Perovskite film layer and solar cell

Abstract

This invention relates to the field of solar cell technology, specifically disclosing a perovskite film and a solar cell. The perovskite film is prepared using a perovskite precursor solution, which includes a perovskite precursor, a solvent, and an additive. The additive includes at least one sulfur-containing compound containing ion pairs, where X is a halogen. The hybrid perovskite additive of this invention is applied to cells containing Cs... + In the preparation process of hybrid perovskites, Cs can be effectively avoided. + It can mitigate interface defects caused by aggregation at the interface and regulate the crystallization of hybrid perovskites, avoiding the introduction of Br into the hybrid perovskite. ‑ The formation of impurity phases that are easily caused can lead to the formation of a high-quality perovskite film. After the perovskite film is annealed, the substances remaining in the bulk phase can still passivate bulk defects and regulate crystallization without affecting device stability, thereby improving device efficiency and stability.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and more particularly to a perovskite film and a solar cell. Background Technology

[0002] Perovskites are a class of materials with a crystal structure of ABX3, in which the A-site ion is usually an organic cation or Cs. + In perovskite, the B-site ion is typically a metal ion, and the X-site ion is typically a halide ion. Mixed halide-mixed cation hybrid perovskite (hereinafter referred to as hybrid perovskite) refers to perovskite materials where the X-site ion is composed of multiple halogens and the A-site ion is composed of multiple cations. Due to their wide tunable bandgap and good stability, hybrid perovskites are very suitable for wide bandgap and tandem perovskite solar cells.

[0003] For hybrid perovskites, the crystallization of these perovskite films plays a decisive role in carrier recombination, phase separation, and long-term stability. Therefore, the regulation of hybrid perovskite film crystallization is particularly important. Compared to single-cation or single-halogen perovskites, the crystallization of hybrid perovskites is much more difficult to control.

[0004] When Br is present in a mixed halogen - At that time, Br - The higher the content of halogenated ...

[0005] Furthermore, the inventors discovered that when Cs is introduced into the mixed cations of hybrid perovskites... + At this time, interface defects are easily caused, which intensifies charge recombination and affects device performance. MACl and DMACl, however, are effective against the introduction of Cs. + The resulting interface defects have not been significantly improved, so there are still many defects in the interface. Summary of the Invention

[0006] The purpose of this invention is to provide a perovskite film and a solar cell in light of the existing technology.

[0007] In the perovskite film preparation process of the present invention, a perovskite precursor solution containing... Sulfur-containing compounds with ion pairs, which are applied to compounds containing Cs + In the preparation process of hybrid perovskites, Cs can be effectively avoided. + It can mitigate interface defects caused by aggregation at the interface and regulate the crystallization of hybrid perovskites, avoiding the introduction of Br into the hybrid perovskite. - The formation of impurity phases that are easily caused can lead to the formation of high-quality perovskite films. After the perovskite film is annealed, the substances remaining in the bulk phase can still passivate bulk defects and regulate crystallization without affecting device stability, thereby improving device efficiency and stability.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] First, the present invention provides a perovskite film layer prepared using a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor, a solvent, and an additive, wherein the additive comprises at least one containing... A sulfur-containing compound with ion pairs, wherein X is a halogen.

[0010] The perovskite film of the present invention is prepared using a perovskite precursor solution containing a hybrid perovskite additive. The perovskite precursor solution is then infused with an additive containing... Sulfur-containing compounds with ion pairs, and applications of sulfur-containing compounds containing Cs. + In the preparation of hybrid perovskites, sulfur-containing compounds can form hydrogen bonds with organic cations in the hybrid perovskite, passivating cation vacancy defects in the bulk phase of the hybrid perovskite and reducing vacancy defects, while also reducing the ion migration of organic cations. Simultaneously, through the coordination interaction between sulfur-containing compounds and the hybrid perovskite, the formation energy of the intermediate phase is lowered, allowing Cs... + It transforms into a more stable intermediate phase, thereby avoiding Cs + Clustering at the interface effectively avoids Cs + Interface defects caused by aggregation at the interface can be addressed by combining the synergistic effects of these two factors to regulate the crystallization of hybrid perovskites and avoid the introduction of Br into the hybrid perovskites. - The formation of impurity phases that are easily caused can lead to the formation of high-quality perovskite films. After the perovskite film is annealed, the substances remaining in the bulk phase can still passivate bulk defects and regulate crystallization without affecting device stability, thereby improving device efficiency and stability.

[0011] In some embodiments, the sulfur-containing compound has the following general structural formula I:

[0012]

[0013] Wherein, R1 and R2 are each independently a substituted or unsubstituted alkyl group;

[0014] X and X' are each halogens independently.

[0015] In some embodiments, the halogen is any one of Cl, Br, and I.

[0016] In some embodiments, the alkyl group has 1 to 4 carbon atoms.

[0017] In some embodiments, the sulfur-containing compound is a compound represented by Formula II:

[0018]

[0019] In some embodiments, the perovskite precursor includes at least one first perovskite precursor containing B-site ions and X-site ions from the perovskite material, and at least one second perovskite precursor containing A-site ions and X-site ions from the perovskite material.

[0020] In some embodiments, the perovskite precursor includes at least one A-site ion of type Cs. + The second perovskite precursor, and at least one second perovskite precursor in which the A-site ion is an organic cation;

[0021] And / or, the perovskite precursor includes at least one X-site ion of Br. - The first or second perovskite precursor, and at least one X-site ion other than Br - The first or second perovskite precursor of a halide anion other than that.

[0022] In some embodiments, the step of preparing the perovskite precursor solution includes:

[0023] Prepare a perovskite precursor solution containing the sulfur-containing compound;

[0024] The perovskite precursor solution is used to form a film.

[0025] Second, the present invention provides a solar cell comprising the perovskite film layer described above.

[0026] In some embodiments, the solar cell includes a bottom electrode, an electron transport layer, the perovskite film layer, a hole transport layer, and a top electrode arranged sequentially along its thickness direction;

[0027] Alternatively, the battery may include a bottom electrode, the hole transport layer, the perovskite film layer, the electron transport layer, and the top electrode arranged sequentially along the thickness direction of the battery. Attached Figure Description

[0028] Figure 1This is a flowchart of the method for preparing the sulfur-containing compound of the present invention.

[0029] Figure 2 This is a flowchart of a method for preparing a perovskite film according to the present invention.

[0030] Figure 3 This is a flowchart of another method for preparing the perovskite film of the present invention.

[0031] Figure 4 This is a schematic diagram of the upright structure of the solar cell of the present invention.

[0032] Figure 5 This is a schematic diagram of the inverted structure solar cell of the present invention.

[0033] Figure 6 This is a flowchart of a method for preparing a perovskite film according to an embodiment of the present invention.

[0034] Figure 7 This is a flowchart of the preparation method of the perovskite film in Comparative Example 1.

[0035] Figure 8 This is a flowchart of the preparation method of the perovskite film in Comparative Example 2.

[0036] Figure 9 This is a flowchart of the preparation method of the perovskite film in Comparative Example 3.

[0037] In the picture:

[0038] Bottom electrode 1; electron transport layer 2; perovskite film layer 3; hole transport layer 4; top electrode 5. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0040] First, this invention discloses a perovskite film layer prepared using a perovskite precursor solution. The perovskite precursor solution includes a perovskite precursor, a solvent, and additives. The additives include at least one component containing... A sulfur-containing compound with ion pairs, where X is a halogen.

[0041] The inventors discovered that when Cs is introduced into the mixed cations of hybrid perovskites... +The reason why interface defects are easily caused is that the Cs of the mixed cations at the A-site of the hybrid perovskite are... + It is easy for these substances to accumulate and accumulate at the interface, which can lead to interface defects.

[0042] In the perovskite film preparation process of the present invention, a perovskite precursor solution containing... Sulfur-containing compounds with ion pairs, and applications of sulfur-containing compounds containing Cs. + In the preparation of hybrid perovskites, sulfur-containing compounds can form hydrogen bonds with organic cations in the hybrid perovskite, passivating cation vacancy defects in the bulk phase of the hybrid perovskite and reducing vacancy defects, while also reducing the ion migration of organic cations. Simultaneously, through the coordination interaction between sulfur-containing compounds and the hybrid perovskite, the formation energy of the intermediate phase is lowered, allowing Cs... + It transforms into a more stable intermediate phase, thereby avoiding Cs + Clustering at the interface effectively avoids Cs + Interface defects caused by aggregation at the interface can be addressed by combining the synergistic effects of these two factors to regulate the crystallization of hybrid perovskites and avoid the introduction of Br into the hybrid perovskites. - The formation of impurity phases that are easily caused can lead to the formation of high-quality perovskite films. After the perovskite film is annealed, the substances remaining in the bulk phase can still passivate bulk defects and regulate crystallization without affecting device stability, thereby improving device efficiency and stability.

[0043] In some embodiments, the preferred structural formula of the sulfur-containing compound is shown in Formula I below:

[0044]

[0045] Wherein, R1 and R2 are each independently a substituted or unsubstituted alkyl group;

[0046] X and X' are each halogens independently.

[0047] Understandably, substituted alkyl refers to one or more hydrogen atoms on an alkyl group being replaced by other atoms or groups, while unsubstituted alkyl refers to an alkyl group without other atoms or groups replacing hydrogen atoms on it. Independently, this means that in the same sulfur-containing compound, X and X' can be the same halogen or different halogens.

[0048] In some embodiments, preferably, R1 and R2 are alkyl groups of the same type, and X and X' are halogens of the same type, which can reduce the difficulty of producing high-purity hybrid perovskite additives, and make it easier to adjust the amount of hybrid perovskite additives used in hybrid perovskites as needed.

[0049] Experiments have shown that the sulfur-containing compound represented by Formula I not only has a strong ability to form hydrogen bonds with organic cations, but also a strong ability to form bonds with Cs. + The ability to form coordination, applied to compounds containing Cs + In the preparation process of hybrid perovskites, it is possible to effectively avoid the influence of Cs. + Interface defects caused by aggregation at the interface should be avoided, and the introduction of Br into hybrid perovskites should be prevented. - The formation of impurity phases is easily caused by this, and after the perovskite film is annealed, the DSA (DSA is an abbreviation, and the general formula is shown below) remaining in the bulk phase can still passivate bulk phase defects and regulate crystallization, without affecting the stability of the device.

[0050]

[0051] In some embodiments, the halogen is any one of Cl, Br, I, and F.

[0052] In some embodiments, preferably, the halogen is any one of Cl, Br, and I.

[0053] In some embodiments, more preferably, the halogen is Cl.

[0054] In some embodiments, the alkyl group has 1 to 4 carbon atoms.

[0055] For example, the alkyl group has 1, 2, 3 or 4 carbon atoms, but is not limited to this.

[0056] In some embodiments, see Figure 1 As shown, the preparation method of the sulfur-containing compound of formula I includes the following steps:

[0057] S100. Thio-bis(alkylphthalimide) is hydrolyzed under alkaline conditions, followed by acidification, to form a thioorganic intermediate:

[0058]

[0059] For example, an alkaline environment can be provided by sodium hydroxide, and the reaction temperature is about 50°C to 90°C. Under alkaline conditions, the amide bond of thio-bis(alkylphthalimide) is hydrolyzed, the nitrogen-carbon bond is broken, and then acidification is carried out at low temperature to form a thioorganic intermediate. For example, it can be acidified with HCl.

[0060] S200. Thio-organic intermediates react with hydrohalic acids to form sulfur-containing compounds:

[0061]

[0062] For example, the reaction temperature is 20℃~80℃.

[0063] In some embodiments, thio-bis(alkylphthalimide) can be generated by the thiolation reaction of N-(bromoalkyl)phthalimide with Na2S2.

[0064] In some embodiments, more preferably, the sulfur-containing compound is the compound represented by Formula II:

[0065]

[0066] The sulfur-containing compound shown in Formula II not only has a strong ability to form hydrogen bonds with organic cations, but also a strong ability to form bonds with Cs. + The ability to form coordination compounds, along with the more stable sulfur-containing compounds, makes it suitable for applications containing Cs. + In the preparation process of hybrid perovskites, it is possible to effectively avoid the influence of Cs. + Interface defects caused by aggregation at the interface should be avoided, and the introduction of Br into hybrid perovskites should be prevented. - The DSA can passivate bulk defects and regulate crystallization after the perovskite film is annealed, without affecting the stability of the device.

[0067] For example, the synthetic route for the sulfur-containing compound represented by Formula II is as follows:

[0068]

[0069] The synthesis process is simple and conducive to industrial production.

[0070] In some embodiments, the perovskite precursor includes at least one first perovskite precursor containing B-site ions and X-site ions of the perovskite material and at least one second perovskite precursor containing A-site ions and X-site ions of the perovskite material, to form a perovskite material with the general formula ABX3.

[0071] In some embodiments, the perovskite precursor includes at least one A-site ion of Cs. + The second perovskite precursor, and at least one second perovskite precursor in which the A-site ion is an organic cation;

[0072] And / or, the perovskite precursor includes at least one X-site ion of Br. - The first or second perovskite precursor, and at least one X-site ion other than Br - The first or second perovskite precursor of a halide anion other than that.

[0073] That is, the perovskite material formed from the perovskite precursor in the perovskite film is a hybrid perovskite, and the A-site ions of the hybrid perovskite include Cs. + and at least one organic cation,

[0074] And / or, the X-site ion in hybrid perovskites includes Br - and at least one other than Br - Other halogen anions.

[0075] Specifically, the general formula for hybrid perovskites is ABX3, where the organic cation at the A-site can be a methylamine ion (MA). + ), formamidinium ion (FA) + ), phenylethylamine ion (PEA) + ), guanidine ion (GA) + ), ethylamine ion (EA) + At least one of the following, but not limited to: ; for example, the B-site ion may be Pb 2+ Sn 2+ Mn 2+ 、Ge 2+ At least one of them, but not limited to.

[0076] In some embodiments, the A-site ion of the hybrid perovskite may further include Rb. + La 3+ 、Sr 2+ Ba 2+ At least one of them.

[0077] In some embodiments, the step of preparing the perovskite precursor solution includes:

[0078] Prepare a perovskite precursor solution containing the sulfur-containing compound;

[0079] To form a film from the perovskite precursor solution.

[0080] In the first embodiment, see Figure 2 As shown, the method for preparing the perovskite film includes:

[0081] S11. A perovskite precursor solution containing B-site ions and X-site ions from perovskite material, a second perovskite precursor containing A-site ions and X-site ions from perovskite material, a solvent, and the above-mentioned additives are mixed to prepare a perovskite precursor solution containing sulfur-containing compounds.

[0082] S12. Apply a perovskite precursor solution containing sulfur compounds to a substrate and anneal it to obtain a perovskite film. For example, the perovskite precursor solution can be applied to the substrate by spin coating, blade coating, slot coating, spraying, inkjet printing, physical vapor deposition or chemical vapor deposition, etc., but is not limited to these methods.

[0083] The first perovskite precursor includes at least one first inorganic salt containing B-site ions and X-site ions from the perovskite material, and the second perovskite precursor includes at least one second inorganic salt containing A-site ions and X-site ions from the perovskite material, as well as at least one organic salt containing A-site ions and X-site ions from the perovskite material.

[0084] In the second implementation, see Figure 3 As shown, the method for preparing the perovskite film includes:

[0085] S21. A first inorganic salt containing B-site ions and X-site ions from perovskite material, a second inorganic salt containing A-site ions and X-site ions from perovskite material, a solvent, and the above-mentioned additives are mixed to prepare an inorganic phase precursor solution containing sulfur-containing compounds.

[0086] S22. An inorganic phase precursor solution containing a sulfur-containing compound is applied to a substrate to form an inorganic phase film layer. For example, the inorganic phase precursor solution can be applied to the substrate by spin coating, blade coating, slot coating, spraying, inkjet printing, physical vapor deposition or chemical vapor deposition, but is not limited thereto.

[0087] S23. Mix the organic salt containing A-site ions and X-site ions from the perovskite material, the solvent, and the above-mentioned additives to prepare an organic phase precursor solution containing sulfur-containing compounds;

[0088] S24. An organic phase precursor solution containing a sulfur-containing compound is applied to an inorganic phase film layer and annealed to obtain a perovskite film layer. For example, the organic phase precursor solution can be applied to the inorganic phase film layer by spin coating, blade coating, slot coating, spraying, inkjet printing, physical vapor deposition or chemical vapor deposition, but is not limited thereto.

[0089] Understandably, the substrate refers to the material on which the perovskite thin film is to be deposited. The substrate can be a single-layer material or a material composed of multiple layers. In some embodiments, the substrate, serving as the foundation of the perovskite solar cell, can be a transparent conductive substrate, typically made of materials such as fluorine-doped tin oxide (FTO) or indium-doped tin oxide (ITO), which possess high light transmittance and good conductivity. Its main function is to introduce sunlight and collect the generated current. The choice of transparent conductive substrate is crucial to the performance of the perovskite solar cell because it affects not only the incident light but also the current extraction.

[0090] Secondly, the present invention provides a solar cell comprising the perovskite film layer described above.

[0091] The solar cell in this embodiment of the invention can be configured as a nip structure or an inverted pin structure. See also Figure 4As shown, when the solar cell is in a positive orientation, the cell includes a bottom electrode 1, an electron transport layer 2 (ETL), a perovskite film layer 3, a hole transport layer 4 (HTL), and a top electrode 5 arranged sequentially along its thickness direction; see also Figure 5 As shown, when the solar cell is an inverted structure, the cell includes a bottom electrode 1, a hole transport layer 4 (HTL), a perovskite film layer 3, an electron transport layer 2 (ETL), and a top electrode arranged sequentially along its thickness direction.

[0092] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0093] Example 1

[0094] This invention provides a perovskite film prepared using a perovskite precursor solution. The perovskite precursor solution comprises a perovskite precursor, a solvent, and an additive, wherein the additive includes at least one component containing NH3. + X - A sulfur-containing compound with ion pairs, wherein X is a halogen.

[0095] In this embodiment, the general structural formula of the sulfur-containing compound is shown in Formula I below:

[0096]

[0097] In this embodiment, R1 and R2 are both CH2, and X and X' are both Cl. That is, in this embodiment, the sulfur-containing compound is the compound shown in Formula II.

[0098]

[0099] In this embodiment, see Figure 6 As shown, the method for preparing the perovskite film includes:

[0100] S10. Preparation of perovskite precursor solution containing sulfur-containing compounds:

[0101] Preparation of perovskite precursor solution: Weigh 39.8 mg of CsBr, 68.6 mg of PbBr2, 467 mg of PbI2 and 157 mg of FAI into a sample vial, add 1 ml of solvent (DMF:DMSO = 4:1), place on a hot plate at 60 °C and heat for 12 h. After the sample is completely dissolved, filter through a 0.22 μm PTFE filter membrane to obtain the perovskite precursor solution.

[0102] Add 10% M of a sulfur-containing compound to the perovskite precursor solution;

[0103] S20. To form a film from the perovskite precursor solution:

[0104] Using a pipette, 80 μl of perovskite precursor solution (containing 10% M sulfur-containing compound) was placed on the substrate. The substrate was then rotated at 1000 rpm for 10 s and 6000 rpm for 30 s. Ten seconds before the end of the spin coating, 100 μl of chlorobenzene was slowly added dropwise onto the film. The substrate was then placed on a heating stage at 150 °C and annealed in air (30%-40% humidity) for 15 min to obtain the perovskite film.

[0105] Furthermore, this embodiment discloses a solar cell comprising the perovskite film layer prepared as described above.

[0106] In this embodiment, the solar cell includes a bottom electrode, an electron transport layer (ETL), the perovskite film layer, a hole transport layer (HTL), and a top electrode arranged sequentially along the thickness direction of the cell. The bottom electrode is an ITO substrate, the electron transport layer is a SnO2 layer, the hole transport layer is a Spiro-OMeTAD (2,2',7,7'-tetra(p-methoxyaniline)-9,9'-spirodifluorene) layer, and the top electrode is an Ag layer.

[0107] Example 2

[0108] This invention provides a perovskite film prepared using a perovskite precursor solution. The perovskite precursor solution comprises a perovskite precursor, a solvent, and an additive, wherein the additive includes at least one component containing... A sulfur-containing compound with ion pairs, wherein X is a halogen.

[0109] In this embodiment, the general structural formula of the sulfur-containing compound is shown in Formula I below:

[0110]

[0111] In this embodiment, R1 and R2 are both CH2CH2, and X and X' are both Cl.

[0112] In this embodiment, see Figure 6 As shown, the method for preparing the perovskite film includes:

[0113] S10. Preparation of perovskite precursor solution containing sulfur-containing compounds:

[0114] Preparation of perovskite precursor solution: Weigh 39.8 mg of CsBr, 68.6 mg of PbBr2, 467 mg of PbI2 and 157 mg of FAI into a sample vial, add 1 ml of solvent (DMF:DMSO = 4:1), place on a hot plate at 60 °C and heat for 12 h. After the sample is completely dissolved, filter through a 0.22 μm PTFE filter membrane to obtain the perovskite precursor solution.

[0115] Add 10% M of a sulfur-containing compound to the perovskite precursor solution;

[0116] S20. To form a film from the perovskite precursor solution:

[0117] Using a pipette, 80 μl of perovskite precursor solution (containing 10% M sulfur-containing compound) was placed on the substrate. The substrate was then rotated at 1000 rpm for 10 s and 6000 rpm for 30 s. Ten seconds before the end of the spin coating, 100 μl of chlorobenzene was slowly added dropwise onto the film. The substrate was then placed on a heating stage at 150 °C and annealed in air (30%-40% humidity) for 15 min to obtain the perovskite film.

[0118] Furthermore, this embodiment discloses a solar cell comprising the perovskite film layer prepared as described above.

[0119] In this embodiment, the solar cell includes a bottom electrode, an electron transport layer (ETL), the perovskite film layer, a hole transport layer (HTL), and a top electrode arranged sequentially along the thickness direction of the cell. The bottom electrode is an ITO substrate, the electron transport layer is a SnO2 layer, the hole transport layer is a Spiro-OMeTAD (2,2',7,7'-tetra(p-methoxyaniline)-9,9'-spirodifluorene) layer, and the top electrode is an Ag layer.

[0120] Comparative Example 1

[0121] The difference between this comparative example and Example 1 is that the additive in the perovskite precursor solution of this comparative example is MACl.

[0122] See Figure 7 As shown, the method for preparing the perovskite film in this comparative example includes:

[0123] S101. Preparation of perovskite precursor solution containing MACl:

[0124] Preparation of perovskite precursor solution: Weigh 39.8 mg of CsBr, 68.6 mg of PbBr2, 467 mg of PbI2 and 157 mg of FAI into a sample vial, add 1 ml of solvent (DMF:DMSO = 4:1), place on a hot plate at 60 °C and heat for 12 h. After the sample is completely dissolved, filter through a 0.22 μm PTFE filter membrane to obtain the perovskite precursor solution.

[0125] Add 10% M MACl to the perovskite precursor solution;

[0126] S201. To form a film from the perovskite precursor solution:

[0127] Using a pipette, 80 μl of the perovskite precursor solution (with 10% M MACl added) was placed on the substrate. The substrate was then rotated at 1000 rpm for 10 s and 6000 rpm for 30 s. Ten seconds before the end of the spin coating, 100 μl of chlorobenzene was slowly added dropwise onto the film. The substrate was then placed on a heating stage at 150 °C and annealed in air (30%-40% humidity) for 15 min to obtain the perovskite film.

[0128] Furthermore, this comparative example discloses a solar cell comprising the perovskite film layer prepared as described above.

[0129] In this comparative example, the solar cell includes a bottom electrode, an electron transport layer (ETL), the aforementioned perovskite film layer, a hole transport layer (HTL), and a top electrode arranged sequentially along the thickness direction of the cell. The bottom electrode is an ITO substrate, the electron transport layer is a SnO2 layer, the hole transport layer is a Spiro-OMeTAD (2,2',7,7'-tetra(p-methoxyaniline)-9,9'-spirodifluorene) layer, and the top electrode is an Ag layer.

[0130] Comparative Example 2

[0131] The difference between this comparative example and Example 1 is that the additive in the perovskite precursor solution of this comparative example is dimethyl sulfide.

[0132] See Figure 8 As shown, the method for preparing the perovskite film in this comparative example includes:

[0133] S102. Preparation of perovskite precursor solution containing dimethyl sulfide:

[0134] Preparation of perovskite precursor solution: Weigh 39.8 mg of CsBr, 68.6 mg of PbBr2, 467 mg of PbI2 and 157 mg of FAI into a sample vial, add 1 ml of solvent (DMF:DMSO = 4:1), place on a hot plate at 60 °C and heat for 12 h. After the sample is completely dissolved, filter through a 0.22 μm PTFE filter membrane to obtain the perovskite precursor solution.

[0135] Add 10% M dimethyl sulfide to the perovskite precursor solution;

[0136] S202. To form a film from the perovskite precursor solution:

[0137] Using a pipette, 80 μl of perovskite precursor solution (containing 10% M dimethyl sulfide) was placed on the substrate. The substrate was then rotated at 1000 rpm for 10 s and 6000 rpm for 30 s. Ten seconds before the end of the spin coating, 100 μl of chlorobenzene was slowly added dropwise onto the film. The substrate was then placed on a heating stage at 150 °C and annealed in air (30%-40% humidity) for 15 min to obtain the perovskite film.

[0138] Furthermore, this comparative example discloses a solar cell comprising the perovskite film layer prepared as described above.

[0139] In this comparative example, the solar cell includes a bottom electrode, an electron transport layer (ETL), the aforementioned perovskite film layer, a hole transport layer (HTL), and a top electrode arranged sequentially along the thickness direction of the cell. The bottom electrode is an ITO substrate, the electron transport layer is a SnO2 layer, the hole transport layer is a Spiro-OMeTAD (2,2',7,7'-tetra(p-methoxyaniline)-9,9'-spirodifluorene) layer, and the top electrode is an Ag layer.

[0140] Comparative Example 3

[0141] The difference between this comparative example and Example 1 is that no additional additives are added to the perovskite precursor solution during the preparation of the perovskite film in this comparative example.

[0142] For details, see Figure 9 As shown, the method for preparing the perovskite film in this comparative example includes:

[0143] S103. Preparation of additive-free perovskite precursor solution:

[0144] Preparation of perovskite precursor solution: Weigh 39.8 mg of CsBr, 68.6 mg of PbBr2, 467 mg of PbI2 and 157 mg of FAI into a sample vial, add 1 ml of solvent (DMF:DMSO = 4:1), place on a hot plate at 60 °C and heat for 12 h. After the sample is completely dissolved, filter through a 0.22 μm PTFE filter membrane to obtain the perovskite precursor solution.

[0145] S203. To form a film from the perovskite precursor solution:

[0146] Using a pipette, 80 μl of the perovskite precursor solution was placed on the substrate. The solution was then rotated at 1000 rpm for 10 s and 6000 rpm for 30 s. Ten seconds before the end of the spin coating, 100 μl of chlorobenzene was slowly added dropwise onto the film. The substrate was then placed on a heating stage at 150 °C and annealed in air (30%-40% humidity) for 15 min to obtain the perovskite film.

[0147] Furthermore, this comparative example discloses a solar cell comprising the perovskite film layer prepared as described above.

[0148] In this comparative example, the solar cell includes a bottom electrode, an electron transport layer (ETL), the aforementioned perovskite film layer, a hole transport layer (HTL), and a top electrode arranged sequentially along the thickness direction of the cell. The bottom electrode is an ITO substrate, the electron transport layer is a SnO2 layer, the hole transport layer is a Spiro-OMeTAD (2,2',7,7'-tetra(p-methoxyaniline)-9,9'-spirodifluorene) layer, and the top electrode is an Ag layer.

[0149] Performance testing:

[0150] 1) Electrical performance testing:

[0151] Batteries prepared in each experimental group of Examples 1 to 2 and Comparative Examples 1 to 3 were subjected to electrical performance tests.

[0152] 2) Stability test:

[0153] Batteries prepared in each experimental group of Examples 1-2 and Comparative Examples 1-3 were placed in a high-temperature environment for testing. The decay rate of the final conversion efficiency relative to the initial conversion efficiency was obtained after 1000 hours. The decay rate = (initial conversion efficiency - final conversion efficiency) × 100% / initial conversion efficiency. The smaller the decay rate, the better the stability.

[0154]

[0155] Experimental results show that, compared with Comparative Examples 1 to 3, Examples 1 to 2 of the present invention have higher conversion efficiency and better stability. Using the sulfur-containing compound of the present invention as a hybrid perovskite additive can effectively improve the conversion efficiency and enhance the stability of the device.

[0156] In the description of this specification, references to terms such as "some embodiments," "exemplary," "example," or "for example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0157] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A perovskite film, characterized in that, It is prepared using a perovskite precursor solution, wherein the perovskite precursor solution comprises a perovskite precursor, a solvent, and an additive, wherein the additive comprises at least one containing... A sulfur-containing compound with ion pairs, wherein X is a halogen.

2. The perovskite film layer according to claim 1, characterized in that, The general structural formula of the sulfur-containing compound is shown in Formula I below: Wherein, R1 and R2 are each independently a substituted or unsubstituted alkyl group; X and X' are each halogens independently.

3. The perovskite film layer according to claim 2, characterized in that, The halogen is any one of Cl, Br, and I.

4. The perovskite film layer according to claim 2, characterized in that, The alkyl group has 1 to 4 carbon atoms.

5. The perovskite film layer according to claim 2, characterized in that, The sulfur-containing compound is the compound represented by Formula II:

6. The perovskite film layer according to claim 1, characterized in that, The perovskite precursor includes at least one first perovskite precursor containing B-site ions and X-site ions from the perovskite material, and at least one second perovskite precursor containing A-site ions and X-site ions from the perovskite material.

7. A perovskite film layer according to claim 6, characterized in that, The perovskite precursor includes at least one A-site ion of Cs. + The second perovskite precursor, and at least one second perovskite precursor in which the A-site ion is an organic cation; And / or, the perovskite precursor includes at least one X-site ion of Br. - The first or second perovskite precursor, and at least one X-site ion other than Br - The first or second perovskite precursor of a halide anion other than that.

8. The perovskite film layer according to claim 1, characterized in that, The step of preparing the perovskite precursor solution includes: Prepare a perovskite precursor solution containing the sulfur-containing compound; The perovskite precursor solution is used to form a film.

9. A solar cell, characterized in that, Includes the perovskite film layer according to any one of claims 1 to 8.

10. The solar cell according to claim 9, characterized in that, The solar cell includes a bottom electrode, an electron transport layer, the perovskite film layer, a hole transport layer, and a top electrode arranged sequentially along its thickness direction. Alternatively, the battery may include a bottom electrode, the hole transport layer, the perovskite film layer, the electron transport layer, and the top electrode arranged sequentially along the thickness direction of the battery.

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