Tetrathienopyrrole compound as well as preparation method and application thereof

Abstract

The invention relates to a tetrathienopyrrole compound as well as a preparation method and application thereof. The tetrathienopyrrole compound is a compound represented by a formula (I): # imgabs0 #, and the tetrathienopyrrole compound is a compound represented by a formula (II). Wherein each R is independently selected from H, a C1-C5 alkyl group, a C1-C5 alkoxy group or a C1-C5 alkylthio group. The tetrathienopyrrole compound takes tetrathienopyrrole as an acceptor unit, and triphenylamine is introduced to two ends of the acceptor unit through thiophene groups to serve as donor units, so that the compound has the advantages of good planarity, high conjugation degree, high hole mobility, energy level matched with perovskite, energy level adjustability and the like; good photoelectric conversion efficiency can be obtained when the material is applied to trans-perovskite solar cells as an undoped hole transport material.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and particularly to a tetrathienopyrrole compound, a preparation method thereof, and an application thereof. Background Art

[0002] In recent years, perovskite solar cells, as a rapidly developing third-generation solar cell technology, have attracted much attention. Perovskite solar cells have many advantages such as low exciton binding energy, long carrier diffusion length, low manufacturing cost, and simple process. In the structure of perovskite solar cells, the hole transport layer (HTL) has a significant impact on the photoelectric conversion efficiency and performance stability of the device. While extracting and transporting holes, the hole transport layer also affects the crystallization state and film microstructure of the perovskite layer. In addition, the hole transport layer can also play a role in protecting the perovskite active layer from external factors such as water and oxygen.

[0003] At present, hole transport materials are mainly divided into three categories: inorganic hole transport materials, organic small molecule hole transport materials, and polymer hole transport materials. Among them, inorganic hole transport materials have good conductivity, but their solution processability is poor, and the improvement of performance is usually limited by surface defects. It is very difficult to have a fixed molecular weight distribution during the synthesis of polymer hole transport materials, which brings great challenges to the repeatability and stability of the devices. Organic small molecule hole transport materials have the characteristics of definite molecular weight, good reproducibility, excellent film-forming property, etc., avoiding the poor solution processability of inorganic hole transport materials and the poor reproducibility of polymer hole transport materials.

[0004] The hole mobility of organic small molecule hole transport materials needs to be improved. When applied to the hole transport layer of perovskite solar cells, a P-type dopant usually needs to be added to improve the hole mobility, but the use of the dopant also causes problems such as high cost and poor stability. Therefore, it is necessary to find organic small molecule hole transport materials with high hole mobility. Summary of the Invention

[0005] Based on this, the present invention provides a tetrathienopyrrole compound, a preparation method thereof, and an application thereof. This compound has advantages such as good planarity, high conjugation degree, high hole mobility, energy levels matching with perovskite and adjustable energy levels.

[0006] The first aspect of the present invention is to provide a tetrathienopyrrole compound, and the solution is as follows:

[0007] A tetrathienopyrrole compound has a molecular structure shown in formula (I):

[0008] ;

[0009] In formula (I), each R is independently selected from H, C1-C5 alkyl, C1-C5 alkoxy, or C1-C5 alkylthio.

[0010] In some embodiments, each R is independently selected from C1-C3 alkoxy or C1-C3 alkylthio.

[0011] In some embodiments, each R is independently selected from methoxy or methylthio.

[0012] In some embodiments, the tetrathienopyrrole compound is:

[0013] or .

[0014] The second aspect of the present invention is to provide a method for preparing the above-mentioned tetrathienopyrrole compound, and the scheme is as follows:

[0015] A method for preparing a tetrathienopyrrole compound, comprising the following steps:

[0016] Subject compound 1 and compound 2 to a first Suzuki coupling reaction to obtain compound 3;

[0017] ; ; ;

[0018] In compound 1, X is selected from halogen;

[0019] Subject compound 3 and compound 4 to a second Suzuki coupling reaction to obtain compound 5;

[0020] ; ;

[0021] In compound 4, each X is independently selected from halogen;

[0022] Subject compound 5 and compound 2 to a third Suzuki coupling reaction to obtain compound 6;

[0023] ;

[0024] Subject compound 7 and compound 8 to a substitution reaction to obtain compound 9;

[0025] ; ; ;

[0026] In formula (7), each X is independently selected from halogen;

[0027] Subject the compound 9 to a halogenation reaction to obtain compound 10;

[0028] ;

[0029] In the compound 10, each X is independently selected from a halogen;

[0030] Subject the compound 10 and the compound 6 to a fourth Suzuki coupling reaction to obtain the tetrathienopyrrole compound.

[0031] In some embodiments, the first Suzuki coupling reaction comprises the following steps:

[0032] Dissolve the compound 1 in a first solvent, add a first catalyst, react at -85°C to -75°C for 1 h to 2 h, add the compound 2, react at -85°C to -75°C for 1 h to 2 h, and then react at room temperature for 10 h to 16 h.

[0033] In some embodiments, in the first Suzuki coupling reaction, the molar ratio of the compound 1 to the compound 2 is 1:(1.2 to 1.5).

[0034] In some embodiments, (3) the first catalyst used in the first Suzuki coupling reaction comprises n-butyllithium.

[0035] In some embodiments, the second Suzuki coupling reaction comprises the following steps:

[0036] Mix and dissolve the compound 3, the compound 4, a first base agent, and a second catalyst in a second solvent, and react at 80°C to 90°C for 6 h to 12 h.

[0037] In some embodiments, in the second Suzuki coupling reaction, the molar ratio of the compound 3 to the compound 4 is 1:(2.2 to 3).

[0038] In some embodiments, the second catalyst used in the second Suzuki coupling reaction comprises tetrakis(triphenylphosphine)palladium.

[0039] In some embodiments, the third Suzuki coupling reaction comprises the following steps:

[0040] Dissolve the compound 5 in a third solvent, add a third catalyst, react at -85°C to -75°C for 1 h to 2 h, add the compound 2, react at -85°C to -75°C for 1 h to 2 h, and then react at room temperature for 10 h to 16 h.

[0041] In some of these embodiments, in the third Suzuki coupling reaction, the molar ratio of the compound 5 to the compound 2 is 1∶(1.2 to 1.5).

[0042] In some of these embodiments, the third catalyst used in the third Suzuki coupling reaction includes n-butyllithium.

[0043] In some of these embodiments, the substitution reaction includes the following steps:

[0044] The compound 7, the compound 8 and a fourth catalyst are mixed and dissolved in a fourth solvent, and the reaction is carried out at 110°C to 120°C for 12 h to 24 h.

[0045] In some of these embodiments, in the substitution reaction, the molar ratio of the compound 7 to the compound 8 is 1∶(2.2 to 2.5).

[0046] In some of these embodiments, the fourth catalyst used in the substitution reaction includes at least one of sodium tert-butoxide, Pd2(dba)3 and dppf.

[0047] In some of these embodiments, the halogenation reaction includes the following steps:

[0048] The compound 9 and a halogenating agent are mixed and dissolved in a fifth solvent, and the reaction is carried out at -2°C to 0°C for 3 h to 4 h.

[0049] In some of these embodiments, the halogenating agent used in the halogenation reaction includes N-bromosuccinimide.

[0050] In some of these embodiments, in the halogenation reaction, the molar ratio of the compound 9 to the halogenating agent is 1∶(2 to 3).

[0051] In some of these embodiments, the fourth Suzuki coupling reaction includes the following steps:

[0052] The compound 10, the compound 6, a second base agent and a sixth catalyst are mixed and dissolved in a sixth solvent, and the reaction is carried out at 80°C to 90°C for 6 h to 16 h.

[0053] In some of these embodiments, in the fourth Suzuki coupling reaction, the molar ratio of the compound 10 to the compound 6 is 1∶(2.2 to 2.5).

[0054] In some of these embodiments, the sixth catalyst used in the fourth Suzuki coupling reaction includes tetrakis(triphenylphosphine)palladium.

[0055] The third aspect of the present invention is to provide the application of the described tetrathienopyrrole compounds as hole transport materials.

[0056] The fourth aspect of the present invention is to provide a solar cell, and the solution is as follows:

[0057] A solar cell includes a transparent conductive substrate, a hole transport layer, a perovskite light absorption layer, and an electrode layer that are sequentially stacked. The hole transport layer contains the tetrathienopyrrole compound described in any of the above embodiments.

[0058] Compared with the traditional technology, the above tetrathienopyrrole compound has the following beneficial effects:

[0059] The above tetrathienopyrrole compound uses tetrathienopyrrole as the acceptor unit, and triphenylamine is introduced as the donor unit through thiophene groups at both ends of the acceptor unit. This compound has good solubility in solvents such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane, and has advantages such as good planarity, high conjugation degree, high hole mobility, energy levels matching with perovskite and adjustable energy levels. Using it as an undoped hole transport material in a reverse perovskite solar cell can obtain a high photoelectric conversion efficiency. Description of the Drawings

[0060] Figure 1 It is a schematic structural diagram of the solar cell according to an embodiment of the present invention;

[0061] Figure 2 It is a nuclear magnetic resonance hydrogen spectrum diagram of the tetrathienopyrrole compound TP-1 prepared in Example 1;

[0062] Figure 3 It is a nuclear magnetic resonance hydrogen spectrum diagram of the tetrathienopyrrole compound TP-2 prepared in Example 2;

[0063] Figure 4 It is a TGA curve diagram of the tetrathienopyrrole compounds TP-1 and TP-2.

[0064] Description of the Reference Numerals:

[0065] 100. Solar cell; 110. Transparent conductive substrate; 120. Hole transport layer; 130. Perovskite light absorption layer; 140. Electrode layer; 150. Electron transport layer. Detailed Embodiments

[0066] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific embodiments of the present invention with reference to the accompanying drawings. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein 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.

[0068] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the 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 thus should not be construed as limiting the present invention.

[0069] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0070] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral body; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] Unless otherwise stated or there is a contradiction, the terms or phrases used herein have the following meanings:

[0072] The term "alkyl" refers to a saturated hydrocarbon containing primary carbon atoms, or secondary carbon atoms, or tertiary carbon atoms, or quaternary carbon atoms, or a combination thereof. A phrase containing this term, for example, "C1-C5 alkyl" refers to an alkyl group containing 1 to 5 carbon atoms, which can be independently of each other C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl or C5 alkyl each time it appears. The alkyl group can be linear or branched. Suitable examples include but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(CH3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2).

[0073] The term "alkoxy" refers to a group having -O-alkyl, that is, the alkyl group as defined above is connected to the parent nucleus structure via an oxygen atom. A phrase containing this term, for example, "C1-C5 alkoxy" means that the alkyl part contains 1 to 5 carbon atoms, which can be independently of each other C1 alkoxy, C2 alkoxy, C3 alkoxy, C4 alkoxy or C5 alkoxy each time it appears. The alkoxy group can be linear or branched. Suitable examples include but are not limited to: methoxy (-O-CH3 or -OMe), ethoxy (-O-CH2CH3 or -OEt) and tert-butoxy (-O-C(CH3)3 or -OtBu).

[0074] The term "alkylthio" refers to a group having -S-alkyl, that is, the alkyl group as defined above is connected to the parent nucleus structure via a sulfur atom. A phrase containing this term, for example, "C1-C5 alkylthio" means that the alkyl part contains 1 to 5 carbon atoms, which can be independently of each other C1 alkylthio, C2 alkylthio, C3 alkylthio, C4 alkylthio or C5 alkylthio each time it appears. The alkoxy group can be linear or branched. Suitable examples include but are not limited to: methylthio (-S-CH3), ethylthio (-S-CH2CH3) and tert-butylthio (-S-C(CH3)3).

[0075] "Halogen" refers to F, Cl, Br or I.

[0076] The tetrathienopyrrole compound provided by the present invention has a molecular structure shown in formula (I):

[0077]

[0078] In formula (I), each R is independently selected from H, C1-C5 alkyl, C1-C5 alkoxy or C1-C5 alkylthio.

[0079] The above-mentioned tetrathienopyrrole compound uses tetrathienopyrrole as the acceptor unit, and triphenylamine is introduced as the donor unit through thiophene groups at both ends of the acceptor unit. This compound has good solubility in solvents such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, dichloromethane, etc., and has advantages such as good planarity, high conjugation degree, high hole mobility, energy levels matching with perovskite and adjustable energy levels. Using it as an undoped hole transport material in a perovskite solar cell can obtain a high photoelectric conversion efficiency.

[0080] In some examples, each R is independently selected from C1-C5 alkoxy or C1-C5 alkylthio. By introducing an O atom or an S atom through the R group, it can interact with metal elements such as Pb in the perovskite material, thereby playing a role in passivating grain boundary defects and interface defects without adding additives such as P-type dopants or interface modifiers.

[0081] In some examples, each R is independently selected from C1-C3 alkoxy or C1-C3 alkylthio. The shorter alkyl group in the R group is beneficial to the interaction between the O atom or the S atom and metal elements such as Pb in the perovskite material.

[0082] Furthermore, each R is independently selected from methoxy or methylthio. For example, the tetrathienopyrrole compound is:

[0083] 、 。

[0084] Furthermore, the present invention also provides a preparation method for the tetrathienopyrrole compound in any of the above examples.

[0085] The preparation method of the tetrathienopyrrole compound in one embodiment includes the following steps (steps S1-S6):

[0086] Step S1, subjecting compound 1 and compound 2 (tert-butylpinacol borate) to a first Suzuki coupling reaction to obtain compound 3.

[0087]

[0088] Among them, in Compound 1, X is selected from halogens, specifically such as Br.

[0089] Exemplarily, the first Suzuki coupling reaction includes the following steps:

[0090] Dissolve Compound 1 in a first solvent, add a first catalyst, react at -85°C to -75°C for 1 h to 2 h, add Compound 2, react at -85°C to -75°C for 1 h to 2 h, and then react at room temperature for 10 h to 16 h.

[0091] The first Suzuki coupling reaction is preferably carried out under a protective atmosphere.

[0092] Exemplarily, the molar ratio of Compound 1 to Compound 2 is 1∶(1.2 to 1.5), specifically such as 1∶1.2, 1∶1.3, 1∶1.4, 1∶1.5, etc.

[0093] Exemplarily, the first solvent includes, for example, but is not limited to tetrahydrofuran (THF). The method of dissolving Compound 1 in the first solvent is, for example, stirring at -78°C for 10 to 20 min.

[0094] Exemplarily, the first catalyst includes, for example, but is not limited to n-butyllithium. When adding the first catalyst, it is preferably added slowly, such as by dropwise addition.

[0095] Exemplarily, the molar ratio of Compound 1 to the first catalyst is 1∶(1.1 to 1.3), specifically such as 1∶1.1, 1∶1.15, 1∶1.2, 1∶1.25, 1∶1.3, etc.

[0096] The extraction method of Compound 3 includes, for example: extracting the reaction product with DCM, then drying the organic phase with anhydrous Mg2SO4, filtering, distilling under reduced pressure, separating and purifying the crude product with a silica gel chromatography column, and drying under vacuum.

[0097] Step S2, subject Compound 3 to a second Suzuki coupling reaction with Compound 4 to obtain Compound 5.

[0098]

[0099] In Compound 4, each X is independently selected from halogens, specifically such as Br.

[0100] Exemplarily, the second Suzuki coupling reaction includes the following steps:

[0101] Mix and dissolve Compound 3, Compound 4, a first base agent, and a second catalyst in a second solvent, and react at 80°C to 90°C for 6 h to 12 h.

[0102] The second Suzuki coupling reaction is preferably carried out under a protective atmosphere.

[0103] Exemplarily, the molar ratio of compound 3 to compound 4 is 1:(2.2 - 3), specifically, for example, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, etc.

[0104] Exemplarily, the second solvent is toluene, ethanol and water with a volume ratio of 2:1:1.

[0105] Exemplarily, the second catalyst includes, for example, but is not limited to tetrakis(triphenylphosphine)palladium.

[0106] Exemplarily, the first base agent includes, for example, but is not limited to potassium carbonate.

[0107] Exemplarily, the molar ratio of compound 3, the second catalyst and the first base agent is 1:(0.01 - 0.15):(5 - 15).

[0108] The extraction method of compound 5 includes, for example: extracting the reaction product with DCM, drying the organic phase with anhydrous Mg2SO4, filtering, distilling under reduced pressure, separating and purifying the crude product with a silica gel chromatography column, and drying in vacuum.

[0109] Step S3: React compound 5 with compound 2 in a third Suzuki coupling reaction to obtain compound 6.

[0110]

[0111] Exemplarily, the third Suzuki coupling reaction includes the following steps:

[0112] Dissolve compound 5 in a third solvent, add a third catalyst, react at -85°C to -75°C for 1 h to 2 h, add compound 2, react at -85°C to -75°C for 1 h to 2 h, and then react at room temperature for 10 h to 16 h.

[0113] The third Suzuki coupling reaction is preferably carried out under a protective atmosphere.

[0114] Exemplarily, the molar ratio of compound 5 to compound 2 is 1:(1.2 - 1.5), specifically, for example, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.

[0115] Exemplarily, the third solvent includes, for example, but is not limited to THF. The method of dissolving compound 5 in the third solvent is, for example, stirring at -78°C for 10 - 20 min.

[0116] Exemplarily, the third catalyst includes, for example, but is not limited to n-butyllithium. When adding the third catalyst, it is preferably added slowly, such as by dropwise addition.

[0117] Exemplarily, the molar ratio of compound 5 to the third catalyst is 1:(1.1 - 1.3), specifically for example 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, etc.

[0118] The extraction method of compound 6 for example includes: extracting the reaction product with DCM, then drying the organic phase with anhydrous Mg2SO4, filtering, distilling under reduced pressure, separating and purifying the crude product with a silica gel chromatography column, and drying under vacuum.

[0119] Step S4: React compound 7 with compound 8 to obtain compound 9.

[0120]

[0121] In formula (7), each X independently selects from halogens, specifically such as Br.

[0122] Exemplarily, the above substitution reaction includes the following steps:

[0123] Mix and dissolve compound 7, compound 8 and the fourth catalyst in the fourth solvent, and react at 110°C - 120°C for 12 h - 24 h.

[0124] The above substitution reaction is preferably carried out under a protective atmosphere.

[0125] Exemplarily, the molar ratio of compound 7 to compound 8 is 1:(2.2 - 2.5).

[0126] Exemplarily, the fourth solvent for example includes but is not limited to toluene.

[0127] Exemplarily, the fourth catalyst for example includes but is not limited to at least one of sodium tert - butoxide, Pd2(dba)3 and dppf. Exemplarily, the molar ratio of compound 7, sodium tert - butoxide, Pd2(dba)3 and dppf is 1:(7 - 10):(0.04 - 0.1):(0.15 - 0.3).

[0128] The extraction method of compound 9 for example includes: extracting the reaction product with DCM, then drying the organic phase with anhydrous Mg2SO4, filtering, distilling under reduced pressure, separating and purifying the crude product with a silica gel chromatography column, and drying under vacuum.

[0129] Step S5: Subject compound 9 to a halogenation reaction to obtain compound 10.

[0130]

[0131] In compound 10, each X independently selects from halogens, specifically such as Br.

[0132] Exemplarily, the halogenation reaction comprises the following steps:

[0133] Compound 9 and a halogenating agent are mixed and dissolved in a fifth solvent, and the reaction is carried out at -2°C to 0°C for 3 h to 4 h.

[0134] The above-mentioned halogenation reaction is preferably carried out under a protective atmosphere.

[0135] Exemplarily, the fifth solvent includes, but is not limited to, THF.

[0136] Exemplarily, the halogenating agent includes, but is not limited to, N-bromosuccinimide (NBS).

[0137] Exemplarily, the molar ratio of compound 9 to the halogenating agent is 1:(2 - 3), specifically, for example, 1:2, 1:2.3, 1:2.6, 1:2.8, 1:3, etc.

[0138] The extraction method of compound 10 includes, for example: extracting the reaction product with DCM, then drying the organic phase with anhydrous Mg2SO4, filtering, distilling under reduced pressure, separating and purifying the crude product with a silica gel chromatography column, and drying in vacuo.

[0139] Step S6: React compound 10 with compound 6 in a fourth Suzuki coupling reaction to obtain the tetrathienopyrrole compound.

[0140] Exemplarily, the fourth Suzuki coupling reaction comprises the following steps:

[0141] Compound 10, compound 6, a second base agent, and a sixth catalyst are mixed and dissolved in a sixth solvent, and the reaction is carried out at 80°C to 90°C for 6 h to 16 h.

[0142] The fourth Suzuki coupling reaction is preferably carried out under a protective atmosphere.

[0143] Exemplarily, the molar ratio of compound 10 to compound 6 is 1:(2.2 - 2.5), specifically, for example, 1:2.2, 1:2.3, 1:2.4, 1:2.5, etc.

[0144] Exemplarily, the sixth solvent is toluene, ethanol, and water with a volume ratio of 2:1:1.

[0145] Exemplarily, the sixth catalyst includes, but is not limited to, tetrakis(triphenylphosphine)palladium.

[0146] Exemplarily, the second base agent includes, but is not limited to, potassium carbonate.

[0147] Exemplarily, the molar ratio of compound 10, the sixth catalyst, and the second base agent is 1:(0.01 - 0.15):(5 - 15).

[0148] The extraction method of tetrathienopyrrole compounds includes, for example: extracting the reaction product with DCM, drying the organic phase with anhydrous Mg2SO4, filtering, distilling under reduced pressure, separating and purifying the crude product by silica gel chromatography column, and drying in vacuum.

[0149] Each synthesis step in the above preparation method is simple, with low cost, and suitable for industrial production.

[0150] The present invention also provides the application of the tetrathienopyrrole compounds as described above as hole transport materials. Further, the present invention also provides the application of the tetrathienopyrrole compounds as described above as materials for the hole transport layer in perovskite solar cells. Further, the present invention also provides the application of the tetrathienopyrrole compounds as described above as materials for the hole transport layer in inverted quasi-two-dimensional perovskite solar cells.

[0151] The preparation of the hole transport layer can be carried out by formulating a solution of the above-mentioned tetrathienopyrrole compounds, coating the solution on a substrate, and performing annealing treatment to form the hole transport layer. The solvents used in the solution are, for example, but not limited to dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, dichloromethane, etc. The coating methods are, for example, but not limited to spin coating method, printing method, inkjet printing method, doctor blade method, etc.

[0152] The present invention also provides a solar cell.

[0153] As Figure 1 shown, a solar cell 100 in an embodiment includes a transparent conductive substrate 110, a hole transport layer 120, a perovskite light absorption layer 130, and an electrode layer 140 stacked in sequence. Among them, the hole transport layer 120 contains the tetrathienopyrrole compounds in any of the above examples.

[0154] The perovskite light absorption layer 130 includes a perovskite precursor material (ABX3). Among them, A is a monovalent cation, including but not limited to potassium ion, methylammonium ion, formamidinium ion, methylenediamine ion, benzamidinium cation, and guanidinium cation, one or more of them. B is a divalent cation, including but not limited to lead ion, copper ion, zinc ion, gallium ion, tin ion, and calcium ion, one or more of them. X is a monovalent anion, including but not limited to fluoride ion, chloride ion, bromide ion, iodide ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, and acetate ion, one or more of them.

[0155] In some examples, the perovskite light absorption 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.

[0156] The material of the transparent conductive substrate 110 can be a conductive oxide, for example, it can be, but not limited to, one or more of oxides such as 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.

[0157] Optionally, the material of the electrode layer 140 can be, for example, but not limited to, one or more of gold, silver, copper, aluminum, and chromium.

[0158] Optionally, the solar cell 100 may further include an electron transport layer 150, and the electron transport layer 150 is disposed between the perovskite light absorption layer 130 and the electrode layer 140.

[0159] Optionally, the material of the electron transport layer 150 can be, for example, but not limited to, one or more of 1,3,5-tris(1-phenyl-1H-benzoimidazol-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).

[0160] The above solar cell 100 can be a perovskite single-layer cell or a tandem cell. Among them, the tandem cell is, for example, a perovskite / silicon tandem cell, a full perovskite tandem cell, a perovskite / organic tandem cell, a perovskite / CIGS tandem cell, a perovskite / CdTe tandem cell, a perovskite / GaAs tandem cell, etc.

[0161] The following provides specific embodiments to further illustrate the present invention. The present invention provides the following specific embodiments for better further understanding of the present invention, which are not limited to the following specific embodiments and do not constitute a limitation to the content and protection scope of the present invention.

[0162] Example 1

[0163] The molecular structure of the tetrathienopyrrole compound TP-1 provided in this embodiment is shown in the following formula.

[0164]

[0165] The preparation method of the tetrathienopyrrole compound TP-1 provided in this embodiment includes the following steps:

[0166] Step 1: Add compound 1 (4.17 g, 10 mmol) into a 500 mL three-necked flask, and then add 30 mL of dry THF. Cool to -78 °C under N2 condition and stir for 10 min. Then slowly dropwise add n-butyllithium (3.75 mL, 1.00 equiv, 1.6 M in n-hexane), and then react at -78 °C for 1 h. After that, add compound 2 (tert-butylpinacol borate, 2.75 mL, 15 mmol), continue to react at -78 °C for 1 h, and then transfer to room temperature and react for 12 h. Quench the reaction with 50 mL of deionized water, extract with saturated NaCl solution and DCM. Dry the organic phase with anhydrous Mg2SO4, filter, and finally purify by column chromatography (PE∶DCM = 15∶1) to obtain 3.6 g of white solid compound 3, with a yield of 78%. The reaction equation of the above reaction is shown as follows.

[0167]

[0168] Step 2: Weigh compound 3 (2.9 g, 6.18 mmol), compound 4 (2,3-dibromothiophene, 500 mg, 2.06 mmol), potassium carbonate (1.71 g, 12.36 mmol) and tetrakis(triphenylphosphine)palladium(0) (240 mg, 0.21 mmol), add them into a 100 ml two-necked flask. Under N2 condition, add 20 mL of toluene, 10 mL of ethanol and 10 ml of water respectively. Evacuate and replace with N2 three times, and react at 85 °C for 10 h. Cool the product to room temperature, extract with DCM, dry the organic phase with anhydrous Mg2SO4, filter, and after distillation under reduced pressure, purify by column chromatography (PE∶DCM = 10∶1) to obtain 0.94 g of compound 5, with a yield of 60%. The reaction equation of the above reaction is shown as follows.

[0169]

[0170] Step 3: Weigh compound 5 (7.55 g, 10 mmol) and add it into a 500 mL three-necked flask, and then add 30 mL of dry THF. Cool to -78 °C under N2 condition and stir for 10 min. Then slowly dropwise add n-butyllithium (3.75 mL, 1.00 equiv, 1.6 M in n-hexane), and then react at -78 °C for 1 h. After that, add compound 2 (tert-butylpinacol borate, 2.75 mL, 15 mmol), continue to react at -78 °C for 1 h, and then transfer to room temperature and react for 12 h. Quench the reaction with 50 mL of deionized water, extract with saturated NaCl solution and DCM. Dry the organic phase with anhydrous Mg2SO4, filter, and finally purify by column chromatography (PE∶DCM = 10∶1) to obtain 6.6 g of compound 6, with a yield of 75%. The reaction equation of the above reaction is shown as follows.

[0171]

[0172] Step 4: Weigh compound 7 (0.83 g, 2 mmol), compound 8 (319 mg, 2.6 mmol), sodium tert-butoxide (1.54 g, 16 mmol), Pd2(dba)3 (92 mg, 0.1 mmol) and dppf (222 mg, 0.4 mmol), and dissolve them in anhydrous toluene (30 mL). Under argon protection, react at 110 °C for 12 h. Cool the product to room temperature, extract with DCM, dry the organic phase with anhydrous Mg2SO4, filter, distill under reduced pressure, and then purify by column chromatography (PE∶DCM = 10∶1) to obtain 0.37 g of compound 9 with a yield of 47%. The reaction equation of the above reaction is shown below.

[0173]

[0174] Step 5: Weigh compound 9 (1.19 g, 3 mmol) and add it to a 500 mL three-necked flask. Then add 30 mL of dry THF. Degas the mixture and rinse it with N2 gas. Stir at 0 °C for 10 min. Then dissolve NBS (N-bromosuccinimide, 1.17 g, 6.6 mmol) in THF (20 mL) and add it dropwise to the mixture. Continue the reaction at 0 °C for 3 h. Quench the reaction with 50 mL of deionized water, extract the mixture with DCM, dry the organic phase with anhydrous Mg2SO4, filter, distill under reduced pressure, and then purify by column chromatography (PE∶DCM = 6∶1) to obtain 1.46 g of compound 10 with a yield of 88%. The reaction equation of the above reaction is shown below.

[0175]

[0176] Step 6: Weigh compound 10 (0.55 g, 1 mmol), compound 6 (2.2 g, 2.5 mmol), tetrakis(triphenylphosphine)palladium (0.01 g, 0.01 mmol) and potassium carbonate (1.4 g, 10 mmol), and add them to a 250 mL two-necked reaction flask. Under N2 conditions, add 20 mL of toluene, 10 mL of ethanol and 10 mL of water respectively, and react at 85 °C for 8 h. After the reaction is completed, cool the system to room temperature, extract the mixture with DCM, dry the organic phase with anhydrous MgSO4, filter, distill under reduced pressure, and then purify by column chromatography (PE∶DCM = 6∶1) to obtain 0.74 g of tetrathienopyrrole compound TP-1 with a yield of 39%. The reaction equation of the above reaction is shown below. The 1H NMR spectrum of tetrathienopyrrole compound TP-1 is as Figure 2 shown.

[0177] Example 2

[0178] The molecular structure of the tetrathienopyrrole compound TP-2 provided in this embodiment is shown in the following formula.

[0179]

[0180] The preparation method of the tetrathienopyrrole compound TP-2 provided in this embodiment includes the following steps:

[0181] Step 1: Add compound 1 (4.17 g, 10 mmol) into a 500 mL three-necked flask, and then add 30 mL of dry THF. Cool to -78 °C under N2 condition and stir for 10 min. Then slowly dropwise add n-butyllithium (3.75 mL, 1.00 equiv, 1.6 M in n-hexane), and then react at -78 °C for 1 h. After that, add compound 2 (tert-butanol pinacol borate, 2.75 mL, 15 mmol), continue to react at -78 °C for 1 h, and then transfer to room temperature and react for 12 h. Quench the reaction with 50 mL of deionized water, extract with saturated NaCl solution and DCM, dry the organic phase with anhydrous Mg2SO4, filter, and finally purify by column chromatography (PE∶DCM = 15∶1) to obtain 3.3 g of white solid compound 3 with a yield of 72%. The reaction formula of the above reaction is shown as follows.

[0182]

[0183] Step 2: Weigh compound 3 (2.9 g, 6.18 mmol), compound 4 (2,3-dibromothiophene, 500 mg, 2.06 mmol), potassium carbonate (1.71 g, 12.36 mmol) and tetrakis(triphenylphosphine)palladium (240 mg, 0.21 mmol), add them into a 100 ml two-necked flask, evacuate and replace with N2 three times. Add 20 mL of N,N-dimethylformamide and then 6 mL of water into the two-necked flask, stir and heat to reflux at 85 °C and react for 10 h. Cool the product to room temperature, extract with dichloromethane, and then extract with water 6 - 7 times to remove the reaction solvent. Dry the organic phase with anhydrous Mg2SO4, filter, and distill off dichloromethane under reduced pressure. Purify the crude product by silica gel column chromatography using a volume ratio of 1∶3 dichloromethane and petroleum ether as the eluent to obtain 1.10 g of compound 5 with a yield of 70%. The reaction formula of the above reaction is shown as follows.

[0184]

[0185] Step 3: Weigh compound 5 (7.55 g, 10 mmol) and add it to a 500 mL three-necked flask. Then add 30 mL of dry THF. Cool it to -78 °C under N2 and stir for 10 min. Then slowly add n-butyllithium (3.75 mL, 1.00 equiv, 1.6 M in n-hexane) dropwise. Then react at -78 °C for 1 h. After that, add compound 2 (tert-butylpinacol borate, 2.75 mL, 15 mmol) and continue to react at -78 °C for 1 h. Then transfer it to room temperature and react for 12 h. Quench the reaction with 50 mL of deionized water, extract with saturated NaCl solution and DCM. Dry the organic phase with anhydrous Mg2SO4, filter, and finally purify by column chromatography (PE∶DCM = 15∶1) to obtain 6.6 g of compound 6 with a yield of 75%. The reaction equation of the above reaction is shown as follows.

[0186]

[0187] Step 4: Weigh compound 7 (0.83 g, 2 mmol), compound 8 (361 mg, 2.6 mmol), sodium tert-butoxide (1.54 g, 16 mmol), Pd2(dba)3 (92 mg, 0.1 mmol), and dppf (222 mg, 0.4 mmol) and dissolve them in anhydrous toluene (30 mL). React at 110 °C for 12 h under argon protection. Cool the product to room temperature, extract with DCM, dry the organic phase with anhydrous Mg2SO4, filter, and after distillation under reduced pressure, purify by column chromatography (PE∶DCM = 10∶1) to obtain 0.41 g of compound 9 with a yield of 50%. The reaction equation of the above reaction is shown as follows.

[0188]

[0189] Step 5: Weigh compound 9 (1.22 g, 3 mmol) and add it to a 500 mL three-necked flask. Then add 30 mL of dry THF. After degassing the mixture, rinse it with N2 gas and stir at 0 °C for 10 min. Then dissolve NBS (N-bromosuccinimide, 1.17 g, 6.6 mmol) in THF (20 mL) and add it dropwise to the mixture. Continue to react at 0 °C for 3 h. Quench the reaction with 50 mL of deionized water, extract the mixture with DCM, dry the organic phase with anhydrous Mg2SO4, filter, and after distillation under reduced pressure, purify by column chromatography (PE∶DCM = 6∶1) to obtain 1.5 g of compound 10 with a yield of 90%. The reaction equation of the above reaction is shown as follows.

[0190]

[0191] Step 6, Weigh 1 mmol (0.57 g) of Compound 10, 2.5 mmol (2.2 g) of Compound 6, 0.01 mmol (0.01 g) of tetrakis(triphenylphosphine)palladium, and 10 mmol (1.4 g) of potassium carbonate, and add them to a 250 mL two-necked reaction flask. Under N2 atmosphere, add 20 mL of toluene, 10 mL of ethanol, and 10 mL of water respectively, and react at 85 °C for 8 h. After the reaction is completed, cool the system to room temperature. Extract the mixture with DCM, dry the organic phase with anhydrous MgSO4, filter, and purify by column chromatography (PE∶DCM = 6∶1) under reduced pressure distillation to obtain 0.80 g of tetrathienopyrrole compound TP-2 with a yield of 45%. The reaction formula of the above reaction is as follows. The 1H NMR spectrum of tetrathienopyrrole compound TP-2 is as Figure 3 shown.

[0192]

[0193] Thermogravimetric analysis was performed on TP-1 and TP-2 using a thermogravimetric analyzer. N2 was selected as the program protection gas, the purge flow rate was set to 20 cm 3 / min, the initial temperature was set to 25 °C, and the heating rate was 10 °C / min. The measured TGA curves are as Figure 4 shown. The thermal decomposition temperature T d (5% weight loss) of TP-1 is 332.5 °C, and the thermal decomposition temperature T d (5% weight loss) of TP-2 is 305.1 °C, indicating that TP-1 and TP-2 have good thermal stability and can exist stably under the annealing process.

[0194] The tetrathienopyrrole compounds TP-1 and TP-2 prepared in the above examples were used as hole transport materials in solar cells respectively, and a control experimental group using the traditional hole transport material PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]) was set up.

[0195] Specifically, the preparation process of the solar cell includes the following steps:

[0196] Step 1, Preparation of the transparent conductive substrate. Ultrasonically clean the ITO glass sheet with deionized water, acetone, and ethanol in sequence for 20 minutes, then use an N2 gas gun to blow dry the solvent residues on the surface of the ITO glass sheet, and then perform oxygen plasma treatment for 15 minutes to obtain the transparent conductive substrate, which is transferred to a nitrogen glove box.

[0197] Step 2, preparation of the hole transport layer. Weigh 5 mg of the hole transport material and dissolve it in 1 mL of chlorobenzene. Take 100 μl of the solution and uniformly coat it on the transparent conductive substrate. Spin-coat it at 5000 rpm for 25 seconds, and then anneal it at 100 °C for 10 minutes to form the hole transport layer. The hole transport materials used in different cells are tetrathienopyrrole compound TP-1, tetrathienopyrrole compound TP-2, and PTAA respectively.

[0198] Step 3, preparation of the perovskite light absorption layer. Mix 3-fluoro-benzylammonium iodide (3FBAI), ammonium chloride (MACl), and lead iodide (PbI2) in a molar ratio of 2.2∶3.5∶4 and dissolve them in a mixed solution of DMF and DMSO with a volume ratio of 4∶1 to obtain the perovskite solution. After forming the hole transport layer, the device is cooled to room temperature, preheated at 140 °C for 4 minutes, take 50 μl of the perovskite solution and coat it on the hole transport layer, spin-coat it at 4000 rpm for 25 seconds, and then anneal it at 100 °C for 10 minutes to form the perovskite light absorption layer.

[0199] Step 4, preparation of the electron transport layer. After forming the perovskite light absorption layer, the device is cooled to room temperature. Take 40 μl of a PC61BM solution with a concentration of 15 mg / mL and coat it on the perovskite light absorption layer. Spin-coat it at 1000 rpm for 40 seconds and anneal it at 80 °C for 10 minutes to form the electron transport layer.

[0200] Step 5, preparation of the electrode layer. After forming the electron transport layer, the device is transferred to a vacuum evaporation chamber, and a 6 nm Cr layer and an 80 nm Au layer are sequentially deposited on the electron transport layer to form the electrode layer, that is, the inverted quasi-two-dimensional perovskite solar cell is prepared.

[0201] The following method is used to test the performance of solar cells using different hole transport materials: Adjust the power of the solar simulator to 100 mw / cm 2 , to simulate the AM1.5G radiation standard, and read the current and voltage values of the solar cell through a computer connected to a Keithley 2450 source meter. Use a Newport standard silicon cell 91150 to calibrate the light intensity. The solar cell adopts a forward and reverse scan mode, and the scan rate is 0.05 V / s. The electrical properties obtained from the test are shown in Table 1.

[0202] Table 1 Electrical properties of solar cells using different hole transport materials

[0203]

[0204] As can be seen from the data in Table 1, the inverted solar cells using tetrathienopyrrole compounds TP-1 and TP-2 as undoped hole transport materials can obtain good open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency. Especially for the fill factor and photoelectric conversion efficiency, compared with the traditional hole transport material PTAA, the use of tetrathienopyrrole compounds TP-1 and TP-2 can achieve significant improvement.

[0205] The tetrathienopyrrole compounds of the present invention have the following advantages:

[0206] (1) The tetrathienopyrrole compounds of the present invention have good solubility in solvents such as dimethyl sulfoxide, N,N'-dimethylformamide, toluene, chlorobenzene, and dichloromethane;

[0207] (2) The raw materials for preparing the tetrathienopyrrole compounds of the present invention are low in cost, and the preparation process is simple, which is conducive to industrial production;

[0208] (3) The tetrathienopyrrole compounds of the present invention have a relatively high decomposition temperature, good thermal stability, good film-forming properties, and good wettability with the perovskite precursor solvent, which is helpful for the crystallization and film formation of perovskite;

[0209] (4) The tetrathienopyrrole compounds of the present invention have good mobility, which is beneficial to the extraction and transport of holes;

[0210] (5) The tetrathienopyrrole compounds of the present invention have a relatively deep HOMO energy level that matches the perovskite material;

[0211] (6) The tetrathienopyrrole compounds of the present invention can be used in inverted quasi-two-dimensional perovskite solar cells without adding doping agents, and have repeatability, realizing low-cost, high-performance, stable, and large-area inverted perovskite solar cells, with good application prospects.

[0212] 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-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0213] The above-described embodiments only represent several implementation manners of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the 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 invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims, and the specification can be used to explain the content of the claims.

Claims

1. A tetrathienopyrrole compound, characterized in that: It has a molecular structure shown in formula (I): ； In formula (I), each R is independently selected from H, C1~C5 alkyl, C1~C5 alkoxy or C1~C5 alkylthio.

2. The tetrathienopyrrole compound according to claim 1, characterized in that: Each R is independently selected from a C1-C3 alkoxy group or a C1-C3 alkylthio group.

3. The tetrathienopyrrole compound according to claim 2, characterized in that: Each R is independently selected from methoxy or methylthio.

4. The tetrathienopyrrole compound according to claim 3, characterized in that: The tetrathienopyrrole compound is: or .

5. A method for preparing a tetrathienopyrrole compound according to any one of claims 1 to 4, characterized in that: The following steps are involved: Compound 1 and compound 2 are subjected to a first Suzuki coupling reaction to obtain compound 3; ； ； ； In the compound 1, X is selected from halogen; The compound 3 and the compound 4 undergo a second Suzuki coupling reaction to obtain a compound 5; ； ； In the compound 4, each X is independently selected from halogen; The compound 5 and the compound 2 are subjected to a third Suzuki coupling reaction to obtain a compound 6; ； Compound 7 is subjected to substitution reaction with compound 8 to obtain compound 9; ； ； ； In formula (7), each X is independently selected from halogen; The compound 9 is subjected to a halogenation reaction to obtain a compound 10; ； In the compound 10, each X is independently selected from halogen; The compound 10 and the compound 6 are subjected to a fourth Suzuki coupling reaction to obtain the quaternary thienopyrrole compound.

6. The preparation method according to claim 5, characterized in that: The preparation method meets at least one of the following characteristics (1) to (6): (1) The first Suzuki coupling reaction comprises the following steps: Dissolve the compound 1 in a first solvent, add a first catalyst, react at -85°C to -75°C for 1h to 2h, add the compound 2, react at -85°C to -75°C for 1h to 2h, and then react at room temperature for 10h to 16h; (2) In the first Suzuki coupling reaction, the molar ratio of the compound 1 to the compound 2 is 1:(1.2-1.5); (3) The first catalyst used in the first Suzuki coupling reaction includes n-butyl lithium; (4) The second Suzuki coupling reaction comprises the following steps: The compound 3, the compound 4, the first alkali agent and the second catalyst are mixed and dissolved in a second solvent, and reacted at 80° C. to 90° C. for 6 h to 12 h; (5) In the second Suzuki coupling reaction, the molar ratio of the compound 3 to the compound 4 is 1:(2.2-3); (6) The second catalyst used in the second Suzuki coupling reaction includes tetrakis(triphenylphosphine)palladium.

7. The preparation method according to claim 5, characterized in that: The preparation method meets at least one of the following characteristics (1) to (6): (1) The third Suzuki coupling reaction comprises the following steps: Dissolve the compound 5 in a third solvent, add a third catalyst, react at -85°C to -75°C for 1h to 2h, add the compound 2, react at -85°C to -75°C for 1h to 2h, and then react at room temperature for 10h to 16h; (2) In the third Suzuki coupling reaction, the molar ratio of the compound 5 to the compound 2 is 1:(1.2-1.5); (3) The third catalyst used in the third Suzuki coupling reaction includes n-butyl lithium; (4) The substitution reaction comprises the following steps: The compound 7, the compound 8 and the fourth catalyst are mixed and dissolved in a fourth solvent, and reacted at 110° C. to 120° C. for 12 h to 24 h; (5) In the substitution reaction, the molar ratio of the compound 7 to the compound 8 is 1:(2.2-2.5); (6) The fourth catalyst used in the substitution reaction includes at least one of sodium tert-butoxide, Pd2(dba)3 and dppf.

8. The preparation method according to any one of claims 5 to 7, characterized in that The preparation method meets at least one of the following characteristics (1) to (6): (1) The halogenation reaction comprises the following steps: The compound 9 and the halogenating agent are mixed and dissolved in a fifth solvent, and reacted at -2°C to 0°C for 3h to 4h; (2) The halogenating agent used in the halogenation reaction includes N-bromosuccinimide; (3) In the halogenation reaction, the molar ratio of the compound 9 to the halogenating agent is 1:(2-3); (4) The fourth Suzuki coupling reaction comprises the following steps: The compound 10, the compound 6, the second alkali agent and the sixth catalyst are mixed and dissolved in a sixth solvent, and reacted at 80° C. to 90° C. for 6 h to 16 h; (5) In the fourth Suzuki coupling reaction, the molar ratio of the compound 10 to the compound 6 is 1:(2.2-2.5); (6) The sixth catalyst used in the fourth Suzuki coupling reaction includes tetrakis(triphenylphosphine)palladium.

9. Use of the tetrathienopyrrole compound according to any one of claims 1 to 4 as a hole transport material.

10. A solar cell, characterized in that: The invention comprises a transparent conductive substrate, a hole transport layer, a perovskite light absorption layer and an electrode layer which are stacked in sequence, wherein the hole transport layer comprises the tetrathienopyrrole compound according to any one of claims 1 to 4.

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