Solar cell and preparation method therefor, and photovoltaic assembly, system and electric apparatus

Abstract

The present application relates to a solar cell and a preparation method therefor, and a photovoltaic assembly, a system and an electric apparatus. The solar cell comprises a first electrode layer, a first hole transport layer, a perovskite light absorption layer and a second electrode layer, which are arranged in a stacked manner, wherein components of the first hole transport layer comprise P-type tin oxide. The solar cell has a relatively high photoelectric conversion efficiency.

Description

Solar cell and preparation method thereof, photovoltaic module, system and electrical device

[0001] Related applications

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on August 17, 2023, with application number 2023110388722, entitled “Solar cells and methods for their preparation, photovoltaic modules, systems and electrical devices”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of material technology, and in particular to a solar cell and a preparation method thereof, a photovoltaic module, a system and an electrical device. Background Art

[0004] Perovskite materials are organic-inorganic metal halides (ABX3) with an octahedral structure. The raw materials are abundant and can be widely synthesized. Perovskite materials offer numerous advantages, including high photoelectric absorption coefficients, long carrier diffusion lengths, and shallow defect levels, resulting in minimal photoelectric losses. Solar cells using perovskite materials as light-absorbing layers offer advantages such as reduced costs and increased efficiency, high low-light performance, and a wide range of applications, making them an excellent choice for the next generation of mass-produced photovoltaic cells.

[0005] However, the photoelectric conversion efficiency of perovskite solar cells still needs to be improved.

[0006] Summary of the Invention

[0007] Based on this, the present application aims to provide a solar cell and its preparation method, photovoltaic module, system and electrical device that can improve the photoelectric conversion efficiency.

[0008] A first aspect of the present application provides a solar cell comprising a stacked first electrode layer, a first hole transport layer, a perovskite light absorption layer, and a second electrode layer; a component of the first hole transport layer comprises P-type tin oxide.

[0009] Without wishing to be limited to any theory, the above-mentioned solar cell, by providing a first hole transport layer containing P-type tin oxide between the perovskite light absorption layer and the first electrode layer, is beneficial to improving the stability of the perovskite light absorption layer, while having better hole transport properties, thereby improving the photoelectric conversion efficiency of the solar cell device.

[0010] In any embodiment of the present application, the chemical formula of the P-type tin oxide is SnOx, 1≤x<2;

[0011] In any embodiment of the present application, 1≤x≤1.8.

[0012] In any embodiment of the present application, 1.2≤x≤1.8.

[0013] In any embodiment of the present application, 1.5≤x≤1.8.

[0014] In any embodiment of the present application, the components of the first hole transport layer further include a non-tin metal inorganic compound.

[0015] In any embodiment of the present application, the non-tin metal inorganic compound includes at least one of Al2O3, MoO3, Cu2O, CuI, CuSCN and CuO.

[0016] In any embodiment of the present application, the first hole transport layer includes a mixed layer formed by the non-tin metal inorganic compound and the P-type tin oxide.

[0017] In any embodiment of the present application, in the mixed layer, the mass fraction of the P-type tin oxide is greater than 0 and less than or equal to 50%.

[0018] In any embodiment of the present application, in the mixed layer, the mass fraction of the P-type tin oxide is 5% to 50%.

[0019] In any embodiment of the present application, in the mixed layer, the mass fraction of the P-type tin oxide is 20% to 50%.

[0020] In any embodiment of the present application, the first hole transport layer includes a P-type tin oxide layer and an intermediate layer, the intermediate layer includes the non-tin metal inorganic compound, and the P-type tin oxide layer is located between the intermediate layer and the perovskite light absorption layer.

[0021] In any embodiment of the present application, the thickness of the P-type tin oxide layer accounts for >0 and ≤50% of the total thickness of the first hole transport layer.

[0022] In any embodiment of the present application, the thickness of the P-type tin oxide layer accounts for 5% to 50% of the total thickness of the first hole transport layer.

[0023] In any embodiment of the present application, the thickness of the P-type tin oxide layer accounts for 20% to 50% of the total thickness of the first hole transport layer.

[0024] In any embodiment of the present application, the solar cell further includes a second hole transport layer, which is disposed between the first electrode layer and the first hole transport layer, and the second hole transport layer and the first hole transport layer are made of different materials.

[0025] In any embodiment of the present application, the solar cell satisfies at least one of the following conditions:

[0026] (1) The second hole transport layer includes at least one of PTAA, nickel oxide, Spiro-OMeTAD, WO3, PEDOT:PSS, poly-3-hexylthiophene, triphenylamine compounds and carbazole compounds;

[0027] (2) The thickness ratio of the second hole transport layer to the first hole transport layer is (0.8-10):1;

[0028] (3) The first electrode layer is a transparent electrode layer.

[0029] In any embodiment of the present application, the solar cell satisfies at least one of the following conditions:

[0030] The solar cell satisfies at least one of the following conditions:

[0031] (1) The second hole transport layer includes at least one of PTAA and nickel oxide;

[0032] (2) the thickness ratio of the second hole transport layer to the first hole transport layer is (2-10):1;

[0033] (3) The thickness of the first hole transport layer does not exceed 20 nm;

[0034] (4) The thickness of the second hole transport layer is 15 nm to 30 nm.

[0035] In any embodiment of the present application, the solar cell satisfies at least one of the following conditions:

[0036] The solar cell satisfies at least one of the following conditions:

[0037] (1) The thickness ratio of the second hole transport layer to the first hole transport layer is (2-6):1;

[0038] (2) The thickness of the first hole transport layer is 5 nm to 10 nm.

[0039] The second aspect of the present application provides a method for preparing the solar cell according to the first aspect of the present application, comprising the following steps:

[0040] The first electrode layer, the first hole transport layer, the perovskite light absorbing layer and the second electrode layer are stacked and formed.

[0041] In any embodiment of the present application, the preparation method further includes the step of forming a second hole transport layer between the first electrode layer and the first hole transport layer.

[0042] The third aspect of the present application provides a photovoltaic assembly, comprising the solar cell provided in the first aspect of the present application.

[0043] A fourth aspect of the present application provides a photovoltaic system, comprising the photovoltaic assembly provided by the third aspect of the present application.

[0044] The fifth aspect of the present application provides an electrical device comprising at least one selected from the solar cell provided in the first aspect of the present application and the photovoltaic module provided in the third aspect of the present application.

[0045] The details of one or more embodiments of the present application are set forth in the following drawings and description. Other features, objects, and advantages of the present application will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without any creative work.

[0047] FIG1 is a schematic diagram of a solar cell according to an embodiment of the present application;

[0048] FIG2 is a schematic diagram of a solar cell according to another embodiment of the present application;

[0049] FIG3 is a schematic diagram of an electrical device using a solar cell as a power source according to an embodiment of the present application.

[0050] Explanation of the accompanying symbols: 1. Solar cell; 11. Transparent electrode; 12. Second hole transport layer; 13. First hole transport layer; 14. Perovskite light absorption layer; 15. Electron transport layer; 16. Counter electrode layer; 2. Electric device. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] The following detailed description of the embodiments of the present application is appropriately referred to the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially identical structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0053] " range " disclosed in the present application is limited in the form of lower limit and upper limit, and given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of special range. The scope limited in this way can be to include end value or not include end value, and can be arbitrarily combined, that is, any lower limit can form a range with any upper limit combination. For example, if the scope of 60-120 and 80-110 is listed for specific parameters, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range value 1 and 2 are listed, and if the maximum range value 3,4 and 5 are listed, then the following range can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise specified, the numerical range " ab " represents the abbreviation of any real number combination between a and b, wherein a and b are all real numbers. For example, a numerical range of "0-5" indicates that all real numbers between "0-5" are listed herein, and "0-5" is simply an abbreviation for these numerical combinations. Furthermore, when a parameter is expressed as an integer ≥ 2, this is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0054] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution. Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0055] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), indicating that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0056] Unless otherwise specified, the terms "include" and "comprising" used in this application are open-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0057] Unless otherwise specified, the term "or" is used in this application to be inclusive. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: 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).

[0058] One embodiment of the present application provides a solar cell comprising a stacked first electrode layer, a first hole transport layer, a perovskite light absorbing layer, and a second electrode layer. The first hole transport layer comprises P-type tin oxide.

[0059] Without wishing to be limited to any theory, the above-mentioned solar cell is beneficial to improving the stability of the perovskite light absorption layer by setting a first hole transport layer containing P-type tin oxide between the perovskite light absorption layer and the first electrode layer, while having better hole transport properties, thereby improving the photoelectric conversion efficiency of the solar cell device.

[0060] Furthermore, conventional technologies use acidic PEDOT:PSS as the first hole transport layer, which can accelerate the degradation of perovskite materials when in contact with them, hindering the stability of solar cell devices and, consequently, their photoelectric conversion efficiency. Furthermore, PEDOT:PSS is an organic hole transport material, often prepared using a spin-coating process, which is unfavorable for the industrial production of large-area perovskite modules. Compared to PEDOT:PSS, the first hole transport layer of these solar cells contains p-type tin oxide, which not only improves the stability of the solar cell device and, consequently, its photoelectric conversion efficiency, but also allows for the use of processes such as physical vapor deposition and chemical vapor deposition, facilitating industrial production.

[0061] In some embodiments, the thickness of the perovskite light absorbing layer is 200 nm (nanometers) to 1000 nm. As an example, the thickness of the perovskite light absorbing layer is 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm; optionally, 400 nm to 500 nm.

[0062] The perovskite light absorbing layer can be prepared using methods commonly used in the art, including but not limited to sol-gel methods, coating, and multi-source co-evaporation. It is understood that coating methods include but are not limited to spin coating, slit coating, brush coating, wipe coating, doctor blade coating, screen coating, and spray coating. Furthermore, the perovskite light absorbing layer is a three-dimensional perovskite thin film.

[0063] In some embodiments, the perovskite light absorbing layer comprises a perovskite material. The general formula of the perovskite material is ABX3 or A2CDX6, where the A ion is a monovalent cation, the B ion is a divalent metal cation, the C ion is a monovalent metal cation, the D ion is a trivalent metal cation, and the X ion is a monovalent anion.

[0064] Optionally, the A ion includes at least one of an organic cation and a metal cation. More preferably, the organic cation includes at least one of an organic amine ion, a formamidinium group (FA), and an imidazole group; More preferably, the metal cation includes Li + 、Na + , K + , Rb + and Cs + Further, the organic amine ion includes at least one of methylamino (MA), ethylamino, propylamino, butylamino, pentylamino and hexylamino.

[0065] Optionally, the B ions include Pb 2+ 、Sn 2+ 、Be 2+ Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ 、Zn 2+ 、Ge 2+ 、Fe 2+ 、Co 2+ 、Cu 2+ and Ni 2+ More preferably, the B ions include Pb 2+ and Sn 2+ One or both of .

[0066] Optionally, the C ions include Cs + 、Ag + , K + and Ru + At least one of .

[0067] Optionally, the D ions include Bi 3+ 、Ni 3+ 、Fe 3+ and Cu 3+ At least one of;

[0068] Optionally, the X ions include F - 、Cl - Br - and I - At least one of; Optionally, the X ions include Cl - Br - and I - At least one of .

[0069] It is understood that the perovskite material in the above-mentioned perovskite light absorbing layer can be selected from at least one of CsFAPbX3, CsMAPbX3, CsFAMAPbX3, CsPbX3, MAPbX3, FAPbX3, CsFAPbSnX3, CsMAPbSnX3, CsFAMAPbSnX3, CsPbSnX3, MAPbSnX3, and FAPbSnX3. Further, as an example, the perovskite material in the above-mentioned perovskite light absorbing layer can be selected from at least one of CsFAPbI3, CsPbI3, and FAPbI3.

[0070] As an example, the general formula of perovskite materials is as follows: Cs a FA b MA c Pb d Sn e I f Br g , among them, a=0~0.05, b=0.8~0.95, c=0~0.1, d=0.5~1, e=0~0.5, f=2.0~3, g=0~1, a+b+c=1, d+e=1, f+g=3.

[0071] In some embodiments, the chemical formula of P-type tin oxide is SnOx, where 1≤x<2. Tin oxide of this chemical formula has oxygen vacancies and thus has good hole transport properties.

[0072] As an example, x may be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, or 1.9. Alternatively, 1≤x≤1.8; more preferably, 1.2≤x≤1.8; and even more preferably, 1.5≤x≤1.8.

[0073] It is understood that in some embodiments, the component of the first hole transport layer is P-type tin oxide, and no other hole transport material is added.

[0074] In some other embodiments, the components of the first hole transport layer also include non-tin metal inorganic compounds. It is understood that "non-tin metal inorganic compounds" refer to inorganic compounds formed by metals other than tin. Furthermore, the non-tin metal inorganic compounds include at least one of Al2O3, MoO3, Cu2O, CuI, CuSCN and CuO. In other words, the hole transport material of the first hole transport layer includes not only P-type tin oxide, but also non-tin metal inorganic compounds, such as at least one of Al2O3, MoO3, Cu2O, CuI, CuSCN and CuO.

[0075] Furthermore, in one example, the first hole transport layer includes a mixed layer of a non-tin metal inorganic compound and p-type tin oxide, such as a mixed layer of at least one of Al2O3, MoO3, Cu2O, CuI, CuSCN, and CuO, and p-type tin oxide. By regulating the composition and ratio of the mixed layer, the energy levels of the first hole transport layer and other functional layers are more closely matched, resulting in improved performance of the solar cell device.

[0076] Furthermore, in the mixed layer, the mass fraction of P-type tin oxide is greater than 0 and less than or equal to 50%, and optionally 5% to 50%, or 20% to 50%. As an example, in the mixed layer, the mass fraction of P-type tin oxide may be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%.

[0077] It is understood that the mixed layer can be prepared by adding multiple raw materials. For example, when using the atomic deposition method, two deposition raw materials can be used.

[0078] Furthermore, in another example, the first hole transport layer includes a p-type tin oxide layer and an intermediate layer. The intermediate layer includes a non-tin metal inorganic compound, such as at least one of Al2O3, MoO3, Cu2O, CuI, CuSCN, and CuO. The p-type tin oxide layer is located between the intermediate layer and the perovskite light absorption layer. The p-type tin oxide layer includes p-type tin oxide, or the material of the p-type tin oxide is p-type tin oxide.

[0079] As an example, the first hole transport layer includes a stacked P-type tin oxide layer and an intermediate layer, and the intermediate layer may be an aluminum oxide layer, a molybdenum oxide layer, or a cuprous oxide layer, or a layer formed of at least two of aluminum oxide, molybdenum oxide, and cuprous oxide.

[0080] Furthermore, the thickness of the p-type tin oxide layer accounts for >0 and ≤ 50% of the total thickness of the first hole transport layer; optionally, 5% to 50%, or 20% to 50%. As an example, the thickness of the p-type tin oxide layer may account for 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50% of the total thickness of the first hole transport layer.

[0081] It is understood that the stack of the p-type tin oxide layer and the intermediate layer can be prepared in two steps, and the preparation method of each layer can be specifically selected. It is understood that in some combination schemes, the first hole transport layer can contain both the above-mentioned mixed layer and the stack of the p-type tin oxide layer and the intermediate layer, and the relative positions of the three layers are not limited; optionally, the p-type tin oxide layer is in direct contact with the perovskite light absorption layer.

[0082] Furthermore, the preparation method of the first hole transport layer can be PVD (physical vapor deposition), CVD (chemical vapor deposition), ALD (atomic deposition technology), spin coating and other processes, preferably ALD (atomic deposition technology).

[0083] In some embodiments, the solar cell further comprises a second hole transport layer. The second hole transport layer is disposed between the first electrode layer and the first hole transport layer. The second hole transport layer and the first hole transport layer are made of different materials. By disposing a first hole transport layer made of a different material between the second hole transport layer and the perovskite light absorption layer, and the component of the first hole transport layer includes P-type tin oxide, the double-layer hole transport layer structure thus formed can improve the hole transport performance of the solar cell compared to the traditional single-layer hole transport layer, thereby improving the photoelectric conversion efficiency of the solar cell device.

[0084] In some embodiments, the material of the second hole transport layer includes but is not limited to at least one of the following materials and their derivatives: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), NiOx (nickel oxide), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), WO3, poly-3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), poly-3-hexylthiophene (P3HT), triphenylamine compounds and carbazole compounds, etc., which can transport holes and block electrons. One or more materials.

[0085] Among them, triphenylamine compounds include but are not limited to triphenylamine (H101) with a triptycene core and 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA). Carbazole compounds include but are not limited to N-(4-phenylamino)carbazole-spirobifluorene (CzPAF-SBF) and phosphate carbazole compounds. Furthermore, the second hole transport layer includes at least one of PTAA and a nickel oxide (NiOx) compound.

[0086] The hole transport materials that are currently widely used in inverse perovskite solar cells include NiOx and PTAA.

[0087] When NiOx is in direct contact with the perovskite light absorption layer, Ni in NiOx 3+ It will react with the organic cations of the perovskite material in the perovskite light absorbing layer to produce an oxidation-reduction reaction, causing the perovskite material to degrade, seriously limiting its service life. Therefore, when the material of the second hole transport layer is NiOx, a first hole transport layer containing P-type tin oxide is provided between the second hole transport layer and the perovskite light absorbing layer, thereby suppressing Ni 3+ The redox reaction between the organic cations and the perovskite material inhibits the degradation of the perovskite material, which is beneficial to improve the stability of the perovskite light absorption layer and solar cell devices and extend the service life of the solar cell devices.

[0088] PTAA's strong hydrophobicity results in extremely poor wettability of the perovskite precursor solution on its surface, thus affecting the crystallization of the perovskite material and hindering the preparation of high-performance solar cell devices. Therefore, when PTAA is used as the material for the second hole transport layer, by providing a first hole transport layer containing p-type tin oxide between the second hole transport layer and the perovskite light absorption layer, the wettability of PTAA with the perovskite precursor solution during the preparation process can be improved, which is beneficial for improving the crystallization quality of the resulting perovskite material and promoting the industrial production of solar cell devices.

[0089] In some embodiments, the thickness ratio of the second hole transport layer to the first hole transport layer is (0.8-10):1. As examples, the thickness ratio may be 0.8:1, 1:1, 2:1, 2.5:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. The thickness ratio of the second hole transport layer to the first hole transport layer may be (2-10):1, or more preferably (2-6):1.

[0090] In some embodiments, the thickness of the first hole transport layer does not exceed 10 nm, and may be 5 nm to 10 nm. As an example, the thickness of the first hole transport layer may be 2 nm, 3 nm, 5 nm, 7 nm, 8 nm, 9 nm, or 10 nm.

[0091] In some embodiments, the thickness of the second hole transport layer is 15 nm to 30 nm. As an example, the thickness of the second hole transport layer may be 15 nm, 20 nm, 25 nm, or 30 nm.

[0092] Optionally, the solar cell may further include an electron blocking layer between the first electrode layer and the second hole transport layer. The material of the electron blocking layer may be a known material.

[0093] In some embodiments, the solar cell may further include an electron transport layer, where the electron transport layer is located between the perovskite light absorbing layer and the second electrode layer.

[0094] As an example, the material of the electron transport layer can be, but is not limited to, at least one of the following materials and their derivatives: imide compounds, quinone compounds, fullerenes and their derivatives, methoxytriphenylamine-fluoroformamidine (OMeTPA-FA), [6,6]-phenyl C61 butyric acid methyl ester (PCBM), [6,6]-phenyl C71 butyric acid methyl ester (PC71BM), calcium titanate (CaTiO3), lithium fluoride (LiF), calcium fluoride (CaF2), poly (3,4-ethylenedioxythiophene): polystyrene sulfonic acid (PEDOT:PSS), poly 3-hexylthiophene (P3HT), triphenylamine with triptycene as the core (H101), 3,4-ethylenedioxythiophene-methoxytriphenylamine (EDOT-OMeTPA), N-(4-phenylamino)carbazole-spirobifluorene (CzPAF-SBF), polythiophene, metal oxides (metal elements are 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), and cuprous thiocyanate (CuSCN).

[0095] Optionally, the solar cell may further include a hole blocking layer between the second electrode layer and the electron transport layer.

[0096] The material of the hole blocking layer may include, but is not limited to, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline).

[0097] In a specific example, the electron transport layer adopts a PCBM layer, and the hole blocking layer adopts a BCP layer. The BCP layer serves as a passivation layer of the electron transport layer. The BCP molecular structure contains N atoms with lone pairs of electrons, which can effectively passivate the surface defects of the PCBM layer, promote the transfer and separation of charges at the interface, and help eliminate the current hysteresis of the battery device.

[0098] Understandably, in order to enable light to be effectively transmitted to the perovskite light absorption layer, at least one electrode in the solar cell is set as a transparent electrode, and the other is a counter electrode layer.

[0099] It can be understood that the solar cell includes a regular structure and a transverse structure in terms of structure. Optionally, one of the first electrode layer and the second electrode layer is a transparent electrode; the other can be a counter electrode layer.

[0100] The transparent electrode may be a transparent conductive metal oxide electrode. As an example, the material of the transparent electrode may be, for example, transparent conductive glass such as FTO, ITO, AZO, BZO, and IZO. It is understood that in addition to using glass as a substrate, the transparent electrode may also use a transparent flexible substrate. Specifically, the material of the transparent flexible substrate may be, for example, an organic polymer material, which may be a mixture of one or more of the following materials in different proportions: polyvinyl alcohol (PVA), polyester (PET), polyimide (PI), polyethylene naphthalate (PEN), and polydimethylsiloxane (PDMS).

[0101] The material of the counter electrode layer includes, but is not limited to, an organic material, an inorganic material, or a conductive material comprising a mixture of organic and inorganic materials in varying proportions. Furthermore, the counter electrode layer is a metal electrode. The metal conductive material of the counter electrode layer includes, but is not limited to, gold (Au), silver (Ag), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), bismuth (Bi), platinum (Pt), magnesium (Mg), or a mixture thereof.

[0102] For an inverted structure, as shown in FIG1 , a solar cell includes a transparent electrode 11 and a second hole transport layer 12, a first hole transport layer 13, a perovskite light absorbing layer 14, an electron transport layer 15, and a counter electrode layer 16, which are sequentially stacked on the transparent electrode 11. The first electrode layer is the transparent electrode 11, and the second electrode layer is the counter electrode layer 16.

[0103] As an example, as shown in FIG2 , the formal structure of a solar cell includes a transparent electrode 11 and an electron transport layer 15, a perovskite light absorption layer 14, a first hole transport layer 13, a second hole transport layer 12, and a counter electrode layer 16 stacked sequentially on the transparent electrode 11. The first electrode layer is the counter electrode layer, and the second electrode layer is the transparent electrode.

[0104] The present application also provides a method for preparing the above-mentioned solar cell, comprising the steps of forming a stacked first electrode layer, a second hole transport layer, a first hole transport layer, a perovskite light absorption layer and a second electrode layer.

[0105] In some embodiments, the preparation method includes the following steps S11 to S14.

[0106] S11, forming a second hole transport layer on the first electrode layer;

[0107] S12, forming a first hole transport layer on a surface of the second hole transport layer away from the first electrode layer;

[0108] S13, forming a perovskite light absorption layer on a surface of the first hole transport layer away from the second hole transport layer.

[0109] S14, forming a first electrode layer on a surface of the perovskite light absorption layer away from the first hole transport layer.

[0110] Specifically, as an example, the solar cell is in the trans type, and the preparation method thereof includes the following steps:

[0111] Step 1: Etch and clean the transparent electrode and dry it;

[0112] Step 2: sequentially preparing a second hole transport layer and a first hole transport layer on the transparent electrode;

[0113] Step 3: preparing a perovskite light absorbing layer on the first hole transport layer;

[0114] Step 4: preparing an electron transport layer on the perovskite light absorption layer;

[0115] Step 5: Prepare a counter electrode layer on the electron transport layer.

[0116] It is understandable that when the solar cell is formal, its preparation sequence is slightly different and can be slightly adjusted according to its structure.

[0117] In some examples, the method for preparing the above-mentioned perovskite light absorption layer includes the following steps: mixing material A, BX2 and a solvent to prepare a perovskite precursor solution; then coating the perovskite precursor solution on a corresponding substrate, annealing, and obtaining a perovskite light absorption layer.

[0118] The above-mentioned first electrode, second hole transport layer, first hole transport layer, electron transport layer and second electrode can be prepared by commonly used preparation methods in the art, including but not limited to solution method and solid deposition method. The solution method includes any one of spin coating, spray coating, blade coating and slit coating, and the solid deposition method includes any one of vacuum evaporation, sputtering deposition, plasma deposition and ion deposition.

[0119] One embodiment of the present application further provides a photovoltaic module, which includes the above-mentioned solar cell.

[0120] The solar cell has high light conversion efficiency and good stability, and can improve the efficiency of photovoltaic modules.

[0121] The photovoltaic module includes one or more of the aforementioned solar cells, which can be selected based on the specific application scenario. Furthermore, the photovoltaic module includes multiple solar cells, which are connected in series or parallel to form a cell. Furthermore, the photovoltaic module may also include a tandem cell, which includes one or more of the aforementioned solar cells. Tandem cells include, but are not limited to, crystalline silicon / perovskite tandem cells, all-perovskite tandem cells, and copper indium gallium selenide and other thin-film / perovskite tandem cells.

[0122] In some embodiments, the photovoltaic module further includes a photovoltaic glass layer, a bonding layer, and a back sheet.

[0123] Adhesive layers are provided on both surfaces of the cell, a back plate is provided on the surface of one of the adhesive layers away from the cell, and a photovoltaic glass layer is provided on the surface of the other adhesive layer away from the cell.

[0124] The photovoltaic glass layer and back panel are used to protect the solar cells, and have the functions of sealing, insulation and waterproofing; the bonding layer plays the role of bonding the photovoltaic glass layer and the battery cell, and bonding the back panel and the battery cell.

[0125] Optionally, the photovoltaic glass layer is made of tempered glass, the back panel is made of TPT (polyvinyl fluoride) or TPE (thermoplastic elastomer), and the adhesive layer is made of EVA (polyethylene-polyvinyl acetate copolymer).

[0126] Furthermore, the photovoltaic module further includes a junction box and an outer frame.

[0127] The junction box is used to protect the power generation system of the entire photovoltaic module. It is equivalent to a current transfer station. When a battery cell short-circuits, the junction box will automatically disconnect the short-circuited battery string.

[0128] The outer frame can support and protect the entire photovoltaic module. The frame can be made of aluminum alloy, which has excellent strength and corrosion resistance.

[0129] Furthermore, silicone is used to bond and seal the connection between the frame and other parts of the photovoltaic module. Photovoltaic modules can convert solar energy into electrical energy, which can be stored in batteries or used to drive loads.

[0130] In some embodiments, the photovoltaic component is a solar panel.

[0131] One embodiment of the present application further provides a photovoltaic system, comprising the above-mentioned photovoltaic module.

[0132] The photovoltaic system utilizes the photovoltaic effect of the solar cells in the above photovoltaic modules to directly convert solar radiation energy into electrical energy with high efficiency; further, the above photovoltaic system is a photovoltaic power generation system.

[0133] Photovoltaic modules are the core part of photovoltaic power generation systems. The above photovoltaic system includes one or more photovoltaic modules, which can be selected according to the specific application scenario; further, when the above photovoltaic system includes multiple photovoltaic modules, the multiple photovoltaic modules form a photovoltaic array.

[0134] The above photovoltaic system can be an independent photovoltaic power generation system or a grid-connected photovoltaic power generation system.

[0135] An independent photovoltaic power generation system consists of a photovoltaic array, a battery pack, a charge controller, a power electronic converter (inverter), and a load. Its operating principle is that solar radiation energy is first converted into electrical energy by the photovoltaic array, then converted by the power electronic converter to power the load. Meanwhile, excess electrical energy is stored as chemical energy in an energy storage device after passing through the charge controller. In this way, when sunlight is insufficient, the energy stored in the battery can be converted into 220V, 50Hz AC electricity after passing through the power electronic inverter, filtering, and power frequency transformer to supply the AC load.

[0136] A grid-connected photovoltaic power generation system consists of a photovoltaic array, a high-frequency DC / DC boost circuit, a power electronic converter (inverter), and system monitoring. Its operating principle is that solar radiation energy is converted by the photovoltaic array, then converted to high-voltage DC through high-frequency DC conversion. This is then inverted by a power electronic inverter and output to the grid as a sinusoidal AC current with a frequency consistent with the grid voltage.

[0137] The above two photovoltaic power generation systems have their own characteristics and can be selected according to specific application scenarios.

[0138] One embodiment of the present application provides an electrical device, including the above-mentioned solar cell or the above-mentioned photovoltaic module.

[0139] In some embodiments, the solar cell or photovoltaic module can be used as a power source for an electrical device or as an energy storage unit for an electrical device.

[0140] Furthermore, the above-mentioned electrical devices may include mobile devices, such as mobile phones, laptop computers, etc., electric vehicles, electric trains, ships and satellites, but are not limited thereto.

[0141] Figure 3 shows an example of an electric device 2. The electric device 2 is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.

[0142] In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, the application will be further described in detail below with reference to the embodiments and drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0143] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0144] 1. Device Preparation

[0145] Example 1

[0146] A method for preparing a solar cell device with an inverted structure is as follows:

[0147] 1) Preparation of FTO conductive glass electrode: Specifications: 2.0*2.0cm 2 The FTO glass was removed by laser etching at both ends to remove 0.35 cm of FTO to expose the glass substrate; the etched FTO conductive glass was ultrasonically cleaned several times with water, acetone, and isopropyl alcohol, and then dried with nitrogen for later use;

[0148] 2) Preparation of the second hole transport layer: FTO was treated with UV ozone, and then nickel oxide with a thickness of approximately 20 nm was magnetron sputtered. The second hole transport layer was annealed at 300°C for 60 minutes.

[0149] 3) Preparation of a First Hole Transport Layer: A SnOx layer (x = 1.76, as determined by XPS analysis of the film; the value of x is controlled by controlling the oxygen flow rate during the atomic deposition process, similarly below) with a thickness of approximately 5 nm was deposited on the surface of the second hole transport layer to obtain the first hole transport layer;

[0150] 4) Preparation of perovskite light absorbing layer: The perovskite light absorbing layer was prepared using a one-step method. Specifically, the perovskite precursor solution was spin-coated on the prepared first hole transport layer at a speed of 4000 rpm for 20-40 seconds. 300-600 μL of anti-solvent was added dropwise around 10 seconds after the start of spin coating. The film was then placed on a hot plate and annealed at 120°C for 60 minutes to obtain a perovskite light absorbing layer with a thickness of 500 nm. The composition of the perovskite material in the perovskite light absorbing layer was Cs 0.05 FA 0.95 PbI3;

[0151] 5) Preparation of electron transport layer: Place the device with perovskite light absorbing layer prepared in step 4) into the evaporation apparatus, and wait until the evaporation vacuum reaches 5*10 -4 Pa below, a 30 nm thick electron transport layer (C60 layer) and a 5 nm thick passivation layer (or hole blocking layer, made of BCP) were sequentially deposited at a rate of 0.05 A / s;

[0152] 6) Preparation of metal counter electrode: Place the film with electron transport layer prepared in step 5) into the evaporation apparatus and wait for the evaporation vacuum to reach 5*10 -4 Pa, and a Cu back electrode with a thickness of 80 nm was evaporated at a rate of 0.1 A / s.

[0153] Example 2

[0154] Except for step 2), the other steps are the same as those in Example 1. Step 2) is specifically as follows.

[0155] 2) Preparation of a Second Hole Transport Layer: FTO was treated with UV-ozone, and then a 2 mg / mL PTAA organic hole transport layer was spin-coated at 5000 rpm / s, followed by annealing on a 100°C hot plate for 10 minutes to obtain a second hole transport layer with a thickness of approximately 30 nm.

[0156] Examples 3 to 5

[0157] It is basically the same as Example 1, except that by controlling the oxygen flow rate during the atomic deposition method in step 3) of the first hole transport layer, the x of SnOx in the first hole transport layer (SnOx layer) is regulated to be different, as shown in Table 1.

[0158] Examples 6 to 8

[0159] The method is basically the same as Example 1, except that the thickness of the first hole transport layer (SnOx layer) is regulated by controlling the time of the atomic deposition method in step 3) of the first hole transport layer, as shown in Table 1.

[0160] Example 9

[0161] It is basically the same as Example 1, except that the second hole transport layer is omitted and only the first hole transport layer is included, as shown in Table 1.

[0162] Examples 10 to 15

[0163] The method is basically the same as Example 1, except that, on the basis of keeping the thickness of the first hole transport layer unchanged, the raw materials used in the atomic deposition process of the first hole transport layer in step 3) are controlled to be different, so that the deposited first hole transport layer is controlled to be a mixed layer; the SnOx mass content in the mixed layer is controlled by controlling the ratio of the raw materials, as shown in Table 2.

[0164] Examples 16 to 21

[0165] It is basically the same as Example 1, except that after the P-type SnOx layer is deposited in step 3), an intermediate layer is formed on the basis of the P-type SnOx layer by atomic deposition; and a subsequent perovskite light absorbing layer is formed on the intermediate layer, as shown in Table 3.

[0166] Comparative Example 1

[0167] The process is basically the same as Example 1, except that the type of the first hole transport layer deposited in step 3) is different, as follows:

[0168] 3) Preparation of the first hole transport layer: Aluminum oxide with a thickness of about 5 nm was prepared on the surface of the second hole transport layer by an atomic deposition method to obtain the first hole transport layer.

[0169] Comparative Example 2

[0170] The process is basically the same as Example 1, except that the type of the first hole transport layer deposited in step 3) is different, as follows:

[0171] 3) Preparation of the first hole transport layer: Cuprous oxide with a thickness of about 5 nm was prepared on the surface of the second hole transport layer by an atomic deposition method to obtain the first hole transport layer.

[0172] Comparative Example 3

[0173] The method is basically the same as Example 2, except that the type of the first hole transport layer deposited in step 3) is different, as follows:

[0174] 3) Preparation of the first hole transport layer: Aluminum oxide with a thickness of about 5 nm was prepared on the surface of the second hole transport layer by an atomic deposition method to obtain the first hole transport layer.

[0175] Comparative Example 4

[0176] The method is basically the same as Example 2, except that the type of the first hole transport layer deposited in step 3) is different, as follows:

[0177] 3) Preparation of the first hole transport layer: Molybdenum oxide with a thickness of about 5 nm was prepared on the surface of the second hole transport layer by an atomic deposition method to obtain the first hole transport layer.

[0178] 2. Performance Testing

[0179] Photovoltaic conversion efficiency of perovskite solar cells

[0180] Using Keithley 2400SMU, AM 1.5G solar irradiation at 100mW / cm 2 The battery performance was tested under a light source, and the photoelectric conversion efficiency was calculated as follows: PCE = Pout / Popt = Voc×Jsc×(Vmpp×Jmpp) / (Voc×Jsc) = Voc×Jsc×FF

[0181] Among them, Pout, Popt, Vmpp, Jmpp, Voc and Jsc are the battery operating output power, incident light power, battery maximum power point voltage, battery maximum power point current, open circuit voltage and short circuit current respectively.

[0182] According to the above process, four perovskite solar cells obtained in each of the above embodiments and comparative examples were tested respectively, and the obtained results were averaged. For specific results, please refer to Tables 1 to 3.

[0183] Table 1

[0184] Table 2

[0185] Table 3

[0186] It can be seen from Tables 1 to 3 that the photoelectric conversion performance of the solar cells prepared in Examples 1 to 20 is higher than that of the comparative examples.

[0187] In Table 1, the only difference between Examples 1 and 2 is that the material type of the second hole transport layer is different, and the solar cells prepared therefrom all have good photoelectric conversion performance; the only difference between Examples 1 and 3 to 5 is that the x of SnOx in the first hole transport layer (SnOx layer) is different, and x is further 1.2 to 1.8, and the solar cells prepared therefrom have good photoelectric conversion performance. The only difference between Examples 1 and 6 to 8 is that the thickness of the first hole transport layer is different, and the thickness is further 5nm to 10nm, and the solar cells prepared therefrom have good photoelectric conversion performance. Example 9 contains only the first hole transport layer and does not contain the second hole transport layer, and the solar cell prepared therefrom also has good photoelectric conversion performance.

[0188] As shown in Table 2, Examples 10-15 differ from Example 1 in that, while the thickness of the first hole transport layer remains unchanged, a mixed material is used to form the first hole transport layer. Compared to Example 1, the solar cells produced in Examples 10-15 exhibit better photoelectric conversion performance. Furthermore, by controlling the SnOx content in the first hole transport layer to 20% to 50% by mass, the resulting solar cells exhibit even better photoelectric conversion performance.

[0189] As can be seen from Table 3, the difference between Examples 16 to 21 and Example 1 is that, while the thickness of the SnOx layer remains unchanged, another material is used to form an intermediate layer in the SnOx layer, and the SnOx layer and the intermediate layer together serve as the first hole transport layer; compared with Example 1, the solar cells prepared in Examples 16 to 21 have better photoelectric conversion performance; further, by controlling the proportion of the SnOx layer thickness in the first hole transport layer to 20% to 50%, the resulting solar cells have better photoelectric conversion performance.

[0190] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0191] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A solar cell comprising a first electrode layer, a first hole transport layer, a perovskite light absorption layer and a second electrode layer which are stacked; the first hole transport layer comprises P-type tin oxide.

2. The solar cell according to claim 1, wherein: The chemical formula of the P-type tin oxide is SnOx, 1≤x<2.

3. The solar cell according to claim 2, wherein: 1≤x≤1.8。 4. The solar cell according to claim 3, wherein: 1.2≤x≤1.8。 5. The solar cell according to claim 4, wherein: 1.5≤x≤1.8。 6. The solar cell according to any one of claims 1 to 5, wherein: The first hole transport layer further comprises a non-tin metal inorganic compound.

7. The solar cell according to claim 6, wherein: The non-tin metal inorganic compound includes at least one of Al2O3, MoO3, Cu2O, CuI, CuSCN and CuO.

8. The solar cell according to claim 6 or 7, wherein: The first hole transport layer includes a mixed layer formed by the non-tin metal inorganic compound and the P-type tin oxide.

9. The solar cell according to claim 8, wherein: In the mixed layer, the mass fraction of the P-type tin oxide is greater than 0 and less than or equal to 50%.

10. The solar cell according to claim 9, wherein: In the mixed layer, the mass fraction of the P-type tin oxide is 5% to 50%.

11. The solar cell according to claim 10, wherein: In the mixed layer, the mass fraction of the P-type tin oxide is 20% to 50%.

12. The solar cell according to claim 6 or 7, wherein: The first hole transport layer includes a P-type tin oxide layer and an intermediate layer, the intermediate layer includes the non-tin metal inorganic compound, and the P-type tin oxide layer is located between the intermediate layer and the perovskite light absorption layer.

13. The solar cell according to claim 12, wherein: In the total thickness of the first hole transport layer, the thickness of the P-type tin oxide layer accounts for >0 and ≤50%.

14. The solar cell according to claim 13, wherein: The thickness of the P-type tin oxide layer accounts for 5% to 50% of the total thickness of the first hole transport layer.

15. The solar cell according to claim 14, wherein: The thickness of the P-type tin oxide layer accounts for 20% to 50% of the total thickness of the first hole transport layer.

16. The solar cell according to any one of claims 1 to 15, wherein: The solar cell further includes a second hole transport layer, which is disposed between the first electrode layer and the first hole transport layer, and the second hole transport layer and the first hole transport layer are made of different materials.

17. The solar cell according to claim 16, wherein: The solar cell satisfies at least one of the following conditions: (1) The second hole transport layer includes at least one of PTAA, nickel oxide, Spiro-OMeTAD, WO3, PEDOT:PSS, poly-3-hexylthiophene, triphenylamine compounds and carbazole compounds; (2) The thickness ratio of the second hole transport layer to the first hole transport layer is (0.8-10):1; (3) The first electrode layer is a transparent electrode layer.

18. The solar cell according to claim 17, wherein: The solar cell satisfies at least one of the following conditions: (1) The second hole transport layer includes at least one of PTAA and nickel oxide; (2) a thickness ratio of the second hole transport layer to the first hole transport layer is (2-10):1; (3) The thickness of the first hole transport layer does not exceed 20 nm; (4) The thickness of the second hole transport layer is 15 nm to 30 nm.

19. The solar cell according to claim 18, wherein: The solar cell satisfies at least one of the following conditions: (1) The thickness ratio of the second hole transport layer to the first hole transport layer is (2-6):1; (2) The thickness of the first hole transport layer is 5 nm to 10 nm.

20. A method for preparing a solar cell according to any one of claims 1 to 19, comprising the following steps: The first electrode layer, the first hole transport layer, the perovskite light absorption layer and the second electrode layer are stacked and formed.

21. The method for preparing a solar cell according to claim 20, wherein: The preparation method further includes the step of forming a second hole transport layer between the first electrode layer and the first hole transport layer.

22. A photovoltaic module comprising the solar cell according to any one of claims 1 to 19.

23. A photovoltaic system comprising the photovoltaic module according to claim 22.

24. An electrical device comprising at least one selected from the solar cell according to any one of claims 1 to 19 and the photovoltaic module according to claim 22.

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