Interface passivation layer, preparation method and perovskite solar cell

Abstract

This invention relates to an interface passivation layer, its preparation method, and a perovskite solar cell. The interface passivation layer is made of a polymeric ionic liquid; the cations of the polymeric ionic liquid include polymeric imidazolium cations containing sulfonamide substituents; and the anions of the polymeric ionic liquid include halide ions. The polymeric ionic liquid used in this invention has alkyl groups at its ends, exhibiting hydrophobicity and effectively preventing moisture from penetrating the perovskite film. The C-H groups in the imidazolium can form hydrogen bonds with halogen atoms in the perovskite film, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite. The sulfonyl group (O=S=O) effectively suppresses the influence of oxygen on the perovskite, extending the lifespan of the perovskite device. Furthermore, the amine group improves the coordination ability of the sulfonyl group and free cations, reducing vacancy defects in the perovskite film, thereby improving the photoelectric conversion efficiency.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and relates to an interface passivation layer, its preparation method, and a perovskite solar cell. Background Technology

[0002] With the continuous development of human society, the demand for energy is increasing. Traditional energy sources such as oil, natural gas, and coal are all non-renewable energy sources. Not only are their reserves dwindling, but they also cause serious pollution to the ecological environment. Therefore, the need to vigorously develop and utilize renewable and clean energy is becoming increasingly urgent and crucial. Solar energy, as a highly promising energy form, has significant advantages such as being inexhaustible, environmentally friendly, and readily available. Its application technology research and development has received widespread attention, and the development of clean, pollution-free, and abundant solar energy resources has become a research hotspot in the scientific research field. Organic-inorganic hybrid perovskite solar cells (PSCs) have developed rapidly since their emergence in 2009 due to their outstanding advantages such as low cost, high photoelectric conversion efficiency, and ease of industrial production. Their photoelectric conversion efficiency has rapidly increased to 27%.

[0003] The industrialization of perovskite crystals (PSCs) still faces the core challenge of long-term stability, a problem that needs to be effectively addressed before practical applications can be realized. It is well known that PSCs suffer from insufficient stability under harsh environments such as heat, light, and high humidity, which is a major bottleneck restricting their commercial application. Among these influencing factors, moisture is the most critical cause of PSC performance degradation. Water molecules readily form hydrogen bonds with non-coordinated iodine atoms on the perovskite surface. While this can suppress non-radiative recombination to some extent, water vapor further penetrates to the perovskite surface and grain boundaries, reacting with the perovskite material to generate reversible hydration products such as MAPbI3·H2O and MAPbI3·2H2O. The strong hydrogen bonding between water molecules and organic cations weakens the coordination bonding between organic cations and the inorganic PbI6 framework, which is the core mechanism of moisture-induced perovskite crystal structure degradation. Furthermore, moisture also promotes the protonation reaction of iodides, generating volatile hydrohalic acids, further exacerbating the decomposition of perovskite materials.

[0004] It is worth noting that while a low-humidity environment during the perovskite thin film deposition stage helps optimize the film morphology and carrier transport performance, moisture can still cause irreversible damage to the perovskite active layer during long-term device operation or in high-humidity environments. In particular, wide-bandgap perovskites (such as CsPbI3) used in tandem solar cells are especially sensitive to moisture; even trace amounts of moisture in the atmosphere can significantly accelerate their phase transition from a black photosensitive phase to a yellow non-photosensitive phase.

[0005] Therefore, there is a need for an interface passivation layer and a perovskite solar cell that can reduce vacancy defects in the perovskite film, passivate the defects in the perovskite film, and improve the photoelectric conversion efficiency. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide an interface passivation layer, a preparation method, and a perovskite solar cell. The interface passivation layer is made of a polymer ionic liquid, which, through specific selection of functional groups, can reduce vacancy defects in the perovskite film, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0007] To achieve this objective, the present invention employs the following technical solution:

[0008] In a first aspect, the present invention provides an interface passivation layer, wherein the material of the interface passivation layer includes a polymer ionic liquid;

[0009] The cations of the polymeric ionic liquid include polymeric imidazolium cations containing sulfonamide substituents;

[0010] The anions in the polymer ionic liquid include halide ions.

[0011] The interface passivation layer provided by this invention comprises a polymer ionic liquid, which has alkyl groups at its ends and exhibits hydrophobicity, effectively preventing water vapor from penetrating the perovskite film. The CH groups in the imidazole can form hydrogen bonds with halogen atoms in the perovskite film, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite. The sulfonyl group O=S=O can effectively suppress the influence of oxygen on the perovskite, extending the service life of the perovskite device. Moreover, the amine group improves the coordination ability of the sulfonyl group and free cations, reducing vacancy defects in the perovskite film and thus improving the photoelectric conversion efficiency.

[0012] In some embodiments, the polymeric ionic liquid has the following structural formula:

[0013] ;

[0014] Where X is any one or a combination of at least two of Cl, Br or I, m is an integer from 0 to 9, and n is from 30 to 80.

[0015] In some embodiments, the polymeric ionic liquid has the following structural formula:

[0016] .

[0017] In some embodiments, the method for preparing the polymer ionic liquid includes the following steps:

[0018] (1) p-Styrenesulfonyl chloride reacts with 3-bromopropylamine hydrobromide to give the first intermediate product;

[0019] The structural formula of the first intermediate product is as follows:

[0020] ;

[0021] (2) The first intermediate product reacts with poly-N-methylimidazole to obtain the second intermediate product;

[0022] The structural formula of the polyN-methylimidazolium is as follows:

[0023] ;

[0024] The structural formula of the second intermediate product is as follows:

[0025] , where m is an integer from 0 to 9.

[0026] (3) The second intermediate product is polymerized to obtain the polymer ionic liquid.

[0027] In some embodiments, the thickness of the interface passivation layer is 2nm to 5nm.

[0028] Secondly, the present invention provides a method for preparing an interface passivation layer, the method comprising the following steps:

[0029] The substrate surface is coated with an interface passivation liquid and annealed to obtain the interface passivation layer described in the first aspect.

[0030] The interface passivation solution contains a polymer ionic liquid.

[0031] In some embodiments, the concentration of the polymeric ionic liquid in the interface passivation solution is 1 mg / mL to 5 mg / mL.

[0032] In some embodiments, the annealing temperature is 80°C to 120°C.

[0033] In some embodiments, the annealing time is 10 min to 20 min.

[0034] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a carrier transport layer and a perovskite film layer;

[0035] An interface passivation layer as described in the first aspect is disposed between the charge carrier transport layer and the perovskite film layer.

[0036] In some embodiments, the perovskite solar cell includes a transparent conductive layer, a hole transport layer, an interface passivation layer, a perovskite film layer, an electron transport layer, and an electrode layer stacked together.

[0037] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The interface passivation layer provided by this invention comprises a polymer ionic liquid, which has alkyl groups at its ends and exhibits hydrophobicity, effectively preventing water vapor from penetrating the perovskite film. The CH groups in the imidazole can form hydrogen bonds with halogen atoms in the perovskite film, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite. The sulfonyl group O=S=O can effectively suppress the influence of oxygen on the perovskite, extending the service life of the perovskite device. Moreover, the amine group improves the coordination ability of the sulfonyl group and free cations, reducing vacancy defects in the perovskite film and thus improving the photoelectric conversion efficiency. Detailed Implementation

[0040] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0041] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0042] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0043] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0044] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0045] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0046] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0047] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0048] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0049] In this invention, "optional" means that something is optional, that is, it refers to either "with" or "without". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0050] In this invention, "room temperature" generally refers to 4℃~35℃, and can refer to 20℃±5℃. In some embodiments of this invention, room temperature refers to 20℃~30℃.

[0051] In a first aspect, the present invention provides an interface passivation layer, wherein the material of the interface passivation layer includes a polymer ionic liquid;

[0052] The cations of the polymeric ionic liquid include polymeric imidazolium cations containing sulfonamide substituents;

[0053] The anions in the polymer ionic liquid include halide ions.

[0054] The interface passivation layer provided by this invention comprises a polymer ionic liquid, which has alkyl groups at its ends and exhibits hydrophobicity, effectively preventing water vapor from penetrating the perovskite film. The CH groups in the imidazole can form hydrogen bonds with halogen atoms in the perovskite film, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite. The sulfonyl group O=S=O can effectively suppress the influence of oxygen on the perovskite, extending the service life of the perovskite device. Moreover, the amine group improves the coordination ability of the sulfonyl group and free cations, reducing vacancy defects in the perovskite film and thus improving the photoelectric conversion efficiency.

[0055] In some embodiments, the polymeric ionic liquid has the following structural formula:

[0056] ;

[0057] Where X is any one or a combination of at least two of Cl, Br or I, m is an integer from 0 to 9, and n is from 30 to 80.

[0058] Wherein, X is any one or at least two of Cl, Br, or I. Typical but non-limiting combinations include combinations of Cl and Br, combinations of Cl and I, combinations of Br and I, or combinations of Cl, Br, and I.

[0059] Where m is an integer from 0 to 9, for example, it can be 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9.

[0060] In some embodiments, the polymeric ionic liquid has the following structural formula:

[0061] .

[0062] In some embodiments, the method for preparing the polymer ionic liquid includes the following steps:

[0063] (1) p-Styrenesulfonyl chloride reacts with 3-bromopropylamine hydrobromide to give the first intermediate product;

[0064] The structural formula of the first intermediate product is as follows:

[0065] ;

[0066] (2) The first intermediate product reacts with poly-N-methylimidazole to obtain the second intermediate product;

[0067] The structural formula of the polyN-methylimidazolium is as follows:

[0068] ;

[0069] The structural formula of the second intermediate product is as follows:

[0070] , where m is an integer from 0 to 9.

[0071] (3) The second intermediate product is polymerized to obtain the polymer ionic liquid.

[0072] For example, the method for preparing the polymer ionic liquid includes:

[0073] S1. Preparation of p-styrenesulfonyl chloride: Under a nitrogen atmosphere and magnetic stirring at room temperature, thionyl chloride (SOCl2) was added dropwise to a round-bottom flask, followed by sodium styrenesulfonate. The round-bottom flask was then placed in an ice bath, and dry N,N-dimethylformamide (DMF) was slowly added using a syringe. The ice bath was then removed, and the mixture was stirred at room temperature under light-shielding conditions with aluminum foil. The crude product was extracted with diethyl ether, and the solvent was removed using a rotary evaporator to purify the product and obtain p-styrenesulfonyl chloride.

[0074] S2. Preparation of the first intermediate: 3-bromopropylamine hydrobromide and anhydrous dichloromethane (DCM) were added to a round-bottom flask and stirred magnetically until homogeneous. The round-bottom flask was placed in an ice bath, and p-styrene sulfonyl chloride was slowly added under a nitrogen atmosphere. Triethylamine (TEA) was then added dropwise, and the mixture was stirred at room temperature. The resulting mixture was extracted with saturated sodium chloride solution, and the organic phase was dried with anhydrous sodium sulfate. The mixture was then eluted and purified to obtain the first intermediate.

[0075] S3. Preparation of the second intermediate product: The first intermediate product, poly-N-methylimidazole and anhydrous acetonitrile are stirred and mixed in a round-bottom flask, concentrated under vacuum, and precipitated with diethyl ether to obtain the second intermediate product.

[0076] S4. Preparation of polymer ionic liquid: DMF and the second intermediate are mixed in a round-bottom flask, followed by the addition of 4-cyano-4-(dodecylthiocarbonyl)thioalkylpentanoic acid (CDTPA) and azobisisobutyronitrile (AIBN). The mixture is transferred to a Schlenk flask, deoxygenated, and purged with nitrogen. The mixture is then heated and stirred to proceed with the reaction. After the reaction is complete, the reaction mixture is diluted with acetone. The crude polymer is precipitated twice in a mixed solvent. The resulting polymer is collected by centrifugation and dried to obtain a dry polymer. The dry polymer is dissolved in 1,4-dioxane, and dilauryl peroxide (LPO) and AIBN are added. The mixture is heated under a nitrogen atmosphere. The reactants are precipitated and dispersed in hexane and dried to obtain the polymer ionic liquid.

[0077] In some embodiments, the thickness of the interface passivation layer is 2nm to 5nm, for example, it can be 2nm, 3nm, 4nm or 5nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0078] Secondly, the present invention provides a method for preparing an interface passivation layer, the method comprising the following steps:

[0079] The substrate surface is coated with an interface passivation liquid and annealed to obtain the interface passivation layer described in the first aspect.

[0080] The interface passivation solution contains a polymer ionic liquid.

[0081] In some embodiments, the concentration of the polymeric ionic liquid in the interface passivation solution is 1 mg / mL to 5 mg / mL, for example, it can be 1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL or 5 mg / mL, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0082] In some embodiments, the annealing temperature is 80°C to 120°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0083] In some embodiments, the annealing time is 10 min to 20 min, for example, it can be 10 min, 12 min, 15 min, 16 min, 18 min or 20 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0084] Thirdly, the present invention provides a perovskite solar cell, the perovskite solar cell comprising a carrier transport layer and a perovskite film layer;

[0085] An interface passivation layer as described in the first aspect is disposed between the charge carrier transport layer and the perovskite film layer.

[0086] In some embodiments, the perovskite solar cell includes a transparent conductive layer, a hole transport layer, an interface passivation layer, a perovskite film layer, an electron transport layer, and an electrode layer stacked together.

[0087] In some embodiments, the material in the perovskite film has the general formula ABN3, where A includes CH3NH3. + CH(NH2)2 + Cs + or Rb + B is any combination of one or at least two of the following, where B is Pb. 2+ Sn 2+ Or Ge 2+ Any one or at least two of the following, where N is any one or at least two of Cl, Br, or I.

[0088] In some embodiments, a perovskite precursor solution is used when preparing the perovskite film, wherein the solvent in the perovskite precursor solution can be any one or a combination of at least two of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), 1,3-dimethyl-2-imidazolinone (DMI), dimethylacetamide (DMAC), N,N-dimethylpropenylurea (DMPU), acetonitrile (CAN), or 2-mercaptoethanol (ME).

[0089] In some embodiments, the thickness of the perovskite film is 300 nm to 700 nm, for example, it can be 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, 550 nm, 600 nm, 650 nm or 700 nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0090] In some embodiments, the transparent conductive layer is made of any one or a combination of at least two of fluorine-doped tin oxide (FTO), tin-doped indium oxide (ITO), aluminum-doped zinc oxide (AZO), boron-doped zinc oxide (BZO), indium zinc oxide (IZO), or tungsten-doped indium oxide (IWO).

[0091] In some embodiments, the hole transport layer is made of a p-type semiconductor material, including any one or a combination of at least two of the following: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 4-butyl-N,N-diphenylaniline homopolymer (Ploy-TPD), polyvinylcarbazole (PVK), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz) and its derivatives, nickel oxide, CuI, or cuprous cyanate (CuSCN).

[0092] In some embodiments, the electron transport layer is made of an n-type semiconductor material, including C 60 [6,6]-phenyl–C 61 1-Methyl butyrate (PCBM), TiO2, SnO2, ZnO, or ZnO-ZnS, or a combination of at least two of these.

[0093] In some embodiments, the electrode layer is made of a conductive material, which may be a metallic conductive material and / or a conductive oxide; wherein the metallic conductive material may be any one or a combination of at least two of gold, silver, copper, aluminum, nickel, chromium, bismuth, platinum or magnesium; and the conductive oxide may be any one or a combination of at least two of FTO, ITO, IWO or AZO.

[0094] Preparation Example 1

[0095] This preparation example provides a polymeric ionic liquid with the following structural formula:

[0096] , where m is 5.

[0097] In this preparation example, the method for preparing the polymer ionic liquid includes:

[0098] S1. Preparation of p-styrenesulfonyl chloride: Under a nitrogen atmosphere and at room temperature with magnetic stirring, thionyl chloride (SOCl2, 25 mL, 345 mmol) was added dropwise to a round-bottom flask, followed by sodium styrenesulfonate (10.012 g, 28.557 mmol). The round-bottom flask was then placed in an ice bath, and dry N,N-dimethylformamide (DMF, 15 mL) was slowly added using a syringe. The ice bath was then removed, and the mixture was stirred at room temperature for 12 h under light-shielding conditions with aluminum foil. The crude product was extracted three times with diethyl ether, and the solvent was removed using a rotary evaporator to purify and obtain p-styrenesulfonyl chloride.

[0099] S2. Preparation of the first intermediate: 3-bromopropylamine hydrobromide (14.044 g, 0.064 mol) and anhydrous dichloromethane (DCM, 100 mL) were added to a round-bottom flask and stirred magnetically until homogeneous. The round-bottom flask was placed in an ice bath, and p-styrene sulfonyl chloride (9.95 g, 0.049 mol) was slowly added under a nitrogen atmosphere. Triethylamine (TEA, 13 mL, 0.093 mol) was then added dropwise, and the mixture was stirred at room temperature for 48 h. The resulting mixture was extracted three times with saturated sodium chloride solution, and the organic phase was dried with anhydrous sodium sulfate. The mixture was then eluted (using hexane and dichloromethane in a volume ratio of 1.5:1) and purified (by silica gel column chromatography) to obtain the first intermediate.

[0100] S3. Preparation of the second intermediate: The first intermediate (6.302 g, 0.021 mol), poly-N-methylimidazole (0.021 mol), and anhydrous acetonitrile (40 mL) were mixed in a round-bottom flask at 60 °C for 4 days. After vacuum concentration, the mixture was precipitated twice with diethyl ether to obtain the second intermediate.

[0101] The structural formula of poly-N-methylimidazole is: m is 5;

[0102] S4. Preparation of polymer ionic liquid: 3 mL of DMF and the second intermediate (5.816 mmol) were mixed in a round-bottom flask, followed by the addition of 4-cyano-4-(dodecylthiocarbonyl)thioalkylpentanoic acid (CDTPA, 0.047 g, 0.116 mmol) and azobisisobutyronitrile (AIBN, 0.005 g, 0.029 mmol). The mixture was transferred to a Schlenk flask, deoxygenated, and purged with nitrogen. The mixture was then stirred at 400 rpm for 42 h in an oil bath at 75 °C. After the reaction was complete, the reaction mixture was diluted with acetone, and the crude polymer was added to the mixed solvent (volume...). The polymer was precipitated twice in a mixture of water and acetone (1:0.05). The resulting polymer was collected by centrifugation and dried under vacuum at 70°C overnight to obtain a dried polymer. The dried polymer was dissolved in 200 mL of 1,4-dioxane, and dilauryl peroxide (LPO, 2.4001 g, 6.02 mmol) and AIBN (4.9435 g, 30.1 mmol) were added. The mixture was heated under a nitrogen atmosphere (80°C, 12 h). The precipitate of the reactants was dispersed in hexane and dried under vacuum at 70°C for 12 h to obtain the polymer ionic liquid. In the obtained polymer ionic liquid, the value of n is 40.

[0103] Preparation Example 2

[0104] This preparation example provides a polymeric ionic liquid, which is identical to Preparation Example 1 except that m is 0.

[0105] Preparation Example 3

[0106] This preparation example provides a polymeric ionic liquid, which is identical to Preparation Example 1 except that m is 9.

[0107] Preparation Example 4

[0108] This preparation example provides a polymeric ionic liquid, which is identical to Preparation Example 1 except that m is 12.

[0109] Example 1

[0110] This embodiment provides a perovskite solar cell, including a transparent conductive layer, a hole transport layer, an interface passivation layer, a perovskite film layer, an electron transport layer, and an electrode layer stacked together.

[0111] The fabrication method of the perovskite solar cell includes the following steps:

[0112] (1) The transparent conductive layer (FTO) was ultrasonically cleaned with detergent, deionized water, acetone and anhydrous ethanol respectively, and then dried with nitrogen gas; the ultrasonic cleaning power was 100 Hz and the time was 15 min.

[0113] (2) A hole transport layer is deposited on the surface of the transparent conductive layer by spin coating. Specifically, a hole transport layer solution with a concentration of 0.5 mg / mL prepared by [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (meo-2PACz) is dropped onto the surface of the transparent conductive layer and spin-coated at a speed of 3000 rpm for 30 s. Then, it is annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0114] (3) Dissolve the polymer ionic liquid provided in Preparation Example 1 in isopropanol to obtain a polymer ionic liquid solution with a concentration of 3 mg / mL; then spin coat the polymer ionic liquid solution onto the surface of the hole transport layer at a speed of 5000 rpm for 45 s, and then anneal at 100 °C for 15 min to obtain an interface passivation layer with a thickness of 4 nm.

[0115] (4) 108.33 mg CsI, 1218.34 mg FAI, 132.50 mg MAI, 4033.76 mg PbI2, and 83.27 mg MACl were added to a mixed solution containing 4200 μL DMF and 840 μL DMSO, and stirred thoroughly for 12 h to obtain a perovskite precursor solution with a concentration of 1.67 mol / L (CsI). 0.05 MA 0.1 FA 0.85PbI3); the perovskite precursor solution was spin-coated onto the surface of the interface passivation layer at a speed of 5000 rpm for 50 s, and 200 μL of chlorobenzene was added dropwise at the 35th s; finally, it was annealed at 120 °C for 15 min to obtain a perovskite film with a thickness of 450 nm.

[0116] (5) A solution of isopropanol containing piperazine monoiodine at a concentration of 0.3 mg / mL was spin-coated onto the surface of the perovskite film at a spin speed of 4000 rpm for 30 s, followed by annealing at 100 °C for 10 min to a thickness of 2 nm; then, an electron transport layer C was deposited by vacuum evaporation. 60 The vacuum degree of vacuum evaporation is 5×10⁻⁶. -4 Pa, evaporation rate of 0.15 Å / s, thickness of 20 nm;

[0117] (6) A BCP layer with a thickness of 8 nm is deposited on the surface of the electron transport layer by vacuum evaporation, wherein the vacuum degree of vacuum evaporation is 5 × 10⁻⁶. -4 Pa, evaporation rate is 0.2 Å / s;

[0118] (7) Finally, the electrode layer is prepared, specifically by forming a 100 nm thick silver electrode layer on the surface of the BCP layer through thermal evaporation, wherein the vacuum degree of thermal evaporation is 5 × 10⁻⁶. -4 Pa, evaporation rate is 2 angstroms / s.

[0119] Example 2

[0120] This embodiment provides a perovskite solar cell, which is the same as that in Example 1, except that the polymer ionic liquid in the polymer ionic liquid solution is provided by Preparation Example 2.

[0121] Example 3

[0122] This embodiment provides a perovskite solar cell, which is the same as that in Example 1, except that the polymer ionic liquid in the polymer ionic liquid solution is provided by Preparation Example 3.

[0123] Example 4

[0124] This embodiment provides a perovskite solar cell, which is the same as that in Example 1, except that the polymer ionic liquid in the polymer ionic liquid solution is provided by Preparation Example 4.

[0125] Example 5

[0126] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the concentration of the polymer ionic liquid solution is 1 mg / mL and the thickness of the interface passivation layer remains unchanged.

[0127] Example 6

[0128] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the concentration of the polymer ionic liquid solution is 5 mg / mL and the thickness of the interface passivation layer remains unchanged.

[0129] Example 7

[0130] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the concentration of the polymer ionic liquid solution is 0.5 mg / mL and the thickness of the interface passivation layer remains unchanged.

[0131] Example 8

[0132] This embodiment provides a perovskite solar cell, which is the same as in Example 1 except that the concentration of the polymer ionic liquid solution is 7 mg / mL and the thickness of the interface passivation layer remains unchanged.

[0133] Comparative Example 1

[0134] This comparative example provides a perovskite solar cell, which is the same as Example 1 except that it does not have an interface passivation layer. Specifically, it includes a transparent conductive layer, a hole transport layer, a perovskite film layer, an electron transport layer and an electrode layer stacked together.

[0135] The fabrication method of the perovskite solar cell includes the following steps:

[0136] (1) The transparent conductive layer (FTO) was ultrasonically cleaned with detergent, deionized water, acetone and anhydrous ethanol respectively, and then dried with nitrogen gas; the ultrasonic cleaning power was 100 Hz and the time was 15 min.

[0137] (2) A hole transport layer is deposited on the surface of the transparent conductive layer by spin coating. Specifically, a hole transport layer solution with a concentration of 0.5 mg / mL prepared by [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (meo-2PACz) is dropped onto the surface of the transparent conductive layer and spin-coated at a speed of 3000 rpm for 30 s. Then, it is annealed at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2 nm.

[0138] (3) 108.33 mg CsI, 1218.34 mg FAI, 132.50 mg MAI, 4033.76 mg PbI2 and 83.27 mg MACl were added to a mixed solution containing 4200 μL DMF and 840 μL DMSO and stirred thoroughly for 12 h to obtain a perovskite precursor solution with a concentration of 1.67 mol / L (CsI). 0.05 MA 0.1 FA 0.85PbI3); The perovskite precursor solution was spin-coated onto the surface of the hole transport layer at a speed of 5000 rpm for 50 s, and 200 μL of chlorobenzene was added dropwise at the 35th s; Finally, it was annealed at 120 °C for 15 min to obtain a perovskite film with a thickness of 450 nm.

[0139] (4) A solution of isopropanol containing piperazine monoiodine at a concentration of 0.3 mg / mL was spin-coated onto the surface of the perovskite film at a spin speed of 4000 rpm for 30 s, followed by annealing at 100 °C for 10 min to a thickness of 2 nm; then, an electron transport layer C was deposited by vacuum evaporation. 60 The vacuum degree of vacuum evaporation is 5×10⁻⁶. -4 Pa, evaporation rate of 0.15 Å / s, thickness of 20 nm;

[0140] (5) A BCP layer with a thickness of 8 nm is deposited on the surface of the electron transport layer by vacuum evaporation, wherein the vacuum degree of vacuum evaporation is 5 × 10⁻⁶. -4 Pa, evaporation rate is 0.2 Å / s;

[0141] (6) Finally, the electrode layer is prepared, specifically by forming a 100 nm thick silver electrode layer on the surface of the BCP layer through thermal evaporation, wherein the vacuum degree of thermal evaporation is 5 × 10⁻⁶. -4 Pa, evaporation rate is 2 angstroms / s.

[0142] Performance Characterization

[0143] The perovskite solar cells provided in the above embodiments and comparative examples were subjected to performance tests. The test conditions included: emitting standard sunlight (spectral AM 1.5G, effective active layer area of ​​1 cm²) using a solar simulator. 2 Incident power 100mW / cm 2 (At a temperature of 25℃), the test results are shown in Table 1.

[0144] Where Jsc is the short-circuit current density, Voc is the open-circuit voltage, PCE is the photoelectric conversion efficiency, and FF is the fill factor.

[0145] Table 1

[0146]

[0147] As shown in Table 1, the perovskite solar cells treated with the polymer ionic liquid of this invention exhibit significant improvements in open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency. Compared to carbon chain numbers of 0-9 (Examples 1, 2, and 3), a high carbon chain number (Example 4) significantly impacts the photoelectric conversion efficiency of the perovskite solar cell. This is because a high carbon chain number severely affects carrier transport, leading to a decrease in efficiency. Secondly, when the concentration of the polymer ionic liquid solution is too low (Example 7), the number of hydrogen bonds formed between CH in the polymer ionic liquid and halogen atoms in the perovskite decreases, and the sulfonyl O=S=O structure cannot effectively suppress the influence of oxygen on the perovskite, resulting in poor stability of the perovskite film and a decrease in photoelectric conversion efficiency. When the concentration of the polymer ionic liquid solution is too high (Example 9), stacking may form on the surface of the perovskite film, hindering carrier transport and affecting cell efficiency.

[0148] In summary, the material of the interface passivation layer provided by this invention includes a polymer ionic liquid. The polymer ionic liquid has alkyl groups at its ends, which have a certain degree of hydrophobicity and can effectively block the invasion of water vapor into the perovskite film. The CH in imidazole can form hydrogen bonds with halogen atoms in the perovskite film, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite. The sulfonyl group O=S=O can effectively suppress the influence of oxygen on the perovskite, extend the service life of the perovskite device, and the amine group improves the coordination ability of the sulfonyl group and free cations, reducing vacancy defects in the perovskite film, thereby improving the photoelectric conversion efficiency.

[0149] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An interface passivation layer, characterized in that, The material of the interface passivation layer includes a polymer ionic liquid; The cations of the polymeric ionic liquid include polymeric imidazolium cations containing sulfonamide substituents; The anions of the polymer ionic liquid include halide ions; The structural formula of the polymer ionic liquid is as follows: ； Where X is any one or a combination of at least two of Cl, Br or I, m is an integer from 0 to 9, and n is from 30 to 80.

2. The interface passivation layer according to claim 1, characterized in that, The structural formula of the polymer ionic liquid is as follows: 。 3. The interface passivation layer according to claim 1 or 2, characterized in that, The preparation method of the polymer ionic liquid includes the following steps: (1) p-Styrenesulfonyl chloride reacts with 3-bromopropylamine hydrobromide to give the first intermediate product; The structural formula of the first intermediate product is as follows: ； (2) The first intermediate product reacts with poly-N-methylimidazole to obtain the second intermediate product; The structural formula of the polyN-methylimidazolium is as follows: ； The structural formula of the second intermediate product is as follows: , where m is an integer from 0 to 9; (3) The second intermediate product is polymerized to obtain the polymer ionic liquid.

4. The interface passivation layer according to claim 1, characterized in that, The thickness of the interface passivation layer is 2nm~5nm.

5. A method for preparing an interface passivation layer, characterized in that, The preparation method includes the following steps: The substrate surface is coated with an interface passivation liquid and annealed to obtain the interface passivation layer as described in any one of claims 1 to 4; The interface passivation solution contains a polymer ionic liquid.

6. The preparation method according to claim 5, characterized in that, The concentration of the polymer ionic liquid in the interface passivation solution is 1 mg / mL to 5 mg / mL.

7. The preparation method according to claim 5 or 6, characterized in that, The annealing temperature is 80℃~120℃.

8. The preparation method according to claim 5 or 6, characterized in that, The annealing time is 10 min to 20 min.

9. A perovskite solar cell, characterized in that, The perovskite solar cell includes a carrier transport layer and a perovskite film layer; An interface passivation layer as described in any one of claims 1 to 4 is provided between the charge carrier transport layer and the perovskite film layer.

10. The perovskite solar cell according to claim 9, characterized in that, The perovskite solar cell includes a transparent conductive layer, a hole transport layer, an interface passivation layer, a perovskite film layer, an electron transport layer, and an electrode layer stacked together.

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