Composite interface modification layer and preparation method thereof, and trans-perovskite solar cell

Abstract

The present application relates to a kind of composite interface modification layer and its preparation method, trans perovskite solar cell, the composite interface modification layer includes self-assembled monolayer and passivation layer, self-assembled monolayer is arranged in the surface of hole transport layer in trans perovskite solar cell, passivation layer is arranged on the surface of the self-assembled monolayer;Passivation layer includes passivation agent, passivation agent includes small molecule containing polar functional group, and at least one polar functional group is coupled on hole transport layer.The present application first uses the self-assembled monolayer with larger steric hindrance to carry out the surface modification of hole transport layer, then set passivation layer, layer includes passivation agent, which includes small molecule material containing polar functional group, using the advantage of smaller steric hindrance of itself, squeeze into the gap formed by the self-assembled monolayer with larger steric hindrance, coupled on the hole transport layer, can further passivate hole transport layer surface defect, realize the complete passivation of hole transport layer surface defect.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, and in particular to a composite interface modification layer and its preparation method, and an inverted perovskite solar cell. Background Technology

[0002] The steady-state efficiency of perovskite solar cells has reached 26.81%, and their commercialization is becoming increasingly clear. However, in perovskite solar cells, the surface of the hole transport layer (e.g., NiO) remains a challenge. x Defects in materials such as poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) can cause interfacial reactions with the perovskite light-absorbing layer, such as NiO. x High-valence nickel defects in thin films can oxidize iodide ions in perovskite materials to elemental iodine. Furthermore, nickel oxide films contain many hydroxyl defects, which can decompose perovskite materials and affect carrier transport. Additionally, amino or aryl groups in poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine) may react with halogens or methylammonium ions in perovskite, leading to changes in the crystal structure of perovskite.

[0003] Current research indicates that using self-assembled monolayers (SAMs) can effectively passivate surface defects in the hole transport layer, preventing the perovskite material from being disintegrated and thus improving the photoelectric conversion efficiency of perovskite devices. However, the spatial structure of self-assembled monolayers is relatively complex and has large steric hindrance, making it impossible to completely passivate surface defects in the hole transport layer. They can only partially passivate surface defects. Therefore, how to further achieve complete passivation of the hole transport layer to further improve the overall performance of perovskite solar cells is the current research focus.

[0004] CN118139431A discloses a composite hole transport layer, its fabrication method, and an inversion perovskite solar cell. The composite hole transport layer includes a nickel oxide hole transport layer and at least two passivation layers deposited on the nickel oxide hole transport layer. The passivation layers include a self-assembled monolayer and an alkali metal compound layer. The self-assembled monolayer forms a dense film structure on the nickel oxide hole transport layer, enhancing its passivation function and improving the hole transport efficiency. Simultaneously, the alkali metal compound passivates point defects in the perovskite, improving the interfacial carrier transport capability. While this technology can partially improve the photoelectric conversion efficiency of the device, the introduced alkali metal ions may occupy positions in the perovskite lattice that are unfavorable to carrier transport, or interact strongly with carriers, potentially interfering with carrier transport paths and resulting in a limited improvement in carrier mobility.

[0005] Therefore, based on the existing self-assembled monolayer SAM, how to further improve the passivation effect of the hole transport layer, so as to form a good interfacial contact between it and the perovskite light-absorbing layer, and thus achieve a further significant improvement in the performance of perovskite solar cells, has become an urgent technical problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a composite interface modification layer, its preparation method, and an inverted perovskite solar cell. The composite interface modification layer of this invention comprises a self-assembled monolayer and a passivation layer. First, a self-assembled monolayer with significant steric hindrance is used for surface modification. Then, a passivation layer is formed, containing a passivating agent comprising small molecules with polar functional groups. Taking advantage of its relatively low steric hindrance, the passivating agent "squeezes" into the gaps formed by the sterically hindrance-rich self-assembled monolayer, coupling to the hole transport layer. This further passivates remaining defects on the surface of the hole transport layer. By utilizing the difference in steric hindrance between the two layer structures, complete passivation of surface defects in the hole transport layer is achieved, promoting good interfacial contact between the hole transport layer and the perovskite light-absorbing layer, thereby improving the overall photoelectric performance of the perovskite solar cell.

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

[0008] In a first aspect, the present invention provides a composite interface modification layer, the composite interface modification layer comprising a self-assembled monolayer and a passivation layer, wherein the self-assembled monolayer is disposed on the surface of the hole transport layer in an inverted perovskite solar cell, and the passivation layer is disposed on the surface of the self-assembled monolayer.

[0009] The passivation layer includes a passivating agent, which comprises a small molecule containing a polar functional group, and at least one of the polar functional groups is coupled to the hole transport layer.

[0010] It should be noted that the term "small molecule" in this invention refers to molecules with a molecular weight of less than 500, and the term "coupling" in this invention includes bonding or electrostatic adsorption.

[0011] This invention first deposits a self-assembled monolayer on the surface of the hole transport layer to passivate surface defects. However, due to the complex spatial structure of the self-assembled monolayer, which includes anchoring groups, connecting units, and terminal groups, the overall steric hindrance is relatively large, limiting its effectiveness in passivating surface defects. This invention then deposits a passivation layer containing a passivating agent, which includes small molecules with polar functional groups. Taking advantage of its low steric hindrance, this agent "squeezes" into the gaps formed by the sterically hindrance-laden self-assembled monolayer. Through bonding or electrostatic adsorption, the polar functional groups are coupled to the hole transport layer, further achieving complete passivation of the remaining surface defects. This prevents the defects from combining with the perovskite light-absorbing layer, thereby further improving the overall photoelectric performance of the perovskite solar cell, especially significantly improving the photoelectric conversion efficiency.

[0012] As a preferred embodiment of the present invention, the polar functional group includes any one or a combination of two of the following: amino, nitrogen-containing heterocycle, sulfur-containing heterocycle, oxygen-containing heterocycle, hydroxyl or carboxyl group.

[0013] In this invention, amino groups can interact with defect sites on the surface of the hole transport layer via electrostatic interaction or form hydrogen bonds to achieve passivation. Nitrogen-containing heterocycles, sulfur-containing heterocycles, oxygen-containing heterocycles, hydroxyl groups, or carboxyl groups can all coordinate with oxygen vacancies or uncoordinated metal ions on the surface of the hole transport layer to achieve passivation.

[0014] Preferably, in the small molecule containing polar functional groups, the number of types of polar functional groups is x, where 0 < x ≤ 2, for example, 1 or 2.

[0015] Preferably, in the small molecule containing polar functional groups, the number of polar functional groups is y, where 0 < y ≤ 5, for example, 1, 2, 3, 4 or 5.

[0016] The present invention has x types of polar functional groups, 0 < x ≤ 2, and y types of polar functional groups, 0 < y ≤ 5. This allows the passivating agent to have less steric hindrance, enabling it to smoothly enter the gaps formed by the self-assembled monolayer. The polar functional groups then couple to the hole transport layer and combine with the defects on the surface of the hole transport layer, thereby achieving a better passivation effect.

[0017] Preferably, the passivating agent further includes unsubstituted C1-C3 straight-chain alkyl groups, such as C1, C2, or C3.

[0018] Preferably, the passivating agent comprises any one or a combination of at least two of the following: methylamine, dimethylamine, trimethylamine, ethylenediamine, propylenediamine, 1-methylpyridine iodide, N-ethylpyridine iodide, N-ethyl-3-methylpyridine iodide, 2-aminopyridine, 3-iodopyrrole, glycine, alanine, oxazole-2-carboxylic acid, 4-[1,3-dihydroxy-2-hydroxymethylpropane]-1-methylpyridine iodide, or 3-hydroxy-3-methylpyrrole hydrochloride.

[0019] As a preferred embodiment of the present invention, the material of the hole transport layer includes NiO. x Or poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine).

[0020] Preferably, the thickness of the hole transport layer is 10nm-50nm, such as 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm or 50nm.

[0021] Preferably, the thickness of the self-assembled monolayer is 0.5nm-5nm, such as 0.5nm, 1nm, 1.5nm, 2nm, 2.5nm, 3nm, 3.5nm, 4nm, 4.5nm or 5nm.

[0022] Preferably, the thickness of the passivation layer is 0.5nm-10nm, such as 0.5nm, 2nm, 4nm, 6nm, 8nm or 10nm.

[0023] As a preferred embodiment of the present invention, the self-assembled monolayer includes a self-assembled monomolecule material, which includes 4-(7H-dibenzo[c,g]carbazole-7-yl)phosphoric acid (4PADCB), (2-(9H-carbazole-9-yl)ethyl)phosphoric acid (2PACz), (2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid (Me-2PACZ), and (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO). MeO-PhPACz), [2-(7H-dibenzocarbazole-7-yl)ethyl]phosphoric acid (Ph-2PACZ), ((4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)phosphoric acid (MeO-PhPACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACZ), or [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACZ) or any one or a combination of at least two of these.

[0024] In a second aspect, the present invention also provides a method for preparing a composite interface modification layer according to the first aspect, the method comprising the following steps:

[0025] In an inverted perovskite solar cell, a self-assembled monolayer is first prepared on the surface of the hole transport layer, and then a passivation layer is prepared on the surface of the self-assembled monolayer to obtain a composite interface modification layer.

[0026] As a preferred technical solution of the present invention, the method for preparing the self-assembled monolayer includes: mixing the self-assembled monomolecule material with a first solvent to obtain a self-assembled monomolecule solution, coating the self-assembled monomolecule solution onto the surface of the hole transport layer in an inverted perovskite solar cell to obtain a first liquid film, and obtaining the self-assembled monolayer after a first annealing.

[0027] Preferably, in the self-assembled monomolecular solution, the concentration of the self-assembled monomolecular material is 0.1 mg / mL to 5 mg / mL, for example, 0.1 mg / mL, 0.5 mg / mL, 1.0 mg / mL, 1.5 mg / mL, 2.0 mg / mL, 2.5 mg / mL, 3.0 mg / mL, 3.5 mg / mL, 4.0 mg / mL, 4.5 mg / mL, or 5.0 mg / mL.

[0028] Preferably, in the self-assembled monomolecular solution, the first solvent includes any one or a combination of at least two of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or isopropanol (IPA).

[0029] Preferably, the coating amount of the self-assembled monomolecular solution is 0.4 μL / cm. 2 -2μL / cm 2 For example, 0.4 μL / cm 2 0.5 μL / cm 2 0.6 μL / cm 2 0.7 μL / cm 2 0.8 μL / cm 2 0.9μL / cm 2 1μL / cm 2 1.1 μL / cm 2 1.2 μL / cm 2 1.3 μL / cm 2 1.4 μL / cm 2 1.5 μL / cm 2 1.6 μL / cm 2 1.7 μL / cm 2 1.8 μL / cm 2 1.9 μL / cm 2 or 2μL / cm 2 wait.

[0030] Preferably, the temperature of the first annealing is 80℃-120℃, such as 80℃, 90℃, 100℃, 110℃ or 120℃.

[0031] Preferably, the first annealing time is 5 min to 15 min, such as 5 min, 8 min, 10 min, 12 min or 15 min.

[0032] Preferably, after the first annealing, the process further includes a step of surface rinsing of the film to obtain a self-assembled monolayer.

[0033] In this invention, the film after the first annealing is rinsed to remove the self-assembled monolayer material that has not chemically bonded to the hole transport layer, thereby exposing the unpassivated defects as much as possible. This makes it easier for the polar functional groups in the passivating agent to couple to the hole transport layer, and thus completely passivate the surface defects.

[0034] As a preferred technical solution of the present invention, the method for preparing the passivation layer includes: mixing the passivating agent material with a second solvent uniformly to obtain a passivation liquid, coating the passivation liquid onto the surface of the self-assembled monolayer to obtain a second liquid film, and obtaining the passivation layer after a second annealing.

[0035] Preferably, the passivating agent material in the passivation solution includes any one or a combination of at least two of the following: methylamine solution, dimethylamine solution, trimethylamine solution, ethylenediamine, propylenediamine, 1-methylpyridine iodide, N-ethylpyridine iodide, N-ethyl-3-methylpyridine iodide, 2-aminopyridine, 3-iodopyrrole, glycine, alanine, oxazole-2-carboxylic acid, 4-[1,3-dihydroxy-2-hydroxymethylpropane]-1-methylpyridine iodide, or 3-hydroxy-3-methylpyrrole hydrochloride.

[0036] It should be noted that the methylamine solution used in this invention is a commercially available 40% methylamine aqueous solution, the dimethylamine solution is a commercially available 40% dimethylamine aqueous solution, and the trimethylamine solution is a commercially available 25% trimethylamine aqueous solution.

[0037] It should be noted that the coating method described in this invention is not subject to specific requirements or special limitations. Any coating method commonly used in the art is applicable to this invention, such as spin coating, blade coating, or slot coating.

[0038] Preferably, the concentration of the passivating agent material in the passivation solution is 0.05 mg / mL to 2.5 mg / mL, such as 0.05 mg / mL, 0.08 mg / mL, 0.1 mg / mL, 0.3 mg / mL, 0.5 mg / mL, 0.8 mg / mL, 1.0 mg / mL, 1.3 mg / mL, 1.5 mg / mL, 1.8 mg / mL, 2.0 mg / mL, 2.3 mg / mL, or 2.5 mg / mL.

[0039] In this invention, controlling the concentration of the passivating agent material to be between 0.05 mg / mL and 2.5 mg / mL allows for complete passivation of defects in the hole transport layer. The passivating agent material can be more uniformly dispersed on the self-assembled monolayer and fully penetrate the gaps between the self-assembled monolayers, reducing non-radiative recombination, increasing the open-circuit voltage and fill factor, and thus improving the photoelectric conversion efficiency of the battery to achieve the best passivation effect. If the concentration of the passivating agent material is too high, it will be difficult to disperse, resulting in more small molecules remaining on the surface of the self-assembled monolayer, affecting charge transport, and thus causing a decrease in short-circuit current density and fill factor, affecting the photoelectric conversion efficiency of the battery. If the concentration of the passivating agent material is too low, it will not be sufficient to completely passivate the surface defects of the hole transport layer, resulting in only a slight improvement in short-circuit current density, open-circuit voltage, and fill factor.

[0040] Preferably, in the passivation solution, the second solvent includes any one or a combination of at least two of methanol, ethanol, or isopropanol.

[0041] Preferably, the coating amount of the passivation solution is 0.6 μL / cm. 2 -2uL / cm 2 For example, 0.6 μL / cm 2 0.7 μL / cm 2 0.8 μL / cm 2 0.9μL / cm 2 1μL / cm 2 1.1 μL / cm 2 1.2 μL / cm 2 1.3 μL / cm 2 1.4 μL / cm 2 1.5 μL / cm 2 1.6 μL / cm 2 1.7 μL / cm 2 1.8 μL / cm 2 1.9 μL / cm 2 or 2μL / cm 2 wait.

[0042] Preferably, the temperature of the second annealing is 70℃-130℃, such as 70℃, 80℃, 90℃, 100℃, 110℃, 120℃ or 130℃.

[0043] Preferably, the second annealing time is 5 min to 20 min, such as 5 min, 10 min, 15 min or 20 min.

[0044] It should be noted that the coating method described in this invention is not subject to specific requirements or special limitations. Any coating method commonly used in the art is applicable to this invention, such as spin coating, blade coating, or slot coating.

[0045] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0046] The self-assembled monomolecule material is mixed uniformly with the first solvent to obtain a self-assembled monomolecule solution. The self-assembled monomolecule solution is then coated on the surface of the hole transport layer in an inverted perovskite solar cell to obtain a first liquid film. After a first annealing at 80℃-120℃ for 5min-15min, the self-assembled monomolecule layer is obtained.

[0047] In the self-assembled monomolecular solution, the concentration of the self-assembled monomolecular material is 0.1 mg / mL-5 mg / mL; the coating amount of the self-assembled monomolecular solution is 0.4 μL / cm². 2 -2μL / cm 2 ;

[0048] The passivating agent material is mixed evenly with the second solvent to obtain a passivating liquid. The passivating liquid is then coated on the surface of the self-assembled monolayer to obtain a second liquid film. After a second annealing at 70℃-130℃ for 5min-20min, a composite interface modification layer is obtained.

[0049] In the passivation solution, the concentration of the passivating agent material is 0.05 mg / mL to 2.5 mg / mL; the coating amount of the passivation solution is 0.6 μL / cm. 2 -2μL / cm 2 .

[0050] Thirdly, the present invention also provides an inverted perovskite solar cell, wherein the inverted perovskite solar cell includes a composite interface modification layer as described in the first aspect, or a composite interface modification layer prepared by the preparation method described in the second aspect.

[0051] As a preferred technical solution of the present invention, the inverted perovskite solar cell comprises, from bottom to top, a conductive substrate layer, a hole transport layer, a composite interface modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode stacked together.

[0052] Preferably, the composite interface modification layer comprises, from bottom to top, a self-assembled monolayer and a passivation layer stacked together.

[0053] Preferably, in the perovskite light-absorbing layer, the perovskite material has the structural formula ABX3, wherein A includes any one or a combination of at least two of cesium ions, rubidium ions, methylamino groups or formamidinium groups, B includes lead ions and / or tin ions, and X includes any one or a combination of at least two of bromide ions, iodide ions or chloride ions.

[0054] It should be noted that the method for preparing the inverted perovskite solar cell described in this invention is existing technology, and those skilled in the art can make adaptive selections and adjustments according to actual conditions.

[0055] By way of example, the present invention provides a method for fabricating an inverted perovskite solar cell, the method comprising the following steps:

[0056] 1) Provide an FTO conductive substrate layer;

[0057] 2) A hole transport layer with a thickness of 20nm-60nm is prepared on the FTO conductive substrate;

[0058] The present invention does not impose specific requirements or special limitations on the preparation method of the hole transport layer. Any method commonly used in the art is applicable to the present invention, such as magnetron sputtering, spin coating, blade coating, vapor deposition or slot coating, etc.

[0059] 3) A composite interface modification layer is prepared on the hole transport layer;

[0060] 4) A perovskite light-absorbing layer with a thickness of 400 nm-1000 nm is prepared on the composite interface modification layer;

[0061] In this invention, no specific requirements or special limitations are imposed on the preparation method of the perovskite light-absorbing layer. Any method commonly used in the art is applicable to this invention, such as spin coating, slot coating, inkjet printing, vacuum thermal deposition, electron beam evaporation, magnetron sputtering, or atomic layer deposition.

[0062] 5) An electron transport layer with a thickness of 10 nm-50 nm is prepared on the perovskite light-absorbing layer;

[0063] In this invention, no specific requirements or limitations are placed on the type of material used for the electron transport layer. Any material commonly used in the art is applicable to this invention, such as C. 60 Or PCBM, etc.;

[0064] The method for preparing the electron transport layer is not specifically required or limited in this invention. Any method commonly used in the art is applicable to this invention, such as thermal evaporation.

[0065] 6) Fabricate a metal electrode with a thickness of 60nm-120nm on the electron transport layer;

[0066] In this invention, there are no specific requirements or special limitations on the type of material of the metal electrode. Any type commonly used in the art is applicable to this invention, such as Ag, Cu, Au or Bi.

[0067] The present invention does not impose specific requirements or special limitations on the preparation method of the metal electrode. Any method commonly used in the art is applicable to the present invention, such as thermal evaporation.

[0068] Compared with the prior art, the present invention has at least the following beneficial effects:

[0069] 1) This invention employs a composite interface modification layer to passivate the surface of the hole transport layer. First, a self-assembled monolayer with significant steric hindrance is used for surface modification, which can partially passivate defects on the surface of the hole transport layer. Then, a passivation layer is set, which includes a passivating agent. This passivating agent includes small molecule materials containing polar functional groups. Taking advantage of its small steric hindrance, it "squeezes" into the gaps formed by the self-assembled monolayer with significant steric hindrance and couples to the hole transport layer. This can further passivate the remaining defects on the surface of the hole transport layer and prevent the defects on the surface of the hole transport layer from combining with the perovskite light-absorbing layer, thereby further improving the overall photoelectric performance of the inverted perovskite solar cell, especially significantly improving the photoelectric conversion efficiency.

[0070] 2) The passivating agent of the present invention includes a small molecule material containing polar functional groups. The passivating agent has small steric hindrance and can smoothly enter the gaps formed by the self-assembled monolayer. It utilizes the polar functional groups to couple onto the hole transport layer and combine with the remaining defects on the surface of the hole transport layer, thereby achieving the passivation effect.

[0071] 3) The inverted perovskite solar cell prepared using the composite interface modification layer provided by this invention exhibits a short-circuit current density of 23.99-24.69 mA / cm². 2 The open-circuit voltage is between 1.02V and 1.06V, the photoelectric conversion efficiency is between 17.01% and 19.35%, the fill factor is between 68.51% and 75.27%, and the series resistance is below 8.94 ohms, and can be as low as 5.50 ohms. Detailed Implementation

[0072] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0073] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0074] Example 1

[0075] This embodiment provides a composite interface modification layer and its preparation method. The composite interface modification layer includes a 4PADCB layer and a methylamine layer. The 4PADCB layer is disposed in NiO in an inverted perovskite solar cell. x The methylamine layer is disposed on the surface of the 4PADCB layer, and the amino groups in the methylamine are coupled to NiO. x On the hole transport layer;

[0076] The preparation method includes the following steps:

[0077] 4PADCB material and DMF were mixed evenly to obtain a self-assembled monomolecular solution with a concentration of 0.5 mg / mL of 4PADCB material. 40% methylamine aqueous solution and ethanol were mixed evenly to obtain a passivation solution with a concentration of 0.1 mg / mL of 40% methylamine aqueous solution.

[0078] 25 μL of self-assembled unimolecular solution (coating amount 1 μL / cm) 2 Scraping onto NiO x Hole transport layer (NiO) x The hole transport layer is located on the surface of a 5cm × 5cm FTO conductive substrate. It is then annealed on a heating table at 100℃ for 10 minutes. After cooling to room temperature, the surface is rinsed with DMF solvent and dried completely. Finally, 25μL of passivation solution (coating amount 1μL / cm) is applied. 2 The entire material was placed on a heating table at 100℃ and heated for 10 minutes, then cooled to room temperature to obtain a composite interface modification layer.

[0079] Example 2

[0080] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Example 1 is that the concentration of 40% methylamine aqueous solution in the passivation solution is 0.2 mg / mL in the preparation method, while the rest of the preparation method and parameters are the same as in Example 1.

[0081] Example 3

[0082] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a 1-methylpyridine iodide layer, wherein the 4PADCB layer is disposed in the NiO in the inverted perovskite solar cell. x On the surface of the hole transport layer, the 1-methylpyridine iodide layer is disposed on the surface of the 4PADCB layer, and the pyridine group in the 1-methylpyridine iodide is coupled to NiO. x On the hole transport layer;

[0083] In the preparation method described above, 40% methylamine aqueous solution is replaced with 1-methylpyridine iodide, and the concentration of 1-methylpyridine iodide in the passivation solution is 0.1 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0084] Example 4

[0085] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a glycine layer, wherein the 4PADCB layer is disposed in the NiO in the inverted perovskite solar cell. x On the surface of the hole transport layer, the glycine layer is disposed on the surface of the 4PADCB layer, and the amino and / or carboxyl groups in the glycine are coupled to NiO. x The hole transport layer (in this embodiment, the passivation layer includes multiple glycine molecules, and each glycine molecule has one coupling group. Therefore, the coupling of groups in the passivation layer can be divided into three types: one is that multiple glycine molecules are all coupled to NiO with amino groups.) x On the hole transport layer, secondly, multiple glycine molecules are all coupled with carboxyl groups to NiO. x In the hole transport layer, thirdly, among multiple glycine molecules, some glycine molecules are amino-coupled to NiO. x In the hole transport layer, some glycine molecules are coupled to NiO via carboxylic acid. x (on the hole transport layer);

[0086] In the preparation method described above, 40% methylamine aqueous solution is replaced with glycine, and the concentration of glycine in the passivation solution is 0.1 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0087] Example 5

[0088] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a 3-hydroxy-3-methylpyrrole hydrochloride layer. The 4PADCB layer is disposed in NiO in an inverted perovskite solar cell. xOn the surface of the hole transport layer, the 3-hydroxy-3-methylpyrrole hydrochloride layer is disposed on the surface of the 4PADCB layer, wherein the hydroxyl and / or pyrrole groups in the 3-hydroxy-3-methylpyrrole hydrochloride are coupled to NiO. x On the hole transport layer (same as in Example 4, the coupling of functional groups can be divided into the above three types);

[0089] In the preparation method described above, the 40% methylamine aqueous solution is replaced with 3-hydroxy-3-methylpyrrole hydrochloride, the concentration of 3-hydroxy-3-methylpyrrole hydrochloride in the passivation solution is 0.1 mg / mL, and the remaining preparation methods and parameters are consistent with those in Example 1.

[0090] Example 6

[0091] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Example 1 is that the concentration of 4PADCB material in the self-assembled monomolecule solution is 1 mg / mL in the preparation method, while the rest of the preparation methods and parameters are consistent with Example 1.

[0092] Example 7

[0093] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a Me-4PACz layer and a methylamine layer, wherein the Me-4PACz layer is disposed in the NiO in the inverted perovskite solar cell. x On the surface of the hole transport layer, the methylamine layer is disposed on the surface of the Me-4PACz layer, and the amino groups in the methylamine are coupled to NiO. x On the hole transport layer;

[0094] In the preparation method described above, 4PADCB material is replaced with Me-4PACz material, and the concentration of Me-4PACz material in the self-assembled monomolecule solution is 0.5 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0095] Example 8

[0096] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a 1-methylpyridine iodide layer, wherein the 4PADCB layer is disposed in the NiO in the inverted perovskite solar cell. x On the surface of the hole transport layer, the 1-methylpyridine iodide layer is disposed on the surface of the 4PADCB layer, and the pyridine group in the 1-methylpyridine iodide is coupled to NiO. x On the hole transport layer;

[0097] In the preparation method described above, 40% methylamine aqueous solution is replaced with 1-methylpyridine iodide, and the concentration of 1-methylpyridine iodide in the passivation solution is 0.2 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0098] Example 9

[0099] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Example 1 is that in the preparation method, the concentration of 40% methylamine aqueous solution in the passivation solution is 0.05 mg / mL, and the concentration of 4PADCB material in the self-assembled single molecule solution is 0.1 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0100] Example 10

[0101] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Example 1 is that in the preparation method, the concentration of 40% methylamine aqueous solution in the passivation solution is 2.5 mg / mL, and the concentration of 4PADCB material in the self-assembled single molecule solution is 5 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0102] Example 11

[0103] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a 2-aminopyridine layer, wherein the 4PADCB layer is disposed in the NiO in the inverted perovskite solar cell. x On the surface of the hole transport layer, the 2-aminopyridine layer is disposed on the surface of the 4PADCB layer, wherein the pyridine groups and / or amino groups in the 2-aminopyridine are coupled to NiO. x On the hole transport layer (same as in Example 4, the coupling of functional groups can be divided into the above three types);

[0104] In the preparation method described above, 40% methylamine aqueous solution is replaced with 2-aminopyridine, and the concentration of 2-aminopyridine in the passivation solution is 0.1 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0105] Example 12

[0106] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Example 1 is that the concentration of 40% methylamine aqueous solution in the passivation solution is 3 mg / mL in the preparation method, while the rest of the preparation methods and parameters are the same as in Example 1.

[0107] Example 13

[0108] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the concentration of 40% methylamine aqueous solution in the passivation solution is 0.025 mg / mL in the preparation method, while the rest of the preparation method and parameters are the same as in Embodiment 1.

[0109] Example 14

[0110] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a vinyl methyl ether layer, wherein the 4PADCB layer is disposed in the NiO in the inverted perovskite solar cell. x The surface of the hole transport layer, wherein the vinyl methyl ether layer is disposed on the surface of the 4PADCB layer;

[0111] In the preparation method described above, 40% methylamine aqueous solution is replaced with vinyl methyl ether, the concentration of vinyl methyl ether in the passivation solution is 0.1 mg / mL, and the remaining preparation methods and parameters are consistent with those in Example 1.

[0112] Example 15

[0113] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that, in the preparation method, the coating amount of the passivation solution is 0.6 μL / cm. 2 The remaining preparation methods and parameters are consistent with those in Example 1.

[0114] Example 16

[0115] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that, in the preparation method, the coating amount of the passivation solution is 2 μL / cm. 2 The remaining preparation methods and parameters are consistent with those in Example 1.

[0116] Example 17

[0117] This embodiment provides a composite interface modification layer and its preparation method. The difference between this embodiment and Embodiment 1 is that the composite interface modification layer includes a 4PADCB layer and a D-serine layer, wherein the 4PADCB layer is disposed in NiO in an inverted perovskite solar cell. x The D-serine layer is disposed on the surface of the 4PADCB layer on the surface of the hole transport layer.

[0118] In the preparation method described above, 40% methylamine aqueous solution is replaced with D-serine, and the concentration of D-serine in the passivation solution is 0.1 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0119] Example 18

[0120] This comparative example provides a composite interface modification layer and its preparation method. The difference between this example and Example 1 is that the composite interface modification layer includes a 4PADCB layer and a dibutylamine layer, wherein the 4PADCB layer is disposed in the NiO in the inverted perovskite solar cell. x The dibutylamine layer is disposed on the surface of the 4PADCB layer on the surface of the hole transport layer.

[0121] In the preparation method described above, 40% methylamine aqueous solution is replaced with dibutylamine, and the concentration of dibutylamine in the passivation solution is 0.1 mg / mL. The remaining preparation methods and parameters are consistent with those in Example 1.

[0122] Comparative Example 1

[0123] This comparative example provides an interface modification layer and its preparation method. The difference between this embodiment and Example 1 is that the interface modification layer includes a 4PADCB layer, which is disposed in the NiO in the inverted perovskite solar cell. x Hole transport layer surface;

[0124] In the preparation method described above, the preparation of the methylamine layer is omitted, and the remaining preparation methods and parameters are consistent with those in Example 1.

[0125] Application Example 1

[0126] This application example provides an inverted perovskite solar cell and its fabrication method. The inverted perovskite solar cell sequentially comprises a conductive substrate layer, a hole transport layer, a composite interface modification layer provided in Example 1, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode stacked together.

[0127] The preparation method includes the following steps:

[0128] (1) Prepare an FTO thin film on a 5cm×5cm glass substrate, and then place the above material on a laser operation stage. Draw P1 lines parallel to the side length at intervals of 1cm from any side length. The P1 lines divide the ITO into multiple independent parts and expose the glass substrate to obtain an FTO conductive substrate layer.

[0129] (2) A 15 nm layer of NiO was deposited on a conductive substrate using magnetron sputtering. x Hole transport layer;

[0130] (3) The composite interface modification layer of Example 1 was prepared using the preparation method provided in Example 1;

[0131] (4) A 500 nm thick perovskite light-absorbing layer was prepared on the surface of the composite interface modification layer by a blade coating method. The preparation method of the perovskite precursor solution included: dissolving the precursor material in 1 mL of N,N-dimethylformamide (DMF) to obtain Cs with a concentration of 1.2 mol / L. 0.1 FA 0.9 PbI3;

[0132] (5) A 20 nm layer of C was deposited on the surface of the perovskite light-absorbing layer by thermal evaporation. 60 An electron transport layer is formed, followed by the deposition of an 80 nm Cu electrode using magnetron sputtering or thermal evaporation to obtain an inverted perovskite solar cell.

[0133] Application Example 2-18 and Comparison Application Example 1

[0134] The composite interface modification layers / interface modification layers prepared in Examples 2-18 and Comparative Example 1 were applied to inverted perovskite solar cells. The preparation method and parameters of the inverted perovskite solar cells were consistent with those in Application Example 1. The resulting inverted perovskite solar cells corresponded to Application Examples 2-18 and Comparative Application Example 1, respectively.

[0135] Comparative Application Example 2

[0136] This comparative application example 2 provides an inverted perovskite solar cell and its fabrication method. The inverted perovskite solar cell sequentially comprises a conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode stacked together.

[0137] The difference between the preparation method described above and application example 1 is that step (3) of preparing the composite interface modification layer is omitted, and the NiO... x A perovskite light-absorbing layer was directly prepared on the surface of the hole transport layer, and the remaining preparation methods and parameters were consistent with those in Application Example 1.

[0138] The inverted perovskite solar cells prepared according to Example 1-18 and Comparative Application Example 1-2 were tested for short-circuit current density, open-circuit voltage, photoelectric conversion efficiency, fill factor, and series resistance using an IV meter (model: Guangyan Technology SS-X200R) under a standard light intensity (test area, 1 cm²). 2 The specific test results are shown in Table 1.

[0139] Table 1

[0140]

[0141] The test results show that:

[0142] (1) As can be seen from Examples 1-11 and 15-16, this invention combines a self-assembled monolayer and a passivation layer, utilizing the difference in steric hindrance between the materials in their layer structures to achieve complete passivation of surface defects in the hole transport layer, thereby improving the overall performance of the perovskite solar cell. Specifically, the short-circuit current density of the cell is 23.99-24.69 mA / cm². 2 The open-circuit voltage is between 1.02V and 1.06V, the photoelectric conversion efficiency is between 17.01% and 19.35%, the fill factor is between 68.51% and 75.27%, and the series resistance is below 8.94 ohms, and can be as low as 5.50 ohms.

[0143] (2) As can be seen from Application Example 1 and Application Examples 12-13, the present invention controls the concentration of the passivating agent material to be 0.05 mg / mL-2.5 mg / mL, which can passivate the defects in the hole transport layer. The passivating material can be more uniformly dispersed on the self-assembled monolayer and fully penetrate into the gaps between the self-assembled monolayers, reducing non-radiative recombination, increasing the open circuit voltage and fill factor, and thus improving the battery efficiency to obtain the best passivation effect.

[0144] (3) As can be seen from Application Example 1 and Application Example 14, the polar functional groups used in this invention are more likely to couple onto the hole transport layer and the passivation effect is also better. If vinyl methyl ether is used, for example, in Example 14, the coupling of carbon-carbon double bonds and ether bonds inside is relatively difficult, and the passivation effect is relatively poor.

[0145] (4) As can be seen from Application Examples 1 and 17-18, in the passivating agent structure used in this invention, the number of polar functional groups is x, 0 < x ≤ 2, which makes the passivating agent have small steric hindrance and can smoothly enter the gaps formed by the self-assembled monolayer. The polar functional groups play a role in coupling with the hole transport layer and combining with the defects on the surface of the hole transport layer, thereby achieving a better passivation effect. The control of the unsubstituted C1-C3 straight-chain alkyl group with 1-3 carbon atoms is also to make the passivating agent have small steric hindrance and can smoothly enter the gaps formed by the self-assembled monolayer. If the steric hindrance of the passivating agent is too large, it cannot squeeze into the gaps formed by the self-assembled monolayer and cannot achieve a further passivation effect.

[0146] (5) As can be seen from Application Example 1 and Comparative Application Example 1, if the present invention only uses a self-assembled monolayer without setting a corresponding passivation layer, it cannot achieve complete passivation of the surface defects of the hole transport layer. When used in perovskite solar cells, the short-circuit current density, open-circuit voltage, photoelectric conversion efficiency and fill factor are all reduced, and the series resistance is further increased.

[0147] (6) As can be seen from Application Example 1 and Comparative Application Example 2, if the composite interface modification layer is not used in this invention, there are a lot of defects on the surface of the hole transport layer. When used in perovskite solar cells, the short-circuit current density, open-circuit voltage, photoelectric conversion efficiency and fill factor are significantly reduced, and the series resistance is significantly increased.

[0148] In summary, the composite interface modification layer of this invention comprises a self-assembled monolayer and a passivation layer. First, a self-assembled monolayer with significant steric hindrance is used for surface modification. Then, a passivation layer is formed, containing a passivating agent, which includes small molecule materials with polar functional groups. Taking advantage of its relatively small steric hindrance, the passivating agent "squeezes" into the gaps formed by the self-assembled monolayer with greater steric hindrance, coupling to the hole transport layer. This further passivates the remaining defects on the surface of the hole transport layer. By utilizing the difference in steric hindrance between the materials in the two layer structures, complete passivation of the surface defects of the hole transport layer is achieved, promoting good interfacial contact between the hole transport layer and the perovskite light-absorbing layer, thereby improving the overall photoelectric performance of the perovskite solar cell.

[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. A composite interface modification layer, characterized in that, The composite interface modification layer includes a self-assembled monolayer and a passivation layer. The self-assembled monolayer is disposed on the surface of the hole transport layer in the inverted perovskite solar cell, and the passivation layer is disposed on the surface of the self-assembled monolayer. The passivation layer includes a passivating agent, which comprises a small molecule containing a polar functional group, and at least one of the polar functional groups is coupled to the hole transport layer.

2. The composite interface modification layer according to claim 1, characterized in that, The polar functional group includes any one or a combination of two of the following: amino, nitrogen-containing heterocycle, sulfur-containing heterocycle, oxygen-containing heterocycle, hydroxyl or carboxyl group; Preferably, in the small molecule containing polar functional groups, the number of different types of polar functional groups is x, where 0 < x ≤ 2; Preferably, in the small molecule containing polar functional groups, the number of polar functional groups is y, where 0 < y ≤ 5; Preferably, the passivating agent further includes an unsubstituted C1-C3 straight-chain alkyl group in its structural formula; Preferably, the passivating agent comprises any one or a combination of at least two of the following: methylamine, dimethylamine, trimethylamine, ethylenediamine, propylenediamine, 1-methylpyridine iodide, N-ethylpyridine iodide, N-ethyl-3-methylpyridine iodide, 2-aminopyridine, 3-iodopyrrole, glycine, alanine, oxazole-2-carboxylic acid, 4-[1,3-dihydroxy-2-hydroxymethylpropane]-1-methylpyridine iodide, or 3-hydroxy-3-methylpyrrole hydrochloride.

3. The composite interface modification layer according to claim 1 or 2, characterized in that, The hole transport layer is made of NiO. x Or poly(bis(4-phenyl)(2,4,6-trimethylphenyl)amine); Preferably, the thickness of the hole transport layer is 10nm-50nm; Preferably, the thickness of the self-assembled monolayer is 0.5 nm to 5 nm; Preferably, the thickness of the passivation layer is 0.5 nm to 10 nm.

4. The composite interface modification layer according to any one of claims 1-3, characterized in that, The self-assembled monolayer includes a self-assembled monomolecule material, which includes any one or a combination of at least two of the following: 4-(7H-dibenzo[c,g]carbazole-7-yl)phosphoric acid, (2-(9H-carbazole-9-yl)ethyl)phosphoric acid, (2-(3,6-dimethyl-9H-carbazole-9-yl)ethyl)phosphonic acid, (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid, [2-(7H-dibenzocarbazole-7-yl)ethyl]phosphoric acid, ((4-(3,6-dimethoxy-9H-carbazole-9-yl)phenyl)phosphoric acid, (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid, or [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid.

5. A method for preparing a composite interface modification layer according to any one of claims 1-4, characterized in that, The preparation method includes the following steps: In an inverted perovskite solar cell, a self-assembled monolayer is first prepared on the surface of the hole transport layer, and then a passivation layer is prepared on the surface of the self-assembled monolayer to obtain a composite interface modification layer.

6. The preparation method according to claim 5, characterized in that, The method for preparing the self-assembled monolayer includes: mixing the self-assembled monomolecule material with a first solvent to obtain a self-assembled monomolecule solution; coating the self-assembled monomolecule solution onto the surface of the hole transport layer in an inverted perovskite solar cell to obtain a first liquid film; and after a first annealing, obtaining the self-assembled monolayer. Preferably, in the self-assembled monomolecular solution, the concentration of the self-assembled monomolecular material is 0.1 mg / mL to 5 mg / mL; Preferably, in the self-assembled monomolecular solution, the first solvent includes any one or a combination of at least two of dimethylformamide, dimethyl sulfoxide, or isopropanol; Preferably, the coating amount of the self-assembled monomolecular solution is 0.4 μL / cm. 2 -2μL / cm 2 ; Preferably, the temperature of the first annealing is 80℃-120℃; Preferably, the first annealing time is 5 min to 15 min.

7. The preparation method according to claim 5 or 6, characterized in that, The method for preparing the passivation layer includes: mixing the passivating agent material with a second solvent to obtain a passivation liquid, coating the passivation liquid onto the surface of the self-assembled monolayer to obtain a second liquid film, and then performing a second annealing to obtain the passivation layer. Preferably, in the passivation solution, the passivating agent material includes any one or a combination of at least two of the following: methylamine solution, dimethylamine solution, trimethylamine solution, ethylenediamine, propylenediamine, 1-methylpyridine iodide, N-ethylpyridine iodide, N-ethyl-3-methylpyridine iodide, 2-aminopyridine, 3-iodopyrrole, glycine, alanine, oxazole-2-carboxylic acid, 4-[1,3-dihydroxy-2-hydroxymethylpropane]-1-methylpyridine iodide, or 3-hydroxy-3-methylpyrrole hydrochloride. Preferably, the concentration of the passivating agent material in the passivation solution is 0.05 mg / mL to 2.5 mg / mL; Preferably, in the passivation solution, the second solvent includes any one or a combination of at least two of methanol, ethanol, or isopropanol; Preferably, the coating amount of the passivation solution is 0.6 μL / cm. 2 -2uL / cm 2 ; Preferably, the temperature of the second annealing is 70℃-130℃; Preferably, the second annealing time is 5 min to 20 min.

8. The method for preparing the composite interface modification layer according to claim 5, characterized in that, The preparation method includes the following steps: The self-assembled monomolecule material is mixed uniformly with the first solvent to obtain a self-assembled monomolecule solution. The self-assembled monomolecule solution is then coated on the surface of the hole transport layer in an inverted perovskite solar cell to obtain a first liquid film. After a first annealing at 80℃-120℃ for 5min-15min, the self-assembled monomolecule layer is obtained. In the self-assembled monomolecular solution, the concentration of the self-assembled monomolecular material is 0.1 mg / mL-5 mg / mL; the coating amount of the self-assembled monomolecular solution is 0.4 μL / cm². 2 -2μL / cm 2 ; The passivating agent material is mixed evenly with the second solvent to obtain a passivating liquid. The passivating liquid is then coated on the surface of the self-assembled monolayer to obtain a second liquid film. After a second annealing at 70℃-130℃ for 5min-20min, a composite interface modification layer is obtained. In the passivation solution, the concentration of the passivating agent material is 0.05 mg / mL to 2.5 mg / mL; the coating amount of the passivation solution is 0.6 μL / cm. 2 -2μL / cm 2 .

9. A reverse perovskite solar cell, characterized in that, The inverted perovskite solar cell includes the composite interface modification layer as described in any one of claims 1-4, or the composite interface modification layer prepared by the preparation method as described in any one of claims 5-8.

10. The inverted perovskite solar cell according to claim 9, characterized in that, The inverted perovskite solar cell comprises, from bottom to top, a conductive substrate layer, a hole transport layer, a composite interface modification layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode stacked together. Preferably, the composite interface modification layer comprises, from bottom to top, a self-assembled monolayer and a passivation layer stacked together.

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