Perovskite thin film, solar cell prepared by in-situ chemical reaction of cation at site and preparation method thereof
Patent Information
- Application Number
- CN202311416830.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-28
- Publication Date
- 2026-09-25
- Estimated Expiration
- 2043-10-28
AI Technical Summary
其次制备的钙钛矿薄膜为多晶薄膜，晶粒变大、晶界随之会减少，导致电子-空穴非辐射复合的缺陷态密度会降低，器件性能可以得到大幅提升；反之晶粒越小、晶界越多，薄膜内缺陷态密度越高，从而导致严重的电子-空穴非辐射复合而限制器件性能的提升
[0025]本发明通过在制备钙钛矿薄膜的过程中，在钙钛矿前驱体溶液中加入少量异氰酸添加剂，该添加剂可与钙钛矿A位阳离子原位作用而形成中间体，中间体的形成可改变晶粒生长动力学过程，调节钙钛矿晶粒生长过程中成核与晶粒生长之间的动力学关系，制备出晶粒大、晶界少的高质量钙钛矿薄膜。可以锚定钙钛矿薄膜的A位阳离子，同时钝化未配位的Pb2+，从而降低钙钛矿薄膜内部缺陷，稳定钙钛矿结构，退火完成高质量钙钛矿薄膜的制备，组装高效太阳能电池器件。调节前驱体中异氰酸添加剂的含量，从而有效提高钙钛矿太阳电池的器件效率。通过本发明提供的制备方法所获得的钙钛矿薄膜质量高、重复性好，有望在钙钛矿太阳电池、钙钛矿发光二极管、钙钛矿光探测器、钙钛矿激光等光电半导体器件领域获得广泛应用。
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Figure CN117545329B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of perovskite technology, specifically to a perovskite thin film prepared by in-situ chemical reaction of A-site cations, a solar cell, and a method for preparing the same. Background Technology
[0002] Organic-inorganic halide perovskite materials possess excellent properties such as high light absorption coefficient, long carrier lifetime, tunable bandgap, and solution processability, making them promising candidates for application in optoelectronic research fields such as solar cells, transistors, and X-ray detectors. Organic-inorganic hybrid perovskite materials have already achieved a photoelectric conversion efficiency of 26% in the photovoltaic field and are highly likely to replace silicon-based cells as the dominant technology in the future.
[0003] The efficiency of perovskite solar cells largely depends on defects in the perovskite thin film. Firstly, defects such as free radicals (FAs) exist during the fabrication of the perovskite thin film. + Vacancies and uncoordinated Pb 2+ Defects, etc. Secondly, the perovskite thin film prepared is a polycrystalline thin film. As the grains become larger, the grain boundaries decrease, which leads to a decrease in the defect state density of nonradiative electron-hole recombination, and the device performance can be greatly improved. Conversely, the smaller the grains and the more grain boundaries, the higher the defect state density in the thin film, which leads to severe nonradiative electron-hole recombination and limits the improvement of device performance. Summary of the Invention
[0004] To address the shortcomings of the aforementioned background technology, this invention primarily utilizes in-situ chemical reactions to anchor FA ions and passivate Pb. 2+ To prepare high-efficiency perovskite thin films and solar cells.
[0005] This invention provides an in-situ chemical reaction method for preparing high-efficiency perovskite thin films and solar cells using A-site cations. The method uses isocyanate as an additive. During the reaction, an intermediate is formed that anchors the A-site cations in the perovskite thin film while passivating uncoordinated Pb. 2+ This reduces internal defects in the perovskite film, and annealing completes the preparation of a high-quality perovskite film, enabling the assembly of high-efficiency solar cell devices.
[0006] The first objective of this invention is to provide a method for preparing perovskite thin films by in-situ chemical reaction of A-site cations, comprising the following steps:
[0007] Prepare a perovskite precursor solution;
[0008] Isocyanate is added to the perovskite precursor solution, and the reaction solution is obtained by in-situ chemical reaction between isocyanate and the A-site cation of the precursor.
[0009] The reaction solution is coated onto a substrate and then annealed by heating to obtain a perovskite thin film on the substrate.
[0010] Preferably, the isocyanate has the following structural formula:
[0011]
[0012] The amount of isocyanate added is 0.5%-15% of the volume of the perovskite precursor solvent.
[0013] Preferably, the heating and annealing process is carried out at an annealing temperature of 100-150°C and an annealing time of 10-60 minutes.
[0014] Preferably, the solute in the perovskite precursor solution includes lead-based compounds and halogen compounds;
[0015] The lead-based compound is one or more of PbI2, PbCl2, PbBr2, and Pb(SCN)2;
[0016] The chemical formula of the halogen compound is AX, wherein A is one or more of methylamine, formamidinium, and cesium, and X is one or more of F, Cl, Br, and I.
[0017] Preferably, the solvent in the perovskite precursor solution is one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethyl carbonate, γ-butyrolactone (GBL), acetone, toluene, chlorobenzene, chloroform, methanol, ethanol, isopropanol, diethyl ether, acetonitrile, anisole, ethyl acetate, and pyridine.
[0018] The molar concentration of the perovskite precursor solution is 0.1-1.5 mol / mL.
[0019] Preferably, the perovskite thin film preparation process is carried out in a dry nitrogen glove box environment with a water oxygen value of less than 0.01 ppm, and the coating is applied by one or more of spin coating, blade coating, and spray coating.
[0020] The second objective of this invention is to provide a perovskite thin film.
[0021] The third objective of this invention is to provide a perovskite solar cell, which, from bottom to top, comprises a glass substrate, a bottom electrode layer, a bottom charge transport layer, the aforementioned perovskite thin film layer, a top charge transport layer, and a top electrode layer.
[0022] Preferably, the bottom electrode layer and the top electrode layer are one or more of the following: ITO transparent electrode, FTO transparent electrode, silver / gold nanowire / oxide mixed transparent electrode, oxide (ZnO, In2O3) / metal (silver) / oxide (ZnO, In2O3) multi-level transparent electrode, silver / gold electrode, and carbon material electrode; wherein, at least one of the bottom electrode layer and the top electrode layer is a transparent electrode.
[0023] Preferably, the bottom charge transport layer and the top charge transport layer are one or more of the following: titanium dioxide, zinc oxide, tin dioxide, nickel oxide, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, fullerene, fullerene derivative, 2,2′,7,7′-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9′-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanodimethyl-p-benzoquinone.
[0024] Compared with the prior art, the beneficial effects of the present invention are:
[0025] This invention involves adding a small amount of isocyanate to the perovskite precursor solution during the preparation of perovskite thin films. This additive can interact in situ with the A-site cations of perovskite to form an intermediate. The formation of this intermediate alters the grain growth kinetics, regulating the kinetic relationship between nucleation and grain growth during perovskite grain growth, thus producing high-quality perovskite thin films with large grains and few grain boundaries. It can also anchor the A-site cations in the perovskite thin film while passivating uncoordinated Pb. 2+ This process reduces internal defects in the perovskite thin film, stabilizes the perovskite structure, and annealing completes the preparation of a high-quality perovskite thin film, enabling the assembly of high-efficiency solar cell devices. Adjusting the isocyanate additive content in the precursor effectively improves the device efficiency of the perovskite solar cell. The perovskite thin film obtained by the preparation method provided by this invention is of high quality and has good reproducibility, and is expected to be widely used in the fields of perovskite solar cells, perovskite light-emitting diodes, perovskite photodetectors, perovskite lasers, and other optoelectronic semiconductor devices.
[0026] Through the isocyanate additive engineering in this invention, the formation of intermediates can change the crystallization kinetics of perovskite, thereby reducing the energy barrier that needs to be overcome in the crystal growth process, and annealing completes the preparation of high-quality perovskite thin films.
[0027] The perovskite films prepared by this invention have larger grains. After perovskite film formation, additives remain inside the film, and self-polymerizing networks can form within the additives, passivating uncoordinated Pb. 2+ It inhibits the formation of iodine vacancies, stabilizes the perovskite structure, and reduces the defect state density;
[0028] Perovskite solar cells fabricated using additive engineering exhibit good repeatability, higher photoelectric conversion efficiency, and better device performance stability. Attached Figure Description
[0029] Figure 1 A comparative schematic diagram of perovskite thin film preparation processes with and without isocyanate additives;
[0030] Figure 2 Schematic diagram of a perovskite solar cell device;
[0031] Figure 3 NMR spectrum of the in-situ reaction between isocyanate and A-site FAI;
[0032] Figure 4 Infrared spectrum of the in-situ reaction between isocyanate and FAI at the A site;
[0033] Figure 5 Scanning electron microscope (SEM) images of the surface (a) and cross-section (b) of the perovskite thin film layer prepared without additives;
[0034] Figure 6 Scanning electron microscope (SEM) images of the surface (a) and cross-section (b) of the perovskite thin film layer prepared with 0.5% isocyanate.
[0035] Figure 7 Scanning electron microscope (SEM) images of the surface (a) and cross-section (b) of the perovskite thin film layer prepared with 1.0% isocyanate.
[0036] Figure 8 Scanning electron microscope (SEM) images of the surface (a) and cross-section (b) of the perovskite thin film layer prepared with 2.0% isocyanate;
[0037] Figure 9 Current density-voltage scan curve of perovskite solar cell device prepared without additives;
[0038] Figure 10 Current density-voltage scan curve of perovskite solar cell device prepared with 0.5% isocyanate;
[0039] Figure 11 Current density-voltage scan curve of perovskite solar cell device prepared with 1.0% isocyanate;
[0040] Figure 12 Current density-voltage scan curve of perovskite solar cell device prepared by adding 2.0% isocyanate. Detailed Implementation
[0041] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.
[0042] Currently, the main methods for reducing the defect state density of perovskite thin films include: controlling the composition of the perovskite precursor to strengthen the bonding force between crystals; controlling the crystallization process during perovskite film preparation to effectively regulate the kinetic relationship between nucleation and grain growth, appropriately reducing the number of nuclei and extending the grain production time. Among these, the most effective method is to introduce functional additives into the perovskite thin film to prepare highly efficient and stable perovskite solar cells.
[0043] The first aspect of this invention provides a method for preparing perovskite thin films by in-situ chemical reaction of A-site cations, comprising the following steps:
[0044] Prepare a perovskite precursor solution;
[0045] Isocyanate is added to the perovskite precursor solution, and the reaction solution is obtained by in-situ chemical reaction between isocyanate and the A-site cation of the precursor.
[0046] The reaction solution is coated onto a substrate and then annealed by heating to obtain a perovskite thin film on the substrate.
[0047] This invention utilizes isocyanate additives to form intermediates that alter the crystallization kinetics of perovskite, thereby lowering the energy barrier required to overcome during crystal growth and annealing to prepare high-quality perovskite films. The perovskite films prepared by this invention have larger grains, and the additives remain inside the film after perovskite formation, simultaneously passivating uncoordinated Pb. 2+ This reduces internal defects in the perovskite film, and annealing completes the preparation of a high-quality perovskite film, enabling the assembly of high-efficiency solar cell devices.
[0048] This invention uses isocyanate as an additive in order to reveal the in-situ reaction between the isocyanate additive and the A-site cation, such as... Figure 3 Characterization was performed using NMR and IR spectroscopy. The two chemical shifts of FAI were at 7.85 and 8.81 ppm, corresponding to FA... + The -CH and =NH vibrations on the cation. The chemical shift of isocyanate is at 8.54 ppm. When isocyanate is mixed with FAI and reacted in situ, two new peaks appeared at 9.0 and 8.65 ppm, corresponding to the structure after the in-situ addition of isocyanate and FAI. Figure 4 Infrared spectroscopy also confirmed the formation of a new NCN stretching vibration corresponding to the structure following the in-situ reaction of isocyanate with the A-site FA cation. A specific embodiment was developed to verify the impact of the reaction with the A-site cation on the performance of the perovskite solar cell.
[0049] In one embodiment, the perovskite thin film preparation method includes the following process: Figure 1 As shown, it includes:
[0050] First, a perovskite precursor of a certain composition is prepared and dissolved uniformly. Then, 0.5%-15% of isocyanate additive is added to it in an amount equal to the volume of the precursor, and the mixture is stirred overnight for later use.
[0051] The prepared solution is spin-coated onto the substrate and heated and annealed to form a perovskite film. The annealing temperature is 100-150℃ and the time is 10-60min.
[0052] The isocyanate has the following structural formula:
[0053]
[0054] The amount of isocyanate added is 0.5%-15% of the volume of the perovskite precursor solvent.
[0055] According to the present invention, the heating and annealing process is generally carried out at an annealing temperature of 100-150°C and an annealing time of 10-60 minutes.
[0056] Specifically, the solutes in the perovskite precursor solution include lead-based compounds and halogen compounds;
[0057] The lead-based compound is one or more of PbI2, PbCl2, PbBr2, and Pb(SCN)2;
[0058] The chemical formula of the halogen compound is AX, wherein A is one or more of methylamine, formamidinium, and cesium, and X is one or more of F, Cl, Br, and I.
[0059] The solvent in the perovskite precursor solution is one or more of the following: N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethyl carbonate, γ-butyrolactone (GBL), acetone, toluene, chlorobenzene, chloroform, methanol, ethanol, isopropanol, diethyl ether, acetonitrile, anisole, ethyl acetate, and pyridine.
[0060] The molar concentration of the perovskite precursor solution is 0.1-1.5 mol / mL.
[0061] According to the present invention, the perovskite thin film preparation process is carried out in a dry nitrogen glove box environment with a water oxygen value of less than 0.01 ppm, and the coating is prepared by one or more of spin coating, blade coating, and spray coating.
[0062] A second aspect of the present invention provides a perovskite thin film.
[0063] A third aspect of the present invention provides a perovskite solar cell, participating in... Figure 2 As shown, from bottom to top, it includes a glass substrate (1), a bottom electrode layer (2), a bottom charge transport layer (3), the perovskite thin film layer (4) mentioned above, a top charge transport layer (5) and a top electrode layer (6);
[0064] The bottom electrode layer (2) is placed on the upper surface of the glass substrate (1) and directly contacts the unconnected layer; the perovskite thin film layer (4) is above the bottom electrode layer (2) and connected in the middle by the bottom charge transport layer (3); the top charge transport layer (5) and the top electrode layer (6) are placed on the upper side of the perovskite thin film layer (4); at least one side of the bottom electrode layer (2) and the top electrode layer (6) is transparent.
[0065] Specifically, the bottom electrode layer (2) and the top electrode layer (6) are one or more of the following: ITO transparent electrode, FTO transparent electrode, silver / gold nanowire / oxide mixed transparent electrode, oxide (ZnO In2O3) / metal (silver) / oxide (ZnO In2O3) multi-level transparent electrode, silver / gold electrode, and carbon material electrode; wherein, at least one of the bottom electrode layer (2) and the top electrode layer (6) is a transparent electrode.
[0066] The bottom charge transport layer (3) and the top charge transport layer (5) are respectively one or more of the following: titanium dioxide, zinc oxide, zinc tin oxide, tin dioxide, nickel oxide, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, fullerene, fullerene derivative, 2,2′,7,7′-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9′-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanodimethyl-p-benzoquinone.
[0067] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.
[0068] Example 1
[0069] A high-efficiency perovskite solar cell was prepared by an in-situ chemical reaction between an isocyanate additive and an A-site cation. For example... Figure 2As shown, the structure of this battery includes: a glass substrate, a bottom electrode layer (transparent electrode FTO), a bottom charge transport layer (tin oxide), a perovskite layer (FA-based), a top charge transport layer (2,2′,7,7′-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9′-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), and a top electrode layer (silver). The perovskite thin film layer is prepared using the following method:
[0070] 1. Preparation of perovskite precursor solution: Weigh 705.3 mg of PbI2, 240.76 mg of MAI, 33.76 mg of MACl, and 8.23 mg of MAPbBr3 in a glove box and dissolve them in a mixed solvent of 889 μL DMF and 111 μL LDMSO. Stir overnight at room temperature. Add small molecule isocyanate as an additive. The total amount of additive is 0.5% of the total volume of the precursor solvent.
[0071] 2. Preparation of perovskite thin film: An appropriate amount of perovskite precursor solution was dropped onto a glass substrate and spin-coated for 10 seconds at a speed of 1000 rpm with an acceleration of 2000 rpm; then spin-coated for 30 seconds at a speed of 5000 rpm with an acceleration of 2000 rpm, and 600 μL of anhydrous diethyl ether was added as a reverse solvent at the 10th second. After spin-coating, the sample was annealed at 100℃ for 60 minutes to form a photoactive perovskite thin film. The surface morphology and cross-sectional morphology of the prepared perovskite thin film are shown in the figure. Figure 6 As shown, the average grain size is 600 nm, which is comparable to a perovskite thin film prepared under the same conditions without additives. (See [reference needed]). Figure 5 As shown, the grain size has increased significantly compared to the previous year. The cross-sectional scanning electron microscope image shows that the grains grow perpendicular to the substrate and throughout the entire film. The preparation of the perovskite film was carried out in a dry nitrogen glove box, with water and oxygen content both less than 0.01 ppm.
[0072] Test characterization: The battery was tested at AM 1.5G, 100mW / cm². 2 The current density-voltage (JV) performance curve of the battery was tested under illumination, as shown in the figure. Figure 10 As shown, the short-circuit current density of the battery is 25.48 mA / cm². 2 The open-circuit voltage is 1.16V, the fill factor is 81.52%, and the photoelectric conversion efficiency is 24.08%. Compared with a perovskite solar cell without additives under the same conditions, see [reference needed]. Figure 9 As shown, the performance in all aspects is significantly improved. The main reasons are the increase in the grain size of the perovskite thin film, the decrease in the nonradiative recombination degree of charge carriers in the film, and the passivation of perovskite film defects by the in-situ reaction of isocyanate additives with A-site cations, thus stabilizing the perovskite structure.
[0073] Example 2
[0074] This embodiment provides a method for preparing high-efficiency perovskite solar cells based on an in-situ chemical reaction between isocyanate additives and A-site cations. For example... Figure 2 As shown, the structure of this battery includes: a glass substrate, a bottom electrode layer (transparent electrode FTO), a bottom charge transport layer (tin oxide), a perovskite layer (FA-based), a top charge transport layer (Spiro-OMeTAD), and a top electrode layer (silver). The fabrication method of the perovskite thin film layer is as follows:
[0075] 1. Preparation of perovskite precursor solution: Weigh 705.3 mg of PbI2, 240.76 mg of MAI, 33.76 mg of MACl, and 8.23 mg of MAPbBr3 in a glove box and dissolve them in a mixed solvent of 889 μL DMF and 111 μL LDMSO. Stir overnight at room temperature. Add small molecule isocyanate as an additive. The total amount of additive is 1.0% of the total volume of the precursor solvent.
[0076] 2. Preparation of perovskite thin film: An appropriate amount of perovskite precursor solution was dropped onto a glass substrate and spin-coated for 10 seconds at a speed of 1000 rpm with an acceleration of 2000 rpm; then spin-coated for 30 seconds at a speed of 5000 rpm with an acceleration of 2000 rpm. At the 10th second, 600 μL of anhydrous diethyl ether was added as an antisolvent. After spin-coating, the sample was annealed at 100℃ for 60 minutes to form a photoactive perovskite thin film. The surface morphology and cross-sectional morphology of the prepared perovskite thin film are shown below. Figure 7 As shown, the average grain size is 500 nm, which is similar to that of a perovskite thin film prepared under the same conditions without additives. Figure 5 Compared to the significant increase in individual grain size, the perovskite film surface is rough. The perovskite film was prepared in a dry nitrogen glove box with water and oxygen content less than 0.01 ppm.
[0077] Test characterization: The battery was tested at AM 1.5G, 100mW / cm². 2 The current density-voltage (JV) performance curve of the battery was tested under illumination, as shown in the figure. Figure 11 As shown, the short-circuit current density of the battery is 24.87 mA / cm². 2 The open-circuit voltage is 1.15V, the fill factor is 79.81%, and the photoelectric conversion efficiency is 22.92%, which is comparable to that of a perovskite solar cell without additives under the same conditions (such as...). Figure 9 Compared to the previous version, the performance in all aspects is significantly improved, mainly due to the increased grain size of the perovskite film layer, the reduced non-radiative recombination of charge carriers within the film, and the in-situ passivation of perovskite film defects by isocyanate additives, thus stabilizing the perovskite structure. However, the in-situ reaction with the precursor may be too vigorous, resulting in a rough film surface.
[0078] Example 3
[0079] This embodiment provides a method for preparing high-efficiency perovskite solar cells based on an in-situ chemical reaction between isocyanate additives and A-site cations. For example... Figure 2 As shown, the structure of this battery includes: a glass substrate, a bottom electrode layer (transparent electrode FTO), a bottom charge transport layer (tin oxide), a perovskite layer (FA-based), a top charge transport layer (Spiro-OMeTAD), and a top electrode layer (silver). The fabrication method of the perovskite thin film layer is as follows:
[0080] 1. Preparation of perovskite precursor solution: Weigh 705.3 mg of PbI2, 240.76 mg of MAI, 33.76 mg of MACl, and 8.23 mg of MAPbBr3 in a glove box and dissolve them in a mixed solvent of 889 μL DMF and 111 μL LDMSO. Stir overnight at room temperature. Add small molecule isocyanate as an additive. The total amount of the additive is 2.0% of the total volume of the precursor solvent.
[0081] 2. Preparation of perovskite thin film: An appropriate amount of perovskite precursor solution was dropped onto a glass substrate and spin-coated for 10 seconds at a speed of 1000 rpm with an acceleration of 2000 rpm; then spin-coated for 30 seconds at a speed of 5000 rpm with an acceleration of 2000 rpm, and 600 μL of diethyl ether antisolvent was added at the 10th second. After spin-coating, the sample was annealed at 100℃ for 60 minutes to form a photoactive phase perovskite thin film. The surface morphology and cross-sectional morphology of the prepared perovskite thin film are shown below. Figure 8 As shown, the average grain size is 500 nm, which is similar to that of a perovskite thin film prepared under the same conditions without additives. Figure 5 Compared to the previous method, the grain size did not change much, but the surface of the film was uneven. The perovskite film was prepared in a dry nitrogen glove box with water and oxygen content of less than 0.01 ppm.
[0082] Test characterization: The battery was tested at AM 1.5G, 100mW / cm². 2 The current density-voltage (JV) performance curve of the battery was tested under illumination, as shown in the figure. Figure 12 As shown, the short-circuit current density of the battery is 24.93 mA / cm². 2 The open-circuit voltage is 1.14V, the fill factor is 71.21%, and the photoelectric conversion efficiency is 20.23%, which is comparable to that of a perovskite solar cell without additives under the same conditions (such as...). Figure 9Compared to the previous method, the performance is almost the same. The main reason is that the grain size of the perovskite film layer remains basically unchanged. The in-situ passivation of isocyanate leads to an increase in open circuit voltage. However, excessive addition results in a violent reaction with the precursor, leading to a rough film surface morphology and large contact defects at the interface with the transport layer, resulting in a significant loss of filler factor.
[0083] This invention describes preferred embodiments and their effects. However, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to include both the preferred embodiments and all changes and modifications falling within the scope of this invention.
[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing perovskite thin films by in-situ chemical reaction of A-site cations, characterized in that, Includes the following steps: Prepare a perovskite precursor solution; Isocyanate is added to the perovskite precursor solution, and the reaction solution is obtained by in-situ chemical reaction between isocyanate and the A-site cation of the precursor. The reaction solution is coated onto a substrate and then annealed by heating to obtain a perovskite thin film on the substrate. The A-site cation is FA. + .
2. The method for preparing perovskite thin films by in-situ chemical reaction at the A-site cation according to claim 1, characterized in that, The isocyanate has the following structural formula: ； The amount of isocyanate added is 0.5%-15% of the volume of the perovskite precursor solvent.
3. The method for preparing perovskite thin films by in-situ chemical reaction at the A-site cation according to claim 1, characterized in that, During the heating and annealing process, the annealing temperature is 100-150 ℃ and the annealing time is 10-60 minutes.
4. The method for preparing perovskite thin films by in-situ chemical reaction of A-site cations according to claim 1, characterized in that, The solutes in the perovskite precursor solution include lead-based compounds and halogen compounds; The lead-based compound is one or more of PbI2, PbCl2, PbBr2, and Pb(SCN)2; The chemical formula of the halogen compound is AX, where A is formamidin and X is one or more of F, Cl, Br, and I.
5. The method for preparing perovskite thin films by in-situ chemical reaction of A-site cations according to claim 1, characterized in that, The solvent in the perovskite precursor solution is one or more of the following: N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethyl carbonate, γ-butyrolactone (GBL), acetone, toluene, chlorobenzene, chloroform, methanol, ethanol, isopropanol, diethyl ether, acetonitrile, anisole, ethyl acetate, and pyridine.
6. The method for preparing perovskite thin films by in-situ chemical reaction of A-site cations according to claim 1, characterized in that, The perovskite thin film is prepared in a dry nitrogen glove box environment with a water and oxygen value of less than 0.01 ppm. The coating is prepared by one or more of spin coating, blade coating, and spray coating.
7. A perovskite thin film prepared by the method according to any one of claims 1 to 6.
8. A perovskite solar cell, characterized in that, From bottom to top, it includes a glass substrate (1), a bottom electrode layer (2), a bottom charge transport layer (3), a perovskite thin film layer (4) as described in claim 7, a top charge transport layer (5), and a top electrode layer (6).
9. The perovskite solar cell according to claim 8, characterized in that, The bottom electrode layer (2) and the top electrode layer (6) are one or more of the following: ITO transparent electrode, FTO transparent electrode, silver / gold nanowire / oxide mixed transparent electrode, oxide / metal / oxide multi-level structure transparent electrode, silver / gold electrode, and carbon material electrode; wherein, at least one of the bottom electrode layer (2) and the top electrode layer (6) is a transparent electrode.
10. The perovskite solar cell according to claim 8, characterized in that, The bottom charge transport layer (3) and the top charge transport layer (5) are respectively one or more of the following: titanium dioxide, zinc oxide, zinc tin oxide, tin dioxide, nickel oxide, poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, fullerene, fullerene derivative, 2,2′,7,7′-tetra[N,N-di(4-methoxyphenyl)amino]-9,9′-spirodifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and 2,3,5,6-tetrafluoro-7,7′,8,8′-tetracyanodimethyl-p-benzoquinone.