Perovskite solar cell and preparation method thereof

Abstract

The invention discloses a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer and a first electrode which are sequentially laminated, the hole transport layer comprises at least one of a first transport layer and a second transport layer which are laminated, the material of the second transport layer comprises cation-doped metal oxide, and the material of the electron transport layer comprises cation-doped metal oxide. The second transmission layer is located between the first transmission layer and the perovskite absorption layer. Wherein the second transmission layer in the hole transmission layer adopts the cation-doped metal oxide, so that the perovskite crystallinity can be effectively improved, the hole concentration of the hole transmission layer is improved, and the loss of interface charge transmission is reduced. And the prepared cation-doped metal oxide film has excellent texture conformality and thickness uniformity, large-area device preparation and large-scale mass production can be realized, and large-scale commercial application of the perovskite / crystalline silicon laminated solar cell is facilitated.

Description

Technical Field

[0001] The present application relates to the field of solar cells, and more specifically, to a perovskite solar cell and a method for preparing the same. Background Art

[0002] NiO x Hole transport layers have a series of advantages such as high hole mobility, relative stability, easy preparation, low cost and matching with the perovskite valence band, so they are widely used in perovskite solar cells and perovskite / crystalline silicon tandem solar cells. x The poor interface contact between the hole transport layer and the perovskite film is not conducive to the growth of high-quality perovskite films and may produce certain interface defects. x There is a lot of Ni on the surface 3+ , resulting in increased non-radiative recombination at the interface and decomposition of the perovskite film, and a significant decrease in device performance.

[0003] In order to passivate NiO x The industry usually uses NiO x / SAMs is a typical double-layer hole transport layer structure, that is, in NiO x A thin layer of small molecule self-assembled layer is prepared on the surface, such as 2PACz, 4PACz, MeO-2PACz, Me-4PACz, etc. However, the intrinsic conductivity of these small molecule self-assembled layers is not ideal, and the device efficiency is extremely sensitive to the film thickness of the SAM molecules. The uncontrolled self-assembly state of such molecules on the substrate and the uneven distribution on the molecular scale will cause interfacial charge transfer losses, a large number of buried interface micropores and unsatisfactory perovskite crystallization, resulting in a large number of buried interface defects causing serious interface recombination. More importantly, the current method of preparing self-assembled layers mainly uses spin coating, which cannot prepare large-area devices and achieve large-scale mass production. Summary of the invention

[0004] The present application provides a perovskite solar cell and a preparation method thereof, so as to solve the problems in the related art that the state of small molecule self-assembled layers (SAMs) is uncontrolled, the uneven distribution of molecular scales causes interface recombination, and large-scale mass production cannot be achieved.

[0005] According to one aspect of the present application, a perovskite solar cell is provided, comprising: a substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer and a first electrode stacked in sequence, wherein the hole transport layer comprises at least one first transport layer and a second transport layer stacked in layers, the material of the second transport layer comprises a cation-doped metal oxide, and the second transport layer is located between the first transport layer and the perovskite absorption layer.

[0006] Optionally, the material of the metal oxide of the second transmission layer includes tin oxide.

[0007] Optionally, the valence of the cation is less than or equal to 3.

[0008] Optionally, the first transmission layer and the second transmission layer comprise different metal oxides.

[0009] Optionally, the first transmission layer and the second transmission layer have different work functions.

[0010] Optionally, the second transmission layer has a thickness of 1 nm to 30 nm.

[0011] Optionally, the substrate includes any one of FTO conductive glass, ITO conductive glass, AZO conductive glass, a conductive flexible substrate and a solar bottom cell.

[0012] According to another aspect of the present application, a method for preparing a perovskite solar cell is provided, comprising: providing a substrate; sequentially stacking a hole transport layer, a perovskite light absorbing layer, an electron transport layer, a buffer layer and an electrode on the surface of the substrate, wherein the hole transport layer comprises at least one first transport layer and a second transport layer stacked, the material of the second transport layer comprises a cation-doped metal oxide, and the second transport layer is located between the first transport layer and the perovskite absorption layer.

[0013] Optionally, the step of forming the second transmission layer includes: depositing a first metal oxide on the first transmission layer using a deposition process to form the second transmission layer, wherein the first metal oxide includes the cation-doped metal oxide.

[0014] Optionally, the step of forming the second transport layer includes: using a deposition process to deposit a second metal oxide and a doping material on the first transport layer to form the second transport layer, wherein the doping material contains doped cations.

[0015] Through the technical solution of the present application, a perovskite solar cell is provided, which includes a substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer and a first electrode, wherein the second transport layer in the hole transport layer adopts a cation-doped metal oxide, the crystal structure of the metal oxide is stable and has a high density, and the small molecule self-assembled layer (SAMs) is replaced by a metal oxide, which can effectively avoid the interfacial charge transfer loss and the poor crystallization of the perovskite caused by the uncontrolled self-assembly state and uneven molecular scale of the small molecule self-assembled layer (SAMs), thereby improving the crystallinity of the perovskite, and the metal oxide is doped with cations, which improves the hole concentration of the second transport layer and reduces the loss of interfacial charge transfer. The cation-doped metal oxide can be prepared by a relatively mature deposition process, and the prepared film layer has excellent velvet conformality and thickness uniformity, which can realize the preparation of large-area devices and large-scale mass production, which is conducive to the large-scale commercial application of perovskite / crystalline silicon stacked solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0017] Figure 1 It is a schematic diagram of the cross-sectional structure of a perovskite solar cell according to an embodiment of the present application;

[0018] Figure 2 is a schematic diagram of the cross-sectional structure of another perovskite solar cell according to an embodiment of the present application;

[0019] Figure 3 is a schematic diagram of the energy band structure of a hole transport layer of a perovskite solar cell according to an embodiment of the present application;

[0020] Figure 4 is a schematic diagram of the energy band structure of a hole transport layer of another perovskite solar cell according to an embodiment of the present application;

[0021] Figure 5 is a schematic diagram of the cross-sectional structure of another perovskite solar cell according to an embodiment of the present application;

[0022] Figure 6 is a schematic cross-sectional structure diagram of another perovskite solar cell according to an embodiment of the present application;

[0023] Figure 7 is a schematic cross-sectional structure diagram of another perovskite solar cell according to an embodiment of the present application;

[0024] Figure 8is a flow chart of a method for preparing a perovskite solar cell according to an embodiment of the present application;

[0025] Fig. 9 It is a schematic diagram of the cross-sectional structure of a solar bottom cell according to an embodiment of the present application.

[0026] The above drawings include the following reference numerals:

[0027] 10. Substrate; 101. Bottom TCO film layer; 102. First hydrogenated amorphous silicon layer; 1031. First intrinsic hydrogenated amorphous silicon layer; 1032. Second intrinsic hydrogenated amorphous silicon layer; 104. Single crystal silicon layer; 105. Second hydrogenated amorphous silicon layer; 106. Second electrode; 20. Hole transport layer; 21. First transport layer; 211. First sub-transport layer; 212. Second sub-transport layer; 22. Second transport layer; 30. Perovskite absorption layer; 40. Electron transport layer; 50. First electrode; 70. Buffer layer; 80. Conductive layer; 90. Tunneling layer. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in 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. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] As described in the background technology, the current hole transport layer in the industry uses NiO x / SAMs double-layer structure, the self-assembly state of the small molecule self-assembled layer (SAMs) on the substrate is uncontrolled, the uneven distribution on the molecular scale will cause interface charge transfer loss, a large number of buried interface micropores and perovskite crystallization are not ideal, resulting in a large number of buried interface defects causing serious interface recombination, and the preparation method of the self-assembled layer is mainly a spin coating method, which cannot prepare large-area devices and achieve large-scale mass production. In order to solve the above technical problems, the present application provides a perovskite solar cell and a preparation method thereof.

[0032] According to an embodiment of the present application, a perovskite solar cell is provided, such as Figure 1 As shown, it includes: a substrate 10, a hole transport layer 20, a perovskite absorption layer 30, an electron transport layer 40 and a first electrode 50 which are stacked in sequence, wherein the hole transport layer 20 includes at least one first transport layer 21 and a second transport layer 22 which are stacked, and the material of the second transport layer 22 includes a cation-doped metal oxide, and the second transport layer 22 is located between the first transport layer 21 and the perovskite absorption layer 30. Among them, the second transport layer 22 in the hole transport layer 20 uses a cation-doped metal oxide, and the crystal structure of the metal oxide is stable and has high compactness. Replacing the small molecule self-assembled layer (SAMs) with a metal oxide can effectively avoid the problems of interfacial charge transmission loss and poor perovskite crystallization caused by the uncontrolled self-assembly state and uneven molecular scale of the small molecule self-assembled layer (SAMs), thereby improving the perovskite crystallinity, and the metal oxide is doped with cations, which improves the hole concentration of the second transport layer and reduces the loss of interfacial charge transmission. Cation-doped metal oxides can be prepared using a relatively mature deposition process. The prepared film layer has excellent velvet conformality and thickness uniformity, which can realize the preparation of large-area devices and large-scale mass production, which is conducive to the large-scale commercial application of perovskite / crystalline silicon stacked solar cells.

[0033] In an optional embodiment, the metal oxide material of the second transmission layer includes tin oxide.

[0034] Specifically, tin oxide (SnO2) has a lower resistivity, and the conduction band energy level is around -4.5eV, while the perovskite material reversal band is at 3.4 to 3.9eV. Therefore, SnO2 can form an energy level match with the perovskite material. The electron mobility of tin oxide is high (240cm 2 / (V·s)), which is beneficial to shorten the transmission time of electrons in the perovskite film and inhibit the recombination of electron-hole pairs. Thus, SnO2 can passivate the surface defects of the first transmission layer, inhibit the non-radiative recombination at the interface, and improve the stability of the device. In addition, SnO2 has excellent chemical stability, UV resistance and anti-reflection, and low photocatalytic activity. These excellent properties are beneficial to improving the stability of the device and extending its service life, and it is widely used in perovskite solar cells.

[0035] In an alternative embodiment, the valence state of the cation in the cation-doped metal oxide is less than or equal to 3.

[0036] Specifically, the interstitial Sn in the SnO2 crystal 4+ When cations with a valence less than or equal to 3 are doped into SnO2 crystals, they replace Sn 4+ , forming P-type doping, which can provide more holes in SnO2, thereby significantly enhancing the hole concentration of SnO2.

[0037] Among them, trivalent cations include but are not limited to antimony ions (Sb 3+ ), bismuth ion (Bi 3+ ), iron ions (Fe 3+ ), aluminum ions (Al 3+ ), chromium ion (Cr 3+ ), cobalt ions (Co 3+ ), Scandium ions (Sc 3+ ), thallium ion (Tl 3+ ), yttrium ion (Y 3+ ), thulium ion (Tm 3+ ), hafnium ions (Hf 3+ ), indium ions (In 3+ ), divalent cations include but are not limited to beryllium ions (Be 2+ ), copper ions (Cu 2 + ), nickel ions (Ni 2+ ), magnesium ion (Mg 2+ ), calcium ions (Ca 2+ ), strontium ion (Sr 2+ ), barium ions (Ba 2+ ), zinc ion (Zn 2+ ), cadmium ions (Cd 2+ ), monovalent cations include but are not limited to sodium ions (Na + ), lithium ion (Li + ), silver ions (Ag + ), rubidium ions (Rb + ), cesium ion (Cs + ), ammonium ion (NH4+ ), ammonium silver ion (AgNH 4+ ), sodium ammonium ions (NaNH 4+ ), the cations doped into the metal oxide may include one or more of the above cations, and those skilled in the art may select them according to product requirements, and this application does not make any specific limitations.

[0038] In an optional embodiment, the first transmission layer 21 and the second transmission layer 22 include different metal oxides.

[0039] Specifically, the first transport layer 21 and the second transport layer 22 use different metal oxides, and the different metal oxide films interact with each other to achieve complementary advantages of different metal oxides, which can improve the interface composite defects of a single metal oxide film as a hole transport layer, thereby effectively eliminating the vacancy defects of cations and anions in the perovskite absorption layer, improving carrier mobility, reducing non-radiative recombination, and improving the photoelectric conversion efficiency of the device. For example, NiO x NiO is widely used in the hole transport layer of perovskite solar cells due to its advantages such as high hole mobility. x Problems such as energy level mismatch with the perovskite absorption layer, poor interface contact, and many defects are not conducive to the growth of high-quality perovskite films, and may produce certain interface defects, thereby affecting battery performance. x There is a lot of Ni on the surface 3+ , resulting in increased non-radiative recombination at the interface and decomposition of the perovskite film, which significantly reduces device performance. x Another SnO2 film is formed on the film layer, and the SnO2 film passivates the NiO x Surface defects, avoiding Ni 3+ The influence on the perovskite absorption layer, and the energy level matching and good interface contact between the SnO2 film and the perovskite absorption layer are conducive to the formation of the perovskite absorption layer. x The SnO2 film layer and the SnO2 film layer work synergistically to improve carrier mobility, reduce interface recombination anomalies, and improve the photoelectric conversion efficiency of the device.

[0040] Furthermore, the first transmission layer includes a metal oxide layer or multiple metal oxide layers, which is not specifically limited in this application. Specifically, Figure 2 As shown, the first transmission layer 21 is a multi-layer film layer, including a first sub-transmission layer 211 and a second sub-transmission layer 212. Different metal oxides are also included between the first sub-transmission layer 211 and the second sub-transmission layer 212. The metal oxides of each layer work together to improve the performance of the first transmission layer 21. In addition, Figure 2 The positional relationship of other structures shown in Figure 1The positional relationship of the structure is the same as that of the structure in FIG. 1 , and will not be repeated here. The material of the first transmission layer 21 includes but is not limited to NiO x , CuO x 、MoO x ,Wo x One or more of .

[0041] In some optional embodiments, the first transport layer and the second transport layer have different work functions.

[0042] Specifically, sunlight irradiates into the perovskite absorption layer, and the perovskite absorption layer is stimulated to generate electron-hole pairs, which diffuse to the interface and separate to form free electrons and holes, and then are transferred to the corresponding electrodes through the electron / hole transport layer for collection. Among them, the holes flow through the hole transport layer and are transferred to the electrode. The work functions of the first transport layer and the second transport layer in the hole transport layer are different, forming an energy level gradient, reducing the energy level barrier, promoting energy level matching, improving the hole transfer efficiency, and improving the photoelectric conversion efficiency of the device. Furthermore, in the case where the first transport layer is a multi-layer film layer, each film layer also has a different work function.

[0043] For example, Figure 3 As shown, the first transport layer 21 is a single-layer structure, and the work function of the first transport layer 21 is smaller than the work function of the second transport layer 22. When the light source irradiates the solar cell, the perovskite absorption layer 30 is excited to generate electron and hole pairs, and the electrons jump to the electron transport layer 40, and the holes jump to the hole transport layer 20. Since the first transport layer 21 and the second transport layer 22 in the hole transport layer 20 form an energy level gradient, the holes jump from the second transport layer 22 to the first transport layer 21, which reduces the energy level barrier of the hole transport layer, promotes the transmission of holes, and increases the photoelectric conversion efficiency of the device.

[0044] For example, Figure 4 As shown, the first transmission layer 21 is a multi-layer structure, and the first transmission layer 21 includes a first sub-transmission layer 211 and a second sub-transmission layer 212, wherein the work function of the first sub-transmission layer is smaller than the work function of the second sub-transmission layer, and the work function of the second sub-transmission layer is smaller than the work function of the second transmission layer 22, and an energy level barrier is formed in the hole transmission layer. When the light source irradiates the solar cell, the perovskite absorption layer 30 is excited to generate electron and hole pairs, and the electrons transition to the electron transmission layer 40, and the holes transition to the hole transmission layer 20. Since the first sub-transmission layer 211, the second sub-transmission layer 212 and the second transmission layer 22 in the hole transmission layer 20 form an energy level gradient, the holes transition from the second transmission layer 22 to the second sub-transmission layer 212, and then transition from the second sub-transmission layer 212 to the first sub-transmission layer 211, which slows down the energy level barrier of the hole transmission layer, promotes the transmission of holes, and increases the photoelectric conversion efficiency of the device.

[0045] In some optional embodiments, the thickness of the second transmission layer 22 is 1 nm to 30 nm. For example, the specific thickness of the second transmission layer 22 may be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm or 30 nm.

[0046] Specifically, the thickness of the first transmission layer 21 is 5 nm to 100 nm, wherein the specific thickness of the first transmission layer 21 can be 5 nm, 20 nm, 40 nm, 50 nm, 75 nm or 100 nm. The first transmission layer 21 can play the role of mainly transmitting holes and increase the photoelectric conversion efficiency. While transmitting holes, the second transmission layer can improve the surface defects of the first transmission layer and improve the energy level matching between the first transmission layer and the perovskite absorption layer.

[0047] In some optional embodiments, the substrate includes any one of FTO conductive glass, ITO conductive glass, AZO conductive glass, a conductive flexible substrate and a solar bottom cell.

[0048] Specifically, the perovskite electrode in the present application includes a single-section perovskite solar cell and also includes a perovskite stacked solar cell.

[0049] For example, the perovskite solar cell in the present application is as follows Figure 1 The perovskite single-cell solar cell shown. Wherein, the substrate 10 may include a conductive glass substrate, which can be used as the second electrode of the perovskite solar cell. Wherein, the conductive glass substrate may include FTO conductive glass, ITO conductive glass, AZO conductive glass and a conductive flexible substrate. A hole transport layer 20, a perovskite absorption layer 30, an electron transport layer 40 and a first electrode 50 are sequentially stacked on the substrate 10, wherein the hole transport layer 20 includes at least one first transport layer 21 and a second transport layer 22 stacked, and the material of the second transport layer 22 includes a cation-doped metal oxide, forming a perovskite single-cell solar cell structure. The preparation process of the single-cell solar cell is mature, large-area preparation can be achieved, and it has high stability.

[0050] Among them, Figure 5As shown, on the basis of a perovskite single-cell solar cell, the perovskite single-cell solar cell includes a substrate 10, a hole transport layer 20, a perovskite absorption layer 30 and an electron transport layer 40 stacked in sequence, the hole transport layer 20 includes at least one first transport layer 21 and a second transport layer 22 stacked, and a buffer layer 70 and a conductive layer 80 are formed between the electron transport layer 40 and the first electrode 50, wherein the buffer layer 70 is used to reduce the mutual influence between the electron transport layer 40 and the first electrode 50, reduce the defect density of the battery, and improve the overall efficiency and stability of the battery. The conductive layer 80 has good conductivity and transparency, can effectively transfer electrons and allow light to penetrate into the perovskite layer, and at the same time protects the perovskite layer from being eroded or damaged by the external environment. In addition, the material of the buffer layer 70 may include but is not limited to SnO2, TiO2, C 60 , a combination of one or more materials of PCBB-2CN-2C8; the material of the conductive layer 80 includes but is not limited to one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO) and zinc-doped tin oxide (ZTO) to improve the photoelectric conversion efficiency of solar cells.

[0051] In another example, the perovskite solar cell in the present application is as follows Figure 6The perovskite tandem solar cell structure shown. The substrate 10 in the perovskite solar cell may include a solar bottom cell, which may include a crystalline silicon bottom cell, and its structure includes: a bottom TCO film layer 101, and a first hydrogenated amorphous silicon layer 102, a first intrinsic hydrogenated amorphous silicon layer 1031, a single crystal silicon layer 104, a second intrinsic hydrogenated amorphous silicon layer 1032, and a second hydrogenated amorphous silicon layer 105 are sequentially stacked and arranged on the first surface of the bottom TCO film layer 101 along a direction perpendicular to the first surface, the surface of the second hydrogenated amorphous silicon layer 105 away from the bottom TCO film layer 101 is the bottom cell, that is, the front side of the substrate 10, and the solar bottom cell may also include a second electrode 106 formed on the back side of the bottom TCO film layer 101. A tunneling layer 90 is formed on the surface of the second hydrogenated amorphous silicon layer 105 in the solar bottom cell, wherein the tunneling layer 90 is used to form an electrical connection between the perovskite cell and the solar bottom cell. A hole transport layer 20, a perovskite absorption layer 30, an electron transport layer 40, and a first electrode 50 are sequentially stacked on the tunneling layer 90, wherein the hole transport layer 20 includes at least one first transport layer 21 and a second transport layer 22, and the material of the second transport layer 22 includes a cation-doped metal oxide, forming a perovskite stacked solar cell structure. The perovskite stacked solar cell structure of this structure combines the advantages of perovskite solar cells and traditional silicon crystal solar cells, broadens the absorption spectrum of solar cells, and obtains higher photoelectric conversion efficiency.

[0052] Among them, Figure 7 As shown, based on the structure of the perovskite stacked solar cell, a buffer layer 70 and a conductive layer 80 are formed between the electron transport layer 40 and the first electrode 50, wherein the buffer layer 70 is used to prevent the mutual influence between the electron transport layer 40 and the first electrode 50, reduce the defect density of the battery, and improve the overall efficiency and stability of the battery; the conductive layer 80 has good conductivity and transparency, can effectively transfer electrons and allow light to penetrate the perovskite layer, and at the same time protect the perovskite layer to prevent it from being eroded or damaged by the external environment. The material of the buffer layer 70 may include but is not limited to SnO2, TiO2, C 60 , a combination of one or more materials of PCBB-2CN-2C8; the material of the conductive layer 80 includes but is not limited to one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO) and zinc-doped tin oxide (ZTO) to improve the photoelectric conversion efficiency of solar cells.

[0053] According to another aspect of the present application, a method for preparing a perovskite solar cell is also provided. Figure 8 As shown, including:

[0054] Step S101: providing a substrate;

[0055] Step S102: stacking a hole transport layer, a perovskite light absorbing layer, an electron transport layer, a buffer layer and an electrode in sequence on the surface of the substrate, wherein the hole transport layer includes at least one first transport layer and a second transport layer stacked, the material of the second transport layer includes a cation-doped metal oxide, and the second transport layer is located between the first transport layer and the perovskite light absorbing layer.

[0056] By adopting the above-mentioned preparation method of the embodiment of the present application, a metal oxide with a stable crystal structure and high density is used to replace the small molecule self-assembled layer (SAMs), which can effectively avoid the interfacial charge transfer loss and poor perovskite crystallization caused by the uncontrolled self-assembly state and uneven molecular scale of the small molecule self-assembled layer (SAMs), and improve the perovskite crystallinity. In addition, cations are doped in the metal oxide, which increases the hole concentration of the second transport layer and reduces the loss of interfacial charge transfer. The cation-doped metal oxide can be prepared by a relatively mature deposition process, and the prepared film layer has excellent velvet conformality and thickness uniformity, which can realize the preparation of large-area devices and large-scale mass production, which is conducive to the large-scale commercial application of perovskite solar cells.

[0057] The following will describe in more detail the exemplary embodiments of the method for preparing the perovskite solar cell provided by the present application in conjunction with the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0058] First, step S101 is performed: providing a substrate.

[0059] Specifically, the substrate may include a glass substrate, specifically, the glass substrate may include FTO conductive glass, ITO conductive glass, AZO conductive glass, or a conductive flexible substrate; in addition, the substrate may also include a solar bottom cell, specifically, the solar bottom cell may include a silicon bottom cell, wherein the silicon bottom cell structure is as follows: Fig. 9As shown, the bottom TCO film layer 101 and the first hydrogenated amorphous silicon layer 102, the first intrinsic hydrogenated amorphous silicon layer 1031, the single crystal silicon layer 104, the second intrinsic hydrogenated amorphous silicon layer 1032 and the second hydrogenated amorphous silicon layer 105 are sequentially formed and stacked on the first surface of the bottom TCO film layer 101 along the vertical direction on the first surface. The surface of the second hydrogenated amorphous silicon layer 105 away from the bottom TCO film layer 101 is the bottom cell, that is, the front side of the substrate 10. The solar bottom cell may also include a second electrode 106 formed on the back side of the bottom TCO film layer 101. A tunneling layer 90 is formed on the surface of the second hydrogenated amorphous silicon layer 105 in the solar bottom cell, wherein the tunneling layer 90 is used to form an electrical connection between the perovskite cell and the solar bottom cell.

[0060] Then, on the provided substrate, step S102 is performed: a hole transport layer, a perovskite active layer, an electron transport layer and a first electrode are sequentially formed on the provided substrate.

[0061] Specifically, the above S102 may include the following steps:

[0062] First, step S1021 is performed: a hole transport layer is formed on the substrate by a deposition process, wherein the hole transport layer includes at least one first transport layer and a second transport layer arranged in a stacked manner, the material of the second transport layer includes a cation-doped metal oxide, and the second transport layer is located between the first transport layer and the perovskite absorption layer. In addition, the first transport layer can be a single-layer film layer or a multi-layer film layer. The material of the first transport layer includes but is not limited to NiO x , CuO x 、MoO x ,Wo x One or more of .

[0063] In some specific embodiments, in the deposition process for forming the first transport layer, a gas including argon and oxygen is used as a raw material gas, the flow rate of argon is 30 sccm to 400 sccm, the flow rate of oxygen is 0.1 sccm to 20 sccm, the reaction pressure is 0.1 Pa to 1 Pa, and the reaction temperature is 25° C. to 230° C., wherein the vacuum degree at the start of the deposition process is less than 1×10 -4 Pa, the DC power applied to the target during the deposition process is 10W~200W.

[0064] In some specific embodiments, in the deposition process for forming the second transport layer, a gas including argon and oxygen is used as a raw material gas, the flow rate of argon is 30 sccm to 200 sccm, the flow rate of oxygen is 0.1 sccm to 10 sccm, the reaction pressure is 0.1 Pa to 1 Pa, and the reaction temperature is 25° C. to 230° C., wherein the vacuum degree at the start of the deposition process is less than 1×10-4 Pa, the DC power applied to the target during the deposition process is 50W~300W.

[0065] Exemplarily, the step of forming the second transmission layer includes depositing a first metal oxide on the first transmission layer using a deposition process to form the second transmission layer, wherein the first metal oxide includes a cation-doped metal oxide.

[0066] Exemplarily, the step of forming the second transport layer may further include using a deposition process to deposit a second metal oxide and a doping material on the first transport layer to form the second transport layer, wherein the doping material contains doped cations, and the doping material includes but is not limited to metal oxides or metals.

[0067] Then, step S1022 is performed: forming a perovskite active layer on the hole transport layer, wherein the process of forming the perovskite active layer includes but is not limited to deposition, spraying, spin coating, thermal evaporation or screen printing followed by low temperature (eg <150° C.) heat treatment.

[0068] Then, step S1023 is performed: an electron transport layer is formed on the perovskite active layer by a deposition process, wherein the material of the electron transport layer may include but is not limited to SnO2, ZnO, TiO2, PCBM, C 60 , a combination of one or more materials.

[0069] Then, step S1024 is performed: a first electrode is formed on the perovskite active layer. The process of forming the first electrode includes but is not limited to screen printing, thermal evaporation and magnetron sputtering processes. The first electrode material includes but is not limited to a combination of one or more materials of Au, Ag, Cu and Al.

[0070] In some optional embodiments, a buffer layer and a conductive layer are formed between the perovskite active layer and the first electrode, wherein the buffer layer is used to interact between the electron transport layer and the first electrode, reduce the defect density of the battery, and improve the overall efficiency and stability of the battery. The conductive layer has good conductivity and transparency, can effectively transfer electrons and allow light to penetrate the perovskite layer, and at the same time protect the perovskite layer from being eroded or damaged by the external environment. Among them, the material of the conductive layer includes but is not limited to one or more of indium zinc oxide (IZO), indium tin oxide (ITO), indium hydroxide-doped (In2O3:H), aluminum-doped zinc oxide (AZO), zirconium-doped indium oxide (IZrO) and zinc-doped tin oxide (ZTO) to improve the photoelectric conversion efficiency of solar cells.

[0071] Specifically, the above-mentioned deposition processes include but are not limited to physical vapor deposition (PVD), chemical vapor deposition (CVD) and atomic layer deposition (ALD), among which physical vapor deposition (PVD) includes but is not limited to magnetron sputtering process, reactive sputtering process, DC sputtering process, AC sputtering process, vacuum coating process, arc evaporation process, chemical vapor deposition (CVD) includes but is not limited to plasma enhanced chemical vapor deposition (PECVD), metal organic compound chemical vapor deposition (MOCVD), laser induced chemical vapor deposition (LCVD), and technical personnel in this field can make reasonable selections according to actual needs, and no specific limitation is made without application.

[0072] The crystalline silicon stacked solar cell and the preparation method thereof provided by the present application will be further described below in combination with embodiments and comparative examples.

[0073] Example 1

[0074] The method for preparing a perovskite crystalline silicon tandem solar cell including a double-layer hole transport layer provided in this embodiment comprises the following steps:

[0075] A crystalline silicon bottom cell is provided; a boron diffusion layer is formed on an N-type silicon wafer by a laser grooving and local diffusion process, and borosilicate glass is removed and the silicon wafer is cleaned to form a single crystal silicon layer; a first intrinsic hydrogenated amorphous silicon layer and a second intrinsic hydrogenated amorphous silicon layer are respectively formed on two opposite surfaces of the single crystal silicon layer by a plasma vapor deposition process, a P-type first hydrogenated amorphous silicon layer is formed on the surface of the first intrinsic hydrogenated amorphous silicon layer, and an N-type second hydrogenated amorphous silicon layer is formed on the surface of the second intrinsic hydrogenated amorphous silicon layer by a plasma vapor deposition process, a bottom TCO film layer is formed on the surface of the first hydrogenated amorphous silicon layer away from the single crystal silicon layer by a magnetron sputtering process, a first electrode is formed on the surface of the bottom TCO film layer away from the single crystal silicon layer by screen printing and high temperature sintering, the material of the first electrode is Ag, and an indium tin oxide (ITO) film layer is formed on the surface of the second hydrogenated amorphous silicon layer to form a tunneling layer, so as to prepare a crystalline silicon bottom cell;

[0076] Formation of NiO on crystalline silicon bottom cell using magnetron sputtering process x The first transport layer of the hole transport layer is formed by placing the crystalline silicon bottom cell into the chamber of the magnetron sputtering coating apparatus, and the reaction chamber of the magnetron sputtering apparatus is evacuated to a vacuum degree of less than 1×10 -4 After the reaction chamber is heated to 300 ℃, high-purity argon gas is introduced into the reaction chamber at a flow rate of 75 sccm. The pressure in the chamber is controlled to be about 0.45 Pa, and the temperature in the reaction chamber is 200 °C. Then, high-purity oxygen gas is introduced into the reaction chamber at a flow rate of 0.4 sccm. After the chamber pressure is stable, a DC power supply is connected to set the NiO xThe DC power of the target is 60W. After 1min of pre-sputtering, the substrate baffle is opened to start film deposition, forming a 20nm thick NiO layer on the tunneling layer. x hole transport layer;

[0077] The magnetron sputtering process was used to deposit NiO x The sputtering layer includes Sb 3+ The target material of doped SnO2 forms Sb 3+ The SnO2 doped film layer (SnO2:Sb film layer) with a thickness of 5 nm is used as the second transport layer of the hole transport layer. Specifically, the reaction chamber of the magnetron sputtering instrument is evacuated to a vacuum degree of less than 1×10 -4 Pa, high-purity argon gas is introduced into the reaction chamber, the flow rate of high-purity argon gas is 60sccm, the pressure in the chamber is controlled to be about 0.36Pa, the temperature in the reaction chamber is 25℃, and then high-purity oxygen gas is introduced into the reaction chamber, the flow rate of high-purity oxygen gas is 1.5sccm, and after the chamber pressure is stable, the DC power supply is connected. After the chamber pressure is stable, the Sb 3+ The DC power of the doped SnO2 target was 30 W. After 1 min of pre-sputtering, the substrate baffle was opened to start film deposition, and a SnO2:Sb hole transport layer with a thickness of 5 nm was prepared on the first transport layer.

[0078] A perovskite active layer is formed on the second transport layer using a deposition process with a thickness of 300 nm;

[0079] The C is formed on the perovskite active layer by a deposition process. 60 A layer with a thickness of 30 nm to form an electron transport layer;

[0080] A tin oxide layer with a thickness of 50 nm is formed on the electron transport layer by a deposition process to form a buffer layer;

[0081] An IZO layer having a thickness of 40 nm is formed on the buffer layer by a deposition process to form a conductive layer;

[0082] A first electrode is formed on the conductive layer by a deposition process, with a thickness of 40 nm and made of Ag.

[0083] Example 2

[0084] The difference between this embodiment and embodiment 1 is that in this embodiment, when preparing the second transport layer of the hole transport layer, Sb2O3 target and SnO2 target are provided to form a hole transport layer on the NiO x A SnO2:Sb hole transport layer was prepared on the surface.

[0085] Example 3

[0086] The difference between this embodiment and embodiment 1 is that the substrate of this embodiment is ITO conductive glass.

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that the preparation steps of the second transport layer in the hole transport layer include:

[0089] The NiO x A MeO-2PACz self-assembled monolayer was prepared on the NiO substrate to serve as the second transport layer of the hole transport layer. Specifically, a MeO-2PACz solution was uniformly coated on the NiO substrate. x The substrate was spin coated at a speed of 3000 rpm / min for 30 s and annealed at 100°C for 10 min in air, and a perovskite absorber layer was formed on the MeO-2PACz self-assembled monolayer.

[0090] Comparative Example 2

[0091] The difference between this comparative example and comparative example 1 is that the substrate of this example is ITO conductive glass.

[0092] The spectrum distribution is AM1.5G and the light intensity is 100mw / cm 2 The Oriel 300W solar simulator was used as the light source to test the photoelectric performance of the laminated solar cells obtained in the above Examples 1 to 4 and Comparative Example 1. The JV curve was measured by a Keithly 2400 digital source meter, and the photoelectric performance test parameters were obtained, as shown in Table 1:

[0093] Table 1

[0094]

[0095] From the results in Table 1, it can be seen that compared with Comparative Example 1, the open circuit voltage Voc, short circuit current density Jsc, fill factor FF and conversion efficiency PCE of the stacked solar cells based on the multi-layer hole transport layer of Examples 1 to 2 are significantly improved, and the conversion efficiency PCE after 1000 hours of continuous illumination is also significantly improved, indicating that the second transport layer in the hole transport layer uses a cation-doped metal oxide SnO2:Sb film layer to replace the small molecule self-assembly layer SAMs film layer, and the photoelectric conversion efficiency is improved while also improving the stability of the solar cell. Compared with Comparative Example 2, the open circuit voltage Voc, short circuit current density Jsc, fill factor FF, conversion efficiency PCE of the single-cell solar cell based on the multi-layer hole transport layer of Example 3 are significantly improved, and the conversion efficiency PCE after 1000 hours of continuous illumination is also significantly improved, indicating that the multi-layer metal oxide hole transport layer in this application is suitable for stacked solar cells and single-cell solar cells.

[0096] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0097] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A perovskite solar cell, characterized in that: include: A substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer and a first electrode are sequentially stacked, wherein the hole transport layer includes at least one first transport layer and a second transport layer which are stacked, the material of the second transport layer includes a cation-doped metal oxide, and the second transport layer is located between the first transport layer and the perovskite absorption layer.

2. The perovskite solar cell according to claim 1, characterized in that The material of the metal oxide of the second transmission layer includes tin oxide.

3. The perovskite solar cell according to claim 2, characterized in that: The valence of the cation is less than or equal to 3.

4. The perovskite solar cell according to claim 1, characterized in that: The first transmission layer and the second transmission layer have different metal oxides.

5. The perovskite solar cell according to claim 1, characterized in that: The first transmission layer and the second transmission layer have different work functions.

6. The perovskite solar cell according to any one of claims 1 to 5, characterized in that: The thickness of the second transmission layer is 1 nm to 30 nm.

7. The perovskite solar cell according to any one of claims 1 to 5, characterized in that: The substrate comprises any one of FTO conductive glass, ITO conductive glass, AZO conductive glass, conductive flexible substrate and solar bottom cell.

8. A method for preparing a perovskite solar cell according to any one of claims 1 to 7, characterized in that: include: providing a substrate; A hole transport layer, a perovskite light absorbing layer, an electron transport layer, a buffer layer and an electrode are sequentially stacked on the surface of the substrate, wherein the hole transport layer includes at least one first transport layer and a second transport layer stacked in layers, the material of the second transport layer includes a cation-doped metal oxide, and the second transport layer is located between the first transport layer and the perovskite light absorbing layer.

9. The method for preparing a perovskite solar cell according to claim 8, characterized in that: The step of forming the second transmission layer comprises: A first metal oxide is deposited on the first transmission layer by a deposition process to form a second transmission layer, wherein the first metal oxide includes the cation-doped metal oxide.

10. The method for preparing a perovskite solar cell according to claim 8, characterized in that: The step of forming the second transmission layer comprises: A second metal oxide and a doping material are deposited together on the first transport layer by a deposition process to form a second transport layer, wherein the doping material contains doped cations.

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