A perovskite light-absorbing layer based on a dual synergistic passivation strategy, and a preparation method and application thereof

Abstract

The application relates to a perovskite light-absorbing layer based on a double synergistic passivation strategy, a preparation method and application thereof, and belongs to the technical field of solar cells. By adding guanidinium chloride in a perovskite precursor solution, a 2D / 3D perovskite heterostructure can be formed, and the crystallization of the perovskite light-absorbing layer can be effectively regulated by constructing a 2D / 3D perovskite heterojunction; when a multi-active-site ligand molecule (a Lewis base molecule containing N and S electron donors) is continuously introduced into the heterojunction, the non-radiative recombination loss induced by the perovskite bulk phase and interface defects can be minimized. The perovskite light-absorbing layer based on the double synergistic passivation strategy is applied to a perovskite cell, so that the power conversion efficiency of the device is greatly improved, and the long-term operation stability and the humidity and heat stability of the device are ensured, and the achievement in the application is helpful to accelerating the commercial application of the perovskite solar cell.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and relates to a perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy, its preparation method, and its application. Background Technology

[0002] Inverted perovskite solar cells typically consist of a conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, a buffer layer, and a metal back electrode stacked from bottom to top. They have attracted considerable attention due to their advantages such as low fabrication temperature, good operational stability, and applicability to tandem photovoltaic devices. In recent years, researchers have continuously optimized the performance of inverted perovskite solar cells through composition engineering, process optimization, and interface engineering, resulting in significant progress in performance improvement. Although inverted perovskite solar cells have achieved a certified efficiency of 24.3%, defects in their bulk phase and interfaces lead to severe non-radiative recombination, making the realization of high-efficiency inverted perovskite solar cells a formidable challenge.

[0003] Fabricating high-quality perovskite thin films (perovskite light-absorbing layers) is crucial for realizing high-efficiency devices. The uncontrollable crystallization of perovskite, nonradiative recombination of charge carriers due to deep defects at grain boundaries, and the susceptibility of crystal planes to water and oxygen all contribute to the poor quality of perovskite films. Research shows that constructing 2D / 3D perovskite heterojunctions can effectively overcome these challenges. On the one hand, 2D perovskite can act as a seed to promote the nucleation and growth of 3D perovskite, thus effectively passivating defects at the crystal planes in 3D perovskite films; on the other hand, 2D perovskite can protect the crystal planes in 3D perovskite from water or oxygen. Currently, Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) type two-dimensional perovskites have been widely used to construct 2D / 3D perovskite heterojunctions. Since 2D perovskites typically exhibit higher exciton binding energies and lower carrier mobilities than 3D perovskites, maintaining a balance between carrier migration and stability is crucial in 2D / 3D perovskite heterostructures. Compared to RP-type and DJ-type 2D perovskites, novel 2D perovskites with alternating cations in the interlayer space (ACI) generally possess lower exciton binding energies, higher crystal symmetry, and shorter interlayer distances between adjacent inorganic plates, which are beneficial for carrier transport and transfer. Therefore, constructing ACI-type 2D / 3D perovskite heterostructures holds promise for further improving the photoelectric conversion efficiency and stability of inverted perovskite solar cells.

[0004] Besides crystallization and crystal faces affecting the preparation of high-quality perovskite films, the surface of perovskite films is also a crucial factor influencing their formation. This is because, on the one hand, the surface of perovskite films also contains numerous defects, leading to severe nonradiative recombination; on the other hand, perovskite films are highly reactive to moisture and oxygen, and their degradation typically begins at defect sites on the surface and in the perovskite layer (GB). To address perovskite film surface passivation, various interface-modifying molecules have been developed, such as Lewis base molecules, salt molecules, and 2D perovskites.

[0005] However, simply addressing the problems existing on the crystal planes or surfaces of perovskite thin films cannot maximize the performance of perovskite solar cells. Therefore, there is an urgent need to explore a feasible and effective method to synergistically modify the crystal planes and surfaces to maximize defect passivation capabilities, reduce bulk and interfacial nonradiative recombination losses, and thus greatly improve the photoelectric conversion efficiency and stability of the device. Summary of the Invention

[0006] In view of this, one objective of the present invention is to provide a method for preparing a perovskite light-absorbing layer based on a dual synergistic passivation strategy; a second objective of the present invention is to provide a perovskite light-absorbing layer based on a dual synergistic passivation strategy; a third objective of the present invention is to provide the application of the perovskite light-absorbing layer based on a dual synergistic passivation strategy in inverted perovskite solar cells; a fourth objective of the present invention is to provide an inverted perovskite solar cell; and a fifth objective of the present invention is to provide a method for preparing an inverted perovskite solar cell.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] 1. A method for preparing a perovskite light-absorbing layer based on a dual synergistic passivation strategy, the method being as follows: Guanidine chloride is added to an ABX3 type perovskite precursor solution, followed by spin coating. 3–15 s before the end of spin coating, chlorobenzene is sprayed and the mixture is annealed to form a thin film with a 2D / 3D perovskite heterostructure. A multi-active-site ligand molecule solution with a concentration of 0.01–10 mg / mL is then spin-coated onto the thin film. 5 s before the end of spin coating, chlorobenzene is sprayed and the mixture is annealed to obtain the perovskite light-absorbing layer based on the dual synergistic passivation strategy.

[0009] In the ABX3 type perovskite precursor solution, A is CH3NH3. + CH(NH2)2 + Cs + or Rb + Any one or more of the following; B is Pb 2+ Sn 2+ Or Ge 2+ Any one or more of them; X is Cl -,Br - Or I - Any one or more of the following; the multi-active-site ligand molecule is a Lewis base molecule that simultaneously contains N and S electron donors.

[0010] Preferably, the 2D / 3D perovskite heterostructure is composed of 3D perovskite and 2D perovskite from top to bottom; the chemical formula of the 2D perovskite is (GA)A. n B n X 3n+1 The chemical formula of the 3D perovskite is ABX3.

[0011] Where n is an integer ≥ 1; GA is CH6N3 + .

[0012] Preferably, the solvent in the ABX3 perovskite precursor solution is any one or two of N,N-dimethylformamide or dimethyl sulfoxide; the multi-active-site ligand molecule is 2-mercapto-1,3,4-thiadiazole; and the solvent in the multi-active-site ligand molecule solution is any one or more of dichloromethane, chloroform, chlorobenzene, dichlorobenzene, toluene, ethyl acetate, diethyl ether, anisole, or isopropanol.

[0013] Preferably, guanidine chloride is added to the ABX3 type perovskite precursor solution, and then spin-coated at a speed of 2000-6000 rpm for 20-60 s, and annealed at 100-150℃ for 5-30 min; a multi-active-site ligand molecule solution with a concentration of 0.01-10 mg / mL is spin-coated at a speed of 3000-6000 rpm for 30-60 s, and annealed at 100℃ for 5 min.

[0014] Preferably, in forming a thin film with a 2D / 3D perovskite heterostructure, the mass ratio of the ABX3 type perovskite precursor solution to guanidine chloride is 700–1200:0.01–5.0; the mass ratio of chlorobenzene to guanidine chloride is 10–301:3–6; and in constructing a perovskite light-absorbing layer, the mass ratio of chlorobenzene to multi-active-site ligand molecules is 100–5000:0.1–5.

[0015] 2. The perovskite light-absorbing layer prepared by the method based on a dual synergistic passivation strategy.

[0016] 3. Application of the perovskite light-absorbing layer in inverted perovskite solar cells.

[0017] 4. An inverted perovskite solar cell, wherein the inverted perovskite solar cell comprises, from bottom to top, a conductive substrate layer, a hole transport layer, an interface modification layer, the perovskite light-absorbing layer, an electron transport layer, a cathode interface layer, and a back electrode.

[0018] Preferably, the conductive substrate layer is made of either ITO or FTO; the hole transport layer is made of either or more of the following: poly(3,4-ethylenedioxythiophene / polystyrene sulfonate), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3-hexylthiophene-2,5-diyl), cuprous thiocyanate, cuprous iodide, or nickel oxide nanoparticles; the interface modification layer is made of Al2O3; and the electron transport layer is made of [6,6]-phenyl-C 61 The cathode interface layer is made of one or more of the following materials: methyl butyrate, tin dioxide, titanium dioxide, zinc oxide, barium stannate, or cerium dioxide; the cathode interface layer is made of one or more of the following materials: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, zirconium acetylacetonate, or lithium fluoride; and the back electrode is made of one or more of the following materials: gold, silver, copper, aluminum, or low-temperature carbon.

[0019] 5. The method for fabricating the inverted perovskite solar cell, wherein the fabrication method is as follows:

[0020] (1) Disperse the hole transport layer material in water, filter it through polyvinylidene fluoride, and drop it onto the pretreated conductive substrate. Spin coat it at a speed of 3000-6000 rpm for 20-60 seconds, and anneal it at 100-200℃ for 10-30 minutes to form a hole transport layer on the surface of the pretreated conductive substrate.

[0021] (2) Disperse the material of the interface modification layer in isopropanol, and then drop it onto the hole transport layer described in step (1). Spin coat it at a speed of 2000-8000 rpm for 10-30 seconds to form an interface modification layer on the surface of the hole transport layer.

[0022] (3) Add guanidine chloride to the ABX3 type perovskite precursor solution, and then spin-coat it onto the interface modification layer described in step (2). Spray chlorobenzene 3 to 15 seconds before the end of spin-coating and then anneal to form a film containing 2D / 3D perovskite heterojunction. Then spin-coat a multi-active site ligand molecule solution with a concentration of 0.01 to 10 mg / mL onto the film. Spray chlorobenzene 5 seconds before the end of spin-coating and then anneal to form the perovskite light-absorbing layer on the surface of the interface modification layer.

[0023] (4) Dissolve the electron transport layer material in chlorobenzene, filter it through polyvinylidene fluoride and drop it onto the perovskite light-absorbing layer described in step (3). Spin coat it at a speed of 2000-4000 rpm for 30-60 seconds to form an electron transport layer on the surface of the perovskite light-absorbing layer.

[0024] (5) Dissolve the cathode interface layer material in isopropanol, and then drop it onto the electron transport layer described in step (4). Spin coat it at a speed of 3000-6000 rpm for 10-40 seconds to form a cathode interface layer on the surface of the electron transport layer.

[0025] (6) Place the material of the back electrode with a thickness of 80-120 nm on the cathode interface layer described in step (5), and then perform vacuum thermal evaporation to form the back electrode on the surface of the cathode interface layer.

[0026] The beneficial effects of this invention are as follows: This invention provides a perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy. The specific preparation method of this perovskite light-absorbing layer is as follows: in an ABX3 type perovskite precursor solution (A is CH3NH3)... + CH(NH2)2 + Cs + or Rb + Any one or more of the following; B is Pb 2+ Sn 2+ Or Ge 2+ Any one or more of them; X is Cl - ,Br - Or I - After adding guanidine chloride to any one or more of the following solutions, spin-coating is performed. Before finishing the spin-coating, chlorobenzene is sprayed on and the solution is annealed to form a thin film containing a 2D / 3D perovskite heterostructure. A solution of multi-active-site ligand molecules (Lewis base molecules containing both N and S electron donors) is then spin-coated onto this film, and chlorobenzene is sprayed on again before finishing the spin-coating and annealed. Adding guanidine chloride to the perovskite precursor solution enables the in-situ formation of a bottom-up 2D / 3D perovskite heterostructure at the buried interface. Simultaneously, the interface treatment with multi-active-site Lewis base ligand molecules effectively regulates perovskite crystallization kinetics, passivates interface defects, increases carrier lifetime, and effectively suppresses non-radiative recombination of interface carriers.

[0027] This invention also provides an inverted perovskite solar cell. The solar cell fabricated using a perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy achieves a power conversion efficiency (PCE) of 24.58%. After aging at 45–65% relative humidity for 3000 hours, the unencapsulated device retains 90.5% of its initial PCE; after aging under continuous illumination for 1000 hours, it retains 85.8% of its initial PCE; and after aging in nitrogen at 85°C for 840 hours, it retains 81.2% of its initial PCE. This demonstrates that the solar cell fabricated using the perovskite light-absorbing layer constructed based on the dual synergistic passivation strategy exhibits significantly improved power conversion efficiency and stability, enabling controllable fabrication of high-efficiency and stable perovskite solar cells. The technology disclosed in this invention has significant implications for accelerating the commercial application of perovskite solar cells.

[0028] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0030] Figure 1 The X-ray powder diffraction patterns are shown for the thin films in Examples 1-2 and Comparative Example 1 (Control).

[0031] Figure 2 The images are grazing incidence wide-angle X-ray scattering patterns corresponding to the thin films in Examples 1-2 and Comparative Example 1 (Control), where a is the grazing incidence wide-angle X-ray scattering pattern corresponding to the thin film in Comparative Example 1 (Control) and b is the grazing incidence wide-angle X-ray scattering pattern corresponding to the thin films in Examples 1-2.

[0032] Figure 3 The fluorescence spectra of the thin films in Examples 1-2 and Comparative Example 1 (Control) are shown below.

[0033] Figure 4 The ultraviolet absorption spectra of the thin films in Examples 1-2 and Comparative Example 1 (Control) are shown below;

[0034] Figure 5The images show the characteristic orbital spectra of elements in the thin film (perovskite) in Comparative Example 1, the thin film modified with 2-mercapto-1,3,4-thiadiazole (perovskite+MTD) in Comparative Example 3, and 2-mercapto-1,3,4-thiadiazole (MTD). Among them, a is the characteristic orbital spectra of the 2p orbital of the S element in perovskite, perovskite+MTD, and MTD; b is the characteristic orbital spectra of the 4f orbital of the Pb element in perovskite and perovskite+MTD; and c is the characteristic orbital spectra of the 1s orbital of the N element in perovskite, perovskite+MTD, and MTD.

[0035] Figure 6 The fluorescence spectra of the perovskite absorbing layers in Example 1, Comparative Example 1 (Control), and Comparative Examples 2-3 are shown.

[0036] Figure 7 The time-resolved photoluminescence spectra of the perovskite light-absorbing layers in Example 1, Comparative Example 1 (Control), and Comparative Examples 2-3 are shown.

[0037] Figure 8 The diagram shows the space charge confinement current-voltage relationship for the perovskite light-absorbing layer in Example 1, Comparative Example 1 (Control), and Comparative Examples 2-3.

[0038] Figure 9 V represents the perovskite light-absorbing layer in Example 1, Comparative Example 1 (Control), and Comparative Examples 2-3. OC A graph showing the effect of light intensity on light intensity;

[0039] Figure 10 The images show a schematic diagram and a high-resolution transmission electron microscope (TEM) image of the cross-section of the inverted perovskite solar cell in Example 3, where a is a schematic diagram and b is a TEM image.

[0040] Figure 11 The statistical histograms are for the photoelectric conversion efficiency of the inverted perovskite solar cells in Example 3, Comparative Example 4 (Control), and Comparative Examples 5-6.

[0041] Figure 12The JV curves for forward scan (RS) and reverse scan (FS) of the perovskite solar cells in Example 3, Comparative Example 4 (Control), and Comparative Examples 5-6 are shown below. Specifically, a is the JV curve for forward scan and reverse scan of the solar cell in Comparative Example 4 (Control), b is the JV curve for forward scan and reverse scan of the solar cell in Comparative Example 5, c is the JV curve for forward scan and reverse scan of the solar cell in Comparative Example 6, and d is the JV curve for forward scan and reverse scan of the solar cell in Example 3.

[0042] Figure 13 The following are stability test graphs of the perovskite solar cells in Example 3, Comparative Example 4 (Control), and Comparative Examples 5-6: a is the humidity stability graph of each unencapsulated device at room temperature with a relative humidity of 45-65% (RH); b is the light stability graph of each unencapsulated device under one-sun illumination; and c is the thermal stability graph of each unencapsulated device at 85°C in darkness. Detailed Implementation

[0043] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0044] Example 1

[0045] A perovskite light-absorbing layer based on a dual synergistic passivation strategy is prepared using the following method:

[0046] 228.4 mg FAI, 18.2 mg CsI, and 645.4 mg PbI2 were dissolved in a mixed solvent of 800 μL N,N-dimethylformamide and 200 μL dimethyl sulfoxide. After shaking for 10 min, the solution was filtered through polytetrafluoroethylene to obtain CsI. 0.05 FA 0.95Take 1 mL of the PbI3 precursor solution and add 1.0 mg of guanidine chloride (GACl) to form a guanidine chloride precursor solution with a concentration of 1.0 mg / mL. Place the solution on a glass substrate and spin-coat at 5000 rpm for 40 s. Spray 100 μL of chlorobenzene 5 s before the end of spin-coating. Then anneal at 100 °C for 30 min to form a film with a 2D / 3D perovskite heterostructure. Continue spin-coating a 2 mg / mL diethyl ether solution of 2-mercapto-1,3,4-thiadiazole (MTD) on the film at 5000 rpm. After spin-coating for 10 s, anneal at 100 °C for 5 min to obtain a perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy.

[0047] Example 2

[0048] The difference from Example 1 is that 1.0 mg GACl is replaced with 4.0 mg GACl.

[0049] Comparative Example 1

[0050] 228.4 mg FAI, 18.2 mg CsI, and 645.4 mg PbI2 were dissolved in a mixed solvent of 800 μL N,N-dimethylformamide and 200 μL dimethyl sulfoxide. After shaking for 10 min, the solution was filtered through polytetrafluoroethylene to obtain CsI. 0.05 FA 0.95 The PbI3 precursor solution was placed on a glass substrate and spin-coated at 5000 rpm for 40 seconds. 100 μL of chlorobenzene was sprayed 5 seconds before the end of the spin-coating, and then annealed at 100 °C for 30 minutes to form a thin film (which can also be called a perovskite light-absorbing layer).

[0051] Comparative Example 2

[0052] The difference from Example 1 is that the ether solution of 2-mercapto-1,3,4-thiadiazole (MTD) is not added.

[0053] Comparative Example 3

[0054] The difference from Example 1 is that guanidine chloride is not added.

[0055] X-ray powder diffraction, grazing incidence wide-angle X-ray scattering, fluorescence, and ultraviolet spectroscopy were performed on the thin films in Examples 1-2 and Comparative Example 1 (Control). The experimental results are as follows: Figures 1-4 As shown. Among them, Figure 1 The X-ray powder diffraction patterns are shown for the thin films in Examples 1-2 and Comparative Example 1 (Control). Figure 2The images are grazing incidence wide-angle X-ray scattering patterns corresponding to the thin films in Examples 1-2 and Comparative Example 1 (Control), where a is the grazing incidence wide-angle X-ray scattering pattern corresponding to the thin film in Comparative Example 1 (Control) and b is the grazing incidence wide-angle X-ray scattering pattern corresponding to the thin films in Examples 1-2. Figure 3 The fluorescence spectra of the thin films in Examples 1-2 and Comparative Example 1 (Control) are shown below. Figure 4 The images show the UV absorption spectra of the thin films in Examples 1-2 and Comparative Example 1 (Control). Figure 2 It can be seen that when different concentrations of guanidine chloride are added to the perovskite precursor solution, the 2D perovskite in the resulting 2D / 3D heterojunction is GA2PbI4 with n=1. From Figures 1-4 As can be seen from the figure, without the addition of guanidine chloride, there are no characteristic peaks representing 2D perovskite in the perovskite precursor solution. However, after the addition of guanidine chloride, different characteristic values ​​(n=1,2,3) of ACI-type 2D perovskite can be seen in each figure, thus confirming the existence of 2D / 3D perovskite heterojunction.

[0056] Figure 5 The images show the characteristic orbital spectra of elements in the film (perovskite) in Comparative Example 1, the film modified with 2-mercapto-1,3,4-thiadiazole (perovskite+MTD) in Comparative Example 3, and 2-mercapto-1,3,4-thiadiazole (MTD). Specifically, a represents the characteristic orbital spectra of the 2p orbital of S element in perovskite, perovskite+MTD, and MTD; b represents the characteristic orbital spectra of the 4f orbital of Pb element in perovskite and perovskite+MTD; and c represents the characteristic orbital spectra of the 1s orbital of N element in perovskite, perovskite+MTD, and MTD. Figure 5 It can be seen that MTD exists on the surface of perovskite, and the S and N atoms in MTD are related to the uncoordinated Pb atoms in the perovskite. 2+ It has a strong interaction force that can passivate deep-level defects, thereby suppressing non-radiative recombination in the perovskite light-absorbing layer.

[0057] Fluorescence spectroscopy was performed on the perovskite absorbing layers in Example 1 and Comparative Examples 1-3. The experimental results are as follows: Figure 6 As shown. From Figure 6 As can be seen, the perovskite absorbing layer modified with GACl+MTD exhibits a stronger fluorescence map, indicating that the quality of the perovskite absorbing layer is significantly improved under the dual synergistic effect of the two. Time-resolved photoluminescence spectroscopy tests were performed on the perovskite absorbing layers in Example 1 and Comparative Examples 1-3, and the experimental results are as follows: Figure 7 As shown. From Figure 7As can be seen, the perovskite film, after dual synergistic passivation with GACl and MTD, exhibits a longer carrier lifetime and a significant reduction in nonradiative recombination within the film. Space charge confinement current-voltage relationships were tested on the perovskite light-absorbing layers in Example 1 and Comparative Examples 1-3, and the experimental results are as follows: Figure 8 As shown. From Figure 8 As can be seen, the space charge confinement current (SCLC) method can be used to quantitatively analyze the effect of the GACl+MTD modifier on the defect state density in the perovskite film, and it was found that the reduction in defect state density in the perovskite film was most significant under the dual synergistic effect of the two modifiers. VL plots were drawn on the perovskite light-absorbing layers of Example 1 and Comparative Examples 1-3. OC The graph shows the function of light intensity, and the experimental results are as follows. Figure 9 As shown. From Figure 9 As can be seen, under the dual synergistic effect of GACl and MTD, the nonradiative recombination inside the perovskite film is significantly reduced, and the defect state density is reduced accordingly.

[0058] Example 3

[0059] A Cs 0.05 FA 0.95 The PbI3 inverted perovskite solar cell, from bottom to top, comprises an ITO conductive substrate layer, a nickel oxide hole transport layer, an Al2O3 interface modification layer, the perovskite light-absorbing layer as described in Example 2, and [6,6]-phenyl-C 61 -Methyl butyrate electron transport layer, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline cathode interface layer, and Ag back electrode. The specific preparation method is as follows:

[0060] (1) Select ITO transparent conductive glass with a resistance of 12Ω as the conductive substrate layer, and then clean it with detergent, deionized water, acetone and anhydrous ethanol in sequence for 20 minutes. After drying with N2, treat it under ultraviolet ozone for 15 minutes to obtain the pretreated ITO conductive substrate layer.

[0061] (2) Place 25mg of nickel oxide nanoparticles in 1mL of deionized water and shake for 5min. After sonication for 10min, filter through polyvinylidene fluoride to obtain a dispersion. Then drop the dispersion onto the ITO conductive substrate pretreated in step (1). Spin coat at 5000rpm for 30s and anneal at 150℃ for 10min to form a nickel oxide hole transport layer on the surface of the pretreated ITO conductive substrate.

[0062] (3) Add 1 mL of isopropanol to 20 μL of Al2O3 isopropanol solution with a mass percentage of 20 wt.% to obtain a hygroscopic alumina dispersion. Then drop the dispersion onto the nickel oxide hole transport layer in step (2). Spin coat at 5000 rpm for 30 s to form an Al2O3 interface modification layer on the surface of the nickel oxide hole transport layer.

[0063] (4) Dissolve 228.4 mg FAI, 18.2 mg CsI, and 645.4 mg PbI2 in a mixed solvent of 800 μL N,N-dimethylformamide and 200 μL dimethyl sulfoxide. After shaking for 10 min, filter through polytetrafluoroethylene to obtain the precursor solution. Take 1 mL of this precursor solution and add 4.0 mg A 4.0 mg / mL guanidine chloride precursor solution was formed by GACl. This solution was dropped onto the Al2O3 interface modification layer in step (3). After spin coating at 5000 rpm for 40 s, 100 μL of chlorobenzene was sprayed 5 s before the end of spin coating. Then, the film with 2D / 3D perovskite heterostructure was formed by annealing at 100℃ for 30 min. A 2 mg / mL ether solution of 2-mercapto-1,3,4-thiadiazole was dropped onto the film. After spin coating at 5000 rpm for 10 s, the film was annealed at 100℃ for 5 min to form a modified perovskite light-absorbing layer on the surface of the Al2O3 interface modification layer.

[0064] (5) 23 mg of [6,6]-phenyl-C 61 Methyl butyrate was dissolved in 1 mL of chlorobenzene, shaken, and filtered through polytetrafluoroethylene to obtain the filtrate. The filtrate was then dropped onto the perovskite light-absorbing layer in step (4), and spin-coated at 2500 rpm for 40 s to form [6,6]-phenyl-C on the surface of the perovskite light-absorbing layer. 61 -Methyl butyrate electron transport layer;

[0065] (6) Dissolve 0.5 mg of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline in 1 mL of isopropanol to form a solution, and then add this solution dropwise to the [6,6]-phenyl-C in step (5). 61 On the methyl butyrate electron transport layer, spin-coating at 5000 rpm for 30 seconds can achieve [6,6]-phenyl-C 61 A 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline cathode interface layer is formed on the surface of the methyl butyrate electron transport layer.

[0066] (7) In high vacuum (5×10 -5At Pa), an Ag back electrode can be formed on the surface of the cathode interface layer by thermally evaporating Ag with a thickness of 100 nm onto the 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline cathode interface layer in step (6).

[0067] Figure 10 In Example 3, 'a' represents Cs. 0.05 FA 0.95 A schematic diagram of the structure of a PbI3 inverted perovskite solar cell, where b is its transmission electron microscope image. (Combined with...) Figure 10 As can be seen from a and b, 2D perovskite mainly exists at the grain boundaries of 3D perovskite, thus forming a 2D / 3D perovskite heterojunction structure at the grain boundaries.

[0068] Comparative Example 4

[0069] The difference from Example 3 is that in step (4), the ether solution of guanidine chloride and 2-mercapto-1,3,4-thiadiazole is not added (Control).

[0070] Comparative Example 5

[0071] The difference from Example 3 is that the ether solution of 2-mercapto-1,3,4-thiadiazole is not added in step (4).

[0072] Comparative Example 6

[0073] The difference from Example 3 is that guanidine chloride is not added in step (4).

[0074] Figure 11 The above are statistical histograms of the photoelectric conversion efficiency of the inverted perovskite solar cells in Example 3, Comparative Example 4 (Control), and Comparative Examples 5-6. From... Figure 11 As can be seen, the efficiency of the perovskite solar cell after dual synergistic modification with GACl and MTD is significantly improved, and it has high repeatability.

[0075] Forward scan (RS) and reverse scan (FS) were performed on the perovskite solar cells in Example 3, Comparative Example 4 (Control), and Comparative Examples 5-6, and JV curves were plotted. The experimental results are as follows: Figure 12 As shown. Among them Figure 12 Figure a shows the JV curves for the forward and reverse scans of the solar cell in Comparative Example 4 (Control). As can be seen from the figure, the unmodified perovskite solar cell achieved a photoelectric conversion efficiency of 21.84%, with a short-circuit current density (JV) of [missing value]. SC The value is 24.28 mA / cm. 2 Open circuit voltage (V) OCThe voltage is 1.100V, and the fill factor (FF) is 78.85%. Figure 12 Figure b shows the JV curves for the forward and reverse scans of the solar cell in Comparative Example 5. As can be seen from the figure, the perovskite solar cell modified with GAC1 achieved a photoelectric conversion efficiency of 23.61%, with a short-circuit current density (J / V) of [missing value]. SC The value is 25.13 mA / cm. 2 Open circuit voltage (V) OC The voltage is 1.148V, and the fill factor (FF) is 81.81%. Figure 12 Figure c shows the JV curves for the forward and reverse scans of the solar cell in Comparative Example 6. As can be seen from the figure, the perovskite solar cell modified by MTD achieved a photoelectric conversion efficiency of 22.57%, with a short-circuit current density (JV) of [missing value]. SC The value is 24.77 mA / cm. 2 Open circuit voltage (V) OC The voltage is 1.132V, and the fill factor (FF) is 80.52%. Figure 12 Figure d shows the JV curves for the forward and reverse scans of the solar cell in Example 3. As can be seen from the figure, the perovskite solar cell modified with both GAC1 and MTD achieved a photoelectric conversion efficiency of 24.58%, with a short-circuit current density (J / V) of [missing value]. SC The value is 25.96 mA / cm. 2 Open circuit voltage (V) OC The voltage is 1.156V, and the fill factor (FF) is 81.91%.

[0076] Stability tests were conducted on the perovskite solar cells in Example 3 and Comparative Examples 4-6, and the experimental results are as follows: Figure 13 As shown. Among them Figure 13 Figure a shows the humidity stability of each unencapsulated device at room temperature with a relative humidity of 45-65% (RH). As can be seen from the figure, the unencapsulated perovskite solar cells modified by GAC1 and MTD retained 90.5% of their initial efficiency after aging at a relative humidity of 45-65% for 3000 hours. Figure 13 Figure b shows the photostability of each unencapsulated device under one sun. As can be seen from the figure, the unencapsulated perovskite solar cell modified by GAC1 and MTD retains 85.8% of its initial efficiency after aging under continuous light for 1000 hours. Figure 13Figure c shows the thermal stability of each unencapsulated device at 85°C in the dark. As can be seen from the figure, the unencapsulated perovskite solar cell modified with GAC1 and MTD retained 81.2% of its initial photoelectric conversion efficiency after aging in N2 at 85°C for 840 hours. In summary, the damp-heat stability of the device was significantly improved after dual synergistic modification.

[0077] In summary, this invention provides a perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy. The addition of guanidine chloride enables the formation of a bottom-up 2D / 3D perovskite heterojunction. Simultaneously, interface treatment with multi-active-site Lewis base ligands effectively regulates perovskite crystallization kinetics, passivates interface defects, increases carrier lifetime, and effectively suppresses nonradiative recombination of interface carriers. Perovskite solar cells constructed based on this perovskite light-absorbing layer achieve a photoelectric conversion efficiency of 24.58%. After aging at 45–65% relative humidity for 3000 hours, the unencapsulated device retains 90.5% of its initial efficiency; after aging under continuous illumination for 1000 hours, it retains 85.8% of its initial efficiency; and after aging at 85°C in N2 for 840 hours, it retains 81.2% of its initial efficiency. The technology disclosed in this invention has significant implications for accelerating the commercial application of perovskite solar cells.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a perovskite light-absorbing layer based on a dual synergistic passivation strategy, characterized in that: The preparation method is as follows: Guanidine chloride is added to ABX3 type perovskite precursor solution, and then spin-coated. Chlorobenzene is sprayed 3-15s before the end of spin-coating and then annealed to form a film with 2D / 3D perovskite heterostructure. Then, a multi-active site ligand molecule solution with a concentration of 0.01-10mg / mL is spin-coated onto the film. Chlorobenzene is sprayed 5s before the end of spin-coating and then annealed to obtain a perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy. In the ABX3 type perovskite precursor solution, A is CH3NH3. + CH(NH2)2 + Cs + or Rb + Any one or more of the following; B is Pb 2+ Sn 2+ Or Ge 2+ Any one or more of them; X is Cl - ,Br - Or I - Any one or more of the following; the multi-active-site ligand molecule is a Lewis base molecule that simultaneously contains N and S electron donors; The solvent in the ABX3 perovskite precursor solution is any one or two of N,N-dimethylformamide or dimethyl sulfoxide; the multi-active-site ligand molecule is 2-mercapto-1,3,4-thiadiazole; the solvent in the multi-active-site ligand molecule solution is any one or more of dichloromethane, chloroform, chlorobenzene, dichlorobenzene, toluene, ethyl acetate, diethyl ether, anisole, or isopropanol.

2. The preparation method according to claim 1, characterized in that: The 2D / 3D perovskite heterostructure is composed of 3D perovskite and 2D perovskite from top to bottom; the chemical formula of the 2D perovskite is (GA)A. n B n X 3n+1 The chemical formula of the 3D perovskite is ABX3. Where n is an integer ≥ 1; GA is CH6N3 + .

3. The preparation method according to claim 1, characterized in that: Guanidine chloride was added to the ABX3 perovskite precursor solution, and then spin-coated at 2000-6000 rpm for 20-60 s, followed by annealing at 100-150°C for 5-30 min. A multi-active-site ligand molecule solution with a concentration of 0.01-10 mg / mL was spin-coated at 3000-6000 rpm for 30-60 s, followed by annealing at 100°C for 5 min.

4. The preparation method according to claim 1, characterized in that: In forming a thin film with a 2D / 3D perovskite heterostructure, the mass ratio of the ABX3 type perovskite precursor solution to guanidine chloride is 700~1200:0.01~5.0; the mass ratio of chlorobenzene to guanidine chloride is 10~301:3~6; and in constructing a perovskite light-absorbing layer, the mass ratio of chlorobenzene to multi-active-site ligand molecules is 100~5000:0.1~5.

5. The perovskite light-absorbing layer constructed based on a dual synergistic passivation strategy prepared by the method according to any one of claims 1 to 4.

6. The application of the perovskite light-absorbing layer according to claim 5 in an inverted perovskite solar cell.

7. An inverted perovskite solar cell, wherein the inverted perovskite solar cell comprises, from bottom to top, a conductive substrate layer, a hole transport layer, an interface modification layer, a perovskite light-absorbing layer, an electron transport layer, a cathode interface layer, and a back electrode, characterized in that: The perovskite light-absorbing layer is the perovskite light-absorbing layer as described in claim 5.

8. The inverted perovskite solar cell according to claim 7, characterized in that: The conductive substrate layer is made of either ITO or FTO; the hole transport layer is made of either or more of the following: poly(3,4-ethylenedioxythiophene / polystyrene sulfonate), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], poly(3-hexylthiophene-2,5-diyl), cuprous thiocyanate, cuprous iodide, or nickel oxide nanoparticles; the interface modification layer is made of Al2O3; and the electron transport layer is made of [6,6]-phenyl-C 61 The cathode interface layer is made of one or more of the following materials: methyl butyrate, tin dioxide, titanium dioxide, zinc oxide, barium stannate, or cerium dioxide; the cathode interface layer is made of one or more of the following materials: 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, zirconium acetylacetonate, or lithium fluoride; and the back electrode is made of one or more of the following materials: gold, silver, copper, aluminum, or low-temperature carbon.

9. The method for preparing the inverted perovskite solar cell according to claim 7 or 8, characterized in that: The preparation method is as follows: (1) Disperse the hole transport layer material in water, filter it through polyvinylidene fluoride, and drop it onto the pretreated conductive substrate. Spin coat it at a speed of 3000~6000 rpm for 20~60s, and anneal it at 100~200°C for 10~30min to form a hole transport layer on the surface of the pretreated conductive substrate. (2) Disperse the material of the interface modification layer in isopropanol, and then drop it onto the hole transport layer described in step (1). Spin coat it at a speed of 2000~8000 rpm for 10~30s to form an interface modification layer on the surface of the hole transport layer. (3) Add guanidine chloride to the ABX3 type perovskite precursor solution, and then spin-coat it onto the interface modification layer described in step (2). Spray chlorobenzene 3 to 15 seconds before the end of spin-coating and then anneal to form a film containing 2D / 3D perovskite heterojunction. Then spin-coat a multi-active site ligand molecule solution with a concentration of 0.01 to 10 mg / mL onto the film. Spray chlorobenzene 5 seconds before the end of spin-coating and then anneal to form a perovskite light-absorbing layer on the surface of the interface modification layer, i.e., the perovskite light-absorbing layer described in claim 6. (4) Dissolve the electron transport layer material in chlorobenzene, filter it through polyvinylidene fluoride and drop it onto the perovskite light-absorbing layer described in step (3). Spin coat it at a speed of 2000~4000 rpm for 30~60s to form an electron transport layer on the surface of the perovskite light-absorbing layer. (5) Dissolve the cathode interface layer material in isopropanol, and then drop it onto the electron transport layer described in step (4). Spin coat it at a speed of 3000~6000 rpm for 10~40s to form a cathode interface layer on the surface of the electron transport layer. (6) Place the material of the back electrode with a thickness of 80~120nm on the cathode interface layer described in step (5), and then perform vacuum thermal evaporation to form the back electrode on the surface of the cathode interface layer.

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