A method for preparing a perovskite solar cell

Abstract

The application relates to a preparation method of a perovskite solar cell, which comprises the following steps: providing conductive glass; preparing an electron transport layer on the conductive glass; preparing a perovskite precursor solution containing 0.1-1 mg / mL Pt-MOF, coating the electron transport layer to prepare a perovskite light-absorbing layer; preparing a two-dimensional passivation layer on the light-absorbing layer; preparing a hole transport layer on the passivation layer; and evaporating a metal electrode on the hole transport layer. The application also relates to the perovskite solar cell prepared by the above preparation method. In the preparation process of the perovskite solar cell, Pt-MOF is introduced into the perovskite light-absorbing layer, so that the problems of insufficient stability of the existing battery, uncontrollable perovskite crystallization and difficulty in simultaneously improving the efficiency and stability of the additive are solved. The Pt-MOF can control the crystallization, reduce defects and enhance hydrophobicity, and the layers are synergistically optimized, so that the photoelectric conversion efficiency and long-term stability of the battery are simultaneously improved, thereby laying a foundation for commercialization.

Description

TECHNICAL FIELD

[0001] The present application relates to a solar cell, more particularly to a preparation method of a perovskite solar cell. BACKGROUND

[0002] In the field of new energy, organic-inorganic hybrid perovskite solar cells (PSCs) have achieved rapid development in the past decade due to their excellent photovoltaic application potential. Since 2009, the photoelectric conversion efficiency (PCE) has continued to rise from the initial 3.8% to more than 27% in 2025, showing great commercial application prospects and becoming one of the research hotspots in the field of solar cell technology.

[0003] However, despite the significant improvement in the efficiency of organic-inorganic hybrid perovskite solar cells, the commercialization process still faces the core problem of insufficient stability. In actual application scenarios, perovskite materials are easily affected by external environmental factors. When exposed to high humidity, mechanical stress, high temperature, or continuous light, etc. Physical conditions, its structure and performance will rapidly deteriorate, resulting in a significant reduction in the service life of the battery device, making it difficult to meet the long-term reliability requirements of commercial products.

[0004] From the device structure and working principle, the perovskite active layer (also known as the perovskite light-absorbing layer, i.e. perovskite thin film) is the core place for PSCs to achieve photoelectric conversion and complete charge carrier separation and transport, so the control of the crystallization process and the surface morphology quality of this active layer directly determines the final performance of the battery device. Currently, the mainstream preparation method of perovskite thin film is solution method (i.e. solution system film formation), which has the advantages of simple operation and low cost, but has obvious defects in the preparation process: the growth process of crystal nucleus is difficult to control uniformly, and a large number of deep level defects are easily formed inside the thin film. These deep level defects can significantly hinder the effective transport of charge carriers, not only reducing the photoelectric conversion efficiency of the battery, but also further exacerbating the instability of the device performance, becoming a key factor restricting the performance improvement of perovskite solar cells.

[0005] To solve the above problems, the introduction of additives in the precursor solution has been widely proven to be one of the effective strategies to control the particle size of perovskite thin film, optimize the film morphology, and further improve the performance of battery devices. The types of additives used are diverse, including polymers, halide salts, perovskite nanomaterials, ionic liquids, and organic compounds, etc. These additives can to some extent promote the growth and fusion of crystal grains in the perovskite thin film, forming large-grained perovskite thin film and improving the film quality.

[0006] However, although the existing additives can improve the quality of the perovskite film, the crystallization quality of the perovskite film is still limited by the uncontrollable crystallization process even if a large-grained film is formed, and it is difficult to fundamentally solve the problem of synergistic improvement of the efficiency and stability of the perovskite solar cell. Therefore, it is a technical requirement to be solved in the field to develop a new type of efficient additive which can not only optimize the crystallization process and surface quality of the perovskite film, but also regulate the crystallization kinetics to enhance the stability of the device, so as to prepare a perovskite solar cell with higher efficiency and stability. SUMMARY

[0007] In order to solve the problems in the prior art that the additive cannot regulate the crystallization kinetics process of the perovskite, the present application aims to provide a preparation method of a perovskite solar cell.

[0008] The preparation method of the perovskite solar cell according to the present application comprises the following steps: S1, providing a conductive glass; S2, preparing an electron transport layer on the conductive glass; S3, preparing a perovskite precursor solution containing Pt-MOF, coating the perovskite precursor solution on the electron transport layer, and preparing a perovskite light-absorbing layer after reverse solvent treatment and annealing, wherein the concentration of Pt-MOF is in the range of 0.1 mg / mL-1 mg / mL, and the perovskite light-absorbing layer is a lead halide ternary perovskite doped with platinum metal organic framework containing inorganic-organic mixed cations; S4, preparing a two-dimensional passivation layer on the perovskite light-absorbing layer; S5, preparing a hole transport layer on the two-dimensional passivation layer; S6, evaporating a metal electrode on the hole transport layer to obtain a perovskite solar cell.

[0009] In a preferred embodiment, the conductive glass is ITO conductive glass, and the ITO conductive glass is subjected to cleaning treatment in step S1.

[0010] In a preferred embodiment, the material of the electron transport layer is selected from at least one of SnO2, ZnO and TiO2, and the electron transport layer is prepared by spin coating, spraying or evaporation in step S2, and is subjected to annealing treatment after preparation, wherein the annealing temperature is 120℃-180℃, and the annealing time is 20min-40min.

[0011] In a preferred embodiment, step S3 first comprises: dissolving a platinum source compound in an organic solvent, adding an organic ligand, an alkyl compound, an acid solution and a base solution, and obtaining Pt-MOF after heating reaction at 70℃-90℃. In a preferred embodiment, the platinum source compound is PtCl2·6H2O, the organic solvent is N-methyl pyrrolidone, the organic ligand is dipyrizinoquinoline-2,3,6,7,10,11-hexanol, the alkyl compound is hexaalkylcyclohexane, the acid solution is sulfuric acid solution, and the base solution is concentrated ammonia.

[0012] In a preferred embodiment, the perovskite precursor solution is made of organic cation halide and inorganic metal halide dissolved in mixed solvent, in step S3, the perovskite light-absorbing layer is prepared by spin-coating the perovskite precursor solution, and annealing treatment after preparation, the annealing temperature is 120-180℃, the annealing time is 10-20min, wherein the organic cation halide is selected from at least two of formamidinium halide and methylamine halide, the inorganic metal halide is PbI2 and CsI, the mixed solvent is a mixture of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), the concentration of the perovskite precursor solution is 1.5-1.9M. In a preferred embodiment, the organic cation halide is FAI, MABr and MACl.

[0013] In a preferred embodiment, the two-dimensional passivation layer is a PEAI passivation layer, in step S4, the PEAI passivation layer is prepared by spin-coating.

[0014] In a preferred embodiment, the hole transport layer is Spiro-OMeTAD, in step S5, the Spiro-OMeTAD hole transport layer is prepared by spin-coating.

[0015] In a preferred embodiment, the metal electrode is a silver electrode, a gold electrode or an aluminum electrode, and the thickness of the metal electrode is 100-120nm.

[0016] The perovskite solar cell obtained by the above preparation method of the present application is stacked from bottom to top in sequence: conductive glass, electron transport layer, perovskite light-absorbing layer containing Pt-MOF, two-dimensional passivation layer, hole transport layer and metal electrode.

[0017] In a preferred embodiment, the chemical composition of the perovskite light-absorbing layer is Cs 0.05 (FA 0.95 MA 0.05 ) 0.95 Pb(I 0.95 Br 0.05 )3.

[0018] The present application effectively solves the technical problems of insufficient stability of the perovskite solar cell (easily affected by high humidity, mechanical stress, high temperature or continuous light to cause structure and performance degradation), difficulty in controlling the crystallization process of the perovskite thin film prepared by the solution method (easily forming a large number of deep level defects to hinder the charge carrier transport and reduce the photoelectric conversion efficiency), and the existing additives cannot precisely control the crystallization kinetics to cause difficulty in balancing the efficiency and stability by introducing Pt-MOF with a concentration range of 0.1 mg / mL-1 mg / mL in the perovskite light-absorbing layer during the preparation of the perovskite solar cell, forming a lead halide ternary perovskite doped with platinum metal organic framework containing inorganic-organic mixed cations in the perovskite light-absorbing layer, and cooperating with the ordered preparation of the conductive glass, the electron transport layer, the two-dimensional passivation layer, the hole transport layer and the metal electrode. BRIEF DESCRIPTION OF DRAWINGS DETAILED DESCRIPTION OF THE INVENTION BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0020] Figure 1 UV-vis spectra of the perovskite solar cells according to Embodiment 1-Embodiment 5 of the present application.

[0021] Figure 2 SEM images of the perovskite solar cells according to Embodiment 1 and Embodiment 5 of the present application.

[0022] Figure 3 XPS images of the perovskite solar cells according to Embodiment 1 and Embodiment 5 of the present application.

[0023] Figure 4 GIWAXS images of the perovskite solar cells according to Embodiment 1 and Embodiment 5 of the present application.

[0024] Figure 5Current-voltage (J-V) characteristic curves of the perovskite solar cells according to Embodiment 1 and Embodiment 5 of the present application. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of the present application. Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings of the terms to those of ordinary skill in the art to which the present application belongs. The terms such as “comprise” and the like used herein are intended to encompass the elements or components appearing before the terms and the like listed after the terms, and equivalents thereof, and do not exclude other elements or components.

[0026] Embodiment 1

[0027] A multifunctional platinum-containing metal organic framework (Pt-MOF) doped perovskite solar cell has a bottom-up layered structure of ITO / SnO2 / Cs 0.05 (FA 0.95 MA 0.05 ) 0.95 Pb(I 0.95 Br 0.05 )3+Pt-MOF / PEAI / Spiro-OMeTAD / Ag

[0028] Indium tin oxide (ITO) conductive glass was sequentially cleaned with glass cleaner, deionized water, acetone and isopropanol solvents for 20 min. After ultrasonic cleaning, the glass was blown with nitrogen and cleaned with an ultraviolet ozone cleaning machine for 20 min.

[0029] A tin oxide (SnO2) solution was spin-coated onto the conductive surface of the ITO conductive glass at a speed of 4000 rpm, and annealed at 150°C for 30 min to obtain a SnO2 electron transport layer.

[0030] Dissolve 5 mg of platinum chloride hexahydrate (PtCl2·6H2O) in 80 mL of N-methyl pyrrolidone (NMP), then add to 10 mg of dipyrazinoquinolone-2,3,6,7,10,11-hexanol, 23.5 mg of hexaalkylcyclohexane, 15 mL of 2M sulfuric acid (H2SO4) and 3 mL of concentrated ammonia water (NH4OH) mixed solvent, and heat at 80°C for 6 h. Centrifuge the resulting brown-black crystals, wash in tetrahydrofuran, water, ethanol and acetone for 2 times each. The resulting product is dried at 120°C under vacuum overnight to remove water and adsorb solvents to obtain Pt-MOF black powder, i.e. Pt-MOF additive.

[0031] Weigh 263.114 mg of formamidinium iodide (FAI), 783.7 mg of lead iodide (PbI2), 9.517 mg of methylamine bromide (MABr), 22.083 mg of cesium iodide (CsI) and 20 mg of methylamine chloride (MACI), and dissolve CsI, MABr, FAI, MACI and PbI2 in a mixed solvent (DMF:DMSO=4:1, volume ratio) and stir at 55°C for 10 hours, filter with a disposable polytetrafluoroethylene filter to obtain a perovskite precursor solution with a concentration of 1.7M.

[0032] Add Pt-MOF additive to the perovskite precursor solution to obtain a Pt-MOF doped precursor solution with a concentration of 0.10 mg / mL.

[0033] Take the Pt-MOF doped precursor solution, spin-coat at a speed of 2000 rpm first, then switch to a speed of 6000 rpm, spin-coat onto the SnO2 electron transport layer, drop 18 s before the end of chlorobenzene anti-solvent, then anneal at 150°C for 15 min to form a cesium-doped formamidinium-methylamine lead iodide bromide ternary perovskite doped platinum metal-organic framework perovskite light-absorbing layer.

[0034] Take the phenethylammonium iodide (PEAI) solution and spin-coat it onto the perovskite light-absorbing layer at a speed of 5000 rpm to form a PEAI two-dimensional passivation layer.

[0035] Take the 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) solution and spin-coat it onto the PEAI two-dimensional passivation layer at a speed of 4000 rpm to form a Spiro-OMeTAD hole transport layer.

[0036] Evaporate Ag film on the Spiro-OMeTAD hole transport layer, control the film thickness to be 110 nm to form an Ag electrode.

[0037] Example 2

[0038] Unlike Example 1, the Pt-MOF doping concentration was adjusted to 0.30 mg / mL (only the amount of Pt-MOF added was changed, while the proportions of other precursor raw materials, solvent ratios, dissolution conditions, etc. were the same as in Example 1), and other preparation raw materials, steps, and process parameters (such as spin coating speed, annealing temperature, layered structure, etc.) remained the same.

[0039] Example 3

[0040] Unlike Example 1, the Pt-MOF doping concentration was adjusted to 0.50 mg / mL (only the amount of Pt-MOF added was changed, while the proportions of other precursor raw materials, solvent ratios, dissolution conditions, etc. were the same as in Example 1), and other preparation raw materials, steps, and process parameters (such as spin coating speed, annealing temperature, layered structure, etc.) remained the same.

[0041] Example 4

[0042] Unlike Example 1, the Pt-MOF doping concentration was adjusted to 1 mg / mL (only the amount of Pt-MOF added was changed, while the proportions of other precursor raw materials, solvent ratios, dissolution conditions, etc. were the same as in Example 1), and other preparation raw materials, steps, and process parameters (such as spin coating speed, annealing temperature, layered structure, etc.) remained the same.

[0043] Example 5

[0044] Unlike Example 1, no Pt-MOF additive was added. Only the exact same ternary perovskite precursor solution as in Example 1 was used. Other preparation materials, steps and process parameters (such as spin coating speed, annealing temperature, layered structure, etc.) were kept the same.

[0045] Performance test results analysis

[0046] The performance of the perovskite solar cells prepared in Examples 1-5 (including Pt-MOF doped and undoped control groups with different concentrations) was tested.

[0047] like Figure 1 As shown, the UV-Vis absorption spectroscopy reveals that the light absorption intensity of the perovskite film doped with Pt-MOF is significantly improved compared to the undoped control group. Furthermore, the UV-Vis light absorption capacity of the film reaches its maximum when the Pt-MOF doping concentration is 0.5 mg / mL, indicating that the introduction of Pt-MOF can optimize the sunlight capture efficiency of perovskite.

[0048] like Figure 2As shown in the scanning electron microscope (SEM) images, compared with the undoped control group, the perovskite grain size in the Pt-MOF-doped perovskite film is significantly increased and the crystallinity is significantly improved, indicating that Pt-MOF can effectively promote grain growth and fusion, and improve the microstructure of the film.

[0049] like Figure 3 As shown in the X-ray photoelectron spectroscopy (XPS) image, the characteristic peak of Pb 4f in the Pt-MOF-doped perovskite film shifts towards lower binding energies, confirming the binding of Pb in the perovskite with Pt-MOF. 2+ Strong chemical interactions exist, which passivate deep-level defects in the thin film and reduce charge carrier recombination.

[0050] like Figure 4 As shown in the in-situ grazing incidence wide-angle X-ray scattering (GIWAXS) diagram, it can be seen that after antisolvent treatment, the precursor phase of the undoped control group gradually disappears, and various intermediate phases and perovskite black phase are gradually formed, with incomplete transformation of the intermediate phase. In contrast, the perovskite film doped with Pt-MOF does not generate any intermediate phase after antisolvent treatment, and the formation process of the perovskite black phase is delayed. This indicates that Pt-MOF can regulate crystallization kinetics, slow down the nucleation rate, avoid intermediate phase residue, and is conducive to the formation of large-size, highly crystalline perovskite grains.

[0051] like Figure 5 As shown in the figure, calculations based on the current-voltage (JV) characteristic curves reveal that Pt-MOF doping significantly improves the photoelectric conversion efficiency of perovskite solar cells. The optimal device performance is achieved when the Pt-MOF doping concentration is 0.5 mg / mL, resulting in a power conversion efficiency (PCE) of 24.70% and a corresponding short-circuit current density (JV). SC ) Reaching 25.79 mA·cm -2 Open circuit voltage (V) OC The voltage is 1.182V, which is far superior to the undoped control group device.

[0052] Thus, by introducing a multifunctional Pt-MOF into the perovskite light-absorbing layer, this invention achieves multidimensional optimization of the performance of perovskite solar cells.

[0053] First, Pt-MOF can interact specifically with perovskite precursors, thereby slowing down the nucleation rate and inhibiting the formation of ineffective intermediate phases, regulating the crystallization kinetics of perovskite, promoting the formation of large-sized, highly crystalline perovskite grains, and optimizing film quality from a structural perspective.

[0054] Secondly, the C=O in Pt-MOF can interact with the unsaturated Pb in the perovskite. 2+Forming coordinate bonds effectively fills deep-level defects (such as PbI2 residual defects) on and inside the thin film surface, reduces nonradiative recombination of photogenerated electron-hole pairs, and improves charge utilization efficiency.

[0055] Moreover, Pt-MOF itself has good conductivity, which improves the electron mobility of the perovskite layer; at the same time, it can balance the transport rates of electrons and holes, suppress charge loss caused by ion migration, and directly improve the short-circuit current and fill factor of the battery.

[0056] In addition, the hydrophobic framework of Pt-MOF can form a physical barrier on the perovskite surface, reducing the erosion of external water vapor and oxygen; at the same time, its strong interaction with perovskite can stabilize the crystal structure, delay the performance degradation under long-term light exposure and high temperature conditions, and significantly extend the device life.

[0057] In summary, Pt-MOF comprehensively improves the overall performance of perovskite solar cells through multiple synergistic effects, including regulating crystallization kinetics, passivating defects, optimizing charge transport, and enhancing stability. Among these effects, the doping concentration of 0.5 mg / mL is the most effective.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A method for preparing a perovskite solar cell, characterized by, The preparation method comprises the following steps: S1, providing a conductive glass; S2, preparing an electron transport layer on the conductive glass; S3, dissolving a platinum source compound in an organic solvent, adding an organic ligand, an alkyl compound, an acid solution and a base solution, heating and reacting at 70-90 DEG C to obtain a Pt-MOF, then preparing a perovskite precursor solution containing the Pt-MOF, coating the perovskite precursor solution on the electron transport layer, and preparing a perovskite light-absorbing layer through anti-solvent treatment and annealing, wherein the concentration of the Pt-MOF is 0.1-1 mg / mL, and the perovskite light-absorbing layer is a lead halide ternary perovskite doped with a platinum metal organic framework containing inorganic-organic mixed cations; S4, preparing a two-dimensional passivation layer on the perovskite light-absorbing layer; S5, preparing a hole transport layer on the two-dimensional passivation layer; S6, evaporating a metal electrode on the hole transport layer to obtain a perovskite solar cell.

2. The production method according to claim 1, characterized by, The conductive glass is ITO conductive glass, and the ITO conductive glass is subjected to cleaning treatment in step S1.

3. The preparation method according to claim 1, characterized in that, The material of the electron transport layer is selected from at least one of SnO2, ZnO and TiO2, and the electron transport layer is prepared by spin coating, spraying or evaporation in step S2, and is subjected to annealing treatment after preparation, wherein the annealing temperature is 120-180 DEG C, and the annealing time is 20-40 min.

4. The method of claim 1, wherein, The perovskite precursor solution is prepared by dissolving organic cation halides and inorganic metal halides in a mixed solvent, and the perovskite light-absorbing layer is prepared by spin coating the perovskite precursor solution in step S3, and is subjected to annealing treatment after preparation, wherein the annealing temperature is 120-180 DEG C, the annealing time is 10-20 min, the organic cation halides are selected from at least two of formamidinium halide and methylamine halide, the inorganic metal halides are PbI2 and CsI, the mixed solvent is a mixture of N, N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and the concentration of the perovskite precursor solution is 1.5-1.9 M.

5. The preparation method according to claim 1, characterized in that, The two-dimensional passivation layer is a PEAI passivation layer, and the PEAI passivation layer is prepared by spin coating in step S4.

6. The method of claim 1, wherein, The hole transport layer is Spiro-OMeTAD, and the Spiro-OMeTAD hole transport layer is prepared by spin coating in step S5.

7. The preparation method according to claim 1, characterized in that, The metal electrode is a silver electrode, a gold electrode or an aluminum electrode, and the thickness of the metal electrode is 100-120 nm.

8. The perovskite solar cell prepared according to the method of any one of claims 1-7, characterized in that, The perovskite solar cell is stacked from bottom to top as follows: the conductive glass, the electron transport layer, the perovskite light-absorbing layer containing the Pt-MOF, the two-dimensional passivation layer, the hole transport layer and the metal electrode.

9. The perovskite solar cell according to claim 8, characterized in that, The chemical composition of the lead halide ternary perovskite in the perovskite light absorbing layer is Cs 0.05 (FA 0.95 MA 0.05 ) 0.95 Pb(I 0.95 Br 0.05 )3.

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