Organic compound, hole transport layer, perovskite solar cell and preparation method

Abstract

The invention belongs to the photovoltaic field, and particularly relates to an organic compound, a hole transport layer, a perovskite solar cell and a preparation method. The organic compound disclosed by the invention is shown as a formula I; in the formula I, R1 and R2 are respectively and independently selected from aldehyde group, hydrogen, nitryl, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted ternary to twenty-membered heterocyclic group, substituted or unsubstituted C6-C20 aryl and substituted or unsubstituted quintuple to twenty-membered heteroaryl, and in the formula I, R1 and R2 are respectively and independently selected from aldehyde group, hydrogen, nitryl, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted ternary to twenty-membered heteroaryl; and R3 is a phosphate group. When the organic compound is used as a hole transport layer material, the efficiency and the stability of a perovskite solar cell can be effectively improved. # imgabs0 #

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and specifically relates to an organic compound, a hole transport layer, a perovskite solar cell and a preparation method thereof. Background Art

[0002] In recent years, organic and inorganic halide perovskites have attracted wide attention in the field of solar cells and light-emitting devices due to their excellent photoelectric conversion performance. Perovskite solar cells (PSCs) have gradually become a research hotspot in recent years due to their advantages such as simple preparation process and high photoelectric conversion efficiency (PCE).

[0003] However, if the industrialization of perovskite solar cells is to be realized, the stability of perovskite solar cells is a key technical issue that must be solved. In addition to the intrinsic stability of the perovskite composition, another key factor affecting the stability of PVCs is the choice of charge transport materials, especially the choice of organic hole transport layer (HTM) materials. Commonly used hole transport layer materials, such as Spiro-OMeTAD, show low hole mobility and require additional doping with lithium bis(trifluoromethane)sulfonyl imide (LiTFSI) / 4-tert-butylpyridine (tBP) to ensure effective hole extraction / transport; however, the hygroscopicity and diffusivity of these dopants will significantly affect the long-term stability of the device.

[0004] Therefore, it is urgent to develop an undoped hole transport material to improve the efficiency and stability of perovskite solar cells. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an organic compound represented by Formula I, which is used as a hole transport material to effectively improve the photoelectric conversion efficiency and stability of perovskite solar cells.

[0006] Specifically, the present invention provides an organic compound, which is as shown in Formula I;

[0007]

[0008] In formula I, R1 and R2 are each independently selected from aldehyde, hydrogen, nitro, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted three-membered to twenty-membered heterocyclyl, substituted or unsubstituted C6-C20 aryl and substituted or unsubstituted five-membered to twenty-membered heteroaryl; R3 is a phosphate group.

[0009] In one or more embodiments, in Formula I, R1 and R2 are each independently selected from aldehyde, hydrogen, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy and substituted or unsubstituted C6-C20 aryl; R3 is a phosphate group.

[0010] In one or more embodiments, the organic compound is selected from one or more of the following formulae:

[0011]

[0012]

[0013] The present invention provides a method for preparing the organic compound of the present invention, the method comprising the following steps:

[0014] (1) placing dibromophenothiazine, compound O, bis(dibenzylideneacetone)palladium, tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide in a first solvent for reaction to obtain compound A;

[0015] (2) placing 4-formylphenylboronic acid, compound A, potassium carbonate and tetrakis(triphenylphosphine)palladium in a second solvent for reaction to obtain compound B;

[0016] (3) placing compound B, diethyl cyanomethyl phosphate and piperidine in a third solvent for reaction to obtain compound C;

[0017] (4) reacting compound C and trimethylsilyl bromide in a fourth solvent to obtain an organic compound represented by formula I;

[0018] Among them, the structure of compound O is The structure of compound A is The structure of compound B is The structure of compound C is In compound O, compound A, compound B and compound C, R1 and R2 are as defined in any embodiment of the present invention.

[0019] In one or more embodiments, in step (1), the first solvent is toluene.

[0020] In one or more embodiments, in step (1), the molar ratio of dibromophenothiazine, compound O, bis(dibenzylideneacetone)palladium, tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide is 1:(1-1.2):(0.01-0.012):(0.01-0.012):(1-1.2).

[0021] In one or more embodiments, in step (1), the reaction temperature is 100-110°C.

[0022] In one or more embodiments, in step (1), the reaction is carried out in a protective atmosphere.

[0023] In one or more embodiments, in step (1), the reaction time is 10-12 hours.

[0024] In one or more embodiments, in step (2), the second solvent is toluene and / or tetrahydrofuran.

[0025] In one or more embodiments, in step (2), the molar ratio of formylphenylboronic acid, compound A, potassium carbonate and tetrakis(triphenylphosphine)palladium is (2-2.5):1:(2-2.5):(0.001-0.01).

[0026] In one or more embodiments, in step (2), tetrakis(triphenylphosphine)palladium is added in a protective atmosphere.

[0027] In one or more embodiments, in step (2), the reaction temperature is 80-90°C.

[0028] In one or more embodiments, in step (2), the reaction time is 16-24 hours.

[0029] In one or more embodiments, in step (3), the third solvent is toluene.

[0030] In one or more embodiments, in step (3), the molar ratio of compound B, diethyl cyanomethyl phosphate and piperidine is 1:(2-2.5):(0.5-0.6).

[0031] In one or more embodiments, in step (3), diethyl cyanomethylphosphonate and piperidine are added under a protective atmosphere.

[0032] In one or more embodiments, in step (3), the reaction temperature is 105-115°C.

[0033] In one or more embodiments, in step (3), the reaction time is 12-15 hours.

[0034] In one or more embodiments, in step (4), the fourth solvent is dichloromethane.

[0035] In one or more embodiments, in step (4), the molar ratio of compound C to trimethylsilyl bromide is 1:(15-25).

[0036] In one or more embodiments, in step (4), trimethylsilyl bromide is added dropwise to compound C and the fourth solvent.

[0037] In one or more embodiments, in step (4), the reaction temperature is 25-40°C.

[0038] In one or more embodiments, in step (4), the reaction time is 6-12 hours.

[0039] The present invention provides an organic compound according to any embodiment of the present invention.

[0040] In one or more embodiments, the hole transport layer has a thickness of 5-15 nm.

[0041] The present invention provides a method for preparing the hole transport layer of the present invention, the method comprising mixing an organic compound and a solvent to prepare a hole transport layer precursor solution; coating the hole transport layer precursor solution, and then annealing to prepare the hole transport layer.

[0042] In one or more embodiments, the concentration of the organic compound in the hole transport layer precursor solution is 0.25 to 2 mg / mL.

[0043] In one or more embodiments, the solvent is selected from one or more of isopropanol, ethanol, benzene, toluene, chlorobenzene, diethyl ether, and acetonitrile.

[0044] In one or more embodiments, the coating is performed by spin coating.

[0045] In one or more embodiments, the annealing temperature is 80-100°C.

[0046] In one or more embodiments, the annealing time is 5-10 min.

[0047] The present invention provides a perovskite solar cell comprising the hole transport layer of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Schematic diagram of the structure of perovskite solar cells prepared according to some embodiments of the present invention. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0050] 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.

[0051] 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 be disclosed herein.

[0052] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0053] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0054] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0055] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0056] Certain chemical groups defined herein are preceded by simplified symbols to indicate the total number of carbon atoms present in the group. For example, a C1-C6 alkyl group refers to an alkyl group as defined below having a total of 1 to 6 carbon atoms. The total number of carbon atoms in the simplified symbols does not include carbons that may be present in substituents of the group.

[0057] As used herein, the term "substituted", whether or not preceded by the term "optionally" (i.e., equivalent to substituted or unsubstituted), refers to the replacement of one or more hydrogens of a specified group or part by a "suitable substituent". Herein, the number of substituents may be one or more, i.e., 1, 2, 3, 4, 5 or 6 or more, depending on the nature of the substituted group and the substituent. For example, when the substituent of an ethyl group is a halogen, the group may be replaced by 1, 2, 3, 4 or 5 substituents, such as trifluoromethyl, pentafluoroethyl, etc., depending on the structure of the substituted group. In some embodiments, the number of the substituents is 1, 2 or 3. In some embodiments, the number of the substituents is 1 or 2. In some embodiments, the number of the substituents is 1. It will be understood that "substituted" or "substituted by..." includes implicit conditions, i.e., such substitutions are carried out according to the allowed valence of the substituted atom, and the substitution produces a stable or chemically feasible compound, such as a compound that will not spontaneously transform, such as by rearrangement, cyclization, elimination, etc. Unless otherwise indicated, an "optionally substituted" group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from the specified group, the substituent may be the same or different at each position. It will be understood by those skilled in the art that the substituent itself may be substituted if appropriate.

[0058] For the entire application, the above-mentioned “suitable substituents” should be understood to include, but are not limited to, the alkyl, alkenyl, alkynyl, halogen, haloalkyl, haloalkenyl, haloalkynyl, alkoxy, cyano, hydroxy, amino, monoalkylamino, dialkylamino, nitro, aryl, heteroaryl, cycloalkyl (e.g., cycloalkyl, cycloalkenyl, etc.), heterocyclyl, etc. described herein; these groups as substituents, including alkyl, alkenyl, alkynyl, alkyl in haloalkyl, alkenyl in haloalkenyl, alkynyl in haloalkynyl, alkoxy, alkyl in monoalkylamino, alkyl in dialkylamino, aryl, heteroaryl, cycloalkyl and heterocyclyl themselves are also optionally substituted, for example, they may also be optionally substituted by one or more groups selected from alkyl, halogen, haloalkyl, alkoxy, hydroxy, amino, monoalkylamino, dialkylamino, nitro, aryl, heteroaryl, cycloalkyl and heterocyclyl.

[0059] As used herein, "alkyl" refers to a straight or branched monovalent saturated hydrocarbon group having a specified number of carbon atoms, and specific alkyl groups are those having 1 to 20 carbon atoms ("C1-C20 alkyl"), usually containing 1-16 carbon atoms (C1-C16 alkyl), preferably containing 1-10 carbon atoms (C1-C10 alkyl), and more preferably containing 1-6 carbon atoms (C1-C6 alkyl). Examples of alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and the like. In some embodiments, the alkyl group suitable for the present invention can be a C1-C20 alkyl group, such as a C1 alkyl group, a C2 alkyl group, a C3 alkyl group, a C4 alkyl group, a C5 alkyl group, a C6 alkyl group, a C7 alkyl group, a C8 alkyl group, a C9 alkyl group, a C10 alkyl group, a C11 alkyl group, a C12 alkyl group, a C13 alkyl group, a C14 alkyl group, a C15 alkyl group, a C16 alkyl group, a C17 alkyl group, a C18 alkyl group, a C19 alkyl group, and a C20 alkyl group.

[0060] As used herein, as a group or part of other groups, the term "alkenyl" refers to a straight or branched hydrocarbon chain group consisting only of carbon atoms and hydrogen atoms, containing at least one double bond, connected to the rest of the molecule by a single bond. In some embodiments, the alkenyl contains 2 to 20 carbon atoms ("C2-C20 alkenyl"), preferably contains 2 to 10 carbon atoms ("C2-C10 alkenyl"), and more preferably contains 2 to 6 carbon atoms ("C2-C6 alkenyl"). Non-limiting examples of alkenyl include, but are not limited to, vinyl, propenyl, allyl, butenyl, but-1-enyl, but-2-enyl, pentenyl, penta-1-enyl, pentadienyl, penta-1,4-dienyl, etc. Unless otherwise specifically provided in this specification, alkenyl may be optionally substituted. In some embodiments, the alkenyl group suitable for the present invention may be a C2-C10 alkenyl group, such as a C2 alkenyl group, a C3 alkenyl group, a C4 alkenyl group, a C5 alkenyl group, a C6 alkenyl group, a C7 alkenyl group, a C8 alkenyl group, a C9 alkenyl group, a C10 alkenyl group.

[0061] As used herein, as a group or as part of other groups, the term "alkynyl" refers to a straight or branched hydrocarbon chain group consisting of only carbon atoms and hydrogen atoms with one or more carbon-carbon triple bonds (-C≡C-) connected to the rest of the molecule by a single bond. In some embodiments, the alkynyl contains 2-20 carbon atoms ("C2-C20 alkynyl"), preferably contains 2 to 10 carbon atoms ("C2-C10 alkynyl"), and more preferably contains 2 to 6 carbon atoms ("C2-C6 alkynyl"). Non-limiting examples of alkynyl include ethynyl, 1-propynyl, 1-methyl-2-propynyl, 2-propynyl, 1-butynyl and 2-butynyl, etc. Unless otherwise specifically provided in this specification, the alkynyl may be optionally substituted. In some embodiments, the alkynyl group suitable for the present invention can be a C2-C10 alkynyl group, such as a C2 alkynyl group, a C3 alkynyl group, a C4 alkynyl group, a C5 alkynyl group, a C6 alkynyl group, a C7 alkynyl group, a C8 alkynyl group, a C9 alkynyl group, a C10 alkynyl group.

[0062] As used herein, "cycloalkyl" or "carbocyclyl" refers to a saturated cyclic hydrocarbon with 3 to 10 ring carbon atoms (C3, C4, C5, C6, C7, C8, C9, C10), which contains one ring such as cyclohexyl or multiple rings such as adamantyl. The cycloalkyl containing more than one ring can be fused, spirocyclic or bridged or a combination thereof. Preferred cycloalkyls are saturated cyclic hydrocarbons with 3 to 8 ring carbon atoms ("C3-C8 cycloalkyl"). In some embodiments, the cycloalkyl group has 4 to 6 ring carbon atoms ("C4-C6 cycloalkyl"). Examples of cycloalkyls include adamantyl, decahydronaphthyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and cycloheptyl, etc.

[0063] As used herein, the term "heterocyclyl" or "heterocycle", as a group or part of another group, means a stable saturated or partially unsaturated non-aromatic cyclic group or moiety consisting of carbon atoms (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 carbon atoms) and heteroatoms (e.g., 1 to 6 heteroatoms, more preferably 1, 2 or 3 heteroatoms) selected from nitrogen, phosphorus, oxygen and sulfur (preferably nitrogen, oxygen or sulfur). In some embodiments, the heterocyclyl group may contain 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 ring-forming atoms, e.g., 3 to 20 ring-forming atoms, 3 to 19 ring-forming atoms, 3 to 18 ring-forming atoms, 3 to 17 ring-forming atoms, 3 to 16 ring-forming atoms, 3 to 15 ring-forming atoms, 4 to 12 ring-forming atoms, 4 to 10 ring-forming atoms, 4 to 9 ring-forming atoms, 4 to 8 ring-forming atoms, 4 to 7 ring-forming atoms, 4 to 6 ring-forming atoms, 4 to 5 ring-forming atoms. Unless otherwise specifically indicated in this specification, the heterocyclic group can be a monocyclic, bicyclic, tricyclic or more ring system, which may include a fused / annular system (i.e., an annular heterocyclic group, such as a 4-9-member annular heterocyclic group), a bridged ring system (i.e., a bridged heterocyclic group, such as a 6-12-membered bridged heterocyclic group) or a spirocyclic system (i.e., a spiro heterocyclic group, such as a 6-12-membered spiro heterocyclic group). An annular heterocyclic group refers to a ring system of a heterocyclic group consisting of multiple (e.g., two, three or more) rings, wherein at least two rings are combined with each other by sharing two adjacent atoms (i.e., the at least two rings share a covalent bond, so that the bridgehead atoms are directly connected), preferably a bicyclic annular heterocyclic group. A bridged heterocyclic group refers to a ring system of a heterocyclic group consisting of multiple (e.g., two, three or more) rings, wherein at least two rings are combined with each other by sharing three or more atoms (the at least two rings are separated by two bridgehead atoms through a bridge containing at least one atom). Spiro heterocyclic group refers to a ring system of a heterocyclic group consisting of multiple (e.g., two, three or more) rings, wherein at least two rings are heterocyclic groups that are combined with a common carbon atom. The nitrogen, carbon or sulfur atom in the heterocyclic group may be optionally oxidized, and the nitrogen atom may be optionally quaternized. The heterocyclic group may be connected to the rest of the molecule via a carbon atom or a heteroatom and by a single bond. In some cases, the heterocyclic group may be carbon-connected, nitrogen-connected or sulfur-connected. In some embodiments, the heterocyclic group is carbon-connected. In some embodiments, the heterocyclic group is nitrogen-connected. In some embodiments, the heterocyclic group is sulfur-connected. Unless otherwise specifically provided in this specification, the heterocyclic group may be optionally substituted.

[0064] Heterocyclyl also includes groups in which the heterocyclyl group is fused to a saturated, partially unsaturated or fully unsaturated (i.e., aromatic) cycloalkyl, aryl, heterocyclyl or heteroaryl group. In heterocyclyl groups containing fused rings, one or more rings may be aryl or heteroaryl as defined below. Examples of fused heterocyclic groups include, but are not limited to, phenyl-fused heterocyclic groups or pyridyl-fused heterocyclic groups, as well as quinolyl, isoquinolyl, quinoxalinyl, quinolizinyl, quinazolinyl, azaindolizinyl, pteridinyl, chromenyl, isochromenyl, indolyl, isoindolyl, indolizinyl, indazolyl, purinyl, benzofuranyl, isobenzofuranyl, benzimidazolyl, benzothiophenyl, benzothiazolyl, carbazolyl, phenazinyl, phenothiazinyl, phenanthridinyl, imidazo[1,2-a]pyridinyl, [1,2,4]triazolo[4,3-a]pyridinyl, [1,2,3]triazolo[4,3-a]pyridinyl-fused heterocyclic groups, and the like.

[0065] In some embodiments, the heterocyclyl group is a stable 4- to 12-membered, 5- to 12-membered, 6- to 10-membered, 4- to 10-membered, or 4- to 9-membered non-aromatic monocyclic, bicyclic, tricyclic or more cyclic group (including cyclic, bridged or spirocyclic groups) containing 1 to 3 heteroatoms selected from nitrogen, oxygen and sulfur, for example, a stable 5- to 10-membered (e.g., 4- to 9-membered) non-aromatic monocyclic, bicyclic, tricyclic or more cyclic group (including cyclic, bridged or spirocyclic groups) containing 1 to 3 heteroatoms selected from nitrogen, oxygen and sulfur. Examples of heterocyclic groups include, but are not limited to, pyrrolidinyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, thiomorpholinyl, 2,7-diaza-spiro[3.5]nonan-7-yl, 2-oxa-6-aza-spiro[3.3]heptane-6-yl, 2-oxa-6-aza-spiro[3.4]octan-7-yl, 8-oxa-2-aza-spiro[4.5]decane-6-yl, 2,5-diaza-bicyclo[2.2.1]heptane-2-yl, azetidinyl, oxetanyl, thietanyl, thia Cyclopentanyl, pyranyl, tetrahydropyranyl, thiopyranyl, tetrahydrofuranyl, oxazinyl, dioxolane, tetrahydroisoquinolyl, decahydroisoquinolyl, imidazolinyl, imidazolidinyl, quinolizinyl, thiazolidinyl, isothiazolidinyl, isoxazolidinyl, dihydroindolyl, octahydroindolyl, octahydroisoindolyl, pyrazolidinyl, phthalimido, dioxothiomorpholinyl, dioxothiolane, dioxothietane, thiacyclohexane, dioxothiocyclohexane, thiomorpholinyl, 1,4-oxathiacyclohexane, and the like.

[0066] As used herein, "alkoxy" refers to alkyl-O-, and the definition of alkyl is as described above. Preferred alkoxy is C1-C20 alkoxy, such as C1-C16 alkoxy, C1-C10 alkoxy, C1-C8 alkoxy, C1-C6 alkoxy, C1-C4 alkoxy, which includes, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexyloxy, 1,2-dimethylbutoxy, etc.

[0067] As used herein, "alkylthio" refers to an alkyl-S- group, wherein alkyl is as defined above.

[0068] As used herein, "halo" or "halogen" refers to an element of Group 17 with an atomic number of 9 to 85. "Halogen" or "halogen atom" refers to F, Cl, Br, and I. "Halogenated" means substituted with an atom selected from F, Cl, Br, and I.

[0069] As used herein, "aldehyde" refers to -CHO.

[0070] As used herein, "amino" refers to -NH2.

[0071] As used herein, "carboxyl" refers to -COOH.

[0072] As used herein, "nitro" refers to -NO2.

[0073] As used herein, "hydroxy" refers to -OH.

[0074] As used herein, "cyano" refers to -CN.

[0075] As used herein, "phosphate group" refers to -PO(OH)2.

[0076] As used herein, "aryl" refers to an unsaturated aromatic carbocyclic monovalent group having a single ring (e.g., phenyl) or multiple fused rings (e.g., naphthyl or anthracenyl), wherein the fused rings may or may not be aromatic. In one variation, the aryl group comprises 6 to 14 ring carbon atoms ("C6-C14 aryl"), preferably C6-C10 aryl. The aryl group having more than one ring and at least one of which is a non-aromatic ring may be attached to the parent structure at an aromatic ring position or at a non-aromatic ring position. Examples of aryl groups include phenyl, fluorenyl, naphthyl, phenanthrenyl, anthracenyl, indenyl, azulenyl, biphenyl, biphenylene and fluorenyl.

[0077] As used herein, "heteroaryl" refers to a monovalent group containing 5-14, preferably 5-10 ring atoms, and having 6, 10 or 14 π electrons shared in the ring system. The ring atoms contained in the heteroaryl group are carbon atoms and 1, 2, 3 or 4 heteroatoms selected from N, O, S and Se. In the present invention, the preferred heteroaryl group is a heteroaryl group containing N, S or O atoms, and more preferably a heteroaryl group containing N or S atoms. Examples of heteroaryl groups include: carbazolyl, triazolyl, thienyl, furanyl, pyranyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, benzimidazolyl, dibenzothienyl, dibenzopyridinyl and pyrazolopyrimidinyl, etc.

[0078] As used herein, the number of "members" before "heterocyclyl" and "heteroaryl" refers to the number of ring atoms. For example, a three-membered to twenty-membered heterocyclyl group means that the number of ring atoms of the heterocyclyl group is 3 to 20.

[0079] The present invention provides an organic compound shown in Formula I; in Formula I, R1 and R2 are each independently selected from an aldehyde group, hydrogen, nitro, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted three-membered to twenty-membered heterocyclic group, substituted or unsubstituted C6-C20 aryl and substituted or unsubstituted five-membered to twenty-membered heteroaryl; R3 is a phosphate group; preferably, in Formula I, R1 and R2 are each independently selected from an aldehyde group, hydrogen, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy and substituted or unsubstituted C6-C20 aryl; R3 is a phosphate group. In the present invention, the organic compound shown in Formula I introduces a variety of substituent groups into the end groups of the triphenylamine structural unit, which can regulate the interface energy level, increase the solubility of the organic compound shown in Formula I in the organic solvent, and then form a uniform hole transport layer, promote charge transfer, and thus achieve the improvement of the efficiency of the perovskite solar cell; the sulfur atoms and nitrogen atoms contained in the organic compound shown in Formula I can passivate the bottom defects of the perovskite, and then improve the stability of the perovskite solar cell; the present invention uses a diphosphate group molecule, so that the hole transport layer and the substrate are in better and more stable contact, thereby further improving the stability of the perovskite solar cell.

[0080]

[0081] In some embodiments, the organic compound of formula I is selected from one or more of the following formulae:

[0082]

[0083]

[0084] The present invention provides a method for preparing an organic compound represented by formula I, the method comprising the following steps:

[0085] (1) placing dibromophenothiazine, compound O, bis(dibenzylideneacetone)palladium, tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide in a first solvent for reaction to obtain compound A;

[0086]

[0087] (2) placing 4-formylphenylboronic acid, compound A, potassium carbonate and tetrakis(triphenylphosphine)palladium in a second solvent for reaction to obtain compound B;

[0088]

[0089] (3) placing compound B, diethyl cyanomethyl phosphate and piperidine in a third solvent for reaction to obtain compound C;

[0090]

[0091] (4) reacting compound C and trimethylsilyl bromide in a fourth solvent to obtain an organic compound represented by formula I;

[0092]

[0093] Among them, the structure of compound O is The structure of compound A is The structure of compound B is The structure of compound C is In formula I, R1 and R2 are each independently selected from aldehyde, hydrogen, nitro, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted three-membered to twenty-membered heterocyclyl, substituted or unsubstituted C6-C20 aryl and substituted or unsubstituted five-membered to twenty-membered heteroaryl.

[0094] In step (1), the first solvent may be toluene (tol). In step (1), the molar ratio of dibromophenothiazine, compound O, bis(dibenzylideneacetone) palladium (Pd(dba)2), tri-tert-butylphosphine tetrafluoroborate (HP(t-Bu)3BF4) and sodium tert-butoxide (t-BuONa) may be 1:(1-1.2):(0.01-0.012):(0.01-0.012):(1-1.2). In step (1), the reaction temperature may be 100-110°C, for example, 100°C, 102°C, 104°C, 106°C, 108°C, 110°C. In step (1), the reaction is carried out in a protective atmosphere, and the protective gas may be argon (Ar). In step (1), the reaction time may be 10-12 h, for example 10 h, 10.5 h, 11 h, 11.5 h, 12 h.

[0095] In step (2), the second solvent may be toluene and / or tetrahydrofuran (THF). In step (2), the molar ratio of formylphenylboronic acid, compound A, potassium carbonate and tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) may be (2-2.5):1:(2-2.5):(0.001-0.01). In step (2), tetrakis(triphenylphosphine)palladium may be added in a protective atmosphere. In step (2), the reaction temperature may be 80-90°C, for example, 80°C, 82°C, 84°C, 86°C, 88°C, 90°C. In step (2), the reaction time may be 16-24h, for example, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h.

[0096] In step (3), the third solvent may be toluene. In step (3), the molar ratio of compound B, diethyl cyanomethyl phosphate and piperidine may be 1:(2-2.5):(0.5-0.6). In step (3), diethyl cyanomethyl phosphate and piperidine may be added in a protective atmosphere. In step (3), the reaction temperature may be 105-115°C, for example, 105°C, 107°C, 109°C, 111°C, 113°C, 115°C. In step (3), the reaction time may be 12-15h, for example, 12h, 12.5h, 13h, 13.5h, 14h, 14.5h, 15h.

[0097] In step (4), the fourth solvent may be dichloromethane (DCM). In step (4), the molar ratio of compound C and trimethylsilyl bromide (MeSiBr) may be 1: (15-25), such as 1: 15, 1: 16, 1: 17, 1: 18, 1: 19, 1: 20, 1: 21, 1: 22, 1: 23, 1: 24, 1: 25. In step (4), trimethylsilyl bromide may be added dropwise to compound C and the fourth solvent. In step (4), the reaction temperature may be 25-40°C, such as 25°C, 30°C, 35°C, 40°C. In step (4), the reaction time may be 6-12h, such as 6h, 7h, 8h, 9h, 10h, 11h, 12h.

[0098] In the present invention, the protective atmosphere can be a protective gas commonly used in the art, such as nitrogen and argon.

[0099] The present invention provides a hole transport layer comprising the organic compound of the present invention. In the present invention, the thickness of the hole transport layer can be 5-15 nm, for example, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm.

[0100] The present invention provides a method for preparing the hole transport layer of the present invention, the method comprising mixing an organic compound and a solvent to prepare a hole transport layer precursor solution; coating the hole transport layer precursor solution, and then annealing to prepare the hole transport layer.

[0101] In the hole transport layer precursor solution of the present invention, the concentration of the organic compound can be 0.25-2 mg / mL, preferably 0.5-1 mg / mL, for example 0.5 mg / mL, 0.75 mg / mL, 1 mg / mL. In the hole transport layer precursor solution of the present invention, the solvent can be one or more selected from isopropanol, ethanol, benzene, toluene, chlorobenzene, ether and acetonitrile. In the hole transport layer precursor solution of the present invention, the coating method can be spin coating. In the process of preparing the hole transport layer of the present invention, the annealing temperature can be 80-100°C, for example 80°C, 85°C, 90°C, 95°C, 100°C. In the process of preparing the hole transport layer of the present invention, the annealing time can be 5-10min, for example 5min, 6min, 7min, 8min, 9min, 10min.

[0102] 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. In the present invention, the perovskite solar cell may be a formal single-junction perovskite solar cell, an inverted single-junction perovskite solar cell, a formal tandem perovskite solar cell or an inverted tandem perovskite solar cell. In the present invention, the inverted single-junction perovskite solar cell may include a transparent conductive substrate, a hole transport layer, a perovskite layer, an electron transport layer and an electrode layer in sequence. In some embodiments, the inverted single-junction perovskite solar cell further includes an interface barrier layer, which is located between the electron transport layer and the electrode layer. In the present invention, the inverted tandem perovskite solar cell may include a bottom electrode, a bottom cell, a tunneling layer, an inverted perovskite top cell and a top electrode in sequence, and the inverted top cell may include a hole transport layer, a perovskite layer and an electron transport layer in sequence.

[0103] In the present invention, the conductive substrate may include a substrate and a transparent conductive layer, the substrate may be made of glass, and the transparent conductive layer may be made of indium tin oxide (ITO). In the present invention, the material of the perovskite layer may be a perovskite structure material, and the chemical formula of the perovskite structure material is ABX3, wherein A may be selected from cesium ions (Cs + ), rubidium ions (Rb + ), methylamine ion (CH3NH3 + , M.A. + ) and formamidinium ion (CH(NH2)2 + , F.A. + ), B is selected from lead ions (Pb 2+ ) and / or tin ions (Sn 2+ ), X can be a halogen ion, preferably selected from iodide ion (I - ), bromide ion (Br - ) and chloride ions (Cl - ) or more. In the present invention, the material of the electron transport layer may be one or more selected from [6,6]-phenyl-C61-butyric acid methyl ester, C60 and tin oxide. In the present invention, the material of the hole blocking layer may be 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) or zirconium acetylacetonate. In the present invention, the material of the electrode layer may be silver, copper or carbon.

[0104] The method for preparing a transverse single-junction perovskite solar cell of the present invention comprises:

[0105] (1) depositing a hole transport layer on the surface of a conductive substrate;

[0106] (2) depositing a perovskite layer on the surface of the hole transport layer;

[0107] (3) depositing an electron transport layer on the surface of the perovskite layer;

[0108] (4) Depositing an electrode layer on the surface of the electron transport layer to obtain an inverted single-junction perovskite solar cell.

[0109] The method for preparing an inverted stacked perovskite solar cell of the present invention comprises:

[0110] (1) depositing a bottom electrode and a tunneling layer on both sides of the bottom cell;

[0111] (2) depositing a hole transport layer on the surface of the tunneling layer;

[0112] (3) depositing a perovskite layer on the surface of the hole transport layer;

[0113] (4) depositing an electron transport layer on the surface of the perovskite layer;

[0114] (5) A top electrode is deposited on the surface of the electron transport layer to obtain an inverted stacked perovskite solar cell.

[0115] Compared with the prior art, the present invention has the following beneficial technical effects: (1) The present invention can introduce a variety of substituent groups into the end groups of the triphenylamine structural unit, regulate the interface energy level, increase the solubility of the material in the organic solvent, form a uniform hole transport layer, and promote charge transfer; (2) The sulfur atoms and nitrogen atoms contained in the molecule can passivate the bottom defects of the perovskite; (3) The present invention uses a diphosphate group molecule to make the contact between the hole transport layer and the substrate more stable, thereby improving the stability of the perovskite solar cell; (4) The present invention uses cyanophosphate as an electron-withdrawing group, which can effectively realize charge transfer between molecules and improve carrier mobility, thereby achieving high photoelectric conversion efficiency.

[0116] The present invention will be described below in the form 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 raw material compounds in the examples can all be purchased through commercial routes.

[0117] Example 1

[0118] In this embodiment, the organic compound represented by formula I is prepared, and the specific steps are as follows:

[0119] (1) 1.65 mmol of monobromotriphenylamine (compound O), 1.5 mmol of dibromophenothiazine, 0.017 mmol of bis(dibenzylideneacetone)palladium, 0.019 mmol of tri-tert-butylphosphine tetrafluoroborate and 1.8 mmol of sodium tert-butoxide were dissolved in 5 mL of toluene and refluxed at 105° C. for 10 h under an argon atmosphere. After the reaction was completed, 8 mL of dichloromethane (DCM) was added to the mixture, evaporated to dryness, and purified by chromatography to obtain compound A;

[0120] (2) 14 mmol 4-formylphenylboronic acid, 6 mmol compound A and 15 mmol potassium carbonate were dissolved in a mixed solvent of 80 mL toluene and 40 mL tetrahydrofuran, with a volume ratio of toluene to tetrahydrofuran being 2:1. 0.043 tetrakis(triphenylphosphine)palladium was added under N2 protection conditions, and the mixture was reacted at 80° C. for 18 h. After the reaction was completed, the mixture was extracted with dichloromethane three times, and the organic layer was dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure and then purified by silica gel column chromatography. The obtained product was recrystallized from ethanol to obtain compound B.

[0121] (3) 10 mmol of compound B was dissolved in toluene, and under nitrogen protection, 22 mmol of diethyl cyanomethyl phosphate and 5 mmol of piperidine were added, and the temperature was raised to 110° C. and stirred for reaction for 12 hours; after the reaction was completed, the organic solvent was removed by rotary evaporation until it was dry, and then dichloromethane was added to dissolve it again, and extraction was performed in sequence. After drying and concentration, it was further purified using a chromatography column to obtain compound C;

[0122] (4) Dissolve 1 mmol of compound C in 20 mL of dichloromethane, slowly add 2.5 mL of trimethylsilyl bromide with a syringe, and stir at 25°C for 8 h. After the reaction is complete, add dichloromethane and deionized water. Extract with dichloromethane three times, collect the organic phase in a conical flask, dry the combined organic layer over anhydrous Na2SO4, and spin dry the organic phase under reduced pressure to obtain the structure of of organic compounds.

[0123] The organic compound obtained in Example 1 was subjected to nuclear magnetic resonance detection, and the test results were: 1 H NMR(500MHz,Chloroform-d)δ9.07(s,4H),7.89(s,2H),7.78–7.72(m,4H),7.58(dd,J=7.1,2.1Hz,2H),7.52–7.48(m,4H),7.46(d,J=7.1Hz,1 H),7.40(d,J=7.1Hz,1H),7.30(d,J=2.2Hz,2H),7.22–7.17(m,2H),7.13–7.08(m,2H),7.06(d,J=8.1Hz,4H),7.04–7.00(m,4H),2.35(s,6H).

[0124] Example 2

[0125] The other conditions of this embodiment are the same as those of embodiment 1, except that the monobromotriphenylamine in step (1) of embodiment 1 is replaced with 4-bromo-4',4"-dimethyltriphenylamine to obtain a product having the structure of organic compounds.

[0126] The organic compound obtained in Example 2 was subjected to nuclear magnetic resonance detection, and the test results were: 1 H NMR(500MHz,Chloroform-d)δ9.07(s,4H),7.89(s,2H),7.79–7.74(m,4H),7.58(dd,J=7.2,2.1Hz,2H),7.52–7.48(m,4H),7.46(d,J=7 .1Hz,1H),7.40(d,J=7.1Hz,1H),7.30(d,J=2.2Hz,2H),7.19(dd,J=7.6,1.5Hz,2H),7.13–7.09(m,2H),7.08–7.00(m,8H),2.35(s,6H).

[0127] Example 3

[0128] The other conditions of this embodiment are the same as those of embodiment 1, except that the monobromotriphenylamine in step (1) of embodiment 1 is replaced with 4-bromo-4',4'-dimethoxytriphenylamine to obtain a product having the structure of organic compounds.

[0129] The organic compound obtained in Example 3 was subjected to nuclear magnetic resonance detection, and the test results were: 1 H NMR(500MHz,Chloroform-d)δ9.07(s,4H),7.89(s,2H),7.78–7.75(m,4H),7.58(dd,J=7.1,2.1Hz,2H),7.52–7.48(m,4H),7. 46(d,J=7.1Hz,1H),7.40(d,J=7.1Hz,1H),7.29(s,2H),7.21–7.17(m,2H),7.14–7.08(m,6H),6.94–6.90(m,4H),3.79(s,6H).

[0130] Example 4

[0131] The other conditions of this embodiment are the same as those of embodiment 1, except that the monobromotriphenylamine in step (1) of embodiment 1 is replaced with 4,4'-dibromo-4"-phenyltriphenylamine to obtain a product having the structure of organic compounds.

[0132] The organic compound obtained in Example 4 was subjected to nuclear magnetic resonance detection, and the test results were: 1 H NMR(500MHz,Chloroform-d)δ9.07(s,4H),7.89(s,2H),7.78–7.72(m,4H),7.61–7.55(m,6H),7.51–7.47(m,6H),7.45(dd,J=1 0.0,7.5Hz,3H),7.40(d,J=7.2Hz,2H),7.30(d,J=2.2Hz,2H),7.22–7.18(m,4H),7.15(d,J=8.4Hz,2H),7.11(d,J=7.6Hz,2H).

[0133] Example 5

[0134] The other conditions of this embodiment are the same as those of embodiment 1, except that the monobromotriphenylamine in step (1) of embodiment 1 is replaced by The obtained structure is of organic compounds.

[0135] The organic compound obtained in Example 5 was subjected to nuclear magnetic resonance detection, and the test results were: 1 H NMR(500MHz,Chloroform-d)δ9.07(s,4H),7.89(s,2H),7.81–7.70(m,4H),7.58 (dd,J=7.1,2.1Hz,2H),7.52–7.48(m,4H),7.46(d,J=7.1Hz,1H),7.40(d,J=7.1 Hz,1H),7.30(d,J=2.2Hz,2H),7.19(d,J=7.4Hz,2H),7.11(d,J=7.6Hz,2H),7.0 7–7.03(m,4H),6.70–6.65(m,4H),3.99(d,J=5.8Hz,2H),3.94(d,J=5.8Hz,2H).

[0136] Example 6

[0137] The other conditions of this example are the same as those of Example 1, except that the monobromotriphenylamine in step (1) of Example 1 is replaced with 4,4'-((4-bromophenyl)azadiyl)benzaldehyde to obtain a product having the structure of organic compounds.

[0138] The organic compound obtained in Example 6 was subjected to nuclear magnetic resonance detection, and the results were: 1H NMR(500MHz,Chloroform-d)δ9.93(s,2H),9.07(s,4H),7.89(s,2H),7.81(d,J=7.6Hz,4H),7.78–7.75(m,4H),7.58(dd,J=7.1,2.1Hz,2H),7. 53–7.48(m,4H),7.46(d,J=7.1Hz,1H),7.40(d,J=7.1Hz,1H),7.35–7. 30(m,4H),7.30(d,J=2.2Hz,2H),7.22–7.17(m,2H),7.13–7.07(m,2H).

[0139] Example 7

[0140] The other conditions of this embodiment are the same as those of embodiment 1, except that the monobromotriphenylamine in step (1) of embodiment 1 is replaced by The obtained structure is of organic compounds.

[0141] The organic compound obtained in Example 7 was subjected to nuclear magnetic resonance detection, and the result was: 1 H NMR(500MHz,Chloroform-d)δ9.07(s,4H),7.89(s,2H),7.78–7.74(m,4H),7.60(d, J=7.4Hz,2H),7.58(dd,J=7.1,2.1Hz,2H),7.50(dt,J=7.1,1.6Hz,5H),7.48(d,J=1. 3Hz,1H),7.46(d,J=7.1Hz,1H),7.40(d,J=7.1Hz,1H),7.30(d,J=2.1Hz,2H),7.27( d,J=7.4Hz,2H),7.19(d,J=7.4Hz,2H),7.15(d,J=8.4Hz,2H),7.11(d,J=7.6Hz,2H).

[0142] Example 8

[0143] Preparation of this example Figure 1 The perovskite solar cell shown in the figure has the following specific steps:

[0144] 1. The ITO conductive glass was ultrasonically cleaned with deionized water, acetone and isopropanol for 15 minutes respectively, and finally dried in a drying oven at 75°C for standby use; the dried ITO glass substrate was placed in an ultraviolet ozone machine for 5 minutes to remove organic impurities on its surface to obtain a conductive substrate;

[0145] 2. Preparation of a hole transport layer: Dissolve 0.5 mg of compound I-1 in 1 mL of chlorobenzene and stir at 25°C until completely dissolved to obtain a hole transport layer precursor solution; spin coat the hole transport layer precursor solution on a conductive substrate at a speed of 2000 r / min for 30 seconds, and then heat anneal at 100°C for 10 minutes to obtain a hole transport layer with a thickness of 8 nm;

[0146] 3. Preparation of perovskite layer: 0.4610g PbI2 and 0.1589g CH3NH3I were weighed and dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) (the volume ratio of DMF and DMSO was 4:1) to prepare a 1.2mol / L perovskite precursor solution, and the perovskite precursor solution was spin-coated on the hole transport layer at a speed of 5000r / min for 30s, and 300μL ethyl acetate anti-solvent was added at the 6th second, and then heated on a heating table at 100°C for 15min to obtain a perovskite layer with a thickness of 800nm;

[0147] 4. Preparation of electron transport layer: 20 mg of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was dissolved in 1 mL of chlorobenzene and stirred at 25°C to obtain a [6,6]-phenyl-C61-butyric acid methyl ester solution; 30 μL of the [6,6]-phenyl-C61-butyric acid methyl ester solution was spin-coated on a conductive substrate having a perovskite layer at 3000 rpm for 60 seconds to obtain an electron transport layer with a thickness of 30 nm;

[0148] 5. Preparation of hole blocking layer: 0.5 mg of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) was dissolved in 1 mL of isopropanol and stirred at 25°C to prepare a hole blocking layer solution; 40 μL of the hole blocking layer solution was added dropwise to the top of the electron transport layer and spin coated at 5000 rpm for 35 seconds to form a hole blocking layer with a thickness of 6 nm;

[0149] 6. Preparation of electrode layer: Transfer the conductive substrate with hole blocking layer, electron transport layer, perovskite layer and hole transport layer to the vacuum coating instrument and wait until the vacuum degree reaches 3×10 -4 Silver was evaporated at 400 Pa to form an electrode layer with a thickness of 100 nm, and a perovskite solar cell was obtained at the same time.

[0150] Example 9

[0151] The other conditions of this example are the same as those of Example 1, except that the organic compound is replaced by Compound I-2 in this example.

[0152] Example 10

[0153] The other conditions of this example are the same as those of Example 1, except that the organic compound is replaced by compound I-3 in this example.

[0154] Embodiment 11

[0155] The other conditions of this example are the same as those of Example 1, except that the organic compound is replaced by compound I-4 in this example.

[0156] Example 12

[0157] The other conditions of this example are the same as those of Example 1, except that the organic compound is replaced with compound I-5 in this example.

[0158] Embodiment 13

[0159] The other conditions of this example are the same as those of Example 1, except that the organic compound is replaced with compound I-6 in this example.

[0160] Embodiment 14

[0161] The other conditions of this example are the same as those of Example 1, except that the organic compound is replaced with compound I-7 in this example.

[0162] Embodiment 15

[0163] The other conditions of this embodiment are the same as those of Embodiment 1, except that the amount of the organic compound is changed to 2 mg in this embodiment, and the thickness of the prepared hole transport layer is 15 nm.

[0164] Example 16

[0165] The other conditions of this embodiment are the same as those of Embodiment 1, except that the amount of the organic compound is changed to 0.25 mg in this embodiment, and the thickness of the prepared hole transport layer is 5 nm.

[0166] Comparative Example 1

[0167] The other conditions of this comparative example are the same as those of Example 1, except that the preparation method of the hole transport layer in this comparative example is as follows: 70 mg of 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) is dissolved in 1 mL of chlorobenzene solution, and 29.0 μL of tetraphenylbenzidine (TPB) and 17.5 μL of Li-TFSI solution (the solvent is acetonitrile, and the Li-TFSI concentration is 520 mg / mL) are added dropwise to the solution to obtain a hole transport layer precursor solution with a Spiro-OMeTAD concentration of 70 mg / mL, which is then spin-coated on a conductive substrate at a speed of 2000 r / min for 30 s to obtain a hole transport layer with a thickness of 7 nm.

[0168] Test Case

[0169] Device performance test of perovskite solar cells: Under the AM 1.5G standard solar spectrum, a solar simulator was used to set the voltage range to -0.1-1.2V, and the current output of the perovskite solar cells prepared in Examples 8-16 and Comparative Example 1 at different voltages was tested, and the corresponding current-voltage (IV) characteristic curves were plotted, where the cell surface area was 0.049087cm 2 , the incident light power (Pin) is 100mW / cm 2 The open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 8-16 and Comparative Example 1 were obtained according to the characteristic curves.

[0170] (1) Open circuit voltage (Voc): The voltage value corresponding to when the current is equal to zero.

[0171] (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.

[0172] (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.

[0173] (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%.

[0174] The test results of the open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 8-16 and Comparative Example 1 are shown in Table 1.

[0175] Table 1: Open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of perovskite solar cells prepared in Examples 8-16 and Comparative Example 1

[0176]

[0177]

Claims

1. An organic compound, characterized in that The organic compound is as shown in formula I; In formula I, R1 and R2 are each independently selected from aldehyde, hydrogen, nitro, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted three-membered to twenty-membered heterocyclyl, substituted or unsubstituted C6-C20 aryl and substituted or unsubstituted five-membered to twenty-membered heteroaryl; R3 is a phosphate group.

2. The organic compound according to claim 1, characterized in that In formula I, R1 and R2 are each independently selected from aldehyde, hydrogen, halogen, amino, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C1-C20 alkoxy and substituted or unsubstituted C6-C20 aryl; R3 is a phosphate group.

3. The organic compound according to claim 1, characterized in that The organic compound is selected from one or more of the following formulae:

4. A method for preparing the organic compound according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (1) placing dibromophenothiazine, compound O, bis(dibenzylideneacetone)palladium, tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide in a first solvent for reaction to obtain compound A; (2) placing 4-formylphenylboronic acid, compound A, potassium carbonate and tetrakis(triphenylphosphine)palladium in a second solvent for reaction to obtain compound B; (3) placing compound B, diethyl cyanomethyl phosphate and piperidine in a third solvent for reaction to obtain compound C; (4) reacting compound C and trimethylsilyl bromide in a fourth solvent to obtain an organic compound represented by formula I; Among them, the structure of compound O is The structure of compound A is The structure of compound B is The structure of compound C is In compound O, compound A, compound B and compound C, R1 and R2 are as defined in any one of claims 1 to 3.

5. The method according to claim 4, characterized in that The method has one or more of the following features: In step (1), the first solvent is toluene; In step (1), the molar ratio of dibromophenothiazine, compound O, bis(dibenzylideneacetone)palladium, tri-tert-butylphosphine tetrafluoroborate and sodium tert-butoxide is 1:(1-1.2):(0.01-0.012):(0.01-0.012):(1-1.2); In step (1), the reaction temperature is 100-110°C; In step (1), the reaction is carried out in a protective atmosphere; In step (1), the reaction time is 10-12h; In step (2), the second solvent is toluene and / or tetrahydrofuran; In step (2), the molar ratio of formylphenylboronic acid, compound A, potassium carbonate and tetrakis(triphenylphosphine)palladium is (2-2.5):1:(2-2.5):(0.001-0.01); In step (2), tetrakis(triphenylphosphine)palladium is added in a protective atmosphere; In step (2), the reaction temperature is 80-90°C; In step (2), the reaction time is 16-24h; In step (3), the third solvent is toluene; In step (3), the molar ratio of compound B, diethyl cyanomethyl phosphate and piperidine is 1:(2-2.5):(0.5-0.6); In step (3), diethyl cyanomethyl phosphate and piperidine are added in a protective atmosphere; In step (3), the reaction temperature is 105-115°C; In step (3), the reaction time is 12-15h; In step (4), the fourth solvent is dichloromethane; In step (4), the molar ratio of compound C to trimethylsilyl bromide is 1:(15-25); In step (4), trimethylsilyl bromide is added dropwise to compound C and the fourth solvent; In step (4), the reaction temperature is 25-40°C; In step (4), the reaction time is 6-12 hours.

6. A hole transport layer, characterized in that: The hole transport layer comprises the organic compound according to any one of claims 1 to 3.

7. The hole transport layer according to claim 6, characterized in that The thickness of the hole transport layer is 5-15 nm.

8. A method for preparing the hole transport layer according to claim 6 or 7, characterized in that: The method comprises the steps of mixing an organic compound and a solvent to prepare a hole transport layer precursor solution; coating the hole transport layer precursor solution, and then annealing to prepare a hole transport layer.

9. The method according to claim 8, characterized in that The method has one or more of the following features: In the hole transport layer precursor solution, the concentration of the organic compound is 0.25 to 2 mg / mL; The solvent is selected from one or more of isopropanol, ethanol, benzene, toluene, chlorobenzene, ether and acetonitrile; The coating method is spin coating; Annealing temperature is 80-100°C; The annealing time is 5-10 minutes.

10. A perovskite solar cell comprising the hole transport layer according to claim 6 or 7.

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