A solar cell based on an organic acceptor-perovskite heterojunction light-absorbing layer

Abstract

The present invention discloses a solar cell based on an organic acceptor-perovskite heterojunction light-absorbing layer, comprising: a transparent electrode layer, a first transport layer, a perovskite light-absorbing layer, a second transport layer and a metal electrode layer stacked sequentially from bottom to top; wherein, when the solar cell is positive, the first transport layer is an organic acceptor light-absorbing layer used as an electron transport layer, and the second transport layer is a hole transport layer; when the solar cell is in reverse, the first transport layer is a hole transport layer, and the second transport layer is an organic acceptor light-absorbing layer used as an electron transport layer. The present invention uses organic acceptors and perovskite materials together as light-absorbing layers to increase the light absorption range and light absorption intensity of the light-absorbing layer, avoids the problems of band-hopping light absorption of pure organic photovoltaic devices and narrow light absorption range of pure inorganic photovoltaic devices, and improves solar spectrum utilization and photoelectric conversion efficiency. And using an organic acceptor light-absorbing layer as an electron transport layer can reduce process steps and reduce costs without damaging the electron extraction capability.

Description

Technical Field

[0001] The present invention belongs to the field of solar cells, and in particular relates to a solar cell based on an organic acceptor-perovskite heterojunction light-absorbing layer, a preparation method of a positive solar cell, and a preparation method of an inverted solar cell. Background Art

[0002] The energy crisis is a major issue facing society today. Developing new power generation technologies based primarily on clean energy sources, such as solar energy, is an effective way to balance energy supply and environmental protection. New photovoltaic materials, represented by organometallic halide perovskites, have garnered widespread attention and achieved significant development in recent years. In recent years, novel perovskite thin-film solar cells have attracted increasing attention and research due to their tunable band gap (1.2-2.3 eV), high light absorption coefficient, high energy conversion efficiency (reaching 25.5%), and low manufacturing cost.

[0003] Since 2009, the energy conversion efficiency of perovskite solar cells has increased from 3.8% to 25.5%. The fastest increase was from 3.8% to 22.1% between 2009 and 2016. However, between 2016 and 2021, the efficiency only increased by 3.4%. The limited absorption spectrum is a key reason for the slowdown in perovskite solar cell efficiency gains in recent years. Addressing this issue has become a hot research topic in the solar cell field. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the present invention provides a solar cell based on an organic acceptor-perovskite heterojunction light-absorbing layer, a method for preparing a positive-type solar cell, and a method for preparing an inverted-type solar cell. The technical problems to be solved by the present invention are achieved through the following technical solutions:

[0005] In a first aspect, an embodiment of the present invention provides a solar cell based on an organic acceptor-perovskite heterojunction light absorbing layer, comprising:

[0006] A transparent electrode layer, a first transport layer, a perovskite light-absorbing layer, a second transport layer and a metal electrode layer are stacked in sequence from bottom to top; wherein, when the solar cell is positive, the first transport layer is an organic acceptor light-absorbing layer used as an electron transport layer, and the second transport layer is a hole transport layer; when the solar cell is inverse, the first transport layer is a hole transport layer, and the second transport layer is an organic acceptor light-absorbing layer used as an electron transport layer.

[0007] In one embodiment of the present invention, the transparent electrode layer comprises a bottom transparent substrate and a surface thin film electrode;

[0008] The material of the bottom transparent substrate in the transparent electrode layer includes:

[0009] Glass, double-polished sapphire and polyethylene terephthalate (PET) flexible materials.

[0010] In one embodiment of the present invention, the material of the surface thin film electrode in the transparent electrode layer includes:

[0011] Indium tin oxide ITO, fluorine-doped tin oxide FTO and aluminum-doped zinc oxide AZO.

[0012] In one embodiment of the present invention, the transparent electrode layer comprises:

[0013] FTO conductive glass.

[0014] In one embodiment of the present invention, the material of the organic acceptor light-absorbing layer includes:

[0015] Synthetic materials Y6, BTP-4Cl and (6,6)-phenyl-C71-butyric acid methyl ester PC71BM.

[0016] In one embodiment of the present invention, the material of the perovskite light absorbing layer includes:

[0017] Cesium lead bromide CsPbBr3, cesium lead iodide bromide CsPbIBr2 and methylamine iodide perovskite MAPbI3.

[0018] In one embodiment of the present invention, the material of the hole transport layer includes:

[0019] p-type semiconductor material.

[0020] In one embodiment of the present invention, the material of the metal electrode layer includes:

[0021] Gold and silver.

[0022] In a second aspect, an embodiment of the present invention provides a method for preparing a positive solar cell, comprising:

[0023] preparing a transparent electrode layer;

[0024] An organic acceptor light-absorbing layer is prepared on the upper surface of the transparent electrode layer by a solution spin coating method; wherein the organic acceptor light-absorbing layer is used as an electron transport layer;

[0025] Prepare a perovskite light-absorbing layer on the upper surface of the organic acceptor light-absorbing layer by solution spin coating;

[0026] A hole transport layer is prepared on the upper surface of the perovskite light absorbing layer by using a solution spin coating method;

[0027] A conductive film is grown on the upper surface of the hole transport layer by using a thermal evaporation or magnetron sputtering method as a metal electrode layer.

[0028] In a third aspect, an embodiment of the present invention provides a method for preparing an inverted solar cell, comprising:

[0029] preparing a transparent electrode layer;

[0030] A hole transport layer is prepared on the upper surface of the transparent electrode layer by using a solution spin coating method;

[0031] A perovskite light absorbing layer is prepared on the upper surface of the hole transport layer by a solution spin coating method;

[0032] An organic acceptor light-absorbing layer is prepared on the upper surface of the perovskite light-absorbing layer by a solution spin coating method; wherein the organic acceptor light-absorbing layer serves as an electron transport layer;

[0033] A conductive film is grown on the upper surface of the organic acceptor light-absorbing layer by using a thermal evaporation or magnetron sputtering method as a metal electrode layer.

[0034] The solar cell based on the organic acceptor-perovskite heterojunction light-absorbing layer provided in the embodiment of the present invention. Since the organic acceptor material and the perovskite material are used together as the light-absorbing layer, the light-absorbing range and light-absorbing intensity of the light-absorbing layer are increased, which can avoid the band-hopping light-absorbing problem of pure organic photovoltaic devices and the narrow light-absorbing range of pure inorganic photovoltaic devices, and can improve the utilization rate of the solar spectrum and the photoelectric conversion efficiency. In addition, the embodiment of the present invention uses the organic acceptor light-absorbing layer as the electron transport layer, which can reduce the process steps and reduce costs without damaging the electron extraction capability. The solar cell based on the organic acceptor-perovskite heterojunction light-absorbing layer provided in the embodiment of the present invention can be used in the fields of high-efficiency, low-cost photovoltaic power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A schematic structural diagram of a solar cell based on an organic acceptor-perovskite heterojunction light-absorbing layer provided by an embodiment of the present invention;

[0036] Figure 2(a) and Figure 2(b) are Figure 1 Schematic diagram of the structure of positive-type solar cells and inverted-type solar cells in the provided solar cells based on organic acceptor-perovskite heterojunction light-absorbing layer;

[0037] Figure 3 A schematic flow chart of a method for preparing a positive solar cell provided by an embodiment of the present invention;

[0038] FIG4(a) and FIG4(b) are schematic structural diagrams of two specific positive-type solar cells provided in an embodiment of the present invention;

[0039] Figure 5 A schematic flow chart of a method for preparing an inverted solar cell provided by an embodiment of the present invention;

[0040] FIG6(a) and FIG6(b) are schematic structural diagrams of two specific inverted solar cells provided by embodiments of the present invention. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] In a first aspect, an embodiment of the present invention provides a solar cell based on an organic acceptor-perovskite heterojunction light absorbing layer. Figure 1 , Figure 1 A schematic structural diagram of a solar cell based on an organic acceptor-perovskite heterojunction light absorbing layer provided in an embodiment of the present invention; Figure 1 As shown, the solar cell may include:

[0043] A transparent electrode layer, a first transport layer, a perovskite light-absorbing layer, a second transport layer and a metal electrode layer are stacked in sequence from bottom to top; wherein, when the solar cell is positive, the first transport layer is an organic acceptor light-absorbing layer used as an electron transport layer, and the second transport layer is a hole transport layer; when the solar cell is inverse, the first transport layer is a hole transport layer, and the second transport layer is an organic acceptor light-absorbing layer used as an electron transport layer.

[0044] exist Figure 1 In the figure, the transparent electrode layer, the first transmission layer, the perovskite light absorption layer, the second transmission layer, and the metal electrode layer are represented by numbers 1 to 5, respectively. The text in the dotted box is used as a graphic annotation.

[0045] It will be understood by those skilled in the art that the embodiments of the present invention are based on Figure 1 The structure shown actually provides a positive solar cell and an inverted solar cell. For the sake of intuitive understanding, the structure of the positive solar cell is shown in FIG2(a), and the structure of the inverted solar cell is shown in FIG2(b).

[0046] In FIG2( a ), the positive-type solar cell includes a transparent electrode layer, an organic acceptor light-absorbing layer (serving as an electron transport layer), a perovskite light-absorbing layer, a hole transport layer, and a metal electrode layer stacked sequentially from bottom to top.

[0047] In FIG2( b ), the inverted solar cell includes a transparent electrode layer, a hole transport layer, a perovskite light-absorbing layer, an organic acceptor light-absorbing layer (serving as an electron transport layer), and a metal electrode layer stacked sequentially from bottom to top.

[0048] The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer in the embodiment of the present invention is described in detail below.

[0049] 1) Regarding the transparent electrode layer:

[0050] The transparent electrode layer includes a bottom transparent substrate and a surface thin film electrode.

[0051] The transparent electrode layer has high transmittance and low resistance, and its underlying transparent substrate is typically made of a high-transmittance material. For example, in one embodiment, the transparent electrode layer's underlying transparent substrate may be made of glass, double-polished sapphire, or a flexible polyethylene terephthalate (PET) material. In practice, any of these materials may be selected as needed.

[0052] In an optional embodiment, the material of the surface thin film electrode in the transparent electrode layer includes:

[0053] Indium tin oxide ITO, fluorine-doped tin oxide FTO and aluminum-doped zinc oxide AZO.

[0054] In practice, any one of the materials can be selected as needed.

[0055] In an optional embodiment, which is more commonly used, the transparent electrode layer includes:

[0056] FTO conductive glass.

[0057] 2) Regarding the organic acceptor light-absorbing layer:

[0058] In an optional embodiment, the material of the organic acceptor light-absorbing layer includes:

[0059] Synthetic materials Y6, BTP-4Cl and (6,6)-phenyl-C71-butyric acid methyl ester PC71BM.

[0060] Among them, the organic material systems corresponding to Y6 and BTP-4Cl belong to the non-fullerene system, and the organic material system corresponding to PC71BM belongs to the fullerene system. Y6 and BTP-4Cl are new materials synthesized experimentally and have no Chinese names yet.

[0061] In practice, any one of the materials can be selected as needed.

[0062] The organic acceptor light-absorbing layer can also be prepared using other high-efficiency organic photovoltaic acceptor materials other than the above three.

[0063] 3) Regarding the perovskite light-absorbing layer:

[0064] In an optional embodiment, the material of the perovskite light absorbing layer includes:

[0065] Cesium lead bromide CsPbBr3, cesium lead iodide bromide CsPbIBr2 and methylamine iodide perovskite MAPbI3.

[0066] In practice, any one of the materials can be selected as needed.

[0067] 4) Regarding the hole transport layer:

[0068] In an optional embodiment, the material of the hole transport layer includes:

[0069] p-type semiconductor material.

[0070] Specifically, the p-type semiconductor material may include:

[0071] Organic materials such as 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD); 3-hexylthiophene (P3HT); polyethylenedioxythiophene-poly(styrenesulfonate) (PEDOT:PSS); and nickel oxide (NiO x ); molybdenum trioxide (MoO3) and other inorganic materials.

[0072] In practice, any one of the materials can be selected as needed.

[0073] 5) Regarding the metal electrode layer:

[0074] In an optional embodiment, the material of the metal electrode layer includes:

[0075] Gold Au and silver Ag.

[0076] Of course, the metal electrode layer in the embodiment of the present invention may also be made of other precious metal materials.

[0077] The inventors have discovered that using organic acceptor materials and perovskite materials to form a heterojunction light-absorbing layer can broaden the spectral range and improve the energy conversion efficiency of solar cells. For example, the perovskite material MAPbI3 absorbs light in the wavelength range of 350nm-750nm, while the organic acceptor material BTP-4Cl absorbs light in the wavelength range of 600nm-940nm. Combining MAPbI3 and BTP-4Cl into a heterojunction light-absorbing layer can significantly increase the solar cell's light absorption range compared to single-junction perovskite solar cells in the prior art, improving the utilization efficiency of the entire solar spectrum and, in turn, increasing the solar cell's energy conversion efficiency. Furthermore, using an organic acceptor layer as an electron transport layer does not compromise electron extraction capability and is fully compatible with the process of single-junction perovskite solar cells. It can also eliminate the need for an existing electron transport layer, simplifying the process and reducing costs.

[0078] The solar cell based on the organic acceptor-perovskite heterojunction light-absorbing layer provided in the embodiment of the present invention. Since the organic acceptor material and the perovskite material are used together as the light-absorbing layer, the light-absorbing range and light-absorbing intensity of the light-absorbing layer are increased, which can avoid the band-hopping light-absorbing problem of pure organic photovoltaic devices and the narrow light-absorbing range of pure inorganic photovoltaic devices, and can improve the utilization rate of the solar spectrum and the photoelectric conversion efficiency. In addition, the embodiment of the present invention uses the organic acceptor light-absorbing layer as the electron transport layer, which can reduce the process steps and reduce costs without damaging the electron extraction capability. The solar cell based on the organic acceptor-perovskite heterojunction light-absorbing layer provided in the embodiment of the present invention can be used in the fields of high-efficiency, low-cost photovoltaic power generation.

[0079] In the second aspect, the present invention provides a method for preparing a positive solar cell. Figure 3 , Figure 3 The present invention provides a schematic flow diagram of a method for preparing a positive solar cell. The method comprises the following steps:

[0080] S301, preparing a transparent electrode layer.

[0081] The transparent electrode layer includes a bottom transparent substrate and a surface thin film electrode. In an optional embodiment, the material of the bottom transparent substrate in the transparent electrode layer includes:

[0082] Glass, double-polished sapphire and PET flexible materials.

[0083] In practice, any one of the materials can be selected as needed.

[0084] In an optional embodiment, the material of the surface thin film electrode in the transparent electrode layer includes:

[0085] ITO, FTO and AZO.

[0086] In practice, any one of the materials can be selected as needed.

[0087] The transparent electrode layer can be obtained by depositing a surface thin film electrode on the bottom transparent substrate. The specific process belongs to the existing technology and will not be described in detail here.

[0088] In one optional implementation, the transparent electrode layer may be FTO conductive glass.

[0089] S302 , preparing an organic acceptor light-absorbing layer on the upper surface of the transparent electrode layer by solution spin coating; wherein the organic acceptor light-absorbing layer is used as an electron transport layer.

[0090] A layer of organic receptor material can be deposited on the upper surface of the transparent electrode layer by a solution spin coating method as an organic receptor light-absorbing layer.

[0091] For the specific implementation of the solution spin coating method, please refer to the relevant existing technology and will not be described in detail here.

[0092] In an optional embodiment, the material of the organic acceptor light-absorbing layer includes:

[0093] Y6, BTP-4Cl and PC71BM.

[0094] In practice, any one of the materials can be selected as needed.

[0095] The organic acceptor light-absorbing layer can also be prepared using other high-efficiency organic photovoltaic acceptor materials other than the above three.

[0096] S303, preparing a perovskite light-absorbing layer on the upper surface of the organic acceptor light-absorbing layer by solution spin coating.

[0097] A layer of perovskite material can be deposited on the upper surface of the organic acceptor light-absorbing layer by a solution spin coating method as a perovskite light-absorbing layer.

[0098] In an optional embodiment, the material of the perovskite light absorbing layer includes:

[0099] CsPbBr3, CsPbIBr2 and MAPbI3.

[0100] In practice, any one of the materials can be selected as needed.

[0101] S304, preparing a hole transport layer on the upper surface of the perovskite light absorbing layer by solution spin coating.

[0102] A layer of hole transport layer material can be deposited on the upper surface of the perovskite light absorbing layer by a solution spin coating method, and then crystallized to form a thin film.

[0103] In an optional embodiment, the material of the hole transport layer includes:

[0104] p-type semiconductor material.

[0105] Specifically, the p-type semiconductor material may include: organic materials such as spiro-OMeTAD, P3HT, PEDOT:PSS, and NiO x , MoO3 and other inorganic materials.

[0106] In practice, any one of the materials can be selected as needed.

[0107] S305 , growing a conductive film as a metal electrode layer on the upper surface of the hole transport layer by using a thermal evaporation or magnetron sputtering method.

[0108] For the specific implementation of thermal evaporation or magnetron sputtering methods, please refer to the relevant existing technologies and will not be described in detail here.

[0109] In the embodiment of the present invention, the material of the metal electrode layer is selected from noble metals. For example, in an optional embodiment, the material of the metal electrode layer includes:

[0110] Gold and silver.

[0111] Hereinafter, the embodiments of the present invention provide two specific positive-type solar cells and illustrate the corresponding preparation methods and processes.

[0112] ①The first positive solar cell:

[0113] For the positive-type solar cell based on the organic acceptor-perovskite heterojunction light absorption layer shown in Figure 2(a), the specific materials selected for each layer are shown in Table 1. The specific structure is shown in Figure 4(a).

[0114] Table 1

[0115] Layer number Layer Name Material 5 Metal electrode layer Au(Ag) 4 hole transport layer Spiro-OMeTAD 3 Perovskite light-absorbing layer <![CDATA[MAPbI3]]> 2 Organic acceptor light-absorbing layer (used as electron transport layer) BTP-4Cl 1 Transparent electrode layer FTO conductive glass

[0116] Among them, the absorption band of BTP-4Cl is 600nm-940nm; the absorption band of MAPbI3 is 350nm-750nm.

[0117] The following are the specific steps of the preparation process.

[0118] S301-1, prepare a FTO conductive glass transparent electrode layer.

[0119] Specifically, a transparent FTO conductive glass was obtained, and ultrasonically cleaned with a detergent, deionized water, acetone, and anhydrous ethanol for 15 minutes respectively, and then air-dried with a nitrogen flow to obtain a prepared FTO conductive glass transparent electrode layer.

[0120] S302-1, preparing a BTP-4Cl organic acceptor light-absorbing layer on the upper surface of the FTO conductive glass transparent electrode layer by solution spin coating.

[0121] Among them, the BTP-4Cl organic acceptor light-absorbing layer is used as the electron transport layer.

[0122] Specifically, 10 mg of BTP-4Cl was dissolved in 1 mL of chloroform to prepare a BTP-Cl solution as the organic receptor precursor solution. The FTO conductive glass transparent electrode layer was then UV-ozone cleaned (i.e., UV-ozone treated) for 15 minutes. The BTP-Cl solution was then spin-coated on the treated FTO conductive glass transparent electrode layer at a rotation speed of 3000 rpm for 45 seconds. The solution was then annealed at 100°C for 10 minutes.

[0123] Among them, rpm is the abbreviation of Revolutions Per Minute, which is revolutions per minute and is the unit of rotation speed.

[0124] S303-1, preparing a MAPbI3 perovskite light-absorbing layer on the upper surface of the BTP-4Cl organic acceptor light-absorbing layer by solution spin coating.

[0125] Specifically, 1.6 mmol / mL of lead iodide (PbI2) and 1.6 mmol / mL of methylamine iodide (CH3NH3I) were dissolved in a mixed solvent of γ-butyrolactone (GBL) and dimethyl sulfoxide (DMSO) (volume ratio of 1:1) to prepare a MAPbI3 solution as a perovskite precursor solution. The MAPbI3 solution was spin-coated on the surface of the BTP-4Cl organic acceptor light-absorbing layer at two speeds: 1000 rpm (spin time 15 seconds) and 3500 rpm (spin time 35 seconds). The coating was rinsed with 350 μL of chlorobenzene in the last 10 seconds of the spin-coating process, followed by annealing at 100°C for 10 minutes.

[0126] S304-1, spin-coating a Spiro-OMeTAD solution on the upper surface of the MAPbI3 perovskite light-absorbing layer to prepare a Spiro-OMeTAD hole transport layer.

[0127] Specifically, the prepared Spiro-OMeTAD solution was spin-coated on the upper surface of the MAPbI3 perovskite light-absorbing layer at a speed of 1000 rpm (spinning time 5 s) + 4000 rpm (spinning time 40 s), dried in the shade and allowed to stand for two minutes to oxidize for one day.

[0128] S305-1, growing an Au (Ag) metal electrode layer on the upper surface of the Spiro-OMeTAD hole transport layer by a thermal evaporation method.

[0129] The growth conditions of the metal electrode layer are as follows: pressure 1E-4Pa; power 100W; and thickness of the Au (Ag) metal film is 100nm.

[0130] ②The second type of positive solar cell:

[0131] For the inverted solar cell based on the organic acceptor-perovskite heterojunction light absorption layer shown in FIG2(b), the specific materials selected for each layer are shown in Table 2. The specific structure is shown in FIG4(b).

[0132] Table 2

[0133] Layer number Layer Name Material 5 Metal electrode layer Au(Ag) 4 hole transport layer Spiro-OMeTAD 3 Perovskite light-absorbing layer <![CDATA[CsPbIBr2]]> 2 Organic acceptor light-absorbing layer (used as electron transport layer) Y6 1 Transparent electrode layer FTO conductive glass

[0134] Among them, the Y6 absorption band is 600nm-930nm, and the CsPbIBr2 absorption band is 350nm-600nm.

[0135] The following are the specific steps of the preparation process.

[0136] S301-2, prepare a FTO conductive glass transparent electrode layer.

[0137] Specifically, a transparent FTO conductive glass was obtained, and ultrasonically cleaned with a detergent, deionized water, acetone, and anhydrous ethanol for 15 minutes respectively, and then air-dried with a nitrogen flow to obtain a prepared FTO conductive glass transparent electrode layer.

[0138] S302-2, preparing a Y6 organic acceptor light-absorbing layer on the upper surface of the FTO conductive glass transparent electrode layer by solution spin coating.

[0139] Among them, the Y6 organic acceptor light-absorbing layer is used as the electron transport layer.

[0140] Specifically, 9.6 mg of Y6 was dissolved in 1 mL of chloroform to prepare a Y6 solution as an organic receptor precursor solution. The FTO conductive glass transparent electrode layer was then UV-ozone cleaned (i.e., UV-ozone treated) for 15 minutes. The Y6 solution was then spin-coated on the treated FTO conductive glass transparent electrode layer at a rotation speed of 3000 rpm for 45 seconds. The solution was then annealed at 100°C for 10 minutes.

[0141] S303-2, preparing a CsPbIBr2 perovskite light-absorbing layer on the upper surface of the Y6 organic acceptor light-absorbing layer by solution spin coating.

[0142] Specifically, 367 mg of lead bromide (PbBr2) and 260 mg of cesium iodide (CsI) were dissolved in 1 mL of DMSO and stirred for 2 hours to form a clear CsPbIBr2 solution as a perovskite precursor solution. The CsPbIBr2 solution was spin-coated on the FTO conductive glass transparent electrode layer at two speeds: 1500 rpm (spin time 30 seconds) and 5000 rpm (spin time 60 seconds). The mixture was then annealed at 280°C for 10 minutes.

[0143] S304-2, spin-coating a Spiro-OMeTAD solution on the upper surface of the CsPbIBr2 perovskite light-absorbing layer to prepare a Spiro-OMeTAD hole transport layer.

[0144] Specifically, the prepared Spiro-OMeTAD solution was spin-coated on the upper surface of the CsPbIBr2 perovskite light-absorbing layer at a speed of 1000 rpm (spinning time 5 s) + 4000 rpm (spinning time 40 s), dried in the shade and allowed to stand for two minutes to oxidize for one day.

[0145] S305-2, growing an Au (Ag) metal electrode layer on the upper surface of the Spiro-OMeTAD hole transport layer by a thermal evaporation method.

[0146] The growth conditions of the metal electrode layer are as follows: pressure 1E-4Pa; power 100W; and thickness of the Au (Ag) metal film is 100nm.

[0147] In a third aspect, the present invention provides a method for preparing an inverted solar cell. Figure 5 , Figure 5 The present invention provides a schematic flow diagram of a method for preparing an inverted solar cell. The method comprises the following steps:

[0148] S501, preparing a transparent electrode layer.

[0149] The transparent electrode layer includes a bottom transparent substrate and a surface thin film electrode. In an optional embodiment, the material of the bottom transparent substrate in the transparent electrode layer includes:

[0150] Glass, double-polished sapphire and PET flexible materials.

[0151] In practice, any one of the materials can be selected as needed.

[0152] In an optional embodiment, the material of the surface thin film electrode in the transparent electrode layer includes:

[0153] ITO, FTO and AZO.

[0154] In practice, any one of the materials can be selected as needed.

[0155] The transparent electrode layer can be obtained by depositing a surface thin film electrode on the bottom transparent substrate. The specific process belongs to the existing technology and will not be described in detail here.

[0156] In one optional implementation, the transparent electrode layer may be FTO conductive glass.

[0157] S502 , preparing a hole transport layer on the upper surface of the transparent electrode layer by solution spin coating.

[0158] A layer of hole transport layer material can be deposited on the upper surface of the transparent electrode layer by a solution spin coating method, and then crystallized to form a thin film.

[0159] For the specific implementation of the solution spin coating method, please refer to the relevant existing technology and will not be described in detail here.

[0160] In an optional embodiment, the material of the hole transport layer includes:

[0161] p-type semiconductor material.

[0162] Specifically, the p-type semiconductor material may include: organic materials such as spiro-OMeTAD, P3HT, PEDOT:PSS, and NiO x , MoO3 and other inorganic materials.

[0163] In practice, any one of the materials can be selected as needed.

[0164] S503, preparing a perovskite light absorbing layer on the upper surface of the hole transport layer by solution spin coating.

[0165] A layer of perovskite material can be deposited on the upper surface of the hole transport layer by a solution spin coating method as a perovskite light absorbing layer.

[0166] In an optional embodiment, the material of the perovskite light absorbing layer includes:

[0167] CsPbBr3, CsPbIBr2 and MAPbI3.

[0168] In practice, any one of the materials can be selected as needed.

[0169] S504, preparing an organic acceptor light-absorbing layer on the upper surface of the perovskite light-absorbing layer by solution spin coating; wherein the organic acceptor light-absorbing layer is used as an electron transport layer.

[0170] A layer of organic acceptor material can be deposited on the upper surface of the perovskite light-absorbing layer by a solution spin coating method as an organic acceptor light-absorbing layer.

[0171] In an optional embodiment, the material of the organic acceptor light-absorbing layer includes:

[0172] Y6, BTP-4Cl and PC71BM.

[0173] In practice, any one of the materials can be selected as needed.

[0174] The organic acceptor light-absorbing layer can also be prepared using other high-efficiency organic photovoltaic acceptor materials other than the above three.

[0175] S505 , growing a conductive film as a metal electrode layer on the upper surface of the organic acceptor light-absorbing layer by using a thermal evaporation or magnetron sputtering method.

[0176] For the specific implementation of thermal evaporation or magnetron sputtering methods, please refer to the relevant existing technologies and will not be described in detail here.

[0177] In an embodiment of the present invention, the material of the metal electrode layer is selected from noble metals. For example, in an optional embodiment, the material of the metal electrode layer includes:

[0178] Gold and silver.

[0179] Hereinafter, the embodiments of the present invention provide two specific inverted solar cells and illustrate the corresponding preparation methods and processes.

[0180] ①The first inverted solar cell:

[0181] For the inverted solar cell based on the organic acceptor-perovskite heterojunction light absorption layer shown in Figure 2(b), the specific materials used for each layer are shown in Table 3. The specific structure is shown in Figure 6(a).

[0182] Table 3

[0183] Layer number Layer Name Material 5 Metal electrode layer Au(Ag) 4 Organic acceptor light-absorbing layer (used as electron transport layer) BTP-4Cl 3 Perovskite light-absorbing layer <![CDATA[MAPbI3]]> 2 hole transport layer <![CDATA[NiO x ]]> 1 Transparent electrode layer FTO conductive glass

[0184] Among them, the BTP-4Cl absorption band is 600nm-940nm, and the MAPbI3 absorption band is 350nm-750nm.

[0185] The following are the specific steps of the preparation process.

[0186] S501-1, prepare a FTO conductive glass transparent electrode layer.

[0187] Specifically, a transparent FTO conductive glass was obtained, and ultrasonically cleaned with a detergent, deionized water, acetone, and anhydrous ethanol for 15 minutes respectively, and then air-dried with a nitrogen flow to obtain a prepared FTO conductive glass transparent electrode layer.

[0188] S502-1, spin coating NiO on the upper surface of the FTO conductive glass transparent electrode layer x Solution, preparation of NiO x Hole transport layer.

[0189] Specifically, the FTO conductive glass transparent electrode layer was subjected to UV ozone cleaning (i.e. UV-ozone treatment) for 15 minutes, and the NiO prepared in advance was x The solution was spin-coated on the FTO conductive glass transparent electrode layer at a rotation rate of 3000 rpm for 30 seconds, and then annealed at 250° C. for 45 minutes to crystallize into a film.

[0190] S503-1, in the NiO x The MAPbI3 perovskite light-absorbing layer was prepared on the upper surface of the hole transport layer by solution spin coating.

[0191] Specifically, 1.6 mmol / mL of PbI2 and 1.6 mmol / mL of CH3NH3I were dissolved in a mixed solvent of GBL:DMSO (volume ratio of 1:1) to prepare a MAPbI3 solution as a perovskite precursor solution. x The MAPbI3 solution was spin-coated on the upper surface of the hole transport layer at two rotation speeds, where the MAPbI3 rotation speeds were 1000 rpm (spin time 15 s) and 3500 rpm (spin time 35 s), and rinsed with 350 μL of chlorobenzene in the last 10 s of the spin coating process, and then annealed at 100 °C for 10 minutes.

[0192] S504-1, preparing a BTP-4Cl organic acceptor light-absorbing layer on the upper surface of the MAPbI3 perovskite light-absorbing layer by solution spin coating.

[0193] Among them, the BTP-4Cl organic acceptor light-absorbing layer is used as the electron transport layer.

[0194] Specifically, 10 mg of BTP-4Cl was dissolved in 1 mL of chloroform solution. The BTP-4Cl solution was spin-coated on the surface of the MAPbI3 perovskite light-absorbing layer at a rotation speed of 3000 rpm (spin time 45 seconds), and then annealed at 100°C for 10 minutes.

[0195] S505-1, growing an Au (Ag) metal electrode layer on the upper surface of the BTP-4Cl organic acceptor light-absorbing layer by a thermal evaporation method.

[0196] The growth conditions of the metal electrode layer are as follows: pressure 1E-4Pa; power 100W; and thickness of the Au (Ag) metal film is 100nm.

[0197] ②The second type of inverted solar cell:

[0198] For the inverted solar cell based on the organic acceptor-perovskite heterojunction light absorption layer shown in Figure 2(b), the specific materials selected for each layer are shown in Table 3. The specific structure is shown in Figure 6(b).

[0199] Table 4

[0200] Layer number Layer Name Material 5 Metal electrode layer Au(Ag) 4 Organic acceptor light-absorbing layer (used as electron transport layer) Y6 3 Perovskite light-absorbing layer <![CDATA[CsPbIBr2]]> 2 hole transport layer <![CDATA[NiO x ]]> 1 Transparent electrode layer FTO conductive glass

[0201] Among them, the Y6 absorption band is 600nm-930nm, and the CsPbIBr2 absorption band is 350nm-600nm.

[0202] The following are the specific steps of the preparation process.

[0203] S501-2, preparing a FTO conductive glass transparent electrode layer.

[0204] Specifically, a transparent FTO conductive glass was obtained, and ultrasonically cleaned with a detergent, deionized water, acetone, and anhydrous ethanol for 15 minutes respectively, and then air-dried with a nitrogen flow to obtain a prepared FTO conductive glass transparent electrode layer.

[0205] S502-2, spin coating NiO on the upper surface of the FTO conductive glass transparent electrode layer x Solution, preparation of NiO x Hole transport layer.

[0206] Specifically, the FTO conductive glass transparent electrode layer was subjected to UV ozone cleaning (i.e. UV-ozone treatment) for 15 minutes, and the NiO prepared in advance was x The solution was spin-coated on the FTO conductive glass transparent electrode layer at a rotation rate of 3000 rpm for 30 seconds, and then annealed at 250° C. for 45 minutes to crystallize into a film.

[0207] S503-2, in the NiO x The CsPbIBr2 perovskite light absorbing layer was prepared on the upper surface of the hole transport layer by solution spin coating.

[0208] Specifically, 367 mg of PbBr2 and 260 mg of CsI were dissolved in 1 mL of DMSO and then stirred for 2 hours to form a clear CsPbIBr2 solution as a perovskite precursor solution. x The upper surface of the hole transport layer was spin-coated with the CsPbIBr2 solution at two rotation speeds, wherein the CsPbIBr2 rotation speeds were 1500 rpm (rotation time 30 s) and 5000 rpm (rotation time 60 s), and then annealed at 280°C for 10 minutes.

[0209] S504-2, preparing a Y6 organic acceptor light-absorbing layer on the upper surface of the CsPbIBr2 perovskite light-absorbing layer by solution spin coating.

[0210] Among them, the Y6 organic acceptor light-absorbing layer is used as the electron transport layer.

[0211] Specifically, 9.6 mg of Y6 was dissolved in 1 mL of chloroform solution. The Y6 solution was spin-coated on the CsPbIBr2 perovskite light-absorbing layer at a rotation speed of 3000 rpm for 45 seconds. The film was then annealed at 100°C for 10 minutes.

[0212] S505-2, growing an Au (Ag) metal electrode layer on the upper surface of the Y6 organic acceptor light-absorbing layer by a thermal evaporation method.

[0213] Where Au is gold and Ag is silver. The growth conditions of the metal electrode layer are: pressure 1E-4Pa; power 100W; Au (Ag) metal film thickness 100nm.

[0214] It should be noted that Figures 2, 4 and 6 are schematic diagrams of the distribution of layers from bottom to top. For simplicity, the layer numbers are not shown in the above figures.

[0215] The embodiments of the present invention provide an overall preparation process for positive-type and inverted-type solar cells based on an organic acceptor-perovskite heterojunction light-absorbing layer. Taking into account the absorption bands of organic acceptor materials and perovskite materials, suitable materials are selected to specifically propose two positive-type solar cells based on an organic acceptor-perovskite heterojunction light-absorbing layer, and two inverted-type solar cells based on an organic acceptor-perovskite heterojunction light-absorbing layer. Since both the organic acceptor material and the perovskite material are used as the light-absorbing layer, the absorption range and absorption intensity of the light-absorbing layer are increased, which can avoid the band-hopping absorption of pure organic photovoltaic devices and the narrow absorption range of pure inorganic photovoltaic devices, thereby improving the utilization rate of the solar spectrum and the photoelectric conversion efficiency. Furthermore, the embodiments of the present invention utilize an organic acceptor light-absorbing layer as an electron transport layer, which can reduce process steps and reduce costs without damaging the electron extraction capability. Any solar cell based on an organic acceptor-perovskite heterojunction light-absorbing layer provided by the embodiments of the present invention can be used in fields such as high-efficiency and low-cost photovoltaic power generation.

[0216] The above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A solar cell based on an organic acceptor-perovskite heterojunction light absorbing layer, characterized in that: include: A transparent electrode layer, a first transport layer, a perovskite light-absorbing layer, a second transport layer and a metal electrode layer are stacked in sequence from bottom to top; wherein, when the solar cell is positive, the first transport layer is an organic acceptor light-absorbing layer used as an electron transport layer, and the second transport layer is a hole transport layer; when the solar cell is inverse, the first transport layer is a hole transport layer, and the second transport layer is an organic acceptor light-absorbing layer used as an electron transport layer; wherein, for positive and inverse types, the organic acceptor light-absorbing layer and the perovskite light-absorbing layer are prepared by solution spin coating; the organic acceptor light-absorbing layer and the perovskite light-absorbing layer form a heterojunction light-absorbing layer to broaden the spectral range and improve the energy conversion efficiency of the solar cell; the combination of the heterojunction light-absorbing layer includes: the organic acceptor light-absorbing layer is a synthetic material Y6, and the perovskite light-absorbing layer is cesium lead iodine bromine CsPbIBr2, or the organic acceptor light-absorbing layer is BTP-4Cl, and the perovskite light-absorbing layer is methylamine iodide perovskite MAPbI3.

2. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 1, characterized in that: The transparent electrode layer includes a bottom transparent substrate and a surface thin film electrode; The material of the bottom transparent substrate in the transparent electrode layer includes: Glass, double-polished sapphire and polyethylene terephthalate (PET) flexible materials.

3. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 2, characterized in that: The material of the surface thin film electrode in the transparent electrode layer includes: Indium tin oxide ITO, fluorine-doped tin oxide FTO and aluminum-doped zinc oxide AZO.

4. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 3, characterized in that: The transparent electrode layer comprises: FTO conductive glass.

5. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 1, characterized in that: The material of the organic acceptor light-absorbing layer also includes: Phenyl-C71-butyric acid methyl ester PC71BM.

6. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 1, characterized in that: The material of the perovskite light absorbing layer also includes: Cesium lead bromine CsPbBr3.

7. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 1, characterized in that: The materials of the hole transport layer include: p-type semiconductor material.

8. The solar cell based on the organic acceptor-perovskite heterojunction light absorbing layer according to claim 1, characterized in that: The materials of the metal electrode layer include: Gold and silver.

9. A method for preparing a positive solar cell, characterized in that: include: preparing a transparent electrode layer; An organic acceptor light-absorbing layer is prepared on the upper surface of the transparent electrode layer by a solution spin coating method; wherein the organic acceptor light-absorbing layer is used as an electron transport layer; Prepare a perovskite light-absorbing layer on the upper surface of the organic acceptor light-absorbing layer by solution spin coating; A hole transport layer is prepared on the upper surface of the perovskite light absorbing layer by using a solution spin coating method; Growing a conductive film as a metal electrode layer on the upper surface of the hole transport layer by thermal evaporation or magnetron sputtering; The organic acceptor light-absorbing layer and the perovskite light-absorbing layer form a heterojunction light-absorbing layer to broaden the spectral range and improve the energy conversion efficiency of the solar cell. The combination of the heterojunction light-absorbing layer includes: positive combination form 1: the organic acceptor light-absorbing layer is BTP-4Cl, and the perovskite light-absorbing layer is methylamine iodide perovskite MAPbI3; and positive combination form 2: the organic acceptor light-absorbing layer is synthetic material Y6, and the perovskite light-absorbing layer is cesium lead iodine bromine CsPbIBr2; In positive combination form 1, when spin-coating BTP-Cl, the BTP-Cl rotation speed is 3000 rpm and the rotation time is 45 seconds; annealing is carried out at 100°C for 10 minutes; when spin-coating MAPbI3, the MAPbI3 solution is spin-coated on the upper surface of the BTP-4Cl organic acceptor light-absorbing layer at two speed levels, wherein the MAPbI3 rotation speed is 1000 rpm for 15 seconds in the first level and 3500 rpm for 35 seconds in the second level, and finally annealing is carried out at 100°C for 10 minutes after rinsing with chlorobenzene. In the positive combination form 2, when spin-coating the synthetic material Y6, the Y6 rotation speed is 3000 rpm, and the rotation time is 45 seconds; then it is annealed at 100°C for 10 minutes; when spin-coating CsPbIBr2, the CsPbIBr2 solution is spin-coated on the transparent electrode layer with two-level rotation speeds, wherein the CsPbIBr2 rotation speed is 1500 rpm for the first level, the rotation time is 30 seconds, and the second level is 5000 rpm for the second level, the rotation time is 60 seconds, and then it is annealed at 280°C for 10 minutes.

10. A method for preparing an inverted solar cell, characterized in that: include: preparing a transparent electrode layer; A hole transport layer is prepared on the upper surface of the transparent electrode layer by using a solution spin coating method; A perovskite light absorbing layer is prepared on the upper surface of the hole transport layer by a solution spin coating method; An organic acceptor light-absorbing layer is prepared on the upper surface of the perovskite light-absorbing layer by a solution spin coating method; wherein the organic acceptor light-absorbing layer is used as an electron transport layer; growing a conductive film as a metal electrode layer on the upper surface of the organic acceptor light-absorbing layer by thermal evaporation or magnetron sputtering; The organic acceptor light-absorbing layer and the perovskite light-absorbing layer form a heterojunction light-absorbing layer to broaden the spectral range and improve the energy conversion efficiency of the solar cell. The combination of the heterojunction light-absorbing layer includes: inverse combination form 1: the perovskite light-absorbing layer is methylamine iodide perovskite MAPbI3, and the organic acceptor light-absorbing layer is BTP-4Cl; and inverse combination form 2: the perovskite light-absorbing layer is cesium lead iodine bromine CsPbIBr2, and the organic acceptor light-absorbing layer is synthetic material Y6. In the inverse combination form 1, when spin-coating MAPbI3, a MAPbI3 solution is spin-coated on the upper surface of the hole transport layer at two speed levels, wherein the MAPbI3 speed is 1000 rpm for 15 seconds in the first level and 3500 rpm for 35 seconds in the second level, and finally annealed at 100°C for 10 minutes after rinsing with chlorobenzene. When spin-coating BTP-4Cl, a BTP-4Cl solution is spin-coated on the upper surface of the MAPbI3 perovskite light absorbing layer at a speed of 3000 rpm for 45 seconds, and then annealed at 100°C for 10 minutes. In the inverse combination form 2, when spin-coating CsPbIBr2, the CsPbIBr2 solution is spin-coated on the upper surface of the hole transport layer with two-level rotation speeds, wherein the CsPbIBr2 rotation speed is 1500 rpm for the first level, the rotation time is 30s, and the second level is 5000 rpm for the second level, the rotation time is 60s, and then annealed at 280°C for 10 minutes; when spin-coating the synthetic material Y6, the Y6 solution is spin-coated on the CsPbIBr2 perovskite light absorbing layer, wherein the rotation speed of Y6 is 3000 rpm for the second level, the rotation time is 45s, and then annealed at 100°C for 10 minutes.

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