Solar cell and preparation method thereof

Abstract

The invention provides a solar cell and a preparation method thereof. The perovskite solar cell provided by the invention comprises a transparent conductive substrate, a first carrier transport layer, a perovskite active layer, a photo-oxygen protection layer, a second carrier transport layer and a metal electrode layer which are stacked in sequence, and the material of the photo-oxygen protection layer comprises a compound shown in a general formula (I). The compound shown in the general formula (I) is introduced into the photo-oxygen protection layer, and the photo-oxygen protection layer is introduced into the perovskite solar cell, so that on one hand, the hydrophobicity of the perovskite solar cell can be improved, the nucleation crystallization of a perovskite cubic phase (alpha phase) is promoted, and the generation of a non-perovskite phase (delta phase) is inhibited, thereby improving the purity of the alpha phase in the perovskite active layer; and on the other hand, the effect of passivating defects can be exerted, so that the stability, durability and photoelectric conversion efficiency of the perovskite solar cell can be improved. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a solar cell and a method for preparing the same. Background Art

[0002] Perovskite solar cells belong to the third generation of solar cells, which have the characteristics of high photoelectric conversion efficiency (PCE), low cost, excellent optical performance and simple preparation. In addition, stacked structure cells have been widely recognized as an effective way to improve cell efficiency. The basic principle is to regard the solar spectrum as different parts, and use solar cell materials with bandgap widths matching different spectral bands to make a stacked cell structure to maximize the conversion of light energy into electrical energy. In particular, due to the high light absorption and bandgap adjustability of perovskite materials, the rapid development of perovskite / crystalline silicon stacked solar cells in recent years is obvious to all, and its conversion rate has increased from less than 23% in 2017 to 29.1% in 2020.

[0003] However, both perovskite solar cells and perovskite / crystalline silicon stacked solar cells have the problem of photo-oxygen-induced degradation of perovskite under photo-oxygen exposure. The most common method to solve the above problem is physical means to isolate oxygen, such as packaging and improving device structure. However, due to its specific device structure, physical means lead to the complexity of its device preparation process, which leads to its cost increase; and although packaging is widely used and can largely prevent oxygen from diffusing into perovskite devices, a small amount of oxygen may still exist in the gap between the glass substrate and the cover glass, or slow oxygen leakage may occur during device operation due to aging of the encapsulation glue. At present, there are relatively few studies on solving the problem of photo-oxygen conditions on perovskite degradation by chemical means.

[0004] In summary, it is of great significance to study and develop a perovskite solar cell and its preparation method that can inhibit perovskite degradation, have low preparation cost, high purity of perovskite cubic phase (α phase), good stability and high photoelectric conversion efficiency. Summary of the invention

[0005] The main purpose of the present invention is to provide a solar cell and a method for preparing the same, so as to solve the problem of high cost and poor effect of using physical means to solve the problem of perovskite degradation under light-oxygen conditions in the prior art.

[0006] In order to achieve the above-mentioned object, the first aspect of the present invention provides a perovskite solar cell, which comprises a transparent conductive substrate, a first carrier transport layer, a perovskite active layer, a photo-oxidation protection layer, a second carrier transport layer and a metal electrode layer stacked in sequence; the material of the photo-oxidation protection layer comprises a compound represented by general formula (I):

[0007]

[0008] X1 is selected from a connecting bond, or a C1-C6 straight or branched alkylene group; R1, R2, R3, R4 and R5 are each independently selected from a hydrogen atom, a halogen atom or Wherein, X2 is selected from a connecting bond, or a C1-C6 straight chain or branched alkylene group.

[0009] Further, X1 is selected from a connecting bond, or a C1-C6 straight-chain alkylene group, preferably a methylene group, an ethylene group or a n-propylene group; preferably, R1 and R5 are each independently selected from hydrogen or an aldehyde group.

[0010] Further, R1 and R3 are both halogen atoms and R2, R4 and R5 are not halogen atoms, or R2 and R4 are both halogen atoms and R1, R3 and R5 are not halogen atoms, or R3 and R5 are both halogen atoms and R1, R2 and R4 are not halogen atoms.

[0011] Furthermore, X2 is selected from a connecting bond, or a C1-C6 straight-chain alkylene group.

[0012] Furthermore, the halogen atom is F.

[0013] Furthermore, the compound represented by general formula (I) is selected from one or more of the following compounds: benzaldehyde, phenylacetaldehyde, phenylpropionaldehyde, 4-phenylbutyraldehyde, terephthalaldehyde, 2-fluorobenzaldehyde, and 3,5-difluorobenzaldehyde.

[0014] Furthermore, the first carrier transport layer is a hole transport layer, and the second carrier transport layer is an electron transport layer.

[0015] Furthermore, the thickness of the photo-oxidation protection layer is 10-50 nm; preferably, the band gap of the photo-oxidation protection layer is 1.65-3.3 eV.

[0016] Furthermore, the thickness of the hole transport layer is 10 to 30 nm.

[0017] Furthermore, the thickness of the perovskite active layer is 0.5-1 μm.

[0018] Furthermore, the thickness of the electron transport layer is 10 to 30 nm.

[0019] Furthermore, the thickness of the metal electrode layer is 10 to 1000 nm.

[0020] Furthermore, the transparent conductive substrate is selected from ITO conductive glass, FTO conductive glass or AZO conductive glass, and preferably the sheet resistance of the conductive surface of the transparent conductive substrate is 150-500Ω / sq.

[0021] Furthermore, the band gap of the perovskite active layer is 1.78 to 2.03 eV; preferably, the material of the perovskite active layer is ABX3, wherein A is selected from CH3NH3 + NH=CHNH3 + and Cs + One or more of the group consisting of, B is Pb 2+ , X is selected from Cl - Br - and I - One or more of the groups.

[0022] Further, the material of the first carrier transport layer is selected from one or more of the group consisting of (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, nickel oxide, cuprous oxide, cuprous iodide and cuprous thiocyanate.

[0023] Furthermore, the material of the second carrier transport layer is selected from C 60 , PCBM and 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline.

[0024] Furthermore, the material of the metal electrode layer is selected from one or more of the group consisting of silver, copper and gold.

[0025] Furthermore, a cathode buffer layer and a transparent conductive oxide layer are included between the second carrier transport layer and the metal electrode layer, the cathode buffer layer is arranged between the second carrier transport layer and the transparent conductive oxide layer, and the transparent conductive oxide layer is arranged between the cathode buffer layer and the metal electrode layer; preferably, the thickness of the cathode buffer layer is 10 to 20 nm; preferably, the thickness of the transparent conductive oxide layer is 5 to 20 nm; preferably, the material of the cathode buffer layer is selected from one or more of the group consisting of 3,3'-(1,3,8,10-tetraanthrone[2,1,9-DEF:6,5,10-D'E'F']diisoquinoline-2,9(1H,3H,8H,10H)-diyl)bis(N,N-dimethylpropane-1-amine oxide), ethoxylated polyethyleneimine, poly[3-(6-trimethylammoniumhexyl)thiophene] and tin oxide. Preferably, the material of the transparent conductive oxide layer is selected from indium zinc oxide and / or fluorine-doped tin oxide.

[0026] The second aspect of the present application also provides a method for preparing the above-mentioned perovskite solar cell provided by the present application, and the preparation method comprises: step S1, preparing a transparent conductive substrate for standby use; step S2, preparing a first carrier transport layer on the surface of one side of the conductive surface of the transparent conductive substrate; step S3, preparing a perovskite active layer on the surface of the first carrier transport layer away from the transparent conductive substrate; step S4, coating a solution containing a compound represented by general formula (I) on the surface of the perovskite active layer away from the first carrier transport layer, and obtaining a photo-oxidation protective layer after drying; step S5, preparing a second carrier transport layer on the surface of the photo-oxidation protective layer away from the perovskite active layer; step S6, preparing a metal electrode layer on the surface of the second carrier transport layer away from the photo-oxidation protective layer to obtain a perovskite solar cell.

[0027] Further, step S4 comprises: mixing the compound represented by general formula (I) with a solvent to obtain a mixed solution; spin coating or spraying the mixed solution on the surface of the perovskite active layer away from the first carrier transport layer, and obtaining a photo-oxidation protective layer after drying.

[0028] Furthermore, the mass concentration of the solution containing the compound represented by general formula (I) is 0.1 to 5 mg / mL.

[0029] Furthermore, the coating is performed by spin coating, and preferably the spin coating speed is 3000-6000 rpm and the time is 10-30 s.

[0030] Furthermore, the coating is carried out by spraying, and preferably, the distance between the nozzle used in the spraying process and the surface of the side of the perovskite active layer away from the first carrier transport layer is 1 to 3 cm, the pressure is 20 to 100 kPa, and the spray density is 1000 to 5000 g / cm 3 , time is 10 to 50 seconds.

[0031] Furthermore, the solvent is selected from one or more of the group consisting of methanol, ethanol, isopropanol, n-butanol and isooctyl alcohol.

[0032] Furthermore, the drying temperature is 90 to 180° C., and the drying time is 5 to 10 minutes.

[0033] Furthermore, between step S5 and step S6, the method also includes: preparing a cathode buffer layer on the surface of the second carrier transport layer away from the photo-oxygen protection layer; preparing a transparent conductive oxide layer on the surface of the cathode buffer layer away from the second carrier transport layer; preferably, the cathode buffer layer is prepared by sputtering; preferably, the transparent conductive oxide layer is prepared by physical vapor deposition or chemical vapor deposition, and more preferably, the physical vapor deposition method is sputtering.

[0034] The third aspect of the present application also provides a perovskite / crystalline silicon tandem solar cell, which comprises the above-mentioned perovskite solar cell and a crystalline silicon bottom cell provided in the present application.

[0035] The fourth aspect of the present application also provides a method for preparing the above-mentioned perovskite / crystalline silicon stacked solar cell provided in the present application, the preparation method comprising: providing a crystalline silicon bottom cell, optionally preparing a transparent conductive layer on one side surface of the crystalline silicon bottom cell, and sequentially preparing a first carrier transport layer, a perovskite active layer, a photo-oxygen protection layer, a second carrier transport layer and a metal electrode layer on the side surface of the transparent conductive layer away from the crystalline silicon bottom cell, the preparation method of the first carrier transport layer, the perovskite active layer, the photo-oxygen protection layer, the second carrier transport layer and the metal electrode layer is the same as the preparation method in the above-mentioned perovskite solar cell provided in the present application; the crystalline silicon bottom cell is selected from HJT cell, TOPCon cell or IBC cell.

[0036] Furthermore, the preparation method further comprises: preparing a cathode buffer layer on the surface of the second carrier transport layer away from the photo-oxidation protection layer, preferably preparing the cathode buffer layer by sputtering.

[0037] Furthermore, the preparation method also includes: preparing a transparent conductive oxide layer on the surface of the cathode buffer layer away from the second carrier transport layer, preferably using physical vapor deposition or chemical vapor deposition to prepare the transparent conductive oxide layer, and more preferably the physical vapor deposition method is sputtering.

[0038] Compared with the method of using physical means to solve the decomposition problem of perovskite under light-oxidation conditions in the prior art to improve the stability and photoelectric conversion efficiency of perovskite solar cells or perovskite / crystalline silicon stacked solar cells, the technical solution of the present invention is applied, and the perovskite solar cell provided by the present application includes a light-oxidation protective layer, wherein the material of the light-oxidation protective layer includes a compound shown in the general formula (I). The phenyl or phenylene group contained in the compound shown in the general formula (I) is hydrophobic, thereby improving the hydrophobicity of the light-oxidation protective layer; the aldehyde group contained therein can undergo an oxidation reaction with oxygen (especially oxygen around the perovskite lattice) under the drive of visible light, consume oxygen, thereby inhibiting the degradation of the perovskite active layer by oxygen; at the same time, the energy released by the oxidation reaction can induce heterogeneous nucleation of the perovskite lattice in the perovskite active layer, reduce the nucleation barrier, thereby promoting the nucleation and crystallization of the perovskite cubic phase (α phase), inhibiting the formation of the non-perovskite phase (δ phase), and thus improving the purity of the α phase in the perovskite active layer. Compared with other structures, introducing the compound with the above-mentioned specific structure into the photo-oxygen protective layer and introducing the photo-oxygen protective layer into the perovskite solar cell can, on the one hand, improve the hydrophobicity of the perovskite solar cell, promote the nucleation and crystallization of the perovskite cubic phase (α phase), and inhibit the formation of the non-perovskite phase (δ phase), thereby improving the purity of the α phase in the perovskite active layer; on the other hand, it can also play the role of passivation defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0040] Figure 1 A schematic diagram of the stacked structure of a perovskite solar cell in one embodiment of the present application is shown;

[0041] Figure 2 A schematic diagram of a stacked structure of a perovskite solar cell in another embodiment of the present application is shown;

[0042] Figure 3 A schematic diagram of the stacked structure of a perovskite / crystalline silicon stacked solar cell in one embodiment of the present application is shown.

[0043] The above drawings include the following reference numerals:

[0044] 10. Transparent conductive substrate; 20. First carrier transport layer; 30. Perovskite active layer; 40. Photo-oxygen protection layer; 50. Second carrier transport layer; 60. Metal electrode layer; 70. Cathode buffer layer; 80. Transparent conductive oxide layer; 90. Crystalline silicon bottom cell; 11. Transparent conductive layer. DETAILED DESCRIPTION

[0045] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0046] As described in the background art, the existing methods of using physical means to solve the degradation of perovskite under light-oxygen conditions have the problems of high cost and poor effect. In order to solve the above technical problems, the first aspect of the present application provides a perovskite solar cell, such as Figure 1 As shown, the perovskite solar cell includes a transparent conductive substrate 10, a first carrier transport layer 20, a perovskite active layer 30, a photo-oxidation protection layer 40, a second carrier transport layer 50 and a metal electrode layer 60 which are stacked in sequence; the material of the photo-oxidation protection layer 40 includes a compound represented by general formula (I):

[0047]

[0048] X1 is selected from a connecting bond, or a C1-C6 straight or branched alkylene group; R1, R2, R3, R4 and R5 are each independently selected from a hydrogen atom, a halogen atom or Wherein, X2 is selected from a connecting bond, or a C1-C6 straight chain or branched alkylene group.

[0049] The perovskite solar cell provided in the present application includes a photo-oxidation protective layer 40, wherein the material of the photo-oxidation protective layer 40 includes a compound shown in the general formula (I). The phenyl or phenylene group contained in the compound shown in the general formula (I) is hydrophobic, thereby improving the hydrophobicity of the photo-oxidation protective layer 40; the aldehyde group contained therein can undergo an oxidation reaction with oxygen (especially oxygen around the perovskite lattice) under the drive of visible light, consume oxygen, thereby inhibiting the degradation of the perovskite active layer 30 by oxygen; at the same time, the energy released by the oxidation reaction can induce heterogeneous nucleation of the perovskite lattice in the perovskite active layer 30, reduce the nucleation barrier, thereby promoting the nucleation and crystallization of the perovskite cubic phase (α phase), inhibiting the generation of the non-perovskite phase (δ phase), and thereby improving the purity of the α phase in the perovskite active layer 30. Compared with other structures, introducing the compound having the above-mentioned specific structure into the photo-oxygen protective layer 40 and introducing the photo-oxygen protective layer 40 into the perovskite solar cell can, on the one hand, improve the hydrophobicity of the perovskite solar cell, promote the nucleation and crystallization of the perovskite cubic phase (α phase), and inhibit the formation of the non-perovskite phase (δ phase), thereby improving the purity of the α phase in the perovskite active layer 30; on the other hand, it can also play the role of passivation defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0050] In a preferred embodiment, X1 includes but is not limited to a connecting bond, or a C1-C6 straight-chain alkylene group, preferably a methylene group, an ethylene group or a n-propylene group; R1 and R5 each independently include but are not limited to hydrogen or an aldehyde group. Compared with other types, limiting the types of X1, R1 and R5 within the above range is beneficial to improving the oxidation reaction activity of the compound represented by the general formula (I) while improving its stability, thereby improving the structural stability of the photo-oxidation protection layer 40, improving its reaction efficiency of oxidation reaction with oxygen driven by visible light, improving the ability to induce heterogeneous nucleation of perovskite crystals, and improving the purity of the α phase in the perovskite active layer 30, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0051] In order to further improve the oxidation reaction activity of the compound represented by general formula (I), further improve the reaction efficiency of its oxidation reaction with oxygen under the drive of visible light, thereby further improving the purity of the α phase in the perovskite active layer 30, and further improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell, preferably, X2 is selected from a connecting bond, or a straight-chain alkylene group of C1 to C6.

[0052] In a preferred embodiment, R1 and R3 are both halogen atoms and R2, R4 and R5 are not halogen atoms, or R2 and R4 are both halogen atoms and R1, R3 and R5 are not halogen atoms, or R3 and R5 are both halogen atoms and R1, R2 and R4 are not halogen atoms. Compared with other types, the use of the above types of R1, R2, R3, R4 and R5 is conducive to improving the hydrophobicity of the compound represented by general formula (I), thereby improving the moisture resistance of the photo-oxygen protective layer 40, and further improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0053] In order to further improve the hydrophobicity of the compound represented by general formula (I), thereby further improving the moisture resistance of the photo-oxygen protection layer 40, and further improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell, preferably, the halogen atom is F.

[0054] In a preferred embodiment, the compound represented by general formula (I) includes but is not limited to one or more of the following compounds: benzaldehyde, phenylacetaldehyde, phenylpropionaldehyde, 4-phenylbutyraldehyde, terephthalaldehyde, 2-fluorobenzaldehyde, and 3,5-difluorobenzaldehyde.

[0055] Compared with other types, compounds with the above structure have higher oxidation reaction activity, more stable chemical structure and better hydrophobicity. Introducing them into the photo-oxygen protection layer 40 is beneficial to improving the reaction efficiency of oxidation reaction with oxygen driven by visible light, and is beneficial to improving the ability to induce heterogeneous nucleation of perovskite crystals, and is beneficial to improving the purity of the α phase in the perovskite active layer 30, which in turn is beneficial to improving the stability, durability and photoelectric conversion efficiency of perovskite solar cells.

[0056] The titanium ore solar cell provided in the present application may be an inverted perovskite solar cell. In a preferred embodiment, the first carrier transport layer 20 is a hole transport layer, and the second carrier transport layer 50 is an electron transport layer. Compared with the formal structure (nip), the inverted structure (pin) perovskite solar cell has higher photoelectric conversion efficiency and better stability.

[0057] In a preferred embodiment, the thickness of the photo-oxidation protection layer 40 is 10 to 50 nm. The thickness of the photo-oxidation protection layer 40 includes but is not limited to the above range. Limiting it within the above range is conducive to better exerting the effect of the compound represented by the general formula (I), thereby facilitating improving the reaction efficiency of its oxidation reaction with oxygen under the drive of visible light, facilitating improving the ability to induce heterogeneous nucleation of perovskite crystals, facilitating improving the purity of the α phase in the perovskite active layer 30, facilitating better exerting its role in passivating defects, and further facilitating improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0058] In order to better match the energy level structure of the perovskite active layer 30 , preferably, the band gap of the photo-oxidation protection layer 40 is 1.65 to 3.3 eV.

[0059] In order to further improve the stability, durability and photoelectric conversion efficiency of perovskite solar cells, in a preferred embodiment, the thickness of the hole transport layer is 10 to 30 nm; the thickness of the perovskite active layer 30 is 0.5 to 1 μm; the thickness of the electron transport layer is 10 to 30 nm; and the thickness of the metal electrode layer 60 is 10 to 1000 nm.

[0060] The present application has no particular limitation on the type of the transparent conductive substrate 10, as long as it is conductive and has high light transmittance. In a preferred embodiment, the transparent conductive substrate 10 includes but is not limited to ITO conductive glass, FTO conductive glass or AZO conductive glass.

[0061] In order to improve the conductivity of the transparent conductive substrate 10 and thus further improve the photoelectric conversion efficiency of the perovskite solar cell, preferably, the sheet resistance of the conductive surface of the transparent conductive substrate 10 is 150-500Ω / sq.

[0062] In a preferred embodiment, the band gap of the perovskite active layer 30 is 1.78 to 2.03 eV. The band gap of the perovskite active layer 30 includes but is not limited to the above range, and limiting it within the above range is conducive to improving the light absorption efficiency of the perovskite material, and is conducive to matching the energy level structure of the photo-oxygen protective layer 40, thereby facilitating the improvement of the photoelectric conversion efficiency of the perovskite solar cell.

[0063] In order to further improve the light absorption efficiency of the perovskite material and the photoelectric conversion efficiency of the perovskite solar cell, preferably, the material of the perovskite active layer 30 is ABX3, wherein A includes but is not limited to CH3NH3 + NH=CHNH3 + and Cs + One or more of the group consisting of, B is Pb 2+ , X includes but is not limited to Cl - Br - and I - One or more of the groups.

[0064] In a preferred embodiment, the material of the first carrier transport layer 20 includes, but is not limited to, one or more of the group consisting of (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene) (Spiro-OMeTAD), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA), poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), nickel oxide, cuprous oxide, cuprous iodide and cuprous thiocyanate. Compared with other types, the use of the above-mentioned first carrier transport materials is conducive to improving the photoelectric conversion efficiency and stability of perovskite solar cells.

[0065] In order to improve the photoelectric conversion efficiency and stability of the perovskite solar cell, in a preferred embodiment, the material of the second carrier transport layer 50 includes but is not limited to C 60 One or more of the group consisting of (footballene), PCBM (fullerene derivative) and 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP).

[0066] In a preferred embodiment, the material of the metal electrode layer 60 includes, but is not limited to, one or more of the group consisting of silver, copper and gold. Compared with other types, the use of the above-mentioned types of metal electrode materials is conducive to improving the conductivity of the metal electrode layer 60, thereby facilitating the improvement of the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0067] In a preferred embodiment, Figure 2As shown, a cathode buffer layer 70 and a transparent conductive oxide layer 80 are further included between the second carrier transport layer 50 and the metal electrode layer 60. The cathode buffer layer 70 is disposed between the second carrier transport layer 50 and the transparent conductive oxide layer 80, and the transparent conductive oxide layer 80 is disposed between the cathode buffer layer 70 and the metal electrode layer 60. The arrangement of the cathode buffer layer 70 and the transparent conductive oxide layer 80 is conducive to improving the electron transmission efficiency and the passivation effect on the interface defects, and can also play a role in protecting the perovskite active layer 30, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0068] In a preferred embodiment, the thickness of the cathode buffer layer 70 is 10 to 20 nm. The thickness of the cathode buffer layer 70 includes but is not limited to the above range, and limiting it within the above range is conducive to improving the electron transmission efficiency and the passivation effect on interface defects, thereby improving the photoelectric conversion efficiency and stability of the titanium ore solar cell.

[0069] In order to improve the electron transfer efficiency, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell, in a preferred embodiment, the thickness of the transparent conductive oxide layer 80 is 5 to 20 nm.

[0070] In a preferred embodiment, the material of the cathode buffer layer 70 includes, but is not limited to, one or more of the group consisting of 3,3'-(1,3,8,10-tetraanthraquinone [2,1,9-DEF:6,5,10-D'E'F'] diisoquinoline-2,9 (1H,3H,8H,10H)-diyl) bis (N,N-dimethylpropane-1-amine oxide) (PDINO), ethoxylated polyethyleneimine (PEIE), poly [3- (6-trimethylammoniumhexyl) thiophene] (P3TMAHT) and tin oxide. Compared with other types, the use of the above types of materials is conducive to improving the passivation effect of the interface defects, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0071] In a preferred embodiment, the material of the transparent conductive oxide layer 80 includes but is not limited to indium zinc oxide (IZO) and / or fluorine-doped tin oxide (FTO). Compared with other types, the use of the above types of materials is conducive to improving the electron transmission efficiency, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0072] The second aspect of the present application also provides a method for preparing the above-mentioned perovskite solar cell provided by the present application, and the preparation method comprises: step S1, preparing a transparent conductive substrate 10 for standby use; step S2, preparing a first carrier transport layer 20 on the surface of one side of the conductive surface of the transparent conductive substrate 10; step S3, preparing a perovskite active layer 30 on the surface of the first carrier transport layer 20 away from the transparent conductive substrate 10; step S4, coating a solution containing a compound represented by general formula (I) on the surface of the perovskite active layer 30 away from the first carrier transport layer 20, and obtaining a photo-oxidation protective layer 40 after drying; step S5, preparing a second carrier transport layer 50 on the surface of the photo-oxidation protective layer 40 away from the perovskite active layer 30; step S6, preparing a metal electrode layer 60 on the surface of the second carrier transport layer 50 away from the photo-oxidation protective layer 40, to obtain a perovskite solar cell.

[0073] The above-mentioned preparation method can be used to obtain a perovskite solar cell with a stacked structure, and the photo-oxidation protection layer 40 containing the compound represented by the general formula (I) can be arranged in the stacked structure of the perovskite solar cell through step S4; wherein the phenyl or phenylene group contained in the compound represented by the general formula (I) is hydrophobic, thereby improving the hydrophobicity of the photo-oxidation protection layer 40; the aldehyde group contained therein can undergo an oxidation reaction with oxygen (especially oxygen around the perovskite lattice) under the drive of visible light, consume oxygen, thereby inhibiting the degradation of the perovskite active layer 30 by oxygen; at the same time, the energy released by the oxidation reaction can induce heterogeneous nucleation of the perovskite lattice in the perovskite active layer 30, reduce the nucleation barrier, thereby promoting the nucleation and crystallization of the perovskite cubic phase (α phase), inhibiting the formation of the non-perovskite phase (δ phase), and thereby improving the purity of the α phase in the perovskite active layer 30. Introducing the photo-oxygen protective layer 40 containing the compound represented by the general formula (I) into the perovskite solar cell can, on the one hand, improve the hydrophobicity of the perovskite solar cell, promote the nucleation and crystallization of the perovskite cubic phase (α phase), and inhibit the formation of the non-perovskite phase (δ phase), thereby improving the purity of the α phase in the perovskite active layer 30; on the other hand, it can also play a role in passivating defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0074] In a preferred embodiment, in the above-mentioned preparation method provided by the present application, step S1 includes: depositing a transparent conductive substrate 10 containing a conductive surface on one side of a transparent glass substrate by physical vapor deposition or chemical vapor deposition, preferably the physical vapor deposition method is sputtering; step S2 includes: preparing a first carrier transport layer 20 by spin coating, evaporation or inkjet printing; step S3 includes: preparing a perovskite active layer 30 on the side of the first carrier layer away from the transparent conductive substrate 10 by spin coating, scraping or spray deposition, and obtaining the perovskite active layer 30 after annealing; step S5 includes: preparing a second carrier transport layer 50 by spin coating or evaporation; step S6 includes: preparing a metal electrode layer 60 by screen printing or evaporation. Compared with other methods, the above method is conducive to improving the film forming property and uniformity of each film layer, and can obtain a higher quality film layer.

[0075] In order to further improve the film-forming property of the perovskite active layer 30 and inhibit cracking thereof, preferably, the annealing treatment is performed at a temperature of 90 to 180° C. and for a time of 5 to 10 minutes.

[0076] In a preferred embodiment, step S4 comprises: mixing the compound represented by general formula (I) with a solvent to obtain a mixed solution; spin coating or spray coating the mixed solution on the surface of the side of the perovskite active layer 30 away from the first carrier transport layer 20, and drying to obtain the photo-oxidation protective layer 40. Compared with other methods, the use of spin coating or spray coating to prepare the photo-oxidation protective layer 40 is conducive to improving the distribution uniformity of the mixed solution on the surface of the side of the perovskite active layer 30 away from the first carrier transport layer 20, thereby facilitating the acquisition of a photo-oxidation protective layer 40 with uniform thickness; at the same time, the above method is simple to operate and has strong controllability, which is conducive to improving production efficiency and reducing production costs.

[0077] In a preferred embodiment, the mass concentration of the solution containing the compound represented by the general formula (I) is 0.1 to 5 mg / mL. The mass concentration of the solution containing the compound represented by the general formula (I) includes but is not limited to the above range, and limiting it within the above range is conducive to improving the dispersibility of the compound represented by the general formula (I), which is conducive to better exerting its role, and further conducive to improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0078] In a preferred embodiment, the coating is performed by spin coating, and the spin coating speed is 3000-6000 rpm and the time is 10-30 s. The spin coating speed and time include but are not limited to the above ranges. Limiting them within the above ranges is conducive to improving the distribution uniformity of the mixed solution on the surface of the side of the perovskite active layer 30 away from the first carrier transport layer 20, thereby facilitating the acquisition of a more uniform thickness of the photo-oxidation protective layer 40, and improving the distribution uniformity of the compound represented by the general formula (I) in the photo-oxidation protective layer 40, and also facilitating the improvement of the spin coating efficiency.

[0079] In a preferred embodiment, the coating is carried out by spraying. During the spraying process, the distance between the nozzle and the surface of the side of the perovskite active layer 30 away from the first carrier transport layer 20 is 1 to 3 cm, the pressure is 20 to 100 kPa, and the spray density is 1000 to 5000 g / cm 3 , the time is 10 to 50 seconds. Compared with other ranges, limiting the above process parameters within the above range is conducive to improving the distribution uniformity of the mixed solution on the surface of the side of the perovskite active layer 30 away from the first carrier transport layer 20, thereby facilitating the acquisition of a more uniform thickness of the photo-oxidation protective layer 40, and improving the distribution uniformity of the compound represented by the general formula (I) in the photo-oxidation protective layer 40, and also facilitating the improvement of the spraying efficiency.

[0080] In order to improve the dispersibility of the compound represented by general formula (I) in the solution, in a preferred embodiment, the solvent includes but is not limited to one or more of the group consisting of methanol, ethanol, isopropanol, n-butanol and isooctyl alcohol.

[0081] In a preferred embodiment, the drying temperature is 90-180° C. and the drying time is 5-10 minutes. The drying temperature and time include but are not limited to the above ranges, which are beneficial to improving the removal efficiency of the solvent in the photo-oxidation protective layer 40 .

[0082] In a preferred embodiment, between step S5 and step S6, the following steps are included: preparing a cathode buffer layer 70 on the surface of the second carrier transport layer 50 away from the photo-oxidation protection layer 40; preparing a transparent conductive oxide layer 80 on the surface of the cathode buffer layer 70 away from the second carrier transport layer 50. The cathode buffer layer 70 and the transparent conductive oxide layer 80 can be arranged in the stacked structure of the perovskite solar cell through the above preparation method, which is beneficial to improve the electron transmission efficiency and the passivation effect on the interface defects, and can also protect the perovskite active layer 30, thereby improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0083] In order to improve the uniformity of the prepared film layer, in a preferred embodiment, the cathode buffer layer 70 is prepared by sputtering.

[0084] In a preferred embodiment, the transparent conductive oxide layer 80 is prepared by physical vapor deposition or chemical vapor deposition, and preferably the physical vapor deposition method is sputtering. Compared with other methods, the above preparation method is conducive to obtaining a transparent conductive oxide layer 80 with better film quality.

[0085] The third aspect of the present application also provides a perovskite / crystalline silicon tandem solar cell, such as Figure 3 As shown, the perovskite / crystalline silicon tandem solar cell includes the above-mentioned perovskite solar cell and the crystalline silicon bottom cell 90 provided in the present application.

[0086] The laminated structure of the perovskite / crystalline silicon laminated solar cell provided in the present application includes a photo-oxidation protective layer 40, wherein the material of the photo-oxidation protective layer 40 includes a compound shown in the general formula (I). The phenyl or phenylene group contained in the compound shown in the general formula (I) is hydrophobic, thereby improving the hydrophobicity of the photo-oxidation protective layer 40; the aldehyde group contained therein can undergo an oxidation reaction with oxygen (especially oxygen around the perovskite lattice) under the drive of visible light, consume oxygen, thereby inhibiting the degradation of the perovskite active layer 30 by oxygen; at the same time, the energy released by the oxidation reaction can induce heterogeneous nucleation of the perovskite lattice in the perovskite active layer 30, reduce the nucleation barrier, thereby promoting the nucleation and crystallization of the perovskite cubic phase (α phase), inhibiting the formation of the non-perovskite phase (δ phase), and thereby improving the purity of the α phase in the perovskite active layer 30. Introducing the photo-oxygen protection layer 40 containing the above-mentioned specific structure compound into the perovskite / crystalline silicon tandem solar cell can, on the one hand, improve the hydrophobicity of the perovskite / crystalline silicon tandem solar cell, promote the nucleation and crystallization of the perovskite cubic phase (α phase), and inhibit the formation of the non-perovskite phase (δ phase), thereby improving the purity of the α phase in the perovskite active layer 30; on the other hand, it can also play a role in passivating defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0087] The fourth aspect of the present application also provides a method for preparing the above-mentioned perovskite / crystalline silicon stacked solar cell provided in the present application, the preparation method comprising: providing a crystalline silicon bottom cell 90, optionally preparing a transparent conductive layer 11 on one side surface of the crystalline silicon bottom cell 90, and sequentially preparing a first carrier transport layer 20, a perovskite active layer 30, a photo-oxygen protection layer 40, a second carrier transport layer 50 and a metal electrode layer 60 on the side surface of the transparent conductive layer 11 away from the crystalline silicon bottom cell 90, the preparation method of the first carrier transport layer 20, the perovskite active layer 30, the photo-oxygen protection layer 40, the second carrier transport layer 50 and the metal electrode layer 60 is the same as the preparation method in the above-mentioned perovskite solar cell provided in the present application.

[0088] The above-mentioned preparation method can be used to obtain a perovskite / crystalline silicon stacked solar cell with a stacked structure, and at the same time, the photo-oxygen protection layer 40 containing the compound represented by the general formula (I) can be arranged in the stacked structure of the perovskite / crystalline silicon stacked solar cell; the photo-oxygen protection layer 40 containing the compound represented by the general formula (I) is introduced into the perovskite / crystalline silicon stacked solar cell, which can improve the hydrophobicity of the perovskite / crystalline silicon stacked solar cell and the purity of the α phase in the perovskite active layer 30 on the one hand, and can also play a role in passivating defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite / crystalline silicon stacked solar cell.

[0089] In a preferred embodiment, the crystalline silicon bottom cell 90 includes but is not limited to a HJT cell (heterojunction cell), a TOPCon cell (tunneling oxide passivation contact cell) or an IBC cell (interdigitated back contact cell). Compared with other types, the use of the above-mentioned type of crystalline silicon bottom cell 90 is conducive to improving the stability and photoelectric conversion efficiency of the perovskite / crystalline silicon tandem solar cell.

[0090] In a preferred embodiment, the transparent conductive layer 11 is optionally prepared on one side surface of the crystalline silicon bottom cell 90 , which means that when the crystalline silicon bottom cell 90 is a HJT cell, a TOPCon cell, or an IBC cell, the transparent conductive layer 11 does not need to be prepared on one side surface of the crystalline silicon bottom cell 90 .

[0091] In a preferred embodiment, the preparation method further includes: preparing a cathode buffer layer 70 on the surface of the second carrier transport layer 50 away from the photo-oxygen protection layer 40. The cathode buffer layer 70 can be arranged in the laminated structure of the perovskite / crystalline silicon laminated solar cell through the above preparation method, so as to improve its passivation effect on interface defects, and at the same time, it can also play a role in protecting the perovskite active layer 30, thereby helping to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0092] In order to improve the uniformity of the prepared film layer, preferably, the cathode buffer layer 70 is prepared by sputtering.

[0093] In a preferred embodiment, the preparation method further includes: preparing a transparent conductive oxide layer 80 on the surface of the cathode buffer layer 70 away from the second carrier transport layer 50. Through the above preparation method, the transparent conductive oxide layer 80 can be arranged in the stacked structure of the perovskite / crystalline silicon stacked solar cell, which is beneficial to improve the electron transmission efficiency, and further beneficial to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0094] In order to improve the film-forming property and uniformity of the prepared film layer and obtain a film layer with higher quality, preferably, the transparent conductive oxide layer 80 is prepared by physical vapor deposition or chemical vapor deposition, and more preferably, the physical vapor deposition method is sputtering.

[0095] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0096] Example 1

[0097] A method for preparing a perovskite / crystalline silicon tandem solar cell comprises the following steps:

[0098] (1) providing a crystalline silicon bottom cell 90, wherein the stacked structure of the crystalline silicon bottom cell 90 is represented by: back Ag / TCO / p-polycrystalline silicon / intrinsic amorphous silicon / n-Si / intrinsic amorphous silicon / n-polycrystalline silicon;

[0099] (2) preparing a transparent conductive layer 11: sputtering ITO onto the surface of the n-polycrystalline silicon layer of the crystalline silicon bottom cell 90 prepared in step (1) on the side away from the intrinsic amorphous silicon layer to obtain an ITO layer with a thickness of 10 nm, wherein the vacuum degree is 8 Pa, the sputtering power is 60 W, the sputtering time is 500 min, and the argon gas flow rate is 700 sccm;

[0100] (3) Preparation of hole transport layer: NiO x The ITO layer prepared in step (2) is sputtered and deposited on the side of the surface away from the crystalline silicon bottom cell 90 to obtain a NiO layer with a thickness of 20 nm. x layer, wherein the vacuum degree is 7.5 Pa, the sputtering power is 80 W, the sputtering time is 900 min, and the argon gas flow rate is 400 sccm;

[0101] (4) Preparation of perovskite active layer 30: PbI2, MAI, FABr and CsBr powders were dispersed in 10 mL of isopropanol at a molar ratio of 5:4:5:1, and stirred for 5 h to prepare a perovskite precursor solution; the perovskite precursor solution was spin-coated on the NiO prepared in step (3). x On the surface of the side of the layer away from the ITO layer, it was first spin-coated at 3000 rpm for 20 seconds, transferred to a 90°C heating plate, annealed for 5 minutes, and then spin-coated at 5000 rpm for 30 seconds; then transferred to a 110°C heating plate and annealed for 10 minutes to obtain a (Cs 0.1 FA 0.5 MA 0.0.4 )Pb(I 0.8 Br 0.2 )3 perovskite active layer 30;

[0102] (5) Preparation of photo-oxidation protective layer 40: 0.5 mg of benzaldehyde (CAS: 100-52-7) was dissolved in 1 mL of ethanol to obtain a mixed solution, and the mixed solution was spin-coated on the perovskite active layer 30 prepared in step (4) away from NiO x On one side of the layer, the spin coating speed is 3000 rpm, and after 20 seconds of spin coating, it is transferred to a 90° C. oven and dried for 10 minutes to obtain a photo-oxidation protective layer 40 with a thickness of 20 nm;

[0103] (6) Preparation of electron transport layer: The photo-oxidation protective layer 40 prepared in step (5) is formed on a surface away from the perovskite active layer 30. The BCP layer with a thickness of 20 nm was obtained by evaporation at a deposition rate of ;

[0104] (7) Preparing a cathode buffer layer 70: sputtering SnO2 onto the surface of the BCP layer prepared in step (6) away from the photo-oxidation protective layer 40 to obtain a SnO2 layer with a thickness of 20 nm, wherein the vacuum degree is 4.8 Pa, the sputtering power is 35 W, the sputtering time is 60 min, and the argon gas flow rate is 800 sccm;

[0105] (8) Preparing a transparent conductive oxide layer 80: sputtering IZO onto the surface of the SnO2 layer prepared in step (7) away from the BCP layer to obtain an IZO layer with a thickness of 10 nm, wherein the vacuum degree is 6 Pa, the sputtering power is 60 W, the sputtering time is 30 min, and the argon gas flow rate is 850 sccm;

[0106] (9) Preparation of metal electrode layer 60: The IZO layer prepared in step (8) is formed on a surface away from the SnO2 layer. The Ag electrode layer with a thickness of 1 μm was obtained by evaporation at a deposition rate of .

[0107] The effective area of ​​the perovskite / crystalline silicon tandem solar cell prepared in this embodiment is measured to be 100 mm 2 , its laminated structure is as follows Figure 3 shown.

[0108] Example 2

[0109] The difference from Example 1 is that in step (5), an equal amount of phenylacetaldehyde (CAS: 122-78-1) is used to replace benzaldehyde to prepare the photo-oxidation protective layer 40 containing phenylacetaldehyde, and the remaining steps are the same as Example 1.

[0110] Example 3

[0111] The difference from Example 1 is that in step (5), an equal amount of terephthalaldehyde (CAS: 623-27-8) is used to replace benzaldehyde to prepare the photo-oxidation protective layer 40 containing terephthalaldehyde, and the remaining steps are the same as those of Example 1.

[0112] Example 4

[0113] The difference from Example 1 is that in step (5), an equal amount of 3,5-difluorobenzaldehyde (CAS: 32085-88-4) is used to replace benzaldehyde to prepare a photo-oxidation protective layer 40 containing 3,5-difluorobenzaldehyde, and the remaining steps are the same as Example 1.

[0114] Example 5

[0115] The difference from Example 1 is that in step (5), the spin coating speed is 6000 rpm, the time is 30 s, and a photo-oxidation protective layer 40 with a thickness of 10 nm is obtained.

[0116] Example 6

[0117] The difference from Example 1 is that in step (5), the spin coating speed is 3000 rpm, the time is 10 s, and a photo-oxidation protective layer 40 with a thickness of 50 nm is obtained.

[0118] Example 7

[0119] The difference from Example 1 is that in step (5), the spin coating speed is 8000 rpm, the time is 50 s, and a photo-oxidation protective layer 40 with a thickness of 5 nm is obtained.

[0120] Example 8

[0121] A method for preparing a perovskite solar cell, comprising:

[0122] (1) Providing a transparent conductive substrate 10: ultrasonically cleaning an ITO conductive glass with detergent water, deionized water, acetone, and isopropanol solution for 30 minutes, drying it for later use, and then plasma treating the cleaned ITO conductive glass for 30 minutes for later use;

[0123] (2) Preparation of hole transport layer: NiO x The NiO layer with a thickness of 20 nm is deposited by sputtering on the surface of the transparent conductive substrate 10 provided in step (1). x layer, wherein the vacuum degree is 7.5 Pa, the sputtering power is 80 W, the sputtering time is 900 min, and the argon gas flow rate is 400 sccm;

[0124] (3) Preparation of perovskite active layer 30: PbI2, MAI, FABr and CsBr powders were dispersed in 10 mL of isopropanol at a molar ratio of 5:4:5:1, and stirred for 5 h to prepare a perovskite precursor solution; the perovskite precursor solution was spin-coated on the NiO prepared in step (2). x The surface of the layer away from the transparent conductive substrate 10 was first spin-coated at 3000 rpm for 20 seconds, transferred to a heating plate at 90°C, annealed for 5 minutes, and then spin-coated at 5000 rpm for 30 seconds; then transferred to a heating plate at 110°C, annealed for 10 minutes, and a (Cs 0.1 FA 0.5 MA 0.0.4 )Pb(I 0.8 Br 0.2 )3 perovskite active layer 30;

[0125] (4) Preparing a photo-oxidation protective layer 40: dissolving 0.1 mg of benzaldehyde (CAS: 100-52-7) in 1 mL 1000 μL of ethanol to obtain a mixed solution, and spin-coating the mixed solution on the surface of the perovskite active layer 30 obtained in step (3), wherein the spin-coating speed is 4500 rpm. After spin-coating for 30 seconds, the layer is transferred to a 90° C. oven and dried for 10 minutes to obtain a photo-oxidation protective layer 40 with a thickness of 20 nm;

[0126] (5) Preparation of electron transport layer: The photo-oxidation protective layer 40 prepared in step (4) is formed on a surface away from the perovskite active layer 30. The BCP layer with a thickness of 10 nm was obtained by evaporation at a deposition rate of ;

[0127] (6) Preparing a cathode buffer layer 70: sputtering SnO2 onto the surface of the BCP layer prepared in step (5) away from the photo-oxidation protective layer 40 to obtain a SnO2 layer with a thickness of 20 nm, wherein the vacuum degree is 6.8 Pa, the sputtering power is 34 W, the sputtering time is 25 min, and the argon gas flow rate is 640 sccm;

[0128] (7) Preparing a transparent conductive oxide layer 80: sputtering IZO onto the surface of the SnO2 layer obtained in step (6) on the side away from the BCP layer to obtain an IZO layer with a thickness of 10 nm, wherein the vacuum degree is 6 Pa, the sputtering power is 60 W, the sputtering time is 30 min, and the argon gas flow rate is 850 sccm;

[0129] (8) Preparation of metal electrode layer 60: The IZO layer prepared in step (7) is formed on a surface away from the SnO2 layer. The Ag electrode layer with a thickness of 1 μm was obtained by evaporation at a deposition rate of .

[0130] The effective area of ​​the perovskite solar cell prepared in this embodiment is measured to be 10 mm 2 , its laminated structure is as follows Figure 2 shown.

[0131] Example 9

[0132] The difference from Example 1 is that in step (5), the mixed solution is sprayed on the perovskite active layer 30 prepared in step (4) by spraying, away from the NiO x The distance between the nozzle and the perovskite active layer 30 is 1 cm, the pressure is 20 kPa, and the spray density is 1000 g / cm 3 , time is 50s, and a photo-oxidation protective layer 40 with a thickness of 20nm is obtained; the remaining steps are the same as those in Example 1.

[0133] Example 10

[0134] The difference from Example 1 is that in step (5), the mixed solution is sprayed on the perovskite active layer 30 prepared in step (4) by spraying, away from the NiO x The spray head is placed on the surface of one side of the layer, wherein the distance between the nozzle and the perovskite active layer 30 is 3 cm, the pressure is 100 kPa, and the spray density is 5000 g / cm 3 , time is 10s, and a photo-oxidation protective layer 40 with a thickness of 25nm is obtained; the remaining steps are the same as those in Example 1.

[0135] Embodiment 11

[0136] The difference from Example 1 is that in step (5), the mixed solution is sprayed on the perovskite active layer 30 prepared in step (4) by spraying, away from the NiO x The distance between the nozzle and the perovskite active layer 30 is 5 cm, the pressure is 15 kPa, and the spray density is 800 g / cm 3 , time is 7s, and a photo-oxidation protective layer 40 with a thickness of 5nm is obtained; the remaining steps are the same as those in Example 1.

[0137] Example 12

[0138] The difference from Example 1 is that step (7) and step (8) are omitted, a metal electrode layer 60 is prepared on the surface of the BCP layer prepared in step (6) on the side away from the photo-oxidation protection layer 40, and the remaining steps are the same as those in Example 1, thereby obtaining a perovskite / crystalline silicon stacked solar cell without a cathode buffer layer 70 and a transparent conductive oxide layer 80.

[0139] Comparative Example 1

[0140] The difference from Example 1 is that step (5) is omitted, an electron transport layer is prepared on the surface of the perovskite active layer 30 prepared in step (4), and the remaining steps are the same as Example 1. The obtained perovskite / crystalline silicon stacked solar cell does not contain a photo-oxygen protective layer 40.

[0141] Comparative Example 2

[0142] The difference from Example 1 is that step (5) is omitted, an equal amount of benzaldehyde is added as an additive to the perovskite active layer 30 in step (4), and the remaining steps are the same as those in Example 1.

[0143] Comparative Example 3

[0144] The difference from Example 8 is that step (4) is omitted, an electron transport layer is prepared on the surface of the perovskite active layer 30 prepared in step (3), and the remaining steps are the same as those in Example 1. The obtained perovskite solar cell does not contain a photo-oxygen protective layer 40.

[0145] The photovoltaic performance of the perovskite / crystalline silicon tandem solar cells and perovskite solar cells prepared in all the above embodiments and comparative examples of the present application was tested. 2 The JV curve of the perovskite / crystalline silicon tandem solar cell was tested under simulated sunlight conditions using a solar simulator (Newport, Oriel Sol3AClass AAA) and a Keithley 2400 digital source meter. The stability test conditions were as follows: the perovskite / crystalline silicon tandem solar cells prepared in all the above embodiments and comparative examples were placed in air (5-10% RH) at 100 mW / cm 2 The test results are shown in Table 1 below.

[0146] Table 1

[0147]

[0148] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0149] The photoelectric conversion efficiency and the time for PCE to reach 90% of Examples 1 to 4 are all higher than those of Comparative Example 1. It can be seen that introducing the compound having the above-mentioned specific structure into the photo-oxygen protection layer 40, and introducing the photo-oxygen protection layer 40 into the perovskite / crystalline silicon stacked solar cell, on the one hand, can improve the hydrophobicity of the perovskite / crystalline silicon stacked solar cell, promote the nucleation and crystallization of the perovskite cubic phase (α phase), and inhibit the formation of the non-perovskite phase (δ phase), thereby improving the purity of the α phase in the perovskite active layer 30; on the other hand, it can also play a role in passivating defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite / crystalline silicon stacked solar cell.

[0150] The photoelectric conversion efficiency and the time for PCE to reach 90% in Example 1 are both higher than those in Comparative Example 2. It can be seen that compared with introducing the compound represented by the general formula (I) as an additive into the perovskite active layer 30, the present application prepares it into a photo-oxygen protective layer 40 and introduces it into the perovskite / crystalline silicon stacked solar cell. On the one hand, it is beneficial to promote the nucleation and crystallization of the perovskite cubic phase (α phase) and inhibit the formation of the non-perovskite phase (δ phase), thereby facilitating the improvement of the purity of the α phase in the perovskite active layer 30. On the other hand, it is beneficial to play the role of passivation defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0151] Since Example 8 is a single-junction perovskite solar cell, its photoelectric conversion efficiency and stability are lower than those of the perovskite / crystalline silicon heterojunction stacked solar cell in Example 1. At the same time, by comparing Example 8 with Comparative Example 3, it can be seen that the introduction of the compound having the above-mentioned specific structure into the photo-oxygen protective layer 40 and the introduction of the photo-oxygen protective layer 40 into the perovskite solar cell can, on the one hand, promote the nucleation and crystallization of the perovskite cubic phase (α phase) and inhibit the formation of the non-perovskite phase (δ phase), thereby improving the purity of the α phase in the perovskite active layer 30, and on the other hand, can also play a role in passivation defects, thereby improving the stability, durability and photoelectric conversion efficiency of the perovskite solar cell.

[0152] By comparing Examples 1 to 4, it can be seen that compared with other types, the compounds of the above-mentioned specific structure of the present application have higher oxidation reaction activity, more stable chemical structure, and better hydrophobicity. Introducing them into the photo-oxygen protection layer 40 is beneficial to improving the reaction efficiency of the oxidation reaction with oxygen driven by visible light, and is beneficial to improving the ability to induce heterogeneous nucleation of perovskite crystals, and is beneficial to improving the purity of the α phase in the perovskite active layer 30, which is beneficial to improving the stability, durability and photoelectric conversion efficiency of perovskite solar cells.

[0153] By comparing Examples 1, 5 to 7 and 9 to 11, it can be seen that, compared with other ranges, limiting the process parameters for preparing the photo-oxygen protection layer 40 within the above-mentioned range of the present application is beneficial to improving the distribution uniformity of the compound represented by the general formula (I) in the photo-oxygen protection layer 40, and is beneficial to obtaining a photo-oxygen protection layer 40 with a more uniform thickness; compared with other ranges, limiting the thickness of the photo-oxygen protection layer 40 within the above-mentioned range of the present application is beneficial to better exerting the effect of the compound represented by the general formula (I), thereby facilitating improving the reaction efficiency of the oxidation reaction with oxygen driven by visible light, improving the ability to induce heterogeneous nucleation of perovskite crystals, improving the purity of the α phase in the perovskite active layer 30, and better exerting its role in passivating defects, thereby facilitating improving the stability, durability and photoelectric conversion efficiency of the perovskite / crystalline silicon stacked solar cell.

[0154] By comparing Examples 1 and 12, it can be seen that the provision of the cathode buffer layer 70 and the transparent conductive oxide layer 80 is beneficial to improving the electron transmission efficiency and the passivation effect on interface defects, while also being able to protect the perovskite active layer 30, thereby facilitating the improvement of the photoelectric conversion efficiency and stability of the perovskite / crystalline silicon stacked solar cell.

[0155] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0156] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that: The perovskite solar cell comprises a transparent conductive substrate (10), a first carrier transport layer (20), a perovskite active layer (30), a photo-oxidation protection layer (40), a second carrier transport layer (50) and a metal electrode layer (60) which are stacked in sequence; the material of the photo-oxidation protection layer (40) comprises a compound represented by general formula (I): X1 is selected from a connecting bond, or a C1-C6 straight or branched alkylene group; R1, R2, R3, R4 and R5 are each independently selected from a hydrogen atom, a halogen atom or in, X2 is selected from a linking bond, or a C1-C6 straight or branched alkylene group.

2. The perovskite solar cell according to claim 1, characterized in that The X1 is selected from a connecting bond, or a C1-C6 straight-chain alkylene group, preferably a methylene group, an ethylene group or a n-propylene group; Preferably, said R1 and said R5 are each independently selected from hydrogen or aldehyde; Preferably, R1 and R3 are both halogen atoms and R2, R4 and R5 are not halogen atoms, or R2 and R4 are both halogen atoms and R1, R3 and R5 are not halogen atoms, or R3 and R5 are both halogen atoms and R1, R2 and R4 are not halogen atoms; Preferably, X2 is selected from a connecting bond, or a C1-C6 straight chain alkylene group; Preferably, the halogen atom is F.

3. The perovskite solar cell according to claim 1, characterized in that The compound represented by the general formula (I) is selected from one or more of the following compounds: benzaldehyde, phenylacetaldehyde, phenylpropionaldehyde, 4-phenylbutyraldehyde, terephthalaldehyde, 2-fluorobenzaldehyde, and 3,5-difluorobenzaldehyde.

4. The perovskite solar cell according to any one of claims 1 to 3, characterized in that The first carrier transport layer (20) is a hole transport layer, and the second carrier transport layer (50) is an electron transport layer; Preferably, the thickness of the photo-oxidation protective layer (40) is 10 to 50 nm; Preferably, the band gap of the photo-oxidation protective layer (40) is 1.65 to 3.3 eV; Preferably, the thickness of the hole transport layer is 10 to 30 nm; Preferably, the thickness of the perovskite active layer (30) is 0.5-1 μm; Preferably, the thickness of the electron transport layer is 10 to 30 nm; Preferably, the thickness of the metal electrode layer (60) is 10 to 1000 nm; Preferably, the transparent conductive substrate (10) is selected from ITO conductive glass, FTO conductive glass or AZO conductive glass, and preferably the sheet resistance of the conductive surface of the transparent conductive substrate (10) is 150 to 500 Ω / sq; Preferably, the band gap of the perovskite active layer (30) is 1.78-2.03 eV; preferably, the material of the perovskite active layer (30) is ABX3, wherein A is selected from CH3NH3 + NH=CHNH3 + and Cs + One or more of the group consisting of, B is Pb 2+ , X is selected from Cl - Br - and I - One or more of the groups consisting of; Preferably, the material of the first carrier transport layer (20) is selected from one or more of the group consisting of (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, nickel oxide, cuprous oxide, cuprous iodide and cuprous thiocyanate; Preferably, the material of the second carrier transport layer (50) is selected from C 60 , PCBM and 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline; Preferably, the material of the metal electrode layer (60) is selected from one or more of the group consisting of silver, copper and gold.

5. The perovskite solar cell according to claim 4, characterized in that: A cathode buffer layer (70) and a transparent conductive oxide layer (80) are further provided between the second carrier transport layer (50) and the metal electrode layer (60), wherein the cathode buffer layer (70) is provided between the second carrier transport layer (50) and the transparent conductive oxide layer (80), and the transparent conductive oxide layer (80) is provided between the cathode buffer layer (70) and the metal electrode layer (60); Preferably, the thickness of the cathode buffer layer (70) is 10 to 20 nm; Preferably, the thickness of the transparent conductive oxide layer (80) is 5 to 20 nm; Preferably, the material of the cathode buffer layer (70) is selected from one or more of the group consisting of 3,3'-(1,3,8,10-tetraanthraquinone [2,1,9-DEF:6,5,10-D'E'F'] diisoquinoline-2,9 (1H,3H,8H,10H)-diyl) bis (N,N-dimethylpropane-1-amine oxide), ethoxylated polyethyleneimine, poly [3-(6-trimethylammoniumhexyl) thiophene] and tin oxide; Preferably, the material of the transparent conductive oxide layer (80) is selected from indium zinc oxide and / or fluorine-doped tin oxide.

6. A method for preparing a perovskite solar cell according to any one of claims 1 to 5, characterized in that: The preparation method comprises: Step S1, prepare a transparent conductive substrate (10) for standby use; Step S2, preparing a first carrier transport layer (20) on one side of the conductive surface of the transparent conductive substrate (10); Step S3, preparing a perovskite active layer (30) on a surface of the first carrier transport layer (20) that is away from the transparent conductive substrate (10); Step S4, coating a solution containing the compound represented by general formula (I) on a surface of the perovskite active layer (30) away from the first carrier transport layer (20), and obtaining a photo-oxidation protective layer (40) after drying; Step S5, preparing a second carrier transport layer (50) on a surface of the photo-oxidation protection layer (40) away from the perovskite active layer (30); Step S6, preparing a metal electrode layer (60) on the surface of the second carrier transport layer (50) away from the photo-oxidation protection layer (40) to obtain the perovskite solar cell.

7. The method for preparing a perovskite solar cell according to claim 6, characterized in that: The step S4 comprises: mixing the compound represented by the general formula (I) with a solvent to obtain a mixed solution; spin coating or spray coating the mixed solution on a surface of the perovskite active layer (30) away from the first carrier transport layer (20), and drying to obtain the photo-oxidation protective layer (40); Preferably, the mass concentration of the solution containing the compound represented by general formula (I) is 0.1 to 5 mg / mL; Preferably, the coating is performed by spin coating, and preferably the spin coating speed is 3000-6000 rpm and the time is 10-30 s; Preferably, the coating is performed by spraying, and preferably, the distance between the nozzle used in the spraying process and the surface of the side of the perovskite active layer (30) away from the first carrier transport layer (20) is 1 to 3 cm, the pressure is 20 to 100 kPa, and the spray density is 1000 to 5000 g / cm 3 , time is 10~50s; Preferably, the solvent is selected from one or more of the group consisting of dimethylformamide, dimethyl sulfoxide, methanol, ethanol, isopropanol, n-butanol and isooctyl alcohol; Preferably, the drying temperature is 90-180° C. and the drying time is 5-10 min.

8. The method for preparing a perovskite solar cell according to claim 6, characterized in that: The method further includes, between step S5 and step S6: preparing a cathode buffer layer (70) on a surface of the second carrier transport layer (50) away from the photo-oxidation protection layer (40); and preparing a transparent conductive oxide layer (80) on a surface of the cathode buffer layer (70) away from the second carrier transport layer (50). Preferably, the cathode buffer layer (70) is prepared by sputtering; Preferably, the transparent conductive oxide layer (80) is prepared by physical vapor deposition or chemical vapor deposition, and more preferably, the physical vapor deposition method is sputtering.

9. A perovskite / crystalline silicon tandem solar cell, characterized in that: The perovskite / crystalline silicon tandem solar cell comprises the perovskite solar cell according to any one of claims 1 to 5 and a crystalline silicon bottom cell (90).

10. A method for preparing a perovskite / crystalline silicon tandem solar cell according to claim 9, characterized in that: The preparation method comprises: providing a crystalline silicon bottom cell (90), optionally preparing a transparent conductive layer (11) on one side surface of the crystalline silicon bottom cell (90), and sequentially preparing a first carrier transport layer (20), a perovskite active layer (30), a photo-oxidation protective layer (40), a second carrier transport layer (50) and a metal electrode layer (60) on a side surface of the transparent conductive layer (11) away from the crystalline silicon bottom cell (90), wherein the preparation method of the first carrier transport layer (20), the perovskite active layer (30), the photo-oxidation protective layer (40), the second carrier transport layer (50) and the metal electrode layer (60) has the same definition as that of claim 6; the crystalline silicon bottom cell (90) is selected from a HJT cell, a TOPCon cell or an IBC cell; Preferably, the preparation method further comprises: preparing a cathode buffer layer (70) on a surface of the second carrier transport layer (50) away from the photo-oxidation protection layer (40), preferably preparing the cathode buffer layer (70) by sputtering; Preferably, the preparation method further comprises: preparing a transparent conductive oxide layer (80) on a surface of the cathode buffer layer (70) away from the second carrier transport layer (50), preferably using physical vapor deposition or chemical vapor deposition to prepare the transparent conductive oxide layer (80), and more preferably the physical vapor deposition method is sputtering.

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