Preparation method and application of self-assembled hole transport material

Abstract

The invention belongs to the field of photovoltaic materials, and provides a preparation method and application of a self-assembly hole transport material.The preparation method synthesizes a class of new carbazole derivatives through a new process synthesis route, five classes of self-assembly hole transport materials can be synthesized and prepared through four steps, the legal method is simple, the cost is low, and the method is suitable for large-scale production. And expensive raw materials can be avoided, the yield is high, and the method is suitable for large-scale preparation. In the third step of the preparation method, a bromocarbazole substituent coupling substitution reaction is taken as a purpose, so that the process of connecting the hydrophilic group containing the aromatic ring is realized, and equivalently, a method for introducing the hydrophilic functional group containing the aromatic ring to the upper end of carbazole is included and provided. The self-assembled hole transport material obtained by the preparation method can achieve the effects of improving hydrophilicity and optimizing a passivated perovskite lower interface, so that the conversion efficiency and the stability of a perovskite battery can be further improved.

Description

Technical Field

[0001] The invention belongs to the field of photovoltaic materials and relates to a preparation method and application of a self-assembled hole transport material. Background Art

[0002] Perovskite solar cells have attracted much attention due to their high efficiency, low cost and easy preparation. The hole transport layer (hole transport material) is a key component in perovskite solar cells. Its main function is to transfer the generated holes from the perovskite layer to the electrode layer after the perovskite absorbs photons, thereby improving the photoelectric conversion efficiency of the cell.

[0003] At present, researchers have developed a variety of hole transport materials with excellent performance. These materials can be divided into multiple categories according to different classification standards: for example, based on chemical properties, existing hole transport materials include inorganic materials and organic materials; for example, based on the structural characteristics of perovskites, they can be divided into normal structure (nip) hole transport materials and inverted structure (pin) hole transport materials; specifically, in current perovskite devices, commonly used hole transport materials include NiO x , CuI, spiro-OMeTAD, PTAA and self-assembled small molecule (SAM) materials, etc.

[0004] Compared with other hole transport materials, self-assembled small molecule (SAM) materials have been rapidly developed because they can be used in inverted structure batteries. Among them, carbazole self-assembled small molecule hole transport materials with phosphoric acid as anchor group have increased the efficiency of pin structure batteries to more than 26%, and have very good application prospects. However, the surface of existing SAM materials (such as carbazole butylphosphonic acid, 3,6-diphenylcarbazole butylphosphonic acid, etc.) is a non-hydrophilic group, which leads to very poor wettability of perovskite precursor solution on the surface of small molecule layer. When preparing large-area perovskite film, there will be solution polycondensation, and the precursor solution is difficult to spread well on the surface of small molecules, which will cause holes in the perovskite film, which has a negative impact on the preparation of large-area perovskite film and components, and also cannot play the effect of passivating the lower interface of perovskite. All of the above lead to the problem of poor quality and stability of large-area perovskite film formation, which limits the further application of such materials and the further development of perovskite devices. Summary of the invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide a preparation method and application of a self-assembled hole transport material, synthesize a new type of carbazole derivatives through a new process synthesis route, and synthesize five types of self-assembled hole transport materials in four steps. The legal method is simple, can avoid the use of expensive raw materials, and has a high yield, which is suitable for mass production. The obtained self-assembled hole transport material can achieve the effect of improving hydrophilicity and optimizing the passivation of the lower interface of perovskite, thereby helping to further improve the conversion efficiency and stability of perovskite cells.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a second aspect, the present invention provides a method for preparing the self-assembled hole transport material according to the first aspect, the preparation method comprising:

[0008] (1) mixing the raw material compound VIII with the raw material compound VII, and carrying out an alkylation reaction under the action of a strong base and a phase transfer catalyst to produce an intermediate compound VI;

[0009]

[0010] Wherein, n is an integer between 2 and 6, such as 2, 3, 4, 5 or 6; X 11 , X 12 and X2 are each independently selected from any one of halogen;

[0011] (2) mixing the intermediate compound VI with the raw material compound V or the raw material compound V' to carry out a substitution reaction to generate the intermediate compound IV;

[0012]

[0013] Wherein, L is selected from any one of C2 to C4 straight chain alkyl groups;

[0014] (3) mixing the intermediate compound IV with the raw material compound IIIa and the raw material compound IIIb in a solvent, and performing a coupling reaction under the action of an alkaline substance and a coupling catalyst to produce the intermediate compound II;

[0015]

[0016] Among them, R 11 and R 12 The same or different, each independently selected from any one of the following groups:

[0017]

[0018] m1, m2, m3, m4 and m5 represent the number of corresponding groups, and m1, m2, m3, m4 and m5 are each independently selected from integers between 1 and 5, such as 1, 2, 3, 4 or 5; the dotted line represents the attachment site of the group;

[0019] (4) subjecting the intermediate compound II to a hydrolysis reaction to generate a self-assembled hole transport material having a structure as shown in Formula I;

[0020]

[0021] The method of the present invention adopts four steps to synthesize and prepare five types of self-assembled hole transport materials, and the legal method is simple, the yield is high, and it is suitable for mass production. Specifically, the preparation method of the present invention can avoid the use of expensive raw materials, and the third step is to use the bromine carbazole substituent coupling substitution reaction as the purpose, and then connect the hydrophilic group containing aromatic rings, considering that the carbazole containing methoxyphenyl, methylthiophenyl and other hydrophilic group substituents containing aromatic rings cannot be directly bought at a lower price on the market, so the present invention is also equivalent to providing a method for introducing a hydrophilic functional group containing aromatic rings at the upper end of carbazole. If the first step in the present invention uses carbazole containing methoxyphenyl, methylthiophenyl and other hydrophilic substituents containing aromatic rings or dibromocarbazole in the first step first undergoes coupling substitution reaction, then the synthetic route of each final product requires at least three or four completely different reaction nodes, thereby causing cost increase, and causing yield and production schedule to be affected.

[0022] As a preferred technical solution of the present invention, in step (1), the raw material compound VIII includes a compound having the following structure:

[0023]

[0024] Preferably, it is at least one of 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane and 1,6-dibromohexane, which is any of dibromoalkanes having bromine groups at both ends.

[0025] Preferably, the raw material compound VII is 3,6-dibromocarbazole (denoted as VIIa) or 3,6-dichlorocarbazole (denoted as VIIb);

[0026]

[0027] Preferably, the strong base comprises potassium hydroxide and / or sodium hydroxide.

[0028] Preferably, the strong base is an aqueous solution with a concentration of 20% to 60%, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% or 60%.

[0029] Preferably, the phase transfer catalyst comprises tetrabutylammonium bromide and / or tetrabutylammonium iodide.

[0030] Preferably, the alkylation reaction is carried out under reflux and stirring under a protective atmosphere.

[0031] Preferably, the temperature of the alkylation reaction is 20-70°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C or 70°C.

[0032] Preferably, the alkylation reaction time is 8 to 16 h, such as 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h or 16 h, etc., so that the yield of the intermediate compound VI is ≥90%, such as 90%, 91%, 92%, 93%, 94% or 95%, etc.

[0033] Preferably, the intermediate compound VI is any one of 3,6-dibromocarbazole ethyl bromide, 3,6-dibromocarbazole propyl bromide, 3,6-dibromocarbazole butyl bromide, 3,6-dibromocarbazole pentyl bromide or 3,6-dibromocarbazole hexyl bromide.

[0034] As a preferred technical solution of the present invention, in step (2), the raw material compound V is triethyl phosphite (denoted as Va), and the raw material compound V' is diethyl phosphite (denoted as V'a);

[0035]

[0036] Preferably, the substitution reaction is carried out under reflux and stirring under a protective atmosphere.

[0037] Preferably, the substitution reaction time is 12 to 36 h, for example, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h or 36 h, so that the yield of the intermediate compound IV is ≥95%, for example, 95%, 96%, 97%, 98% or 99%, etc.

[0038] Preferably, the intermediate compound IV is any one of 3,6-dibromocarbazole ethylphosphonic acid diethyl ester, 3,6-dibromocarbazole propylphosphonic acid diethyl ester, 3,6-dibromocarbazole butylphosphonic acid diethyl ester, 3,6-dibromocarbazole pentylphosphonic acid diethyl ester or 3,6-dibromocarbazole hexylphosphonic acid diethyl ester.

[0039] As a preferred technical solution of the present invention, in step (3) of the present invention, R 11 and R 12 Preferably, it is any one of the following groups:

[0040]

[0041] That is, in step (3), the chemical formulas of the raw material compound IIIa and the raw material compound IIIb are R1B(OH)2 and R2B(OH)2, respectively, and are preferably independently selected from any one of 4-methoxyphenylboronic acid, 4-methylthiophenylboronic acid, 4-cyanophenylboronic acid, 4-formylaminophenylboronic acid or 4-carboxyphenylboronic acid.

[0042] Preferably, R 11 and R 12 are the same group, that is, the raw material compound IIIa is the same as the raw material compound IIIb.

[0043] In the present invention, considering the difficulty, synthesis yield and cost of the synthesis, R 11 and R 12 For the same group, the types of raw materials used can be reduced.

[0044] In the present invention, when the raw material compound IIIa is the same as the raw material compound IIIb, the raw material compound IIIa and the raw material compound IIIb are uniformly recorded as raw material compound III', the chemical formula is RB(OH)2, and the structural formula is:

[0045]

[0046] R is selected from any one of the following groups:

[0047]

[0048] m1, m2, m3, m4 and m5 represent the number of corresponding groups, and m1, m2, m3, m4 and m5 are each independently selected from integers between 1 and 5, such as 1, 2, 3, 4 or 5; the dotted line represents the connection site of the group.

[0049] Preferably, R is any one of p-methoxyphenyl, p-methylthiophenyl, p-cyanophenyl, p-formylaminophenyl or p-carboxyphenyl, that is, the raw material compound III' is any one of 4-methoxyphenylboronic acid, 4-methylthiophenylboronic acid, 4-cyanophenylboronic acid, 4-formylaminophenylboronic acid or 4-carboxyphenylboronic acid.

[0050] As a preferred technical solution of the present invention, the method for preparing the self-assembled hole transport material comprises:

[0051] (1) mixing the raw material compound VIIIa with the raw material compound VIIa, and subjecting the mixture to an alkylation reaction under the action of a strong base and a phase transfer catalyst to generate an intermediate compound VIa;

[0052]

[0053] Wherein, n is an integer between 2 and 6, such as 2, 3, 4, 5 or 6;

[0054] (2) mixing the intermediate compound VIa with the raw material compound Va or the raw material compound V'a to carry out a substitution reaction to generate the intermediate compound IVa;

[0055]

[0056] (3) mixing the intermediate compound IVa and the raw material compound III' in a solvent, and performing a coupling reaction under the action of an alkaline substance and a coupling catalyst to produce an intermediate compound II';

[0057]

[0058] Wherein, R is any one of p-methoxyphenyl, p-methylthiophenyl, p-cyanophenyl, p-formylaminophenyl or p-carboxyphenyl;

[0059] (4) subjecting the intermediate compound II' to a hydrolysis reaction to generate a self-assembled hole transport material having a structure represented by formula I';

[0060]

[0061] As a preferred technical solution of the present invention, in step (3), the solvent includes N,N-dimethylacetamide and / or tetrahydrofuran.

[0062] Preferably, the alkaline substance comprises potassium carbonate and / or sodium carbonate.

[0063] Preferably, the coupling catalyst comprises tetrakis(triphenylphosphine)palladium and / or palladium acetate.

[0064] Preferably, the coupling reaction is carried out under reflux and stirring under a protective atmosphere.

[0065] Preferably, the coupling reaction temperature is 70-180°C, for example, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C or 180°C, etc., preferably 160-180°C.

[0066] Preferably, the coupling reaction time is 18 to 30 h, for example, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h or 30 h, and the yield of the intermediate compound II (or intermediate compound II') is ≥80%, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89% or 90%, etc.

[0067] Preferably, the intermediate compound II (or intermediate compound II') is bis(4-methoxy)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-methylthio)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-cyano)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-carboxyl)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-formylamino)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-methoxy)-3,6-diphenylcarbazoleethyl diethyl phosphate, Phenylcarbazole propyl diethyl phosphate, bis(4-methylthio)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-cyano)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-carboxyl)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-formylamino)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-methoxy)-3,6-diphenylcarbazole butyl diethyl phosphate, bis(4-methylthio)-3,6-diphenylcarbazole butyl diethyl phosphate, bis( 4-cyano)-3,6-diphenylcarbazole butyl phosphate diethyl ester, bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate diethyl ester, bis(4-formylamino)-3,6-diphenylcarbazole butyl phosphate diethyl ester, bis(4-methoxy)-3,6-diphenylcarbazole pentyl phosphate diethyl ester, bis(4-methylthio)-3,6-diphenylcarbazole pentyl phosphate diethyl ester, bis(4-cyano)-3,6-diphenylcarbazole pentyl phosphate diethyl ester, bis(4-carboxyl)-3,6-diphenylcarbazole Any one of pentyl phosphate diethyl ester, bis(4-formylamino)-3,6-diphenylcarbazole pentyl phosphate diethyl ester, bis(4-methoxy)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-methylthio)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-cyano)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-carboxy)-3,6-diphenylcarbazole hexyl phosphate diethyl ester or bis(4-formylamino)-3,6-diphenylcarbazole hexyl phosphate diethyl ester.

[0068] As a preferred technical solution of the present invention, in step (4), the hydrolysis reaction is carried out under a protective atmosphere with stirring at room temperature.

[0069] Preferably, the hydrolysis reaction comprises a hydrolysis aid, and the hydrolysis aid comprises trimethylsilyl bromide.

[0070] Preferably, the hydrolysis reaction comprises an auxiliary solvent, and the auxiliary solvent comprises 1,4-dioxane and / or dichloromethane.

[0071] Preferably, the self-assembled hole transport material having the structure shown in Formula I (or Formula I') includes a compound having the following specific structure:

[0072]

[0073]

[0074]

[0075] That is, when n=2, the obtained self-assembled hole transport material is a 2PACz-type material, preferably any one of bis(4-methoxy)-3,6-diphenylcarbazoleethyl phosphate (denoted as 2P-1), bis(4-methylthio)-3,6-diphenylcarbazoleethyl phosphate (denoted as 2P-2), bis(4-cyano)-3,6-diphenylcarbazoleethyl phosphate (denoted as 2P-3), bis(4-formylamino)-3,6-diphenylcarbazoleethyl phosphate (denoted as 2P-4) and bis(4-carboxyl)-3,6-diphenylcarbazoleethyl phosphate (denoted as 2P-5);

[0076] That is, when n=3, the obtained self-assembled hole transport material is a 3PACz-type material, preferably any one of bis(4-methoxy)-3,6-diphenylcarbazole propyl phosphate (denoted as 3P-1), bis(4-methylthio)-3,6-diphenylcarbazole propyl phosphate (denoted as 3P-2), bis(4-cyano)-3,6-diphenylcarbazole propyl phosphate (denoted as 3P-3), bis(4-formylamino)-3,6-diphenylcarbazole propyl phosphate (denoted as 3P-4) and bis(4-carboxyl)-3,6-diphenylcarbazole propyl phosphate (denoted as 3P-5);

[0077] That is, when n=4, the obtained self-assembled hole transport material is a 4PACz-based material, preferably any one of bis(4-methoxy)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-1), bis(4-methylthio)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-2), bis(4-cyano)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-3), bis(4-formylamino)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-4) and bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-5);

[0078] That is, when n=5, the obtained self-assembled hole transport material is a 5PACz-type material, preferably any one of bis(4-methoxy)-3,6-diphenylcarbazole pentyl phosphate (denoted as 5P-1), bis(4-methylthio)-3,6-diphenylcarbazole pentyl phosphate (denoted as 5P-2), bis(4-cyano)-3,6-diphenylcarbazole pentyl phosphate (denoted as 5P-3), bis(4-formylamino)-3,6-diphenylcarbazole pentyl phosphate (denoted as 5P-4) and bis(4-carboxyl)-3,6-diphenylcarbazole pentyl phosphate (denoted as 5P-5);

[0079] That is, when n=6, the obtained self-assembled hole transport material is a 6PACz-type material, preferably any one of bis(4-methoxy)-3,6-diphenylcarbazole hexyl phosphate (denoted as 6P-1), bis(4-methylthio)-3,6-diphenylcarbazole hexyl phosphate (denoted as 6P-2), bis(4-cyano)-3,6-diphenylcarbazole hexyl phosphate (denoted as 6P-3), bis(4-formylamino)-3,6-diphenylcarbazole hexyl phosphate (denoted as 6P-4) and bis(4-carboxyl)-3,6-diphenylcarbazole hexyl phosphate (denoted as 6P-5).

[0080] Since the lower end of the self-assembled hole transport material needs to be anchored with ITO, FTO or other metal oxides, the upper end of the self-assembled material needs to contact the perovskite to form a hole transport layer film. However, the existing carbazole has insufficient wettability for the perovskite precursor solution, resulting in the perovskite precursor solution not being able to spread well. To this end, a class of carbazole derivatives obtained by the preparation method of the present invention is used as a self-assembled monolayer hole transport material, so that it has a phosphonic acid anchoring group to achieve monolayer self-assembly, and at the same time, hydrophilic groups containing aromatic rings are introduced on one side of the two benzene rings in the carbazole, and the hydrophilic groups containing aromatic rings include any one of methoxyphenyl, methylthiophenyl, cyanophenyl, formylaminophenyl or carboxylphenyl. The hydrophilic groups containing aromatic rings can effectively improve the good wettability of the perovskite precursor solution on the self-assembled monolayer, and at the same time, the hydrophilic groups containing aromatic rings can form a good complexation with the perovskite component, such as lead, so as to achieve the purpose of passivating the lower interface of the perovskite; at the same time, the increased aromatic rings in the increased carbazole can adjust the energy levels of the self-assembled small molecules and the perovskite layer, better match the perovskite, optimize the charge transfer efficiency of the battery, and finally achieve the effect of improving the conversion efficiency and stability of the perovskite battery.

[0081] In a second aspect, the present invention provides a hole transport layer comprising a self-assembled hole transport material obtained by the preparation method described in the first aspect.

[0082] In a third aspect, the present invention provides a method for preparing the hole transport layer described in the second aspect, wherein the self-assembled hole transport material is formulated into a precursor solution, the precursor solution is used for film formation, and then the hole transport layer is obtained after annealing.

[0083] As a preferred technical solution of the present invention, the solvent in the precursor solution includes at least one of methanol, ethanol, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide or N-methylpyrrolidone.

[0084] Preferably, the concentration of the self-assembled hole transport material in the precursor solution is 0.1 to 5 mg / mL, for example, 0.1 mg / mL, 0.5 mg / mL, 0.8 mg / mL, 1 mg / mL, 1.5 mg / mL, 2 mg / mL, 2.5 mg / mL, 3 mg / mL, 3.5 mg / mL, 4 mg / mL, 4.5 mg / mL or 5 mg / mL, etc.

[0085] Preferably, the film forming method comprises coating, and the coating comprises at least one of spin coating, spray coating, blade coating or dip coating (dip coating).

[0086] Preferably, the annealing temperature is 100-120°C, for example, 100°C, 105°C, 110°C, 115°C or 120°C.

[0087] Preferably, the thickness of the hole transport layer is 10 to 200 nm, for example, 10 min, 30 min, 50 min, 80 min, 100 min, 120 min, 140 min, 160 min, 180 min or 200 min.

[0088] In a fourth aspect, the present invention provides a battery assembly comprising the hole transport layer described in the second aspect, or the hole transport layer obtained by the preparation method described in the third aspect.

[0089] The self-assembled hole transport material of the present invention has the function of passivating the interface under the perovskite layer and improving the hydrophilicity, and can be used for but not limited to perovskite solar cells, and can also be used for the preparation of components such as perovskite LEDs or perovskite sensors.

[0090] As a preferred technical solution of the present invention, the battery assembly includes a conductive substrate, the hole transport layer, the perovskite layer, the electron transport layer and an electrode.

[0091] Preferably, the battery assembly further comprises a passivation layer.

[0092] Preferably, the conductive substrate comprises any one of FTO conductive glass, ITO conductive glass, FTO conductive plastic or ITO conductive plastic; wherein the FTO film layer has a thickness of 500 to 600 nm, such as 500 nm, 510 nm, 520 nm, 530 nm, 540 nm, 550 nm, 560 nm, 570 nm, 580 nm, 590 nm or 600 nm, and the ITO film layer has a thickness of 300 to 400 nm, such as 300 nm, 310 nm, 320 nm, 330 nm, 340 nm, 350 nm, 360 nm, 370 nm, 380 nm, 390 nm or 400 nm, etc.

[0093] Preferably, the hole transport layer has a thickness of 10 to 200 nm, for example, 10 nm, 30 nm, 50 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm or 200 nm.

[0094] Preferably, the perovskite material of the perovskite layer comprises MA x FA 1-x CxP 3-a Br a 、MA y FA 1-y CxP 3- b Cl b 、MA z FA 1-z Cb 3-c Cl c , wherein x, y and z are each independently selected from 0 to 1, such as 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 1, a, b and c are each independently selected from 0 to 3, such as 0, 0.3, 0.5, 0.8, 1, 1.3, 1.5, 1.8, 2, 2.2, 2.5, 2.8 or 3, and the structural formula of MA is CH3NH3 + , the structural formula of FA is CH(NH2)2 + .

[0095] Preferably, the thickness of the perovskite layer is 300 to 1000 nm, for example, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm, 700 nm, 750 nm, 800 nm, 850 nm, 900 nm, 950 nm or 1000 nm.

[0096] Preferably, the electron transport layer comprises any one of SnO2, TiO2, ZnO, Al2O3, fullerene and derivatives thereof.

[0097] Preferably, the thickness of the electron transport layer is 10 to 50 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm or 50 nm.

[0098] Preferably, the electrode comprises any one of Ag, Al, Au, IWO or ITO.

[0099] Preferably, the thickness of the electrode is 100-200 nm, for example, 100 nm, 110 nm, 120 nm, 130 nm, 140 nm, 150 nm, 160 nm, 170 nm, 180 nm, 190 nm or 200 nm.

[0100] It should be noted that the present invention does not specifically limit the specific preparation methods and processes of other layer structures in the battery assembly except the hole transport layer formed by the self-assembled hole transport material, and should be reasonably adjusted and selected according to needs. For example, the TCO film layer on the conductive substrate can be prepared by physical vapor deposition, evaporation or sputtering; the perovskite layer, electron transport layer or passivation layer can be prepared by any of the methods such as spin coating, spray coating or scraping; the electrode can be prepared by vacuum evaporation or vacuum sputtering.

[0101] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0102] The method of the present invention adopts four steps to synthesize and prepare five types of self-assembled hole transport materials, and the legal method is simple, the yield is high, and it is suitable for mass production. Specifically, the preparation method of the present invention can avoid the use of expensive raw materials, and the third step is to use the bromine carbazole substituent coupling substitution reaction as the purpose, and then connect the hydrophilic group containing aromatic rings, considering that the carbazole containing methoxyphenyl, methylthiophenyl and other hydrophilic group substituents containing aromatic rings cannot be directly bought at a lower price on the market, so the present invention is also equivalent to providing a method for introducing a hydrophilic functional group containing aromatic rings at the upper end of carbazole. If the first step in the present invention uses carbazole containing methoxyphenyl, methylthiophenyl and other hydrophilic substituents containing aromatic rings or dibromocarbazole in the first step first undergoes coupling substitution reaction, then the synthetic route of each final product requires at least three or four completely different reaction nodes, thereby causing cost increase, and causing yield and production schedule to be affected.

[0103] A type of carbazole derivative obtained by the preparation method of the present invention is used as a self-assembled monolayer hole transport material, which has a phosphonic acid anchoring group to achieve monolayer self-assembly; at the same time, a hydrophilic group containing an aromatic ring is introduced into one side of the two benzene rings in the carbazole, and the hydrophilic group containing an aromatic ring includes any one of a methoxyphenyl group, a methylthiophenyl group, a cyanophenyl group, a formylaminophenyl group or a p-carboxyphenyl group. The hydrophilic group containing an aromatic ring can effectively improve the good wettability of a perovskite precursor solution on the self-assembled monolayer, and at the same time, the hydrophilic group containing an aromatic ring can form a good complexation with the perovskite component, thereby achieving the purpose of passivating the lower interface of the perovskite; at the same time, the increased aromatic ring in the increased carbazole can adjust the energy level of the self-assembled small molecule and the perovskite layer, better match the perovskite, optimize the charge transmission efficiency of the battery, and finally achieve the effect of improving the conversion efficiency and stability of the perovskite battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] Figure 1-Figure 7 They are respectively the test results of the proton nuclear magnetic resonance spectrometer of the self-assembled hole transport materials obtained in Examples 1-7;

[0105] Figure 8-Figure 16 The contact angle test results of the hole transport layer made of the hole transport material obtained in Examples 1-7 and Control Group 1-2 on the perovskite solution are shown respectively. DETAILED DESCRIPTION

[0106] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0107] Example 1

[0108] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0109] (1) mixing the raw material compounds 1,4-dibromobutane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 35° C. to carry out an alkylation reaction for 12 hours under the action of a strong base aqueous solution of potassium hydroxide with a concentration of 50% and a phase transfer catalyst of tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole butyl bromide with a yield of ≥90%;

[0110] (2) mixing the intermediate compound 3,6-dibromocarbazole butyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester, with a yield of ≥95%;

[0111] (3) mixing the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester and the raw material compound 4-methoxyphenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction in a nitrogen atmosphere at 170° C. for 24 hours under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(4-methoxy)-3,6-diphenylcarbazole butylphosphonic acid diethyl ester, with a yield of ≥80%;

[0112] (4) The intermediate compound bis(4-methoxy)-3,6-diphenylcarbazole butyl phosphate diethyl ester is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate the product, thereby completing the hydrolysis reaction and generating the bis(4-methoxy)-3,6-diphenylcarbazole butyl phosphate.

[0113] The self-assembled hole transport material obtained in Example 1 is bis(4-methoxy)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-1), and the structure of the compound is:

[0114]

[0115] Figure 1 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of the bis(4-methoxy)-3,6-diphenylcarbazole butyl phosphate obtained in Example 1. It can be seen from the graph that the structure of the obtained compound is correct.

[0116] Example 2

[0117] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0118] (1) Mixing the raw material compounds 1,4-dibromobutane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 35° C. to carry out an alkylation reaction for 12 hours under the action of a strong base of 50% potassium hydroxide and a phase transfer catalyst tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole butyl bromide with a yield of ≥90%;

[0119] (2) mixing the intermediate compound 3,6-dibromocarbazole butyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester, with a yield of ≥95%;

[0120] (3) mixing the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester and the raw material compound 4-methylthiophenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction in a nitrogen atmosphere at 170° C. for 24 hours under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(4-methylthio)-3,6-diphenylcarbazole butylphosphonic acid diethyl ester, with a yield of ≥80%;

[0121] (4) The intermediate compound bis(4-methylthio)-3,6-diphenylcarbazole butyl phosphate diethyl ester is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate the product, thereby completing the hydrolysis reaction to generate the bis(4-methylthio)-3,6-diphenylcarbazole butyl phosphate.

[0122] The self-assembled hole transport material obtained in Example 2 is bis(4-methylthio)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-2), and the structure of the compound is:

[0123]

[0124] Figure 2 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of bis(4-methylthio)-3,6-diphenylcarbazole butyl phosphate obtained in Example 2. It can be seen from the graph that the structure of the obtained compound is correct.

[0125] Example 3

[0126] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0127] (1) Mixing the raw material compounds 1,4-dibromobutane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 35° C. to carry out an alkylation reaction for 12 hours under the action of a strong base of 50% potassium hydroxide and a phase transfer catalyst tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole butyl bromide with a yield of ≥90%;

[0128] (2) mixing the intermediate compound 3,6-dibromocarbazole butyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester, with a yield of ≥95%;

[0129] (3) mixing the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester and the raw material compound 4-cyanophenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction in a nitrogen atmosphere at 170° C. for 24 hours under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(4-cyano)-3,6-diphenylcarbazole butylphosphonic acid diethyl ester with a yield of ≥80%;

[0130] (4) The intermediate compound bis(4-cyano)-3,6-diphenylcarbazole butyl phosphate diethyl ester is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate the product, thereby completing the hydrolysis reaction and generating the bis(4-cyano)-3,6-diphenylcarbazole butyl phosphate.

[0131] The self-assembled hole transport material obtained in Example 3 is bis(4-cyano)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-3), and the structure of the compound is:

[0132]

[0133] Figure 3 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of the bis(4-cyano)-3,6-diphenylcarbazole butyl phosphate obtained in Example 3. It can be seen from the graph that the structure of the obtained compound is correct.

[0134] Example 4

[0135] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0136] (1) Mixing the raw material compounds 1,4-dibromobutane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 35° C. to carry out an alkylation reaction for 12 hours under the action of a strong base of 50% potassium hydroxide and a phase transfer catalyst tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole butyl bromide with a yield of ≥90%;

[0137] (2) mixing the intermediate compound 3,6-dibromocarbazole butyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester, with a yield of ≥95%;

[0138] (3) mixing the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester and the raw material compound 4-formylaminophenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction in a nitrogen atmosphere at 170° C. for 24 hours under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(4-formylamino)-3,6-diphenylcarbazole butylphosphonic acid diethyl ester with a yield of ≥80%;

[0139] (4) The intermediate compound bis(4-formylamino)-3,6-diphenylcarbazole butyl phosphate diethyl ester is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate, and the product completes a hydrolysis reaction to generate the bis(4-formylamino)-3,6-diphenylcarbazole butyl phosphate.

[0140] The self-assembled hole transport material obtained in Example 4 is bis(4-formylamino)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-4), and the structure of the compound is:

[0141]

[0142] Figure 4 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of the bis(4-formamido)-3,6-diphenylcarbazole butyl phosphate obtained in Example 4. It can be seen from the graph that the structure of the obtained compound is correct.

[0143] Example 5

[0144] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0145] (1) Mixing the raw material compounds 1,4-dibromobutane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 35° C. to carry out an alkylation reaction for 12 hours under the action of a strong base of 50% potassium hydroxide and a phase transfer catalyst tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole butyl bromide with a yield of ≥90%;

[0146] (2) mixing the intermediate compound 3,6-dibromocarbazole butyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester, with a yield of ≥95%;

[0147] (3) mixing the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester and the raw material compound 4-carboxyphenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction at 170° C. for 24 hours under a nitrogen atmosphere under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(4-carboxyl)-3,6-diphenylcarbazole butylphosphonic acid diethyl ester, with a yield of ≥80%;

[0148] (4) The intermediate compound bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate diethyl ester is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate the product, thereby completing the hydrolysis reaction and generating the bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate.

[0149] The self-assembled hole transport material obtained in Example 5 is bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-4), and the structure of the compound is:

[0150]

[0151] Figure 5 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of the bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate obtained in Example 5. It can be seen from the graph that the structure of the obtained compound is correct.

[0152] Example 6

[0153] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0154] (1) mixing the raw material compound 1,2-dibromoethane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 25° C. to carry out an alkylation reaction for 12 hours under the action of a strong base of 50% potassium hydroxide and a phase transfer catalyst tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole ethyl bromide with a yield of ≥90%;

[0155] (2) mixing the intermediate compound 3,6-dibromocarbazoleethyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazoleethylphosphonic acid diethyl ester, with a yield of ≥95%;

[0156] (3) mixing the intermediate compound 3,6-dibromocarbazoleethylphosphonic acid diethyl ester and the raw material compound 4-methylthiophenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction at 170° C. for 24 hours under a nitrogen atmosphere under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(4-methylthio)-3,6-diphenylcarbazoleethylphosphonic acid diethyl ester, with a yield of ≥80%;

[0157] (4) The intermediate compound bis(4-methylthio)-3,6-diphenylcarbazoleethyl diethyl phosphate is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate the product, thereby completing the hydrolysis reaction to generate the bis(4-methylthio)-3,6-diphenylcarbazoleethyl phosphate.

[0158] The self-assembled hole transport material obtained in Example 6 is bis(4-methylthio)-3,6-diphenylcarbazoleethyl phosphate (denoted as 2P-2), and the structure of the compound is:

[0159]

[0160] Figure 6 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of bis(4-methylthio)-3,6-diphenylcarbazoleethyl phosphate obtained in Example 6. It can be seen from the graph that the structure of the obtained compound is correct.

[0161] Example 7

[0162] This embodiment provides a method for preparing a self-assembled hole transport material, comprising:

[0163] (1) Mixing the raw material compounds 1,4-dibromobutane and 3,6-dibromocarbazole, and refluxing and stirring in a nitrogen atmosphere at 25° C. to carry out an alkylation reaction for 12 hours under the action of a strong base of 50% potassium hydroxide and a phase transfer catalyst tetrabutylammonium bromide to generate an intermediate compound 3,6-dibromocarbazole butyl bromide with a yield of ≥90%;

[0164] (2) mixing the intermediate compound 3,6-dibromocarbazole butyl bromide with triethyl phosphite, and refluxing and stirring under a nitrogen atmosphere to carry out a substitution reaction for 24 hours to generate the intermediate compound 3,6-dibromocarbazole ethylphosphonic acid dibutyl ester, with a yield of ≥95%;

[0165] (3) mixing the intermediate compound 3,6-dibromocarbazole butylphosphonic acid diethyl ester and the raw material compound 3-methylthiophenylboronic acid in a solvent N,N-dimethylacetamide, and performing a coupling reaction at 170° C. for 24 hours under a nitrogen atmosphere under the action of an alkaline substance potassium carbonate and a coupling catalyst tetrakis(triphenylphosphine)palladium to generate an intermediate compound bis(3-methylthio)-3,6-diphenylcarbazole butylphosphonic acid diethyl ester, with a yield of ≥80%;

[0166] (4) The intermediate compound bis(3-methylthio)-3,6-diphenylcarbazole butyl phosphate diethyl ester is mixed with 1,4-dioxane, and under the action of trimethylsilyl bromide, the mixture is stirred at room temperature for 12 hours under a nitrogen atmosphere, and the 1,4-dioxane is removed by rotary evaporation under reduced pressure; methanol is then added and stirred for 5 hours, and finally pure water is added dropwise to precipitate the product, thereby completing the hydrolysis reaction to generate the bis(3-methylthio)-3,6-diphenylcarbazole butyl phosphate.

[0167] The self-assembled hole transport material obtained in Example 7 is bis(3-methylthio)-3,6-diphenylcarbazole butyl phosphate (denoted as 4P-6), and the structure of the compound is:

[0168]

[0169] Figure 7 This is a graph showing the test results of the hydrogen nuclear magnetic resonance spectrometer of bis(3-methylthio)-3,6-diphenylcarbazole butyl phosphate obtained in Example 7. It can be seen from the graph that the structure of the obtained compound is correct.

[0170] Control group 1

[0171] This control group uses carbazole butyl phosphate (CAS: 20999-36-4) as a hole transport material, and its structure is:

[0172]

[0173] Control group 2

[0174] This control group uses 3,6-diphenylcarbazole butyl phosphate (CAS: 2814500-04-2) as a hole transport material, and its structure is:

[0175]

[0176] Application Example 1

[0177] This application example provides a hole transport layer, which is composed of the hole transport materials obtained in Examples 1-7 and Control Groups 1-2, respectively. The preparation method of the hole transport layer includes:

[0178] The hole transport materials obtained in the example and the control group were respectively prepared into a precursor solution with a concentration of 1 mg / mL in solvents of N,N-dimethylformamide and dimethyl sulfoxide. The precursor solution was spin-coated at 3000 rpm for 30 seconds to form a film, and then annealed at 100° C. for 10 minutes to obtain a hole transport layer with a thickness of 2 to 5 nm.

[0179] Figures 8 to 16 The contact angle test results of the hole transport layer made of the hole transport materials obtained in Examples 1-7 and Control Groups 1-2 on the perovskite solution are shown in the figure. It can be seen from the figure that the contact angles are 3,6-diphenylcarbazole butyl phosphate (CA=17.08) obtained in Control Group 2, carbazole butyl phosphate (CA=16.53) obtained in Control Group 1, bis(4-cyano)-3,6-diphenylcarbazole butyl phosphate (CA=15.18) obtained in Example 3, bis(4-methoxy)-3,6-diphenylcarbazole butyl phosphate (CA=14.70) obtained in Example 7. The hole transport layer prepared from bis(3-methylthio)-3,6-diphenylcarbazole butyl phosphate (12.24), bis(4-formylamino)-3,6-diphenylcarbazole butyl phosphate obtained in Example 4 (CA=12.16), bis(4-methylthio)-3,6-diphenylcarbazole ethyl phosphate (11.8) obtained in Example 6, bis(4-methylthio)-3,6-diphenylcarbazole butyl phosphate (CA=11.14) obtained in Example 2, and bis(4-carboxyl)-3,6-diphenylcarbazole butyl phosphate (CA=10.42) obtained in Example 5, the smaller the contact angle, the higher the wettability.

[0180] Application Example 2

[0181] This application example provides a perovskite solar cell, comprising a conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer and an electrode stacked in sequence; wherein the conductive substrate is FTO conductive glass, and the thickness of the FTO film is 550nm; the hole transport layer is the hole transport layer obtained in application example 1; the perovskite material of the perovskite layer is MA x FA 1-x CxP3-a Br a , the structural formula of MA is CH3NH3 + , the structural formula of FA is CH(NH2)2 + ; The thickness of the perovskite layer is 460nm; the electron transport layer is PCBM, with a thickness of 20nm; the electrode is Ag, with a thickness of 120nm.

[0182] The obtained perovskite solar cell was tested, and the results are shown in Table 1.

[0183] Table 1

[0184]

[0185] Note: In Table 1, Voc represents open circuit voltage, Jsc represents short circuit current, FF represents fill factor, and η represents conversion efficiency.

[0186] From the above, it can be seen that the efficiency of perovskite solar cells with hole transport materials containing methoxyphenyl, methylthiophenyl, cyanophenyl, carboxyphenyl, and formylaminophenyl is significantly better than that of ordinary small molecule hole transport materials, mainly reflected in the improvement of voltage and filling factor. The increase in voltage indicates that the hole transport material has a better energy level match with the perovskite, and the increase in filling factor indicates that the perovskite has a better interaction force with the hole transport material. The introduction of the above functional groups can improve the wettability of the perovskite, and at the same time, complex with the perovskite component to passivate the interface under the perovskite layer, thereby improving the efficiency of the device.

[0187] In summary, the method of the present invention adopts four steps to synthesize and prepare five types of self-assembled hole transport materials, and the legal method is simple, the yield is high, and it is suitable for mass production. Specifically, the preparation method of the present invention can avoid the use of expensive raw materials, and the third step is to use the bromine carbazole substituent coupling substitution reaction as the purpose, and then connect the hydrophilic group containing aromatic rings, considering that the carbazole containing methoxyphenyl, methylthiophenyl and other hydrophilic group substituents containing aromatic rings cannot be directly bought at a lower price on the market, so the present invention is also equivalent to providing a method for introducing a hydrophilic functional group containing aromatic rings at the upper end of carbazole. If the first step in the present invention uses carbazole containing methoxyphenyl, methylthiophenyl and other hydrophilic substituents containing aromatic rings or dibromocarbazole in the first step first carries out coupling substitution reaction, then the synthetic route of each final product requires at least three or four completely different reaction nodes, thereby causing cost increase, and causing yield and production schedule to be affected. The self-assembled hole transport material obtained by the preparation method can improve the hydrophilicity and optimize the passivation of the lower interface of the perovskite, thereby helping to further improve the conversion efficiency and stability of the perovskite battery.

[0188] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. In addition, the various different embodiments of the present invention can also be arbitrarily combined, as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a self-assembled hole transport material, characterized in that: The preparation method comprises: (1) mixing the raw material compound VIII with the raw material compound VII, and carrying out an alkylation reaction under the action of a strong base and a phase transfer catalyst to produce an intermediate compound VI; Where n is an integer between 2 and 6; X 11 , X 12 and X2 are each independently selected from any one of halogen; (2) mixing the intermediate compound VI with the raw material compound V or the raw material compound V' to carry out a substitution reaction to generate the intermediate compound IV; Wherein, L is selected from any one of C2 to C4 straight chain alkyl groups; (3) mixing the intermediate compound IV with the raw material compound IIIa and the raw material compound IIIb in a solvent, and performing a coupling reaction under the action of an alkaline substance and a coupling catalyst to produce the intermediate compound II; Among them, R 11 and R 12 Each is independently selected from any one of the following groups: m1, m2, m3, m4 and m5 are each independently selected from integers between 1 and 5; the dotted line represents the attachment site of the group; (4) subjecting the intermediate compound II to a hydrolysis reaction to generate a self-assembled hole transport material having a structure as shown in Formula I; 2. The method for preparing the self-assembled hole transport material according to claim 1, characterized in that: In step (1), the raw material compound VIII includes a compound having the following structure: Preferably, it is any one of 1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane, 1,5-dibromopentane or 1,6-dibromohexane; Preferably, the raw material compound VII is 3,6-dibromocarbazole or 3,6-dichlorocarbazole; Preferably, the strong base comprises potassium hydroxide and / or sodium hydroxide; Preferably, the strong base is an aqueous solution with a concentration of 20% to 60%; Preferably, the phase transfer catalyst comprises tetrabutylammonium bromide and / or tetrabutylammonium iodide; Preferably, the alkylation reaction is carried out under reflux and stirring under a protective atmosphere; Preferably, the temperature of the alkylation reaction is 20 to 70°C; Preferably, the alkylation reaction time is 8 to 16 hours, so that the yield of the intermediate compound VI is ≥ 90%; Preferably, the intermediate compound VI is any one of 3,6-dibromocarbazole ethyl bromide, 3,6-dibromocarbazole propyl bromide, 3,6-dibromocarbazole butyl bromide, 3,6-dibromocarbazole pentyl bromide or 3,6-dibromocarbazole hexyl bromide.

3. The method for preparing the self-assembled hole transport material according to claim 1 or 2, characterized in that: In step (2), the raw material compound V is triethyl phosphite, and the raw material compound V' is diethyl phosphite; Preferably, the substitution reaction is carried out under reflux and stirring in a protective atmosphere; Preferably, the substitution reaction time is 12 to 36 hours, so that the yield of the intermediate compound IV is ≥ 95%; Preferably, the intermediate compound IV is any one of 3,6-dibromocarbazole ethylphosphonic acid diethyl ester, 3,6-dibromocarbazole propylphosphonic acid diethyl ester, 3,6-dibromocarbazole butylphosphonic acid diethyl ester, 3,6-dibromocarbazole pentylphosphonic acid diethyl ester or 3,6-dibromocarbazole hexylphosphonic acid diethyl ester.

4. The method for preparing the self-assembled hole transport material according to any one of claims 1 to 3, characterized in that: In step (3), the raw material compound IIIa and the raw material compound IIIb are any one of 4-methoxyphenylboronic acid, 4-methylthiophenylboronic acid, 4-cyanophenylboronic acid, 4-formylaminophenylboronic acid or 4-carboxyphenylboronic acid; Preferably, the starting compound IIIa is the same as the starting compound IIIb; Preferably, the solvent comprises N,N-dimethylacetamide and / or tetrahydrofuran; Preferably, the alkaline substance comprises potassium carbonate and / or sodium carbonate; Preferably, the coupling catalyst comprises tetrakis(triphenylphosphine)palladium and / or palladium acetate; Preferably, the coupling reaction is carried out under reflux and stirring under a protective atmosphere; Preferably, the coupling reaction temperature is 70 to 180°C, preferably 160 to 180°C; Preferably, the coupling reaction time is 18 to 30 hours, so that the yield of the intermediate compound II is ≥80%; Preferably, the intermediate compound II is bis(4-methoxy)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-methylthio)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-cyano)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-carboxyl)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-formylamino)-3,6-diphenylcarbazoleethyl diethyl phosphate, bis(4-methoxy)-3,6-diphenylcarbazolepropyl diethyl phosphate bis(4-methylthio)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-cyano)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-carboxyl)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-formylamino)-3,6-diphenylcarbazole propyl diethyl phosphate, bis(4-methoxy)-3,6-diphenylcarbazole butyl diethyl phosphate, bis(4-methylthio)-3,6-diphenylcarbazole butyl diethyl phosphate, bis(4-cyano)- 3,6-diphenylcarbazole butyl diethyl phosphate, bis(4-carboxyl)-3,6-diphenylcarbazole butyl diethyl phosphate, bis(4-formylamino)-3,6-diphenylcarbazole butyl diethyl phosphate, bis(4-methoxy)-3,6-diphenylcarbazole pentyl diethyl phosphate, bis(4-methylthio)-3,6-diphenylcarbazole pentyl diethyl phosphate, bis(4-cyano)-3,6-diphenylcarbazole pentyl diethyl phosphate, bis(4-carboxyl)-3,6-diphenylcarbazole pentyl phosphate any one of bis(4-formylamino)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-methoxy)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-methylthio)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-cyano)-3,6-diphenylcarbazole hexyl phosphate diethyl ester, bis(4-carboxy)-3,6-diphenylcarbazole hexyl phosphate diethyl ester or bis(4-formylamino)-3,6-diphenylcarbazole hexyl phosphate diethyl ester.

5. The method for preparing the self-assembled hole transport material according to any one of claims 1 to 4, characterized in that: In step (4), the hydrolysis reaction is carried out under a protective atmosphere with stirring at room temperature; Preferably, the hydrolysis reaction includes a hydrolysis aid, and the hydrolysis aid includes trimethylsilyl bromide; Preferably, the hydrolysis reaction comprises an auxiliary solvent, and the auxiliary solvent comprises 1,4-dioxane and / or dichloromethane; Preferably, the self-assembled hole transport material having the structure shown in Formula I comprises a compound having the following structure:

6. A hole transport layer, characterized in that: A self-assembled hole transport material obtained by the preparation method according to any one of claims 1 to 5.

7. A method for preparing a hole transport layer according to claim 6, characterized in that: The self-assembled hole transport material is prepared into a precursor solution, the precursor solution is used to form a film, and then annealed to obtain the hole transport layer.

8. The method for preparing a hole transport layer according to claim 7, characterized in that: The solvent in the precursor solution includes at least one of methanol, ethanol, isopropanol, N,N-dimethylformamide, dimethyl sulfoxide or N-methylpyrrolidone; Preferably, the concentration of the self-assembled hole transport material in the precursor solution is 0.1 to 5 mg / mL; Preferably, the film forming method includes at least one of spin coating, spray coating, blade coating or dip coating; Preferably, the annealing temperature is 100-120°C; Preferably, the hole transport layer has a thickness of 10 to 200 nm.

9. A battery assembly, characterized in that: A hole transport layer comprising the hole transport layer according to claim 6, or a hole transport layer obtained by the preparation method according to claim 7 or 8.

10. The battery assembly according to claim 9, characterized in that: The battery assembly includes a conductive substrate, the hole transport layer, the perovskite layer, the electron transport layer and an electrode; Preferably, the conductive substrate comprises any one of FTO conductive glass, ITO conductive glass, FTO conductive plastic or ITO conductive plastic; wherein the thickness of the FTO film layer is 500-600 nm, and the thickness of the ITO film layer is 300-400 nm; Preferably, the perovskite material of the perovskite layer comprises MA x FA 1-x CxP 3-a Br a 、MA y FA 1-y CxP 3-b Cl b 、MA z FA 1-z Cb 3-c Cl c , wherein x, y and z are each independently selected from 0 to 1, a, b and c are each independently selected from 0 to 3, and the structural formula of MA is CH3NH3 + , the structural formula of FA is CH(NH2)2 + ; Preferably, the thickness of the perovskite layer is 300 to 1000 nm; Preferably, the electron transport layer comprises any one of SnO2, TiO2, ZnO, Al2O3, fullerene and derivatives thereof; Preferably, the thickness of the electron transport layer is 10 to 50 nm; Preferably, the electrode comprises any one of Ag, Al, Au, IWO or ITO; Preferably, the thickness of the electrode is 100-200 nm.

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