1) as the reaction substrate as an example, the compound prepared by the Stille coupling reaction is as shown in formula (V):

[0155] .

[0156] In some of these examples, in step S10, the hydrolysis reaction includes:

[0157] Mix the compound prepared by the Stille coupling reaction and an organic solvent, and add trimethylbromosilane dropwise for reaction.

[0158] Further, the hydrolysis reaction includes the following steps:

[0159] Under the protection of inert gas, the compound prepared by the Stille coupling reaction is dissolved in an organic solvent, trimethylsilyl bromide is added dropwise, and then stirred overnight. Optionally, the organic solvent includes 1,4-dioxane; the organic solvent is removed by a rotary evaporator to obtain a solid powder; the solid powder is dissolved in methanol, and then deionized water is added dropwise until the mixture becomes opaque, and then stirred. Optionally, the stirring time is 10 h to 16 h; the crude product is collected by filtration and washed with deionized water; then dissolved in THF and reprecipitated in acetone, and the compound shown in formula (I) is obtained by filtration. Optionally, the molar ratio of the compound prepared by the Stille coupling reaction to trimethylsilyl bromide is 1:8 to 15.

[0160] In some of these examples, the preparation of the compound shown in formula (III) includes step S20:

[0161] The compound shown in formula (VI), trimethyltin chloride, n-butyllithium and tetrahydrofuran are mixed to carry out a substitution reaction to prepare the compound shown in formula (III);

[0162] 。

[0163] In some of these examples, in step S20, the molar ratio of the compound shown in formula (V), n-butyllithium, and trimethyltin chloride is 1:1.2 to 3:2.2 to 4.

[0164] Further, step S20 includes the following steps:

[0165] Under the protection of inert gas, the compound shown in formula (VI) is added to a three-necked flask, THF is added, and the mixture is cooled to -78 °C and stirred. Optionally, the stirring time is 10 min to 20 min; then n-butyllithium is slowly added dropwise, and the reaction is carried out at -78 °C. Optionally, the reaction time at -78 °C is 1 h to 3 h; then the reaction is carried out at room temperature. Optionally, the reaction time at room temperature is 40 min to 60 min; it is placed at -78 °C again, trimethyltin chloride is added, and after low-temperature stirring reaction, the reaction is carried out at room temperature. Optionally, the low-temperature stirring reaction time is 10 min to 20 min, and optionally, the room temperature reaction time is 1 h to 3 h; finally, the reaction is terminated by adding water.

[0166] Further, in step S20, there is also a post-treatment step: extraction with diethyl ether, washing successively with saturated sodium chloride aqueous solution, drying with anhydrous magnesium sulfate, and after the crude product removes the excess mixed solvent by a rotary evaporator, it is purified by silica gel column chromatography to obtain the compound shown in formula (III).

[0167] In some of these examples, the preparation of the compound shown in formula (VI) includes step S30:

[0168] The compound shown in formula (VII), the compound shown in formula (VIII), n-butyllithium, SnCl2·2H2O and tetrahydrofuran are mixed for a substitution reaction to prepare the compound shown in formula (VI);

[0169] 。

[0170] In some of these examples, in step S30, the molar ratio of the compound shown in formula (VII), the compound shown in formula (VIII), n-butyllithium, and SnCl2·2H2O is 1:2.3~3.5:1.1~1.3:5~10.

[0171] Furthermore, step S30 includes the following steps:

[0172] Under the protection of an inert gas, the compound shown in formula (VIII) is added to a three-necked flask, then THF is added, and the mixture is cooled to 0 °C and stirred. Optionally, the stirring time is 10 min~20 min; then n-butyllithium is slowly added dropwise to the reaction system, and then the mixture is heated to 50 °C~60 °C and stirred for reaction. Optionally, the stirring reaction time is 30 min~60 min; then the compound shown in formula (VII) is added to the reaction system and stirred for reaction. Optionally, the stirring reaction time is 1 h~3 h; then it is cooled to room temperature, and SnCl2·2H2O is added to the reaction system and stirred at room temperature for reaction. Optionally, the stirring reaction time is 2 h~3 h.

[0173] Furthermore, in step S30, it also includes a post-treatment step: after the reaction is completed, the mixture is introduced into ice water, extracted with ether, washed successively with saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate, and the crude product is purified by silica gel column chromatography after removing the excess mixed solvent by a rotary evaporator to obtain the compound shown in formula (VI).

[0174] In some of these examples, the preparation of the compound shown in formula (IV-1) includes step S40:

[0175] The compound shown in formula (IX) and triethyl phosphite are mixed for a substitution reaction to prepare the compound shown in formula (IV-1);

[0176]

[0177] Wherein, Z is a halogen atom.

[0178] In some of these examples, in step S40, the molar ratio of the compound shown in formula (IX) to triethyl phosphite is 1:25~50.

[0179] In some of these examples, in step S40, the temperature of the substitution reaction is 140°C to 160°C. Further, the time of the substitution reaction is 12 h to 16 h.

[0180] It can be understood that the compounds shown in formula (IV-1) and the compounds shown in formula (IV-2) can be prepared by the same preparation method, only replacing the compound shown in formula (IX) as the raw material with the compound shown in formula (IX-1):

[0181] 。

[0182] The raw material cost of the compound shown in formula (I) is low, the preparation process is simple, and it is suitable for industrial production.

[0183] In some of these examples, in the preparation method of the solar cell, the method for preparing the hole transport layer includes a solution method; further, the solution method includes a solution spin coating method.

[0184] In some of these examples, in the preparation method of the solar cell, preparing the hole transport layer on the first electrode includes the following steps:

[0185] Dissolve the compound shown in formula (I) in an organic solvent to obtain a mixed solution;

[0186] Spin coat the mixed solution onto the first electrode and anneal.

[0187] Optionally, the organic solvent includes at least one of dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane.

[0188] It can be understood that the compound shown in formula (I) has good solubility in dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane.

[0189] Optionally, the concentration of the compound shown in formula (I) in the mixed solution is 3 mg / mL to 15 mg / mL.

[0190] Optionally, the rotation speed of the spin coating is 4000 rpm to 5000 rpm.

[0191] Optionally, the annealing temperature is 90°C to 110°C.

[0192] In some of these examples, in the preparation method of the solar cell, before preparing the second electrode, it further includes the step of preparing an electron transport layer on the side of the perovskite light-absorbing layer away from the hole transport layer.

[0193] It can be understood that this application does not limit the methods for preparing the perovskite light-absorbing layer and the electron transport layer, including but not limited to the solution method; nor does it limit the preparation method of the second electrode, including but not limited to evaporation coating.

[0194] In some of these examples, in the method for preparing a solar cell, the following steps are included:

[0195] (1) Cleaning: The transparent conductive electrode TCO is ultrasonically cleaned successively with water, acetone, and ethanol. Optionally, the cleaning time is 10 min to 20 min; then the solvent remaining on the surface of the transparent conductive electrode is blown dry using an N2 gas gun, and then it is treated in an ultraviolet-ozone (UV-ozone) cleaner. Optionally, the treatment is 30 min to 60 min; subsequently, the transparent conductive electrode TCO is transferred to a nitrogen glove box;

[0196] (2) Preparation of the hole transport layer: The compound shown in formula (I) is dissolved in an organic solvent. Optionally, the organic solvent includes chlorobenzene; the prepared mixed solution is dropped onto the transparent conductive electrode TCO and spin-coated. Optionally, the spin-coating time is 20 s to 30 s; then it is annealed at 90°C to 110°C. Optionally, the annealing time is 10 min to 20 min;

[0197] (3) Preparation of the perovskite light-absorbing layer: The obtained TCO / hole transport layer is cooled to room temperature and preheated at 130°C to 140°C. Optionally, the preheating time is 3 min to 10 min; the perovskite precursor solution is disposed on the surface of the hole transport layer away from ITO and spin-coated. Optionally, the spin-coating time is 20 s to 30 s; then it is annealed at 90°C to 100°C. Optionally, the annealing time is 10 min to 15 min to prepare the perovskite light-absorbing layer. Optionally, the thickness of the perovskite light-absorbing layer is 500 nm to 1000 nm; wherein the perovskite precursor solution includes 3-halobenzylammonium iodide, methylammonium chloride, and lead iodide; 3-halobenzylammonium iodide is selected from 3-bromobenzylammonium iodide and / or 3-chlorobenzylammonium iodide; the solvent of the perovskite precursor solution includes at least one of but not limited to DMF and DMSO;

[0198] (4) Preparation of the electron transport layer: The obtained TCO / hole transport layer / perovskite light-absorbing layer is cooled to room temperature, and the electron transport solution is disposed on the surface of the perovskite light-absorbing layer away from the hole transport layer and spin-coated to prepare the electron transport layer; optionally, the electron transport material in the electron transport solution includes PC61BM; optionally, the spin-coating time is 40 s to 50 s; optionally, the thickness of the electron transport layer is 100 nm to 500 nm;

[0199] (5) Preparation of the electrode: The above substrate is placed in a vacuum evaporation chamber, and a metal is evaporated onto the electron transport layer; optionally, the metal includes Cr and Au; further, the thickness of Cr is 6 nm to 10 nm, and the thickness of Au is 80 nm to 100 nm to obtain a reverse-type quasi-two-dimensional perovskite solar cell.

[0200] One embodiment of the present application provides a tandem cell, including the above-mentioned solar cell or a solar cell prepared by the above-mentioned method for preparing a solar cell.

[0201] It can be understood that the tandem cell includes, but is not limited to, a two-terminal tandem cell, a three-terminal tandem cell, and a four-terminal tandem cell. Further, the tandem cell includes, but is not limited to, a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin-film cell. The thin-film cell includes, but is not limited to, a perovskite solar thin-film cell, a copper indium selenide solar thin-film cell, a gallium arsenide solar thin-film cell, and a cadmium sulfide solar thin-film cell; the crystalline silicon cell includes, but is not limited to, a PERC cell (passivated emitter and rear cell), an IBC cell (interdigitated back contact cell), a TOPCon cell (tunnel oxide passivated contact cell), an HJT cell (heterojunction cell), and an HBC cell (back contact heterojunction cell).

[0202] One embodiment of the present application provides a photovoltaic module, including the above-mentioned provided solar cell, a solar cell prepared by the above-mentioned provided method for preparing a solar cell, or the above-mentioned provided tandem cell.

[0203] In some examples, the photovoltaic module includes:

[0204] A string of cells, electrically connected by a plurality of the above-mentioned solar cells or perovskite cells prepared by the above-mentioned method for preparing a solar cell, or electrically connected by a plurality of the above-mentioned tandem cells;

[0205] An encapsulant film, used to cover the surface of the string of cells; and

[0206] A cover plate, used to cover the surface of the encapsulant film facing away from the string of cells.

[0207] It can be understood that the solar cell or the tandem cell is electrically connected in the form of a whole piece or multiple sub-pieces to form a plurality of strings of cells, and the plurality of strings of cells are electrically connected in series and / or in parallel. Further, the solar cell or the tandem cell can be a whole-piece cell or a sliced cell, and the sliced cell refers to a cell formed by cutting a complete whole-piece cell through a cutting process.

[0208] In some examples, the plurality of strings of cells can be electrically connected through a conductive strip.

[0209] In some of these examples, the encapsulation film includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the front and back sides of the battery, and the second encapsulation layer covers the other of the front and back sides of the battery. Further, the first encapsulation layer and the second encapsulation layer can each independently include at least one of organic encapsulation films such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyoctene copolymer (POE) film, and polyethylene terephthalate (PET) film.

[0210] In some of these examples, the cover plate can be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate.

[0211] It can be understood that photovoltaic modules are widely used, such as in the power station field and building integrated photovoltaic (BIPV). In the power station field, they can be laid on a large scale in centralized power stations or distributed power stations for power generation. Building Integrated Photovoltaic (BIPV) is a technology that integrates photovoltaic power generation products into buildings. By designing solar panels into various building decoration materials to replace traditional decoration materials such as glass curtain walls or roof tiles, for example, photovoltaic tile roofs can provide functions such as protecting against wind and rain, and at the same time can serve as a solar power generation system to provide environmentally friendly electricity. Photovoltaic tiles are an important part of rooftop power stations and are used to convert the received solar energy into electrical energy to meet the electrical energy needs of daily production and life.

[0212] An embodiment of the present application provides an electrical device including the above-mentioned photovoltaic module.

[0213] It can be understood that the electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a stationary or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, for example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, and a power planer, etc. The embodiments of the present application do not impose special restrictions on the above-mentioned electrical devices.

[0214] The following further describes the present application in detail in conjunction with specific embodiments, but the embodiments of the present application are not limited thereto.

[0215] Example 1

[0216] Synthesis of BT-Cz

[0217] (1) Under the protection of inert gas, compound 1, tetrabutylammonium bromide, and KOH were dissolved in 1,2-dibromobutane for a substitution reaction. The reaction temperature was 65 - 70 °C, and the reaction time was 12 - 24 h. After the reaction, the reaction was quenched with water, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. The crude product was separated and purified by silica gel column chromatography and dried in vacuo to obtain compound 2. The molar ratio of compound 1, tetrabutylammonium bromide, KOH, and 1,2-dibromobutane was 1:0.1 - 0.2:5 - 10:50 - 150. The reaction equation is as follows:

[0218]

[0219] (2) Under the protection of inert gas, compound 2 and triethyl phosphite were reacted. The reaction temperature was 140 - 160 °C, and the reaction time was 12 - 16 h. After cooling to room temperature, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure to obtain the crude product compound 3. The molar ratio of compound 2 and triethyl phosphite was 1:25 - 50. The reaction equation is as follows:

[0220]

[0221] (3) Under the protection of inert gas, compound 5 was added to a 500 mL three-necked flask, and then 30 mL of dry THF was added. After cooling to 0 °C and stirring for 10 - 20 min, n-butyllithium was very slowly added dropwise to the reaction system. Then the mixture was heated to 50 °C and stirred for 30 minutes. Then compound 4 was added to the reaction system and stirred for 1 - 2 hours. After cooling to room temperature, the SnCl2·2H2O solution was added to the reaction system and stirred at room temperature for 2 - 3 hours. After the reaction, the mixture was poured into ice water and extracted three times with ether, washed successively with saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate. After the crude product was evaporated to remove the excess mixed solvent by a rotary evaporator, it was purified by silica gel column chromatography to obtain compound 6. The molar ratio of compound 4, compound 5, n-butyllithium, and SnCl2·2H2O was 1:2.3 - 3.5:1.1 - 1.3:5 - 10. The reaction equation is as follows:

[0222]

[0223] (4) Under the protection of inert gas, compound 6 was added into a 500 mL three-necked flask, and then 30 mL of dry THF was added. The mixture was cooled to -78 °C and stirred for 10 - 20 min. Then, n-butyllithium was slowly added dropwise. The reaction was carried out at -78 °C for 1 hour and at room temperature for 40 minutes. It was placed at -78 °C again, and trimethyltin chloride was added. After stirring at low temperature for 10 - 20 minutes, the reaction was carried out at room temperature for one hour. 100 mL of deionized water was added to terminate the reaction. The mixture was extracted three times with ether, washed successively with saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate. After the crude product was evaporated by a rotary evaporator to remove the excess mixed solvent, it was purified by silica gel column chromatography to obtain compound 7. The molar ratio of compound 6, n-butyllithium, and trimethyltin chloride was 1:1.2 - 3:2.2 - 4. The reaction formula is as follows:

[0224]

[0225] (5) Under the protection of inert gas, compound 7, compound 3, Pd(PPh3)4 and 30 mL of toluene were successively added into a dry two-necked flask. The reaction was carried out at 110 - 120 °C in the dark for 36 - 50 hours. After cooling to room temperature, the crude product was evaporated by a rotary evaporator to remove the excess mixed solvent. The crude product was recrystallized several times to obtain compound 8. The molar ratio of compound 7, compound 3, and Pd(PPh3)4 was 1:2.2 - 3:0.05 - 0.15. The reaction formula is as follows:

[0226]

[0227] (6) Under the protection of inert gas, compound 8 was dissolved in 1,4-dioxane at 25 °C, and trimethylsilyl bromide was added dropwise, then stirred overnight. The solvent was removed by a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol at room temperature, and then deionized water was added dropwise until the mixture became opaque, and then stirred for 10 - 16 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in THF and reprecipitated in acetone, and then filtered to obtain the final compound material BT-Cz. The 1H NMR spectrum of BT-Cz is as Figure 2 shown. The molar ratio of compound 8 and trimethylsilyl bromide was 1:8 - 15. The reaction formula is as follows:

[0228]

[0229] Example 2

[0230] Synthesis of BT-Ac

[0231] (1) Under the protection of inert gas, compound 9, tetrabutylammonium bromide, and KOH were dissolved in 1,2-dibromobutane for a substitution reaction. The reaction temperature was 65 - 70 °C, and the reaction time was 12 - 24 h. After the reaction, the reaction was quenched with water, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. The crude product was separated and purified by silica gel column chromatography and dried in vacuo to obtain compound 10. The molar ratio of compound 9, tetrabutylammonium bromide, KOH, and 1,2-dibromobutane was 1:0.1 - 0.2:5 - 10:50 - 150. The reaction formula is as follows:

[0232]

[0233] (2) Under the protection of inert gas, compound 10 and triethyl phosphite were reacted. The reaction temperature was 140 - 160 °C, and the reaction time was 12 - 16 h. After cooling to room temperature, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure to obtain the crude product compound 11. The molar ratio of compound 10 and triethyl phosphite was 1:25 - 50. The reaction formula is as follows:

[0234]

[0235] (3) Under the protection of inert gas, compound 5 was added to a 500 mL three-necked flask, and then 30 mL of dry THF was added. The mixture was cooled to 0 °C and stirred for 10 - 20 min. n-Butyllithium was very slowly added dropwise to the reaction system, and then the mixture was heated to 50 °C and stirred for 30 minutes. Then compound 4 was added to the reaction system and stirred for 1 - 2 hours. After cooling to room temperature, an SnCl2·2H2O solution was added to the reaction system and stirred at room temperature for 2 - 3 hours. After the reaction, the mixture was poured into ice water and extracted three times with diethyl ether, washed successively with saturated sodium chloride aqueous solution, and dried over anhydrous magnesium sulfate. After the crude product was evaporated to remove the excess mixed solvent by a rotary evaporator, it was purified by silica gel column chromatography to obtain compound 6. The molar ratio of compound 4, compound 5, n-butyllithium, and SnCl2·2H2O was 1:2.3 - 3.5:1.1 - 1.3:5 - 10. The reaction formula is shown in Example 1.

[0236] (4) Under the protection of inert gas, compound 6 was added to a 500 mL three-necked flask, and then 30 mL of dry THF was added. The mixture was cooled to -78 °C and stirred for 10 - 20 min. Then, n-butyllithium was slowly added dropwise. The reaction was carried out at -78 °C for 1 hour and at room temperature for 40 minutes. It was placed at -78 °C again, and trimethyltin chloride was added. After stirring at low temperature for 10 - 20 minutes, the reaction was carried out at room temperature for one hour. 100 mL of deionized water was added to terminate the reaction. The mixture was extracted with ether three times, washed successively with saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate. After the crude product was concentrated by a rotary evaporator to remove the excess mixed solvent, it was purified by silica gel column chromatography to obtain compound 7. The molar ratio of compound 6, n-butyllithium, and trimethyltin chloride was 1:1.2 - 3:2.2 - 4. The reaction formula is shown in Example 1.

[0237] (5) Under the protection of inert gas, compound 7, compound 11, Pd(PPh3)4, and 30 mL of toluene were successively added to a dry two-necked flask. The reaction was carried out at 110 - 120 °C in the dark for 36 - 50 hours. After cooling to room temperature, the crude product was concentrated by a rotary evaporator to remove the excess mixed solvent. The crude product was recrystallized several times to obtain compound 12. The molar ratio of compound 7, compound 11, and Pd(PPh3)4 was 1:2.2 - 3:0.05 - 0.15. The reaction formula is as follows:

[0238]

[0239] (6) Under the protection of inert gas, compound 12 was dissolved in 1,4-dioxane at 25 °C, and trimethylsilyl bromide was added dropwise, and then stirred overnight. The solvent was removed by a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol at room temperature, and then deionized water was added dropwise until the mixture became opaque, and then stirred for 10 - 16 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in THF and reprecipitated in acetone, and the final compound material BT-Ac was obtained by filtration. The 1H NMR spectrum of BT-Ac is as Figure 3 shown. The molar ratio of compound 12 and trimethylsilyl bromide was 1:8 - 15. The reaction formula is as follows:

[0240]

[0241] Example 3

[0242] Synthesis of BT-POZ

[0243] (1) Under the protection of inert gas, compound 13, tetrabutylammonium bromide, and KOH were dissolved in 1,2-dibromobutane for a substitution reaction. The reaction temperature was 65 - 70 °C, and the reaction time was 12 - 24 h. After the reaction, the reaction was quenched with water, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure. The crude product was separated and purified by silica gel column chromatography and dried in vacuo to obtain compound 14. The molar ratio of compound 13, tetrabutylammonium bromide, KOH, and 1,2-dibromobutane was 1:0.1 - 0.2:5 - 10:50 - 150. The reaction equation is as follows:

[0244]

[0245] (2) Under the protection of inert gas, compound 14 and triethyl phosphite were reacted. The reaction temperature was 140 - 160 °C, and the reaction time was 12 - 16 h. After cooling to room temperature, the mixture was extracted with DCM, the organic phase was dried over anhydrous Mg2SO4, filtered, and distilled under reduced pressure to obtain the crude product compound 15. The molar ratio of compound 14 and triethyl phosphite was 1:25 - 50. The reaction equation is as follows:

[0246]

[0247] (3) Under the protection of inert gas, compound 5 was added to a 500 mL three-necked flask, and then 30 mL of dry THF was added. The mixture was cooled to 0 °C and stirred for 10 - 20 min. n-Butyllithium was very slowly added dropwise to the reaction system, and then the mixture was heated to 50 °C and stirred for 30 minutes. Then compound 4 was added to the reaction system and stirred for 1 - 2 hours. After cooling to room temperature, an SnCl2·2H2O solution was added to the reaction system and stirred at room temperature for 2 - 3 hours. After the reaction, the mixture was poured into ice water and extracted three times with diethyl ether. It was successively washed with saturated sodium chloride aqueous solution and dried over anhydrous magnesium sulfate. After the crude product was evaporated by a rotary evaporator to remove the excess mixed solvent, it was purified by silica gel column chromatography to obtain compound 6. The molar ratio of compound 4, compound 5, n-butyllithium, and SnCl2·2H2O was 1:2.3 - 3.5:1.1 - 1.3:5 - 10. The reaction equation can be seen in Example 1.

[0248] (4) Under the protection of inert gas, compound 6 was added into a 500 mL three-necked flask, and then 30 mL of dry THF was added. The mixture was cooled to -78 °C and stirred for 10 - 20 min, and then n-butyllithium was slowly added dropwise. The reaction was carried out at -78 °C for 1 hour and at room temperature for 40 minutes. Then, it was placed at -78 °C again, and trimethyltin chloride was added. After stirring at low temperature for 10 - 20 minutes, the reaction was carried out at room temperature for one hour, and 100 mL of deionized water was added to terminate the reaction. The mixture was extracted with ether three times, washed successively with saturated sodium chloride aqueous solution, dried over anhydrous magnesium sulfate. After the crude product was concentrated by a rotary evaporator to remove the excess mixed solvent, it was purified by silica gel column chromatography to obtain compound 7. The molar ratio of compound 6, n-butyllithium, and trimethyltin chloride was 1:1.2 - 3:2.2 - 4. The reaction formula is shown in Example 1.

[0249] (5) Under the protection of inert gas, compound 7, compound 15, Pd(PPh3)4 and 30 mL of toluene were successively added into a dry two-necked flask. The reaction was carried out at 110 - 120 °C in the dark for 36 - 50 hours. After cooling to room temperature, the crude product was concentrated by a rotary evaporator to remove the excess mixed solvent. The crude product was recrystallized several times to obtain compound 16. The molar ratio of compound 7, compound 15, and Pd(PPh3)4 was 1:2.2 - 3:0.05 - 0.15. The reaction formula is as follows:

[0250]

[0251] (6) Under the protection of inert gas, compound 16 was dissolved in 1,4-dioxane at 25 °C, and trimethylsilyl bromide was added dropwise, and then stirred overnight. The solvent was removed by a rotary evaporator to obtain a solid powder. The solid powder was dissolved in methanol at room temperature, and then deionized water was added dropwise until the mixture became opaque, and then stirred for 10 - 16 hours. The crude product was collected by filtration and washed with deionized water. The crude product was dissolved in THF and reprecipitated in acetone, and the final compound material BT-POZ was obtained by filtration. The 1H NMR spectrum of BT-POZ is shown as Figure 4 shown. The molar ratio of compound 16 and trimethylsilyl bromide was 1:8 - 15. The reaction formula is as follows:

[0252]

[0253] Comparative Example 1

[0254] It was basically the same as Example 1, except that step (2) in Example 1 was omitted, compound 3 in step (5) of Example 1 was replaced with an equimolar amount of compound 2, and step (6) in Example 1 was omitted to obtain compound 17; the reaction formula of step (5) in Comparative Example 1 is as follows:

[0255]

[0256] The perovskite solar cells were fabricated using the compounds prepared in each example and comparative example as hole transport materials:

[0257] 1. Pretreatment of ITO glass: Mark the non-conductive surface without ITO coating for distinction. Ultrasonically clean the conductive glass with deionized water, acetone, and absolute ethanol for about 10 min in sequence; then use an N2 spray gun to remove the residual solvent on the ITO glass surface, and finally treat the wafer in a UV-ozone cleaner for 30 min, and immediately transfer it to the glove box for standby.

[0258] 2. Preparation of HTL: Weigh 5 - 15 mg of the HTM to be tested, use chlorobenzene as the solvent, prepare a solution containing the polymer hole transport material, and stir overnight. When preparing the hole transport layer, use a pipette to aspirate 30 mL of the solution, evenly drop it onto the treated ITO glass, spin-coat it with a spin coater for 20 s, and finally anneal it on a heating stage at 100 °C for 10 min to form a hole transport layer of about 20 nm, and cool it to room temperature.

[0259] 3. Preparation of perovskite layer: Preparation of perovskite precursor solution: Dissolve 3-fluoro-benzylammonium iodide (3FBAI), ammonium chloride (MACl), and lead iodide (PbI2) in DMF in a ratio of 2.2:3.5:4, and stir overnight. When preparing the perovskite absorption layer, first filter the precursor solution, and preheat the previous hole transport layer substrate at 140 °C for 3 min. Use a pipette to aspirate 50 mL of the precursor solution, quickly drop it onto the substrate containing HTM, spin-coat it with a spin coater for 20 s, and finally anneal it on a heating stage at 90 °C for 15 min to form a perovskite layer of about 500 nm, and cool it to room temperature.

[0260] 4. Preparation of ETL: Dissolve PC61BM in chlorobenzene and stir overnight. Use a pipette to aspirate 30 mL of the solution, evenly coat it on the perovskite layer, spin-coat it with a spin coater for 40 s, and then anneal it on a heating stage at 70 °C for 10 min to complete the preparation of an ETL of about 100 nm. Transfer the wafer to the evaporation instrument for standby.

[0261] 5. Preparation of metal electrode: Place the prepared ITO / HTL / Quasi-2D perovskite / ETL substrate into the mask plate, and use a thermal evaporation system to evaporate Cr (about 6 nm) and Cu (about 80 nm) onto the device respectively to complete the fabrication of the solar cell. Finally, define the area overlapping with the electrode on the ITO substrate as the effective area, which is 0.03 cm 2 。

[0262] The space-charge-limited current method was used to measure the hole mobility. A single-hole device of ITO / PEDOT:PSS / HTMs to be measured / MoO3 / Ag was fabricated, and the film thickness of each layer was determined by a step profiler. The J-V characteristic curve of the device was obtained by a Keithley 2450 Source-Measure instrument under dark conditions. Nonlinear fitting analysis was performed on the curve to obtain the carrier mobility of the sample. The test results are shown in Table 1.

[0263] Table 1

[0264]

[0265] As can be seen from Table 1, the energy levels of BT-Cz, BT-Ac, and BT-POZ match those of the Quasi-2D perovskite material, enabling the formation of good Ohmic contacts, which is conducive to hole transport. Moreover, compared with Comparative Example 1, the hole mobilities of BT-Cz, BT-Ac, and BT-POZ are higher, indicating a stronger ability to extract and transport holes.

[0266] Film-forming performance: AFM was used to study the crystal growth of Quasi-2D perovskite films on different polymer HTMs. The Quasi-2D perovskite films based on BT-Cz, BT-Ac, and BT-POZ exhibited relatively low RMS roughness values of 12.8 nm, 13.6 nm, and 14.7 nm, respectively. BT-Cz, BT-Ac, and BT-POZ as HTM substrates are beneficial for the diffusion and growth of Quasi-2D perovskite, resulting in dense, uniform, and smooth perovskite films.

[0267] Under AM 1.5G illumination conditions, the J-V (Current density−Voltage) curves of the best devices measured by forward and reverse scans at a speed of 0.02V s -1 are shown as follows. The abscissa is Voltage (open-circuit voltage, unit: V), and the ordinate is Current density (short-circuit current, unit: mA / cm Figure 5 . The detailed open-circuit voltage (Voc), short-circuit current (Jsc), fill factor (FF), and power conversion efficiency (PCE) are shown in Table 2. 2 ).

[0268] Table 2

[0269]

[0270] As can be seen from Table 2, compared with the perovskite solar cells prepared using Compound 17 (without a phosphate group) obtained in Comparative Example 1 as the hole transport material, the perovskite cells prepared using BT-Cz, BT-Ac, and BT-POZ (using benzodithiophene as the molecular core and carbazole phosphate, acridine phosphate, or phenoxazine phosphate groups as the end groups, containing phosphate groups) obtained in the examples have better photovoltaic performance.

[0271] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0272] The above-described embodiments merely represent several implementation manners of the present application, which are convenient for understanding the technical solutions of the present application specifically and in detail, but should not be construed as a limitation on the protection scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning, or limited experiments based on the technical solutions provided in the present application are all within the protection scope of the appended claims of the present application. Therefore, the protection scope of the patent of the present application should be subject to the content of the appended claims, and the specification can be used to explain the content of the claims.

Claims

1. A solar cell, characterized in that: The invention comprises a first electrode, a hole transport layer, a perovskite light absorbing layer and a second electrode, wherein the hole transport layer is located between the first electrode and the perovskite light absorbing layer, the perovskite light absorbing layer is located between the hole transport layer and the second electrode, and the hole transport layer comprises a compound represented by formula (I): Wherein, R1 is selected from one of the structures represented by formula (II-1) and formula (II-2): L1 is selected from and One of; L2 is selected from one of C1~C6 alkylene groups; R2 is selected from C1~C 10 One of the alkyl groups; R3~R4 are independently selected from hydrogen, substituted or unsubstituted C1~C 10 Alkyl, substituted or unsubstituted C1~C 10 Alkoxy, substituted or unsubstituted C1~C 10 Alkylthio, halogen, trifluoromethyl, hydroxyl, mercapto, cyano, amino and substituted or unsubstituted C6~C 18 One of the aromatic groups; Each occurrence of m is independently selected from an integer of 1 to 3; each occurrence of n is independently selected from an integer of 1 to 4; X is selected from a single bond, an oxygen atom, C(R5)2 and NR6, and R5-R6 are independently selected from hydrogen and substituted or unsubstituted C1-C 10 One of the alkyl groups; The substituted substituents are independently selected from one of C1-C4 alkyl, amino, halogen, nitro, hydroxyl, mercapto, carboxyl and cyano.

2. The solar cell according to claim 1, wherein: In the compound represented by formula (I), L1 is selected from ; and / or, L2 is selected from one of C2 to C4 alkylene groups; optionally, L2 is selected from one of propylene and butylene groups; And / or, R2 is selected from one of C4~C8 alkyl groups; optionally, R2 is selected from one of n-pentyl, n-hexyl and n-heptyl; and / or, R3 to R4 are independently selected from one of hydrogen, C1 to C4 alkyl, C1 to C4 alkoxy, C1 to C4 alkylthio, halogen, trifluoromethyl, hydroxyl, mercapto, cyano and amino; optionally, R3 to R4 are all hydrogen; And / or, X is selected from a single bond, an oxygen atom and C(R5)2, R5 is selected from hydrogen and a substituted or unsubstituted C1~C4 alkyl group; optionally, R5 is a methyl group.

3. The solar cell according to claim 2, characterized in that The hole transport layer includes a compound represented by formula (I-1): 。 4. The solar cell according to claim 2, wherein: R1 is selected from one of the structures shown in formula (II-1-a) to formula (II-1-c): 。 5. The solar cell according to claim 1, wherein: The hole transport layer includes at least one of BT-Cz, BT-Ac and BT-POZ: 。 6. The solar cell according to any one of claims 1 to 5, characterized in that: The perovskite light-absorbing layer includes ABX3, A is a monovalent cation, B is a divalent metal cation, and X is a halogen anion; optionally, the monovalent cation includes at least one of cesium ion, methylamine ion, ethylamine ion, formamidine ion, benzylamine ion and phenylethylamine ion, the halogen anion includes at least one of lead ion, tin ion and copper ion, and the halogen anion includes at least one of bromide ion, chloride ion and iodide ion; And / or, the solar cell further comprises an electron transport layer, wherein the electron transport layer is located between the perovskite light absorbing layer and the second electrode; optionally, the electron transport layer comprises at least one of metal oxides, fullerenes and derivatives thereof.

7. A method for preparing a solar cell, characterized in that: The following steps are involved: preparing a hole transport layer on the first electrode; Preparing a perovskite light absorbing layer on a side of the hole transport layer away from the first electrode; Prepare a second electrode on a side of the perovskite light absorbing layer away from the hole transport layer; The hole transport layer comprises a compound represented by formula (I): Wherein, R1 is selected from one of the structures represented by formula (II-1) and formula (II-2): L1 is selected from and One of; L2 is selected from one of C1~C6 alkylene groups; R2 is selected from C1~C 10 One of the alkyl groups; R3~R4 are independently selected from hydrogen, substituted or unsubstituted C1~C 10 Alkyl, substituted or unsubstituted C1~C 10 Alkoxy, substituted or unsubstituted C1~C 10 Alkylthio, halogen, trifluoromethyl, hydroxyl, mercapto, cyano, amino and substituted or unsubstituted C6~C 18 One of the aromatic groups; Each occurrence of m is independently selected from an integer of 1 to 3; each occurrence of n is independently selected from an integer of 1 to 4; X is selected from a single bond, an oxygen atom, C(R5)2 and NR6, and R5-R6 are independently selected from hydrogen and substituted or unsubstituted C1-C 10 One of the alkyl groups; The substituted substituents are independently selected from one of C1-C4 alkyl, amino, halogen, nitro, hydroxyl, mercapto, carboxyl and cyano.

8. The method for preparing a solar cell according to claim 7, characterized in that: The preparation of the compound represented by formula (I) comprises the following steps: The compound represented by formula (I) is prepared by mixing one of the compound represented by formula (IV-1) and the compound represented by formula (IV-2) with the compound represented by formula (III) and sequentially performing Stille coupling reaction and hydrolysis reaction; Wherein, Y is a halogen atom.

9. A laminated battery, characterized in that: A solar cell comprising the solar cell according to any one of claims 1 to 6 or a solar cell prepared by the method for preparing a solar cell according to any one of claims 7 to 8.

10. A photovoltaic module, characterized in that: It includes the solar cell as described in any one of claims 1 to 6, the solar cell prepared by the method for preparing a solar cell as described in any one of claims 7 to 8, or the stacked cell as described in claim 9.

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