Lead complexes, precursor solution for preparing perovskite, perovskite layer, perovskite solar cell, method for preparing the same and use thereof

Abstract

This invention discloses lead complexes, precursor solutions for preparing perovskites, perovskite layers, perovskite solar cells, batteries, their preparation methods, and applications. The lead complex has the general structural formula PbI₂·0.5La, where La is a ligand, and the structure of the ligand La is as follows: where R is selected from -(CH₂). n - Where n is 1-8. This invention addresses the issues of numerous micropores, uneven film texture, and poor stability in CsPbI3 perovskites by providing a novel lead complex (1D PbI2·0.5La) and introducing 1D PbI2·0.5La into the perovskite precursor solution to prepare CsPbI3 thin films. The introduction of the 1D structure improves the photoelectric performance of the device, passivates surface defects, reduces carrier recombination, and improves device stability, providing guidance for the industrialization of CsPbI3-based perovskite solar cells.

Description

Technical Field

[0001] This invention relates to the technical field of photovoltaic solar cells, and more specifically, to lead complexes, precursor solutions for preparing perovskites, perovskite layers, perovskite solar cells, cells, their preparation methods, and applications. Background Technology

[0002] Over the past decade, the photoelectric conversion efficiency (PCE) of organic-inorganic hybrid perovskite solar cells has increased to 25.7%.

[0003] However, the thermal stability of organic-inorganic hybrid perovskites is affected by the presence of volatile organic amine components in their structure, and they are strong acid-weak base salts, easily decomposing under strongly alkaline conditions. Replacing the A-site ammonium ions in the octahedral framework of perovskite with inorganic Cs components can help. + A perovskite structure with an all-inorganic CsPbI3 composition can be obtained. The all-inorganic CsPbI3 perovskite structure has attracted much attention due to its superior thermal stability and more matched energy levels when used as a series structure for silicon-based solar cells.

[0004] The preparation process of CsPbI3 typically involves using DMAI, which has a high decomposition temperature, as a stabilizer to first form DMAPbI3, followed by high-temperature annealing to remove DMAI, while Cs... + The film formed by entering the crystal lattice to form CsPbI3 often has many micropores, is uneven, and has a high defect state density, resulting in low open-circuit voltage and poor stability of the device.

[0005] Therefore, it is necessary to address the problem of numerous uneven micropores in existing CsPbI3 perovskite films. Summary of the Invention

[0006] To address the problems in existing technologies, this invention proposes a lead complex, a precursor solution for perovskite preparation, a perovskite layer, a perovskite solar cell, a battery, and its preparation method and applications. This invention addresses the issues of numerous micropores, uneven film surface, and poor stability in CsPbI3 perovskites by providing a novel lead complex (1D PbI2·0.5La, where 1D refers to one-dimensionality) and introducing 1D PbI2·0.5La into the perovskite precursor solution to prepare CsPbI3 thin films. The introduction of the 1D structure improves the photoelectric performance of the device, passivates surface defects, reduces carrier recombination, and improves device stability, providing guidance for the industrialization of CsPbI3-based perovskite solar cells.

[0007] One objective of this invention is to provide a lead complex with the general structural formula PbI₂·0.5La, wherein La is a ligand, and the structure of the ligand La is as follows:

[0008]

[0009] Wherein, R is selected from -(CH2). n - where n is 1-8;

[0010] The coordination structure of the lead complex is shown below:

[0011]

[0012] In the lead complex described in this invention, preferably,

[0013] The ligand La is selected from one of 1,2-bis([2,2'-bipyridine]-6-yloxy)ethane, 1,3-bis([2,2'-bipyridine]-6-yloxy)propane, 1,4-bis([2,2'-bipyridine]-6-yloxy)butane, 1,5-bis([2,2'-bipyridine]-6-yloxy)pentane, 1,6-bis([2,2'-bipyridine]-6-yloxy)hexane, 1,7-bis([2,2'-bipyridine]-6-yloxy)heptane, and 1,8-bis([2,2'-bipyridine]-6-yloxy)octane.

[0014] A second objective of this invention is to provide a method for preparing lead complexes as described in one objective of this invention, wherein a PbI2 solution and a La ligand solution are mixed and allowed to stand, and the resulting yellow crystals are the lead complexes.

[0015] In the method for preparing the lead complex according to the present invention, preferably,

[0016] The PbI2 solution and the La ligand solution are optionally filtered through a filter membrane before being mixed.

[0017] The concentration of the PbI2 solution is 0.1–0.5 mmol / mL;

[0018] The concentration of the La ligand solution is 0.1–0.5 mmol / mL;

[0019] The volume ratio of the PbI2 solution to the La ligand solution is 1:1 to 1:5;

[0020] The PbI2 solution and the La ligand solution use the same solvent, which is selected from at least one of DMF, DMSO and NMP.

[0021] When mixing the PbI2 solution and the La ligand solution, shake rapidly for 5-10 seconds.

[0022] The resting time is 1 to 3 days.

[0023] In the method for preparing the lead complex described in this invention, most preferably,

[0024] Dissolve PbI₂ (230.5 mg, 0.5 mmol) in 1 ml of DMF and stir until completely dissolved; this solution is labeled as solution A. Dissolve La (96 mg, 0.25 mmol) in 2 ml of DMF and stir until completely dissolved; this solution is labeled as solution B. Filter all solutions A through a 0.22 μm filter membrane into a 5 ml glass bottle. Then, quickly filter all solutions B into the same bottle. Shake rapidly for 5 seconds and let stand for 3 days. Yellow PbI₂·0.5La crystals will precipitate. Filter the obtained crystals, wash three times with diethyl ether, and dry before storage.

[0025] A third objective of this invention is to provide a precursor solution for preparing perovskite, the precursor solution comprising PbI2, CsI, dimethylammonium hydroiodate, lead complex and solvent;

[0026] The lead complex is selected from the lead complex described in one of the objectives of this invention or the lead complex prepared by the method described in another objective of this invention.

[0027] In the precursor solution for preparing perovskite according to the present invention, preferably,

[0028] In the precursor solution

[0029] The concentration of PbI2 is 0.6–1.0 mol / L; and / or,

[0030] The concentration of CsI is 0.6–1.0 mol / L; and / or,

[0031] The concentration of dimethylammonium hydroiodate is 0.6–1.0 mol / L; and / or,

[0032] The concentration of the lead complex is 0.2–2 mg / mL; and / or,

[0033] The solvent is at least one of DMF or DMSO.

[0034] The fourth objective of this invention is to provide a perovskite layer comprising a CsPbI3 layer and a lead complex; the lead complex is distributed at the grain boundaries and surface of the CsPbI3 layer.

[0035] Preferably, it is prepared from the precursor liquid described in the third objective of this invention.

[0036] The fifth objective of this invention is to provide a method for preparing a perovskite layer, wherein the precursor liquid described in the third objective of this invention is loaded onto a substrate and then annealed to obtain the perovskite layer.

[0037] Preferably used for the preparation of the perovskite layer described in the fourth objective of this invention.

[0038] In the method for preparing the perovskite layer described in this invention, preferably,

[0039] The thickness of the perovskite layer is 250–350 nm; and / or,

[0040] The loading method is spin coating; and / or,

[0041] The annealing temperature is 160–220°C; and / or,

[0042] The annealing time is 10–60 min; and / or,

[0043] The volume of the precursor solution used is 30–100 μL; and / or,

[0044] Preferably, the spin coating speed is 2000-4000 rpm and the time is 20-40 s.

[0045] The sixth objective of this invention is to provide a perovskite solar cell, wherein the perovskite solar cell comprises the perovskite layer described in the fourth objective of this invention or the perovskite layer prepared by the method described in the fifth objective of this invention.

[0046] In the perovskite solar cell of the present invention, preferably,

[0047] The perovskite solar cell includes a bottom electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a top electrode.

[0048] Preferably,

[0049] The bottom electrode is FTO conductive glass; and / or,

[0050] The electron transport layer is a TiO2 layer; and / or,

[0051] The hole transport layer is Spiro-OMeTAD or copper phthalocyanine; and / or,

[0052] The top electrode is made of gold or silver;

[0053] More preferably,

[0054] The sheet resistance of FTO conductive glass is 5–30 Ω, and the transmittance is 80–99%; and / or,

[0055] The area of ​​the bottom electrode is 1–9 cm². 2 ; and / or,

[0056] The electron transport layer thickness is 10–50 nm; and / or,

[0057] The hole transport layer thickness is 150–200 nm; and / or,

[0058] The thickness of the top electrode is 50–150 nm.

[0059] The seventh objective of this invention is to provide a method for preparing a perovskite solar cell as described in the sixth objective of this invention, comprising the following steps:

[0060] Fabrication of the electron transport layer:

[0061] The spin coating solution of the electron transport layer was spin-coated onto the bottom electrode, annealed, cooled, and then subjected to plasma cleaning to obtain the bottom electrode / electron transport layer.

[0062] Preparation of the perovskite layer:

[0063] The precursor liquid was spin-coated onto the electron transport layer and annealed to obtain the bottom electrode / electron transport layer / perovskite layer.

[0064] Fabrication of the hole transport layer:

[0065] Spiro-OMeTAD spin coating solution is spin-coated onto the perovskite layer, or copper phthalocyanine is vacuum-deposited onto the perovskite layer to obtain the bottom electrode / electron transport layer / perovskite layer / hole transport layer.

[0066] Fabrication of the top electrode:

[0067] The top electrode is prepared by vacuum evaporation of the bottom electrode / electron transport layer / perovskite layer / hole transport layer, or by coating the bottom electrode / electron transport layer / perovskite layer / hole transport layer with conductive carbon paste to prepare the top electrode; thus obtaining the perovskite solar cell.

[0068] In the method for preparing perovskite solar cells according to the present invention, preferably,

[0069] During the fabrication of the electron transport layer,

[0070] The spin coating solution for the electron transport layer is a TiO2 spin coating solution, preferably composed of: 1.5 mL ethanol or isopropanol, 15 μL concentrated hydrochloric acid, and 50–150 μL tetraisopropyl titanate or tetrabutyl titanate.

[0071] During annealing, first anneal at 100-150℃ for 5-30 minutes, then anneal at 450-550℃ for 30-100 minutes;

[0072] The plasma cleaning process takes 3–10 minutes; and / or,

[0073] The spin coating speed is 3000-6000 rpm, and the time is 20-40 s.

[0074] In the method for preparing a perovskite solar cell according to the present invention, preferably, Spiro-OMeTAD spin-coating solution is spin-coated onto the perovskite layer to prepare the hole transport layer.

[0075] The hole transport layer spin-coating solution contains 70–110 mg Spiro-OMeTAD, 10–30 μL of lithium bis(trifluoromethanesulfonyl)imide solution, 10–40 μL of FK209 solution, and 20–50 μL of 4-tert-butylpyridine per milliliter of solvent; and / or,

[0076] The solvent in the spin-coating solution for the hole transport layer is at least one of chlorobenzene and chloroform.

[0077] Preferably, the lithium bis(trifluoromethanesulfonyl)imide solution is an acetonitrile solution with a concentration of 520 mg / mL, and the FK209 solution is an acetonitrile solution with a concentration of 300 mg / mL; and / or,

[0078] Spin coating speed is 2000–4000 rpm, time is 20–40 s; and / or,

[0079] When copper phthalocyanine is deposited onto a perovskite layer by vacuum evaporation, the vacuum level is less than 7 × 10⁻⁶. -4 Pa, evaporation current is 50-80A;

[0080] During the fabrication of the top electrode, the vacuum degree of the vacuum evaporation process is lower than 7 × 10⁻⁶. -4 Pa.

[0081] The eighth objective of this invention is to provide an application of a perovskite solar cell prepared as described in the sixth objective of this invention or as described in the seventh objective of this invention in photovoltaic power generation.

[0082] Compared with the prior art, the present invention has at least the following advantages:

[0083] This invention provides a novel lead complex; by introducing a 1D structure PbI2·0.5La into the precursor solution for perovskite preparation, this invention effectively improves the photoelectric performance of the device, enhances the surface morphology of the CsPbI3 perovskite film, and improves the overall stability.

[0084] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein. Attached Figure Description

[0085] Figure 1 This is a schematic diagram of the fabricated perovskite solar cell structure;

[0086] Figure 2 These are surface electron microscope (SEM) images of Example 1 and Comparative Example 1 before and after the introduction of PbI2·0.5La. The left image is the surface SEM image of Comparative Example 1 without the addition of PbI2·0.5La, and the right image is the surface SEM image of Example 1 after the addition of PbI2·0.5La.

[0087] Figure 3 The figures show the XRD patterns before and after the introduction of PbI2·0.5La in the embodiments. The lower curve in the figure is the XRD pattern of Comparative Example 1 without the addition of PbI2·0.5La, and the upper curve in the figure is the XRD pattern of Example 1 after the addition of PbI2·0.5La.

[0088] Figure 4 These are the current-voltage test curves of the solar cells prepared in Examples 1-3;

[0089] Figure 5 The stability test curves of the perovskite solar cells prepared in Example 1 are shown.

[0090] Figure 6 This is the XRD pattern of PbI2·0.5La powder.

[0091] Explanation of reference numerals in the attached figures:

[0092] In this design, 1 is the bottom electrode, 2 is the electron transport layer, 3 is the perovskite layer, 4 is the hole transport layer, and 5 is the top electrode. Detailed Implementation

[0093] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0094] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0095] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0096] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0097] Preparation Example 1

[0098] The ligand La is 1,3-bis([2,2'-bipyridine]-6-yloxy)propane, and its synthesis method is as follows:

[0099] Synthesis steps: Under nitrogen protection, 360 μL of 1,3-propanediol and 0.48 g of 60% sodium hydride were dissolved in 30 mL of anhydrous DMF, and the reaction was carried out at 80 °C for 4 hours. Then, 2.35 g of 6-bromo-2,2'-bipyridine was added, and the reaction continued for another 6 hours. After the reaction was completed, the temperature was cooled to room temperature, and a large amount of water was added, resulting in the precipitation of a yellow powder. The powder was filtered, repeatedly washed with water, and dried. The product was purified using a silica gel column chromatography with dichloromethane / ethyl acetate (V / V = 10:1) as the mobile phase. Finally, the solvent was removed by rotary evaporation, yielding 1.18 g of the product, with a yield of 62%.

[0100] The NMR data for 1,3-bis([2,2'-bipyridine]-6-yloxy)propane are as follows: 1 H NMR (CDCl3, 500MHz): 8.65 (d, J = 4.0Hz, 2H), 8.37 (d, J = 7.8Hz, 2H), 8.01 (d, J = 7.3Hz, 2H), 7.76 (t, J = 12.2, 7.8Hz, 2H), 7.70 (t, J = 12 .0,7.6Hz,2H),7.27(t,J=15.0,7.5Hz,2H),6.79(d,J=8.0Hz,2H),4.67(t,J=11.8,5.8Hz,4H),2.40(m,2H).Mass spectrum (Q-TOF) m / z[La+Na] + Theoretical value: 407.1484; Measured value: 407.0619.

[0101] The synthesized ligand La(1,3-bis([2,2'-bipyridine]-6-yloxy)propane) was used to prepare lead complexes, and the specific steps are as follows:

[0102] PbI₂ (230.5 mg, 0.5 mmol) was dissolved in 1 ml of DMF and stirred until completely dissolved; this solution is labeled as solution A. La (96 mg, 0.25 mmol) was dissolved in 2 ml of DMF and stirred until completely dissolved; this solution is labeled as solution B. All solutions of A were filtered through a 0.22 μm filter into a 5 ml glass bottle. Subsequently, all solutions of B were also quickly filtered into the same bottle. After shaking rapidly for 5 seconds, the mixture was allowed to stand for 3 days, at which point yellow PbI₂·0.5La crystals precipitated. The obtained crystals were filtered, washed three times with diethyl ether, dried, and then stored. The XRD pattern of the obtained lead complex PbI₂·0.5La powder is shown below. Figure 6 As shown.

[0103] Preparation Example 2

[0104] The ligand La is 1,5-bis([2,2'-bipyridine]-6-yloxy)pentane, and its synthesis method is as follows:

[0105] Synthesis steps: Under argon protection, 520 mg of 1,5-pentanediol and 0.48 g of 60% sodium hydride were dissolved in 30 mL of anhydrous DMF, and the mixture was reacted at 80 °C for 4 hours. Then, 2.35 g of 6-bromo-2,2'-bipyridine was added, and the reaction continued for another 6 hours. After the reaction was complete, the temperature was cooled to room temperature, and a large amount of water was added, resulting in the precipitation of a yellow powder. The powder was filtered, repeatedly washed with water, and dried. The product was purified using a silica gel column chromatography with dichloromethane / ethyl acetate (V / V = 10:1) as the mobile phase. Finally, the solvent was removed by rotary evaporation, yielding 1.28 g of the product, with a yield of 62%.

[0106] Mass spectrometry (Q-TOF) m / z of 1,5-bis([2,2'-bipyridine]-6-yloxy)pentane [La+Na] + Theoretical value: 435.1797; Measured value: 435.0152.

[0107] The synthesized ligand La(1,5-bis([2,2'-bipyridine]-6-yloxy)pentane) was used to prepare lead complexes, and the specific steps are as follows:

[0108] Dissolve PbI₂ (230.5 mg, 0.5 mmol) in 1 ml of DMF and stir until completely dissolved; this solution is labeled as solution A. Dissolve La (103.5 mg, 0.25 mmol) in 3 ml of DMF and stir until completely dissolved; this solution is labeled as solution B. Filter all solutions A through a 0.22 μm filter membrane into a 5 ml glass bottle. Then, quickly filter all solutions B into the same bottle. Shake rapidly for 10 seconds and let stand for 1 day. Yellow PbI₂·0.5La crystals will precipitate. Filter the obtained crystals, wash three times with diethyl ether, and dry before storage.

[0109] Preparation Example 3

[0110] The ligand La is 1,8-bis([2,2'-bipyridine]-6-yloxy)octane, and its synthesis method is as follows:

[0111] Synthesis steps: Under argon protection, 725 mg of 1,8-octanediol and 0.48 g of 60% sodium hydride were dissolved in 30 mL of anhydrous DMF, and the reaction was carried out at 80 °C for 4 hours. Then, 2.35 g of 6-bromo-2,2'-bipyridine was added, and the reaction continued for another 6 hours. After the reaction was completed, the temperature was cooled to room temperature, and a large amount of water was added, resulting in the precipitation of a yellow powder. The powder was filtered, repeatedly washed with water, and dried. The product was purified using a silica gel column chromatography with dichloromethane / ethyl acetate (V / V = 10:1) as the mobile phase. Finally, the solvent was removed by rotary evaporation, yielding 1.25 g of the product, with a yield of 55%.

[0112] Mass spectra (Q-TOF) m / z of 1,8-bis([2,2'-bipyridine]-6-yloxy)octane [La+Na] + Theoretical value: 477.2266; Measured value: 477.0148.

[0113] The synthesized ligand La(1,8-bis([2,2'-bipyridine]-6-yloxy)octane) was used to prepare lead complexes, and the specific steps are as follows:

[0114] Dissolve PbI₂ (230.5 mg, 0.5 mmol) in 1 mL of DMF and stir until completely dissolved; this solution is labeled as solution A. Dissolve La (113.5 mg, 0.25 mmol) in 5 mL of DMF and stir until completely dissolved; this solution is labeled as solution B. Filter all solutions A through a 0.22 μm filter membrane into a 10 mL glass bottle. Then, quickly filter all solutions B into the same bottle. Shake rapidly for 10 seconds and let stand for 2 days. Yellow PbI₂·0.5La crystals will precipitate. Filter the obtained crystals, wash three times with diethyl ether, and dry before storage.

[0115] Example 1

[0116] Step (1) Cleaning of the conductive glass:

[0117] The substrate was ultrasonically treated with dish soap, deionized water, acetone and isopropanol for 20 minutes each, then dried with a hair dryer and treated with a plasma cleaner for 3 minutes.

[0118] Step (2) Fabrication of the electron transport layer:

[0119] 100 μL of tetraisopropyl titanate and 15 μL of concentrated hydrochloric acid were added to 1.5 mL of ethanol and stirred for 30 min. Then, the mixture was spin-coated onto the substrate from step (1) at 5000 rpm for 30 s using a spin coater to obtain a TiO2 layer. After removing the solvent, the layer was annealed at 120 °C for 10 min and then annealed at 500 °C for 40 min. After cooling, the layer was treated with a plasma cleaner for 3 min.

[0120] Step (3) Preparation of the perovskite layer:

[0121] The prepared perovskite spin coating solution was spin coated on the TiO2 deposited in (2) for 30s at a speed of 3000 rpm using a spin coater. After annealing, a 3D perovskite layer with a thickness of about 300 nm was obtained. The annealing temperature was 180℃ and the time was 8 min.

[0122] The precursor solution consisted of 0.7 M PbI2, 0.7 M CsI, 0.7 M dimethylammonium hydroiodide (DMAI), and 1 mg / mL PbI2·0.5La (the lead complex prepared in Preparation Example 1); the volume of the precursor solution used was 60 μL.

[0123] Step (4) Preparation of the hole transport layer:

[0124] The prepared Spiro-OMeTAD solution was spin-coated onto the surface of the perovskite film prepared in step (3) to obtain a hole transport layer with a thickness of about 180 nm. The volume of the Spiro-OMeTAD solution was 30 μL, the rotation speed was 3000 rpm, and the time was 30 s.

[0125] The solvent for the hole transport layer spin coating solution is chlorobenzene, and each milliliter of chlorobenzene contains Spiro-OMeTAD 72.3 mg, lithium bis(trifluoromethanesulfonyl)imide 17.5 μL, FK209 (tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris[bis(trifluoromethane)sulfonylimide]) 29 μL, and 4-tert-butylpyridine 28.8 μL;

[0126] Of the above additives, lithium bis(trifluoromethanesulfonyl)imide is an acetonitrile solution with a concentration of 520 mg / mL, and FK209 is an acetonitrile solution with a concentration of 300 mg / mL.

[0127] Step (5) Fabrication of the metal top electrode:

[0128] The prepared substrate was placed in a vacuum evaporation apparatus, silver particles were added, and the vacuum level was below 7 × 10⁻⁶. -4 Pa, evaporation rate controlled at The resulting silver electrode thickness was approximately 100 nm. The fabricated perovskite solar cell is designated 3D / 1D / Spiro. The performance test results of the fabricated cell are shown in Table 1.

[0129] A schematic diagram of the battery structure prepared in the above embodiments is shown below. Figure 1 As shown. It includes a bottom electrode 1 (here, a conductive FTO), an electron transport layer 2 (here, a TiO2 electron transport layer), a perovskite layer 3, a hole transport layer 4 (here, a Spiro-OMeTAD hole transport layer), and a top electrode 5 (here, a silver electrode).

[0130] Comparative Example 1

[0131] It uses essentially the same preparation method as Example 1, the only difference being that...

[0132] In step (3), PbI2·0.5La was not added during the preparation of the perovskite layer. The prepared perovskite solar cell is designated as 3D / Spiro. The test results of the prepared cell performance are shown in Table 1.

[0133] Comparative Example 2

[0134] It uses essentially the same preparation method as Example 1, the only difference being that...

[0135] Without preparing the Spiro-OMeTAD hole transport layer, conductive carbon was directly coated onto the surface of the perovskite film prepared in step (3) by scraping, and then annealed at 100°C for 10 min. This yielded a carbon-based CsPbI3 perovskite device without the HTM (Spiro-OMeTAD hole transport layer). The fabricated perovskite solar cell is designated 3D / 1D / C. The performance test results of the fabricated cell are shown in Table 1.

[0136] Example 2

[0137] It uses essentially the same preparation method as Example 1, the only difference being that...

[0138] Copper phthalocyanine was deposited on the surface of the perovskite film prepared in step (3) by vacuum evaporation at a deposition rate of [missing information]. Around 30-60 nm thick hole transport layer was obtained.

[0139] Conductive carbon was coated onto the surface of the perovskite film prepared in step (3) by a scraping method, and then annealed at 100°C for 10 min. The prepared perovskite solar cell is designated as 3D / 1D / CuPc / C. The test results of the prepared cell performance are shown in Table 1.

[0140] Example 3

[0141] It uses essentially the same preparation method as Example 1, the only difference being that...

[0142] The PbI₂·0.5La used was the lead complex prepared in Preparation Example 2. The test results of the prepared battery performance are shown in Table 1.

[0143] Example 4

[0144] The preparation method used was basically the same as that in Example 1, except that the PbI2·0.5La used was the lead complex prepared in Example 3. The test results of the battery performance are shown in Table 1.

[0145] The test results of the battery performance of Embodiment 1, Embodiment 2, Comparative Example 1, and Comparative Example 2 of the present invention are as follows: Figure 4 As shown in Table 1.

[0146] Table 1

[0147]

[0148] A comparison of the results of Example 1 and Comparative Example 1 shows that the method of introducing 1D PbI2·0.5La into the perovskite precursor solution in this invention improves the CsPbI3 thin film. The introduction of the 1D structure improves the photoelectric performance of the device, passivates surface defects, reduces carrier recombination, and improves the stability of the device. Furthermore, this invention… Figure 2 The surface electron microscope images before and after the introduction of PbI2·0.5La also show that the introduction of 1D PbI2·0.5La passivates the surface defects of the CsPbI3 film. Figure 3 The XRD patterns before and after the introduction of PbI2·0.5La show that a few DMAPbI3 peaks were observed in the spectrum before the addition of 1D PbI2·0.5La, indicating that DMAI was not completely removed. After the addition, these peaks disappeared, and the peaks of 1D PbI2·0.5La were observed. Therefore, the introduction of 1D PbI2·0.5La structure in this invention effectively improves the photoelectric performance of the device, improves the surface morphology, and enhances the overall stability.

[0149] By comparing the results of Example 1, Comparative Example 1, and Comparative Example 2, the performance of the 3D / 1D / Spiro battery prepared in Example 1 is significantly higher than that of the undoped PbI2·0.5La basic device.

[0150] In addition, the stability test curve of the perovskite solar cell prepared in Example 1 is as follows: Figure 5 As shown, Figure 5In the figure, the control group refers to the perovskite solar cell prepared in Comparative Example 1. As can be seen from the figure, the method of introducing 1D PbI2·0.5La into the perovskite precursor solution to prepare CsPbI3 thin films was successful. The introduction of the 1D structure improved the photoelectric performance of the device, passivated surface defects, reduced carrier recombination, and improved device stability, providing guidance for the industrialization of CsPbI3-based perovskite solar cells.

[0151] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0152] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0153] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application’s filing, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0154] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

Claims

1. A lead complex, characterized in that: a general structure of the lead complex is PbI 2 ·0.5La, wherein La is a ligand, and a structure of the ligand La is as follows: wherein R is selected from -(CH2) n - and n is 1-8; a coordination structure of the lead complex is as follows: 2.The lead complex of claim 1, characterized in that: the ligand La is selected from one of 1,2-bis ([2,2'-bipyridine]-6-yloxy) ethane, 1,3-bis ([2,2'-bipyridine]-6-yloxy) propane, 1,4-bis ([2,2'-bipyridine]-6-yloxy) butane, 1,5-bis ([2,2'-bipyridine]-6-yloxy) pentane, 1,6-bis ([2,2'-bipyridine]-6-yloxy) hexane, 1,7-bis ([2,2'-bipyridine]-6-yloxy) heptane, and 1,8-bis ([2,2'-bipyridine]-6-yloxy) octane. 3.A method for preparing the lead complex of any one of claims 1-2, characterized in that: a PbI 2 solution and a ligand La solution are mixed and then left to stand, and yellow crystals precipitated are the lead complex. 4.The method for preparing the lead complex of claim 3, characterized in that: the PbI 2 solution and the ligand La solution are optionally filtered with a filter membrane before being mixed; a concentration of the PbI 2 solution is 0.1-0.5 mmol / mL; a concentration of the ligand La solution is 0.1-0.5 mmol / mL; a volume ratio of the PbI 2 solution to the ligand La solution is 1:1-1:5; the PbI 2 solution and the ligand La solution use the same solvent selected from at least one of DMF, DMSO, and NMP; the PbI 2 solution and the ligand La solution are quickly shaken for 5-10 s when being mixed; a standing time is 1-3 days. 5.A precursor solution for preparing a perovskite, characterized in that: the precursor solution comprises PbI 2, CsI, methylammonium iodide, a lead complex, and a solvent; the lead complex is selected from the lead complex of any one of claims 1-2 or the lead complex prepared by the method of any one of claims 3-4. 6.The precursor solution for preparing a perovskite of claim 5, characterized in that: in the precursor solution, a concentration of the PbI 2 is 0.6-1.0 mol / L; and / or, a concentration of the CsI is 0.6-1.0 mol / L; and / or, a concentration of the methylammonium iodide is 0.6-1.0 mol / L; and / or, a concentration of the lead complex is 0.2-2 mg / mL; and / or, the solvent is at least one of DMF or DMSO. 7.A perovskite layer, characterized in that: the perovskite layer comprises a CsPbI 3 layer and a lead complex; the lead complex is distributed at grain boundaries and surfaces of the CsPbI 3 layer; and the perovskite layer is prepared from a precursor solution comprising any one of claims 5-6.

8. A method for producing a perovskite layer, characterized by: the perovskite layer is obtained by loading a substrate with the precursor solution comprising any one of claims 5-6 and then annealing. 9.A method for preparing the perovskite layer of claim 8, characterized in that: The thickness of the perovskite layer is 250-350 nm; and / or, The loading method is spin coating; and / or, The annealing temperature is 160-220℃; and / or, The annealing time is 10-60 min; and / or, The volume of the precursor solution used is 30-100 μL.

10. The method for preparing a perovskite layer according to claim 9, wherein: The spin coating speed is 2000-4000 rpm, and the time is 20-40 s.

11. A perovskite solar cell, wherein: The perovskite solar cell comprises the perovskite layer of claim 7 or the perovskite layer prepared by the method of any one of claims 8-9.

12. The perovskite solar cell according to claim 11, wherein: The perovskite solar cell comprises a bottom electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a top electrode.

13. The perovskite solar cell according to claim 12, wherein: The bottom electrode is FTO conductive glass; and / or, The electron transport layer is a TiO2 layer; and / or, The hole transport layer is Spiro-OMeTAD or copper phthalocyanine; and / or, The top electrode is gold or silver.

14. The perovskite solar cell according to claim 13, wherein: The FTO conductive glass has a square resistance of 5-30 Ω and a transmittance of 80-99%; and / or, The area of the bottom electrode is 1-9 cm 2 ; and / or, The thickness of the electron transport layer is 10-50 nm; and / or, The thickness of the hole transport layer is 150-200 nm; and / or, The thickness of the top electrode is 50-150 nm.

15. A method of producing a perovskite solar cell as claimed in any one of claims 11-14, characterized in that, comprising the following steps: Preparation of the electron transport layer: Spin coating the electron transport layer spin coating solution on the bottom electrode, annealing, and after cooling, performing plasma cleaning treatment; to obtain a bottom electrode / electron transport layer; Preparation of the perovskite layer: Spin coating the precursor solution on the electron transport layer, annealing, to obtain a bottom electrode / electron transport layer / perovskite layer; Preparation of the hole transport layer: Spin coating Spiro-OMeTAD spin coating solution on the perovskite layer, or vacuum evaporation of copper phthalocyanine onto the perovskite layer, to obtain a bottom electrode / electron transport layer / perovskite layer / hole transport layer; Preparation of the top electrode: Vacuum evaporation treatment of the obtained bottom electrode / electron transport layer / perovskite layer / hole transport layer to prepare the top electrode, or, on the bottom electrode / electron transport layer / perovskite layer / hole transport layer, to prepare the top electrode by doctor blading conductive carbon paste; to obtain the perovskite solar cell.

16. The method for preparing a perovskite solar cell according to claim 15, wherein: During the preparation of the electron transport layer, The electron transport layer spin coating solution is a TiO2 spin coating solution; During annealing, first annealing at 100-150℃ for 5-30 min, and then annealing at 450-550℃ for 30-100 min; The plasma cleaning treatment time is 3-10 min; and / or, The spin coating speed is 3000-6000 rpm, and the time is 20-40 s.

17. The method for preparing a perovskite solar cell according to claim 15, wherein: The Spiro-OMeTAD spin-coating liquid is spin-coated on the perovskite layer to prepare the hole transport layer, In the hole transport layer spin-coating liquid, 70-110 mg of Spiro-OMeTAD, 10-30 μL of lithium bis-trifluoromethanesulfonimide solution, 10-40 μL of FK209 solution, and 20-50 μL of 4-tert-butylpyridine are contained in each milliliter of solvent; and / or, The solvent in the hole transport layer spin-coating liquid is at least one of chlorobenzene and chloroform.

18. The method for preparing the perovskite solar cell according to claim 17, characterized in that: The lithium bis-trifluoromethanesulfonimide solution is an acetonitrile solution with a concentration of 520 mg / mL, and the FK209 solution is an acetonitrile solution with a concentration of 300 mg / mL; and / or, The spin-coating speed is 2000-4000 rpm, and the time is 20-40 s; and / or, When the copper phthalocyanine is vacuum evaporated onto the perovskite layer, the vacuum degree is less than 7x10 -4 Pa, and the evaporation current is 50-80 A. The vacuum degree of the vacuum evaporation treatment for the top electrode preparation is lower than 7x10 -4 Pa.

19. Use of the perovskite solar cell according to any one of claims 11-14 or prepared by the method according to any one of claims 15-18 in photovoltaic power generation.

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