Perovskite solar cell and preparation method thereof

Abstract

The application provides a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises, in sequence, a substrate, a first electrode layer, a lower nickel oxide layer, an upper nickel oxide layer and a perovskite layer. The lower nickel oxide layer and the upper nickel oxide layer both comprise NiO and Ni2O3. The content of Ni2O3 in the upper nickel oxide layer is greater than that in the lower nickel oxide layer. The upper nickel oxide layer with a greater concentration of Ni2O3 can not only improve the spreading effect of the perovskite precursor solution, thereby facilitating the preparation of a large-area and uniform and dense perovskite thin film, but also has a more excellent hole extraction speed, which improves the photoelectric conversion efficiency of the perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of perovskite solar cell technology, specifically to a perovskite solar cell and its fabrication method. Background Technology

[0002] With the increasing severity of global ecological and energy shortages, photovoltaic power generation has received widespread attention. Compared to traditional silicon-based solar cells, perovskite solar cells have advantages such as simple manufacturing processes, low cost, and the ability to create flexible devices. In just a few years, their efficiency has progressed to a level comparable to the efficiency breakthroughs achieved by silicon solar cells over decades, demonstrating enormous potential. This remarkable development is mainly attributed to the unique photoelectric properties of the perovskite material in the light-absorbing layer, such as a direct bandgap, a wide light absorption range, low exciton binding energy, long carrier diffusion length, long carrier stability, and bipolar carrier mobility. Perovskite solar cells include formal and inverted structures. Compared to the formal structure, the inverted structure exhibits easily mitigated hysteresis behavior and long-term stability, making it easier to achieve commercial applications. In the inverted structure, the hole transport layer is deposited before the perovskite layer; therefore, the surface properties of the hole transport layer directly affect the deposition quality of the perovskite layer.

[0003] Currently, the materials for the hole transport layer in inverted perovskite solar cells include poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid (PEDOT:PSS) and NiO. x P-type metal oxides such as CuO and MoO3 are used, but PEDOT:PSS is not only expensive but also hygroscopic, significantly accelerating the decomposition of the perovskite light-absorbing layer and seriously compromising battery stability. P-type metal oxides, on the other hand, are inexpensive and possess excellent chemical stability, making them a potential alternative to PEDOT:PSS. NiO is also used... x Inverted perovskite solar cells, which serve as hole transport layers, currently achieve the best photoelectric conversion efficiency.

[0004] However, NiO prepared by existing methods x The poor wettability of the layer surface is detrimental to the perovskite precursor solution on NiO. x The surface spreading effect of the layer makes it difficult to form a large-area, uniform, and dense perovskite film, thus failing to guarantee the photoelectric conversion efficiency of perovskite solar cells. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is how to improve the photoelectric conversion efficiency of inverted perovskite solar cells, thereby providing a perovskite solar cell and its preparation method.

[0006] This invention provides a perovskite solar cell, comprising a substrate, a first electrode layer, a lower nickel oxide layer, an upper nickel oxide layer, and a perovskite layer stacked sequentially. The lower nickel oxide layer and the upper nickel oxide layer both comprise NiO and Ni2O3, and the content of Ni2O3 in the upper nickel oxide layer is greater than the content of Ni2O3 in the lower nickel oxide layer.

[0007] Optionally, the content of Ni2O3 in the upper nickel oxide layer is greater than the content of NiO, and the content of Ni2O3 in the lower nickel oxide layer is less than the content of NiO.

[0008] Optionally, the content of Ni2O3 in the upper nickel oxide layer is 50%-70%; and the content of Ni2O3 in the lower nickel oxide layer is 20%-40%.

[0009] Optionally, the thickness of the upper nickel oxide layer is less than the thickness of the lower nickel oxide layer.

[0010] Optionally, the thickness of the upper nickel oxide layer is 0.5nm-10nm, and the thickness of the lower nickel oxide layer is 8nm-30nm.

[0011] The present invention also provides a method for fabricating a perovskite solar cell, comprising the following steps: providing a substrate; forming a first electrode layer on one side surface of the substrate; sequentially forming a lower nickel oxide layer and an upper nickel oxide layer on the side surface of the first electrode layer away from the substrate using a magnetron sputtering process, wherein the oxygen concentration in the vacuum chamber during the formation of the upper nickel oxide layer is greater than the oxygen concentration in the vacuum chamber during the formation of the lower nickel oxide layer; and forming a perovskite layer on the side surface of the upper nickel oxide layer away from the substrate.

[0012] Optionally, the target material is nickel oxide. During the formation of the lower nickel oxide layer and the upper nickel oxide layer, inert gas and oxygen are introduced into the vacuum chamber. The flow rate of the inert gas is constant. During the formation of the lower nickel oxide layer, the oxygen flow rate accounts for 0%-1.8% of the total gas flow rate, and during the formation of the upper nickel oxide layer, the oxygen flow rate accounts for 1.8%-10% of the total gas flow rate.

[0013] Optionally, the flow rate of the inert gas is 300 sccm-700 sccm, the oxygen flow rate is 0 sccm-12.6 sccm during the formation of the lower nickel oxide layer, and the oxygen flow rate is 5.4 sccm-70 sccm during the formation of the upper nickel oxide layer.

[0014] Optionally, during the formation of the lower nickel oxide layer and the upper nickel oxide layer, the deposition rate is: The first sputtering time for forming the lower nickel oxide layer is 50 min to 140 min, and the second sputtering time for forming the upper nickel oxide layer is 6 min to 30 min.

[0015] Optionally, during the formation of the lower nickel oxide layer and the upper nickel oxide layer, the sputtering power is 600W to 900W.

[0016] Optionally, the method for fabricating the perovskite solar cell further includes pre-sputtering the target material before forming the lower nickel oxide layer.

[0017] Optionally, the pre-sputtering time is 10-20 minutes.

[0018] The technical solution of this invention has the following advantages:

[0019] 1. The perovskite solar cell provided by this invention comprises a lower nickel oxide layer and an upper nickel oxide layer forming a hole transport layer. On one hand, the upper nickel oxide layer has a high concentration of Ni₂O₃, giving it high surface energy and thus low surface tension. This results in high wettability of the upper nickel oxide layer, which is beneficial for the spreading effect of the perovskite precursor solution and facilitates the formation of a large-area, uniform, and dense perovskite film, thereby improving the photoelectric conversion efficiency of the perovskite solar cell. On the other hand, the upper nickel oxide layer with a high Ni₂O₃ concentration exhibits a superior hole extraction rate, enabling the hole transport layer to more effectively extract and conduct holes, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0020] 2. The perovskite solar cell fabrication method provided by this invention employs magnetron sputtering to sequentially form a lower nickel oxide layer and an upper nickel oxide layer on the surface of the first electrode to prepare a hole transport layer. By limiting the oxygen concentration in the vacuum chamber during the formation of the upper nickel oxide layer to be greater than that during the formation of the lower nickel oxide layer, the Ni₂O₃ content in the upper nickel oxide layer is greater than that in the lower nickel oxide layer. The upper nickel oxide layer with a higher Ni₂O₃ concentration not only improves the spreading effect of the perovskite precursor solution, thus facilitating the fabrication of large-area and uniformly dense perovskite films, but also exhibits a superior hole extraction rate, all of which improve the photoelectric conversion efficiency of the perovskite solar cell. Furthermore, compared to solution methods, the magnetron sputtering process for preparing the hole transport layer is more suitable for large-scale production, which is beneficial for the industrialization of perovskite solar cells. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present invention;

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-Substrate; 2-First electrode layer; 3-Hole transport layer; 31-Lower nickel oxide layer; 32-Upper nickel oxide layer; 4-Perovskite layer; 5-Electron transport layer; 6-Second electrode layer. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. In the description of the present invention, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] See Figure 1 This embodiment provides a perovskite solar cell, comprising a substrate 1, a first electrode layer 2, a lower nickel oxide layer 31, an upper nickel oxide layer 32, a perovskite layer 4, an electron transport layer 5, and a second electrode layer 6, sequentially stacked. Both the lower nickel oxide layer 31 and the upper nickel oxide layer 32 comprise NiO and Ni2O3, with the Ni2O3 content in the upper nickel oxide layer 32 being greater than that in the lower nickel oxide layer 31. The lower nickel oxide layer 31 and the upper nickel oxide layer 32 constitute the hole transport layer 3. On one hand, the upper nickel oxide layer 32 has a higher concentration of Ni2O3, resulting in higher surface energy and therefore lower surface tension. This gives the upper nickel oxide layer 32 higher wettability, which is beneficial for the spreading effect of the perovskite precursor solution and facilitates the formation of a large-area, uniform, and dense perovskite thin film, thereby improving the photoelectric conversion efficiency of the perovskite solar cell. On the other hand, the upper nickel oxide layer 32 with a higher concentration of Ni2O3 has a better hole extraction rate, which enables the hole transport layer to extract and conduct holes more effectively, thereby improving the photoelectric conversion efficiency of perovskite solar cells.

[0027] Specifically, the content of Ni2O3 in the upper nickel oxide layer 32 is greater than the content of NiO, and the content of Ni2O3 in the lower nickel oxide layer 31 is less than the content of NiO. The content of Ni2O3 in the upper nickel oxide layer 32 is 50%-70%, and the content of NiO is 10%-30%; the content of Ni2O3 in the lower nickel oxide layer 31 is 20%-40%, and the content of NiO is 20%-50%. For example, the content of Ni2O3 in the upper nickel oxide layer 32 can be 50%, 60%, or 70%; and the content of Ni2O3 in the lower nickel oxide layer 31 can be 20%, 30%, or 40%.

[0028] It should be noted that, in this embodiment, the Ni2O3 content in the upper nickel oxide layer refers to the Ni content in Ni2O3. 3+ The molar amount of NiO is the ratio of the total molar amount of Ni in the upper nickel oxide layer. The NiO content in the upper nickel oxide layer refers to the amount of Ni in NiO. 2+ The molar amount of Ni is the ratio of the total molar amount of Ni in the upper nickel oxide layer to the total molar amount of Ni in the lower nickel oxide layer; the content of Ni2O3 in the lower nickel oxide layer refers to the amount of Ni in Ni2O3. 3+ The molar amount of NiO is the ratio of the total molar amount of Ni in the lower nickel oxide layer to the total molar amount of Ni in the lower nickel oxide layer. The NiO content in the lower nickel oxide layer refers to the amount of Ni in NiO. 2+ The ratio of the molar amount of Ni to the total molar amount of Ni in the lower nickel oxide layer.

[0029] Specifically, the thickness of the upper nickel oxide layer is less than the thickness of the lower nickel oxide layer. Further, the thickness of the upper nickel oxide layer 32 is 0.5 nm-10 nm, and the thickness of the lower nickel oxide layer 31 is 8 nm-30 nm. For example, the thickness of the upper nickel oxide layer 32 can be 0.5 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm, and the thickness of the lower nickel oxide layer 31 can be 8 nm, 10 nm, 13 nm, 15 nm, 18 nm, 20 nm, 23 nm, 25 nm, 28 nm, or 30 nm.

[0030] It is important to understand that the transmittance of Ni2O3 is lower than that of NiO. Excessive concentration of Ni2O3 in the lower nickel oxide layer 31 and the upper nickel oxide layer 32, or excessive thickness of the upper nickel oxide layer 32, will reduce the transmittance of the entire hole transport layer, thus affecting the light absorption of the perovskite layer and consequently the photoelectric conversion efficiency of the perovskite solar cell. Similarly, since the transmittance of Ni2O3 is lower than that of NiO, when the composition of the lower nickel oxide layer 31 is the same as that of the upper nickel oxide layer 32, the transmittance of the entire hole transport layer is low, reducing the amount of light irradiating the perovskite film and being absorbed by it, thereby reducing the photoelectric conversion efficiency of the perovskite solar cell. Furthermore, when only the upper nickel oxide layer 32 is provided without the lower nickel oxide layer 31, the hole transport layer is too thin to guarantee its hole transport effect, resulting in a low photoelectric conversion efficiency of the perovskite solar cell. In summary, the upper nickel oxide layer 32 with appropriate Ni2O3 concentration and thickness has high wettability. It works in conjunction with the lower nickel oxide layer 31 with high transmittance, so that the entire hole transport layer not only has high transmittance but also high wettability. This improves the quality of the perovskite film while ensuring the light absorption of the perovskite film, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0031] In this embodiment, the substrate 1 includes, but is not limited to, glass.

[0032] The material of the first electrode layer 2 includes, but is not limited to, fluorine-doped tin oxide (FTO).

[0033] The material of perovskite layer 4 is three-dimensional perovskite. The general structural formula of three-dimensional perovskite is ABX3, where A is a monovalent cation, B is a divalent cation, and X is a halide anion. Among them, A includes, but is not limited to, methylamino groups (MA). + ), formamidin group (FA) + or cesium ions (Cs) + B includes, but is not limited to, Pb. 2+ Sn 2+ Furthermore, the thickness of the perovskite layer is 300nm-800nm. For example, the thickness of the three-dimensional perovskite layer can be 300nm, 400nm, 500nm, 600nm, 700nm or 800nm.

[0034] The electron transport layer 5 is made of materials including, but not limited to, PCBM (fullerene derivative), C 60 The thickness of the electron transport layer is 10nm-30nm; for example, the thickness of the electron transport layer can be 10nm, 15nm, 20nm, 25nm or 30nm.

[0035] The second electrode layer 6 is a metal electrode or a non-metal electrode. The material of the metal electrode includes, but is not limited to, at least one of Al, Ag, Ni, Co, Au, Mo and Cr. The non-metal electrode includes, but is not limited to, a carbon electrode.

[0036] In this embodiment, a BCP (bath copper spirit) layer (not shown) is further included between the electron transport layer 5 and the second electrode layer 6. The thickness of the BCP layer is 3nm-7nm. For example, the thickness of the BCP layer can be 3nm, 3.5nm, 4nm, 4.5nm, 5nm, 5.5nm, 6.5nm or 7nm.

[0037] This embodiment also provides a method for fabricating a perovskite solar cell, comprising the following steps: providing a substrate; forming a first electrode layer on one side surface of the substrate; sequentially forming a lower nickel oxide layer and an upper nickel oxide layer on the side surface of the first electrode layer away from the substrate using a magnetron sputtering process, wherein the oxygen concentration in the vacuum chamber during the formation of the upper nickel oxide layer is greater than the oxygen concentration in the vacuum chamber during the formation of the lower nickel oxide layer; and forming a perovskite layer on the side surface of the upper nickel oxide layer away from the substrate.

[0038] The aforementioned method for fabricating perovskite solar cells, by limiting the oxygen concentration in the vacuum chamber during the formation of the upper nickel oxide layer to be greater than that during the formation of the lower nickel oxide layer, ensures that the Ni₂O₃ content in the upper nickel oxide layer is greater than that in the lower nickel oxide layer. This higher Ni₂O₃ concentration in the upper nickel oxide layer not only improves the spreading effect of the perovskite precursor solution, thus facilitating the fabrication of large-area and uniformly dense perovskite films, but also results in a superior hole extraction rate, all of which enhance the photoelectric conversion efficiency of the perovskite solar cell. Furthermore, compared to solution methods, magnetron sputtering is more suitable for large-scale production of the hole transport layer, which is beneficial for the industrialization of perovskite solar cells.

[0039] The following provides a clear and complete description of an exemplary method for fabricating perovskite solar cells.

[0040] Step S1: Provide substrate 1.

[0041] Step S2: Form a first electrode layer 2 on one side surface of the substrate 1. Specifically, the process for forming the first electrode layer on one side surface of the substrate includes, but is not limited to, magnetic sputtering or chemical vapor deposition. It should be understood that when the substrate is glass and the material of the first electrode layer is FTO, commercially available FTO conductive glass can be used directly.

[0042] Step S3: A hole transport layer 3 is formed on the surface of the first electrode layer 2 facing away from the substrate 1 using a magnetron sputtering process. Specifically, the steps for forming the hole transport layer 3 are as follows:

[0043] S31. The nickel oxide target is installed as the cathode in the vacuum chamber of the magnetron sputtering equipment. The substrate obtained in step S2 is located in the vacuum chamber and the first electrode layer 2 faces the target. The air pressure in the vacuum chamber is the initial vacuum level.

[0044] S32. Simultaneously introduce inert gas and oxygen into the vacuum chamber;

[0045] S33. After the air pressure in the vacuum chamber stabilizes, turn on the magnetron sputtering power supply to pre-sputter the target material to remove impurities from the target material surface.

[0046] S34. After pre-sputtering, the baffle is removed, thereby depositing a nickel oxide layer 31 on the surface of the first electrode layer 2.

[0047] S35. After the lower nickel oxide layer 31 is deposited to a preset thickness, the oxygen flow rate is increased to deposit an upper nickel oxide layer 32 on the surface of the lower nickel oxide layer 31. When the upper nickel oxide layer 32 is deposited to a preset thickness, the hole transport layer 3 is obtained.

[0048] In step S31, the initial vacuum degree is ≤4×10 -3 Pa; for example, the initial vacuum level can be 4 × 10⁻⁶ Pa. -3 Pa, 3.5 × 10 -3 Pa, 3×10 -3 Pa, 2.5 × 10 -3 Pa, 2×10 -3 Pa, 1.5×10 -3 Pa, 1×10 -3 Pa.

[0049] In steps S32-S35, the pressure in the vacuum chamber is less than 1 Pa, and the flow rate of the inert gas remains constant. The inert gas includes, but is not limited to, argon. During the formation of the lower nickel oxide layer in step S34, the oxygen flow rate accounts for 0-1.8% of the total gas flow rate. During the formation of the upper nickel oxide layer in step S35, the oxygen flow rate accounts for 1.8%-10% of the total gas flow rate. For example, the ratio of oxygen flow rate to total gas flow rate in step S34 can be 0, 0.3%, 0.5%, 0.8%, 1.0%, 1.3%, 1.5%, or 1.8%, and the ratio of oxygen flow rate to total gas flow rate in step S35 can be 1.8%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%.

[0050] Specifically, in steps S32-S35, the flow rate of the inert gas is 300 sccm-700 sccm, the oxygen flow rate is 0 sccm-12.6 sccm during the formation of the lower nickel oxide layer in step S34, and the oxygen flow rate is 5.4 sccm-70 sccm during the formation of the upper nickel oxide layer in step S35. For example, in steps S32-S35, the flow rate of the inert gas can be 300 sccm, 350 sccm, 400 sccm, 450 sccm, 500 sccm, 550 sccm, 600 sccm, 650 sccm, or 700 sccm; the oxygen flow rate in step S34 can be 0 sccm, 1.5 sccm, 3 sccm, 4.5 sccm, 6 sccm, 7 sccm, 8 sccm, 9 sccm, 10.5 sccm, or 12.6 sccm; and the oxygen flow rate in step S35 can be 5.4 sccm, 10.8 sccm, 21 sccm, 24 sccm, 28 sccm, 35 sccm, 40 sccm, 50 sccm, 60 sccm, or 70 sccm.

[0051] In steps S33-S35, the sputtering power is 600W to 900W. For example, the sputtering power is 600W, 650W, 700W, 750W, 800W, 850W, or 900W. Sputtering power is the main factor affecting the sputtering rate.

[0052] Specifically, in steps S34-S35, the deposition rate is... The first sputtering time for forming the lower nickel oxide layer is 50-140 minutes, and the second sputtering time for forming the upper nickel oxide layer is 6-30 minutes. For example, the deposition rate can be... The first sputtering time for forming the lower nickel oxide layer can be 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min or 140 min, and the second sputtering time for forming the upper nickel oxide layer can be 6 min, 8 min, 11 min, 15 min, 20 min, 25 min or 30 min.

[0053] Furthermore, the lower nickel oxide layer is formed continuously and uninterruptedly, and the upper nickel oxide layer is formed continuously and uninterruptedly, that is, the lower nickel oxide layer is obtained by continuous sputtering for a first sputtering time, and the upper nickel oxide layer is obtained by continuous sputtering for a second sputtering time.

[0054] In step S33, the pre-sputtering time is 10 min to 20 min; for example, the pre-sputtering time can be 10 min, 15 min or 20 min.

[0055] Step S4: A perovskite layer 4 is formed on the surface of the upper nickel oxide layer 32 facing away from the substrate 1. Specifically, the methods for forming the perovskite layer 4 include, but are not limited to, spin coating and coating methods. The spin coating method includes a one-step method (anti-solvent method) and a two-step method.

[0056] Step S5: An electron transport layer 5 is formed on the surface of the perovskite layer 4 facing away from the substrate 1. Specifically, the method for forming the electron transport layer 5 includes, but is not limited to, spin coating, coating method, and vacuum evaporation method. The preparation method can be selected according to the material of the electron transport layer 5.

[0057] Step S7: A second electrode layer 6 is formed on the surface of the electron transport layer 5 facing away from the substrate 1, resulting in... Figure 1 The perovskite solar cell shown. Specifically, methods for forming the second electrode layer include, but are not limited to, vacuum evaporation.

[0058] The following specific embodiments clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0059] Example 1

[0060] This embodiment provides a perovskite solar cell, the fabrication method of which includes the following steps:

[0061] FTO conductive glass is provided, with a size of 30cm×30cm. P1 is laser-scribed on the FTO conductive glass to form a pre-cut line on the surface of the FTO conductive glass.

[0062] Clean and dry the FTO conductive glass;

[0063] A hole transport layer is formed using magnetron sputtering. The specific steps for forming the hole transport layer include: a nickel oxide target is mounted on the cathode of the vacuum chamber of the magnetron sputtering equipment; FTO conductive glass is also located within the vacuum chamber and faces the target; the pressure within the vacuum chamber does not exceed 4 × 10⁻⁶. -3Pa; Argon gas is introduced into the vacuum chamber at a flow rate of 500 sccm; After the pressure in the vacuum chamber stabilizes, the magnetron sputtering RF power supply is turned on at a sputtering power of 750W, and the target material is pre-sputtered for 15 min; After the target material is pre-sputtered, continuous sputtering is performed for 70 min to form a 15 nm thick lower nickel oxide layer on the surface of the FTO conductive layer. The main components of the lower nickel oxide layer are NiO and Ni2O3, with NiO content of 48%, Ni2O3 content of 20%, and the remainder being Ni(OH)2 and other nickel-containing compounds; Oxygen is introduced into the vacuum chamber at a flow rate of 10 sccm, and continuous sputtering is performed for 12 min to obtain a 2 nm thick upper nickel oxide layer, with NiO content of 20%, Ni2O3 content of 50%, and the remainder being Ni(OH)2 and other nickel-containing compounds.

[0064] The large-area FTO conductive glass sputtered with nickel oxide is cut into small-area FTO conductive glass with a size of 1cm×1cm along the pre-cut line;

[0065] A 450 nm thick perovskite layer was formed on the surface of the nickel oxide layer using spin coating. The material of the perovskite layer was Cs. 0.15 FA 0.85 PbI3;

[0066] A 25 nm thick layer of C was sequentially deposited on the surface of the perovskite layer using a vacuum evaporation process. 60 The perovskite solar cell consists of a 5nm thick BCP layer and an 80nm thick second electrode layer, with the second electrode layer made of Cu.

[0067] Example 2

[0068] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that the thickness of the upper nickel oxide layer is 5 nm.

[0069] Example 3

[0070] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that the thickness of the upper nickel oxide layer is 10 nm.

[0071] Example 4

[0072] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that the thickness of the upper nickel oxide layer is 0.5 nm.

[0073] Example 5

[0074] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that: the content of Ni2O3 in the upper nickel oxide layer is 56%, the content of NiO is 17%, and the remainder is Ni(OH)2 and other nickel-containing compounds. The oxygen flow rate during the formation of the upper nickel oxide layer is 15 sccm.

[0075] Example 6

[0076] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that: the content of Ni2O3 in the upper nickel oxide layer is 61%, the content of NiO is 15%, and the remainder is Ni(OH)2 and other nickel-containing compounds. The oxygen flow rate during the formation of the upper nickel oxide layer is 20 sccm.

[0077] Example 7

[0078] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that: the content of Ni₂O₃ in the lower nickel oxide layer is 25%, the content of NiO is 44%, and the remainder is Ni(OH)₂ and other nickel-containing compounds. The oxygen flow rate during the formation of the lower nickel oxide layer is 2.5 sccm.

[0079] Example 8

[0080] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 1 in that: the content of Ni2O3 in the lower nickel oxide layer is 28%, the content of NiO is 42%, and the remainder is Ni(OH)2 and other nickel-containing compounds. The oxygen flow rate during the formation of the lower nickel oxide layer is 4 sccm.

[0081] Example 9

[0082] This embodiment provides a perovskite solar cell, which differs from the perovskite solar cell provided in Embodiment 2 in that the material of the perovskite layer is Cs. 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(I 0.9 Br 0.1 3.

[0083] Comparative Example 1

[0084] This comparative example provides a perovskite solar cell, which differs from the perovskite solar cell provided in Example 1 in that: the perovskite layer is prepared directly after the lower nickel oxide layer is formed, without forming the upper nickel oxide layer.

[0085] Comparative Example 2

[0086] This comparative example provides a perovskite solar cell, which differs from the perovskite solar cell provided in Example 7 in that: the perovskite layer is prepared directly after the lower nickel oxide layer is formed, without forming the upper nickel oxide layer.

[0087] Comparative Example 3

[0088] This comparative example provides a perovskite solar cell, which differs from the perovskite solar cell provided in Example 9 in that: the perovskite layer is prepared directly after the lower nickel oxide layer is formed, without forming the upper nickel oxide layer.

[0089] Experimental Example 1

[0090] The photoelectric conversion performance of the perovskite solar cells provided in Examples 1-9 and Comparative Examples 1-3 was tested, and the test results are shown in Table 1. Wherein, Voc represents the open-circuit voltage, PCE represents the photoelectric conversion efficiency, FF represents the fill factor, and Jsc represents the short-circuit current density.

[0091] Table 1

[0092] Voc(V) PCE (%) FF (%) <![CDATA[Jsc(mA / cm 2 )]]> Example 1 1.03 18.19 74.91 23.58 Example 2 1.05 18.96 76.78 23.52 Example 3 1.07 18.20 74.32 22.89 Example 4 1.01 18.11 75.50 23.76 Example 5 1.04 18.39 74.87 23.62 Example 6 1.06 19.16 76.25 23.71 Example 7 1.03 18.09 75.02 23.41 Example 8 1.04 18.22 75.13 23.32 Example 9 1.04 18.76 75.21 23.98 Comparative Example 1 0.95 16.74 74.30 23.72 Comparative Example 2 1.02 17.95 75.32 23.36 Comparative Example 3 1.00 17.24 75.40 22.87

[0093] As shown in Table 1, compared with Comparative Examples 1-3, the perovskite solar cells provided in Examples 1-9 have superior photoelectric conversion efficiency, especially with a significant improvement in open-circuit voltage.

[0094] Experimental Example 2

[0095] Wetting angle tests were performed on the hole transport layers in Examples 1-8 and Comparative Examples 1-2, and the test results are shown in Table 2.

[0096] Table 2

[0097] Wetting angle θ (°) Example 1 18° Example 2 16° Example 3 16° Example 4 19° Example 5 15° Example 6 9° Example 7 18° Example 8 17° Comparative Example 1 35° Comparative Example 2 29°

[0098] As shown in Table 2, the hole transport layers prepared in Examples 1-8 have excellent wettability, which can effectively improve the spreading effect of the perovskite precursor solution on the surface of the hole transport layer, improve the quality of the perovskite layer, and help improve the open circuit voltage.

[0099] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A perovskite solar cell, characterized by, The substrate, the first electrode layer, the lower nickel oxide layer, the upper nickel oxide layer and the perovskite layer are sequentially stacked, the lower nickel oxide layer and the upper nickel oxide layer each comprise NiO and Ni2O3, and the content of Ni2O3 in the upper nickel oxide layer is greater than the content of Ni2O3 in the lower nickel oxide layer.

2. The perovskite solar cell according to claim 1, characterized in that, The content of Ni2O3 in the upper nickel oxide layer is greater than the content of NiO, and the content of Ni2O3 in the lower nickel oxide layer is less than the content of NiO.

3. The perovskite solar cell according to claim 2, characterized in that, The content of Ni2O3 in the upper nickel oxide layer is 50%-70%, and the content of Ni2O3 in the lower nickel oxide layer is 20%-40%.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that, The thickness of the upper nickel oxide layer is less than the thickness of the lower nickel oxide layer.

5. The perovskite solar cell according to claim 4, characterized in that, The thickness of the upper nickel oxide layer is 0.5nm-10nm, and the thickness of the lower nickel oxide layer is 8nm-30nm.

6. A method for preparing a perovskite solar cell, characterized by, The method comprises the following steps: providing a substrate; forming a first electrode layer on one side surface of the substrate; forming a lower nickel oxide layer and an upper nickel oxide layer on the side surface of the first electrode layer away from the substrate by a magnetron sputtering process, and the oxygen concentration in the vacuum chamber during the formation of the upper nickel oxide layer is greater than the oxygen concentration in the vacuum chamber during the formation of the lower nickel oxide layer; forming a perovskite layer on the side surface of the upper nickel oxide layer away from the substrate.

7. The method of claim 6, wherein the perovskite solar cell is prepared by the steps of: The target material is nickel oxide, inert gas and oxygen are introduced into the vacuum chamber during the formation of the lower nickel oxide layer and the upper nickel oxide layer, the flow rate of the inert gas is constant, the oxygen flow rate accounts for 0%-1.8% of the total gas flow rate during the formation of the lower nickel oxide layer, and the oxygen flow rate accounts for 1.8%-10% of the total gas flow rate during the formation of the upper nickel oxide layer. 8.The method of claim 7, wherein the perovskite solar cell is prepared by the steps of: The flow rate of the inert gas is 300sccm-700sccm, the oxygen flow rate is 0sccm-12.6sccm during the formation of the lower nickel oxide layer, and the oxygen flow rate is 5.4sccm-70sccm during the formation of the upper nickel oxide layer.

9. The method of producing a perovskite solar cell according to any one of claims 6 to 8, characterized by, In the process of forming the lower nickel oxide layer and the upper nickel oxide layer, the deposition rate is The first sputtering time for forming the lower nickel oxide layer is 50 min-140 min, and the second sputtering time for forming the upper nickel oxide layer is 6 min-30 min. 10.The method of claim 7, wherein the perovskite solar cell is prepared by the steps of: During the formation of the lower nickel oxide layer and the upper nickel oxide layer, the sputtering power is 600W-900W.

Images