Selective charge transport layer, precursor liquid, perovskite battery and preparation method thereof

Abstract

The invention discloses a selective charge transport layer, a precursor liquid, a perovskite cell and a preparation method thereof, and relates to the technical field of solar cells, the selective charge transport layer is used for a solar cell, and comprises a high-molecular polymer as a parent material, a selective charge transport polymer doped in the parent material, and / or a selective charge transport polymer doped in the parent material. A copolymer formed by the high-molecular polymer and the selective charge transport polymer; wherein the selective charge transport polymer transports electrons or holes; and the molecular weight of the high-molecular polymer is greater than 10000. According to the selective charge transport layer, the perovskite cell and the preparation method of the perovskite cell provided by the invention, the use amount of the material of the selective charge transport layer can be reduced on the basis of ensuring the transport effect of the selective charge transport layer.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a selective charge transport layer, a precursor liquid, a perovskite cell and a preparation method thereof. Background Art

[0002] Since its invention in 2009, perovskite solar cells have seen rapid efficiency improvements, demonstrating the enormous potential of next-generation commercial solar cells. Perovskite solar cells typically consist of five components: transparent conductive glass, an electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a metal back electrode. The hole transport layer, typically 0-150nm thick, collects holes injected from the perovskite light-absorbing layer and separates the charge of electron-hole pairs in the perovskite light-absorbing layer. Perovskite solar cells without a hole transport layer typically have relatively low photoelectric conversion efficiency. Inserting a hole transport material between the perovskite light-absorbing layer and the metal back electrode can improve the Schottky contact, promote the separation of electrons and holes at the interface of the functional layer, reduce charge recombination, and adjust energy level matching, contributing to higher photoelectric conversion efficiency.

[0003] In 2012, 2,2′,7,7′-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD) was first used as a hole transport material in perovskite solar cells, achieving high photoelectric conversion efficiency. Currently, newly developed hole transport materials are often compared with spiro-OMeTAD. Although spiro-OMeTAD can achieve high photoelectric conversion efficiency as a hole transport material, its high unit price makes the selective charge transport layer of perovskite solar cells expensive, limiting the commercial application of perovskite solar cells. Summary of the Invention

[0004] The purpose of this application is to provide a selective charge transport layer, a perovskite battery and a preparation method thereof, which can reduce the amount of selective charge transport layer material while ensuring the transport effect of the selective charge transport layer.

[0005] On the one hand, an embodiment of the present application provides a selective charge transport layer, which is used for a solar cell and includes a high molecular weight polymer as a matrix material, a selective charge transport polymer doped in the matrix material, and / or a copolymer formed by the high molecular weight polymer and the selective charge transport polymer; wherein the selective charge transport polymer transports electrons or holes; and the molecular weight of the high molecular weight polymer is greater than 10,000.

[0006] As an practicable manner, the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 1:4 and 4:1. Preferably, the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 2:3 and 3:2.

[0007] As an practicable manner, the high molecular polymer is one or more combinations of cross-linked polydimethylsiloxane, polymethyl methacrylate, polyvinyl pyrrolidone, poly-4-ethylphenol, polybutylene terephthalate, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polylactic acid, polyformaldehyde, polyamide, polyimide, polyethyleneimine, polydopamine, polyvinylidene fluoride, polyacrylonitrile, or one or more copolymers.

[0008] As an practicable embodiment, the selective charge transport polymer is a polymer hole transport material used in a hole transport layer, or a polymer electron transport material used in an electron transport layer.

[0009] As an practicable manner, the polymer hole transport material is a combination of one or more of PTAA, polyTPD, P3HT, PEDOT, EDOT:PSS, PANI, or one or more derivatives thereof; the polymer electron transport material includes a combination of one or more of N2200, N2300, N-CS2DPP-OD-TEG, P-BNBP-T, P-IFDMT4, or one or more derivatives thereof.

[0010] As an practicable approach, the high molecular weight polymer contains a coordination group for passivating defects in the perovskite film; optionally, the coordination group includes one or more of an amino group, a carboxyl group, a hydroxyl group, a benzene ring, and a sulfonic acid group.

[0011] As an practicable manner, the selective charge transport layer is further doped with an additive for improving carrier mobility, and the additive may include Li-TFSI and Tbp.

[0012] Another aspect of an embodiment of the present application provides a precursor liquid for preparing a selective charge transport layer, comprising a polymer, a selective charge transport polymer, and / or a copolymer formed by the polymer and the selective charge transport polymer, and a solvent, wherein the selective charge transport polymer utilizes electrons or holes to transport charges; and the molecular weight of the polymer is greater than 10,000.

[0013] As an practicable manner, the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 1:4 and 9:1. Preferably, the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 2:3 and 3:2.

[0014] As an practicable manner, the high molecular polymer is a combination of one or more of cross-linked polydimethylsiloxane, polymethyl methacrylate, polyvinyl pyrrolidone, poly-4-ethylphenol, polybutylene terephthalate, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polyvinyl alcohol, polylactic acid, polycarbonate, polyacrylic acid, plastic starch material, polysulfone, polyurethane, polyformaldehyde, polyamide, polyimide, polyamideimide, polyethyleneimine, polydopamine, polyvinylidene fluoride, polyacrylonitrile, polyetheretherketone, epoxy resin and ABS resin, or one or more copolymers.

[0015] As an practicable manner, the precursor liquid includes polyTPD, PMMA and PTAA, and the mass concentration ratio of the three is 3:4:3.

[0016] In another aspect of the embodiments of the present application, a perovskite cell is provided, comprising a perovskite film layer and any one of the selective charge transport layers described above.

[0017] Another aspect of the embodiments of the present application provides a method for preparing a perovskite battery, including a preparation process for a selective charge transport layer, the preparation process for the selective charge transport layer comprising: coating a substrate with a precursor liquid of the selective charge transport layer described in any one of the above items to form a selective charge transport layer, the selective charge transport layer comprising a high molecular weight polymer as a matrix material, and a selective charge transport polymer doped in the matrix material, and / or a copolymer formed by the high molecular weight polymer and the selective charge transport polymer.

[0018] The beneficial effects of the embodiments of the present application include:

[0019] The selective charge transport layer provided in the present application is used in a solar cell and includes a polymer as a matrix material, a selective charge transport polymer doped in the matrix material, and / or a copolymer formed by the polymer and the selective charge transport polymer. The selective charge transport polymer is used to transport electrons or holes. When the selective charge transport polymer transports holes, the selective charge transport layer serves as a hole transport layer of the perovskite cell; when the selective charge transport polymer transports electrons, the selective charge transport layer serves as an electron transport layer of the perovskite cell. The molecular weight of the polymer is greater than 10,000. When the polymer is set as the matrix material, the amount of the selective charge transport polymer can be reduced, while the coating property of the material is increased to facilitate film formation. Therefore, the present application reduces the amount of the selective polymer without affecting (or substantially affecting) the function of the selective charge transport layer. Existing perovskite selective charge transport polymers are expensive (18K / g), while the price of the polymer is greatly reduced compared to that of the selective charge transport polymer, and its cost is basically negligible. Therefore, when the amount of the selective charge transport polymer is reduced, the cost of the selective charge transport layer is reduced. If the present application solution is used for perovskite batteries, the cost can be reduced to 50% of the original cost based on the hole transport layer of the perovskite battery.

[0020] In addition, for perovskite batteries, adding high molecular weight polymers to the selective charge transport layer can also improve the wettability of the perovskite solution relative to the selective charge transport layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 This is one of the structural schematic diagrams of a perovskite battery provided in an embodiment of the present application;

[0023] Figure 2 This is a flow chart of a method for preparing a perovskite battery provided in an embodiment of the present application;

[0024] Figure 3 This is a second structural diagram of a perovskite battery provided in an embodiment of the present application;

[0025] Figure 4 This is a second flow chart of a method for preparing a perovskite battery provided in an embodiment of the present application;

[0026] Figure 5 The third structural diagram of a perovskite battery provided in an embodiment of the present application;

[0027] Figure 6 This is one of the performance comparison diagrams of multiple embodiments provided in the embodiments of this application;

[0028] Figure 7 The second performance comparison diagram of multiple embodiments provided in the embodiments of this application;

[0029] Figure 8 The third performance comparison diagram of multiple embodiments provided in the embodiments of this application;

[0030] Figure 9 The fourth performance comparison diagram of multiple embodiments provided in the embodiments of this application;

[0031] Figure 10 Wettability contact angle test diagram of comparative example;

[0032] Figure 11 Wettability contact angle test diagram of an embodiment of the present application.

[0033] Icons: 10-perovskite cell; 11-perovskite film layer; 12-hole transport layer; 13-electron transport layer; 14-crystalline silicon bottom cell; 16-electrode; 17-transparent conductive layer. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0037] Selective charge transport layer: The selective charge transport layer can selectively transport electrons or holes. The selective charge transport layer includes a hole transport layer and an electron transport layer, and is a basic functional layer in solar cells.

[0038] For example, the hole transport layer of a perovskite solar cell is typically made of polymer materials, such as PTAA, polyTPD, P3HT, or PEDOT:PSS. However, the high cost of preparing these polymers is a significant constraint on their industrial application. Polymerization of these polymers is difficult, making it challenging to achieve a high degree of polymerization. A higher degree of polymerization allows for better substrate coverage during wet processing, helping the cell mitigate short-circuit conditions.

[0039] To solve the above problems, an embodiment of the present application provides a selective charge transport layer, which is used for a solar cell and includes a high molecular weight polymer as a matrix material and a selective charge transport polymer doped in the matrix material, wherein the selective charge transport polymer transports electrons or holes; the molecular weight of the high molecular weight polymer is greater than 10,000.

[0040] In another embodiment, a selective charge transport layer is provided, comprising a high molecular weight polymer as a matrix material, a selective charge transport polymer doped in the matrix material, and a copolymer formed by the high molecular weight polymer and the selective charge transport polymer; wherein the selective charge transport polymer transports electrons or holes; and the molecular weight of the high molecular weight polymer is greater than 10,000.

[0041] In another embodiment, a selective charge transport layer is provided, comprising a copolymer formed by a high molecular weight polymer and a selective charge transport polymer; wherein the portion of the copolymer corresponding to the selective charge transport polymer transports electrons or holes; and the molecular weight of the high molecular weight polymer is greater than 10,000.

[0042] The selective charge transport layer mentioned above refers to the hole transport layer or electron transport layer in a solar cell. A selective charge transport polymer refers to a currently disclosed or undisclosed polymer material that can function as a hole transport layer or electron transport layer. In this application, a polymer material that can function as a hole transport layer is also referred to as a polymer hole transport material; a polymer material that can function as an electron transport layer is also referred to as a polymer electron transport material.

[0043] The selective charge transport layer provided in the embodiment of the present application can be used in the perovskite battery 10, specifically, Figure 1As shown, the perovskite cell 10 includes a perovskite film layer 11 and a hole transport layer 12 and an electron transport layer 13 arranged on both sides of the perovskite film layer 11. When the perovskite film layer 11 is irradiated by sunlight, the material in the perovskite film layer 11 absorbs photons to generate electron-hole pairs. The electron-hole pairs are separated into electrons and holes in the perovskite film layer 11. The electrons are collected by the electron transport layer 13 and the holes are collected by the hole transport layer 12, thereby realizing the conversion of light energy into electrical energy.

[0044] Specifically, the selective charge transport layer of the embodiment of the present application selectively transports electrons or holes, that is, the selective charge transport layer provided in the embodiment of the present application can be the electron transport layer 13 or the hole transport layer 12 of the perovskite battery 10. The solution of the present application can be used for the electron transport layer of a perovskite battery, and can also be used for the hole transport layer of a perovskite battery, or can be used for both the electron transport layer and the hole transport layer of a perovskite battery. Perovskite batteries refer to single-junction or multi-junction batteries that include a perovskite film layer as a light-absorbing layer. In this article, perovskite batteries include at least: perovskite single-junction batteries, perovskite crystalline silicon stacked batteries, full perovskite stacked batteries, and other batteries that include at least one perovskite film layer as a light-absorbing layer.

[0045] Experimental data shows that the transfer efficiency of the selective charge transport layer comprising a polymer does not decrease. Furthermore, the selective charge transport layer comprising a polymer reduces the amount of the selective charge transport polymer used. Therefore, the selective charge transport layer of the embodiments of the present application can reduce the amount of the selective charge transport polymer used while maintaining transfer efficiency. The selective charge transport polymer costs around ¥18,000 per gram, while the cost of the polymer is relatively negligible. Reducing the amount of the selective charge transport polymer significantly reduces the cost of the selective charge transport layer.

[0046] Furthermore, the molecular weight of the high molecular weight polymer is greater than 10,000. High molecular weight polymers are readily available and relatively easy to prepare. When the selective charge transport layer comprises a high molecular weight polymer, the coating performance of the material is enhanced, and the molecular weight requirement for the selective charge transport polymer is reduced. This can, to a certain extent, reduce the difficulty of preparing the selective charge transport polymer (larger molecular weights generally increase the synthesis difficulty).

[0047] In summary, by adopting the solution of the present application, since a high molecular weight polymer is added to the raw materials for preparing the selective charge transport layer, the dosage and molecular weight requirements of the selective charge transport polymer are reduced, and at the same time, the coating performance of the raw materials is increased, thereby reducing the difficulty of preparing the selective charge transport layer.

[0048] In some embodiments, the polymer has a higher molecular weight than the selective charge transport polymer, allowing for better substrate coating. In other embodiments, because the polymer and the selective charge transport polymer form a copolymer, they can also better coat the substrate during a wet process, thereby reducing the probability of short circuits in the battery.

[0049] The present application does not limit the specific materials of the high molecular weight polymer and the transport polymer in the embodiments of the present application. Those skilled in the art can select specific high molecular weight polymer and selective charge transport polymer materials according to actual conditions.

[0050] The selective charge transport layer provided herein can be the electron transport layer 13 or the hole transport layer 12 in a solar cell. The selective charge transport layer comprises a polymer as a matrix material and a selective charge transport polymer doped into the matrix material; or the selective charge transport layer comprises a copolymer formed by copolymerizing a selective charge transport polymer with a polymer; or the selective charge transport layer comprises a selective charge transport polymer, a polymer, and a copolymer. The selective charge transport polymer and the corresponding portion of the copolymer transport electrons or holes.

[0051] Taking perovskite cells as an example, when the selective charge transport polymer transports holes, the selective charge transport layer can serve as the hole transport layer 12 of the perovskite cell 10; when the selective charge transport polymer transports electrons, the selective charge transport layer serves as the electron transport layer 13 of the perovskite cell 10.

[0052] The molecular weight of the polymer is greater than 10,000. When used as the matrix material, the amount of the selective charge transport polymer can be reduced, significantly reducing costs. The current price of the selective charge transport polymer is around 18,000 yuan per gram, making the cost of the polymer essentially negligible compared to the selective charge transport polymer.

[0053] In some embodiments, the high molecular polymer is a continuous phase in the selective charge transport layer, and the selective charge transport polymer is doped therein. The selective charge transport polymer can transport electrons or holes.

[0054] In other embodiments, the selective charge transport layer is a copolymer film layer formed by a high molecular polymer and a selective charge transport polymer, and the partial structure of the copolymer corresponding to the selective charge transport polymer still has the function of transporting electrons or holes.

[0055] In other embodiments, the high molecular weight polymer serves as the continuous phase, interspersed with some selective charge transport polymers and the above-mentioned copolymers.

[0056] Optionally, the mass ratio of the polymer to the selective charge transport polymer is between 1:4 and 9:1, which can minimize the amount of the selective charge transport polymer while ensuring the transport effect. Furthermore, preferably, when the mass ratio of the polymer to the selective charge transport polymer is between 2:3 and 3:2, the corresponding perovskite cell performance parameters are better.

[0057] Preferably, the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 2:3 and 3:2, for example, 2:3, 1:1, 3:2, etc., and more preferably, 1:1.

[0058] In the above-mentioned mass ratios of the high molecular weight polymer to the selective charge transport polymer, the mass ratios are understood to refer to the mass ratios of the respective raw materials in the precursor solution used to prepare the selective charge transport layer. If a copolymer is present in the selective charge transport layer, the mass ratios of the high molecular weight polymer to the selective charge transport polymer are calculated by including the equivalent mass of the copolymer in the mass ratios of the high molecular weight polymer to the selective charge transport polymer.

[0059] If only the copolymer exists in the selective charge transport layer, and the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 1:4-9:1, it means that the mass ratio of the high molecular weight polymer used to prepare the copolymer to the selective charge transport polymer is between 1:4-9:1.

[0060] In some embodiments, the selective charge transport polymer is a polymer hole transport material used in the hole transport layer 12. In other embodiments, the selective charge transport polymer is a polymer electron transport material used in the electron transport layer 13.

[0061] Illustratively, the above-mentioned polymer hole transport material can be a combination of one or more of PTAA, polyTPD, P3HT, PEDOT, EDOT:PSS, PANI, or one or more derivatives thereof; the polymer electron transport material can include a combination of one or more of N2200, N2300, N-CS2DPP-OD-TEG, P-BNBP-T, P-IFDMT4 / , or one or more derivatives thereof.

[0062]

[0063]

[0064] The derivatives can be, for example, N2200, X=S and PNDIBS, X=Se, or PNDIF-T2, PNBSF, PNDIV-BT, P4, 30PDI, NOE10 (X=0.1) and PNDI0.5 (X=0.5), P(NDI20D-TZ2), TEG-N2200, PNDIT-F3N, PDI-V, PDTZTI, PBIT1, f-BIT2-FT, f-BIT2-T or PTZBITT.

[0065] The materials and ratios of the polymer hole transport material are not specifically limited in the embodiments of this application, and those skilled in the art can select one, two, or three of the above materials. Similarly, the materials and ratios of the polymer electron transport material are not limited in the embodiments of this application, and those skilled in the art can select one, two, or three of the above materials.

[0066] In one achievable embodiment of the present application, the high molecular polymer in the selective charge transport layer is a combination of one or more of cross-linked polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polyvinyl pyrrolidone (PVP), poly-4-ethylphenol (POLY), polyethylene terephthalate (PET), polystyrene (PS), polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polylactic acid (PLA), polyoxymethylene (POM), polyamide (PA), polyimide (PI), polyethyleneimine, polydopamine, polyvinylidene fluoride (PVDF), and polyacrylonitrile (PAN), or one or more copolymers thereof.

[0067] Specifically, the materials and ratios of the high molecular polymers are not specifically limited in the embodiments of the present application, and those skilled in the art can select one, two or three of the above materials.

[0068] In another possible implementation of the present invention, a selective charge transport layer is provided, which is made of one (or more) of the above-listed high molecular weight polymers and one (or more) of the above-listed selective charge transport polymers. Furthermore, the raw materials for preparing the selective charge transport layer may or may not contain a copolymer of the two.

[0069] In another achievable embodiment of the present application, a selective charge transport layer is provided, which is made of a copolymer, wherein the copolymer is formed by copolymerization of one (or more) of the high molecular weight polymers listed above and one (or more) of the selective charge transport polymers listed above.

[0070] Specifically, the materials and ratios of the polymer hole transport material are not limited in the embodiments of this application, and those skilled in the art can select one, two or three of the above materials. Similarly, the materials and ratios of the polymer electron transport material are not limited in the embodiments of this application, and those skilled in the art can select one, two or three of the above materials. In addition, the molecular weight of the selective charge transport polymer or high molecular weight polymer is not specifically limited. As long as the overall performance of the transport layer meets the conductivity, the molecular weight or degree of polymerization can be selected according to the film formation needs.

[0071] In addition, illustratively, a hole transport layer is provided, which is made of polyTPD, P3HT and PMMA. Since polyTPD and P3HT are highly hydrophobic, when the hole transport layer 12 only uses polyTPD and P3HT, when the perovskite film layer 11 is set on the hole transport layer 12, the perovskite film layer 11 is not easy to deposit on its surface. Even if it is deposited, due to the low interfacial bonding force, the efficiency of the perovskite battery 10 will be low and the stability will be poor. The hole transport layer 12 of the embodiment of the present application uses polymer hole transport materials and high molecular polymers. Some of the high molecular polymers (such as PMMA) are more friendly to the wettability of the solution of the perovskite film layer 11, which can improve the bonding force between the hole transport layer 12 and the perovskite film layer 11, avoiding the problem of low efficiency and poor stability of the perovskite battery 10 caused by low interfacial bonding force.

[0072] In one possible implementation of the present application, the high molecular polymer may also contain a coordination group for passivating defects in the perovskite film layer 11; optionally, the coordination group includes one or more of an amino group, a carboxyl group, a hydroxyl group, a benzene ring, and a sulfonic acid, or may be other coordination groups with a passivation effect that are not listed.

[0073] When the hole transport layer 12 uses only one or more of PTAA, polyTPD, P3HT, PEDOT, EDOT:PSS, and PANI, it contacts the perovskite film layer 11 to collect holes. However, the above materials will cause interfacial recombination with the perovskite film layer 11 at the interface between the perovskite film layer 11 and the hole transport layer 12, thereby reducing the efficiency of the perovskite cell 10. The hole transport layer 12 of the embodiment of the present application includes a polymer hole transport material and a high molecular polymer. The high molecular polymer contains a ligand for passivating the defects of the perovskite film layer 11. The ligand has a large proportion at the interface, which can effectively reduce the interfacial recombination, thereby improving the efficiency of the perovskite cell 10. In addition, due to its extremely high molecular weight, the high molecular polymer can completely cover the rough deposition surface, which is beneficial for the perovskite cell 10 to deal with short-circuit channels. Alternatively, the hole transport layer 12 of the embodiment of the present application includes a copolymer formed by a polymer hole transport material and a high molecular polymer, and the copolymer contains a ligand for passivating the defects of the perovskite film layer 11.

[0074] Optionally, the ligands include one or more of amino, carboxyl, hydroxyl, benzene ring, sulfonic acid, or others. Carboxyl, benzene ring, and other ligands can effectively reduce interfacial recombination, thereby improving the efficiency of the perovskite cell 10.

[0075] Specifically, the carboxyl groups in PTAA, the benzene rings in PEDOT, and the high electronegativity of the F group in P3HT can all reduce interfacial recombination. It should be noted that the aforementioned ligands are merely examples and are not intended to limit the scope of ligands. Those skilled in the art may select other ligands based on practical needs.

[0076] In one achievable manner of the embodiment of the present application, the selective charge transport layer may be further doped with an additive for improving carrier mobility, and the additive may include one or both of Li-TFSI and Tbp.

[0077] The selective charge transport layer is also doped with additives, which are used to improve carrier mobility, thereby further reducing the amount of the selective charge transport polymer.

[0078] Another aspect of an embodiment of the present application provides a precursor liquid for preparing a selective charge transport layer, comprising a high molecular weight polymer, a selective charge transport polymer and a solvent; the selective charge transport polymer utilizes electrons or holes to transport charges; and the molecular weight of the high molecular weight polymer is greater than 10,000.

[0079] In one implementation of the embodiment of the present application, the precursor liquid may further include a copolymer of a high molecular polymer and a selective charge transport polymer.

[0080] The present invention also provides another precursor solution for preparing a selective charge transport layer, the precursor solution comprising a copolymer of a high molecular weight polymer and a selective charge transport polymer, and a solvent. The copolymer can transport charges using electrons or holes.

[0081] The precursor liquid is used to prepare the selective charge transport layer. The material of the selective charge transport layer has been described in detail in the selective charge transport layer and will not be repeated here. The specific material of the solvent is not limited in the present embodiment, and chlorobenzene can be used as an example.

[0082] As an practicable approach, the mass ratio of the polymer to the selective charge transport polymer is between 1:4-9:1; preferably, the mass ratio of the polymer to the selective charge transport polymer is between 2:3-3:2. Current experiments have shown that, under the same other experimental conditions, the performance of the device corresponding to this ratio range is better.

[0083] As an practicable manner, the high molecular polymer is one or more combinations of cross-linked polydimethylsiloxane, polymethyl methacrylate, polyvinyl pyrrolidone, poly-4-ethylphenol, polybutylene terephthalate, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polylactic acid, polyformaldehyde, polyamide, polyimide, polyethyleneimine, polydopamine, polyvinylidene fluoride, polyacrylonitrile, or one or more copolymers.

[0084] As an practicable approach, the precursor liquid may include polyTPD, PMMA, and PTAA, and the mass concentration ratio of the three is 3:4:3.

[0085] In another aspect of the embodiment of the present application, Figure 1 and Figure 2 As shown, a perovskite cell 10 is provided, comprising a perovskite film layer and the above-mentioned selective charge transport layer.

[0086] Figure 1 The perovskite cell 10 includes the above-mentioned selective charge transport layer. The specific structure and beneficial effects of the selective charge transport layer have been described in detail in the above-mentioned embodiment and will not be repeated here.

[0087] Another aspect of the embodiments of the present application provides a method for preparing a perovskite battery, which adopts the following selective charge transport layer preparation process, including:

[0088] The precursor liquid of the selective charge transport layer is coated on a substrate to form a selective charge transport layer. The selective charge transport layer includes a high molecular polymer as a matrix material, a selective charge transport polymer doped in the matrix material, and / or a copolymer formed by the high molecular polymer and the selective charge transport polymer.

[0089] When the selective charge transport layer includes a copolymer, it may also include a high molecular polymer that is not copolymerized and a selective charge transport polymer.

[0090] Specifically, the perovskite cell 10 can be disposed on a crystalline silicon bottom electrode or a transparent conductive film. The following describes in detail two methods for preparing the perovskite cell 10 .

[0091] A method for preparing a perovskite battery 10, such as Figure 2 and Figure 3 Shown, including:

[0092] S10: Figure 3 As shown, a crystalline silicon bottom cell 14 is provided, and a hole transport layer 12 is prepared on the crystalline silicon bottom cell 14. The hole transport layer 12 uses a precursor liquid containing a high molecular polymer and a polymer hole transport material provided by the present application;

[0093] The crystalline silicon bottom cell 14 is made of silicon material, and the crystalline silicon bottom cell 14 is provided, cleaned and dried to keep its surface clean and dry. Specific cleaning steps can be set by those skilled in the art according to actual conditions.

[0094] The hole transport layer 12 is prepared on the crystalline silicon base cell 14 using a wet process. Specifically, a polymer and a polymer hole transport material are dissolved in an organic solvent at a specific mass ratio to form a precursor solution. This is then spin-coated onto the crystalline silicon base cell 14 and dried to evaporate the organic solvent. Specifically, the polymer is PMMA and the polymer hole transport material is PTAA, with a mass ratio of 1:1. The precursors are dissolved in 2 mg / ml chlorobenzene. The molecular weight of PMMA is 350,000, and that of PTAA is 7,000.

[0095] S11: If Figure 3 As shown, a perovskite film layer 11 is formed on the hole transport layer 12;

[0096] The preparation of the perovskite film layer 11 specifically includes two steps:

[0097] S111: Forming a metal halide skeleton on the hole transport layer 12. Dissolve lead iodide and cesium iodide in 1 ml of a mixed solution of dimethylformamide and dimethyl sulfoxide (DMSO) at a volume ratio of 9:1. Stir in a 70°C water bath to fully dissolve the mixture to form a spin coating solution. Spin coat the spin coating solution onto the hole transport layer 12. Specifically, spin coat at 2500 rpm for 30 seconds, then anneal on a hot plate at 70°C for 1 minute to complete the preparation of the metal halide skeleton.

[0098] S112: forming a perovskite film layer 11.

[0099] Methionine hydrobromide and methionine hydroiodide were dissolved in isopropanol at a molar ratio of 1.75:1 to form a coating solution, and the coating solution was spin-coated on the metal halide skeleton. Specifically, the coating solution was spin-coated at a speed of 3000 rpm for 30 seconds, and then annealed on a hot plate at 150°C for 30 minutes to complete the preparation of the perovskite film layer 11.

[0100] S12: Figure 3 As shown, an electron transport layer 13 is formed on the perovskite film layer 11;

[0101] The specific method and materials for forming the electron transport layer 13 on the perovskite film layer 11 are not limited in the present embodiment, and those skilled in the art can select them according to actual conditions. For example, the electron transport layer 13 can be formed on the perovskite film layer 11 by vacuum coating. Specifically, the crystalline silicon bottom cell 14 with the perovskite film layer 11 is placed in a vacuum coating device, and a 20 nm thick C layer is evaporated on the perovskite film layer 11. 60 , the evaporation rate is Can be re-instated in C 60 A 7nm thick BCP is evaporated on top. BCP serves as a buffer layer. On the one hand, BCP has a deeper HOMO energy level, which can effectively block holes and help improve the photoelectric conversion efficiency of the device. On the other hand, BCP can be regarded as an electron-rich group because its molecules contain N atoms with lone pairs of electrons, which passivate the halogen vacancy defects on the surface of the perovskite film layer 11, thereby reducing interfacial recombination and improving electron transmission at the interface. The hydrophobic benzene ring in the BCP molecule is also conducive to enhancing the resistance of the interface to the external environment and improving the stability of the device.

[0102] S13: If Figure 3 As shown, an electrode 16 is prepared on the electron transport layer 13 to form a perovskite cell 10 .

[0103] Specifically, a copper electrode 16 with a thickness of 150 nm may be deposited on the buffer layer BCP using a mask method.

[0104] The embodiment of the application can be used in a crystalline silicon perovskite laminated battery, and can also be used in other laminated batteries containing a perovskite film layer, thereby improving the quality of the film layer, reducing the amount of selective charge transport polymer, and having a certain effect of improving photoelectric conversion efficiency.

[0105] In another aspect of the embodiment of the application, a preparation method of a single-junction perovskite battery 10 is provided, as shown in the figure, which comprises the following steps. Figure 4

[0106] S20: as shown in the figure, a glass substrate with a transparent conductive layer 17 is provided, and an electron transport layer 13 is prepared on the transparent conductive layer 17; the electron transport layer 13 adopts a polymer electron transport material and a high molecular polymer material. Figure 5

[0107] The transparent conductive layer 17 is made of transparent conductive glass, and after the transparent conductive glass is provided, the transparent conductive glass is cleaned and dried to keep the surface clean and dry. The specific cleaning steps can be set by those skilled in the art according to the actual situation. For example, the glass can be sequentially cleaned with a glass detergent, deionized water, acetone and anhydrous ethanol, and then dried with dry gas.

[0108] The electron transport layer 13 is spin-coated with a mixed solution of N2200 and PMMT.

[0109] S21: as shown in the figure, a perovskite film layer 11 is formed on the electron transport layer 13; the preparation method of the perovskite film layer 11 is the same as that of the above embodiment, and will not be described here. Figure 5

[0110] S22: as shown in the figure, a hole transport layer 12 is prepared on the perovskite film layer 11; the hole transport layer 12 adopts a polymer hole transport material and a high molecular polymer. Figure 5 When the hole transport layer 12 is prepared on the perovskite film layer 11, a wet method is used. Specifically, the high molecular polymer and the polymer hole transport material are dissolved in an organic solvent in a certain mass ratio to form a precursor solution, which is then spin-coated on the perovskite film layer 11 by a spin coating method and dried to evaporate the organic solvent. Specifically, the high molecular polymer can be PS, and the polymer hole transport material can be polyTPD, and the mass ratio of the two is 1:1, and they are dissolved in 2mg / ml chlorobenzene. The molecular weight of PS is 280000, and the molecular weight of polyTPD is 30000.

[0111] S23: as shown in the figure, an electrode 16 is prepared on the hole transport layer 12 to form a perovskite battery 10.

[0112] Figure 5

[0113] ​​​​​Specifically, a gold electrode 16 with a thickness of 150 nm is deposited on the hole transport layer 12 using a mask method.

[0114] In order to further verify the effect of the selective charge transport layer provided in the embodiment of the present application on the performance of the perovskite cell 10, the present application conducted performance tests on different hole transport layers 12 (with different polymer contents). Specifically, 5 groups of perovskite cells 10 with different hole transport layers 12 were prepared using the same process and the same environment. Each perovskite cell 10 had 5 samples, and the short-circuit current (Jsc), photoelectric conversion efficiency (PCE), open circuit voltage (Voc), and fill factor (FF) of each perovskite cell 10 were tested. Among them, the specific material ratio of the hole transport layer 12 and the test data are shown in Table 1:

[0115] Table 1 Performance comparison of multiple groups of perovskite cells 10

[0116]

[0117] It should be noted that the values ​​of the various test values ​​in Table 1 are the average values ​​of five perovskite batteries 10 under the same conditions. In order to more clearly show the situation of each sample in each group, the data of multiple perovskite batteries 10 are made into box plots based on each group, as shown in Figure 1. Figure 6 As shown, the short-circuit current of multiple perovskite batteries 10 is made into a box diagram in units of each group; Figure 7 As shown, the photoelectric conversion efficiency of multiple perovskite cells 10 is made into a box diagram with each group as a unit; Figure 8 As shown, the open circuit voltage of multiple perovskite cells 10 is a box diagram made of each group; Figure 9 As shown, a box diagram is made of the filling factors of multiple perovskite cells 10 in groups.

[0118] From Table 1 and Figures 6 to 9 It can be seen that when the hole transport layer 12 is added with a polymer, its performance is not significantly affected. As a reference, the short-circuit current (Jsc) of the perovskite cell without the addition of polymer is 19.9 mA·cm 2 The photoelectric conversion efficiency (PCE) was 30.3%, the open circuit voltage (Voc) was 1.88 V, and the fill factor (FF) was 80.8%. After adding polymers in different proportions, the short-circuit current (Jsc) of each group of perovskite cells was 19.7-20 mA·cm 2 , photoelectric conversion efficiency (PCE) 29.3% ~ 31.5%, open circuit voltage (Voc) 1.85 ~ 1.87V, fill factor (FF) 79.4% ~ 83.6%.

[0119] The addition of a high molecular weight polymer to the inner hole transport layer reduces the amount of polymer hole transport material required, thereby simplifying the preparation of the hole transport layer 12 of the perovskite cell 10. This significantly reduces the amount of expensive polymer hole transport material required, while maintaining minimal impact on device performance. The same principle applies to the electron transport layer 13, which will not be discussed further here.

[0120] In addition, based on the comprehensive consideration of various parameters, the third group of perovskite cells 10 have good performance in all directions, with a photoelectric conversion efficiency of 31.5%, an open circuit voltage of 1.87V, a fill factor of 83.6%, and a short-circuit current density of 20mA·cm 2 The fill factor reflects the conductivity of the hole transport layer 12. The fill factor of the third group is higher than that of the first group in the comparative test. Therefore, the conductivity of the hole transport layer 12 of the third group of perovskite cells 10 is higher than that of the hole transport layer 12 without the polymer.

[0121] In addition, in order to further verify the beneficial effects of the embodiments of the present application, wettability tests were performed on the comparative example (sample A) and the embodiment (sample B), and the results are as follows:

[0122] The perovskite wettability of the hole transport layer surface of sample A (containing only polymer hole transport material polyTPD) and sample B (containing polymer hole transport material polyTPD and high molecular weight polymer PTAA) as a reference was tested. The results are as follows Figure 10 and Figure 11 shown.

[0123] Figure 10 In this example, the solution is a perovskite precursor solution, and the contact surface is a hole transport layer formed by PolyTPD. Wettability contact angle measurements were conducted, and the measured contact angles were 49.785° and 49.509°.

[0124] Figure 11 In the solution, the perovskite precursor solution (with Figure 10 The contact surface is a hole transport layer formed by PolyTPD and PMMA. Wettability contact angle measurements were conducted, and the measured contact angles were 11.415° and 11.877°.

[0125] It can be seen that PMMA is added to the hole transport layer of sample B. Due to the presence of carboxyl ligands on the PMMA surface, the wettability of the perovskite solution is significantly improved, which helps to increase the yield of perovskite film formation, enhance the mechanical strength of the interface, and improve long-term stability.

[0126] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A selective charge transport layer, wherein the selective charge transport layer is used for a solar cell, characterized in that: Including a high molecular polymer as a matrix material; a selective charge transport polymer doped in the matrix material, and / or a copolymer formed by the high molecular polymer and the selective charge transport polymer; wherein, The selective charge transport polymer transports electrons or holes; the molecular weight of the high molecular polymer is greater than 10,000.

2. The selective charge transport layer according to claim 1, wherein The mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 1:4 and 9:1; or the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 2:3 and 3:

2.

3. The selective charge transport layer according to claim 1, wherein The high molecular polymer is one or more of cross-linked polydimethylsiloxane, polymethyl methacrylate, polyvinyl pyrrolidone, poly-4-ethylphenol, polyethylene terephthalate, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polylactic acid, polyformaldehyde, polyamide, polyimide, polyethyleneimine, polydopamine, polyvinylidene fluoride, polyacrylonitrile, or a combination of one or more thereof, or a copolymer of one or more thereof.

4. The selective charge transport layer according to any one of claims 1 to 3, characterized in that The selective charge transport polymer is a polymer hole transport material for a hole transport layer, or a polymer electron transport material for an electron transport layer.

5. The selective charge transport layer according to claim 4, characterized in that The polymer hole transport material is a combination of one or more of PTAA, polyTPD, P3HT, PEDOT, PEDOT:PSS, PANI, or a derivative of one or more thereof; The polymer electron transport material includes a combination of one or more of N2200, N2300, N-CS2DPP-OD-TEG, P-BNBP-T, and P-IFDMT4, or a derivative of one or more of the above.

6. The selective charge transport layer according to claim 1, wherein The high molecular polymer contains a coordination group for passivating defects in the perovskite film; the coordination group includes one or more of an amino group, a carboxyl group, a hydroxyl group, a benzene ring, and a sulfonic acid.

7. The selective charge transport layer according to claim 1, wherein It is also doped with additives for improving carrier mobility, including Li-TFSI and tBP.

8. A precursor liquid for preparing a selective charge transport layer, characterized in that: include: A high molecular weight polymer, a selective charge transport polymer, and / or a copolymer formed by the high molecular weight polymer and the selective charge transport polymer, and a solvent, wherein: The selective charge transport polymer utilizes electrons or holes to transport charges; the molecular weight of the high molecular polymer is greater than 10,000.

9. The precursor liquid according to claim 8, characterized in that The mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 1:4 and 9:1; or the mass ratio of the high molecular weight polymer to the selective charge transport polymer is between 2:3 and 3:

2.

10. The precursor liquid according to claim 8, characterized in that The high molecular polymer is a combination of one or more of cross-linked polydimethylsiloxane, polymethyl methacrylate, polyvinyl pyrrolidone, poly-4-ethylphenol, polyethylene terephthalate, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polyvinyl alcohol, polylactic acid, polycarbonate, polyacrylic acid, plastic starch material, polysulfone, polyurethane, polyformaldehyde, polyamide, polyimide, polyamideimide, polyethyleneimine, polydopamine, polyvinylidene fluoride, polyacrylonitrile, polyetheretherketone, epoxy resin and ABS resin, or a copolymer of one or more of them.

11. The precursor liquid according to any one of claims 8 to 10, characterized in that: The precursor liquid includes polyTPD, PMMA and PTAA, and the mass concentration ratio of the three is 3:4:

3.

12. A perovskite battery, characterized in that: The method comprises a perovskite film layer and a selective charge transport layer according to any one of claims 1 to 7.

13. A method for preparing a perovskite battery, comprising a process for preparing a selective charge transport layer, characterized in that: The preparation process of the selective charge transport layer comprises: A precursor liquid of the selective charge transport layer according to any one of claims 8 to 10 is coated on a substrate to form a selective charge transport layer, wherein the selective charge transport layer includes a high molecular weight polymer as a matrix material, a selective charge transport polymer doped in the matrix material; and / or a copolymer formed by the high molecular weight polymer and the selective charge transport polymer.

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