Polymer perovskite thin film, preparation method, application, flexible solar cell

Abstract

The present invention discloses a polymer perovskite thin film, a preparation method, an application, and a flexible solar cell. The present invention provides a polymer perovskite thin film A, which comprises a polymer and a perovskite. Among them, the polymer is poly-V3D3, and the molecular formula of the perovskite is Cs x (FA y MA 1‑y ) 1‑x Pb(I z Br 1‑z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; The molar ratio of the V3D3 to the perovskite is (1-5):1000. The present invention also provides a preparation method of the polymer perovskite thin film and a flexible perovskite solar cell containing the same. The polymer can passivate defects, improve the stability of the perovskite, and can also play a role in bonding grains and buffering the impact during bending when bending. By adjusting the doping ratio of the crosslinking agent, flexible perovskite solar cells with different efficiencies and different degrees of bending resistance can be obtained. And only a small amount of doping is required to play a role during the production of the flexible perovskite battery.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor device fabrication, and particularly relates to a polymer perovskite thin film, a preparation method, an application, and a flexible solar cell. Background Art

[0002] Inorganic-organic hybrid perovskite solar cells were once rated as one of the top ten international scientific and technological advances in 2013 by Science. After only a few years of development, the efficiency of inorganic-organic hybrid perovskite solid-state planar solar cells has been increased to more than 25%. At the same time, it has the advantages of simple and diverse fabrication processes and light weight, and has a very bright application prospect. Against the background of vigorously developing clean energy in the future, it is very likely to complement silicon solar cells and play an important role in the photovoltaic field.

[0003] Flexible thin-film solar cells have the characteristics of light weight and wearable, meeting the requirements of future wearable devices. However, although traditional silicon solar cells have extremely high stability, due to their limitations in fabrication processes, material properties, and fabrication costs, it is difficult to make a major breakthrough in wearable flexible batteries. While organic polymer solar cells have extremely high flexibility, their fabrication costs are high, their stability is poor, and their efficiency cannot be compared with that of perovskite cells. Although there are also relevant reports on the application of CIGS, GaAs, etc. in flexible devices, their high costs limit their further development.

[0004] Renowned scholars in the industry have proved through research that polycrystalline perovskite batteries have low costs, are simple to prepare, and can be used to print large-area flexible devices, having the potential to meet the requirements of future wearable solar cell devices.

[0005] However, at present, the stability and anti-bending ability of polycrystalline perovskite flexible batteries are poor, and it is difficult to achieve large-scale applications. Therefore, how to obtain a perovskite flexible battery with good stability and strong anti-bending ability is a technical problem that urgently needs to be solved in this field.

[0006] CN106206949A discloses a flexible perovskite solar cell and a preparation method thereof. It is prepared by annealing treatment with a perovskite precursor solution containing an organic polymer. The thickness of the perovskite thin film containing the organic polymer is 200-400 nm. The organic polymer has the following characteristics: (1) having insulation properties; (2) being soluble in the solvent; (3) having no influence on light absorption and carrier transport; (4) not reacting with each component in the perovskite precursor solution.

[0007] Due to the doped organic polymer macromolecular materials (such as polyvinyl alcohol PVA, polyethylene glycol PEG) having extremely long molecular chains, a skeleton layer of the organic polymer is formed at the same time; it plays roles such as buffering bending stress and supporting the material structure in the crystal material, reducing the stress on the perovskite material during the bending process, and after the bending is restored, under the "traction" of the highly elastic organic molecular chains, it can be restored to the initial state in time, ensuring that the battery performance is not affected. The prepared flexible battery greatly improves the flexibility and stability of the device. After 100 bends with a curvature of 250, the battery performance is maintained at about 80% of the original. After 300 bends with a curvature of 250 on the device, the battery efficiency can be maintained at about 65% of the initial value.

[0008] However, it still has certain deficiencies. (1) The method of directly adding a large amount of linear ultra-long polymer macromolecules instead of in-situ formation may have problems such as uneven film formation, and it is not easy to achieve the operation of polymer enrichment at grain boundaries in a directional manner; the process design requirements for the operator are more complex. (2) When directly adding polymer macromolecules, issues such as the solubility of the solvent and the molecular weight of the polymer need to be considered, and there are higher requirements for solvent selection and the operator; it is not applicable to polymers that are not easily soluble or dispersed but may have a protective effect on perovskite polycrystals. (3) The degree of protection of the perovskite flexible battery and its anti-bending effect still need to be improved; (4) For the formal structure of this method, it is uncertain whether it can be applied to the inverted structure. (5) Although the hydroxyl groups in PVA can form a certain interaction with perovskite and have a potential passivation effect, whether its hydrophilicity itself will lead to a decrease in device stability remains to be discussed. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of poor stability and poor anti-bending ability when perovskite polycrystals are applied to flexible solar devices in the prior art, and to provide a polymer perovskite thin film, a preparation method, an application, and a flexible solar battery. The polymer perovskite thin film provided by the present invention is prepared by introducing crosslinkable monomers into the perovskite layer. The crosslinkable monomers can form a crosslinked polymer network during the annealing and crystallization process of perovskite. The polymer interacts with the perovskite grain boundaries, can passivate defects, improve the stability of perovskite, and can also play a role in bonding grains and buffering the impact between grains during bending. Compared with the battery without introducing a crosslinked structure or the battery introducing other polymers in the prior art, the flexible solar battery in the present invention has higher stability and anti-bending ability, and can better meet the stability and mechanical property requirements of flexible devices.

[0010] The present invention solves the above technical problems through the following technical solutions.

[0011] The present invention provides a polymer perovskite thin film A, which comprises a polymer and a perovskite. Among them, the polymer is poly-V3D3, and the molecular formula of the perovskite is Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; In the poly-V3D3, the monomer V3D3( Chinese name: 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, abbreviated as V3D3) and the perovskite have a molar ratio of (1 - 5):1000.

[0012] Among them, the polymer is preferably poly-V3D3 in-situ polymerized from the V3D3.

[0013] Among them, as is well known in the art, in the molecular formula of the perovskite, MA represents methylammonium ion (CH3NH3 + ; methylammonium), and FA represents formamidinium ion (HN=CH-NH3 + ; formamidinium).

[0014] As is well known in the art, one of the advantages of perovskite compared with other photovoltaic materials is that different components of the light-absorbing layer can be simply formed by changing the types and ratios of isovalent elements, that is, the composition and band gap are adjustable. The perovskite morphologies obtained by adjusting the content ratio of a certain element within a certain range are not significantly different.

[0015] In a certain embodiment of the present invention, the molecular formula of the perovskite can be Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3.

[0016] In the present invention, the perovskite is polycrystalline.

[0017] In a certain embodiment of the present invention, the molar ratio of the V3D3 and the perovskite can be (2 - 5):1000.

[0018] In a certain embodiment of the present invention, the polymer perovskite thin film A is composed of the polymer and the perovskite.

[0019] In a certain embodiment of the present invention, the polymer is located between the polycrystalline grains of the perovskite; it exists in the form of elastic grain boundaries.

[0020] In one embodiment of the present invention, the polymer covers the grain boundaries of the perovskite and penetrates into the grain boundaries (existing in the form of elastic grain boundaries).

[0021] In one embodiment of the present invention, the thickness of the polymer perovskite thin film A can be 400 - 600 nm (for example, 485 nm, which is estimated from the cross-sectional SEM test).

[0022] In the present invention, the polymer is a non-conductive polymer.

[0023] A method for preparing a polymer perovskite thin film, comprising the following steps:

[0024] Step 1: Perform anti-solvent extraction one-step method on the perovskite precursor solution and the anti-solvent to prepare a substrate;

[0025] Step 2: Anneal the obtained substrate to obtain a polymer perovskite thin film;

[0026] Among them, the perovskite precursor solution and / or the anti-solvent contain V3D3; the molecular formula of the perovskite is Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; the molar ratio of V3D3 to the perovskite is (1 - 5):1000.

[0027] Among them, the "anti-solvent extraction one-step method" is a conventional anti-solvent extraction one-step method in the art; it is developed from the conventional "one-step deposition method (OSPD)" in the art. The one-step deposition method is usually to deposit (for example, after dropping the perovskite precursor solution on the surface of the substrate layer or other functional layers), coat (the coating of the perovskite precursor solution can be spin coating, blade coating or slot coating) and deposit, and anneal and fix to obtain a (relatively thin) perovskite active layer.

[0028] In the present invention, the term "precursor solution" means that the precursor solution can be obtained by dissolving according to the ratio of various raw materials. In the present invention, the "perovskite precursor solution" refers to a solution containing the perovskite precursor, which is a form before obtaining the target product perovskite. In the present invention, the perovskite precursor solution is obtained by dissolving raw materials (such as CsI, MAI, PbI2, MABr, PbBr2) (for example, configured in a certain proportion) in a high-boiling polar solvent (such as N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and γ-butyrolactone (GBL), etc.) (for example, heating at 75 °C for 15 min can obtain it).

[0029] In this field, the so-called one-step anti-solvent extraction method is to add an anti-solvent (such as chlorobenzene, toluene, diethyl ether, etc.) to the surface of a perovskite precursor solution coating (the so-called anti-solvent coating can be spin coating, blade coating or slot coating) (such as rapid dropping) during the coating process, and rapidly change the polarity of the solution so that perovskite crystals are rapidly nucleated and precipitated from the original solvent to form a dense and uniform perovskite thin film.

[0030] In a certain embodiment of the present invention, the stoichiometric molecular formula of the perovskite precursor can be Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3. The perovskite precursor is obtained, for example, by configuring CsI, MAI, PbI2, MABr, and PbBr2 (for example, configured in proportion).

[0031] In a certain embodiment of the present invention, the molar ratio of the V3D3 to the perovskite is (2-5):1000.

[0032] In a certain embodiment of the present invention, the solvent in the perovskite precursor solution can be a conventional solvent in this field, such as at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and γ-butyrolactone (GBL); for example, DMF and / or DMSO, or for example, DMF:DMSO = 4:1 (volume ratio). The crosslinkable monomer V3D3 is dissolved in the solvent.

[0033] In a certain embodiment of the present invention, the anti-solvent can be a conventional anti-solvent (poor solvent) of the perovskite precursor in this type of method in this field. For example, the anti-solvent of the perovskite can be chlorobenzene and / or toluene; for example, chlorobenzene.

[0034] In a certain embodiment of the present invention, when the anti-solvent contains V3D3, the mass-volume ratio of the V3D3 in the anti-solvent can be 0.1-1 mg / mL; for example, 0.2-0.5 mg / mL.

[0035] In a certain embodiment of the present invention, the dosage of the anti-solvent can be the conventional dosage of the anti-solvent in this type of method in this field; for example, 100 μL - 200 μL / 2.25 cm 2 (for example, on a 1.5*1.5 cm 2 substrate); or for example, 100 μL - 170 μL / 2.25 cm 2 .

[0036] In a certain embodiment of the present invention, the molar concentration of the perovskite precursor (in terms of the stoichiometric molecular formula) in the perovskite precursor solution can be a conventional molar concentration in the art, such as 1 - 2 mol / L, or for example, 1.4 mol / L.

[0037] In the present invention, the annealing process is a polymerization process for the crosslinking monomer and a crystallization growth and stabilization process for the perovskite film. The annealing conditions and operations can be conventional conditions and operations in this type of method in the art; for example, pre-annealing, solvent annealing, and thermal annealing in sequence. The conditions and operations of the pre-annealing, solvent annealing, and thermal annealing can be conventional conditions and operations in this type of method in the art.

[0038] Among them, the purpose of the pre-annealing is to initiate (pre-polymerize) the monomer V3D3 to a certain extent first; then, in combination with the process of enriching the monomer during the subsequent solvent annealing, a full reaction can be achieved, avoiding heating to a relatively high temperature at the beginning, which may cause the monomer to volatilize and is not conducive to the full progress of the reaction. In a certain embodiment of the present invention, the pre-annealing can be the following steps: Under an inert atmosphere (such as in the presence of nitrogen), place the obtained substrate at room temperature (such as 10 - 30 °C, or for example, 25 °C) for 20 - 25 min (such as 20 min), and then heat it at 80 °C - 85 °C (such as 85 °C) for 1 min.

[0039] The purpose of the solvent annealing is for the secondary growth of the perovskite (polycrystalline), reducing grain boundaries. At the same time, since the monomer V3D3 is incompatible with the perovskite grains, it will be repelled to the grain boundaries during the secondary growth of the grains to play an enriching role.

[0040] In a certain embodiment of the present invention, the solvent annealing can be the following steps: After pre-annealing, on a hot plate at 100 °C (such as 100 °C), add the solvent (such as DMSO) around the substrate, then cover it with a watch glass, after solvent annealing at 100 °C for 20 min, open the watch glass to let the solvent atmosphere volatilize.

[0041] In the solvent annealing, the added solvent is DMSO. The amount of the solvent used can be a conventional amount in the art, for example, 0.2 - 0.5 μL / 2.25 cm 2 (such as 1.5 * 1.5 cm 2 substrate).

[0042] In a certain embodiment of the present invention, the thermal annealing is annealing at 100 degrees for 40 min.

[0043] In a certain embodiment of the present invention, the preparation method may include the following steps:

[0044] Step 1: Coating the perovskite precursor solution and coating the anti-solvent on its surface to prepare the substrate.

[0045] Step 2: Annealing the substrate obtained above, followed by crystallization and polymerization to obtain the polymer perovskite thin film.

[0046] Among them, the conditions and operations for coating the perovskite precursor solution and the anti-solvent can be the conventional conditions and operations in this type of coating in the art; for example, the coating of the perovskite precursor solution and the anti-solvent can independently be spin coating, blade coating, or slot coating.

[0047] In a certain embodiment of the present invention, in Step 1, in the one-step anti-solvent extraction method, the coating of the perovskite precursor solution can be the following spin coating procedure: the first step, 1000 revolutions for 10 s, the second step, 6000 revolutions for 16 s - 40 s (for example, 20 s).

[0048] In a certain embodiment of the present invention, in Step 1, in the one-step anti-solvent extraction method, the coating of the anti-solvent can be the following spin coating procedure: 4000 - 6000 revolutions for 4 s - 50 s; (for example, 6000 revolutions for 4 s, or the first step 6000 revolutions for 4 s, the second step 4000 revolutions for 40 s).

[0049] In a certain embodiment of the present invention, the preparation method can be Method 1, Method 2, or Method 3.

[0050] Method 1 includes the following steps:

[0051] Step 1: Coating the perovskite precursor solution and coating the anti-solvent containing V3D3 on its surface to obtain a substrate.

[0052] Step 2: Sequentially annealing the substrate obtained above, including pre-annealing, solvent annealing, and thermal annealing, followed by crystallization and polymerization to obtain the polymer perovskite thin film.

[0053] Method 2 includes the following steps:

[0054] Step 1: Coating the perovskite precursor solution and sequentially coating the anti-solvent and the anti-solvent containing V3D3 on its surface to obtain a substrate.

[0055] Step 2: Sequentially annealing the substrate obtained above, including pre-annealing, solvent annealing, and thermal annealing, followed by crystallization and polymerization to obtain the polymer perovskite thin film.

[0056] Method 3 includes the following steps:

[0057] Step 1: Coating the precursor solution of the perovskite containing V3D3, and coating an antisolvent on its surface to obtain a substrate;

[0058] Step 2: Annealing the substrate obtained above in sequence by pre-annealing, solvent annealing, and thermal annealing, and through crystallization and polymerization, the polymer perovskite thin film can be obtained.

[0059] The present invention also provides a polymer perovskite thin film B, which is prepared by the preparation method of the polymer perovskite thin film as described above.

[0060] In a certain embodiment of the present invention, the parameters of the polymer perovskite thin film B are as described in the polymer perovskite thin film A as described above.

[0061] The present invention also provides a composition for preparing polymer perovskite, which comprises V3D3 and a precursor of perovskite;

[0062] Wherein, the stoichiometric molecular formula of the precursor of perovskite is Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; the molar ratio of the V3D3 to the precursor of perovskite is (1 - 5):1000.

[0063] In a certain embodiment of the present invention, the stoichiometric molecular formula of the precursor of perovskite is Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 (i.e., x = 0.05); for example, it is prepared by proportionally configuring CsI, MAI, PbI2, MABr, and PbBr2.

[0064] In a certain embodiment of the present invention, the molar ratio of the V3D3 to the precursor of perovskite can be (2 - 5):1000.

[0065] In a certain embodiment of the present invention, the composition preferably exists in the form of a solution conventional in the art; for example, it exists in the form of a precursor solution of perovskite containing the V3D3. The solvent in the solution can be a solvent conventional in the art, such as the solvent conventionally used in the precursor solution of perovskite; preferably at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and γ-butyrolactone; for example, DMF and / or DMSO, or for example, DMF:DMSO = 4:1 (volume ratio). The molar concentration of the perovskite precursor in the solution can be a molar concentration conventional in the art, such as 1 - 2 mol / L, or for example, 1.4 mol / L.

[0066] In a certain embodiment of the present invention, the composition is as follows: Embodiment 1: It includes the V3D3 and the perovskite precursor; the molar ratio of V3D3 to the perovskite precursor is 1:1000, 2:1000, or 5:1000;

[0067] Embodiment 2: It includes the V3D3, the perovskite precursor, and a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1; the molar ratio of V3D3 to the perovskite precursor is 1:1000, 2:1000, or 5:1000; the molar concentration of the perovskite precursor in the composition is 1.4 mol / L.

[0068] The present invention also provides an application of V3D3 or the composition as described above in the preparation of a polymer perovskite thin film.

[0069] In the steps of the above application, the parameters of the polymer perovskite thin film can be any of the schemes described in the polymer perovskite thin film A or polymer perovskite thin film B as described above.

[0070] In the steps of the above application, the conditions and operations can refer to the conditions and operations in the preparation method of the polymer perovskite thin film as described above.

[0071] The present invention also provides a perovskite solar cell, wherein the light-absorbing layer (or active layer) is the polymer perovskite thin film A or the polymer perovskite thin film B as described above.

[0072] In the present invention, the perovskite solar cell generally includes a substrate layer, a hole transport layer, a light-absorbing layer, an electron transport layer, a blocking layer, and an electrode layer.

[0073] In the present invention, the perovskite solar cell can be a flexible perovskite solar cell; for example, the substrate can be a flexible substrate or a glass substrate conventional in the art, such as PEN / ITO.

[0074] Among them, the material of the hole transport layer can be a conventional organic semiconductor material in the art, such as PTAA, poly-TPD (poly[bis(4-phenyl)(4-butylphenyl)amine]), or PEDOT:PSS.

[0075] Preferably, when the flexible perovskite battery includes a hydrophobic hole transport layer (such as PTAA, poly-TPD), preferably, a PFN-Br layer is further included between the hole transport layer and the light-absorbing layer.

[0076] In the present invention, the PFN-Br layer can be prepared by a conventional method in the art. For example, a solution containing PFN-Br is coated, and the solvent in the solution is removed. In the solution containing PFN-Br, the concentration of PFN-Br can be 0.25 mg / mL. The solvent can be methanol.

[0077] Among them, the material of the electron transport layer can be a conventional material in the art, such as a polar polymer, a small molecule polymer, C 60 、C 60 carboxylated derivative, C 60 aminated derivative, C 60 hydroxylated derivative, and one or more of PCBM, preferably C 60 .

[0078] Among them, the material of the blocking layer can be a conventional wide-bandgap material in the art, preferably BCP (diphenyl-1,10-phenanthroline).

[0079] Among them, the material of the electrode layer can be a conventional electrode material in the art, such as a metal, such as Cu, Au, Ag, or Al.

[0080] In a certain embodiment of the present invention, the perovskite battery can be prepared by the following steps:

[0081] Step 1: It includes Scheme 1, Scheme 2, or Scheme 3;

[0082] Scheme 1 includes the following steps:

[0083] 1) Preparation of the V3D3 solution: V3D3 is dispersed in an antisolvent (or poor solvent) for perovskite such as chlorobenzene or toluene at a mass concentration of 0.1-1 mg / mL, and shaken well.

[0084] 2) Preparation of polymer perovskite thin film (active layer): Disperse PTAA in toluene, coat it on a flexible ITO substrate by spin coating method, and perform annealing treatment at 100 °C for 10 min. Spin coat the perovskite precursor solution (program spin coating steps: first step, 1000 rpm for 10 s; second step, 6000 rpm for 20 s) on the prepared PTAA / PFN-Br. Dropwise add the above-mentioned V3D3 solution within the last 4 s of the second step of 6000 rpm during the spin coating of the perovskite precursor solution. After pre-annealing (pre-polymerization), perform annealing at 100 °C for one hour (solvent (such as DMSO) annealing for 20 min, thermal annealing for 40 min) (to make the perovskite fully crystallize and at the same time make the V3D3 monomer fully thermally crosslinked); then the polymer perovskite thin film can be obtained;

[0085] Scheme 2 includes the following steps:

[0086] 1) Preparation of V3D3 solution: Disperse V3D3 in an antisolvent (or poor solvent) of perovskite such as chlorobenzene or toluene at a mass concentration of 0.1 - 1 mg / mL, and shake well;

[0087] 2) Preparation of polymer perovskite thin film (active layer):

[0088] Disperse PTAA in toluene, coat it on a flexible ITO substrate by spin coating method, and perform annealing treatment at 100 °C for 10 min. Spin coat the perovskite precursor solution on the prepared PTAA (program spin coating steps: first step, 1000 rpm for 10 s; second step, 6000 rpm for 20 s). Dropwise add the antisolvent within the last 4 s of the second step of 6000 rpm during the spin coating of the perovskite precursor solution. Continuously dropwise add the above-mentioned V3D3 solution and spin coat (4000 rpm, 40 s). After pre-annealing (pre-polymerization), perform annealing at 100 °C for one hour (solvent (such as DMSO) annealing for 20 min, thermal annealing for 40 min) (to make the perovskite fully crystallize and at the same time make the V3D3 monomer fully thermally crosslinked); then the polymer perovskite thin film can be obtained;

[0089] Scheme 3 includes the following steps:

[0090] Disperse PTAA in toluene, coat it on a flexible ITO substrate by spin coating, and perform annealing treatment at 100 °C for 10 min. Spin coat the perovskite precursor solution containing monomer V3D3 on the prepared PTAA (programmed spin coating steps: first step, 1000 rpm for 10 s; second step, 6000 rpm for 20 s); drop the anti-solvent within the last 4 s of the second step of 6000 rpm during the spin coating of the perovskite precursor solution; after pre-annealing (pre-polymerization), perform annealing at 100 °C for one hour (solvent (such as DMSO) annealing for 20 min, thermal annealing for 40 min) (to allow the perovskite to fully crystallize and at the same time allow the V3D3 monomer to fully thermally crosslink); then the polymer perovskite film can be obtained.

[0091] Step 2:

[0092] Deposit C 60 , BCP, and the metal electrode on the aforementioned polymer perovskite film respectively, and then a flexible perovskite solar cell (including crosslinked elastic grain boundaries) can be obtained.

[0093] By introducing the crosslinkable monomer V3D3, phase separation occurs during the process of perovskite solvent annealing crystallization, enriches at the grain boundaries, and crosslinks and solidifies to form an elastic grain boundary filling with a crosslinked network structure, which not only improves the stability of flexible perovskite solar cells but also improves the anti-bending ability of flexible perovskite solar cells.

[0094] Unless otherwise specified in the context, the following definitions for the terms cited below apply to this article:

[0095] "Monomer" refers to any molecule that can react with other identical or different molecules to form a polymer or a polymer.

[0096] On the basis of not violating the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0097] The reagents and raw materials used in the present invention are all commercially available.

[0098] The positive and progressive effects of the present invention are as follows:

[0099] (1) The preparation method of the present invention is simple, and a cross-linkable monomer is used, which is introduced into the perovskite layer in different forms. A cross-linked polymer network can be formed during the annealing and crystallization of the perovskite, and no cross-linking agent needs to be introduced. The functionality of the cross-linkable monomer V3D3 used is greater than or equal to 2, and thermal cross-linking can be performed to form a cross-linked network. The formation process is simple and efficient, and does not require complex instruments and equipment and a large amount of manpower. No other solvents need to be added during the preparation process, and no other initiators need to be introduced. Phase separation can be generated during the solvent annealing process during the perovskite film formation process, and the phase is enriched at the grain boundary and thermally initiated polymerization occurs. The cross-linkable monomer V3D3 used as the raw material is a common chemical raw material, which has been industrialized and is low in price. In the process of making flexible perovskite batteries, only a trace amount of doping is required to play a role.

[0100] (2) The cross-linkable monomer in the present invention can passivate defects and improve the stability of perovskite through interaction with the perovskite grain boundaries. It can also play a role in bonding grains and buffering the impact between grains during bending.

[0101] (3) The prepared flexible solar cell has higher stability and bending resistance than the cell without cross-linking structure, and can better meet the stability and mechanical performance requirements of flexible devices. The preparation of more stable flexible perovskite solar cells is in line with my country's concept of sustainable development and the public's requirements for the application of wearable devices. The introduction of this structure has certain guiding significance for accelerating the performance improvement and industrialization of flexible perovskite solar cells, which is conducive to the fuller utilization of solar energy resources.

[0102] (4) On the basis of introducing cross-linking monomers, a polymer modified layer PFN-Br is introduced between the hole transport layer and the perovskite light absorbing layer. By using amphiphilic polymers, the interface contact can be improved, the filling factor can be increased, and short circuits can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0103] Figure 1 This is a structural diagram of the flexible perovskite solar cell in Example 1.

[0104] Figure 2 , Figure 3 and Figure 4 This is a photograph of the flexible perovskite solar cell in Example 1 in a bent state.

[0105] Figure 5 The SEM images of the elastic grain boundaries in Example 1 and Comparative Example 1 in Effect Example 2, wherein: A refers to reference thermal annealing, B refers to reference solvent annealing, C refers to thermal annealing elastic grain boundary, D refers to solvent annealing elastic grain boundary, and E is a local enlarged view of D.

[0106] Figure 6It is the analysis diagram of the surface potential distribution of the devices in Example 1 and Comparative Example 1 in Effect Example 3.

[0107] Figure 7 It is the XRD diagram of the perovskite thin films in Example 2 and Comparative Example 1 in Effect Example 4.

[0108] Figure 8 It is the change diagram of the surface transient fluorescence spectrum of the perovskite thin films in Example 2 and Comparative Example 1 in Effect Example 4.

[0109] Figure 9 It is the change diagram of the space charge limited current of the perovskite thin films in Example 2 and Comparative Example 1 in Effect Example 4.

[0110] Figure 10 It is the change diagram of the electron migration of the perovskite thin films in Example 2 and Comparative Example 1 in Effect Example 4.

[0111] Figure 11 It is the lateral conductivity diagram of the perovskite thin films in Example 2 and Comparative Example 1 in Effect Example 4.

[0112] Figure 12 It is the longitudinal conductivity diagram of the perovskite thin films in Example 2 and Comparative Example 1 in Effect Example 4.

[0113] Figure 13 It is the IV curve of the flexible battery prepared in Example 2 and Comparative Example 1 in Effect Example 5.

[0114] Figure 14 It is the EQE test result of the reference device prepared in Comparative Example 1 in Effect Example 5.

[0115] Figure 15 It is the change trend diagram of the performance parameters of the flexible perovskite solar cell after the bending test in Example 2 and Comparative Example 1 in Effect Example 6.

[0116] Figure 16 It is the test diagram of the continuous output stability of the maximum power point of the flexible battery prepared in Example 2 and Comparative Example 1 in Effect Example 7.

[0117] Figure 17 It is the IV curve of the flexible battery prepared in Comparative Example 1 and Comparative Example 2 in Effect Example 8.

[0118] Figure 18 It is the surface morphology of the perovskite thin film prepared in Comparative Example 1 in Effect Example 9 after the destructive tensile experiment.

[0119] Figure 19 It is the surface morphology of the perovskite thin film prepared in Example 2 in Effect Example 9 after the destructive tensile experiment.

[0120] Figure 20 IV curves of the flexible batteries prepared in Example 2 of Effect Example 10 and Comparative Example 3. Detailed implementation manners

[0121] The present invention will be further illustrated by the following examples, but the present invention is not limited to the scope of the described examples. For the experimental methods without specific conditions indicated in the following examples, they are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0122] N,N'-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), chlorobenzene (CB).

[0123] Example 1

[0124] A preparation method of a cross-linked flexible perovskite solar cell, the steps of the method are as follows:

[0125] 1) Preparation of perovskite precursor solution: Dissolve CsI, MAI, PbI2, MABr, PbBr2 in a solvent of DMF:DMSO = 4:1 according to the formula Cs 0.05 Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3, the concentration of the prepared precursor solution is 1.4 mmol / mL, stir until completely dissolved, and continue to stir for about 12 hours before use.

[0126] 2) Dissolve PFN-Br in methanol at a concentration of 0.25 mg / mL to form a solution.

[0127] 3) Preparation of V3D3-containing solution: Prepare a chlorobenzene or toluene solution (such as chlorobenzene) of V3D3 at a mass volume concentration of 0.2 mg / mL, and shake well.

[0128] 4) Preparation of cross-linked flexible perovskite battery:

[0129] Disperse PTAA (2 mg) in toluene (1 mL), and coat it on a flexible ITO substrate (1.5 * 1.5 cm per piece) by spin coating (6000 rpm for 30 s) 2) Above (60 μL), and anneal at 100 °C for 10 min. Spin-coat the PFN-Br solution (70 μL) on PTAA at 4000 rpm for 40 s. Subsequently, spin-coat the perovskite precursor solution (120 μL) on the prepared PFN-Br (programmed spin-coating: the first step at 1000 rpm for 10 s, the second step at 6000 rpm for 20 s). During the last 4 s of the second step of 6000 rpm in the spin-coating of the perovskite precursor solution, add the V3D3-containing solution (100 μL) from step 3) (as an anti-solvent) onto the above perovskite precursor solution. Then, successively perform pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) for one hour to allow the perovskite to fully crystallize. Among them:

[0130] The operation of pre-annealing (pre-polymerization) is as follows: After adding the anti-solvent containing V3D3, the obtained perovskite thin film is first placed in a nitrogen glove box at room temperature (such as 25 °C) for 20 - 25 min (such as 20 min), and then annealed at 80 °C for 1 min;

[0131] The entire annealing process includes solvent annealing and thermal annealing, for a total of one hour. Solvent annealing is in the first 20 min. After 20 min, open the lid to let the atmosphere escape and continue to complete the remaining 40 min of thermal annealing at 100 °C.

[0132] Among them, the process conditions for solvent annealing are: Place the perovskite thin film obtained by pre-annealing (pre-polymerization) on a hot stage. The temperature of the hot stage is 100 °C. According to the amount of 0.2 - 0.5 μL of DMSO per substrate (1.5 * 1.5 cm 2 ), evenly drop it onto the hot stage and the periphery of the substrate (on the surface of the hot stage evenly distributed around the thin film), and cover a watch glass on the hot stage. After 20 min of solvent annealing, open the watch glass to let the solvent atmosphere escape;

[0133] Finally, deposit C 60 , BCP, and metal electrodes on the aforementioned thin film respectively to obtain a flexible perovskite solar cell with significantly improved anti-bending ability and stability compared to the uncrosslinked device. The specific structure is as Figure 1 shown.

[0134] Example 2

[0135] A preparation method of a cross-linked structure flexible perovskite solar cell, the steps of the method are as follows:

[0136] 1) Preparation of perovskite precursor solution: Mix CsI, MAI, PbI2, MABr, PbBr2 according to the formula Cs 0.05 Cs 0.05 (FA 0.83 MA 0.17 ) 0.95Pb(I 0.83 Br 0.17 )3 is dissolved in a solvent of DMF:DMSO = 4:1, and the concentration of the prepared precursor solution is 1.4 mmol / mL. Stir until completely dissolved, and continue stirring for about 12 hours before use.

[0137] 2) PFN-Br is dissolved in methanol at a concentration of 0.25 mg / mL to form a solution.

[0138] 3) Preparation of the V3D3-containing solution: V3D3 is doped into the precursor solution at a molar permillage of 2‰ with respect to the precursor and reserved for use. It can be prepared before use.

[0139] 4) Preparation of the cross-linked structure flexible perovskite solar cell:

[0140] Disperse PTAA (2 mg) in toluene (1 mL), and coat it on the flexible ITO substrate by spin coating (60 μL) (6000 rpm for 30 s), and perform annealing at 100 °C for 10 min. Spin coat the PFN-Br solution (70 μL) on PTAA (4000 rpm for 40 s). Subsequently, spin coat the perovskite precursor solution containing V3D3 (120 μL) on the prepared PFN-Br (programmed spin coating: the first step is 1000 rpm for 10 s, and the second step is 6000 rpm for 20 s). During the last 4 s of the second step of 6000 rpm in the spin coating of the perovskite precursor solution, add the antisolvent chlorobenzene (100 μL). Then, successively perform pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) for one hour to make the perovskite fully crystallize. Among them, the processes of successively performing pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) are the same as those in Example 1.

[0141] Finally, C 60 , BCP, and the metal electrode are respectively evaporated on the aforementioned film to obtain a flexible perovskite solar cell with significantly improved anti-bending ability and stability compared to the non-cross-linked device.

[0142] Comparison of different concentrations in Example 3

[0143] In step 3), the concentration of V3D3 in the V3D3 solution is 1‰, and the rest is the same as in Example 2.

[0144] Example 4

[0145] In step 3), the concentration of V3D3 in the V3D3 solution is 5‰, and the rest is the same as in Example 2.

[0146] Example 5

[0147] 1) Preparation of the perovskite precursor solution: Dissolve CsI, MAI, PbI2, MABr, PbBr2 according to the molecular formula Cs 0.05 Cs0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 is dissolved in a solvent of DMF:DMSO = 4:1, and the concentration of the prepared precursor solution is 1.4 mmol / mL. Stir until completely dissolved, and continue stirring for about 12 hours before use.

[0148] 2) PFN-Br is dissolved in methanol at a concentration of 0.25 mg / mL to form a solution.

[0149] 3) Preparation of the V3D3-containing solution: V3D3 is prepared into a chlorobenzene or toluene solution (such as chlorobenzene) at a mass-volume concentration of 0.2 mg / mL, and shaken well.

[0150] 4) Preparation of the cross-linked structure flexible perovskite solar cell:

[0151] PTAA is dispersed in toluene to form a 2 mg / ml solution, and is coated on a flexible ITO substrate (1.5*1.5 cm per piece 2 ) (60 μL) by spin coating, and annealed at 100 °C for 10 min. The PFN-Br solution (70 μL) is spin-coated (4000 rpm for 40 s) on PTAA. The perovskite precursor solution (120 μL) is spin-coated on the prepared PTAA / PFN-Br (120 μL, programmed spin coating, the first step is 1000 rpm for 10 s, the second step is 6000 rpm for 20 s, and 100 μL of the anti-solvent chlorobenzene is added dropwise at the fourth last second). 70 μL of the V3D3-containing solution is added dropwise onto the film after the anti-solvent treatment and spin-coated at 4000 rpm for 40 s. Then, it is successively subjected to pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) to obtain a perovskite film containing a polymer. Among them, the processes of successively undergoing pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) are the same as those in Example 1.

[0152] Finally, C 60 , BCP, and the metal electrode are respectively evaporated onto the aforementioned polymer perovskite film to obtain a (cross-linked elastic grain boundary) flexible perovskite solar cell.

[0153] Comparative Example 1

[0154] A preparation method of a flexible perovskite solar cell, the steps of the method are as follows:

[0155] 1) Preparation of the perovskite precursor solution: CsI, MAI, PbI2, MABr, PbBr2 are in accordance with the molecular formula Cs 0.05 Cs 0.05 (FA 0.83MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 is dissolved in a solvent of DMF:DMSO = 4:1, and the concentration of the prepared precursor solution is 1.4 mmol / mL. Stir until completely dissolved, and continue stirring for about 12 hours before use.

[0156] 2) PFN-Br is dissolved in methanol at a concentration of 0.25 mg / mL to form a solution.

[0157] 3) Preparation of flexible perovskite solar cells:

[0158] PTAA is dispersed in toluene to form a 2 mg / mL solution, which is spin-coated on a flexible ITO substrate and annealed at 100 °C for 10 min. The PFN-Br solution is spin-coated on PTAA, and then the perovskite precursor solution is spin-coated on the prepared PFN-Br. After that, annealing at 100 °C for one hour is carried out to allow the perovskite to crystallize fully. Among them, the annealing process is the same as that in Example 1.

[0159] Finally, C 60 , BCP and metal electrodes are respectively evaporated on the aforementioned film to obtain a flexible perovskite solar cell.

[0160] Comparative Example 2

[0161] A preparation method of a flexible perovskite solar cell, the steps of the method are as follows:

[0162] 1) Preparation of perovskite precursor solution: CsI, MAI, PbI2, MABr, PbBr2 are dissolved in a solvent of DMF:DMSO = 4:1 according to the formula Cs 0.05 Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3 is dissolved in a solvent of DMF:DMSO = 4:1, and the concentration of the prepared precursor solution is 1.4 mmol / mL. Stir until completely dissolved, and continue stirring for about 12 hours before use.

[0163] 2) Preparation of flexible perovskite solar cells:

[0164] Disperse PTAA in toluene, coat it on a flexible ITO substrate by spin coating, and perform annealing treatment at 100 °C for 10 min. Subsequently, spin coat the perovskite precursor solution on the prepared PTAA, and then perform pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) for one hour to allow the perovskite to fully crystallize. Among them, the processes of pre-annealing (pre-polymerization), solvent annealing, and annealing at 100 °C (thermal annealing) are the same as those in Example 1.

[0165] Finally, C 60 , BCP, and metal electrodes are respectively evaporated on the aforementioned film to obtain a flexible perovskite solar cell.

[0166] Comparative Example 3

[0167] In step 4), the pre-annealing (pre-polymerization) and solvent annealing processes are not carried out; after the anti-solvent treatment, thermal annealing is carried out at 100 °C for 1 h, and the rest is the same as in Example 2.

[0168] Comparative Example 4

[0169] In step 3), the concentration of V3D3 in the V3D3 solution is 8‰, and the rest is the same as in Example 2.

[0170] Effect Example 1

[0171] Bend the cross-linked structure flexible perovskite solar cell prepared in Example 1 in any direction (non-destructive) in air.

[0172] As Figures 2 - 4 shown, it can be seen that the flexible perovskite solar cell prepared in Example 1 can adapt to bending in air and undergo corresponding elastic deformation.

[0173] Effect Example 2

[0174] Use Hitachi SU8020 cold field emission scanning electron microscope for surface morphology analysis, with an acceleration voltage of 3 kV and a beam current density of 10 uA.

[0175] As Figure 5 shown, where:

[0176] A refers to reference thermal annealing, specifically, for the reference device in Comparative Example 1, after the perovskite layer is spin-coated, it is pre-annealed at 80 °C for 1 min, and then annealed at 100 °C for 1 h.

[0177] B refers to reference solvent annealing. Specifically, after the perovskite layer of the reference device in Comparative Example 1 was spin-coated, according to the equivalent of 0.5 μL DMSO solvent annealing per piece, it was solvent annealed at 100 °C for 20 min in a petri dish. Then, the petri dish was removed to allow air flow to ensure the elimination of the DMSO atmosphere, and annealing was continued for 40 min. After the solvent annealing process, secondary growth of the grains was achieved, and the grain size was significantly increased compared to the reference thermal annealing.

[0178] C refers to thermal annealing and elastic grain boundaries. Specifically, after adding a crosslinking monomer to the perovskite antisolvent, if the perovskite is directly treated by thermal annealing, no bright-colored substance can be seen enriched at the grain boundaries. The SEM images of the crosslinked device (Comparative Example 3) and the non-crosslinked device (Comparative Example 1) prepared without solvent annealing treatment have no obvious difference.

[0179] D refers to solvent annealing elastic grain boundaries. Specifically, the same content of crosslinking monomer as in C is added. Only by using the solvent annealing method to process the perovskite grains for secondary growth, the enrichment of the crosslinking monomer at the perovskite grain boundaries is achieved (the crosslinking monomer does not react with and is incompatible with the perovskite, and is in two phases), and the crosslinking reaction is achieved by heating.

[0180] D is a partial enlarged view of E. It can be seen that there are white substances with poor conductivity at the grain boundaries after solvent annealing.

[0181] According to Figure 5 it can be seen that the solvent annealing process not only realizes the growth of the perovskite grain size, but also realizes the enrichment of the crosslinking monomer. The monomer after enrichment makes the crosslinking reaction easier to proceed.

[0182] Effect Example 3

[0183] The elastic grain boundary flexible perovskite battery prepared in Example 1 and the reference flexible perovskite battery prepared in Comparative Example 1 were both analyzed for surface potential using the KPFM mode of an atomic force microscope (Brker Dimension FastScan).

[0184] The specific data can be seen in Table 1, Figure 6 .

[0185] Table 1

[0186]

[0187] From Table 1, Figure 6 it can be seen that when two perovskite films with similar roughness are selected for Kelvin probe force microscopy testing, due to the filling of the insulating elastic polymer for the grain boundaries, there is an obvious potential difference between the grains and grain boundaries of the crosslinked perovskite film, while the potential difference between the reference grains and grain boundaries is not obvious.

[0188] Effect Example 4

[0189] (1) XRD

[0190] Take the perovskite thin films in Example 2 and Comparative Example 1 and detect their XRD patterns. Among them, an X-ray diffractometer (Empyrean) was used to obtain the XRD spectrum. Specifically: under the conditions of 40 kV and 30 mA, the XRD spectrum was obtained by diffraction of a Cu tube.

[0191] According to Figure 7 it can be seen that the polymer elastic grain boundaries formed by the crosslinking monomers do not affect the crystallinity of the perovskite.

[0192] (2) Transient fluorescence

[0193] Take the perovskite thin films in Example 2 and Comparative Example 1 and detect their transient fluorescence changes. The instrument used was Edinburgh FLS920, and the time-correlated single-photon counting method was adopted. The laser excitation source was 400.8 nm.

[0194] Figure 8 It is a TRPL graph, which represents the changes in the transient fluorescence spectra brought about by the elastic grain boundaries and the reference grain boundaries. The average fluorescence lifetime of the reference sample is 31.66 ns, and the average fluorescence lifetime of the elastic grain boundary sample is 127.89 ns. Figure 8 It shows that the fluorescence lifetime on the crystal surface with elastic grain boundaries becomes longer and the surface defects are fewer.

[0195] (3) Space-charge-limited current

[0196] Take the perovskite thin films prepared in Example 2 and Comparative Example 1 and compare their space-charge-limited current (SCLC). The specific detection method is as follows: First, evaporate 20 nm of C on ITO 60 , and then prepare a reference and a polycrystalline perovskite thin film with elastic grain boundaries on C 60 . Then, evaporate C on the surface of the perovskite thin film 60 (20 nm) / BCP (7.5 nm), and then evaporate a copper electrode to prepare a single-electron device, and measure the current-voltage curve in the dark state.

[0197] The specific data can be seen in Table 2 below Figure 9 .

[0198] Table 2

[0199]

[0200] The linear fitting graph of the data in Table 2 can be seen in Figure 9 .

[0201] According to Table 2Figure 9 It can be seen that the n t (density of trapped states) of the perovskite thin film with an elastic grain boundary formed by a crosslinking monomer and the perovskite thin film without an elastic grain boundary formed by a crosslinking monomer are 6.74×10 15 cm -2 and 1.24×10 16 cm -2 respectively. Thus, it can be seen that the surface defects of the perovskite thin film with an elastic grain boundary formed by a crosslinking monomer are significantly reduced.

[0202] (4) Conductive performance

[0203] ① Take the perovskite thin films in Example 2 and Comparative Example 1 and detect their electron mobilities.

[0204] Table 3 below shows the detection results of the ion mobilities of the solar devices on the above copper electrodes. Among them, the detection method of electron mobility is: the same as the SCLC source and device structure, and the calculation formula of electron mobility is (J D is the current density, ε is the relative permittivity, ε0 is the vacuum permittivity, μ is the mobility, V b is the applied voltage, and L is the film thickness)

[0205] Table 3

[0206]

[0207] From Table 3, Figure 10 it can be seen that compared with the reference device, the electron mobility of the V3D3 crosslinked device has increased by two orders of magnitude. The electron mobility of the reference device is 1.02×10 -5 cm 2 v -1 s -1 , and the electron mobility of the V3D3 crosslinked device is about 1.03×10 -3 cm 2 v -1 s -1 .

[0208] ② Take the perovskite thin films in Example 2 and Comparative Example 1, use an etched ITO counter electrode (the electrode spacing is 60um, the electrode width is 2mm, deposit the reference and elastic grain boundary perovskite polycrystalline thin films between the electrodes respectively, and then conduct IV tests respectively) to detect their lateral conductive performance. The effective area used for the test is 0.0012 square centimeters (electrode spacing 60 microns, width 2mm).

[0209] Longitudinal device preparation and testing: The reference perovskite thin film (Comparative Example 1) and the elastic grain boundary polycrystalline perovskite thin film (Example 2) were directly prepared on the ITO electrode. Then, the gold electrode was deposited by masking to obtain the longitudinal conductivity test device. The longitudinal device was subjected to IV testing in a nitrogen glove box.

[0210] Table 4 below shows the detection results of the lateral and longitudinal conductivity of the above solar devices.

[0211] Table 4

[0212]

[0213] From Table 4, Figure 11 , Figure 12 it can be seen that the insulating elastic grain boundary encapsulation effectively reduces the charge concentration at the grain boundaries, thereby suppressing the charge recombination on the perovskite grain boundaries and enhancing the vertical charge transport performance ( Figure 12 ) and blocking the lateral charge transport path ( Figure 11 ).

[0214] Effect Example 5

[0215] (1) The devices prepared in Example 2 and Comparative Example 1 were tested using a Keithley 2400 digital source meter to obtain the IV curves of the fabricated flexible batteries. The light source used was the AAA-level solar simulator of Yiguang Technology, AM1.5G. The scanning range was -100 mV - 1200 mV, and the scanning delay was 33 ms.

[0216] The specific data can be seen in Table 5, Figure 13 .

[0217] Table 5

[0218] Number <![CDATA[V OC (V)]]> <![CDATA[J SC (mA·cm -2 )]]> FF(%) PCE(%) Example 2 1.08 22.33 82.93 20.00 Comparative Example 1 1.06 21.49 81.83 18.64

[0219] From Table 5, Figure 13 it can be seen that the PCE of the flexible battery fabricated by the present invention exceeds 19%, and the fill factor exceeds 78%.

[0220] (2) Take the flexible device prepared in Comparative Example 1 and perform EQE testing. The specific testing method is the QTest Hifinity5 testing system of Yiguang Technology. Specifically, it can be seen in Figure 14 .

[0221] From Figure 14 it can be seen that the integrated calculated current of the reference device of the flexible battery prepared in Comparative Example 1 is 21.26 mA / cm 2 (AM1.5G), which is basically consistent with the IV test results and the current is accurate.

[0222] Effect Example 6

[0223] The flexible perovskite solar cell samples prepared in Example 2 and Comparative Example 1 were placed in a nitrogen glove box. A steel rod with a 5-mm diameter made of 304 stainless steel was closely attached to the back of the flexible cell. The bending radius was controlled at 2.5 mm. After multiple bends, the changes in their performance parameters were tested, and the performance trend was recorded.

[0224] The specific data can be seen in Table 6, Figure 15 .

[0225] Table 6

[0226]

[0227]

[0228] Note: " / " indicates that the detection was not carried out. Since the reference device had basically lost its photovoltaic performance after 700 bends and was damaged, there was no need to continue the test.

[0229] From Table 6, Figure 15 it can be seen that the flexible cell containing the V3D3 cross-linking agent (Example 2) still maintained 73% of its initial efficiency after 10,000 rigorous bends.

[0230] Effect Example 7

[0231] The flexible perovskite solar cells prepared in Example 2 and Comparative Example 1 were placed under a calibrated light source, and the light intensity was maintained at 100 mW / cm 2 . The digital source meter bias voltage was set, and the device was controlled to continuously output at the maximum power point, and the change in device efficiency was continuously detected.

[0232] The specific data is shown in Table 7, Figure 16 .

[0233] Table 7

[0234]

[0235] According to Table 7, Figure 16 it can be seen that the continuous light stability of the elastic grain boundary sample has been greatly improved compared to the reference.

[0236] Effect Example 8

[0237] The devices prepared in Comparative Example 1 and Comparative Example 2 were tested using a Keithley 2400 digital source meter to obtain the IV curves of the fabricated flexible cells. The light source used was a AAA-class solar simulator from Yiguang Technology, AM1.5G. The scanning range was -100 mV - 1200 mV, and the scanning delay was 33 ms.

[0238] The specific data can be seen in Table 8, Figure 17 .

[0239] Table 8

[0240] Number <![CDATA[V OC (V)]]> <![CDATA[J SC (mA·cm -2 )]]> FF(%) PCE(%) Comparative Example 1 1.06 21.49 81.83 18.64 Comparative Example 2 1.07 18.61 69.22 13.80

[0241] From Table 8, Figure 17 it can be seen that when comparing the photovoltaic performance of the PFN-Br modified device with that of the unmodified device, the performance of the modified device has been significantly improved.

[0242] Effect Example 9

[0243] The devices prepared in Examples 2-4 and Comparative Example 4 were tested by a Keithley 2400 digital source meter to obtain the IV curves of the fabricated flexible batteries. The light source used was the AAA-level solar simulator of Yiguang Technology, AM1.5G. The scanning range was -100 mV - 1200 mV, and the scanning delay was 33 ms.

[0244] The specific data can be seen in Table 9.

[0245] Number <![CDATA[V OC (V)]]> <![CDATA[J SC (mA·cm -2 )]]> FF(%) PCE(%) Example 3 (1‰) 1.04 20.71 76.61 16.50 Example 2 (2‰) 1.04 20.75 76.09 16.42 Example 4 (5‰) 1.04 20.74 74.32 16.03 Comparative Example 4 (8‰) 1.03 20.82 70.74 15.17

[0246] The above data are pre-experiments to explore the simple monomer doping amount ratio in larger area devices (at the stage of unoptimized devices, only the same structure is selected to explore the doping concentration conditions). From the pre-experiment results in Table 9, it can be seen that within the range of 1‰ - 5‰ selected in this paper, the doping of the simple monomer will not have an obvious side effect on the device efficiency; however, when exceeding the range (the selected ratio of 8‰ is used for verification), the voltage, efficiency, and fill factor of the device are all affected to a certain extent.

[0247] Effect Example 10

[0248] The perovskite films prepared in Example 2 and Comparative Example 1 were taken for a destructive tensile test. The specific experimental method is as follows: Using an Instron universal material testing machine in the United States, the tensile force is 2 kN. The perovskite film is prepared on a flexible substrate and cut into long strips of 2 cm * 5 cm.

[0249] Figure 18 It shows that when the flexible device without elastic grain boundary protection is subjected to external force destruction and stretching, the film breaks irregularly, while Figure 19 after having elastic grain boundary protection, even if it is damaged and broken, many grains tend to maintain their stable shapes respectively.

[0250] Effect Example 11

[0251] Take the flexible batteries prepared in Example 2 and Comparative Example 3, and test them with a Keithley 2400 digital source meter to obtain the IV curves of the prepared flexible batteries. The light source used is the AAA-level solar simulator of Yiguang Technology, AM1.5G. The scanning range is -100 mV - 1200 mV, and the scanning delay is 33 ms.

[0252] The specific data can be seen in Table 10, Figure 20 .

[0253] Table 10

[0254] Number <![CDATA[V OC (V)]]> <![CDATA[J SC (mA·cm -2 )]]> FF(%) PCE(%) Comparative Example 3 1.10 22.95 58.03 14.65 Example 2 1.07 22.87 72.04 17.63

[0255] From Table 10, Figure 20 it can be seen that when comparing the photovoltaic performance of the device annealed with solvent and the device not annealed with solvent, the performance of the device annealed with solvent has been significantly improved.

[0256] The above examples show that the perovskite flexible solar cells prepared by the present invention have good performance, low cost, wide application range, and broad application prospects and commercial value.

Claims

1. A polymer perovskite thin film A, characterized in that, It includes a polymer and a perovskite, wherein the polymer is poly-V3D3, and the molecular formula of the perovskite is Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; The molar ratio of the monomer V3D3 in the poly-V3D3 to the perovskite is (1 - 5):1000.

2. The polymer perovskite thin film A as described in claim 1, wherein the polymer is poly-V3D3 in-situ polymerized from V3D3; and / or, the molecular formula of the perovskite is Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3; and / or, the perovskite is polycrystalline; and / or, the molar ratio of the V3D3 to the perovskite is (2 - 5):1000; and / or, the polymer perovskite thin film A is composed of the polymer and the perovskite; and / or, the thickness of the polymer perovskite thin film A is 400 - 600 nm; and / or, the polymer is located between the polycrystalline grains of the perovskite; or, the polymer covers the grain boundaries of the perovskite and penetrates into the grain boundaries.

3. A method for preparing a polymer perovskite thin film; characterized in that, It includes the following steps: Step 1, subject the precursor solution of the perovskite and the anti-solvent to a one-step anti-solvent extraction to prepare a substrate; Step 2, anneal the above substrate to obtain the polymer perovskite thin film. Among them, the precursor solution of perovskite and / or the antisolvent contain V3D3; the molecular formula of the perovskite is Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; the molar ratio of the V3D3 to the perovskite is (1 - 5):1000.

4. The preparation method as described in claim 3; wherein the molar ratio of the V3D3 to the perovskite is (2 - 5):1000; and / or, the solvent in the precursor solution of the perovskite is at least one of N,N-dimethylformamide, dimethyl sulfoxide, and γ-butyrolactone; and / or, the anti-solvent is chlorobenzene and / or toluene; and / or, when the anti-solvent contains V3D3, the mass-volume ratio of the V3D3 in the anti-solvent is 0.1 - 1 mg / mL; and / or, the dosage of the anti-solvent is 100 μL - 200 μL / 2.25 cm 2 ; and / or, based on the stoichiometric molecular formula, the molar concentration of the perovskite precursor in the perovskite precursor solution is 1 - 2 mol / L; and / or, the annealing is successively pre-annealing, solvent annealing, and thermal annealing; and / or, the preparation method includes the following steps: Step 1, coat the precursor solution of the perovskite and coat the anti-solvent on its surface to prepare the substrate; Step 2, anneal the substrate obtained above, and through crystallization and polymerization, obtain the polymer perovskite thin film.

5. The preparation method as described in claim 4; wherein the solvent in the precursor solution of the perovskite is N,N-dimethylformamide and / or dimethyl sulfoxide; and / or, the anti-solvent is chlorobenzene; and / or, the preparation method includes the following steps: Step 1, coat the precursor solution of the perovskite and coat the anti-solvent on its surface to prepare the substrate; the coating of the perovskite precursor solution and the coating of the anti-solvent are independently spin coating, blade coating, or slot coating; Step 2, anneal the substrate obtained above, and through crystallization and polymerization, obtain the polymer perovskite thin film.

6. The preparation method as described in claim 5; wherein the solvent in the precursor solution of the perovskite is N,N-dimethylformamide and dimethyl sulfoxide, and their volume ratio is 4:

1.

7. The preparation method as described in claim 4; wherein when the anti-solvent contains V3D3, the mass-volume ratio of the V3D3 in the anti-solvent is 0.2 - 0.5 mg / mL; And / or, the dosage of the anti-solvent is 100 μL - 170 μL / 2.25 cm 2 ; And / or, in terms of the stoichiometric molecular formula, the molar concentration of the perovskite precursor in the perovskite precursor solution is 1.4 mol / L; And / or, in the annealing process, the pre-annealing is as follows: under an inert atmosphere, place the obtained substrate at 10 - 30 °C for 20 - 25 min, and then heat it at 80 °C - 85 °C for 1 min; And / or, in the annealing process, the solvent annealing is as follows: after pre-annealing, add the solvent around the substrate at 100 °C, then cover it with a watch glass. After solvent annealing at 100 °C for 20 min, open the watch glass to let the solvent atmosphere volatilize; And / or, in the annealing process, the solvent for the solvent annealing is DMSO; And / or, in the annealing, the dosage of the solvent in the solvent annealing is 0.2 - 0.5 μL / 2.25 cm 2 ; And / or, in the annealing process, the thermal annealing is at 100 °C for 40 min; And / or, in step 1, in the anti-solvent extraction one-step method, the coating of the perovskite precursor solution is a spin-coating procedure as follows: the first step is 1000 revolutions for 10 s, and the second step is 6000 revolutions for 16 s - 40 s; And / or, in step 1, in the anti-solvent extraction one-step method, the coating of the anti-solvent is a spin-coating procedure as follows: 4000 - 6000 revolutions for 4 s - 50 s; And / or, the preparation method is Method 1, Method 2 or Method 3; Method 1 includes the following steps: Step 1: Coat the perovskite precursor solution; Drop and coat the anti-solvent containing V3D3 on the surface of the above perovskite precursor solution to obtain a substrate; Step 2: Subject the obtained substrate to pre-annealing, solvent annealing, and thermal annealing in sequence, and obtain the polymer perovskite thin film through crystallization and polymerization; Method 2 includes the following steps: Step 1: Coat the perovskite precursor solution; Drop and coat the anti-solvent and the anti-solvent containing V3D3 on the surface of the above perovskite precursor solution in sequence to obtain a substrate; Step 2: Subject the obtained substrate to pre-annealing, solvent annealing, and thermal annealing in sequence, and obtain the polymer perovskite thin film through crystallization and polymerization; Method 3 includes the following steps: Step 1: Coat the perovskite precursor solution containing V3D3; Drop and coat the anti-solvent on the surface of the above perovskite precursor solution to obtain a substrate; Step 2: Subject the obtained substrate to pre-annealing, solvent annealing, and thermal annealing in sequence, and obtain the polymer perovskite thin film through crystallization and polymerization.

8. The preparation method according to claim 7; characterized in that In step 1, in the anti-solvent extraction one-step method, the coating of the perovskite precursor solution is a spin-coating procedure as follows: the first step is 1000 revolutions for 10 s, and the second step is 6000 revolutions for 20 s; And / or, in step 1, in the anti-solvent extraction one-step method, the coating of the anti-solvent is a spin-coating procedure as follows: 6000 revolutions for 4 s, or the first step is 6000 revolutions for 4 s, and the second step is 4000 revolutions for 40 s.

9. A polymer perovskite thin film B, characterized in that, It is prepared by the preparation method according to any one of claims 3 - 8.

10. The polymer perovskite thin film B according to claim 9, characterized in that, The polymer perovskite thin film B described above is the thin film as described in Claim 1 or 2.

11. A composition for preparing polymeric perovskite; characterized in that, It includes a precursor of V3D3 and perovskite; Among them, the stoichiometric molecular formula of the perovskite precursor is Cs x (FA y MA 1-y ) 1-x Pb(I z Br 1-z )3; 0 ≤ x < 1; 0 ≤ y ≤ 1; 0 ≤ z ≤ 1; the molar ratio of the V3D3 to the perovskite precursor is (1 - 5):1000.

12. The composition for preparing a polymeric perovskite according to claim 11, wherein, The stoichiometric molecular formula of the perovskite precursor is Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 )3; and / or, the molar ratio of the V3D3 to the precursor of perovskite is (2 - 5):1000; and / or, the composition is a precursor solution of perovskite containing V3D3 in the method for preparing a polymer perovskite thin film as described in Claim 3.

13. The composition for preparing polymeric perovskite according to claim 11, characterized in that, The composition is as follows: It includes the V3D3 and the precursor of perovskite; the molar ratio of the V3D3 to the precursor of perovskite is 1:1000, 2:1000 or 5:1000.

14. The composition for preparing a polymeric perovskite according to claim 11, characterized in that, The composition is as follows: It includes the V3D3, the precursor of perovskite and a mixed solvent of N,N - dimethylformamide and dimethyl sulfoxide with a volume ratio of 4:1; the molar ratio of the V3D3 to the precursor of perovskite is 1:1000, 2:1000 or 5:1000; the molar concentration of the precursor of perovskite in the composition is 1.4 mol / L.

15. Use of a composition as described in any one of Claims 11 - 14 in the preparation of a polymer perovskite thin film.

16. The use as described in Claim 15; characterized in that the polymer perovskite thin film is the thin film as described in any one of Claims 1, 2 or 9 - 10; and / or, in the use, the conditions and operations are as in the method for preparing a polymer perovskite thin film as described in any one of Claims 3 - 8.

17. A perovskite solar cell, characterized in that, Wherein, the light - absorbing layer is the polymer perovskite thin film A as described in Claim 1 or 2 or the polymer perovskite thin film B as described in Claim 9.

18. The perovskite cell according to claim 17, wherein, The perovskite cell includes a substrate layer, a hole - transporting layer, a light - absorbing layer, an electron - transporting layer, a blocking layer and an electrode layer.

19. The perovskite cell according to claim 18, wherein, The perovskite cell is a flexible perovskite cell.

20. The perovskite cell according to claim 18, wherein The substrate layer is a flexible substrate layer or a glass substrate layer.

21. The perovskite cell according to claim 20, wherein, The substrate layer is PEN / ITO.

22. The perovskite cell according to claim 18, wherein, The material of the hole - transporting layer is PTAA, poly - TPD or PEDOT:PSS.

23. The perovskite battery according to claim 18, characterized in that, There is also a PFN - Br layer between the hole - transporting layer and the light - absorbing layer.

24. The perovskite battery according to claim 18, wherein The electron transport layer is one or more of a polar polymer, a small molecule polymer, C 60 , C 60 carboxylated derivatives, C 60 aminated derivatives, C 60 hydroxylated derivatives, and PCBM.

25. The perovskite cell according to claim 24, wherein The electron transport layer described above is C 60 .

26. The perovskite cell according to claim 18, characterized in that, The blocking layer is a wide - bandgap material.

27. The perovskite battery according to claim 26, characterized in that, The blocking layer is BCP.

28. The perovskite cell according to claim 18, wherein The electrode layer is Cu, Au, Ag or Al.

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