Perovskite solar cell and preparation method thereof

Abstract

The invention provides a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a substrate, and a transparent conductive layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer and an electrode which are sequentially stacked on the substrate, and the preparation method of the first carrier transport layer comprises the following steps: S1, modifying the surface of a metal oxide layer by adopting a low-temperature plasma process, the modified surface of the metal oxide layer comprises functional groups, and the functional groups comprise hydroxyl and amino; s2, preparing an organic self-assembly monomolecular layer on the modified surface of the metal oxide layer to obtain a first carrier transport layer; wherein the transparent conductive layer comprises a metal oxide layer, and the first carrier transport layer comprises an organic self-assembly monomolecular layer; or the first carrier transport layer comprises a metal oxide layer and an organic self-assembly monomolecular layer, and the metal oxide layer is arranged between the transparent conductive layer and the organic self-assembly monomolecular layer.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, specifically to a perovskite solar cell and its fabrication method. Background Technology

[0002] In recent years, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has been significantly improved, especially for inverted (pin-type) perovskite solar cells, which combine excellent PCE with low fabrication costs and process complexity, demonstrating broad application prospects. Currently, to realize large-area perovskite-silicon tandem photovoltaic devices, it is still necessary to further improve the performance stability of perovskite solar cells, particularly the performance stability of the carrier transport layer and its interfacial contact stability with the perovskite layer.

[0003] Inspired by dye-sensitized solar cells, organic self-assembled monolayers (SAMs) have been introduced as hole transport layers (HTLs) into inverted perovskite solar cells. SAMs, through the anchoring groups of their self-assembled monolayers, bind to the surface of the metal oxide substrate, promoting hole transport and extraction, reducing open-circuit voltage loss, and thus improving the performance of perovskite solar cells. However, organic self-assembled monolayers suffer from problems such as loose structure, easy aggregation, and uneven distribution on the substrate surface, leading to increased leakage current and negatively impacting photovoltaic device performance.

[0004] Therefore, enhancing the anchoring stability and distribution uniformity of SAMs, thereby improving the interfacial contact between the carrier transport layer and the perovskite layer, is crucial for further improving the performance of perovskite solar cells (especially large-area perovskite solar cells). Summary of the Invention

[0005] To enhance the anchoring stability and distribution uniformity of organic self-assembled monolayers, this application provides a perovskite solar cell and its fabrication method.

[0006] The first aspect of this application provides a method for fabricating a perovskite solar cell. The perovskite solar cell includes a substrate and a transparent conductive layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and an electrode sequentially stacked on the substrate. The method for fabricating the first carrier transport layer includes: step S1, modifying the surface of a metal oxide layer using a low-temperature plasma process, wherein the modified surface of the metal oxide layer includes functionalized groups, including hydroxyl and amino groups; step S2, fabricating an organic self-assembled monolayer on the modified surface of the metal oxide layer to obtain the first carrier transport layer; wherein the transparent conductive layer includes a metal oxide layer, and the first carrier transport layer includes an organic self-assembled monolayer (SAM); or, the first carrier transport layer includes a metal oxide layer and an organic self-assembled monolayer, wherein the metal oxide layer is disposed between the transparent conductive layer and the organic self-assembled monolayer.

[0007] In the above-mentioned method for fabricating perovskite solar cells, the metal oxide layer can serve as part of the first carrier transport layer or as a transparent conductive metal oxide layer. The surface of the metal oxide layer is modified using a low-temperature plasma (non-thermal plasma) process, enriching the surface with functionalized groups (hydroxyl and amino groups). The hydroxyl groups bond with the anchoring groups of the self-assembled monomolecules (SAMs), providing more anchoring sites for the SAMs and improving their anchoring strength and uniformity, thus modifying surface defects in the metal oxide layer. The amino groups effectively passivate surface defects in the metal oxide layer, improve the hydrophilicity of the metal oxide layer surface, and enhance the dispersion and adhesion stability of hydroxyl groups on the metal oxide layer surface. Therefore, under the combined effect of hydroxyl and amino groups, the degree of loose structure and uneven distribution of organic self-assembled monolayers is effectively controlled. The density and uniformity of SAM on the surface of metal oxide layer are improved simultaneously, the contact of buried interface is improved, thereby reducing leakage current and suppressing nonradiative recombination of charge carriers at the interface. It is also beneficial to the crystal quality and continuity of subsequent perovskite layers, and synergistically improves the photoelectric conversion efficiency of perovskite solar cells and the stability of photovoltaic devices.

[0008] In any embodiment of the first aspect, the plasma source used in the low-temperature plasma process includes at least water vapor and NH3.

[0009] In any embodiment of the first aspect, the volumetric flow rate ratio of water vapor to NH3 in the plasma gas source is 3:1 to 1:1.

[0010] In any embodiment of the first aspect, before performing step S1, the method for preparing the first carrier transport layer further includes: depositing a liquid film on the surface of the metal oxide layer, the liquid film including a water film or an ammonia film.

[0011] In any embodiment of the first aspect, when preparing the liquid film, the amount of liquid applied per unit area of ​​the metal oxide layer is 10 μL / cm. 2 - 50μL / cm 2 Preferably 19 μL / cm 2 - 25μL / cm 2 .

[0012] In any embodiment of the first aspect, for the case where the liquid film is a water film, the plasma gas source used in the low-temperature plasma process includes at least NH3; optionally, the volumetric flow rate of NH3 in the plasma gas source is 1 mL / min - 100 mL / min, and / or, the plasma gas source used in the low-temperature plasma process also includes at least one of rare gas and oxygen.

[0013] In any embodiment of the first aspect, for the case where the liquid film is an ammonia film, the plasma gas source used in the low-temperature plasma process includes at least one of water vapor, NH3, rare gas or oxygen; optionally, the volumetric flow rate of the plasma gas source is 1 mL / min - 100 mL / min.

[0014] In any embodiment of the first aspect, the low-temperature plasma process further includes one or more of the following process parameters: working power of 10W-100W, working temperature of 20℃-30℃, working pressure of 0.1Pa-100Pa, and working time of 1min-30min.

[0015] In any embodiment of the first aspect, where the transparent conductive layer comprises a metal oxide layer, the metal oxide layer of the transparent conductive layer comprises one or more of indium tin oxide, fluorine-doped tin oxide, zinc tin oxide, zinc-doped indium oxide, or tungsten-doped indium oxide.

[0016] In any embodiment of the first aspect, where the first carrier transport layer comprises a metal oxide layer and an organic self-assembled monolayer, the first carrier transport layer is a hole transport layer, and the metal oxide layer of the first carrier transport layer comprises one or more of nickel oxide, copper oxide, molybdenum oxide, vanadium oxide, tungsten oxide, or iridium oxide.

[0017] In any embodiment of the first aspect, where the first carrier transport layer comprises a metal oxide layer and an organic self-assembled monolayer, the first carrier transport layer is an electron transport layer, and the metal oxide layer of the first carrier transport layer comprises one or more of titanium dioxide, zinc oxide, or tin oxide.

[0018] In any embodiment of the first aspect, where the first carrier transport layer comprises a metal oxide layer and an organic self-assembled monolayer, the metal oxide layer comprising the first carrier transport layer is an annealed metal oxide layer; optionally, the annealing temperature is 100℃-500℃ and the annealing time is 5 min-60 min.

[0019] In any embodiment of the first aspect, the aforementioned organic self-assembled monolayer includes an anchoring group, which includes one or more of phosphonic acid, carboxylic acid, cyanophosphonic acid, or cyanoacetic acid groups.

[0020] In any embodiment of the first aspect, the aforementioned organic self-assembled monolayer comprises [2] (9H carbazole 9 [4]ethylphosphonic acid, [4] (9H carbazole 9 base) [Butyl]phosphonic acid, [4] (3,6 dimethyl 9H carbazole 9 [4]butylphosphonic acid, [4] (3,6 Dimethoxy 9H carbazole 9 [4] Butylphosphonic acid, poly[4] (9H carbazole 9 base) Butylphosphonic acid, poly[2] (9H carbazole 9 [4]ethylphosphonic acid or [4] (7H Dibenzo[c, g]carbazole 7 One or more of [butylphosphonic acid].

[0021] In any embodiment of the first aspect, step S2 includes: coating a self-assembled monomolecular material solution onto the modified surface of the metal oxide and then annealing it; optionally, the annealing temperature is 60°C-150°C and the time is 5-30 min, more preferably, the annealing temperature is 80°C-120°C and the time is 5-20 min.

[0022] The second aspect of this application provides a perovskite solar cell, which is prepared according to any of the perovskite solar cell preparation methods provided in the first aspect above. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell in one embodiment of this application;

[0025] Figure 2 This is a schematic diagram of the structure of a perovskite solar cell according to another embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Substrate; 2. Transparent conductive layer; 3a. Metal oxide layer; 3b. Organic self-assembled monolayer; 4. Perovskite layer; 5. Passivation layer; 6. Second carrier transport layer; 7. Interface modification layer; 8. Electrode. Detailed Implementation

[0028] The embodiments of this application will be described in further detail below with reference to the examples. The detailed description of the following embodiments is used to illustrate the principles of this application, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0029] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0030] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0031] Unless otherwise specified, the terms "comprising" and "having" and any variations thereof are open expressions that include the contents specified in this application, but do not exclude contents not mentioned.

[0032] The perovskite solar cell fabrication method provided in this application is not only applicable to single-junction perovskite solar cells, but also to tandem solar cells. Tandem solar cells can be crystalline silicon / perovskite tandem solar cells, all-perovskite tandem solar cells, organic photovoltaic / perovskite tandem solar cells, etc.

[0033] In existing technologies, self-assembled monolayers (SAMs) bind to the surface of metal oxide layers through anchoring groups, promoting hole transport and extraction, reducing open-circuit voltage loss, and thus improving the performance of perovskite solar cells. However, organic self-assembled monolayers suffer from problems such as loose structure, easy aggregation, and uneven distribution on the surface of metal oxide layers, leading to increased leakage current and limiting the improvement of photoelectric conversion efficiency of perovskite solar cells. Therefore, enhancing the anchoring stability and distribution uniformity of SAMs, thereby modifying interface defects, improving interface contact, and reducing non-radiative recombination of charge carriers and leakage current, is crucial for improving the performance of perovskite solar cells (especially large-area perovskite solar cells).

[0034] In a first embodiment of this application, a method for fabricating a perovskite solar cell is provided. The perovskite solar cell includes a substrate and a transparent conductive layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and an electrode sequentially stacked on the substrate. The method for fabricating the first carrier transport layer includes: step S1, modifying the surface of a metal oxide layer using a low-temperature plasma process, wherein the modified surface of the metal oxide layer includes functionalized groups, including hydroxyl and amino groups; step S2, fabricating an organic self-assembled monolayer (hereinafter referred to as SAM) on the modified surface of the metal oxide layer to obtain the first carrier transport layer; wherein the transparent conductive layer includes a metal oxide layer, and the first carrier transport layer includes an organic self-assembled monolayer; or, the first carrier transport layer includes a metal oxide layer and an organic self-assembled monolayer, wherein the metal oxide layer is disposed between the transparent conductive layer and the organic self-assembled monolayer.

[0035] In the above-mentioned method for fabricating perovskite solar cells, the metal oxide layer can serve as part of the first carrier transport layer or as a transparent conductive metal oxide layer. The surface of the metal oxide layer is modified using a low-temperature plasma (non-thermal plasma) process, enriching the surface with functionalized groups (hydroxyl and amino groups). The hydroxyl groups bond with the anchoring groups of the self-assembled monomolecules (SAMs), providing more anchoring sites for the SAMs and improving their anchoring strength and uniformity, thus modifying surface defects in the metal oxide layer. The amino groups effectively passivate surface defects in the metal oxide layer, improve the hydrophilicity of the metal oxide layer surface, and enhance the dispersion and adhesion stability of hydroxyl groups on the metal oxide layer surface. Therefore, under the combined effect of hydroxyl and amino groups, the degree of loose structure and uneven distribution of organic self-assembled monolayers is effectively controlled. The density and uniformity of SAM on the surface of metal oxide layer are improved simultaneously, the contact of buried interface is improved, thereby reducing leakage current and suppressing nonradiative recombination of charge carriers at the interface. It is also beneficial to the crystal quality and continuity of subsequent perovskite layers, and synergistically improves the photoelectric conversion efficiency of perovskite solar cells and the stability of photovoltaic devices.

[0036] In this application, the mechanism of the low-temperature plasma process is roughly as follows: The plasma source is ionized in a high-frequency electric field to generate plasma. The high-energy particles and free radicals in the plasma greatly increase the mass exchange coefficient and chemical reaction rate. The low-temperature plasma acts on the surface of the metal oxide layer, achieving surface modification of the metal oxide layer through complex physicochemical interactions (mass exchange and energy transfer). It should be noted that the surface modification effect of the aforementioned low-temperature plasma only occurs in the surface region of the metal oxide layer, and therefore does not affect the inherent properties of the substrate.

[0037] In some embodiments, the plasma source used in the low-temperature plasma process includes at least water vapor and NH3. Water vapor and NH3, as reactive gases, generate hydroxyl and amino radicals that accumulate on the surface of the metal oxide layer, efficiently forming functionalized groups on the surface. Optionally, the plasma source also includes one or more of rare gases (such as argon) and oxygen. Rare gases (such as argon), as non-reactive gases, do not chemically react with the surface of the metal oxide layer after ionization. However, they transfer energy through inelastic collisions with the material surface and gas molecules, potentially causing the breaking of chemical bonds, the formation of active sites and active species, thereby indirectly driving surface chemical reactions and promoting the uniform dispersion of free radicals on the surface of the metal oxide layer. Oxygen can generate oxygen radicals, which helps to increase the hydrophilicity of the metal oxide layer surface, thereby increasing the amount and adhesion strength of hydroxyl groups on the surface of the metal oxide layer.

[0038] In some embodiments, the volumetric flow rate ratio of water vapor to NH3 in the plasma gas source is 3:1 to 1:1. The proportion of hydroxyl and amino groups in the newly functionalized groups on the surface of the metal oxide layer can be adjusted by changing the ratio of water vapor to NH3 in the plasma gas source. Exemplarily, the volumetric flow rate ratio of water vapor to NH3 in the plasma gas source can be 3:1, 2.5:1, 2:1, 1.5:1, 1:1, etc., but is not limited to these.

[0039] In some embodiments, before performing step S1, the method for preparing the first carrier transport layer further includes: setting a liquid film on the surface of the metal oxide layer, the liquid film including a water film or an ammonia film, the molecules in the liquid film can provide functional groups under the action of high-energy plasma, the liquid film can provide hydroxyl groups when it is a water film, and can provide both hydroxyl and amino groups when it is an ammonia film.

[0040] In some embodiments, when preparing the liquid film, the amount of liquid applied per unit area of ​​the metal oxide layer is 10 μL / cm². 2 - 50μL / cm 2 Preferably 19 μL / cm 2 - 25μL / cm 2 For example, the liquid application rate per unit area of ​​the metal oxide layer is 10 μL / cm. 2 15μL / cm 2 19μL / cm 2 20μL / cm 2 24μL / cm 2 25μL / cm 2 30μL / cm 2 50μL / cm 2 Or the range formed by any two of the above.

[0041] The liquid film described above can be applied to the surface of a metal oxide by spin coating or spray coating. This application does not limit the specific preparation method of the liquid film, and those skilled in the art can select and adjust it according to actual needs.

[0042] In some embodiments, the liquid film is an aqueous film, and the plasma source used in the low-temperature plasma process includes at least NH3, with a volumetric flow rate of NH3 ranging from 1 mL / min to 100 mL / min. After treatment by the low-temperature plasma process, NH3 generates high-energy particles and amino radicals. These high-energy particles bombard H2O molecules in the liquid film to produce hydroxyl groups, thereby simultaneously obtaining functionalized hydroxyl and amino groups. For example, the volumetric flow rate of NH3 in the plasma source can be 1 mL / min, 5 mL / min, 20 mL / min, 40 mL / min, 50 mL / min, 70 mL / min, 90 mL / min, 100 mL / min, or any range formed by both of the above. A volumetric flow rate of NH3 within the above range can balance process adjustability and surface defect passivation effects.

[0043] In some embodiments, the liquid film is a water film, and the plasma gas source used in the low-temperature plasma process also includes at least one of rare gas (such as argon) and oxygen, and the rare gas (such as argon) and oxygen have the same functions as described above.

[0044] In some embodiments, the liquid film is an ammonia film, and the plasma source used in the cryogenic plasma process includes at least one of water vapor, NH3, a rare gas (such as argon), or oxygen. For non-reactive gases, such as rare gases, plasma is generated after treatment by the cryogenic plasma process, and the high-energy particles in the plasma bombarding the ammonia film can form functionalized groups (i.e., hydroxyl and amino groups). When the plasma source includes water vapor and / or NH3, the active species generated by the ionization of the water vapor and / or NH3 in the plasma source can also provide functionalized groups.

[0045] In some embodiments, the liquid membrane is an ammonia membrane, and the volumetric flow rate of the plasma gas source is 1 mL / min to 100 mL / min. For example, the volumetric flow rate of the plasma gas source can be 1 mL / min, 5 mL / min, 20 mL / min, 40 mL / min, 50 mL / min, 70 mL / min, 90 mL / min, 100 mL / min, or any range formed by both of the above. A volumetric flow rate of the plasma gas source within the above range is beneficial for achieving both high plasma stability and sufficient concentration of active species, thereby improving processing efficiency.

[0046] In some embodiments, the low-temperature plasma process further includes one or more of the following process parameters: operating power of 10W-100W, operating temperature of 20℃-30℃, operating pressure of 0.1Pa-100Pa, and operating time of 1min-30min.

[0047] The power of cryogenic plasma treatment directly determines the degree of gas dissociation and the depth of surface modification. As the treatment power increases, gas dissociation becomes more complete, and the concentration of highly reactive species increases. However, excessively high power may lead to concentrated local discharges, disrupting plasma uniformity and easily causing surface damage to the metal oxide layer. In some embodiments, the power of cryogenic plasma treatment is 10 W-100 W. Within the range of processing power (W), significant surface modification effects can be achieved. When a liquid film is formed on the surface of the metal oxide layer, the processing power can be slightly higher than when the metal oxide layer does not have a liquid film.

[0048] In some embodiments, the duration of the cryogenic plasma treatment is 1 min to 30 min. For example, the duration of the cryogenic plasma treatment can be 1 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, or any range formed by both of the above.

[0049] In some embodiments, where the transparent conductive layer includes a metal oxide layer, the metal oxide layer may be one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), zinc tin oxide (ZTO), zinc-doped indium oxide (IZO), or tungsten-doped indium oxide (IWO). The aforementioned metal oxide layer serves as the transparent conductive layer, and the SAM (Screen Atomizer) is disposed on the surface of any of these transparent conductive layers. The SAM itself acts as a hole transport layer, and its thickness is typically 1 nm to 2 nm, offering advantages such as low material consumption and low parasitic absorption.

[0050] In some embodiments, where the first carrier transport layer comprises a metal oxide layer and an organic self-assembled monolayer, and the first carrier transport layer is a hole transport layer, the metal oxide layer comprising the first carrier transport layer comprises one or more of nickel oxide, copper oxide, molybdenum oxide, vanadium oxide, tungsten oxide, or iridium oxide.

[0051] In some embodiments, where the first carrier transport layer comprises a metal oxide layer and an organic self-assembled monolayer, and the first carrier transport layer is an electron transport layer, the metal oxide layer comprising the first carrier transport layer comprises one or more of titanium dioxide, zinc oxide, or tin oxide.

[0052] As an example, a perovskite solar cell has an inverted structure (pin structure), with a first carrier transport layer being a hole transport layer and a second carrier transport layer being an electron transport layer. The hole transport layer is formed by depositing an organic self-assembled monolayer on the surface of a metal oxide layer. In other embodiments, a perovskite solar cell has a formal structure (nip structure), with a first carrier transport layer being an electron transport layer and a second carrier transport layer being a hole transport layer. The electron transport layer is formed by depositing an organic self-assembled monolayer on the surface of a metal oxide layer.

[0053] Regardless of whether the first carrier transport layer is a hole transport layer or an electron transport layer, the combination of an organic self-assembled monolayer and a metal oxide layer to form the first carrier transport layer has the following advantages: On the one hand, thanks to the presence of the metal oxide layer, the first carrier transport layer has relatively better thermal stability and mechanical strength, making it suitable for fabricating large-area perovskite solar cells; on the other hand, the thickness of the first carrier transport layer is greater than that of a first carrier transport layer composed solely of an organic self-assembled monolayer, which greatly reduces the risk of direct contact between the perovskite layer and the transparent conductive layer, thus reducing leakage current.

[0054] In some embodiments, the metal oxide layer comprising the first carrier transport layer may be prepared by any one of spin coating, spray coating, blade coating, slot coating, thermal evaporation, atomic layer deposition (ALD) or physical vapor deposition (PVD), but is not limited thereto.

[0055] In some embodiments, where the first carrier transport layer comprises a metal oxide layer and an organic self-assembled monolayer, the metal oxide layer of the first carrier transport layer is an annealed metal oxide layer. Optionally, the annealing temperature is 100℃-500℃, and the annealing time is 5 min-60 min. Annealing improves the crystallinity of the metal oxide layer, reduces defects, and removes precursor impurities. Those skilled in the art can select a specific annealing temperature and duration based on the specific type of metal oxide used.

[0056] In some embodiments, the above-mentioned organic self-assembled monolayer is formed by coating a self-assembled monomolecular material solution onto the modified surface of the metal oxide layer, wherein the coating method is selected from any one of spin coating, spray coating, blade coating, slot coating or chemical bath deposition.

[0057] In some embodiments, the concentration of the self-assembled monomolecular material solution is 0.1 g / L to 5 g / L. For example, the concentration of the self-assembled monomolecular material solution can be 0.1 g / L, 0.5 g / L, 1 g / L, 2.5 g / L, 3 g / L, 4 g / L, 5 g / L, or any numerical range formed by both of the above.

[0058] In some embodiments, the solvent for the self-assembled monomolecular material solution is selected from any one or more of ethanol, methanol, isopropanol, chloroform, or dimethyl sulfoxide.

[0059] In some embodiments, the organic self-assembled monolayer includes an anchoring group selected from one or more phosphonic acid groups, carboxylic acid groups, cyanophosphonic acid groups, or cyanoacetic acid groups. The organic self-assembled monolayer is attached to the surface of the metal oxide layer through various physical or chemical interactions between the anchoring group and the functional groups on the surface of the metal oxide layer.

[0060] For example, when the anchoring group is a phosphonic acid group and the metal oxide is nickel oxide, a strong PO-Ni bond can be obtained by coordinating the hydroxyl group in the phosphonic acid group with the hydroxyl group on the surface of the metal oxide and then dehydrating and condensing to form a bridging oxygen. Alternatively, a deprotonated phosphonic acid oxygen atom can be formed by reacting with the Ni atom on the surface of the nickel oxide. 2+ Coordination bonds are formed; uncoordinated oxygen atoms may form hydrogen bonds with hydroxyl groups on the nickel oxide surface. The hydroxyl groups on the metal oxide surface bond with anchoring groups, providing richer anchoring sites for organic self-assembled monolayers. Combined with the multiple coordination capabilities of the aforementioned anchoring groups, the anchoring stability of SAM is significantly enhanced, and the interfacial charge transport efficiency is further improved.

[0061] In some embodiments, the organic self-assembled monolayer includes [2] (9H carbazole 9 [4]ethylphosphonic acid (2PACz), [4] (9H carbazole 9 base) Butylphosphonic acid (4PACz), [4 (3,6 dimethyl 9H carbazole 9 [Me]butylphosphonic acid (Me) 4PACz), [4 (3,6 Dimethoxy 9H carbazole 9 [MeO]butylphosphonic acid (MeO) 4PACz), poly[4 (9H carbazole 9 base) Butylphosphonic acid (Poly) 4PACz), poly[2 (9H carbazole 9 [Poly(ethyl)phosphonic acid] 2PACz) or [4 (7H Dibenzo[c, g]carbazole 7 One or more of [4PADCB](butyl)phosphonic acid. Those skilled in the art can select self-assembled monomolecular organic materials that match the physicochemical properties of adjacent layers based on factors such as the work function and surface roughness of the metal oxide layer, and the type of surface defects in the perovskite layer or metal oxide layer.

[0062] In some embodiments, step S2 includes: coating a self-assembled monomolecular material solution onto the modified surface of the metal oxide and then annealing it.

[0063] After coating a self-assembled monomolecular material solution onto a metal oxide surface rich in functionalized groups, annealing is performed to form covalent and coordination bonds between the self-assembled monomolecular material and the functionalized groups on the metal oxide layer surface. This reduces pinhole defects caused by uneven local dispersion of the self-assembled monomolecular material, resulting in a more robust and denser organic self-assembled monolayer. It should be further noted that excessively low annealing temperatures or short annealing times firstly increase the risk of incomplete self-assembly and weak anchoring, severely affecting the density of the organic self-assembled monolayer; secondly, solvent residue affects the subsequent crystallization of perovskite. Excessively high annealing temperatures or long annealing times can easily induce the decomposition or desorption of the organic self-assembled monomolecular material, which is detrimental to the performance of perovskite solar cells. Therefore, to ensure the overall performance of perovskite solar cells, the annealing process conditions of the organic self-assembled monolayer need to be carefully controlled during the fabrication process.

[0064] In some embodiments, the annealing temperature is 60°C-150°C and the time is 5 min-30 min. Optionally, the annealing temperature is 80°C-120°C and the time is 5-20 min. Controlling the annealing temperature and time within the above range can greatly reduce the risk of overheating decomposition of the organic self-assembled monolayer and minimize damage to the hydroxyl groups on the surface of the metal oxide layer. For example, after coating the self-assembled monolayer material solution onto the surface of the modified metal oxide, the annealing temperature can be 60°C, 70°C, 80°C, 90°C, 100°C, 120°C, 150°C, or any combination thereof, and the annealing time can be 5 min, 7 min, 10 min, 12 min, 15 min, 20 min, 30 min, or any combination thereof.

[0065] In some embodiments, a schematic diagram of the perovskite solar cell is shown below. Figure 1 The perovskite solar cell includes a substrate 1, a transparent conductive layer 2, a first carrier transport layer (e.g., including a metal oxide layer 3a and an organic self-assembled monolayer 3b), a perovskite layer 4, a passivation layer 5 (optional structure), a second carrier transport layer 6, an interface modification layer 7 (optional structure), and an electrode 8, which are stacked sequentially.

[0066] In some embodiments, a schematic diagram of the perovskite solar cell is shown below. Figure 2 The perovskite solar cell comprises, from bottom to top, a substrate 1, a transparent conductive layer 2, a first carrier transport layer (e.g., an organic self-assembled monolayer 3b), a perovskite layer 4, a passivation layer 5 (optional structure), an electron transport layer 6, an interface modification layer 7 (optional structure), and an electrode 8.

[0067] In some embodiments, the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer, and the perovskite solar cell has an inverted structure (pin structure); in other embodiments, the first carrier transport layer is an electron transport layer and the second carrier transport layer is a hole transport layer, and the perovskite solar cell has a formal structure (nip structure).

[0068] In some embodiments, substrate 1 includes any one of transparent glass, polyimide (PI), polyethylene terephthalate (PET), polypropylene (PP), polyethylene naphthalate (PEN), and silicon-based batteries.

[0069] In some embodiments, the transparent conductive layer 2 includes any one or more of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), zinc tin oxide (ZTO), zinc-doped indium oxide (IZO), and tungsten-doped indium oxide (IWO).

[0070] In some embodiments, the perovskite layer 4 comprises a perovskite material ABX3, wherein A comprises CH(NH2)2. + CH3NH3 + 、Rb + Cs + At least one of them, B includes Pb 2+ Sn 2+ Cu 2+ Zn 2+ Ca 2+ Ga 2+ At least one of them, X includes Cl - ,Br - I - F - SCN - At least one of them.

[0071] In some embodiments, the composition of the passivation layer 5, the second carrier transport layer 6, the interface modification layer 7, and the electrode 8 can all be referenced by conventional means, and will not be described in detail in this application.

[0072] It should be noted that the above schematic diagram of the perovskite solar cell is illustrative and is intended to help people understand the technical solution of this application more clearly. It should not be regarded as an unnecessary limitation on this application. People skilled in the art can make adjustments or changes without departing from the spirit and scope of this application, such as omitting the above passivation layer 5.

[0073] The second embodiment of this application provides a perovskite solar cell, which is obtained by any of the perovskite solar cell fabrication methods in the first embodiment. In the perovskite solar cell, the SAM (Solid Atomium) has high density and uniform distribution on the surface of the metal oxide layer, improving the contact at the buried interface. Consequently, the crystal quality and continuity of the perovskite layer are better, the non-radiative recombination degree of carriers at the interface is reduced, and the leakage current is decreased, thus synergistically improving the photoelectric conversion efficiency of the perovskite solar cell and the stability of the photovoltaic device.

[0074] The beneficial effects of this application will be further illustrated below with reference to embodiments and comparative examples, but the scope of the present invention is not limited to these embodiments.

[0075] Example 1

[0076] In this embodiment, the method for fabricating a perovskite solar cell includes:

[0077] S10. The glass substrate with the ITO transparent conductive layer on its surface is cleaned in glass detergent, ethanol, deionized water, acetone, isopropanol and ethanol for 15 minutes each, then dried by purging with nitrogen, and cleaned with ultraviolet ozone for 15 minutes to obtain a clean ITO transparent conductive layer on the glass substrate.

[0078] S11. A nickel oxide (NiOx) layer with a thickness of 20 nm was prepared on the ITO transparent conductive layer by magnetron sputtering, and then annealed at a temperature of 150 °C for 15 min to obtain the first hole transport layer.

[0079] S12. Using water vapor and ammonia (NH3) as a mixed gas source, the surface of the first hole transport layer (i.e., the annealed nickel oxide layer) is subjected to low-temperature plasma treatment. During the low-temperature plasma treatment, the volumetric flow rate of water vapor is 30. The volumetric flow rate of NH3 was 10 mL / min, the initial temperature of the low-temperature plasma treatment was room temperature (25℃), the pressure range was 0.1-10 Pa, the power was 50 W, and the duration was 10 min, resulting in a nickel oxide layer with hydroxyl and amino groups on the surface.

[0080] S20, 1mg of [2] (9H carbazole 9 [2PACz]ethylphosphonic acid (2PACz) was dissolved in 1 mL of anhydrous ethanol and stirred thoroughly to obtain a self-assembled monomolecular solution with a concentration of 1 g / L.

[0081] S21. A self-assembled monomolecular solution is coated onto the surface of the first hole transport layer after treatment in S12 by spin coating. Specifically, 50 μL of the above self-assembled monomolecular solution is added dropwise, and spin coating is performed at 4000 rpm for 30 s. Then, annealing is performed at 100°C for 10 minutes to obtain an organic self-assembled monolayer (SAM). The first hole transport layer and the organic self-assembled monolayer together form the hole transport layer.

[0082] S30, 113.67mg CsI, 192.68mg PbBr2, 225.71 mg FAI and 564.74mg PbI2 was dissolved in 1 mL of a mixed solvent consisting of dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio of 4:1. After stirring on a stirring table for 2 hours, a perovskite precursor solution was obtained.

[0083] S31. In a glove box under a nitrogen atmosphere, 90 μL of perovskite precursor solution was dropped onto the self-assembled monolayer and spin-coated at 6000 rpm for 60 s. In the last 20 s, 200 μL of chlorobenzene was dropped. After spin-coating with a spin coater, the perovskite layer was annealed on a hot plate for 20 min at a temperature of 100℃.

[0084] S40. Ethylenediamine dihydroiodide (EDAI) was used as a passivation material and dissolved in isopropanol (IPA). A passivation layer was prepared on the surface of the perovskite layer by spin coating. The spin coating parameters were: coating amount of 50 μL, spin coating speed of 3000 rpm, and spin coating time of 30 s.

[0085] S41, Using fullerene (C 60 As an electron transport material, C is deposited using a vacuum thermal evaporation process. 60 An electron transport layer with a thickness of 20 nm was deposited onto the surface of the passivation layer.

[0086] S42. Using copper bath (BCP) as a hole blocking material, BCP is deposited onto the surface of the electron transport layer by vacuum thermal evaporation to obtain a hole blocking layer (i.e., interface modification layer) with a thickness of 5 nm.

[0087] S43. Prepare 110 on the surface of the hole blocking layer by vacuum thermal evaporation. A perovskite solar cell was obtained by using an Ag metal electrode with a diameter of nm.

[0088] Example 2

[0089] The only difference between this embodiment and Embodiment 1 is that:

[0090] S12. First, an ammonia film is prepared on the surface of the first hole transport layer (i.e., the annealed nickel oxide layer) using a spin-coating method, and 120 μL of ammonia water is added dropwise. μL of NH3·H2O solution, spin-coated at a speed of 5000 rpm. The spin coating speed was rpm, the spin coating time was 30 seconds, and the spin coating area was 6.25 cm². 2 Subsequently, argon (Ar) was used as the plasma source for low-temperature plasma treatment. The volumetric flow rate of argon was 40 mL / min. The initial temperature of the low-temperature plasma treatment was room temperature (25℃), the pressure range was 0.1-10 Pa, the power was 50 W, and the duration was 10 min, resulting in a nickel oxide layer with hydroxyl and amino groups on the surface.

[0091] The remaining operations and settings are consistent with those in Example 1.

[0092] Example 3

[0093] The only difference between this embodiment and Embodiment 1 is that:

[0094] S12. First, a water film is prepared on the surface of the first hole transport layer (i.e., the annealed nickel oxide layer) using a spin-coating method, and 120 μL of water is added dropwise. μL of pure water, spin-coated at a speed of 5000 rpm. The spin coating speed was rpm, the spin coating time was 30 seconds, and the spin coating area was 6.25 cm². 2 Subsequently, NH3 and argon were used as plasma sources for low-temperature plasma treatment. The volumetric flow rate of NH3 was 30 mL / min, the volumetric flow rate of argon was 10 mL / min, the initial temperature of the low-temperature plasma treatment was room temperature (25℃), the pressure range was 0.1-10 Pa, the power was 50 W, and the duration was 10 min, resulting in a nickel oxide layer with hydroxyl and amino groups on the surface.

[0095] The remaining operations and settings are consistent with those in Example 1.

[0096] Example 4

[0097] The only difference between this embodiment and Embodiment 1 is that:

[0098] After obtaining the transparent conductive layer according to step S10, step S11 is not performed.

[0099] S12. Using water vapor and NH3 as a mixed gas source, the surface of the above transparent conductive layer is subjected to low-temperature plasma treatment. During the low-temperature plasma treatment, the volumetric flow rate of water vapor is 30 mL / min, the volumetric flow rate of NH3 is 10 mL / min, the initial temperature of the low-temperature plasma treatment is room temperature (25℃), the pressure range is 0.1-10 Pa, the power is 50 W, and the duration is 10 min, to obtain an ITO transparent conductive layer with hydroxyl and amino groups on the surface.

[0100] S20, 1mg of [2] (9H carbazole 9 [2PACz]ethylphosphonic acid (2PACz) was dissolved in 1 mL of anhydrous ethanol and stirred thoroughly to obtain a self-assembled monomolecular solution with a concentration of 1 g / L.

[0101] S21. A self-assembled monomolecular solution is coated onto the surface of the ITO transparent conductive layer after S12 by spin coating. Specifically, 50 μL of the above self-assembled monomolecular solution is added dropwise, and spin coating is performed at 4000 rpm for 30 s. Then, annealing is performed at 100°C for 10 minutes to form an organic self-assembled monomolecular layer, which serves as a hole transport layer.

[0102] Subsequent operations and settings remain the same as in Example 1.

[0103] Example 5

[0104] The only difference between this embodiment and Embodiment 1 is that:

[0105] After obtaining the transparent conductive layer according to step S10, step S11 is not performed.

[0106] S12. First, a water film is prepared on the surface of the transparent conductive layer using spin coating. Specifically, 120 μL of pure water is added dropwise, and the spin coating speed is 5000 rpm. The spin coating speed was rpm, the spin coating time was 30 seconds, and the spin coating area was 6.25 cm². 2 Subsequently, NH3 and argon were used as plasma sources for low-temperature plasma treatment. The volumetric flow rate of NH3 was 30 mL / min, and the volumetric flow rate of argon was 10 mL / min. The plasma flow rate was mL / min, the initial temperature for low-temperature plasma treatment was room temperature (25℃), the pressure range was 0.1-10 Pa, and the power was 50 mL / min. W, duration is 10 min, to obtain an ITO transparent conductive layer with surface rich in hydroxyl and amino groups;

[0107] S20, 1mg of [2] (9H carbazole 9 [2PACz]ethylphosphonic acid (2PACz) was dissolved in 1 mL of anhydrous ethanol and stirred thoroughly to obtain a self-assembled monomolecular solution with a concentration of 1 g / L.

[0108] S21. A self-assembled monomolecular solution is coated onto the surface of the ITO transparent conductive layer after S12 by spin coating. Specifically, 50 μL of the above self-assembled monomolecular solution is added dropwise, and spin coating is performed at 4000 rpm for 30 s. Then, annealing is performed at 100°C for 10 minutes to form an organic self-assembled monomolecular layer (SAM). This organic self-assembled monomolecular layer serves as a hole transport layer.

[0109] Subsequent operations and settings remain the same as in Example 1.

[0110] Example 6

[0111] The only difference between this embodiment and Embodiment 1 is that:

[0112] S20, 1mg of 2 (9H carbazole 9 Dissolve acetic acid in 1 mL of anhydrous ethanol and stir thoroughly to obtain a self-assembled monomolecule solution with a concentration of 1 g / L.

[0113] S21. A self-assembled monomolecular solution is coated onto the surface of the first hole transport layer after treatment in S12 by spin coating. Specifically, 50 μL of the above self-assembled monomolecular solution is added dropwise, the spin coating speed is 4000 rpm, the spin coating time is 30 s, and annealing is performed at 100℃ for 10 minutes to obtain an organic self-assembled monolayer (SAM). The first hole transport layer and the organic self-assembled monolayer together form the hole transport layer.

[0114] The remaining operations and settings are consistent with those in Example 1.

[0115] Example 7

[0116] The only difference between this embodiment and Embodiment 1 is that:

[0117] S21. A self-assembled monomolecular solution is coated onto the surface of the first hole transport layer after treatment in S12 by spin coating. Specifically, 50 μL of the self-assembled monomolecular solution is added dropwise, the spin coating speed is 4000 rpm, the spin coating time is 30 s, and then annealing is performed at 100°C for 5 minutes to obtain an organic self-assembled monolayer (SAM). The first hole transport layer and the organic self-assembled monolayer together form the hole transport layer.

[0118] The remaining operations and settings are consistent with those in Example 1.

[0119] Example 8

[0120] The only difference between this embodiment and Embodiment 1 is that:

[0121] S21. A self-assembled monomolecular solution is coated onto the surface of the first hole transport layer after treatment in S12 by spin coating. Specifically, 50 μL of the self-assembled monomolecular solution is added dropwise, the spin coating speed is 4000 rpm, the spin coating time is 30 s, and then annealing is performed at 100℃ for 30 min to obtain an organic self-assembled monolayer (SAM). The first hole transport layer and the organic self-assembled monolayer together form the hole transport layer.

[0122] The remaining operations and settings are consistent with those in Example 1.

[0123] Comparative Example 1

[0124] The only difference between this comparative example and Example 1 is that the functionalized group is a hydroxyl group. Specifically:

[0125] S12. Using water vapor and argon (Ar) as a mixed gas source, the surface of the first hole transport layer (i.e., the annealed nickel oxide layer) is subjected to low-temperature plasma treatment. During the low-temperature plasma treatment, the volumetric flow rate of water vapor is 30 mL / min, the volumetric flow rate of Ar is 10 mL / min, the initial temperature of the low-temperature plasma treatment is room temperature (25℃), the pressure range is 0.1-10 Pa, the power is 50 W, and the duration is 10 min, to obtain a nickel oxide layer with hydroxyl-rich surface.

[0126] The remaining operations and settings are consistent with those in Example 1.

[0127] Comparative Example 2

[0128] The only difference between this comparative example and Example 1 is that the functionalized group is amino, specifically:

[0129] S12. Using NH3 and argon (Ar) as a mixed gas source, the surface of the first hole transport layer (i.e., the annealed nickel oxide layer) is subjected to low-temperature plasma treatment. During the low-temperature plasma treatment, the volumetric flow rate of NH3 is 30 mL / min, the volumetric flow rate of Ar is 10 mL / min, the initial temperature of the low-temperature plasma treatment is room temperature (25℃), the pressure range is 0.1-10 Pa, the power is 50 W, and the duration is 10 min, to obtain an amino-rich nickel oxide layer on the surface.

[0130] The remaining operations and settings are consistent with those in Example 1.

[0131] Comparative Example 3

[0132] The only difference between this comparative example and Example 4 is that the functionalized group is a hydroxyl group. Specifically:

[0133] After obtaining the transparent conductive layer according to step S10, step S11 is not performed.

[0134] S12. Using water vapor and argon (Ar) as a mixed gas source, the surface of the ITO transparent conductive layer is subjected to low-temperature plasma treatment. During the low-temperature plasma treatment, the volumetric flow rate of water vapor is 30 mL / min, the volumetric flow rate of Ar is 10 mL / min, the initial temperature of the low-temperature plasma treatment is room temperature (25℃), the pressure range is 0.1-10 Pa, the power is 50 W, and the duration is 10 min, to obtain an ITO transparent conductive layer with hydroxyl-rich surface.

[0135] The remaining operations and settings are consistent with those in Example 1; in this example, the organic self-assembled monolayer is used as the hole transport layer.

[0136] Comparative Example 4

[0137] The only difference between this comparative example and Example 1 is that the first hole transport layer is not subjected to low-temperature plasma treatment. Specifically:

[0138] After obtaining a clean ITO transparent conductive layer according to operation S10,

[0139] S11. A nickel oxide (NiOx) layer with a thickness of 20 nm was prepared on the ITO transparent conductive layer by magnetron sputtering, and then annealed at a temperature of 150 °C for 15 min to obtain the first hole transport layer.

[0140] S20, 1mg of [2] (9H carbazole 9 [2PACz]ethylphosphonic acid (2PACz) was dissolved in 1 mL of anhydrous ethanol and stirred thoroughly to obtain a self-assembled monomolecular solution with a concentration of 1 g / L.

[0141] S21. A self-assembled monomolecular solution is coated on the surface of the first hole transport layer by spin coating, the specific operation being the same as in Example 1, to obtain an organic self-assembled monomolecular layer (SAM). The first hole transport layer and the organic self-assembled monomolecular layer together form the hole transport layer.

[0142] Subsequent operations and settings remain the same as in Example 1.

[0143] Comparative Example 5

[0144] The only difference between this comparative example and Example 4 is that after obtaining the clean ITO transparent conductive layer according to operation S10, the transparent conductive layer is not subjected to low-temperature plasma treatment. Specifically:

[0145] S20, 1mg of [2] (9H carbazole 9 [2PACz]ethylphosphonic acid (2PACz) was dissolved in 1 mL of anhydrous ethanol and stirred thoroughly to obtain a self-assembled monomolecular solution with a concentration of 1 g / L.

[0146] S21. A self-assembled monomolecular solution is coated on the surface of the ITO transparent conductive layer obtained in S10 by spin coating. Specifically, 50 μL of the above self-assembled monomolecular solution is added dropwise, and spin coating is performed at 4000 rpm for 30 s. Then, annealing is performed at 100°C for 10 minutes to form an organic self-assembled monomolecular layer, which serves as a hole transport layer.

[0147] Subsequent operations and settings remain the same as in Example 4.

[0148] [Testing Method]

[0149] At a light intensity of 100 mW / cm 2 Under AM 1.5G simulated sunlight irradiation, the photovoltaic performance of the perovskite solar cells obtained in the above embodiments and comparative examples was tested, and the current density-voltage (JV) characteristic curves were obtained.

[0150] The values ​​of open-circuit voltage, short-circuit current density, and fill factor can be obtained from the current density-voltage (JV) characteristic curve. The value corresponding to the intersection of the JV curve and the horizontal axis is the open-circuit voltage (V). OC The unit is V; the value corresponding to the intersection of the JV curve and the vertical axis of the coordinate axis is the short-circuit current density (J). SC (Unit: mA / cm) 2 The point on the JV curve corresponding to the perovskite solar cell having the maximum power is P. max (V) max J max The fill factor (FF) can be calculated as follows: FF = (V max ·J max ) / ( V OC ·J SC Photovoltaic conversion efficiency (PCE) refers to the efficiency with which a perovskite solar cell converts solar energy into electrical energy. It can be calculated as follows: PCE = (V0 / V0)2 OC ·J SC ·FF) / P in , where P in The irradiance under simulated AM 1.5G sunlight is 100 mW / cm². 2 .

[0151] The test results are shown in Table 1.

[0152] Table 1

[0153]

[0154] As shown in Table 1, in the perovskite solar cells of Examples 1 to 8, regardless of whether the metal oxide layer is a transparent conductive layer or a first hole transport layer (i.e., a part of the hole transport layer), the surface of the metal oxide layer was treated with low-temperature plasma before the organic self-assembled monolayer was deposited, which effectively improved the anchoring stability and distribution uniformity of the organic self-assembled monolayer and optimized the interfacial contact. Compared with Comparative Examples 4 and 5, which directly prepared the organic self-assembled monolayer without low-temperature plasma treatment, the perovskite solar cells prepared in each example all achieved significantly improved photoelectric conversion efficiency and generally increased fill factor.

[0155] Further detailed analysis reveals that the difference between Examples 1-3 and Comparative Examples 1 and 2 lies solely in the method of low-temperature plasma treatment of the first hole transport layer, resulting in differences in the surface state of the first hole transport layer. The surface of the first hole transport layer in Examples 1-3 contains both hydroxyl and amino groups, while the surface of the first hole transport layer in Comparative Example 1 contains only hydroxyl groups, and the surface of the first hole transport layer in Comparative Example 2 contains only amino groups. Based on the performance parameters, compared to cases where the first hole transport layer surface contains only hydroxyl or amino groups, the simultaneous presence of hydroxyl and amino groups in the surface of the first hole transport layer in Examples 1-3 provides more anchoring points for the SAM while effectively passivating surface defects. This results in a simultaneous improvement in the density and uniformity of the SAM distribution on the surface of the first hole transport layer, leading to a higher short-circuit current density, a higher fill factor, and better conversion efficiency in the perovskite solar cell.

[0156] Similarly, the only difference between Examples 4-5 and Comparative Example 3 is the composition of the plasma source used for the low-temperature plasma treatment of the transparent conductive layer. As a result, the functionalized groups on the surface of the ITO transparent conductive layer obtained in Comparative Example 3 only contain hydroxyl groups. Compared to Comparative Example 3, the surface of the ITO transparent conductive layer in Examples 4-5 includes both hydroxyl and amino groups, leading to significant improvements in the fill factor and conversion efficiency of the perovskite solar cell.

[0157] It is evident that the low-temperature plasma treatment process, which enriches the surface of the metal oxide layer with both hydroxyl and amino groups, optimizes the interfacial contact between the hole transport layer and the perovskite layer, reduces the interface defect state density, suppresses nonradiative recombination of charge carriers, and lowers leakage current. The underlying mechanism may be twofold: firstly, the amino groups effectively passivate surface defects in the metal oxide layer and enhance its hydrophilicity, thus improving the dispersion and adhesion stability of hydroxyl groups on the metal oxide layer surface; secondly, the bonding of hydroxyl groups with the anchoring groups of the self-assembled monomolecule provides more anchoring sites for the SAM, thereby improving the anchoring strength and uniformity of the SAM.

[0158] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for fabricating a perovskite solar cell, the perovskite solar cell comprising a substrate and, sequentially stacked on the substrate, a transparent conductive layer, a first carrier transport layer, a perovskite layer, a second carrier transport layer, and electrodes, characterized in that, The method for preparing the first carrier transport layer includes: Step S1: The surface of the metal oxide layer is modified using a low-temperature plasma process. The modified surface of the metal oxide layer includes functional groups, including hydroxyl and amino groups. Step S2: An organic self-assembled monolayer is prepared on the modified surface of the metal oxide layer to obtain the first carrier transport layer; Wherein, the transparent conductive layer includes the metal oxide layer, and the first carrier transport layer includes the organic self-assembled monolayer; or, the first carrier transport layer includes the metal oxide layer and the organic self-assembled monolayer, and the metal oxide layer is disposed between the transparent conductive layer and the organic self-assembled monolayer.

2. The preparation method according to claim 1, characterized in that, The plasma source used in the low-temperature plasma process includes at least water vapor and NH3.

3. The preparation method according to claim 2, characterized in that, The volumetric flow rate ratio of water vapor to NH3 in the plasma gas source is 3:1 to 1:

1.

4. The preparation method according to claim 1, characterized in that, Before performing step S1, the method for preparing the first carrier transport layer further includes: depositing a liquid film on the surface of the metal oxide layer, wherein the liquid film includes an aqueous film or an ammonia film; optionally, when preparing the liquid film, the amount of liquid applied per unit area of ​​the metal oxide layer is 10 μL / cm. 2 -50μL / cm 2 Preferably 19 μL / cm 2 -25μL / cm 2 .

5. The preparation method according to claim 4, characterized in that, In the case where the liquid film is a water film, the plasma gas source used in the low-temperature plasma process includes at least NH3; optionally, the volumetric flow rate of NH3 in the plasma gas source is 1 mL / min - 100 mL / min, and / or, the plasma gas source used in the low-temperature plasma process also includes at least one of rare gas and oxygen. When the liquid film is an ammonia film, the plasma gas source used in the low-temperature plasma process includes at least one of water vapor, NH3, rare gas or oxygen; optionally, the volumetric flow rate of the plasma gas source is 1 mL / min - 100 mL / min.

6. The preparation method according to any one of claims 1 to 5, characterized in that, The low-temperature plasma process also includes one or more of the following process parameters: working power of 10W-100W, working temperature of 20℃-30℃, working pressure of 0.1Pa-100Pa, and working time of 1min-30min.

7. The preparation method according to any one of claims 1 to 5, characterized in that, In the case where the transparent conductive layer includes the metal oxide layer, the metal oxide layer of the transparent conductive layer includes one or more of indium tin oxide, fluorine-doped tin oxide, zinc tin oxide, zinc-doped indium oxide, or tungsten-doped indium oxide; In cases where the first carrier transport layer comprises the metal oxide layer and the organic self-assembled monolayer, the first carrier transport layer is a hole transport layer, and the metal oxide layer of the first carrier transport layer comprises one or more of nickel oxide, copper oxide, molybdenum oxide, vanadium oxide, tungsten oxide, or iridium oxide; or, if the first carrier transport layer is an electron transport layer, then the metal oxide layer of the first carrier transport layer comprises one or more of titanium dioxide, zinc oxide, or tin oxide.

8. The preparation method according to any one of claims 1 to 5, characterized in that, In the case where the first carrier transport layer includes the metal oxide layer and the organic self-assembled monolayer, the metal oxide layer included in the first carrier transport layer is an annealed metal oxide layer; optionally, the annealing temperature is 100℃-500℃, and the annealing time is 5 min-60 min.

9. The preparation method according to any one of claims 1 to 5, characterized in that, The process of step S2 includes: coating the self-assembled monomolecular material solution onto the modified surface of the metal oxide and then performing an annealing treatment; optionally, the annealing treatment temperature is 60℃-150℃ and the time is 5min-30min, more preferably, the annealing treatment temperature is 80℃-120℃ and the time is 5min-20min.

10. A perovskite solar cell obtained by the preparation method according to any one of claims 1 to 9.

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