Method for forming a hole transport layer on a substrate surface, hole transport layer, solar cell and method for manufacturing the same, solar power generation assembly

Abstract

The present application provides a method for forming a hole transport layer on a substrate surface, a hole transport layer, a solar cell and its manufacturing method, and a photovoltaic assembly. The method for forming a hole transport layer on a substrate surface includes the steps of providing M target materials containing an inorganic hole transport material, and forming a hole transport layer on the substrate surface including at least N continuous sublayers using magnetron sputtering principle, where 2≦N≦M, and at least one of the M target materials is a doped target material further containing a doped material. The present application can improve the stability and consistency of the solar cell, and can also easily adjust the energy level structure of the hole transport layer in the solar cell, which is favorable to the matching and optimization of the energy level between the light absorption layer / hole transport layer.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and specifically relates to a method for forming a hole transport layer on a substrate surface, a hole transport layer, a solar cell and a method for manufacturing the same, and a solar power generation assembly.

Background Art

[0002] With the development of modern industry, the global energy shortage and environmental pollution problems are becoming increasingly prominent, and solar cells are being increasingly regarded as ideal renewable energy. A solar cell, also called a photovoltaic cell, is a device that directly converts light energy into electrical energy by means of the photovoltaic effect or the photochemical effect. A perovskite solar cell is a solar cell that uses a perovskite material as an absorption layer. It rapidly obtained a high energy conversion efficiency within several years after its birth and has attracted wide attention in recent years. At present, the energy conversion efficiency of perovskite solar cells has already exceeded 21%, but its stability is still an obstacle restricting its progress towards commercialization. Therefore, how to improve the stability of solar cells remains an urgent problem to be solved.

Summary of the Invention

[0003] The object of this application is to provide a method for forming a hole transport layer on a substrate surface, a hole transport layer, a solar cell and a method for manufacturing the same, and a solar power generation assembly, which can better improve the stability and consistency of solar cells, and can also easily adjust the energy level structure of the hole transport layer in the solar cell, thereby being advantageous for the alignment and optimization of the energy levels between the absorption layer / hole transport layer.

[0004] According to a first aspect of the present application, a method for forming a hole transport layer on a substrate surface is provided. The method includes providing M target materials containing an inorganic hole transport material, and forming a hole transport layer including at least N continuous sub-layers on the substrate surface by using the magnetron sputtering principle, where 2 ≤ N ≤ M, and at least one of the M target materials is a doped target material further containing a doping material.

[0005] The inventor of the present application first combines an inorganic hole transport material and a doping material to form a doped target material, and after atomizing each target material by using the magnetron sputtering principle, sprays them onto the substrate in sequence to form a hole transport layer. The method of the present application can also easily adjust the specific composition of the target material or replace the target material to form a required hole transport layer. Compared with the manufacturing method of coating film formation, the method for forming the hole transport layer of the present application is simple, and the stability and consistency of the obtained hole transport layer are higher. The method of the present application can easily and accurately adjust the composition of each target material according to actual needs (for example, adjusting the type and / or content of the inorganic hole transport material, the type and / or content of the doping material, etc.) to obtain a hole transport layer having a required energy level.

[0006] In any embodiment of the present application, the types of the inorganic hole transport materials of each target material are the same as each other.

[0007] In any embodiment of the present application, the inorganic hole transport material is a P-type semiconductor.

[0008] In any embodiment of the present application, the inorganic hole transport material is NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3. Optionally, the inorganic hole transport material is selected from NiO x .

[0009] In any embodiment of the present application, the types of the doping materials for each doping target material are the same as or different from each other.

[0010] In any embodiment of the present application, the doping materials for each doping target material are each independently NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, and are one or more selected therefrom.

[0011] In any embodiment of the present application, the first target material or the Mth target material is a doping target material, and the doping material contains at least KI.

[0012] In any embodiment of the present application, based on the mass of each doping target material, the total mass percentage content of the doping material in each doping target material ≦ 25%. Optionally, the total mass percentage content of the doping material in each doping target material is 0.1% - 25%.

[0013] In any embodiment of the present application, when the doping target material contains one or more of NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag, Ag2O, the mass percentage content of the doping material in the doping target material independently satisfies ≦ 15% respectively.

[0014] In any embodiment of the present application, when the doping target material contains one or two of MgO, KI, the mass percentage content of the doping material in the doping target material independently satisfies ≦ 20% respectively.

[0015] In any embodiment of the present application, when the doping target material contains one or two of MnO, MnO2, the mass percentage content of the doping material in the doping target material independently satisfies ≦ 10% respectively.

[0016] In any embodiment of the present application, when the doped target material contains one or both of Co and CoO, the mass percentage content of the doping material in the doped target material independently satisfies ≤ 8%.

[0017] In any embodiment of the present application, when the doped target material contains one or more of Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, the mass percentage content of the doping material in the doped target material independently satisfies ≤ 25%.

[0018] In any embodiment of the present application, the hole transport layer has an energy level that changes gradiently. By adjusting the type and / or content of the inorganic hole transport material of each target material, the type and / or content of the doping material, etc., parameters such as the bandgap width and the energy level of the lower end of the conduction band of each target material can be easily and accurately adjusted, so that the hole transport layer has one or more of a bandgap width and an energy level of the lower end of the conduction band that change gradiently (for example, increase or decrease gradiently), thereby improving the hole collection and transport capabilities of the hole transport layer.

[0019] In any embodiment of the present application, the hole transport layer has a bandgap width that changes gradiently, and the M target materials have a bandgap width that changes gradiently, and the absolute value of the difference in the bandgap widths of two adjacent target materials |ΔEg(TAG)| satisfies 0 eV ≤ |ΔEg(TAG)| ≤ 1.5 eV.

[0020] In any embodiment of the present application, the hole transport layer has an energy level of the lower end of the conduction band that changes gradiently, and the M target materials have an energy level of the lower end of the conduction band that changes gradiently, and the absolute value of the difference in the energy levels of the lower ends of the conduction bands of two adjacent target materials |ΔCBM(TAG)| satisfies 0 eV ≤ |ΔCBM(TAG)| ≤ 1.5 eV.

[0021] In any embodiment of the present application, the hole transport layer has a gradually changing bandgap width and a conduction band bottom energy level, and the M target materials have a gradually changing bandgap width and a conduction band bottom energy level. The absolute value of the difference in bandgap width |ΔEg(TAG)| between two adjacent target materials satisfies 0 eV ≤ |ΔEg(TAG)| ≤ 1.5 eV, and the absolute value of the difference in conduction band bottom energy level |ΔCBM(TAG)| between two adjacent target materials satisfies 0 eV ≤ |ΔCBM(TAG)| ≤ 1.5 eV.

[0022] In any embodiment of the present application, the substrate is a transparent electrode, a metal electrode, or a conductive carbon electrode. Optionally, the transparent electrode is an FTO conductive glass electrode or an ITO conductive glass electrode. Optionally, the metal electrode is one or two selected from a gold electrode, a silver electrode, an aluminum electrode, and a copper electrode.

[0023] In any embodiment of the present application, magnetron sputtering satisfies a sputtering pressure of 2×10 -3 mbar to 8×10 -3 mbar.

[0024] In any embodiment of the present application, magnetron sputtering satisfies a gas flow rate of 50 sccm to 250 sccm.

[0025] In any embodiment of the present application, magnetron sputtering satisfies a heating temperature of 0 °C to 200 °C.

[0026] In any embodiment of the present application, magnetron sputtering satisfies a sputtering power of 200 W to 13 KW.

[0027] In any embodiment of the present application, magnetron sputtering satisfies a target-substrate distance of 60 mm to 120 mm.

[0028] According to a second aspect of the present application, a hole transport layer for a solar cell is provided, the hole transport layer including at least N continuous sub-layers, where N ≥ 2, and wherein each sub-layer includes an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer further including a doping material.

[0029] The hole transport layer of the present application can have a gently varying energy level gradient, which is advantageous for the alignment and optimization of the energy levels between the light-absorbing layer and the hole transport layer, and is also advantageous for enhancing the performance of the solar cell. The positions such as the bandgap width and the lower energy level of the conduction band of the hole transport layer of the present application can all be adjusted, which is advantageous for improving the hole collection and transport capabilities of the hole transport layer.

[0030] In any embodiment of the present application, 2 ≤ N ≤ 10.

[0031] In any embodiment of the present application, the types of the inorganic hole transport materials of each sub-layer are the same as each other.

[0032] In any embodiment of the present application, the inorganic hole transport material is a P-type semiconductor.

[0033] In any embodiment of the present application, the inorganic hole transport material is NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3. Optionally, the inorganic hole transport material is NiO x selected from.

[0034] In any embodiment of the present application, the types of the doping materials of each sub-doped layer are the same as or different from each other.

[0035] In any embodiment of the present application, the doping materials of each sub-doped layer are each independently NiO xOne or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3.

[0036] In any embodiment of the present application, the first sub-layer or the Nth sub-layer is a sub-doped layer, and the doping material contains at least KI.

[0037] In any embodiment of the present application, based on the mass of each sub-doped layer, the total mass percentage content of the doping material in each sub-doped layer ≤ 25%. Optionally, the total mass percentage content of the doping material in each sub-doped layer is 0.1% - 25%.

[0038] In any embodiment of the present application, when the sub-doped layer contains one or more of NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag, Ag2O, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 15% respectively.

[0039] In any embodiment of the present application, when the sub-doped layer contains one or two of MgO, KI, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 20% respectively.

[0040] In any embodiment of the present application, when the sub-doped layer contains one or two of MnO, MnO2, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 10% respectively.

[0041] In any embodiment of the present application, when the sub-doped layer contains one or two of Co, CoO, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 8% respectively.

[0042] In any embodiment of the present application, when the sub-doped layer contains one or more of Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 25% respectively.

[0043] In any embodiment of the present application, the N sub-layers have a bandgap that increases or decreases gradually, and the absolute value of the difference in the bandgaps of two adjacent sub-layers, |ΔEg(HTL)|, satisfies 0 eV < |ΔEg(HTL)| ≤ 1.5 eV.

[0044] In any embodiment of the present application, the N sub-layers have a conduction band bottom energy level that increases or decreases gradually, and the absolute value of the difference in the conduction band bottom energy levels of two adjacent sub-layers, |ΔCBM(HTL)|, satisfies 0 eV < |ΔCBM(HTL)| ≤ 1.5 eV.

[0045] In any embodiment of the present application, the N sub-layers have a bandgap and a conduction band bottom energy level that increase or decrease gradually, the absolute value of the difference in the bandgaps of two adjacent sub-layers, |ΔEg(HTL)|, satisfies 0 eV < |ΔEg(HTL)| ≤ 1.5 eV, and the absolute value of the difference in the conduction band bottom energy levels of two adjacent sub-layers, |ΔCBM(HTL)|, satisfies 0 eV < |ΔCBM(HTL)| ≤ 1.5 eV.

[0046] In any embodiment of the present application, the total thickness of the hole transport layer is 5 nm to 150 nm. Optionally, the total thickness of the hole transport layer is 10 nm to 80 nm.

[0047] According to the third aspect of the present application, a solar cell is provided, and the solar cell includes a hole transport layer manufactured by the method of the first aspect of the present application or the hole transport layer of the second aspect of the present application.

[0048] According to a fourth aspect of the present application, a method for manufacturing a solar cell is provided, and the method includes a method for forming a hole transport layer on the surface of the substrate according to the first aspect of the present application.

[0049] According to a fifth aspect of the present application, a photovoltaic assembly is provided, and the photovoltaic assembly includes the solar cell according to the third aspect of the present application.

[0050] The solar cell of the present application includes a hole transport layer having a gently varying energy level gradient, which is advantageous for the energy level alignment and optimization between the light absorption layer and the hole transport layer, and is advantageous for improving the performance of the solar cell. The positions such as the band gap width and the lower energy level of the conduction band of the hole transport layer can all be adjusted, which is also advantageous for improving the hole collection and transport capabilities of the hole transport layer. Since the photovoltaic assembly of the present application includes the solar cell according to the present application, it has at least the same advantages as the solar cell.

Brief Description of the Drawings

[0051] To more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings that need to be used in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can also obtain other drawings based on these drawings on the premise of not paying creative efforts.

[0052]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0053] Hereinafter, embodiments specifically disclosing a method for forming a hole transport layer on the substrate surface of the present application, a hole transport layer, a solar cell and its manufacturing method, and a solar power generation assembly will be described in detail with appropriate reference to the drawings. However, detailed descriptions that are not necessary may be omitted. For example, detailed descriptions of well-known matters and duplicate descriptions of actually identical structures may be omitted. This is to avoid the following description from becoming unnecessarily long and to enable those skilled in the art to easily understand. Note that the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not for limiting the subject matter described in the claims.

[0054] The "range" disclosed in the present application is limited in the form of a lower limit and an upper limit, and a predetermined range is limited by selecting one lower limit and one upper limit that define the boundary of a specific range. The range thus limited may or may not include the end values and may be arbitrarily combined, that is, any lower limit and any upper limit may be combined to form a range. For example, when ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, ranges of 60 to 110 and 80 to 120 are also understood to be expected. Note that when the minimum range values 1 and 2, and the maximum range values 3, 4, and 5 are listed, all of the following 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 are expected. In the present application, unless otherwise specified, the numerical range "a to b" is a shortened expression representing all combinations of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 to 5" are listed in this specification, and "0 to 5" is merely an abbreviated representation of the combinations of these numerical values. Also, when it is described that a certain parameter is an integer ≧2, it is equivalent to disclosing that the parameter is, for example, the integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0055] Unless otherwise specifically described, all embodiments and optional embodiments of the present application may be combined with each other to form a new technical solution.

[0056] Unless otherwise specified, all technical features and optional technical features of this application may be combined with each other to form a new technical solution.

[0057] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the fact that the method includes steps (a) and (b) means that the method may include steps (a) and (b) performed in order, or steps (b) and (a) performed in order. For example, the fact that the method mentioned above may further include step (c) means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or steps (a), (c) and (b), or steps (c), (a) and (b), etc.

[0058] Unless otherwise specified, the terms "comprising" and "including" mentioned in this application are open-ended and may also be closed-ended. For example, the "comprising" and "including" may further comprise or include other components not listed, or may comprise or include only the listed components.

[0059] Unless otherwise specified, the term "or" in this application is inclusive. For example, the phrase "A or B" represents "A, B, or both A and B". More specifically, any one of the following conditions satisfies the condition of "A or B". A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), or both A and B are true (or exist).

[0060] As a clean and renewable energy source, solar energy has the advantage of being inexhaustible, so the research on solar energy occupies an important position in the energy strategy. Solar cells are being increasingly valued as ideal renewable energy sources. Currently, solar cells have developed from simple lighting fields to fields such as spaceflight, transportation, power, communication, portable and wearable integration.

[0061] The stability of solar cells remains an obstacle restricting their progress towards commercialization. Taking perovskite solar cells as an example, perovskite materials have poor stability and are prone to decomposition under humid environments and light irradiation conditions, which causes the energy conversion efficiency of solar cells to decrease and ultimately renders the solar cells ineffective. To improve the stability of solar cells, in addition to relying on improving the stability of the perovskite material itself, another feasible solution is to provide a hole transport layer with higher stability and consistency to suppress the decomposition of the perovskite material.

[0062] To obtain a hole transport layer with higher stability and consistency, the solution adopted in the prior art is to first perform coating and film formation and then perform high-temperature annealing to form the hole transport layer. However, the process flow of this manufacturing process is complex, the process window is narrow, the reaction conditions are strict, and it is necessary to accurately control the concentration of each component in the reaction solution. At the same time, since such a process is a single-piece single-lot manufacturing process, when manufacturing each piece, it is necessary to independently arrange the reaction solution, which deteriorates the consistency between samples of different lots. In addition, the coating and film formation manufacturing process further limits the application of large-scale large-size products. Method for forming a hole transport layer on a substrate surface

[0063] In view of the above problems, according to the first aspect of the embodiments of the present application, a method for forming a hole transport layer on a substrate surface is provided, which can achieve high stability and high consistency of the manufacturing process, and the energy level structure of the hole transport layer can be more easily adjusted. The method for forming a hole transport layer on the substrate surface includes providing M target materials including inorganic hole transport materials, and forming a hole transport layer including at least N continuous sub-layers on the substrate surface by using the magnetron sputtering principle, where 2≤N≤M, and at least one of the M target materials is a doped target material further including a doping material.

[0064] Magnetron sputtering may be performed in a magnetron sputtering chamber. The substrate is attached to the anode of the magnetron sputtering chamber, and the substrate can move forward by transmission. The M target materials are sequentially attached and fixed to the cathode of the magnetron sputtering chamber. During magnetron sputtering, when the substrate moves forward by transmission and passes through the first target material, a first sub-layer having the same composition as that of the first target material (including the types of each component and the content of each component) is formed on the substrate surface. As the substrate moves forward by transmission, a second sub-layer having the same composition as that of the second target material is continuously formed on the first sub-layer. By analogy in this way, it continues until an Nth sub-layer having the same composition as that of the Mth target material is formed on the (N - 1)th sub-layer, and 2≤N≤M.

[0065] M > N means that two or more adjacent target materials are the same as each other, and these target materials jointly form one sub-layer in the hole transport layer. For example, in order to increase the thickness of one sub-layer in the hole transport layer, the two adjacent target materials are set to be completely the same.

[0066] M = N represents that the M target materials and the N sub-layers correspond one-to-one. That is, the first target material is for forming the first sub-layer, the second target material is for forming the second sub-layer, and so on by analogy.

[0067] The inventor of the present application first combined an inorganic hole transport material and a doping material to form a doped target material. After atomizing each target material using the magnetron sputtering principle, they were sequentially sprayed onto a substrate to form a hole transport layer. The method of the present application can also easily adjust the specific composition of the target material or replace the target material to form a required hole transport layer. Compared with the manufacturing method of coating film formation, the method of forming the hole transport layer in the present application is simple, and the stability and consistency of the obtained hole transport layer are higher.

[0068] At least one of the M target materials further includes a doping material to form a doped target material. In some embodiments, M - 1 of the M target materials include a doping material to form a doped target material, and one of the M target materials does not include a doping material and is a non-doped target material. In some other embodiments, all of the M target materials include a doping material to form a doped target material.

[0069] The method of the present application can easily and accurately adjust the composition of each target material according to actual needs (for example, adjusting the type and / or content of the inorganic hole transport material, the type and / or content of the doping material, etc.) to obtain a hole transport layer having a required energy level.

[0070] By adjusting the composition of each target material (for example, adjusting the type and / or content of the inorganic hole transport material, the type and / or content of the doping material, etc.), it is also possible to endow the obtained hole transport layer with a gently varying energy level gradient, which is further advantageous for the energy level alignment and optimization between the light absorption layer and the hole transport layer, and is advantageous for improving the performance of the solar cell. By adjusting the composition of each target material (for example, adjusting the type and / or content of the inorganic hole transport material, the type and / or content of the doping material, etc.), it is also possible to easily and accurately adjust the bandgap width, the lower conduction band energy level, etc. of each target material, thereby improving the hole collection and transport capabilities of the hole transport layer.

[0071] The method of the present application can easily and accurately adjust the energy level structure of the hole transport layer according to actual needs, obtain a plurality of different hole transport layers, provide a very wide adjustment window for the optimization and design of the performance of the hole transport layer, further expand the possibility of optimizing the performance of the solar cell, and also increase the contribution degree of the hole transport layer when improving the performance of the solar cell.

[0072] The method of the present application can effectively increase the manufacturing process window of the hole transport layer and realize the process stability and consistency when mass-producing the hole transport layer.

[0073] The method of the present application can realize the manufacturing of large-scale large-size hole transport layers.

[0074] The method of the present application can realize the synchronization of the coating process and the annealing process of the hole transport layer and reduce the process flow.

[0075] The method of the present application can maintain the cleanliness of the obtained hole transport layer, which is further advantageous for improving the performance of the solar cell.

[0076] In the method of the present application, there are no problems such as the safety of organic solvents and environmental protection.

[0077] In some embodiments, N is a range composed of any numerical value from 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. Optionally, 2 ≤ N ≤ 10, 3 ≤ N ≤ 10, 4 ≤ N ≤ 10, 5 ≤ N ≤ 10, 2 ≤ N ≤ 9, 2 ≤ N ≤ 8, 2 ≤ N ≤ 7, 2 ≤ N ≤ 6, 2 ≤ N ≤ 5, or 2 ≤ N ≤ 5.

[0078] In some embodiments, each target material is introduced into the plasma generation spray of the magnetron sputtering chamber in a powdered form or in the form of a wire, and after being turned into plasma, it is sprayed onto the substrate in sequence to form a hole transport layer.

[0079] In some embodiments, the M target materials adopt a continuous arrangement method, an arranged method with intervals, or a method of being partially continuously arranged and partially arranged with intervals.

[0080] In some embodiments, the types of the inorganic hole transport materials of the target materials are the same as each other.

[0081] In some embodiments, the inorganic hole transport material may be a p-type semiconductor. As an example, the inorganic hole transport material is nickel oxide NiO x , one selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3. Optionally, the inorganic hole transport material is NiO x selected from.

[0082] In some embodiments, the types of the inorganic hole transport materials of the doped target materials are the same as each other, and the types of the doping materials are the same as or different from each other.

[0083] For example, in some embodiments, the types of the inorganic hole transport materials of the respective doped target materials are the same as each other, and the types of the doping materials are different from each other. In some other embodiments, the types of the inorganic hole transport materials of the respective doped target materials are the same as each other, and the types of the doping materials are not completely the same. For example, in each doped target material, there are at least one same doping material and at least one different doping material.

[0084] As an example, the doping material of each doped target material is independently NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, or a plurality of them selected therefrom.

[0085] In some embodiments, based on the mass of each doped target material, the total mass percentage content of the doping material of each doped target material ≤ 25%, for example, ≤ 24%, ≤ 23%, ≤ 22%, ≤ 21%, ≤ 20%, ≤ 19%, ≤ 18%, ≤ 17%, ≤ 16%, ≤ 15%, ≤ 14%, ≤ 13%, ≤ 12%, ≤ 11%, ≤ 10%, ≤ 9%, ≤ 8%, ≤ 7%, ≤ 6%, or ≤ 5%. Optionally, the total mass percentage content of the doping material of each doped target material is 0.1% - 25%, 0.1% - 22.5%, 0.1% - 20%, 0.1% - 17.5%, 0.1% - 15%, 0.1% - 12.5%, 0.1% - 10%, 0.1% - 7.5%, or 0.1% - 5%.

[0086] NiO x, CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3 may be used as inorganic hole transport materials or as doping materials for certain inorganic hole transport materials. The difference is that when used as an inorganic hole transport material, the mass percentage content in each target material (or doped target material) is high, for example, greater than 75%, optionally 75% - 100%, while when used as a doping material for a certain inorganic hole transport material, the mass percentage content in each doped target material is low, for example, ≤ 25%.

[0087] In some embodiments, when the doped target material contains one or more of NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag, Ag2O, the mass percentage content of the doping material in the doped target material independently satisfies ≤ 15% respectively. Here, NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag2O are here used as doping materials for a certain inorganic hole transport material in the target material.

[0088] In some embodiments, when the doped target material contains one or both of MgO and KI, the mass percentage content of the doping material in the doped target material independently satisfies ≤ 20% respectively.

[0089] In some embodiments, when the doped target material contains one or both of MnO and MnO2, the mass percentage content of the doping material in the doped target material independently satisfies ≤ 10% respectively. Here, MnO and MnO2 are here used as doping materials for a certain inorganic hole transport material in the target material.

[0090] In some embodiments, when the doped target material contains one or both of Co and CoO, the mass percentage content of the doping material in the doped target material independently satisfies ≤8%. Here, CoO is used as a doping material for a certain inorganic hole transport material in the target material.

[0091] In some embodiments, when the doped target material contains one or more of Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, the mass percentage content of the doping material in the doped target material independently satisfies ≤25%. Here, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3 are used as doping materials for a certain inorganic hole transport material in the target material.

[0092] The energy levels (such as the band gap, the lower energy level of the conduction band, etc.) of each target material can be obtained by adjusting the type and / or content of the inorganic hole transport material and / or the type and / or content of the doping material of each target material.

[0093] To obtain the required energy levels (such as the band gap, the lower energy level of the conduction band, etc.), the type and content of the doping material of each doped target material may be selected from the above doping materials and their contents according to the needs. The doping material may be one or a combination of multiple ones.

[0094] In some embodiments, the first target material or the Mth target material is a doped target material, and the doping material contains at least KI. In this case, the surface defects of the obtained hole transport layer can be reduced, and the deposition and crystallization of the subsequent perovskite material can be promoted.

[0095] In some embodiments, the hole transport layer has an energy level that changes gradually. For example, the hole transport layer satisfies having one or more of a gradually changing bandgap and the energy level of the lower end of the conduction band. By adjusting the type and / or content of the inorganic hole transport material of each target material, the type and / or content of the doping material, etc., parameters such as the bandgap and the energy level of the lower end of the conduction band of each target material can be easily and accurately adjusted, and the hole transport layer can be made to satisfy having one or more of a gradually changing (e.g., gradually increasing or decreasing) bandgap and the energy level of the lower end of the conduction band, thereby improving the hole collection and transport capabilities of the hole transport layer.

[0096] As an example, in some embodiments, the hole transport layer has a gradually changing bandgap, the M target materials have a gradually changing bandgap, and the absolute value |ΔEg(TAG)| of the difference in the bandgaps of two adjacent target materials satisfies 0eV ≤ |ΔEg(TAG)| ≤ 1.5eV. In some other embodiments, the hole transport layer has a gradually changing energy level of the lower end of the conduction band, the M target materials have a gradually changing energy level of the lower end of the conduction band, and the absolute value |ΔCBM(TAG)| of the difference in the energy levels of the lower ends of the conduction bands of two adjacent target materials satisfies 0eV ≤ |ΔCBM(TAG)| ≤ 1.5eV. In some further embodiments, the hole transport layer has a gradually changing bandgap and a gradually changing energy level of the lower end of the conduction band, the M target materials have a gradually changing bandgap and a gradually changing energy level of the lower end of the conduction band, the absolute value |ΔEg(TAG)| of the difference in the bandgaps of two adjacent target materials satisfies 0eV ≤ |ΔEg(TAG)| ≤ 1.5eV, and the absolute value |ΔCBM(TAG)| of the difference in the energy levels of the lower ends of the conduction bands of two adjacent target materials satisfies 0eV ≤ |ΔCBM(TAG)| ≤ 1.5eV.

[0097] In some embodiments, the magnetron sputtering may be pulsed magnetron sputtering, DC magnetron sputtering, RF magnetron sputtering, medium frequency magnetron sputtering, or composite magnetron sputtering.

[0098] In some embodiments, the magnetron sputtering satisfies that the sputtering pressure is 2×10 -3 mbar to 8×10 -3 mbar.

[0099] In some embodiments, the magnetron sputtering satisfies that the gas flow rate is 50 sccm to 250 sccm.

[0100] In some embodiments, the magnetron sputtering satisfies that the heating temperature is 0°C to 200°C.

[0101] In some embodiments, the magnetron sputtering satisfies that the sputtering power is 200 W to 13 KW.

[0102] In some embodiments, the magnetron sputtering satisfies that the target-substrate distance is 60 mm to 120 mm.

[0103] In some embodiments, the magnetron sputtering process may be performed under the conditions of a sputtering pressure of 2×10 -3 mbar to 8×10 -3 mbar, a gas flow rate of 50 sccm to 250 sccm, a heating temperature of 0°C to 200°C, a sputtering power of 200 W to 13 KW, and a target-substrate distance of 60 mm to 120 mm.

[0104] In some embodiments, the working gas for magnetron sputtering is one or two selected from O2 and Ar. Optionally, the volume ratio of O2 to Ar is 1% to 90%. The working gas corresponding to magnetron sputtering of each target material may be the same or different and may be selected according to actual requirements.

[0105] The magnetron sputtering conditions corresponding to each target material may be the same or different. For example, in order to increase or decrease the thickness of one sublayer in the hole transport layer, the sputtering power or sputtering air pressure of the one target material corresponding to the sublayer may be increased or decreased alone.

[0106] In some embodiments, the speed at which the substrate advances by transmission is 0.1 mm / s to 50 cm / s. The substrate may advance by transmission at a constant speed or at a non-constant speed. For example, in order to increase or decrease the thickness of one sublayer in the hole transport layer, the speed at which the substrate advances by transmission and passes through the one target material corresponding to the sublayer may be increased or decreased alone.

[0107] In some embodiments, the heating temperature for magnetron sputtering is 0°C to 200°C. When the heating temperature is low, after magnetron sputtering is completed, the obtained thin film can be annealed in air to remove the internal stress of the thin film and make the surface of the thin film flatter. When the heating temperature is high, the method of the present application can realize the synchronization of the coating process and the annealing process and reduce the process flow. Here, the stable temperature for annealing may be 250°C to 300°C.

[0108] This application is not particularly limited with respect to the type of the substrate, and may be selected according to actual needs. For example, in some embodiments, the substrate is a transparent electrode, a metal electrode, or a conductive carbon electrode. Optionally, the transparent electrode is an FTO (fluorine-doped tin dioxide, SnO2:F) conductive glass electrode, or an ITO (indium-doped tin dioxide, SnO2:In2O3) conductive glass electrode. Optionally, the metal electrode is one or more selected from a gold electrode, a silver electrode, an aluminum electrode, and a copper electrode.

[0109] In some embodiments, the method for forming a hole transport layer on the surface of the substrate includes providing M target materials including an inorganic hole transport material, and forming a hole transport layer including at least N continuous sub-layers on the surface of the substrate by using the magnetron sputtering principle, where 2 ≤ N ≤ M, and at least one of the M target materials is a doped target material further including a doping material. The types of the inorganic hole transport materials of the M target materials are the same as each other, and all are selected from NiO x and each doping material of each doped target material is independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3. And based on the mass of each doped target material, the total mass percentage content of the doping material in each doped target material ≤ 25%. The obtained hole transport layer has a bandgap that varies gradiently. The M target materials have a bandgap that varies gradiently, and the absolute value of the difference in bandgap |ΔEg(TAG)| between two adjacent target materials satisfies 0 eV ≤ |ΔEg(TAG)| ≤ 1.5 eV.

[0110] In some embodiments, the method for forming a hole transport layer on the substrate surface provides M target materials containing an inorganic hole transport material, and forms a hole transport layer including at least N continuous sub-layers on the substrate surface by utilizing the magnetron sputtering principle, where 2 ≤ N ≤ M, and at least one of the M target materials is a doped target material further containing a doping material. The types of the inorganic hole transport materials of the M target materials are the same as each other, and all are selected from NiO x and the doping materials of each doped target material are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3. And based on the mass of each doped target material, the total mass percentage content of the doping material in each doped target material ≤ 25%. The obtained hole transport layer has a conduction band lower edge energy level that changes gradually. The M target materials have a conduction band lower edge energy level that changes gradually, and the absolute value of the difference |ΔCBM(TAG)| between the conduction band lower edge energy levels of two adjacent target materials satisfies 0 eV ≤ |ΔCBM(TAG)| ≤ 1.5 eV.

[0111] In some embodiments, the method for forming a hole transport layer on the substrate surface provides M target materials containing an inorganic hole transport material, and forms a hole transport layer including at least N continuous sub-layers on the substrate surface by utilizing the magnetron sputtering principle, where 2 ≤ N ≤ M, and at least one of the M target materials is a doped target material further containing a doping material. The types of the inorganic hole transport materials of the M target materials are the same as each other, and all are selected from NiO xselected from, and the doping materials of each doping target material are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, and based on the mass of each doping target material, the total mass percentage content of the doping material of each doping target material ≦ 25%, the obtained hole transport layer has a bandgap width and a conduction band lower energy level that vary gradiently, the M target materials have a bandgap width and a conduction band lower energy level that vary gradiently, and the absolute value of the difference in the bandgap widths of two adjacent target materials |ΔEg(TAG)| satisfies 0eV ≦ |ΔEg(TAG)| ≦ 1.5eV, and the absolute value of the difference in the conduction band lower energy levels of two adjacent target materials |ΔCBM(TAG)| satisfies 0eV ≦ |ΔCBM(TAG)| ≦ 1.5eV. Hole transport layer

[0112] According to a second aspect of the embodiments of the present application, a hole transport layer for a solar cell is provided. The hole transport layer includes at least N continuous sub-layers, where N ≧ 2, and here, each sub-layer includes an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer that further includes a doping material.

[0113] In some embodiments, N - 1 of the N sub-layers include a doping material, and one sub-layer does not include a doping material. In some other embodiments, all of the N sub-layers include a doping material.

[0114] In some embodiments, N is in the range composed of any numerical value of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. Optionally, 2 ≦ N ≦ 10, 3 ≦ N ≦ 10, 4 ≦ N ≦ 10, 5 ≦ N ≦ 10, 2 ≦ N ≦ 9, 2 ≦ N ≦ 8, 2 ≦ N ≦ 7, 2 ≦ N ≦ 6, 2 ≦ N ≦ 5, or 2 ≦ N ≦ 5.

[0115] In some embodiments, the types of the inorganic hole transport materials of the respective sub-layers are the same as each other.

[0116] In some embodiments, the inorganic hole transport material may be a p-type semiconductor. For example, the inorganic hole transport material is nickel oxide NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3. Optionally, the inorganic hole transport material is selected from NiO x .

[0117] In some embodiments, the types of the inorganic hole transport materials of the respective sub-doped layers are the same as each other, and the types of the doping materials are the same as or different from each other.

[0118] For example, in some embodiments, the types of the inorganic hole transport materials of each sub-doped layer are the same as each other, and the types of the doping materials are different from each other. In some other embodiments, the types of the inorganic hole transport materials of each sub-doped layer are the same as each other, and the types of the doping materials are not completely the same. For example, in each sub-doped layer, there are at least one same doping material and at least one different doping material.

[0119] For example, the doping materials of the respective sub-doped layers are each independently NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, or one or more selected therefrom.

[0120] In some embodiments, based on the mass of each sub-doping layer, the total mass percentage content of the doping material in each sub-doping layer is ≤ 25%, for example, ≤ 24%, ≤ 23%, ≤ 22%, ≤ 21%, ≤ 20%, ≤ 19%, ≤ 18%, ≤ 17%, ≤ 16%, ≤ 15%, ≤ 14%, ≤ 13%, ≤ 12%, ≤ 11%, ≤ 10%, ≤ 9%, ≤ 8%, ≤ 7%, ≤ 6%, or ≤ 5%. Optionally, the total mass percentage content of the doping material in each sub-doping layer is 0.1% - 25%, 0.1% - 22.5%, 0.1% - 20%, 0.1% - 17.5%, 0.1% - 15%, 0.1% - 12.5%, 0.1% - 10%, 0.1% - 7.5%, or 0.1% - 5%.

[0121] NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3 may be used as inorganic hole transport materials or as doping materials for certain inorganic hole transport materials. The difference is that when used as an inorganic hole transport material, the mass percentage content in each sub-layer (or sub-doping layer) is high, for example, greater than 75%, optionally 75% - 100%, but when used as a doping material for certain inorganic hole transport materials, the mass percentage content in each sub-doping layer is low, for example, ≤ 25%.

[0122] In some embodiments, the sub-doping layer is NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag, Ag2O, when the sub-doping layer contains one or more of them, the mass percentage content of the doping material in the sub-doping layer respectively independently satisfies ≤ 15%. Here, NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag2O are here used as doping materials for certain inorganic hole transport materials in the sub-doping layer.

[0123] In some embodiments, when the sub-doping layer contains one or both of MgO and KI, the mass percentage content of the doping material in the sub-doping layer independently satisfies ≦20%.

[0124] In some embodiments, when the sub-doping layer contains one or both of MnO and MnO₂, the mass percentage content of the doping material in the sub-doping layer independently satisfies ≦10%. Here, MnO and MnO₂ are used as the doping materials for a certain inorganic hole transport material in the sub-doping layer.

[0125] In some embodiments, when the sub-doping layer contains one or both of Co and CoO, the mass percentage content of the doping material in the sub-doping layer independently satisfies ≦8%. Here, CoO is used as the doping material for a certain inorganic hole transport material in the sub-doping layer.

[0126] In some embodiments, when the sub-doping layer contains one or more of Li, Cs, Pb, In, Ga, Hg, Hg₂O, Cr₂O₃, SnO, SnS, PbO, Pr₂O₃, the mass percentage content of the doping material in the sub-doping layer independently satisfies ≦25%. Here, Hg₂O, Cr₂O₃, SnO, SnS, PbO, Pr₂O₃ are used as the doping materials for a certain inorganic hole transport material in the sub-doping layer.

[0127] The energy levels (e.g., band gap, conduction band bottom energy level, etc.) of each sub-layer can be obtained by adjusting the type and / or content of the inorganic hole transport material and / or the type and / or content of the doping material of each sub-layer.

[0128] To obtain the required energy levels (e.g., band gap, conduction band bottom energy level, etc.), the type and content of the doping material of each sub-doping layer may be selected from the above doping materials and their contents according to the needs. The doping material may be one or a combination of multiple ones.

[0129] In some embodiments, the first sub-layer or the Nth sub-layer is a sub-doped layer, and the doping material contains at least KI. In this case, the surface defects of the hole transport layer can be reduced, and the deposition and crystallization of the subsequent perovskite material can be promoted.

[0130] In some embodiments, the N sub-layers have gradually varying energy levels. For example, the N sub-layers satisfy having one or more of a gradually varying bandgap and the energy level of the lower end of the conduction band. By adjusting the type and / or content of the inorganic hole transport material and / or the type and / or content of the doping material in each sub-layer, the positions of the energy levels of each sub-layer and the hole transport layer (for example, the bandgap, the energy level of the lower end of the conduction band, etc.) can be adjusted, thereby better achieving the alignment and optimization of the energy levels between the light-absorbing layer / hole transport layer.

[0131] For example, in some embodiments, the N sub-layers have a gradually increasing or decreasing bandgap, and the absolute value of the difference in bandgap |ΔEg(HTL)| between two adjacent sub-layers satisfies 0eV < |ΔEg(HTL)| ≤ 1.5eV. In some other embodiments, the N sub-layers have a gradually increasing or decreasing energy level of the lower end of the conduction band, and the absolute value of the difference in the energy level of the lower end of the conduction band |ΔCBM(HTL)| between two adjacent sub-layers satisfies 0eV < |ΔCBM(HTL)| ≤ 1.5eV. In some further embodiments, the N sub-layers have a gradually increasing or decreasing bandgap and the energy level of the lower end of the conduction band, and the absolute value of the difference in bandgap |ΔEg(HTL)| between two adjacent sub-layers satisfies 0eV < |ΔEg(HTL)| ≤ 1.5eV, and the absolute value of the difference in the energy level of the lower end of the conduction band |ΔCBM(HTL)| between two adjacent sub-layers satisfies 0eV < |ΔCBM(HTL)| ≤ 1.5eV.

[0132] The hole transport layer of the present application can have a gently changing energy level gradient, which is advantageous for the alignment and optimization of the energy levels between the light-absorbing layer and the hole transport layer, and is also advantageous for improving the performance of the solar cell. The positions such as the band gap width and the lower energy level of the conduction band of the hole transport layer of the present application can all be adjusted, which is advantageous for improving the hole collection and transport capabilities of the hole transport layer.

[0133] In some embodiments, the total thickness of the hole transport layer is 5 nm to 150 nm. Optionally, the total thickness of the hole transport layer is 10 nm to 80 nm. Here, the thicknesses of each sub-layer are the same or different.

[0134] By using an X-ray photoelectron spectrometer (XPS) or an ultraviolet photoelectron spectrometer (UPS), the energy band distribution of each sub-layer and the hole transport layer can be obtained.

[0135] In some embodiments, the hole transport layer includes at least N continuous sub-layers, where 2 ≤ N ≤ 10. Each sub-layer includes an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer further including a doping material. The types of the inorganic hole transport materials of the N sub-layers are the same as each other, and all are selected from x NiO. The doping materials of each sub-doped layer are each independently selected from one or more of CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3. And based on the mass of each sub-doped layer, the total mass percentage content of the doping materials in each sub-doped layer ≤ 25%. The N sub-layers have a band gap width that increases or decreases gradiently, and the absolute value of the difference in the band gap widths of two adjacent sub-layers |ΔEg(HTL)| satisfies 0 eV < |ΔEg(HTL)| ≤ 1.5 eV.

[0136] In some embodiments, the hole transport layer includes at least N continuous sub-layers, where 2 ≤ N ≤ 10. Each sub-layer contains an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer further containing a doping material. The types of the inorganic hole transport materials in the N sub-layers are the same as each other, and all are NiO x selected from x . The doping materials of each sub-doped layer are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3. And based on the mass of each sub-doped layer, the total mass percentage content of the doping material in each sub-doped layer ≤ 25%. The N sub-layers have a conduction band bottom energy level that increases or decreases gradiently, and the absolute value of the difference in the conduction band bottom energy levels of two adjacent sub-layers |ΔCBM(HTL)| satisfies 0 eV < |ΔCBM(HTL)| ≤ 1.5 eV.

[0137] In some embodiments, the hole transport layer includes at least N continuous sub-layers, where 2 ≤ N ≤ 10. Each sub-layer contains an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer further containing a doping material. The types of the inorganic hole transport materials in the N sub-layers are the same as each other, and all are NiO xselected from, and the doping materials of each sub-doping layer are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, and based on the mass of each sub-doping layer, the total mass percentage content of the doping materials of each sub-doping layer ≦ 25%, and the N sub-layers have a bandgap and a conduction band bottom energy level that increase or decrease gradiently, and the absolute value of the difference in bandgap between two adjacent sub-layers |ΔEg(HTL)| satisfies 0eV < |ΔEg(HTL)| ≦ 1.5eV, and the absolute value of the difference in conduction band bottom energy level between two adjacent sub-layers |ΔCBM(HTL)| satisfies 0eV < |ΔCBM(HTL)| ≦ 1.5eV. Solar cell

[0138] According to a third aspect of the embodiments of the present application, a solar cell is provided, and the solar cell includes a hole transport layer manufactured by the method of the first aspect of the embodiments of the present application, or the hole transport layer of the second aspect of the embodiments of the present application.

[0139] The solar cell of the present application further includes a front electrode, a back electrode, an absorption layer, and an electron transport layer. Here, the hole transport layer, the absorption layer, and the electron transport layer are located between the front electrode and the back electrode, and the absorption layer is located between the electron transport layer and the hole transport layer.

[0140] Next, the solar cell of the third aspect of the embodiments of the present application will be described in conjunction with the drawings.

[0141] Figure 1 is a schematic structural diagram of an embodiment of the solar cell of the present application. As shown in Figure 1, the solar cell includes a front electrode 10, a hole transport layer 20, a light absorption layer 30, an electron transport layer 40, and a back electrode 50, which are installed in sequence. Figure 2 is a schematic structural diagram of another embodiment of the solar cell of the present application. As shown in Figure 2, the solar cell includes a front electrode 10, an electron transport layer 40, a light absorption layer 30, a hole transport layer 20, and a back electrode 50, which are installed in sequence. The hole transport layer 20 includes N continuous sub-layers, where N ≥ 2, and each sub-layer contains an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer that further contains a doping material. The first sub-layer is installed away from the light absorption layer 30, and the Nth sub-layer is installed close to the light absorption layer 30.

[0142] In some embodiments, N - 1 of the N sub-layers contain a doping material, and one sub-layer does not contain a doping material. In some other embodiments, all of the N sub-layers contain a doping material.

[0143] In some embodiments, N is in the range composed of any numerical value of 2, 3, 4, 5, 6, 7, 8, 9, 10, or more. Optionally, 2 ≤ N ≤ 10, 3 ≤ N ≤ 10, 4 ≤ N ≤ 10, 5 ≤ N ≤ 10, 2 ≤ N ≤ 9, 2 ≤ N ≤ 8, 2 ≤ N ≤ 7, 2 ≤ N ≤ 6, 2 ≤ N ≤ 5, or 2 ≤ N ≤ 5.

[0144] In some embodiments, the types of the inorganic hole transport materials of the respective sub-layers are the same as each other.

[0145] In some embodiments, the inorganic hole transport material may be a P-type semiconductor. By way of example, the inorganic hole transport material is nickel oxide NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3. Optionally, the inorganic hole transport material is selected from NiO x .

[0146] In some embodiments, the types of the inorganic hole transport materials of the sub-doping layers are the same as each other, and the types of the doping materials are the same as or different from each other.

[0147] For example, in some embodiments, the types of the inorganic hole transport materials of the sub-doping layers are the same as each other, and the types of the doping materials are different from each other. In some other embodiments, the types of the inorganic hole transport materials of the sub-doping layers are the same as each other, and the types of the doping materials are not completely the same. For example, in each sub-doping layer, there are at least one same doping material and at least one different doping material.

[0148] As an example, the doping materials of the sub-doping layers are each independently NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, or a combination thereof.

[0149] In some embodiments, based on the mass of each sub-doping layer, the total mass percentage content of the doping material in each sub-doping layer is ≤ 25%, for example, ≤ 24%, ≤ 23%, ≤ 22%, ≤ 21%, ≤ 20%, ≤ 19%, ≤ 18%, ≤ 17%, ≤ 16%, ≤ 15%, ≤ 14%, ≤ 13%, ≤ 12%, ≤ 11%, ≤ 10%, ≤ 9%, ≤ 8%, ≤ 7%, ≤ 6%, or ≤ 5%. Optionally, the total mass percentage content of the doping material in each sub-doping layer is 0.1% - 25%, 0.1% - 22.5%, 0.1% - 20%, 0.1% - 17.5%, 0.1% - 15%, 0.1% - 12.5%, 0.1% - 10%, 0.1% - 7.5%, or 0.1% - 5%.

[0150] NiO x, CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, CoO, Cr2O3, SnO, SnS, Hg2O, PbO, Ag2O, MnO, MnO2, Pr2O3 may be used as inorganic hole transport materials or as doping materials for certain inorganic hole transport materials. The difference is that when used as an inorganic hole transport material, the mass percentage content in each sub-layer (or sub-doping layer) is high, for example, greater than 75%, optionally 75% - 100%, but when used as a doping material for a certain inorganic hole transport material, the mass percentage content in each sub-doping layer is low, for example, ≤ 25%.

[0151] In some embodiments, the sub-doping layer is NiO x , when including one or more of CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag, Ag2O, the mass percentage content of the doping material in the sub-doping layer each independently satisfies ≤ 15%. Here, NiO x , CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, Ag2O are here used as doping materials for a certain inorganic hole transport material in the sub-doping layer.

[0152] In some embodiments, when the sub-doping layer includes one or two of MgO, KI, the mass percentage content of the doping material in the sub-doping layer each independently satisfies ≤ 20%.

[0153] In some embodiments, when the sub-doping layer includes one or two of MnO, MnO2, the mass percentage content of the doping material in the sub-doping layer each independently satisfies ≤ 10%. Here, MnO, MnO2 are here used as doping materials for a certain inorganic hole transport material in the sub-doping layer.

[0154] In some embodiments, when the sub-doped layer contains one or both of Co and CoO, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 8%. Here, CoO is used as the doping material for a certain inorganic hole transport material in the sub-doped layer.

[0155] In some embodiments, when the sub-doped layer contains one or more of Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, the mass percentage content of the doping material in the sub-doped layer independently satisfies ≤ 25%. Here, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3 are used as the doping materials for a certain inorganic hole transport material in the sub-doped layer.

[0156] The energy levels of each sub-layer (e.g., band gap, conduction band bottom energy level, etc.) can be obtained by adjusting the type and / or content of the inorganic hole transport material and / or the type and / or content of the doping material of each sub-layer.

[0157] To obtain the required energy levels (e.g., band gap, conduction band bottom energy level, etc.), the type and content of the doping material of each sub-doped layer may be selected from the above doping materials and their contents according to the needs. The doping material may be one or a combination of multiple ones.

[0158] In some embodiments, the Nth sub-layer is a sub-doped layer, and the doping material contains at least KI. In this case, the surface defects of the hole transport layer can be reduced, and the deposition and crystallization of the subsequent perovskite material can be promoted.

[0159] In some embodiments, the N sub-layers have gradually varying energy levels. For example, the N sub-layers satisfy having one or more of a gradually varying bandgap and the conduction band bottom energy level. By adjusting the type and / or content of the inorganic hole transport material and / or the type and / or content of the doping material of each sub-layer, the positions of the energy levels of each sub-layer and the hole transport layer (e.g., bandgap, conduction band bottom energy level, etc.) can be adjusted, thereby better achieving the alignment and optimization of the energy levels between the light-absorbing layer and the hole transport layer.

[0160] In some embodiments, along the direction from the Nth sub-layer to the first sub-layer, the N sub-layers have a gradually increasing bandgap, and the absolute value of the difference in the bandgaps of two adjacent sub-layers, |ΔEg(HTL)|, satisfies 0eV < |ΔEg(HTL)| ≦ 1.5eV. In some other embodiments, along the direction from the Nth sub-layer to the first sub-layer, the N sub-layers have a gradually increasing conduction band bottom energy level, and the absolute value of the difference in the conduction band bottom energy levels of two adjacent sub-layers, |ΔCBM(HTL)|, satisfies 0eV < |ΔCBM(HTL)| ≦ 1.5eV. In some further embodiments, along the direction from the Nth sub-layer to the first sub-layer, the N sub-layers have a gradually increasing bandgap and conduction band bottom energy level, the absolute value of the difference in the bandgaps of two adjacent sub-layers, |ΔEg(HTL)|, satisfies 0eV < |ΔEg(HTL)| ≦ 1.5eV, and the absolute value of the difference in the conduction band bottom energy levels of two adjacent sub-layers, |ΔCBM(HTL)|, satisfies 0eV < |ΔCBM(HTL)| ≦ 1.5eV.

[0161] Specifically, the lower conduction band edge energy level of the first sub-layer is CBM1, the upper valence band edge energy level is VBM1, and the band gap ΔEg1 = CBM1 - VBM1. The lower conduction band edge energy level of the second sub-layer is CBM2, the upper valence band edge energy level is VBM2, and the band gap ΔEg2 = CBM2 - VBM2, ……, the lower conduction band edge energy level of the Nth sub-layer is CBM n and the upper valence band edge energy level is VBM n and the band gap ΔEg n = CBM n - VBM n .

[0162] In some embodiments, ΔEg1, ΔEg2, ……, ΔEg n decrease in sequence, and 0eV < ΔEg i - ΔEg i+1 ≦ 1.5eV, and 1 ≦ i ≦ N - 1. In some other embodiments, CBM1, CBM2, ……, CBM n decrease in sequence, and 0eV < CBM i - CBM i+1 ≦ 1.5eV, and 1 ≦ i ≦ N - 1. In some other embodiments, ΔEg1, ΔEg2, ……, ΔEg n decrease in sequence, CBM1, CBM2, ……, CBM n decrease in sequence, and 0eV < ΔEg i - ΔEg i+1 ≦ 1.5eV, 0eV < CBM i - CBM i+1 ≦ 1.5eV, and 1 ≦ i ≦ N - 1.

[0163] The solar cell of the present application includes a hole transport layer having a gently varying energy level gradient, which is advantageous for the energy level alignment and optimization between the light absorption layer and the hole transport layer, and is advantageous for improving the performance of the solar cell. The positions such as the band gap and the lower conduction band edge energy level of the hole transport layer can all be adjusted, which is also advantageous for improving the hole collection and transport capabilities of the hole transport layer.

[0164] In some embodiments, the total thickness of the hole transport layer 20 is from 5 nm to 150 nm. Optionally, the total thickness of the hole transport layer 20 is from 10 nm to 80 nm. Here, the thicknesses of the respective sub-layers in the hole transport layer 20 are the same or different.

[0165] In some embodiments, the light absorption layer 30 includes a perovskite material. Since the perovskite material can transport electrons and holes as an intrinsic semiconductor material, it can function as a light absorption layer in a solar cell and can also function as an electron transport layer or a hole transport layer. The type of the perovskite material is not specifically limited and may be selected according to actual needs. In some embodiments, the perovskite material may include one or more of an inorganic halide perovskite material, an organic halide perovskite material, and an organic-inorganic hybrid halide perovskite material. The molecular formula of the perovskite material may be ABX3, where A represents an inorganic cation, an organic cation, or an organic-inorganic hybrid cation, B represents an inorganic cation, an organic cation, or an organic-inorganic hybrid cation, and X represents an inorganic anion, an organic anion, or an organic-inorganic hybrid anion.

[0166] By way of example, A may be CH3NH3 + (MA + )、CH(NH2)2 + (FA + )、Li + 、Na + 、K + 、Rb + 、Cs + selected from one or more of them. Optionally, A is one or more selected from CH3NH3 + 、CH(NH2)2 + 、Cs + selected from one or more of them,

[0167] By way of example, B is Pb 2+ 、Sn 2+ 、Be 2+ 、Mg 2+ 、Ca 2+ 、Sr 2+, Ba 2+ , Zn 2+ , Ge 2+ , Fe 2+ , Co 2+ , Ni 2+ It is one or more selected from. Optionally, B is Pb 2+ , Sn 2+ One or two selected from,

[0168] As an example, X is F - , Cl - , Br - , I - One or more selected from. Optionally, X is Cl - , Br - , I - One or more selected from.

[0169] In some embodiments, the perovskite material includes, but is not limited to, one or more of CH3NH3PbI3 (MAPbI3), CH(NH2)2PbI3 (FAPbI3), CsPbI3, CsPbI2Br, CsPbIBr2.

[0170] In some embodiments, the thickness of the light-absorbing layer 30 is not specifically limited and may be selected according to actual needs. For example, the thickness of the light-absorbing layer 30 is 150 nm to 1000 nm. Optionally, the thickness of the light-absorbing layer 30 is 300 nm to 700 nm.

[0171] In some embodiments, the electron transport layer 40 includes an electron transport material. The electron transport material of the electron transport layer 40 is not specifically limited and may be selected according to actual needs. For example, the electron transport material is selected from an organic electron transport material, an inorganic electron transport material, or an organic-inorganic hybrid electron transport material.

[0172] As an example, the electron transport material is at least one selected from imide compounds, quinone-based compounds, fullerenes and their derivatives, 2,2’,7,7’-tetrakis(N,N-p-methoxyaniline)-9,9’-spirobifluorene (Spiro-OMeTAD), methoxytriphenylamine-fluoromethamidine (OMeTPA-FA), poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (PEDOT:PSS), poly-3-hexylthiophene (P3HT), triphenylamine (H101) with triphenylene as the core, 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-aniline)carbazole-spirobifluorene (CzPAF-SBF), polythiophene, metal oxides (the metal element is selected from Mg, Ni, Cd, Zn, In, Pb, Mo, W, Sb, Bi, Cu, Hg, Ti, Ag, Mn, Fe, V, Sn, Zr, Sr, Ga, or Cr), silicon oxide (SiO2), strontium titanate (SrTiO3), calcium titanate (CaTiO3), lithium fluoride (LiF), calcium fluoride (CaF2), cuprous thiocyanate (CuSCN).

[0173] Optionally, the electron transport material is one or more selected from fullerenes and their derivatives. For example, the electron transport material is PC 60 BM, PC 70 BM. The energy levels of fullerenes and their derivatives can be better matched with the energy levels of the light absorption layer, which is advantageous for promoting the extraction and transport of electrons.

[0174] In some embodiments, the thickness of the electron transport layer 40 is not specifically limited and may be selected according to actual needs. For example, the thickness of the electron transport layer 40 is 20 nm to 200 nm.

[0175] In some embodiments, at least one of the front electrode 10 and the back electrode 50 is a transparent electrode. By way of example, the transparent electrode is an FTO (fluorine-doped tin dioxide, SnO2:F) conductive glass electrode or an ITO (indium-doped tin dioxide, SnO2:In2O3) conductive glass electrode.

[0176] In some embodiments, one of the front electrode 10 and the back electrode 50 is a metal electrode or a conductive carbon electrode. By way of example, the metal electrode is one or more selected from a gold electrode, a silver electrode, an aluminum electrode, and a copper electrode.

[0177] In some embodiments, the thickness of the front electrode 10 is not specifically limited and may be selected according to actual needs. For example, the thickness of the front electrode 10 is 10 nm to 650 nm.

[0178] In some embodiments, the thickness of the back electrode 50 is not specifically limited and may be selected according to actual needs. For example, the thickness of the back electrode 50 is 10 nm to 650 nm.

[0179] The solar cell of the present application is not limited to the above structure and may further include other functional layers. For example, in some embodiments, the solar cell further includes a hole blocking layer located between the light absorption layer 30 and the electron transport layer 40. In some other embodiments, the solar cell further includes an electrode modification layer for modifying the front electrode 10 or the back electrode 50, and the electrode modification layer can reduce the energy level barrier between the light absorption layer 30 and the front electrode 10 or the back electrode 50 and play a role in transporting holes and blocking electrons or transporting electrons and blocking holes.

[0180] By using an X-ray photoelectron spectrometer (XPS) or an ultraviolet photoelectron spectrometer (UPS), the energy band distribution of each film layer can be obtained.

[0181] In some embodiments, the solar cell includes a front electrode, a back electrode, a hole transport layer, a light absorption layer, and an electron transport layer. The hole transport layer, the light absorption layer, and the electron transport layer are located between the front electrode and the back electrode. The light absorption layer is located between the electron transport layer and the hole transport layer. The hole transport layer includes N continuous sub-layers, where 2 ≤ N ≤ 10. Each sub-layer includes an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer further including a doping material. The types of the inorganic hole transport materials of the N sub-layers are the same as each other and are all NiO x selected from x . The doping materials of each sub-doped layer are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3. And based on the mass of each sub-doped layer, the total mass percentage content of the doping material in each sub-doped layer ≤ 25%. The first sub-layer is disposed away from the light absorption layer, and the Nth sub-layer is disposed close to the light absorption layer. Along the direction from the Nth sub-layer to the first sub-layer, the N sub-layers have a gradually increasing bandgap, and the absolute value of the difference in bandgap |ΔEg(HTL)| between two adjacent sub-layers satisfies 0eV < |ΔEg(HTL)| ≤ 1.5eV.

[0182] In some embodiments, the solar cell includes a front electrode, a back electrode, a hole transport layer, a light absorption layer, and an electron transport layer. The hole transport layer, the light absorption layer, and the electron transport layer are located between the front electrode and the back electrode. The light absorption layer is located between the electron transport layer and the hole transport layer. The hole transport layer includes N continuous sub-layers, where 2 ≤ N ≤ 10. Each sub-layer includes an inorganic hole transport material, and at least one of the N sub-layers is a sub-doped layer further including a doping material. The types of the inorganic hole transport materials of the N sub-layers are the same as each other and are all NiO xselected from, and the doping materials of each sub-doping layer are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, and based on the mass of each sub-doping layer, the total mass percentage content of the doping material of each sub-doping layer ≦ 25%, the first sub-layer is installed away from the light absorption layer, the Nth sub-layer is installed close to the light absorption layer, along the direction from the Nth sub-layer to the first sub-layer, the N sub-layers have a conduction band lower energy level that increases gradiently, and the absolute value of the difference in the conduction band lower energy levels of two adjacent sub-layers |ΔCBM(HTL)| satisfies 0eV < |ΔCBM(HTL)| ≦ 1.5eV.

[0183] In some embodiments, the solar cell includes a front electrode, a back electrode, a hole transport layer, a light absorption layer, and an electron transport layer. The hole transport layer, the light absorption layer, and the electron transport layer are located between the front electrode and the back electrode. The light absorption layer is located between the electron transport layer and the hole transport layer. The hole transport layer includes N continuous sub-layers, where 2 ≦ N ≦ 10. Each sub-layer includes an inorganic hole transport material, and at least one of the N sub-layers is a sub-doping layer that further includes a doping material. The types of the inorganic hole transport materials of the N sub-layers are the same as each other and are all NiO xselected from, and the doping materials of each sub-doping layer are each independently one or more selected from CuO, Cu2O, Cu2S, CuI, CuSCN, CuGaO2, MgO, MnO, MnO2, Ag, Ag2O, Co, CoO, KI, Li, Cs, Pb, In, Ga, Hg, Hg2O, Cr2O3, SnO, SnS, PbO, Pr2O3, and based on the mass of each sub-doping layer, the total mass percentage content of the doping material of each sub-doping layer ≦ 25%, the first sub-layer is disposed away from the light absorption layer, the Nth sub-layer is disposed close to the light absorption layer, along the direction from the Nth sub-layer to the first sub-layer, the N sub-layers have a gradually increasing band gap and conduction band bottom energy level, and the absolute value of the difference in band gap between two adjacent sub-layers |ΔEg(HTL)| satisfies 0eV < |ΔEg(HTL)| ≦ 1.5eV, and the absolute value of the difference in conduction band bottom energy level between two adjacent sub-layers |ΔCBM(HTL)| satisfies 0eV < |ΔCBM(HTL)| ≦ 1.5eV. Method for manufacturing a solar cell

[0184] According to the fourth aspect of the embodiment of the present application, a method for manufacturing a solar cell is provided, and the method at least includes a method for forming a hole transport layer on the substrate surface of the first aspect of the embodiment of the present application.

[0185] The method for manufacturing a solar cell of the present application further includes steps of manufacturing a front electrode, manufacturing a light absorption layer, manufacturing an electron transport layer, and manufacturing a back electrode. Here, the film forming method of each of the above film layers is not specifically limited, and a known film forming method in the art may be adopted. For example, the above film layers can be grown by using any solution method, vacuum evaporation method, chemical vapor deposition method, sputtering method, etc.

[0186] In some embodiments, the method for manufacturing a solar cell of the present application includes steps of manufacturing a front electrode, forming a hole transport layer on the front electrode according to the method of the first aspect of the embodiment of the present application, forming a light absorption layer on the hole transport layer, forming an electron transport layer on the light absorption layer, and forming a back electrode on the electron transport layer.

[0187] In some embodiments, the method for manufacturing a solar cell of the present application includes manufacturing a front electrode, forming an electron transport layer on the front electrode, forming a light absorption layer on the electron transport layer, forming a hole transport layer on the light absorption layer according to the method of the first aspect of the embodiments of the present application, and forming a back electrode on the hole transport layer.

[0188] By using an X-ray photoelectron spectrometer (XPS) or an ultraviolet photoelectron spectrometer (UPS), the energy band distribution of each film layer can be obtained. Solar power generation assembly

[0189] According to the fifth aspect of the embodiments of the present application, a solar power generation assembly is provided, and the solar power generation assembly includes the solar cell of the third aspect of the embodiments of the present application, and the solar cell can be used as a power source of the solar power generation assembly. Example

[0190] The following examples describe the content disclosed in the present application more specifically. These examples are only used for illustrative purposes, and it is obvious to those skilled in the art that various modifications and changes can be made within the scope of the content disclosed in the present application. Unless otherwise specified, all parts, percentages, and ratio values reported in the following examples are based on mass. All reagents used in the examples can be purchased commercially or obtained by synthesis by general methods, and further treatment is not required and they can be used directly. And all instruments used in the examples can be purchased commercially. Example 1

[0191] Manufacture of ITO conductive glass electrode

[0192] Take ITO conductive glass with a specification of 2.0 cm × 2.0 cm, wash the surface of the ITO conductive glass twice with acetone and isopropyl alcohol in sequence, then immerse it in deionized water for ultrasonic treatment for 10 min, and further dry it in a blowing drying box.

[0193] Manufacture of Hole Transport Layer

[0194] Prepare four target materials according to the composition shown in Table 1, number them 1#, 2#, 3#, 4#,... respectively, attach and fix the four target materials to the cathode of the magnetron sputtering chamber in sequence, set the magnetron sputtering conditions for each target material according to Table 2, place the obtained ITO conductive glass on the anode of the magnetron sputtering chamber as the substrate, and the speed at which the substrate advances by transmission is 4.5 mm / s.

[0195] During magnetron sputtering, when the ITO conductive glass advances by transmission and passes through the 1# target material, a 1# sublayer having the same composition as the 1# target material is formed on the surface of the ITO conductive glass. As the ITO conductive glass advances by transmission, a 2# sublayer having the same composition as the 2# target material is continuously formed on the 1# sublayer, and so on by analogy.

[0196] After the magnetron sputtering is completed, a hole transport layer having four sublayers is obtained on the surface of the ITO conductive glass electrode, and the total thickness of the hole transport layer is 25 nm. At normal temperature and pressure, use an X-ray photoelectron spectrometer (XPS) of model Escalab 250Xi (manufactured by Thermo Scientific) to test the energy band distribution of each sublayer of the obtained hole transport layer, and the results are shown in Table 3.

Table 1

Table 2

Table 3

[0197] Manufacture of Light Absorbing Layer

[0198] After spin-coating a 1 mol / L MAPbI3 dimethylformamide solution on the obtained hole transport layer at a speed of 3000 rpm to 4500 rpm, it was transferred to a constant temperature hot stage, heated at 100 °C for 30 min, cooled to room temperature, and then an absorption layer was formed with a thickness of 500 nm.

[0199] Manufacture of electron transport layer

[0200] After spin-coating a PC 60 BM chlorobenzene solution with a concentration of 20 mg / L on the obtained absorption layer, it was transferred to a constant temperature hot stage, heated at 150 °C for 15 min, cooled to room temperature, and then an electron transport layer was formed with a thickness of 70 nm.

[0201] Manufacture of Ag electrode

[0202] The above-mentioned sample was placed in a vacuum coating machine, and under a vacuum condition of 5×10 -4 Pa, an Ag electrode was deposited on the surface of the obtained electron transport layer with a thickness of 80 nm.

[0203] The structure of the solar cell finally manufactured in Example 1 is ITO / NiO x Doped / MAPbI3 / PC 60 BM / Ag, and the schematic diagram of the energy level distribution of the solar cell manufactured in Example 1 is as shown in Figure 3.

[0204] The stability and consistency of the solar cell obtained by the method of this application are better, and the energy level structure of the hole transport layer in the solar cell can be easily adjusted by adjusting the specific composition of the target material or replacing the target material, which is advantageous for the energy level matching and optimization between the absorption layer and the hole transport layer.

[0205] Table 4 shows the test results of the short-circuit voltage Voc, short-circuit current density Jsc, fill factor, and energy conversion efficiency (Efficiency) of the solar cell manufactured in Example 1.

Table 4

[0206] The above content is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Those skilled in the art can easily conceive various equivalent changes and replacements within the technical scope disclosed in this application, and all of these changes and replacements belong to the protection scope of this application. Therefore, the protection scope of this application should conform to the protection scope of the claims.

Claims

1. A hole transport layer for a solar cell, comprising N continuous sub-layers, where N ≧ 3, and wherein, each sub-layer contains an inorganic hole transport material, one of the N sub-layers is a first sub-doped layer further containing a doping material, and the first sub-doped layer is the first sub-layer or the Nth sub-layer, and the doping material contains at least KI, the mass percentage content of KI in the first sub-doped layer is 20% or less, the N sub-layers have a bandgap that increases or decreases gradientally, and the absolute value of the difference in bandgap between two adjacent sub-layers is |ΔEg(HTL)|, and the absolute value of the difference in adjacent |ΔEg(HTL)| is greater than 0, a hole transport layer for a solar cell.

2. The hole transport layer according to Claim 1, wherein the inorganic hole transport materials of the sub-layers are the same as each other.

3. The dope material is NiO ｘ , CuO, Cu ２ O, Cu ２ S, CuI, CuSCN, CuGaO ２ , MgO, MnO, MnO ２ , Ag, Ag ２ O, Co, CoO, Li, Cs, Pb, In, Ga, Hg, Hg ２ O, Cr ２ O ３ , SnO, SnS, PbO or Pr ２ O ３ The hole transport layer according to claim 1, further comprising one or more of the above.

4. The hole transport layer according to Claim 1, wherein the first sub-doped layer contains MgO and KI, and the mass percentage content of each of MgO and KI in the first sub-doped layer is independently 20% or less.

5. The hole transport layer according to Claim 4, wherein based on the mass of the first sub-doped layer, the total mass percentage content of MgO and KI in the first sub-doped layer is 25% or less.

6. the N sub-layers have a bandgap that increases or decreases gradientally, and the absolute value of the difference in bandgap between two adjacent sub-layers |ΔEg(HTL)| satisfies 0 eV < |ΔEg(HTL)| ≦ 1.5 eV, and / or the N sub-layers have a conduction band bottom energy level that increases or decreases gradientally, and the absolute value of the difference in conduction band bottom energy level between two adjacent sub-layers |ΔCBM(HTL)| satisfies 0 eV < |ΔCBM(HTL)| ≦ 1.5 eV, the hole transport layer according to Claim 1.

7. The hole transport layer according to Claim 1, wherein the total thickness of the hole transport layer is 5 nm to 150 nm.

8. the N sub-layers further contain a second sub-doped layer, and the second sub-doped layer in the hole transport layer is The second sub-doping layer is NiO ｘ , CuO, Cu ２ O, Cu ２ S, CuI, CuSCN, CuGaO ２ , Ag, Ag ２ O, and the mass percentage content of each one or more of NiO ｘ , CuO, Cu ２ O, Cu ２ S, CuI, CuSCN, CuGaO ２ , Ag, Ag ２ O in the second sub-doping layer is independently 15% or less the second sub-doped layer contains one or two of MgO and KI, and the mass percentage content of each of one or two of MgO and KI in the second sub-doped layer is independently 20% or less, wherein the second sub-doping layer contains one or both of MnO and MnO ２ and the mass percentage content of each of one or both of MnO and MnO in the second sub-doping layer is independently 10% or less ２ ​ The second sub-doping layer contains one or both of Co and CoO, and the respective mass percentage content of one or both of Co and CoO in the second sub-doping layer is independently 8% or less, or wherein the second sub-doping layer contains one or more of Li, Cs, Pb, In, Ga, Hg, Hg ２ O, Cr ２ O ３ , SnO, SnS, PbO, Pr ２ O ３ and the mass percentage content of each of one or more of Li, Cs, Pb, In, Ga, Hg, Hg ２ O, Cr ２ O ３ , SnO, SnS, PbO, Pr ２ O ３ in the second sub-doping layer is independently 25% or less The hole transport layer according to claim 1, which satisfies at least one of the following.

9. A method for forming a hole transport layer for a solar cell according to claim 1 on a substrate surface, comprising providing M target materials containing an inorganic hole transport material; forming a hole transport layer including at least N continuous sub-layers on the substrate surface using magnetron sputtering, where M and N are integers, 3 ≤ N ≤ M, and one of the M target materials is a doped target material further containing a doping material, wherein the mass percentage content of KI in the doped target material is 20% or less.

10. The method according to claim 9, wherein the inorganic hole transport materials of the target materials are the same as each other.

11. The dope material is NiO ｘ , CuO, Cu ２ O, Cu ２ S, CuI, CuSCN, CuGaO ２ , MgO, MnO, MnO ２ , Ag, Ag ２ O, Co, CoO, Li, Cs, Pb, In, Ga, Hg, Hg ２ O, Cr ２ O ３ , SnO, SnS, PbO or Pr ２ O ３ The method according to claim 9, further comprising one or more of the above.

12. The method according to claim 9, wherein the doped target material is the first target material or the M-th target material.

13. The method according to claim 9, wherein the doped target material contains MgO and KI, and the respective mass percentage content of MgO and KI in the doped target material is independently 20% or less.

14. Based on the mass of the doped target material, the total mass percentage content of MgO and KI in the doped target material is 25% or less, according to the method of claim 13.

15. The method according to claim 9, wherein the hole transport layer has a gradient-changing energy level.

16. The hole transport layer has a gradient-changing bandgap, the M target materials have a gradient-changing bandgap, and the absolute value of the difference in bandgap between two adjacent target materials |ΔEg(TAG)| satisfies 0 eV ≤ |ΔEg(TAG)| ≤ 1.5 eV, and / or The hole transport layer has a gradient-changing conduction band bottom energy level, the M target materials have a gradient-changing conduction band bottom energy level, and the absolute value of the difference in conduction band bottom energy level between two adjacent target materials |ΔCBM(TAG)| satisfies 0 eV ≤ |ΔCBM(TAG)| ≤ 1.5 eV, according to the method of claim 15.

17. The method according to claim 9, wherein the substrate comprises a transparent electrode, a metal electrode, or a conductive carbon electrode.

18. The magnetron sputtering is The sputtering pressure is 2×10 －３ mbar to 8×10 －３ mbar, such that the gas flow rate is from 50 sccm to 250 sccm, the heating temperature is from 0 °C to 200 °C, the sputtering power is from 200 W to 13 KW, or the target-substrate distance is from 60 mm to 120 mm and satisfies at least one of the above, the method according to claim 9.

19. A solar cell comprising a hole transport layer for a solar cell according to claim 1.

20. A solar power generation assembly comprising the solar cell according to claim 19.

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