A preparation method and structure of perovskite battery

Abstract

The present invention provides a method and structure for preparing a perovskite cell, comprising the following steps: providing a conductive substrate, forming a first hole transport layer on the conductive substrate; forming a first perovskite light-absorbing layer; mixing a piperazine carboxylic acid compound with an organic solvent in a preset ratio to form a passivation treatment solution, applying the passivation treatment solution to the surface of the first perovskite light-absorbing layer, and performing an annealing treatment to form a first interface passivation layer; forming a first electron transport layer; and forming a first electrode layer. By introducing a specific interface passivation layer, the present invention effectively passivates defects on the surface of the first perovskite light-absorbing layer and at its grain boundaries, and reduces the interface defect state density between the first perovskite light-absorbing layer and the first electron transport layer, thereby effectively suppressing the occurrence of non-radiative recombination processes. In addition, the interface passivation layer also optimizes the band structure of the first perovskite light-absorbing layer, significantly improving the carrier extraction efficiency, thereby significantly improving the overall performance of the perovskite solar cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar cells and relates to a preparation method and structure of a perovskite cell. Background Art

[0002] Perovskite cells, an emerging photovoltaic technology, have become a hot topic in the photovoltaic field due to their simple structure, low cost, excellent photoelectric performance, and straightforward fabrication process. Perovskite materials possess excellent photoelectric conversion properties, such as high absorption coefficient, long carrier diffusion length, and high carrier mobility. These characteristics have enabled perovskite solar cells to rapidly surpass the efficiency of traditional silicon-based solar cells in just a few years.

[0003] However, the performance of perovskite solar cells has been hampered by defects within the perovskite film's grain boundaries and at the interface between the perovskite film and the charge transport layer. These defects can lead to increased non-radiative recombination, which in turn reduces carrier lifetime and weakens cell performance. In particular, defects at the interface between the perovskite film and the charge transport layer typically have a defect state density 1-2 times higher than that within the film itself, significantly negatively impacting the overall efficiency of the cell.

[0004] Therefore, how to provide a preparation method and structure of a perovskite battery to reduce the interface defects between the perovskite thin film layer and the charge transfer layer and passivate the grain boundary defects of the perovskite thin film layer has become an important technical problem that needs to be solved urgently by those skilled in the art.

[0005] It should be noted that the above introduction to the technical background is merely intended to provide a clear and complete description of the technical solutions of this application and facilitate understanding by those skilled in the art. Simply because these solutions are described in the background technology section of this application, it should not be assumed that the above technical solutions are well known to those skilled in the art. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the object of the present invention is to provide a preparation method and structure of a perovskite cell, which is used to solve the problem in the prior art that the performance of the perovskite cell is reduced due to grain boundary defects within the perovskite thin film layer and interface defects between the perovskite thin film layer and the charge transfer layer.

[0007] To achieve the above-mentioned and other related purposes, the present invention provides a method for preparing a perovskite battery, comprising the following steps:

[0008] Providing a conductive substrate, and forming a first hole transport layer on the conductive substrate;

[0009] forming a first perovskite light absorbing layer on the first hole transport layer;

[0010] Mixing a piperazine carboxylic acid compound and an organic solvent in a preset ratio to form a passivation solution, applying the passivation solution to the surface of the first perovskite light-absorbing layer, and performing an annealing treatment to form a first interface passivation layer;

[0011] forming a first electron transport layer on the first interface passivation layer;

[0012] A first electrode layer is formed on the first electron transport layer.

[0013] Optionally, the piperazine carboxylic acid compound includes at least one of piperazine-DL-malate, 2-piperazineacetic acid and 4-piperazinebenzoic acid.

[0014] Optionally, the concentration range of the piperazine carboxylic acid compound in the passivation treatment solution is 0.1 to 2 mg / mL.

[0015] Optionally, the thickness of the first interface passivation layer is in the range of 1 to 15 nanometers.

[0016] Optionally, the organic solvent includes at least one of isopropanol, methanol, ethanol and ethyl acetate.

[0017] Optionally, the material of the first perovskite light absorbing layer has a general structural formula of ABX3, wherein A is MA + , FA + 、Cs + Any one or a combination of at least two of the following, B is Pb 2+ 、Sn 2+ 、Ge 2+ Any one or a combination of at least two of - 、Cl - , I - Br - Any one or a combination of at least two of .

[0018] Optionally, the method further includes forming a bottom battery structure layer, wherein the bottom battery structure layer is formed on the surface of the first electrode layer.

[0019] Optionally, the formation of the bottom battery structure layer includes the following steps:

[0020] forming a second hole transport layer on the first electrode layer;

[0021] forming a second perovskite light absorption layer on the second hole transport layer, wherein the band gap of the material of the second perovskite light absorption layer is smaller than the band gap of the material of the first perovskite light absorption layer;

[0022] forming a second interface passivation layer on the second perovskite light absorbing layer;

[0023] forming a second electron transport layer on the second interface passivation layer;

[0024] A second electrode layer is formed on the second electron transport layer.

[0025] Optionally, the process of forming the second interface passivation layer includes: preparing a passivation solution, coating the passivation solution on the second perovskite light-absorbing layer, and performing annealing treatment to form the second interface passivation layer, wherein the composition of the passivation solution used to form the second interface passivation layer is the same as or different from the composition of the passivation treatment solution used to form the first interface passivation layer.

[0026] The present invention also provides a perovskite cell structure, which includes a conductive substrate, a first hole transport layer, a first perovskite light absorption layer, a first interface passivation layer, a first electron transport layer and a first electrode layer stacked in sequence, wherein the perovskite cell structure is obtained using any of the above-mentioned perovskite cell preparation methods.

[0027] As described above, the present invention provides a method and structure for preparing a perovskite cell. This method significantly improves the performance of the perovskite cell by introducing a specific interface passivation layer between the first perovskite light-absorbing layer and the first electron transport layer. The introduction of this interface passivation layer effectively passivates defects on the surface of the first perovskite light-absorbing layer and at its grain boundaries, and reduces the density of interface defect states between the first perovskite light-absorbing layer and the first electron transport layer, thereby effectively suppressing the occurrence of non-radiative recombination processes. In addition, the interface passivation layer also optimizes the band structure of the first perovskite light-absorbing layer, significantly improving the carrier extraction efficiency, and thus significantly improving the overall performance of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Shown is a process flow chart of the preparation method of the perovskite battery of the present invention.

[0029] Figure 2 It is a schematic diagram showing the cross-sectional structure of a perovskite cell formed in Example 1 according to the preparation method of the perovskite cell of the present invention.

[0030] Figure 3 FIG2 shows a scanning electron microscope image of a perovskite cell fabrication method according to a specific example of the present invention after forming a first interface passivation layer on the surface of the first perovskite light-absorbing layer. ...

[0031] Figure 4 Shown are the current density and voltage characteristic curves of a perovskite cell formed in a specific example of the perovskite cell preparation method of the present invention.

[0032] Figure 5The figure shows a scanning electron microscope image of a comparative example in which no first interface passivation layer is formed on the surface of the first perovskite light-absorbing layer.

[0033] Figure 6 Shown is the current density and voltage characteristic curve of the perovskite battery formed in the comparative example.

[0034] Figure 7 A box plot showing the power conversion efficiency of perovskite cells formed according to a specific example of the present invention and a comparative example is shown.

[0035] Figure 8 It is a schematic diagram showing the cross-sectional structure of a perovskite cell formed in Example 2 according to the preparation method of the perovskite cell of the present invention.

[0036] Explanation of Figure Numbers

[0037] 111 Conductive substrate

[0038] 112 first hole transport layer

[0039] 113 First Perovskite Absorption Layer

[0040] 114 first interface passivation layer

[0041] 115 First electron transport layer

[0042] 116 First buffer layer

[0043] 117 first electrode layer

[0044] 121 Second hole transport layer

[0045] 122 Second perovskite light-absorbing layer

[0046] 123 Second interface passivation layer

[0047] 124 Second electron transport layer

[0048] 125 Second buffer layer

[0049] 126 second electrode layer

[0050] Steps S1 to S5 DETAILED DESCRIPTION

[0051] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0052] See also Figures 1 to 8 It should be noted that the diagrams provided in this embodiment are merely schematic illustrations of the basic concept of the present invention. Therefore, the diagrams only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0053] Example 1

[0054] The present invention provides a method for preparing a perovskite battery. Figure 1 , shown as a process flow diagram of the method, comprising the following steps:

[0055] S1: providing a conductive substrate, and forming a first hole transport layer on the conductive substrate;

[0056] S2: forming a first perovskite light absorbing layer on the first hole transport layer;

[0057] S3: mixing a piperazine carboxylic acid compound and an organic solvent in a preset ratio to form a passivation solution, coating the passivation solution on the surface of the first perovskite light-absorbing layer, and performing an annealing treatment to form a first interface passivation layer;

[0058] S4: forming a first electron transport layer on the first interface passivation layer;

[0059] S5: forming a first electrode layer on the first electron transport layer.

[0060] First, see Figure 2 , performing the step S1 : providing a conductive substrate 111 , and forming a first hole transport layer 112 on the conductive substrate 111 .

[0061] As an example, the conductive substrate 111 includes a rigid conductive substrate and a flexible conductive substrate.

[0062] As an example, the rigid conductive substrate includes any one of glass and metal plates.

[0063] As an example, the flexible conductive substrate includes a transparent conductive film layer and a transparent conductive oxide film layer located above the transparent conductive film layer. The transparent conductive film layer is made of at least one of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polydimethylsiloxane (PDMS), and polyimide (PI). The transparent conductive oxide film layer is made of at least one of indium tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium-doped zinc oxide (IZO), and indium cerium oxide (ICO). In this embodiment, the conductive substrate 111 is preferably a PET / ITO flexible conductive substrate.

[0064] As an example, before forming the first hole transport layer 112 on the conductive substrate 111 , the method further includes a step of pre-treating the conductive substrate 111 .

[0065] As an example, pre-treating the conductive substrate 111 includes the following steps:

[0066] (1) The conductive substrate 111 is placed in acetone, ethanol and deionized water in sequence for ultrasonic cleaning to remove oil-soluble impurities and water-soluble impurities on the conductive substrate 111.

[0067] (2) The conductive substrate 111 is subjected to UV-ozone treatment to further remove pollutants on the surface of the conductive substrate 111, while improving the surface properties of the conductive substrate 111, increasing the surface energy and hydrophilicity of the conductive substrate 111, and promoting the attachment of subsequent film layers.

[0068] As an example, forming the first hole transport layer 112 on the conductive substrate 111 includes the following steps:

[0069] (1) preparing a first hole transport precursor solution, and coating the first hole transport precursor solution on the conductive substrate 111;

[0070] (2) Performing annealing treatment to form the first hole transport layer 112 .

[0071] As an example, the material of the first hole transport layer 112 includes but is not limited to at least one of nickel oxide, [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz) and [4-(7H-dibenzocarbazole-7-yl)butyl]phosphonic acid (4PADCB).

[0072] As an example, the thickness of the first hole transport layer 112 is in the range of 5 to 30 nanometers.

[0073] Specifically, in this embodiment, the specific preparation method of the first hole transport precursor solution depends on the material composition of the first hole transport layer 112 to be formed. When the first hole transport layer 112 to be formed is composed of one material, such as when the first hole transport layer 112 to be formed is a nickel oxide layer, the first hole transport precursor solution can be formed by dissolving nickel oxide nanoparticles in deionized water or a suitable organic solvent; or, when the first hole transport layer 112 to be formed is a Me-4PACz layer, the first hole transport precursor solution can be formed by dissolving Me-4PACz powder in a suitable organic solvent (such as isopropyl alcohol, chloroform, etc.). When the first hole transport layer 112 to be formed is composed of two or more materials, the first hole transport precursor solution can be prepared by any of the following methods:

[0074] (a) Each material constituting the first hole transport layer 112 is prepared into a mixed solution, that is, the corresponding solutions or suspension solutions of each material constituting the first hole transport layer 112 are mixed together to form a composite first hole transport precursor solution.

[0075] (b) Each material constituting the first hole transport layer 112 is prepared into an independent solution, that is, each material constituting the first hole transport layer 112 corresponds to an independent solution, thereby forming the first hole transport precursor solution comprising multiple independent solutions. For such a first hole transport precursor solution comprising multiple independent solutions, in this embodiment, each of the independent solutions can be sequentially coated on the conductive substrate 111 by means of stacked coating, and after each independent solution is coated, an intermediate annealing treatment can be selectively performed to promote the bonding between layers and the solidification of the material. After the coating of the multiple independent solutions is completed, that is, after all layers are coated, a final annealing treatment is performed to form the first hole transport layer 112 comprising multiple material layers in a stacked arrangement.

[0076] As an example, the first hole transport precursor solution is applied to the conductive substrate 111 by at least one of spin coating, spray coating, printing, and blade coating. In this embodiment, the first hole transport precursor solution is preferably applied to the conductive substrate 111 by spin coating. The spin coating time ranges from 10 to 40 seconds, and the spin coating speed ranges from 1000 to 5000 rpm.

[0077] As an example, the temperature range of the annealing treatment is 100-150° C., and the time range of the annealing treatment is 5-30 minutes.

[0078] See also Figure 2 , performing the step S2: forming a first perovskite light absorbing layer 113 on the first hole transport layer 112 .

[0079] As an example, forming the first perovskite light absorbing layer 113 includes the following steps:

[0080] (1) A first perovskite precursor solution of a certain concentration is prepared, the first perovskite precursor solution is coated on the first hole transport layer 112, and the first perovskite precursor solution is subjected to an anti-solvent treatment.

[0081] (2) Perform annealing treatment.

[0082] As an example, the general structural formula of the material of the first perovskite light absorbing layer 113 is ABX3, where A is MA + , FA + 、Cs + Any one or a combination of at least two of the following, B is Pb 2+ 、Sn 2+ 、Ge 2+ Any one or a combination of at least two of - 、Cl - , I - Br - Any one or a combination of at least two of .

[0083] As an example, the thickness of the first perovskite light absorbing layer 113 is in the range of 300 to 800 nanometers.

[0084] As an example, the coating method for coating the first perovskite precursor solution on the first hole transport layer 112 includes any one of spraying, spin coating, drop coating, blade coating, roller coating, air knife coating, and brush coating. In this embodiment, the first perovskite precursor solution is preferably coated on the first hole transport layer 112 by spin coating, wherein the spin coating can be completed in one step or in two steps, and the spin coating time range is 30 to 80 seconds, and the spin coating speed range is 2000 to 8000 rpm.

[0085] Specifically, in this embodiment, an anti-solvent is added dropwise when the spin coating time is 5 to 35 seconds remaining, so as to perform anti-solvent treatment on the first perovskite precursor solution.

[0086] As an example, the anti-solvent includes any one of chlorobenzene, ethyl acetate, anisole, dimethyl ethyl carbonate, ethanol and diethyl ether.

[0087] As an example, the temperature range of the annealing treatment is 100-150° C., and the time range of the annealing treatment is 10-60 minutes.

[0088] In a specific example, forming the first perovskite light absorbing layer 113 includes the following steps: (1) dissolving methylammonium chloride (MACl), lead iodide (PbI2), cesium iodide (CsI) and methylammonium iodide (FAI) in a mixed solvent consisting of dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) in a volume ratio of 1:4, and stirring for 8 hours until the mixture is uniform, so as to form a FA solution with a concentration of 1.6 mol / mL. 0.95 Cs 0.05 PbI3 first perovskite precursor solution. (2) The FA is prepared in a one-step process. 0.95 Cs 0.05 A PbI3 first perovskite precursor solution was spin-coated onto the surface of the first hole transport layer 112. The spin-coating speed was 4000 rpm for 40 seconds. At the 33rd second mark of the spin-coating process, 200 μL of chlorobenzene was added dropwise for anti-solvent treatment. (3) An annealing treatment was performed at 100°C for 60 minutes to form the first perovskite light absorbing layer 113.

[0089] In another specific example, forming the first perovskite light absorbing layer 113 includes the following steps: (1) dissolving methylamine bromide (FABr), PbI2, CsI, FAI, cesium bromide (CsBr) and lead bromide (PbBr2) in a mixed solvent consisting of DMSO and DMF with a volume ratio of 1:4, and stirring at a temperature of 50° C. for 2 hours until the mixture is uniform, so as to form a FABr with a concentration in the range of 1.15 mol / mL. 0.8 Cs 0.2 PbI 1.95 Br 1.05 The first perovskite precursor solution. (2) The FA is prepared in two steps. 0.8 Cs 0.2 PbI 1.95 Br 1.05 The first perovskite precursor solution was spin-coated onto the surface of the first hole transport layer 112. The first step was spin-coating at 2000 rpm for 10 seconds, and the second step was spin-coating at 6000 rpm for 40 seconds. Twenty seconds before the end of the spin-coating, chlorobenzene was added dropwise to perform an anti-solvent treatment. (3) Annealing was performed at 100°C for 10 minutes to form the first perovskite light-absorbing layer 113.

[0090] It should be noted that the specific composition of the first perovskite light-absorbing layer 113 can be adjusted and optimized based on actual application needs to meet specific optoelectronic performance requirements. For example, to improve battery efficiency, a perovskite material with a wider bandgap can be selected, while a perovskite material containing tin can be selected to improve stability. Therefore, the preparation of the first perovskite precursor solution and the material composition of the subsequently formed first perovskite light-absorbing layer 113 are not fixed and can be adjusted based on actual application needs, and are not limited to the two examples above.

[0091] See also Figure 2 , perform step S3: mix the piperazine carboxylic acid compound and the organic solvent in a preset ratio to form a passivation treatment solution, apply the passivation treatment solution on the surface of the first perovskite light absorbing layer 113, and perform annealing treatment to form a first interface passivation layer 114.

[0092] Specifically, the passivation treatment solution is formed by mixing the piperazine carboxylic acid compound and the organic solvent in a preset ratio. The specific mixing ratio depends on the concentrations of the piperazine carboxylic acid compound and the organic solvent and is not limited here.

[0093] As an example, the piperazine carboxylic acid compound includes but is not limited to at least one of piperazine-DL-malate, 2-piperazineacetic acid and 4-piperazinebenzoic acid. In this embodiment, the piperazine carboxylic acid compound is preferably piperazine-DL-malate.

[0094] As an example, the organic solvent includes at least one of isopropyl alcohol, methanol, ethanol and ethyl acetate. In this embodiment, the organic solvent is preferably isopropyl alcohol.

[0095] Specifically, in this embodiment, the piperazine-DL-malate solid powder is added to the isopropanol solution, and the piperazine-DL-malate solid powder is evenly distributed in the isopropanol solution by continuous shaking and stirring, thereby preparing the desired passivation treatment solution.

[0096] As an example, the concentration range of the piperazine carboxylic acid compound in the passivation treatment solution is 0.1 to 2 mg / mL.

[0097] As an example, the passivation treatment liquid can be applied to the surface of the first perovskite light absorbing layer 113 by any one of spraying, spin coating, drip coating, blade coating, roller coating, air knife coating, and brush coating. In this embodiment, the passivation treatment liquid is preferably applied to the surface of the first perovskite light absorbing layer 113 by spin coating. The spin coating time ranges from 10 to 60 seconds, and the spin coating speed ranges from 1000 to 6000 rpm.

[0098] As an example, the temperature range of the annealing treatment performed after the passivation treatment solution is applied to the surface of the first perovskite light absorbing layer 113 is 100-150° C., and the time range of the annealing treatment is 5-30 seconds.

[0099] As an example, the thickness of the first interface passivation layer 114 is in the range of 1 to 15 nanometers.

[0100] Specifically, the first interface passivation layer 114 of this embodiment includes a piperazine group and a carboxylic acid group, wherein the nitrogen atom in the piperazine group and the oxygen atom in the carboxylic acid group can react with the metal cations (such as Pb) on the surface of the first perovskite light absorbing layer 113. 2+ This coordination effect can effectively passivate defects on the surface and grain boundaries of the first perovskite light absorbing layer 113, reduce the number of uncoordinated metal cation sites on the surface of the first perovskite light absorbing layer 113, thereby effectively suppressing non-radiative recombination and improving charge transfer efficiency.

[0101] Furthermore, the carboxylic acid groups in the first interface passivation layer 114 of this embodiment have a multi-point passivation effect. On the one hand, the hydroxyl groups in the carboxylic acid groups can form hydrogen bonds or weak electrostatic interactions with the iodine ions on the surface of the first perovskite light absorbing layer 113, thereby enhancing the adhesion of the first interface passivation layer 114 to the surface of the first perovskite light absorbing layer 113 and significantly reducing the defect state density on the surface of the first perovskite light absorbing layer 113. On the other hand, the protons (H + ) can be transferred to the alkaline sites on the surface of the first perovskite light-absorbing layer 113 to form carboxylate ions (-COO - ), the carboxylate ions can combine with the metal cations on the surface of the first perovskite light-absorbing layer 113 through electrostatic interaction, further enhancing the interface passivation effect, reducing non-radiative recombination, and effectively improving the stability of the first perovskite light-absorbing layer 113.

[0102] See also Figure 2 , performing step S4: forming a first electron transport layer 115 on the first interface passivation layer 114 .

[0103] As an example, the first electron transport layer 115 is formed by any one of thermal evaporation, sputtering, spraying, doctor blade coating and spin coating.

[0104] As an example, the material of the first electron transport layer 115 includes fullerene (C 60 ), at least one of a fullerene derivative (PCBM) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP).

[0105] As an example, the thickness of the electron transport layer is in the range of 5 to 50 nanometers.

[0106] See also Figure 2 , performing the step S5: forming a first electrode layer 117 on the first electron transport layer 115 .

[0107] As an example, a first buffer layer 116 is further formed between the first electron transport layer 115 and the first electrode layer 117 .

[0108] As an example, the first buffer layer 116 is formed by any one of atomic layer deposition, thermal evaporation, sputtering, doctor blading, spin coating, and spray coating.

[0109] As an example, the thickness of the first buffer layer 116 ranges from 5 to 100 nanometers.

[0110] As an example, the material of the first buffer layer 116 includes SnO x , where the value range of X is 1 to 2.

[0111] As an example, the first electrode layer 117 is formed by thermal evaporation, magnetron sputtering, chemical vapor deposition, atomic layer deposition or other suitable methods.

[0112] As an example, the material of the first electrode layer 117 includes any one of copper, silver, aluminum, nickel, gold and ITO.

[0113] At this point, a perovskite battery is produced.

[0114] In the preparation method of a perovskite battery provided in this embodiment, by introducing a first interface passivation layer 114 including a piperazine group and a carboxylic acid group into the first perovskite light absorbing layer 113 and the first electron transport layer 115, multiple optimizations of the first perovskite light absorbing layer 113 are achieved. The first interface passivation layer 114 not only effectively fills the grain boundary voids of the first perovskite light absorbing layer 113 and inhibits excessive crystal growth at the grain boundary, but also significantly reduces the roughness of the first perovskite surface. In addition, the first interface passivation layer 114 also effectively passivates the surface and grain boundary defects of the first perovskite light absorbing layer 113, reducing the impact of these defects on the charge transfer efficiency, thereby effectively inhibiting the occurrence of non-radiative recombination processes. In addition, the first interface passivation layer 114 also effectively regulates the energy level alignment between the first perovskite light absorbing layer 113 and the first electron transport layer 115, reduces charge accumulation, enhances charge transfer capability, and prolongs carrier lifetime, thereby significantly improving the overall performance of the perovskite battery.

[0115] The preparation method of the perovskite battery of the present invention is further introduced below with reference to a specific example and a comparative example.

[0116] In a specific example, the method for preparing the perovskite battery includes the following steps:

[0117] (1) First, a PET / ITO flexible conductive substrate with a length of 15 cm and a width of 15 cm was selected and ultrasonically cleaned in acetone, ethanol, and deionized water, respectively, for 20 minutes each, and then wiped clean. Subsequently, the PET / ITO flexible conductive substrate was subjected to UV-ozone treatment for 20 minutes to further clean and activate the surface of the PET / ITO flexible conductive substrate.

[0118] (2) Prepare a first hole transport precursor solution, which includes a first solution and a second solution. The first solution is obtained by dissolving nickel oxide nanoparticles in deionized water and performing ultrasonic treatment for 10 minutes, and its concentration is 10 mg / mL; the second solution is obtained by dissolving Me-4PACz in an isopropanol solution, and its concentration is 0.5 mg / mL. In this example, the process of forming the first hole transport layer 112 includes the following steps: first, the first solution is spin-coated on the surface of the PET / ITO flexible conductive substrate at a speed of 2000 rpm, and the spin coating duration is 20 seconds. Subsequently, annealing treatment is performed at a temperature of 100°C for 10 minutes to form a nickel oxide hole transport layer. Immediately thereafter, the second solution is spin-coated: the second solution is spin-coated on the formed nickel oxide hole transport layer at a speed of 3000 rpm, and the spin coating time is 30 seconds. Afterwards, an annealing treatment is performed at 100° C. for 10 minutes to form a Me-4PACz hole transport layer. Finally, the nickel oxide hole transport layer and the Me-4PACz hole transport layer together constitute the first hole transport layer 112 .

[0119] (3) MACl, PbI2, CsI and FAI were dissolved in a mixed solvent consisting of DMSO and DMF with a volume ratio of 1:4 and stirred for 8 hours until the mixture was uniform to form a FA solution with a concentration of 1.6 mol / mL. 0.95 Cs 0.05 The first perovskite precursor solution of PbI3 was prepared. Then, the FA was coated by a one-step spin coating method. 0.95 Cs 0.05The PbI3 first perovskite precursor solution was spin-coated onto the surface of the first hole transport layer 112 at 4000 rpm for 40 seconds. At the 33rd second mark of the spin-coating process, 200 μL of chlorobenzene was added dropwise for anti-solvent treatment. Finally, an annealing treatment was performed at 100°C for 60 minutes to form the first perovskite light-absorbing layer 113.

[0120] (4) Add piperazine-DL-malate to the isopropanol solution and shake and stir until the mixture is uniform, so as to form a piperazine-DL-malate passivation treatment solution with a concentration of 0.2 mg / mL. Then, the piperazine-DL-malate passivation treatment solution is spin-coated on the surface of the first perovskite light absorbing layer 113 at a speed of 3000 rpm for 30 seconds. Thereafter, annealing treatment is performed at a temperature of 100° C. for 10 minutes to form the first interface passivation layer 114. Figure 3 The figure shows a scanning electron microscope (SEM) image of this example after forming the first interface passivation layer 114 on the surface of the first perovskite light absorption layer 113. The grain size distribution of the first perovskite light absorption layer 113 is uniform and consistent, and the grains are closely arranged, forming a highly ordered crystalline morphology, indicating that the first interface passivation layer 114 helps promote uniform growth and crystallization of the grains. In addition, the introduction of the first interface passivation layer 114 significantly reduces the grain boundary voids, making the grain boundaries of the first perovskite light absorption layer 113 almost invisible, presenting a continuous and complete microstructure. This perovskite structure without grain boundary voids helps reduce the recombination rate of carriers and improve charge transfer efficiency.

[0121] (5) Using thermal evaporation method to prepare C on the first interface passivation layer 114 60 A thin film is formed to form the first electron transport layer 115. Then, SnO2 is deposited on the first electron transport layer 115 by atomic layer deposition to form the first buffer layer 116. Finally, a silver layer is deposited on the first buffer layer 116 by thermal evaporation as the first electrode layer 117 to prepare the perovskite cell, and the perovskite cell is a flexible perovskite cell. Figure 4 As shown in the figure, the power conversion efficiency (PCE) of the flexible perovskite battery is 21.13%, and the open circuit voltage (V OC ) is 1.10V, the short-circuit current (J SC ) is 24.75 mA / cm 2 , with a fill factor (FF) of 77.53%. In this example, the flexible perovskite battery formed is lightweight, bendable, and thin. It can also be integrated into clothing and even curved electronic devices, showing broad application prospects.

[0122] The preparation method of the perovskite battery in the comparative example is basically the same as the preparation method of the perovskite battery in a specific example of the present invention, except that the first interface passivation layer 114 is not introduced between the first perovskite light absorbing layer 113 and the first electron transport layer 115. Figure 5 As shown in FIG, a scanning electron microscope image is shown when the first interface passivation layer 114 is not formed on the surface of the first perovskite light absorbing layer 113 in the comparative example. It can be seen that the surface of the first perovskite light absorbing layer 113 is relatively rough, and the grain size distribution is uneven, in which larger grains coexist with smaller grains, resulting in poor overall crystallinity. In addition, there are obvious grain boundary voids on the surface of the first perovskite light absorbing layer 113, and these voids may become charge recombination centers, reducing the photoelectric conversion efficiency of the perovskite cell. Figure 6 As shown, the current density and voltage characteristic curve of the perovskite battery formed in the comparative example is shown, wherein the PCE of the perovskite battery is 19.83%, V OC is 1.07V, J SC 24.25 mA / cm 2 , FF is 75.98%. The performance of the perovskite battery formed in the comparative example is significantly lower than that of the perovskite battery formed in a specific example of the present invention. Figure 7 As shown, the power conversion efficiency of the perovskite cell formed in a specific example of the present invention is significantly higher than the power conversion efficiency of the perovskite cell formed in the comparative example.

[0123] Example 2

[0124] This embodiment provides a method for preparing a perovskite battery. The method for preparing a perovskite battery in this embodiment is basically the same as the method for preparing a perovskite battery in Example 1, except that it also includes a step of forming a bottom battery structure layer, and the bottom battery structure layer is formed on the surface of the first electrode layer 117.

[0125] As an example, the formation of the bottom battery structure layer includes the following steps:

[0126] (1) forming a second hole transport layer 121 on the first electrode layer 117;

[0127] (2) forming a second perovskite light absorbing layer 122 on the second hole transport layer 121, wherein the band gap width of the material of the second perovskite light absorbing layer 122 is smaller than the band gap width of the material of the first perovskite light absorbing layer 113;

[0128] (3) forming a second interface passivation layer 123 on the second perovskite light absorbing layer 122;

[0129] (4) forming a second electron transport layer 124 on the second interface passivation layer 123;

[0130] (5) Forming a second electrode layer 126 on the second electron transport layer 124 .

[0131] As an example, the material of the second hole transport layer 121 includes but is not limited to at least one of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), nickel oxide (NiO), cuprous thiocyanate (CuSCN) and poly(3-hexylthiophene) (P3HT).

[0132] As an example, forming the second hole transport layer 121 includes the following steps:

[0133] (1) Prepare a second hole transport precursor solution, and apply the second hole transport precursor solution on the first electrode layer 117 .

[0134] (2) Performing annealing treatment to form the second hole transport layer 121 .

[0135] Specifically, in this embodiment, the specific preparation method of the second hole transport precursor solution depends on the material composition of the second hole transport layer 121 to be formed. When the second hole transport layer 121 to be formed is composed of one material, such as when the second hole transport layer 121 to be formed is a PEDOT:PSS layer, the second hole transport precursor solution can be directly formed using a PEDOT:PSS aqueous suspension solution. Alternatively, if the second hole transport layer 121 to be formed is a nickel oxide layer, the second hole transport precursor solution can be formed by dissolving nickel oxide nanoparticles in deionized water or a suitable organic solvent. When the second hole transport layer 121 to be formed is composed of two or more materials, the second hole transport precursor solution can be prepared in any of the following ways:

[0136] (a) Each material constituting the second hole transport layer 121 is prepared into a mixed solution, that is, the solutions or suspensions corresponding to each material constituting the second hole transport layer 121 are mixed together to form a composite second hole transport precursor solution.

[0137] (b) Each material constituting the second hole transport layer 121 is prepared into an independent solution, that is, each material constituting the second hole transport layer 121 corresponds to an independent solution, thereby forming a second hole transport precursor solution comprising multiple independent solutions. For such a second hole transport precursor solution comprising multiple independent solutions, in this embodiment, each of the independent solutions can be sequentially coated on the first electrode layer 117 by means of a stacked coating method, and after each of the independent solutions is coated, an intermediate annealing treatment can be selectively performed to promote the bonding between the layers and the solidification of the materials. After the coating of the multiple independent solutions is completed, that is, after all layers are coated, a final annealing treatment is performed to form a stacked arrangement of the second hole transport layer 121 comprising multiple material layers.

[0138] As an example, the second hole transport precursor solution is applied to the first electrode layer 117 by any one of spray coating, spin coating, drop coating, doctor blade coating, roller coating, and air knife coating. In this embodiment, the second hole transport precursor solution is preferably applied to the first electrode layer 117 by spin coating.

[0139] As an example, the temperature range of the annealing treatment is 50-150° C., and the time range of the annealing treatment is 5-15 minutes.

[0140] In one specific example, the process of forming the second hole transport layer 121 includes preparing a PEDOT:PSS solution, spin-coating the PEDOT:PSS solution onto the first electrode layer 117 at 4000 rpm for 30 seconds, and then performing an annealing treatment in air at 100°C for 10 minutes to form the second hole transport layer 121.

[0141] As an example, forming the second perovskite light absorbing layer 122 includes the following steps:

[0142] (1) A second perovskite precursor solution of a certain concentration is prepared, the second perovskite precursor solution is coated on the second hole transport layer 121, and the second perovskite precursor solution is subjected to an anti-solvent treatment.

[0143] (2) Perform annealing treatment.

[0144] As an example, the structural formula of the material of the second perovskite light absorbing layer 122 is ABX3, where A is MA + , FA + 、Cs + Any one or a combination of at least two of the following, B is Pb 2+ 、Sn 2+ 、Ge2+ Any one or a combination of at least two of - 、Cl - , I - Br - Any one or a combination of at least two of .

[0145] As an example, the concentration range of the second perovskite precursor solution is 1 to 3 mol / mL.

[0146] As an example, the coating method of applying the second perovskite precursor solution to the second hole transport layer 121 includes any one of spraying, spin coating, drop coating, blade coating, roller coating, air knife coating, and brush coating. In this embodiment, the second perovskite precursor solution is preferably coated on the second hole transport layer 121 by spin coating, and the spin coating is completed in two steps, wherein the first spin coating time range is 5 to 15 seconds, the first spin coating speed range is 500 to 1500 rpm, and the second spin coating time range is 20 to 60 seconds, and the second spin coating speed range is 3000 to 5000 rpm.

[0147] Specifically, in this embodiment, an anti-solvent is added dropwise when the spin coating time is 5 to 15 seconds remaining to perform an anti-solvent treatment on the second perovskite precursor solution. The anti-solvent used in the anti-solvent treatment of the second perovskite precursor solution is the same as the anti-solvent used in the anti-solvent treatment of the first perovskite precursor solution.

[0148] As an example, the temperature range of the annealing treatment performed after the anti-solvent treatment of the second perovskite precursor solution is 50-150° C., and the time range of the annealing treatment is 5-10 minutes.

[0149] In a specific example, forming the second perovskite light absorbing layer 122 includes the following steps: (1) dissolving lead iodide (PbI2), methylammonium iodide (MAI), FAI and stannous iodide (SnI2) in a mixed solvent consisting of DMSO and DMF with a volume ratio of 1:2, and stirring at room temperature for 2 hours until the mixture is uniform, so as to form a FAI solution with a concentration of 1.8 mol / mL. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 second perovskite precursor solution. (2) The FA is prepared by a two-step method. 0.7 MA 0.3 Pb 0.5 Sn 0.5The second perovskite precursor solution (I3) was spin-coated onto the surface of the second hole transport layer 121. The first step was spin-coating at 1000 rpm for 10 seconds, and the second step was spin-coating at 4000 rpm for 40 seconds. Chlorobenzene was added dropwise 10 seconds before the end of the spin-coating process to perform an anti-solvent treatment. (3) Annealing was performed at 100°C for 10 minutes to form the second perovskite light-absorbing layer 122.

[0150] As an example, the process of forming the second interface passivation layer 123 includes: preparing a passivation solution, coating the passivation solution on the second perovskite absorption layer 122, and performing annealing treatment to form the second interface passivation layer 123, wherein the composition of the passivation solution used to form the second interface passivation layer 123 is the same as or different from the composition of the passivation treatment solution used to form the first interface passivation layer 114.

[0151] Specifically, when the composition of the passivation solution used to form the second interface passivation layer 123 is the same as the composition of the passivation treatment solution used to form the first interface passivation layer 114, that is, when the passivation solution is composed of the piperazine carboxylic acid compound and the organic solvent mixed in a specific proportion, the material of the formed second interface passivation layer 123 includes at least one of piperazine-DL-malate, 2-piperazineacetic acid and 4-piperazinebenzoic acid.

[0152] Specifically, when the composition of the passivation solution used to form the second interface passivation layer 123 is different from the composition of the passivation treatment solution used to form the first interface passivation layer 114, the material of the formed second interface passivation layer 123 includes at least one of ethylenediamine dihydroiodide (EDAI), 1,3-diaminopropane dihydroiodide (PDADI), 4-methoxyphenethylammonium iodide (PEAI), phenethylammonium bromide (PEABr) and 4-trifluoromethylphenethylammonium chloride (CF3-PEACl), wherein the specific composition of the passivation solution is selected according to the actual thickness of the second interface passivation layer 123 to be formed, the passivation effect, etc.

[0153] As an example, the passivation solution is coated on the second perovskite light absorbing layer 122 by any one of spray coating, spin coating, drop coating, doctor blade coating, roller coating, air knife coating and brush coating.

[0154] As an example, the temperature range of the annealing treatment performed after the passivation solution is coated on the second perovskite light absorbing layer 122 is 50-150°C.

[0155] In one specific example, the process of forming the second interface passivation layer 123 includes adding piperazine-DL-malate to an isopropyl alcohol solution and stirring the mixture until uniformly mixed, thereby forming a piperazine-DL-malate passivation solution with a concentration of 0.2 mg / mL. Next, the piperazine-DL-malate passivation solution is spin-coated onto the surface of the second perovskite light-absorbing layer 122 at a speed of 3000 rpm for 30 seconds. Subsequently, an annealing treatment is performed at 100°C for 10 minutes to form the second interface passivation layer 123.

[0156] In another specific example, the process of forming the second interface passivation layer 123 includes: adding EDAI to an isopropyl alcohol solution and stirring until the mixture is uniform to form an EDAI passivation solution with a concentration of 0.5 mg / mL; the EDAI passivation solution is spin-coated on the second perovskite light absorbing layer 122 at a speed of 4000 rpm for 30 seconds; and then performing an annealing treatment at a temperature of 100° C. for 10 minutes to form the second interface passivation layer 123.

[0157] Of course, in other examples, the second interface passivation layer 123 may also be prepared from the passivation solution containing other material components, which is not specifically limited here.

[0158] As an example, the second electron transport layer 124 is formed by thermal evaporation, atomic layer deposition, spin coating, doctor blade coating, slit deposition, spray coating, chemical bath deposition, or other suitable methods.

[0159] As an example, the material of the second electron transport layer 124 includes PCBM, C 60 , any one of tin dioxide, titanium oxide and zinc oxide.

[0160] In a specific example, a 25 mg / ml PCBM solution is spin-coated on the second interface passivation layer 123 at a rotation speed of 2000 rpm for 30 seconds to form the second electron transport layer 124 .

[0161] As an example, a second buffer layer 125 is further formed between the second electron transport layer 124 and the second electrode layer 126 .

[0162] As an example, the second buffer layer 125 can be formed by any of blade coating, spin coating, spray coating, atomic layer deposition, thermal evaporation, and sputtering. In this embodiment, the second buffer layer 125 is preferably formed by spin coating. The spin coating time ranges from 10 to 50 seconds, and the spin coating speed ranges from 2000 to 6000 rpm.

[0163] As an example, the material of the second buffer layer 125 includes at least one of BCP, lithium fluoride (LiF), and cesium carbonate (Cs 2 CO 3 ).

[0164] In a specific example, a supersaturated BCP solution is spin-coated on the second electron transport layer 124 at a rotation speed of 4000 rpm for 30 seconds, and annealed at a temperature of 100° C. for 1 minute to form the second buffer layer 125 .

[0165] As an example, the second electrode layer 126 is formed by thermal evaporation, magnetron sputtering, chemical vapor deposition, atomic layer deposition or other suitable methods.

[0166] As an example, the material of the second electrode layer 126 includes any one of copper, silver, aluminum, nickel, gold and ITO.

[0167] In a specific example, a silver layer is deposited on the second buffer layer 125 by thermal evaporation to form the second electrode layer 126 .

[0168] At this point, a perovskite battery structure is produced, such as Figure 8 shown.

[0169] In a method for preparing a perovskite cell of this embodiment, an underlying cell structure layer is formed on the surface of the first electrode layer 117, thereby achieving optimized superposition of perovskite layers with different band gaps, effectively expanding the spectral absorption range of the perovskite cell, and forming an efficient stacked perovskite cell structure. In the stacked perovskite battery structure, in addition to introducing a first interface passivation layer 114 including a piperazine group and a carboxylic acid group into the first perovskite light absorption layer 113 and the first electron transport layer 115 to achieve multiple optimizations of the first perovskite light absorption layer 113, a second interface passivation layer 123 is also introduced between the second perovskite light absorption layer 122 and the second electron transport layer 124 in the bottom battery structure layer, and the second interface passivation layer 123 can also be formed using a material including a piperazine group and a carboxylic acid group to further remove surface and grain boundary defects of the second perovskite light absorption layer 122, inhibit non-radiative recombination, and at the same time regulate the energy level alignment between the second perovskite light absorption layer 122 and the first electron transport layer 115, reduce charge accumulation, enhance charge transport capability, and extend carrier lifetime, thereby improving the overall performance of the stacked perovskite battery structure. It should be noted that, Figure 8 The structural order in the figure is shown for reference only and should be reversed in actual application, that is, the bottom battery structure layer should be located at the bottom.

[0170] Example 3

[0171] This embodiment provides a perovskite cell structure, comprising a conductive substrate 111, a first hole transport layer 112, a first perovskite light absorption layer 113, a first interface passivation layer 114, a first electron transport layer 115, and a first electrode layer 117 stacked in sequence. The perovskite cell structure is obtained using the perovskite cell preparation method of any one of Embodiments 1 and 2. The perovskite cell structure of this embodiment achieves multiple optimizations of the first perovskite light absorption layer 113 by introducing a first interface passivation layer 114 comprising piperazine groups and carboxylic acid groups between the first perovskite light absorption layer 113 and the first electron transport layer 115. The first interface passivation layer 114 not only effectively passivates the defects on the surface and grain boundaries of the first perovskite light-absorbing layer 113 and suppresses the occurrence of non-radiative recombination processes, but also effectively regulates the energy level alignment between the first perovskite light-absorbing layer 113 and the first electron transport layer 115, thereby enhancing the charge transfer capability and extending the carrier lifetime, thereby significantly improving the overall performance of the perovskite battery.

[0172] In summary, the present invention provides a method and structure for preparing a perovskite cell, which achieves a significant improvement in the performance of the perovskite cell by introducing a specific interface passivation layer between the first perovskite light-absorbing layer and the first electron transport layer. The introduction of the interface passivation layer effectively passivates the defects on the surface of the first perovskite light-absorbing layer and at its grain boundaries, and reduces the interface defect state density between the first perovskite light-absorbing layer and the first electron transport layer, thereby effectively suppressing the occurrence of non-radiative recombination processes. In addition, the interface passivation layer also optimizes the band structure of the first perovskite light-absorbing layer, significantly improves the carrier extraction efficiency, and thus greatly improves the overall performance of the perovskite solar cell. The preparation method of the present invention is simple and efficient, can significantly improve the overall performance of the perovskite cell, and can be widely used in photovoltaic power generation, photoelectric detection and other fields. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0173] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A method for preparing a perovskite battery, characterized in that: The following steps are involved: Providing a conductive substrate, and forming a first hole transport layer on the conductive substrate; forming a first perovskite light absorbing layer on the first hole transport layer; Mixing a piperazine carboxylic acid compound and an organic solvent in a preset ratio to form a passivation solution, applying the passivation solution to the surface of the first perovskite light-absorbing layer, and performing an annealing treatment to form a first interface passivation layer; forming a first electron transport layer on the first interface passivation layer; A first electrode layer is formed on the first electron transport layer.

2. The method for preparing a perovskite battery according to claim 1, wherein: The piperazine carboxylic acid compound includes at least one of piperazine-DL-malate, 2-piperazineacetic acid and 4-piperazinebenzoic acid.

3. The method for preparing a perovskite battery according to claim 1, wherein: The concentration range of the piperazine carboxylic acid compound in the passivation treatment solution is 0.1-2 mg / mL.

4. The method for preparing a perovskite battery according to claim 1, wherein: The thickness of the first interface passivation layer is in the range of 1 to 15 nanometers.

5. The method for preparing a perovskite battery according to claim 1, wherein: The organic solvent includes at least one of isopropyl alcohol, methanol, ethanol and ethyl acetate.

6. The method for preparing a perovskite battery according to claim 1, wherein: The general structural formula of the material of the first perovskite light absorbing layer is ABX3, wherein A is MA + , FA + 、Cs + Any one or a combination of at least two of the following, B is Pb 2+ 、Sn 2+ 、Ge 2+ Any one or a combination of at least two of - 、Cl - , I - Br - Any one or a combination of at least two of .

7. The method for preparing a perovskite battery according to claim 1, wherein: The method further includes forming a bottom battery structure layer, wherein the bottom battery structure layer is formed on the surface of the first electrode layer.

8. The method for preparing a perovskite battery according to claim 7, wherein: The formation of the bottom battery structure layer comprises the following steps: forming a second hole transport layer on the first electrode layer; forming a second perovskite light absorption layer on the second hole transport layer, wherein the band gap of the material of the second perovskite light absorption layer is smaller than the band gap of the material of the first perovskite light absorption layer; forming a second interface passivation layer on the second perovskite light absorbing layer; forming a second electron transport layer on the second interface passivation layer; A second electrode layer is formed on the second electron transport layer.

9. The method for preparing a perovskite battery according to claim 8, wherein: The process of forming the second interface passivation layer includes: preparing a passivation solution, coating the passivation solution on the second perovskite light-absorbing layer, and performing annealing treatment to form the second interface passivation layer, wherein the composition of the passivation solution used to form the second interface passivation layer is the same as or different from the composition of the passivation treatment solution used to form the first interface passivation layer.

10. A perovskite battery structure, characterized in that: The perovskite cell structure includes a conductive substrate, a first hole transport layer, a first perovskite light absorption layer, a first interface passivation layer, a first electron transport layer and a first electrode layer stacked in sequence, wherein the perovskite cell structure is obtained by the preparation method of the perovskite cell according to any one of claims 1 to 9.

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