Hole transport layer compound, hole transport layer, photovoltaic device and preparation method

Abstract

The invention belongs to the photovoltaic field, and particularly relates to a hole transport layer compound, a hole transport layer, a photovoltaic device and a preparation method. The hole transport layer compound disclosed by the invention has a structure as shown in a formula I, wherein the definitions of X1, X2, A and L are described in the specification. The hole transport layer compound provided by the invention is an acridine derivative, has better film forming uniformity as a hole transport material, can improve the performance of a large-size perovskite photovoltaic device, and has very high commercial application prospects. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and in particular relates to a hole transport layer compound, a hole transport layer, a photovoltaic device and a preparation method. Background Art

[0002] Thanks to advances in perovskite film formation and materials technology, the photoelectric conversion efficiency of perovskite solar cells has increased from 3.8% to over 26% over the past decade. Currently, the development of efficient, stable, and low-cost charge transport materials, particularly hole transport materials (HTMs), is crucial to the commercialization of perovskite solar cells (PSCs).

[0003] Recently, an anchoring-based self-assembly strategy has been demonstrated to enable the construction of efficient hole transport layers for high-performance pin-structured PSCs. This process employs self-assembling molecules as HTMs, which include anchoring groups (e.g., carboxyl groups) that can spontaneously adsorb onto the surface of an oxide substrate to form a monolayer coverage. Compared with conventional thick hole transport layers (HTLs) obtained by spin coating or spray pyrolysis, self-assembled monolayers (SAMs) have the advantages of minimal material consumption and low parasitic absorption. Furthermore, the chemical bath deposition-based approach is a low-cost and scalable process route that has been successfully applied to small modules as well as large-area perovskite-silicon tandem solar cells.

[0004] However, these self-assembled monolayers reported so far still suffer from issues such as insufficient stability and poor wettability. When prepared over large areas, they also suffer from poor uniformity, leading to leakage currents. This poses a significant obstacle to the effective application of self-assembled molecules as HTMs.

[0005] Derivatives of acridine phosphonate were reported in CN118702727A, CN116056531A and Nature 620, 545–551 (2023). The research on substituents on the acridine ring was limited to halogens and fatty chains. These materials had problems with wettability and uniformity when used to prepare large-area perovskite photovoltaic devices, and could not meet the requirements of large-size devices. Summary of the Invention

[0006] To solve the problems existing in the prior art, the present invention adopts the strategy of replacing acridine with aromatic groups to regulate the terminal functional groups of acridine derivatives to achieve the regulation of SAMs wettability and intermolecular interaction, thereby realizing large-area uniform preparation of SAMs.

[0007] Specifically, the present invention provides a compound of formula I:

[0008]

[0009] In Formula I,

[0010] X1 and X2 are independently selected from unsubstituted or substituted phenyl and unsubstituted or substituted 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S, the substituents on the phenyl and the 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S are each independently selected from C1-C4 alkyl, L is selected from C1-C12 alkylene and C6-C14 arylene, and A is a phosphate group or a carboxylic acid group.

[0011] In one or more embodiments, the number of substituents on the phenyl group and the 5-14 membered heteroaryl group having 1, 2 or 3 heteroatoms selected from N, O, Se and S can be 1, 2, 3, 4 or 5.

[0012] In one or more embodiments, the 5-14 membered heteroaryl group having 1, 2 or 3 heteroatoms selected from N, O, Se and S is furyl, thienyl, pyrrolyl, pyridyl or carbazolyl.

[0013] In one or more embodiments, the C6-C14 arylene group is phenylene, naphthylene, and anthracene.

[0014] In one or more embodiments, X1 and X2 are independently selected from unsubstituted or substituted phenyl, unsubstituted or substituted furyl, unsubstituted or substituted thienyl, unsubstituted or substituted pyrrolyl, unsubstituted or substituted pyridinyl, and unsubstituted or substituted carbazolyl.

[0015] In one or more embodiments, X1 and X2 are each independently selected from phenyl, furyl, and thienyl.

[0016] In one or more embodiments, X1 and X2 are each independently selected from phenyl, furan-2-yl, and thiophen-2-yl.

[0017] In one or more embodiments, X1 and X2 are the same or different.

[0018] In one or more embodiments, L is selected from C1-C12 alkylene, phenylene, naphthylene, and anthracene.

[0019] In one or more embodiments, L is selected from C1-C8 alkylene and phenylene.

[0020] In one or more embodiments, L is selected from C2-C4 alkylene and phenylene.

[0021] In one or more embodiments, A is a phosphate group.

[0022] In one or more embodiments, the compound of formula I is selected from the following compounds SAM1-SAM9:

[0023]

[0024] Another aspect of the present invention provides a hole transport layer precursor solution, wherein the hole transport layer precursor solution comprises the compound of formula I described in any embodiment of the present invention and a solvent.

[0025] In one or more embodiments, the solvent is an alcohol solvent, a combination of an alcohol solvent and N,N-dimethylformamide, or a combination of an alcohol solvent and dimethyl sulfoxide.

[0026] In one or more embodiments, in the hole transport layer precursor solution, the mass of the compound of formula I is 0.1-5.0 mg per milliliter of solvent.

[0027] Another aspect of the present invention further provides a hole transport layer, wherein the hole transport layer comprises the compound of formula I described in any embodiment of the present invention.

[0028] In one or more embodiments, the hole transport layer has a thickness of 0.1-10 nm.

[0029] Another aspect of the present invention provides a method for preparing a hole transport layer, the method comprising coating the hole transport layer precursor solution described in any embodiment of the present invention, and then annealing to obtain the hole transport layer.

[0030] In one or more embodiments, the annealing method is heating annealing, the annealing temperature is 50-150° C., and the annealing time is 1-30 min.

[0031] In one or more embodiments, the annealing method is heating annealing, the annealing temperature is 80-120° C., and the annealing time is 5-15 minutes.

[0032] Another aspect of the present invention further provides a photovoltaic device, comprising a first hole transport layer, wherein the first hole transport layer is the hole transport layer described in any embodiment of the present invention.

[0033] In one or more embodiments, the photovoltaic device comprises, in order, a conductive substrate, a first hole transport layer, a perovskite light absorbing layer, an electron transport layer, and an electrode.

[0034] In one or more embodiments, the electron transport layer comprises one or more of [6,6]-phenyl-C61-butyric acid methyl ester, C60, and tin oxide.

[0035] In one or more embodiments, a hole blocking layer is further provided between the electron transport layer and the electrode.

[0036] In one or more embodiments, the hole blocking layer includes one or two of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, zirconium acetylacetonate, and tin oxide.

[0037] In one or more embodiments, a second hole transport layer is further provided between the first hole transport layer and the conductive substrate, and the second hole transport layer is an inorganic hole transport layer.

[0038] In one or more embodiments, the raw materials of the perovskite light-absorbing layer include a first perovskite material and a second perovskite material, wherein the first perovskite material is one or more selected from lead halide salts and tin halide salts, and the second perovskite material is one or more selected from formamidine halide salts, methylamine halide salts and cesium halide salts.

[0039] In one or more embodiments, the electrode is selected from one or more of a silver electrode, a copper electrode, a conductive oxide electrode, and a carbon electrode.

[0040] In one or more embodiments, the photovoltaic device is a perovskite solar cell.

[0041] In one or more embodiments, the perovskite solar cell is a single-junction perovskite cell, a crystalline silicon-perovskite tandem cell, a perovskite-perovskite tandem cell, a perovskite-copper indium gallium selenide tandem cell, or a perovskite-gallium arsenide tandem cell.

[0042] Compared to groups such as halogens and aliphatic chains, the acridine derivative hole transport materials provided by the present invention use aromatic substituents. The introduction of aromatic groups enhances the π-π interactions between SAMs molecules, thereby forming a more dense and uniform hole transport layer and reducing direct contact between the perovskite layer and the substrate. Simultaneously, the Coulombic interaction between the π electrons in the aromatic ring and the perovskite metal cations can passivate the defects of the perovskite bottom interface, improving the film quality of the perovskite layer and overcoming the problem of low-quality perovskite films caused by poor wettability of the perovskite precursor solution on the SAMs layer. Compared to the existing commercial SAMs material [4-(3,6-dimethyl-9H-carbazol-9-yl)butyl] phosphate (Me-4PACz), the acridine derivative provided by the present invention has better film uniformity as a hole transport material and can improve the performance of large-scale perovskite photovoltaic devices by approximately 2 percentage points, showing very high commercial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the structure of a PIN-type perovskite solar cell in some embodiments of the present invention.

[0044] Figure 2 This is the NMR spectrum of compound SAM1.

[0045] Figure 3 1 is an IV curve diagram of the device of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0046] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0047] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0048] Herein, “comprising,” “including,” “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of,” for example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to have been disclosed herein.

[0049] Throughout this document, all features, such as values, amounts, amounts, and concentrations, specified in numerical ranges or percentage ranges are provided for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to encompass and specifically disclose all possible subranges and individual values ​​within those ranges (including integers and fractions).

[0050] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0051] Herein, when describing embodiments or examples, it should be understood that they are not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described herein are encompassed within the scope defined by the claims.

[0052] In this document, for the sake of brevity, not all possible combinations of the various technical features in each embodiment or example are described. Therefore, as long as there are no contradictions in the combination of these technical features, the various technical features in each embodiment or example can be combined in any way, and all possible combinations should be considered to be within the scope of this specification.

[0053] Herein, aromatic groups include aryl groups and heteroaryl groups.

[0054] The present invention provides a compound of formula I that can be used as a hole transport layer material:

[0055]

[0056] In Formula I,

[0057] X1 and X2 are independently selected from unsubstituted or substituted phenyl and unsubstituted or substituted 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S, and the substituents on the phenyl and 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S are independently selected from C1-C4 alkyl. Preferably, the 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S is furyl, thienyl, pyrrolyl, pyridyl or carbazolyl;

[0058] L is selected from C1-C12 alkylene and C6-C14 arylene, preferably, the C6-C14 arylene is phenylene, naphthylene and anthracene;

[0059] A is a phosphate group or a carboxylic acid group.

[0060] Compared to X1 and X2 being halogen or aliphatic chain substituents, the present invention introduces aromatic substituents as X1 and X2 into the compound of formula I, which can enhance the π-π interaction between the molecules of the compound of formula I, thereby forming a more dense and uniform hole transport layer. At the same time, the Coulomb interaction between the π electrons of the aromatic ring and the perovskite metal cation can effectively improve the film quality of the perovskite layer, overcoming the defect of poor wettability of traditional SAMs molecules. Therefore, the compound of formula I of the present invention, in which X1 and X2 are aromatic substituents, can provide large-area perovskite solar cell devices with better photovoltaic performance.

[0061] In the present invention, substitution refers to the replacement of hydrogen atoms on a compound or group by a substituent. The number of substituents does not exceed the number of replaceable hydrogen atoms on the compound or group.

[0062] In the present invention, X1 and X2 may be the same or different. In some embodiments, X1 and X2 are the same.

[0063] In some preferred embodiments, X1 and X2 are independently selected from phenyl, furanyl and thienyl, for example, X1 and X2 can be independently selected from phenyl, furan-2-yl and thien-2-yl.

[0064] In some preferred embodiments, L is selected from C1-C8 alkylene (e.g., C1 alkylene, C2 alkylene, C3 alkylene, C4 alkylene, C5 alkylene, C6 alkylene, C7 alkylene, C8 alkylene) and phenylene (e.g., 1,4-phenylene). In some embodiments, L is selected from C2-C4 alkylene and phenylene.

[0065] In some preferred embodiments, A is a phosphate group (-PO(OH)2).

[0066] In some preferred embodiments, the compound of formula I is selected from the following compounds SAM1-SAM9:

[0067]

[0068] The compound of formula I of the present invention can be synthesized by the following general synthetic route:

[0069] Step S1: 2,7-dibromo-9,9-dimethylacridine and the corresponding aromatic boronic acid compound are mixed, potassium carbonate, tetrakistriphenylphosphine palladium, and a mixed solvent of 1,4-dioxane and water are added, the temperature is raised to about 100° C., and an aromatic substituted acridine intermediate a is obtained by Suzuki coupling;

[0070] Step S2: mixing the aromatic-substituted acridine intermediate a obtained in step S1 with a dibromoalkane, adding potassium hydroxide solution, and reacting at about 65° C. to prepare intermediate b; or mixing intermediate a with p-bromoiodobenzene (or bromine- and iodine-substituted naphthalene, or bromine- and iodine-substituted anthracene), and performing an Ullmann reaction under the catalysis of cuprous iodide to prepare intermediate b;

[0071] Step S3: mixing intermediate b with triethyl phosphite and reacting at about 150° C. to prepare the corresponding phosphate intermediate c;

[0072] Step S4: Dissolve the intermediate c in an organic solvent, react with trimethylsilyl bromide at room temperature for about 12 hours, then add methanol and water, and the reaction product after hydrolysis is precipitated and filtered to obtain the corresponding compound of formula I.

[0073] In some embodiments, A is a carboxyl group (-COOH), and the compound of formula I can be synthesized by the following general synthetic route:

[0074] Step S1: 2,7-dibromo-9,9-dimethylacridine and the corresponding aromatic boronic acid compound are mixed, potassium carbonate, tetrakistriphenylphosphine palladium, and a mixed solvent of 1,4-dioxane and water are added, the temperature is raised to about 100° C., and an aromatic substituted acridine intermediate a is obtained by Suzuki coupling;

[0075] Step S2: Mix the aryl-substituted acridine intermediate a with ethyl 4-bromobenzoate or ethyl bromoalkylcarboxylate, add tri-tert-butylphosphine tetrafluoroborate, tris(dibenzylideneacetone)dipalladium, sodium tert-butoxide, and anhydrous toluene, and reflux at 110°C for 12 hours under a nitrogen atmosphere. Extract with dichloromethane, dry over anhydrous sodium sulfate, concentrate with rotary evaporation, and purify with column chromatography to obtain the carboxylate intermediate b.

[0076] Step S3: dissolve the carboxylate intermediate b in tetrahydrofuran, add lithium hydroxide aqueous solution dropwise, react at 80°C for 12 h, remove the tetrahydrofuran by rotary evaporation, add dilute hydrochloric acid dropwise until the product precipitates, filter and dry to obtain the compound of formula I.

[0077] The present invention provides a method for preparing a hole transport layer, which comprises dispersing a compound of formula I in a solvent, stirring uniformly to obtain a hole transport layer precursor solution, coating the hole transport layer precursor solution, and then annealing to obtain the hole transport layer.

[0078] In the present invention, in the hole transport layer precursor solution, the mass of the compound of formula I per milliliter of solvent is preferably 0.1-5.0 mg, for example, 0.2 mg, 0.3 mg, 0.4 mg, 0.5 mg, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1.0 mg, 1.2 mg, 1.4 mg, 1.6 mg, 1.8 mg, 2.0 mg, 2.2 mg, 2.4 mg, 2.6 mg, 2.8 mg, 3.0 mg, 3.2 mg, 3.4 mg, 3.6 mg, 3.8 mg, 4.0 mg, 4.2 mg, 4.4 mg, 4.6 mg, and 4.8 mg.

[0079] The hole transport layer can be obtained by applying the hole transport layer precursor solution of the present invention and then annealing. The annealing method can be heating annealing. The annealing temperature is preferably 50-150°C, for example, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, more preferably 80-120°C. The annealing time is preferably 1-30 min, for example, 2 min, 4 min, 6 min, 8 min, 10 min, 12 min, 14 min, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, more preferably 5-15 min.

[0080] The thickness of the hole transport layer of the present invention is preferably 0.1-10 nm, for example 0.2 nm, 0.3 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm.

[0081] In the present invention, the raw materials of the perovskite structure material can be AX and BX2, and the A ion is a monovalent cation, including but not limited to cesium ions (Cs + ), rubidium ions (Rb + ), methylamine ion (CH3NH3 + , MA + ) and formamidinium ion (CH(NH2)2 + , FA +) one or more; B ion is a divalent cation, which may include but is not limited to lead ion (Pb 2+ ) and / or tin ions (Sn 2+ ); X ion is a monovalent anion, which may include but is not limited to fluoride ion (F - ), iodide ion (I - ), bromide ion (Br - ), chloride ion (Cl - ) and cyanate ion (SCN - ) or more. Preferably, in the raw materials for the perovskite structure material, the A ion is selected from one or more of cesium ions, methylamine ions, and formamidine ions; the B ion is lead ions and / or tin ions; and the X ion is iodide ions and / or bromide ions. In some embodiments, the raw materials for the perovskite structure material are PbI2 and MAI.

[0082] In some embodiments, the chemical formula of the perovskite structure material of the present invention is ABX3; the A ion can be one or more selected from formamidine ion, cesium ion, cesium ion and rubidium ion; the B ion can be one or two selected from lead ion and tin ion; the X ion can be one or more selected from F - , I - Br - 、Cl - and SCN - One or more of .

[0083] The electron transport layer of the present invention can be selected from n-type single crystal silicon, n-type polycrystalline silicon, n-type amorphous silicon, TiO2, SnO2, ZnO, ZrO2, GZO, IZO, FTO, ITO, BaSnO3, TiSnO x 、SnZnO x , one or more of fullerenes (such as C60 and C70) and fullerene derivatives (such as PCBM).

[0084] The electrode of the present invention can be one or more materials selected from Au, Ag, Al, Cu, graphene, TCO materials and nanocrystalline silicon. The electrode preparation methods include but are not limited to one or more of spin coating, blade coating, evaporation, printing, spray coating, spray pyrolysis and slot coating.

[0085] The present invention provides a perovskite solar cell comprising a hole transport layer of the present invention. In the present invention, the perovskite solar cell may include a single-junction perovskite solar cell or a tandem perovskite solar cell; the perovskite solar cell may include a formal perovskite solar cell (NIP-type perovskite solar cell) or an inverted perovskite solar cell (PIN-type perovskite solar cell). Specifically, the perovskite solar cell may be a formal single-junction perovskite solar cell, an inverted single-junction perovskite solar cell, or a tandem perovskite solar cell.

[0086] In the present invention, a formal single-junction perovskite solar cell may include, in sequence, a transparent conductive substrate, an electron transport layer, a perovskite light absorbing layer, a hole transport layer, and a metal electrode. In the present invention, an inverted single-junction perovskite solar cell may include, in sequence, a transparent conductive substrate, a hole transport layer, a perovskite light absorbing layer, an electron transport layer, a hole blocking layer, and a metal electrode. In the present invention, a tandem perovskite solar cell may include, in sequence, a bottom electrode, a bottom cell, a tunneling layer, a perovskite top cell, and a top electrode. The perovskite top cell may include, in sequence, a hole transport layer, a perovskite light absorbing layer, and an electron transport layer.

[0087] In some embodiments, as Figure 1 As shown, the pin-type perovskite solar cell includes a metal electrode, an electron transport layer, a perovskite layer (i.e., a perovskite light absorbing layer), a hole transport layer, and a conductive glass. In some embodiments, the pin-type perovskite solar cell further includes a hole blocking layer located between the electrode and the electron transport layer.

[0088] The present invention will be described below by way of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the examples are, unless otherwise stated, conventional methods, reagents, and materials in the art. The starting compounds in the examples can all be purchased from commercial sources.

[0089] Synthesis example 1

[0090]

[0091] Step 1: 2,7-Dibromo-9,9-dimethylacridine (2.20 g, 6 mmol), phenylboronic acid (1.83 g, 15 mmol), tetrakistriphenylphosphine palladium (280 mg, 0.24 mmol), and potassium carbonate (3.40 g, 24.6 mmol) were added to a mixed solvent of 1,4-dioxane (50 mL) and water (10 mL). The mixture was mixed and refluxed at 100°C for 12 hours. After completion of the reaction, the mixture was extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by silica gel column chromatography (petroleum ether:dichloromethane = 5:1, v / v) to obtain 1.50 g of a white solid, intermediate S1a (yield 69%).

[0092] Step 2: S1a (0.8 g, 2.2 mmol) was added to 20 mL of 1,4-dibromobutane, followed by 5 mL of 50% potassium hydroxide solution. The mixture was heated to 65°C and reacted for 12 hours. After completion of the reaction, the mixture was extracted with dichloromethane, dried over anhydrous sodium sulfate, and purified by silica gel column chromatography (petroleum ether:dichloromethane = 10:1 to 3:1, v / v) to obtain 0.99 g of a white foamy solid, intermediate S1b (yield 91%).

[0093] Step 3: Dissolve S1b (0.99 g, 1.98 mmol) in 10 mL of triethyl phosphite, heat to 150°C, and stir for 12 hours. After the reaction, remove the excess triethyl phosphite by rotary evaporation and purify by silica gel column chromatography (petroleum ether: dichloromethane = 1:1 to 0:1, v / v) to obtain 989 mg of light yellow viscous intermediate S1c (yield 90%).

[0094] Step 4: S1c (989 mg, 1.98 mmol) was added to 20 mL of 1,4-dioxane, and trimethylsilyl bromide (2.73 g, 17.8 mmol) was added. The mixture was reacted at room temperature for 12 hours, and then the organic solvent was removed by rotary evaporation. 15 mL of methanol was added, and deionized water was added dropwise until a white solid precipitated. The white solid SAM1 was obtained by filtration. 641 mg, 65% yield.

[0095] The NMR spectrum of SAM1 is as follows Figure 2 shown.

[0096] The NMR spectrum of SAM1 is: 1 H NMR(400MHz,DMSO-d6)δ7.72(d,J=2.2Hz,2H),7.70–7.65(m,4H),7.53(dd,J=8.5,2.1Hz,2H),7.45(t,J=7.6Hz,4H),7 .31(t,J=7.3Hz,2H),7.19(dd,J=8.7,1.9Hz,2H),4.03(t,J=7.4Hz,2H),1.88(m,2H),1.79–1.64(m,4H),1.62(s,6H).

[0097] Synthesis example 2

[0098] The synthesis method of SAM4 is similar to that of SAM1, except that phenylboronic acid is replaced with an equimolar amount of thiophene-2-boronic acid in step 1.

[0099] SAM4 It is a white solid.

[0100] The NMR spectrum of SAM4 is: 1 H NMR (400MHz, DMSO-d6) δ7.59(dd,J=5.0,1.9Hz,2H),7.55(dd,J=6.2,1.7Hz,2H),7.48(dd,J=11.8,2.1Hz,2H),7.33(dd,J=6.3,2 .1Hz,2H),7.17(dd,J=6.1,5.1Hz,2H),7.03(d,J=6.3Hz,2H),4.05(t,J=7.4Hz,2H),1.89(m,2H),1.81–1.66(m,4H),1.60(s,6H).

[0101] Synthesis example 3

[0102] The synthesis method of SAM7 is similar to that of SAM1, except that in step 1, phenylboronic acid is replaced with an equimolar amount of furan-2-boronic acid.

[0103] SAM7 It is a white solid.

[0104] The NMR spectrum of SAM7 is: 1 H NMR (400MHz, DMSO-d6) δ7.76(t,J=1.5Hz,2H),7.74(dd,J=6.7,2.1Hz,2H),7.52(dd,J=2.0,1.0Hz,2H),7.03(d,J=6.8Hz,2H) ,7.01(dd,J=4.9,1.8Hz,2H),6.74(dd,J=4.8,1.2Hz,2H),4.04(t,J=7.4Hz,2H),1.88(m,2H),1.80–1.64(m,4H),1.61(s,6H).

[0105] Synthesis example 4

[0106] The synthesis method of SAM3 is similar to that of SAM1, except that in step 2, 1,4-dibromobutane is replaced with 2.0 molar equivalents of 4-bromoiodobenzene, and intermediate S3b is prepared by Ullmann reaction (reaction temperature 100°C, time 12 hours) catalyzed by 0.1 molar equivalents of cuprous iodide.

[0107] SAM3 It is a white solid.

[0108] The NMR spectrum of SAM3 is: 1H NMR (400MHz, DMSO-d6) δ7.68(d,J=7.9Hz,2H),7.64(dd,J=8.1,1.4Hz,6H),7.61(dd,J=6.7,2.1Hz ,3H),7.52–7.43(m,8H),7.42–7.36(m,3H),7.15–7.11(m,5H),7.04(d,J=6.8Hz,3H),1.60(s,6H).

[0109] Example 1

[0110] In this embodiment, a PIN-type perovskite solar cell is prepared in the order of a conductive substrate, a hole transport layer, a perovskite light absorbing layer, an electron transport layer, a hole blocking layer, and an electrode. The specific steps are as follows:

[0111] (1) The TCO conductive glass was ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol for 15 minutes respectively, and finally dried in a drying oven at 75°C for later use; the dried TCO conductive glass substrate was placed in a UV ozone machine for 25 minutes to remove organic impurities on its surface and optimize its surface wettability;

[0112] (2) Disperse 1 mg of SAMs material (SAM1) in 1 mL of ethanol solution; ultrasonicate for 20 min to obtain a hole transport material dispersion; take 30 μL of the above dispersion and drop it onto TCO conductive glass, spin-coat at 5000 rpm for 30 s, and then place the TCO conductive glass on a hot plate and heat anneal at 100 °C for 10 min to obtain a hole transport layer with a thickness of 1 nm;

[0113] (3) Dissolve 722.08 mg of lead iodide and 238.50 mg of iodomethylamine solid in 1 mL of N,N-dimethylformamide (DMF) and stir at room temperature until completely dissolved to obtain a perovskite precursor solution; in a nitrogen glove box, take 30 μL of the above perovskite precursor solution and drop it on the hole transport layer of the TCO conductive glass, first spin-coating at 1000 rpm for 10 seconds, then spin-coating at 5000 rpm for 30 seconds, and quickly add 125 μL of chlorobenzene at 5000 rpm for 25 seconds, then place the above TCO conductive glass on a hot plate and heat anneal at 100 °C for 40 minutes to form a perovskite light-absorbing layer with a thickness of 500 nm;

[0114] (4) Dissolve 20 mg of methanefullerene phenyl-C61-butyric acid methyl ester (PCBM) in 1 mL of chlorobenzene and stir at room temperature to obtain a [6,6]-phenyl-C61-butyric acid methyl ester solution; take 30 μL of the [6,6]-phenyl-C61-butyric acid methyl ester solution and drop it onto the perovskite light-absorbing layer of the TCO conductive glass. Spin-coat at 3000 rpm for 60 seconds and then anneal at 100°C for 5 minutes to obtain an electron transport layer with a thickness of 30 nm.

[0115] (5) Dissolve 0.5 mg of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) in 1 mL of isopropanol and stir at room temperature to obtain a hole blocking layer solution; add 40 μL of the hole blocking layer solution dropwise onto the electron transport layer and spin-coat at 5000 rpm for 35 s to obtain a hole blocking layer with a thickness of 6 nm;

[0116] (6) Transfer the TCO conductive glass forming the hole blocking layer, electron transport layer, perovskite light absorbing layer and hole transport layer into the vacuum coating instrument and wait until the vacuum degree is drawn to 3*10 -4 A silver electrode was evaporated at 500 Pa to form a silver electrode with a thickness of 100 nm on the hole blocking layer.

[0117] Example 2

[0118] The other conditions of this embodiment are the same as those of embodiment 1, with the only difference being that in step (2) of this embodiment, SAM1 is replaced with SAM4 of equal mass.

[0119] Example 3

[0120] The other conditions of this embodiment are the same as those of embodiment 1, with the only difference being that in step (2) of this embodiment, SAM1 is replaced with SAM7 of equal mass.

[0121] Example 4

[0122] The other conditions of this embodiment are the same as those of embodiment 1, with the only difference being that in step (2) of this embodiment, SAM1 is replaced with SAM3 of equal mass.

[0123] Comparative Example 1

[0124] The other conditions of this embodiment are the same as those of embodiment 1, except that in step (2) of this embodiment, SAM1 is replaced with Me-4PACz of equal mass.

[0125] Comparative Example 2

[0126] The other conditions of this embodiment are the same as those of embodiment 1, except that in step (2) of this embodiment, SAM1 is replaced with MeDMACPA of equal mass.

[0127] Comparative Example 3

[0128] The other conditions of this embodiment are the same as those of embodiment 1, except that in step (2) of this embodiment, SAM1 is replaced with DMACPA of equal quality.

[0129] Test Example 1

[0130] At 25°C, AM 1.5G standard solar spectrum, light intensity of 1000mW / cm 2 Under the condition of -0.10-20V, a solar simulator was used to determine the performance (open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency) of the solar cell modules in Examples 1-4 and Comparative Examples 1-3. The specific results are shown in Tables 1 and Figure 3 shown.

[0131] (1) Open circuit voltage (Voc): The voltage value corresponding to the current being zero.

[0132] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current per unit battery surface area is the short-circuit current density.

[0133] (3) Fill factor (FF): The ratio of the maximum output power (Pmax) of the battery to the product of the open circuit voltage and the short circuit current. The calculation formula is (Pmax / Voc*Isc), where the maximum power point is the point where the battery output power reaches its maximum value.

[0134] (4) Photoelectric conversion efficiency (PCE): Photoelectric conversion efficiency refers to the ratio of maximum output power to incident light power (Pin), and the calculation formula is (Pmax / Pin)*100%.

[0135] Table 1: Photovoltaic performance test results of solar cell modules of Examples 1-4 and Comparative Examples 1-3

[0136]

[0137] The effective area of ​​the photovoltaic device in Table 1 is 46.24 cm 2 , the number of sub-cells is 17 (obtained by laser scribing into sub-cells with a width of 3 to 5 mm). Figure 3It can be seen that, relative to Comparative Examples 2-3 (the hole transport layer material is a phosphonic acid acridinium derivative whose substituent is an alkyl or halogen), the compound of formula I provided by the present invention (a phosphonic acid acridinium derivative whose substituent is an aromatic group) is used as a hole transport layer material. The photovoltaic device as a whole has a higher open circuit voltage and fill factor. The reason is that the compound of formula I of the present invention can enhance the contact passivation between the hole transport layer and the bottom interface of the perovskite, while inducing the growth and crystallization of the perovskite layer to obtain a perovskite film with a low defect state density, thereby reducing the open circuit voltage loss, so that the corresponding photovoltaic device exhibits a higher open circuit voltage and photoelectric conversion efficiency.

Claims

1. Compound of formula I: In Formula I, X1 and X2 are independently selected from unsubstituted or substituted phenyl and unsubstituted or substituted 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S, and the substituents on the phenyl and the 5-14 membered heteroaryl having 1, 2 or 3 heteroatoms selected from N, O, Se and S are each independently selected from C1-C4 alkyl; L is selected from C1-C12 alkylene and C6-C14 arylene; A is a phosphate group or a carboxylic acid group.

2. The compound of formula I according to claim 1, wherein The compounds of formula I have one or more of the following characteristics: X1 and X2 are independently selected from unsubstituted or substituted phenyl, unsubstituted or substituted furyl, unsubstituted or substituted thienyl, unsubstituted or substituted pyrrolyl, unsubstituted or substituted pyridyl and unsubstituted or substituted carbazolyl; preferably, X1 and X2 are independently selected from phenyl, furyl and thienyl; more preferably, X1 and X2 are independently selected from phenyl, furan-2-yl and thien-2-yl; X1 and X2 are the same or different; L is selected from C1-C12 alkylene, phenylene, naphthylene and anthracene; preferably, L is selected from C1-C8 alkylene and phenylene; more preferably, L is selected from C2-C4 alkylene and phenylene; A is a phosphate group.

3. The compound of formula I according to claim 1, wherein The compound of formula I is selected from the following compounds SAM1-SAM9:

4. A hole transport layer precursor solution, characterized in that: The hole transport layer precursor solution comprises the compound of formula I according to any one of claims 1 to 3 and a solvent.

5. The hole transport layer precursor solution according to claim 4, characterized in that: The solvent is an alcohol solvent, a combination of an alcohol solvent and N,N-dimethylformamide, or a combination of an alcohol solvent and dimethyl sulfoxide; In the hole transport layer precursor solution, the mass of the compound of formula I is 0.1-5.0 mg per milliliter of solvent.

6. A hole transport layer, characterized in that The hole transport layer comprises the compound of formula I according to any one of claims 1 to 3; preferably, the hole transport layer has a thickness of 0.1 to 10 nm.

7. A method for preparing a hole transport layer, characterized in that: The method comprises coating the hole transport layer precursor solution according to claim 4 or 5, and then annealing to obtain the hole transport layer; preferably, the annealing method is heating annealing, the annealing temperature is 50-150°C, and the annealing time is 1-30 minutes, more preferably, the annealing temperature is 80-120°C, and the annealing time is 5-15 minutes.

8. A photovoltaic device, characterized in that: The photovoltaic device comprises a first hole transport layer, wherein the first hole transport layer is the hole transport layer according to claim 6; 9. The photovoltaic device according to claim 8, wherein The photovoltaic device sequentially comprises a conductive substrate, a first hole transport layer, a perovskite light absorption layer, an electron transport layer and an electrode.

10. The photovoltaic device according to claim 8, wherein The photovoltaic device is a perovskite solar cell; preferably, the perovskite solar cell is a single-junction perovskite cell, a crystalline silicon-perovskite tandem cell, a perovskite-perovskite tandem cell, a perovskite-copper indium gallium selenide tandem cell or a perovskite-gallium arsenide tandem cell.

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