Perovskite cell and preparation method thereof, laminated cell and photovoltaic module

Abstract

The invention provides a perovskite cell and a preparation method thereof, a laminated cell and a photovoltaic module. The perovskite cell comprises a first transparent conductive layer, a hole transport layer, a perovskite active layer, an electron transport layer, a second transparent conductive layer and a first interface modification layer, the first interface modification layer is arranged between the hole transport layer and the perovskite active layer and comprises graphene oxide and a carbon nanotube, the surface of the graphene oxide is connected with a functional group or lead ions, and the functional group comprises at least one of an amino group, a thiol group and a quaternary ammonium salt group. Therefore, an oxygen-containing functional group of GO can form a coordinate bond or a hydrogen bond with a defect site of the hole transport layer or the perovskite active layer, and non-radiative recombination is inhibited, so that the open-circuit voltage of the perovskite cell is improved; gO can improve the interface wettability problem and improve the subsequent film forming quality; the CNT can construct a high mobility channel, and the GO fills the CNT network gap, thereby being more beneficial to carrier transport, and further improving the fill factor of the perovskite cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a perovskite battery, a preparation method thereof, a stacked battery and a photovoltaic module. BACKGROUND

[0002] The perovskite / crystalline silicon stacked battery is a structure in which a crystalline silicon solar cell and a perovskite solar cell are stacked together, and through complementary advantages and synergistic effects, the conversion efficiency is improved. In the stacked battery, the recombination loss at the interface is the main reason for the voltage loss of the perovskite top cell and the stacked battery, which seriously limits the improvement of the device performance. For example, the hole transport layer NiOx is usually deposited by magnetron sputtering, and the surface defect density is high, and the recombination probability is increased. Although a small molecule self-assembled layer such as 4PACz can be spin-coated on the surface of NiOx to improve the defect condition of the surface of NiOx, the wettability of 4PACz is poor, and it is easy to cause the surface of the perovskite film prepared subsequently to be deposited unevenly. SUMMARY

[0003] The present application aims to at least solve one of the technical problems in the related art. To this end, one object of the present application is to provide a perovskite battery in which the interface defects of the hole transport layer are effectively improved, and the non-radiative recombination is effectively inhibited.

[0004] In one aspect of the present application, a perovskite battery is provided. According to an embodiment of the present application, the perovskite battery includes a first transparent conductive layer, a first charge transport layer, a perovskite active layer, a second charge transport layer, and a second transparent conductive layer, one of the first charge transport layer and the second charge transport layer being a hole transport layer, and the other being an electron transport layer; the perovskite battery further includes a first interface modification layer, the first interface modification layer being disposed between the hole transport layer and the perovskite active layer and including graphene oxide (GO) and carbon nanotubes (CNT), wherein the graphene oxide surface is connected with a functional group or a lead ion, and the functional group includes at least one of an amino group, a thiol group, and a quaternary ammonium salt group. Thus, the oxygen-containing functional groups (such as carboxyl groups and epoxy groups) on the surface of the graphene oxide can be connected to the defect sites (such as uncoordinated Pb x , Spiro-OMeTAD) of the hole transport layer (such as NiO 2+, the suspension key) to form a coordination bond or a hydrogen bond, to inhibit non-radiative recombination, and to further improve the open-circuit voltage (Voc) of the perovskite battery; the oxygen-containing functional groups (such as carboxyl groups) of the GO have hydrophilicity, which can improve the interface wetting problem and improve the subsequent film forming quality; the surface of the graphene oxide is rich in carboxyl and hydroxyl groups, which can bond with lead ions through coordination and orderly and uniformly fix the lead ions on the two-dimensional interface of the graphene oxide, and the lead ions can help to form perovskite crystals with uniform distribution; the grafting of the functional groups can help to improve the adhesion between the hole transport layer and the perovskite active layer and / or regulate the energy level and reduce recombination; the CNT can construct a high-mobility channel, and the GO fills the gap between the CNT network, and the resistance of the first interface modification layer is lower than that of a single-layer GO, which is more conducive to the carrier transport and further improves the fill factor (FF) of the perovskite battery.

[0005] According to an embodiment of the present application, the first interface modification layer further comprises reduced graphene oxide, and the thickness of the first interface modification layer is 5-10 nm.

[0006] According to an embodiment of the present application, the perovskite battery further comprises a second interface modification layer, the second interface modification layer is arranged between the first interface modification layer and the hole transport layer, and the second interface modification layer comprises graphene oxide or comprises graphene oxide and reduced graphene oxide.

[0007] According to an embodiment of the present application, the thickness of the second interface modification layer is 1-4 nm, and / or the surface of the graphene oxide in the second interface modification layer is connected with the functional groups or lead ions.

[0008] In another aspect of the present application, the present application provides a method for preparing the perovskite battery described above. According to an embodiment of the present application, the method for preparing the perovskite battery comprises the steps of preparing a first transparent conductive layer, a first charge transport layer, a perovskite active layer, a second charge transport layer and a second transparent conductive layer, one of the first charge transport layer and the second charge transport layer is a hole transport layer, and the other is an electron transport layer, and the method for preparing the perovskite battery further comprises: forming a first interface modification layer between the hole transport layer and the perovskite active layer, and the method for forming the first interface modification layer comprises: coating a first interface modification liquid containing graphene oxide and carbon nanotubes, and heat treating to obtain the first interface modification layer, wherein the surface of the graphene oxide is connected with functional groups or lead ions, and the functional groups comprise at least one of amino groups, thiol groups and quaternary ammonium salt groups. Thus, the formation of the above-mentioned first interface modification layer, the oxygen-containing functional groups (such as carboxyl groups and epoxy groups) on the surface of the graphene oxide can be combined with the defect sites (such as uncoordinated Pb x , Spiro-OMeTAD) of the hole transport layer or the perovskite active layer, and the graphene oxide can be combined with the defect sites (such as uncoordinated Pb 2+The oxygen-containing functional groups (such as carboxyl) of the GO have hydrophilicity, which can improve the interface wetting problem and improve the subsequent film forming quality. The surface of the graphene oxide is rich in carboxyl and hydroxyl groups, which can bond lead ions through coordination and fix the lead ions orderly and uniformly on the two-dimensional interface of the graphene oxide, and the lead ions can help form a uniformly distributed and orderly perovskite crystal. The grafting of the functional groups can help improve the adhesion between the hole transport layer and the perovskite active layer and / or regulate the energy level, and reduce the recombination. The CNT can construct a high-mobility channel, and the GO fills the gap of the CNT network. The resistance of the first interface modification layer is lower than that of the single-layer GO, which is more conducive to the carrier transport, and thus the fill factor (FF) of the perovskite battery is improved.

[0009] According to an embodiment of the present application, in the first interface modification liquid, the concentration of the graphene oxide is 0.05-0.25 mg / mL, and the concentration of the carbon nanotube is 0.05-0.15 mg / mL, and / or the temperature of the heat treatment is 100-150°C, and the time is 10-30 minutes.

[0010] According to an embodiment of the present application, the method for preparing the perovskite battery further comprises: forming a second interface modification layer between the first interface modification layer and the hole transport layer, and the method for forming the second interface modification layer comprises: coating a second interface modification liquid and annealing to obtain the second interface modification layer.

[0011] According to an embodiment of the present application, the concentration of the graphene oxide in the second interface modification liquid is 0.1-0.5 mg / mL.

[0012] In another aspect of the present application, the present application provides a stacked battery. According to an embodiment of the present application, the stacked battery comprises: a crystalline silicon bottom cell and a perovskite top cell located on the light-receiving surface of the crystalline silicon bottom cell, and the perovskite top cell is the perovskite battery as described above. Thus, the open-circuit voltage (Voc) and the fill factor (FF) of the stacked battery are simultaneously improved, and thus the battery efficiency of the stacked battery is improved.

[0013] In another aspect of the present application, the present application provides a photovoltaic module according to an embodiment of the present application. The photovoltaic module comprises the perovskite battery as described above, or comprises the stacked battery as described above. Thus, the photovoltaic module has a high photoelectric conversion efficiency.

[0014] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0015] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the following drawings of which: Figure 1 is a structural schematic diagram of a perovskite cell in one embodiment of the present application; Figure 2 is a structural schematic diagram of a perovskite cell in another embodiment of the present application. DETAILED DESCRIPTION

[0016] The scheme of the present application will be explained below in conjunction with the embodiments. Those skilled in the art will understand that the following embodiments are only for illustration of the present application and should not be regarded as limiting the scope of the present application. If a specific technique or condition is not specified in the embodiments, the technique or condition described in the literature in the art or according to the product manual is used. If the manufacturer of the reagent or instrument is not specified, it is a conventional product that can be obtained by purchase in the market.

[0017] The present application will be described below with reference to specific embodiments, and it should be noted that these embodiments are merely descriptive and do not limit the present application in any way.

[0018] In one aspect of the present application, the present application provides a perovskite cell. According to embodiments of the present application, the perovskite cell includes: a first transparent conductive layer 11, a first charge transport layer 21, a perovskite active layer 30, a second charge transport layer 22, and a second transparent conductive layer 12, one of the first charge transport layer 21 and the second charge transport layer 22 is a hole transport layer, and the other is an electron transport layer (for example, the first charge transport layer 21 is a hole transport layer in the following embodiment). Figure 1 The perovskite cell further includes: a first interface modification layer 41, the first interface modification layer 41 is disposed between the hole transport layer and the perovskite active layer 30. In some embodiments, referring to Figure 1 , the first charge transport layer 21 is disposed on one side of the first transparent conductive layer 11; the perovskite active layer 30 is disposed on the side of the first charge transport layer 21 away from the first transparent conductive layer 11; the second charge transport layer 22 is disposed on the side of the perovskite active layer 30 away from the first transparent conductive layer 11, one of the first charge transport layer 21 and the second charge transport layer 22 is a hole transport layer, and the other is an electron transport layer; the second transparent conductive layer 12 is disposed on the side of the second charge transport layer 22 away from the first transparent conductive layer 11, and the first interface modification layer 41 is disposed between the hole transport layer and the perovskite active layer 30.

[0019] According to an embodiment of the present application, the first interface modification layer 41 comprises graphene oxide (GO) and carbon nanotubes (CNT), wherein the graphene oxide surface is connected with functional groups or lead ions, and the functional groups comprise at least one of amino groups, thiol groups and quaternary ammonium salt groups. The oxygen-containing functional groups (such as carboxyl groups and epoxy groups) on the surface of the graphene oxide (GO) can form coordination bonds or hydrogen bonds with the defect sites (such as uncoordinated Pb x 2+ , and dangling bonds) of the hole transport layer (such as NiOSpiro-OMeTAD) or the perovskite active layer, inhibit non-radiative recombination, and thus improve the open-circuit voltage (Voc) of the perovskite battery; the oxygen-containing functional groups (such as carboxyl groups) of the GO have hydrophilicity, which can improve the interface wetting problem and improve the subsequent film forming quality; the graphene oxide surface is rich in carboxyl and hydroxyl groups, which can adsorb lead ions through coordination, and orderly and uniformly fix the lead ions on the two-dimensional interface of the graphene oxide, and the lead ions can help to form uniformly distributed and ordered perovskite crystals; the grafting of the functional groups can help to improve the adhesion between the hole transport layer and the perovskite active layer and / or regulate the energy level, and reduce recombination; the CNT can construct a high-mobility channel, and the GO fills the gap between the CNT network, and the resistance of the first interface modification layer is lower than that of a single-layer GO, which is more conducive to carrier transport, and thus improves the fill factor (FF) of the perovskite battery.

[0020] The graphene oxide (GO) has good hydrophilicity, which is conducive to perovskite nucleation and growth, and is rich in oxygen-containing functional groups (-COOH, -OH), which can effectively passivate the defects on the surface of NiOx, but the conductivity of GO is poor, which will increase the series resistance, and the excessive hydrophilicity may affect the long-term stability of the device. The conductivity of CNT is excellent, which is conducive to hole extraction and transport, and its one-dimensional structure can provide a charge transport channel. However, CNT is prone to aggregation, has poor dispersibility in solvents, and has weak defect passivation ability for the hole transport layer (such as NiOx), and is itself hydrophobic, which will exacerbate the perovskite film forming problem. In the present application, the interface modification layer comprises graphene oxide and carbon nanotubes, and GO and CNT not only make up for each other's shortcomings, but also better improve the performance of the battery, as follows: First, the oxygen-containing functional groups of GO as a defect repair agent can grab uncoordinated ions (such as Pb 2+ , I -), greatly reducing the interface defect state density, and inhibiting non-radiative recombination. The holes separated from the interface passivated by GO can be quickly captured by CNT and efficiently transported to the hole transport layer, that is, GO solves the problem of weak passivation ability of CNT, and CNT solves the problem of poor conductivity of GO, and further, the setting of the first interface modification layer in the present application can significantly improve the open-circuit voltage (Voc) and fill factor (FF) of the perovskite battery at the same time (the Voc improvement is due to the reduction of recombination, and the FF improvement is due to the reduction of series resistance and the improvement of charge collection efficiency).

[0021] Secondly, GO has a two-dimensional sheet structure, although it can provide surface passivation and certain energy level regulation, but it is easy to stack and form an insulating area that hinders charge transport; CNT has a one-dimensional tubular structure, has strong conductivity, but poor dispersibility, is easy to agglomerate, and is difficult to form a complete and uniform film. The first interface modification layer in the present application combines GO with CNT, CNT can act as a supporting skeleton, can prevent excessive stacking between GO sheets, maintain the dispersibility of GO layers, and at the same time, the oxygen functional groups of GO can improve the dispersibility and wettability of CNT, so that the composite film can not only maintain continuous coverage, but also provide a conductive channel. In this way, the first interface modification layer not only avoids the problem of insulating GO, but also solves the problems of poor dispersibility and uneven film formation of CNT, forming a stable, uniform and conductive interface layer.

[0022] Thirdly, GO has oxygen functional groups on the surface, which can adjust the work function, so that the energy level of the hole transport layer (such as NiOx) and the perovskite layer is more matched, and CNT has high conductivity and relatively stable work function. Therefore, when the two are combined, the energy level regulation of GO and the conductivity of CNT combine to make the overall work function of the first interface modification layer closer to the valence band of the perovskite, while reducing the interface barrier. In this way, the first interface modification layer not only improves the energy level matching, but also reduces the energy loss of charge injection, and improves the open-circuit voltage (Voc).

[0023] Fourthly, the carboxyl groups (-COOH) and hydroxyl groups (-OH) on the surface of GO can firmly grasp Pb 2+ and I⁻ ions through coordination, and orderly and uniformly fix them on the two-dimensional plane of GO. These pre-anchored Pb 2+ become the "seeds" of B-site ions in the perovskite crystal (general formula ABX3). When the perovskite precursor solution is coated, the I⁻ and organic ammonium ions (A-site, such as MA⁺ and FA⁺) in the solution will spontaneously arrange around these already fixed "seeds" to form the crystal nucleus of perovskite. Since the "seeds" are uniformly distributed, the nucleation points are more and more uniform, avoiding excessive crowding of subsequent grains to compete for raw materials, so that it is easier to form large-size and uniformly oriented perovskite grains.

[0024] Further, the graphene oxide surface is grafted with amino (GO-NH2), the electron-donating effect of the amino can improve the Fermi level of GO and reduce its work function, which makes the energy level of GO-NH2 more match the valence band top of the p-type material (such as NiOx), and is conducive to the extraction and transmission of holes from the perovskite layer to the hole transport layer, and reduces the interface recombination loss; the graphene oxide surface is grafted with thiol (GO-SH), which can not only enhance the interface bonding, but also passivate the hole transport material (such as NiOx) or the metal atom related defects (such as nickel vacancies, lead vacancies or iodine vacancies) on the perovskite surface, and reduce the interface state density. Further, it is helpful to inhibit the non-radiative recombination of charges at the interface and improve the open-circuit voltage of the device; the graphene oxide surface is grafted with quaternary ammonium salt groups (covalently bonded quaternary ammonium salt GO, which can be referred to as QGO), the quaternary ammonium salt group has a strong electron-withdrawing induction effect (-I effect), which can reduce the work function of GO, shift the conduction band and valence band levels of GO, and further realize fine control of the energy level and optimal energy band alignment with the adjacent layer.

[0025] As can be seen from the above, in the first interface modification layer of the present application, the modification of GO and CNT is not only the superposition of the action of the two, but also a synergistic effect: CNT inhibits the stacking of GO layer and provides a fast charge transmission channel, and GO improves the dispersibility of CNT and passivates the surface defects of NiOx, and the two work together to make the interface layer have excellent film uniformity, defect passivation ability, energy level matching and carrier transmission efficiency. This synergistic effect not only reduces the interface recombination loss, but also significantly improves the crystalline quality of the perovskite film and the photoelectric conversion efficiency and stability of the device, which cannot be achieved by using GO or CNT alone.

[0026] According to some embodiments of the present application, the first interface modification layer further comprises reduced graphene oxide. Thus, part of the graphene oxide GO is partially reduced to reduced graphene oxide, which improves the conductivity of graphene and enhances the π-π interaction between GO and CNT, and better improves the interface contact.

[0027] According to some embodiments of the present application, the thickness of the first interface modification layer is 5-10 nm, such as 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc. Thus, the first interface modification layer has good adhesion and is in the range of improving the interface contact, and the above thickness is easy to prepare in process and has better thickness uniformity; if the thickness is too large, the overall resistivity of the first interface modification layer may be too large, and the optical loss is also large.

[0028] According to some embodiments of the present application, referring to Figure 2The perovskite cell further comprises a second interface modification layer 42, which is arranged between the first interface modification layer 41 and the hole transport layer (taking the first charge transport layer 21 as an example), and the second interface modification layer 42 comprises graphene oxide or comprises graphene oxide and reduced graphene oxide. In this way, the arrangement of the second interface modification layer can further improve the passivation effect on the hole transport layer and better improve the interface defects.

[0029] According to some embodiments of the present application, the thickness of the second interface modification layer is 1-4 nm, such as 1 nm, 2 nm, 3 nm or 4 nm, etc. In this way, the second interface modification layer with the above thickness can better ensure that the charges can tunnel and passivate the hole transport layer, and the second interface modification layer that is too thick can hinder the charge transport and increase the series resistance.

[0030] According to some embodiments of the present application, the surface of the graphene oxide in the second interface modification layer is connected with a functional group or coordinated with a lead ion, and the functional group includes at least one of the above-mentioned amino group, thiol group and quaternary ammonium salt group.

[0031] According to some embodiments of the present application, the material of the first transparent conductive layer and the second transparent conductive layer includes but is not limited to transparent conductive materials such as ITO and IZO. The thickness of the first transparent conductive layer can be 5-10 nm, and the thickness of the second transparent conductive layer can be 30-100 nm.

[0032] According to some embodiments of the present application, the material structure of the perovskite active layer can be ABX3, wherein A is a monovalent cation, including but not limited to one or more monovalent cation mixtures of cesium (Cs), rubidium (Rb), methylamine group (CH3NH3), formamidine group (CH2(NH2)2); B is a divalent cation, including but not limited to one or more divalent cation mixtures of lead (Pb), tin (Sn), X is a monovalent anion, including but not limited to one or more monovalent anion mixtures of iodine (I), bromine (Br), chlorine (Cl), fluorine (F), thiocyanate ion (SCN).

[0033] According to some embodiments of the present application, the material of the hole transport layer includes nickel oxide (NiO xCuSCN, 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), 2,2',7,7'-tetrakis(di-p-tolylamino)spiro-9,9'-bifluorene (Spiro-TTB), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), and [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl]phosphonic acid (MeO-4PACz), (4-(3,6-dimethyl-9H-carbazol-9-yl)butyl)phosphonic acid (Me-4PACz), [4-(9H-carbazol-9-yl)butyl]phosphonic acid (4PACz), (4-(3,6-dibromo-9H-carbazol-9-yl)butyl)phosphonic acid (Br-4PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), (2-(3,6-dimethyl-9H-carbazol-9-yl)ethyl)phosphonic acid (Me-2PACz), (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz), (2-(3,6-dibromo-9H-carbazol-9-yl)ethyl)phosphonic acid (Br-2PACz), and the like. In some embodiments, the material of the hole transport layer is nickel oxide, and thus the improvement on the performance of the battery is better. The thickness can be 5-30 nm.

[0034] According to some embodiments of the present application, the electron transport material of the electron transport layer includes, but is not limited to, tin oxide, fullerene and its derivatives, imide compounds, quinone compounds, and the like. Exemplarily, the imide compounds include at least one of phthalimide, succinimide, N-bromosuccinimide, glutarimide or maleimide; exemplarily, the quinone compounds include at least one of benzoquinone, naphthoquinone, phenanthraquinone or anthraquinone; exemplarily, the fullerene and its derivatives include at least one of fullerene C 60 , fullerene C 70 , PCBM ([6,6]-phenyl-C 61 butyric acid methyl ester), [6,6]-phenyl-C 71 butyric acid methyl ester (PC 71 BM). Further, the electron transport layer can be a single-layer structure, or a double-layer or triple-layer structure. In some embodiments, the electron transport layer can include a C60 layer with a thickness of 5-20 nm and a tin oxide layer with a thickness of 15-20 nm, and the tin oxide layer can be arranged to protect the C60 in subsequent processes. In some embodiments, the thickness of the C60 layer can be 5-20 nm, and the thickness of the tin oxide layer can be 10-30 nm.

[0035] In another aspect of the present application, the present application provides a method for preparing the perovskite cell described above. According to an embodiment of the present application, the method for preparing the perovskite cell comprises the steps of preparing a first transparent conductive layer, a first charge transport layer, a perovskite active layer, a second charge transport layer and a second transparent conductive layer, one of the first charge transport layer and the second charge transport layer being a hole transport layer and the other being an electron transport layer, and the method for preparing the perovskite cell further comprises: forming a first interface modification layer between the hole transport layer and the perovskite active layer, and the method for forming the first interface modification layer comprises: coating a first interface modification solution containing graphene oxide and carbon nanotubes, and heat treating to obtain the first interface modification layer, wherein the graphene oxide has a functional group or a lead ion connected to the surface of the graphene oxide, and the functional group comprises at least one of an amino group, a thiol group and a quaternary ammonium salt group.

[0036] According to some embodiments of the present application, the concentration of the graphene oxide in the first interface modification solution is 0.05-0.25 mg / mL, such as 0.05 mg / mL, 0.08 mg / mL, 0.1 mg / mL, 0.12 mg / mL, 0.15 mg / mL, 0.18 mg / mL, 0.2 mg / mL, 0.23 mg / mL, 0.25 mg / mL, etc., and the concentration of the carbon nanotubes in the first interface modification solution is 0.05-0.15 mg / mL, such as 0.05 mg / mL, 0.06 mg / mL, 0.07 mg / mL, 0.08 mg / mL, 0.09 mg / mL, 0.1 mg / mL, 0.11 mg / mL, 0.12 mg / mL, 0.13 mg / mL, 0.14 mg / mL, 0.15 mg / mL, etc. In this way, the graphene oxide and the carbon nanotubes can be uniformly dispersed without aggregation, which is conducive to preparing a first interface modification layer with uniform thickness and uniform dispersion. If the concentration of the graphene oxide or the carbon nanotubes is too high, it is relatively difficult to prepare a fine interface modification film. If the concentration of the graphene oxide or the carbon nanotubes is too low, it is easy to cause the modification layer to be discontinuous.

[0037] According to some embodiments of the present application, the heat treatment is performed at a temperature of 100-150°C, such as 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc., for a time of 10-30 minutes, such as 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, etc. In this way, the residual solvent can be effectively evaporated and removed, the adhesion can be improved, and at the same time, the GO is prevented from being excessively reduced or the perovskite active layer or the hole transport layer is prevented from being damaged for a long time at a high temperature.

[0038] According to some embodiments of the present application, the method for preparing the perovskite cell further comprises: forming a second interface modification layer between the first interface modification layer and the hole transport layer, and the method for forming the second interface modification layer comprises: coating a second interface modification liquid, and annealing to obtain the second interface modification layer.

[0039] According to some embodiments of the present application, the concentration of graphene oxide in the second interface modification liquid is 0.1-0.5 mg / mL, such as 0.1 mg / mL, 0.15 mg / mL, 0.2 mg / mL, 0.25 mg / mL, 0.30 mg / mL, 0.35 mg / mL, 0.4 mg / mL, 0.45 mg / mL, 0.50 mg / mL, etc. In this way, the graphene oxide can be uniformly dispersed without aggregation, which is conducive to preparing the second interface modification layer with uniform thickness and uniform dispersion. In some embodiments, the annealing temperature can be 100-150°C, and the time can be 10-30 minutes.

[0040] According to some embodiments of the present application, the surface of the graphene oxide in the second interface modification liquid is connected with a functional group or coordinated with lead ions, and the functional group includes at least one of the above-mentioned amino group, thiol group and quaternary ammonium salt group.

[0041] According to some embodiments of the present application, the method for coordinating lead ions on the surface of graphene oxide comprises: mixing a mixed liquid containing graphene oxide and carbon nanotubes with a lead salt (such as lead nitrate) solution under pH adjustment of 5-7 for a certain time, and the functional groups on the surface of GO fix Pb 2+ by ion exchange or coordination. After the reaction is completed, the solid product is collected by centrifugation or filtration (such as vacuum filtration), and repeatedly washed with deionized water for several times to remove physically adsorbed, unbound free Pb 2 + . Finally, the product is redispersed in a solvent or dried into a solid for standby. The concentration of the lead salt solution, the reaction temperature and time are not limited, and can be designed flexibly by those skilled in the art according to requirements.

[0042] According to some embodiments of the present application, the principle of grafting amino groups (GO-NH2) on the surface of graphene oxide (GO): the surface of graphene oxide (GO) is rich in active oxygen-containing functional groups such as epoxy groups (-O-), carboxyl groups (-COOH), and hydroxyl groups (-OH). These sites are used to chemically react with compounds containing amino groups (such as ethylenediamine or ethylenediamine hydrochloride), thereby grafting amino groups onto GO. In some embodiments, the hydrothermal method can be used for amination, which includes: first, dispersing GO in a solvent (such as water), adding excess ethylenediamine (or ethylenediamine hydrochloride), and stirring to mix uniformly; then, transferring the mixed solution to a high-pressure reaction kettle lined with polytetrafluoroethylene, and placing the reaction kettle in an oven for heating (temperature range 120-180°C) for several hours to several dozen hours; finally, after the reaction is completed, naturally cooling to room temperature, and dialysis or repeated centrifugal washing of the product to remove unreacted amine compounds and byproducts, thereby obtaining aminated graphene oxide (GO-NH2).

[0043] According to some embodiments of the present application, the principle of grafting thiol groups (GO-SH) on the surface of graphene oxide (GO): thiolation is mainly achieved by chemical reaction between the inherent oxygen-containing functional groups (such as carboxyl and epoxy groups) on the surface of GO and compounds containing sulfhydryl groups (-SH) (such as cysteamine). The core of the preparation method is to activate the carboxyl groups on GO, so that they can more easily undergo amidation reaction with thiol molecules containing amino groups. The specific method can include: step one (acylchlorination of GO): ① dispersing dry GO powder in anhydrous tetrahydrofuran (THF) and ultrasonically treating to obtain a uniform dispersion; ② under ice water bath cooling and magnetic stirring, slowly adding excess SOCl2 dropwise to the dispersion (for example, the mass-volume ratio of GO to SOCl2 can be 1 g: 50 mL); ③ after the dropwise addition is completed, remove the ice bath, heat the mixture under reflux condensation device (such as 65°C) and continue to stir for 24 hours; ④ after the reaction is completed, remove the excess SOCl2 and solvent by distillation under reduced pressure to obtain acylchlorinated GO (GO-COCl). Step two (amidation reaction to introduce -SH): ① redispersed GO-COCl obtained in the above step in anhydrous THF or N,N-dimethylformamide (DMF); ② add excess cysteamine (for example, the molar ratio of GO to cysteamine can be more than 1:100 to ensure sufficient reaction); ③ under nitrogen protection, stir at room temperature or slightly heated (such as 50-60°C) for 24-48 hours; ④ after the reaction is completed, remove the unreacted cysteamine and byproducts by repeated centrifugation and washing (using ethanol / water mixed solvent or pure water) until the supernatant has no -SH characteristic color (purple) detected by sodium nitroprusside; ⑤ the final product (thiolated GO, GO-SH) can be dispersed in water or dried for storage.

[0044] According to some embodiments of the present application, the principle of grafting quaternary ammonium salt groups on the surface of graphene oxide: quaternary ammonium salt molecules can be directly grafted onto the skeleton of GO by covalent bonding method, forming stable chemical bonds to realize quaternary ammonium salt. For example, epoxy group ring-opening reaction, using a large number of epoxy groups (-CH(O)CH-) on the GO sheet layer to react with tertiary amine molecules to form alcohol amine structure with quaternary ammonium groups. The specific method can include: ① mixing GO dispersion liquid with excess tertiary amine containing compounds (such as N,N-dimethyl ethylenediamine (DMEDA), tris(2-aminoethyl)amine (TAEA)); ②stirring and reflux condensing the reaction mixture at 70-90°C for 12-48 hours, the reaction mechanism (nucleophilic ring-opening reaction): the nitrogen atom (with lone pair of electrons) in the tertiary amine group acts as a nucleophile to attack the carbon atom on the GO epoxy group, leading to ring-opening of the epoxy ring, and finally forming a β-hydroxyl quaternary ammonium salt structure; ③after the reaction is completed, dialysis (for water system) or repeated centrifugal washing (using water / ethanol mixed solvent) is used to completely remove unreacted amine compounds and by-products, and finally covalently bonded quaternary ammonium salt GO (QGO) is obtained.

[0045] According to some embodiments of the present application, the method for preparing a perovskite battery comprises: S1: preparing a hole transport layer on one side surface of a first transparent conductive layer by a magnetron sputtering or coating method (for example, depositing nickel oxide as a hole transport layer by magnetron sputtering).

[0046] S2: ultrasonically dispersing graphene oxide connected with lead ions or functional groups in a solvent (such as water and / or ethanol) to obtain a GO dispersion liquid with a concentration of 0.1-0.5 mg / mL; ultrasonically dispersing semiconductor single-walled CNT in a dispersant (such as SDBS) to obtain a CNT dispersion liquid with a concentration of 0.1-0.3 mg / mL; mixing and ultrasonically treating the GO dispersion liquid and the CNT dispersion liquid according to a specific volume ratio (such as 1:1) to obtain a first interface modification liquid.

[0047] S3: spin coating an ultrathin GO dispersion liquid (the GO in the GP dispersion liquid can be unmodified GO or modified GO, i.e., graphene oxide connected with lead ions or functional groups) on the surface of the hole transport layer at a rotation speed of 2000 rpm for 15-30 s, and annealing to obtain a second interface modification layer; S4: spin coating the first interface modification liquid on the surface of the second interface modification layer at a rotation speed of 3000 rpm for 25-60 s, and heat treating the thin film after spin coating in an inert atmosphere or air at a temperature of 100-150°C for 10-30 minutes to obtain a first interface modification layer.

[0048] S5: Spin-coat the perovskite precursor solution onto the surface of the first interface modification layer, first at 2500 rpm for 10 s, then at 3500 rpm for 25 s; 5 s before the end of the spin-coating process, drop 200 μL of chlorobenzene into the center of the substrate. After the spin-coating stops, immediately transfer the substrate to a heating plate at 100°C and anneal for 15-20 min to obtain a perovskite active layer with a thickness of 500-900 nm.

[0049] S6: A C60 layer with a thickness of 5-20 nm is prepared on the surface of the perovskite active layer by thermal evaporation, and then a SnO2 layer with a thickness of 10-30 nm is prepared by atomic layer deposition to obtain an electron transport layer.

[0050] S7: A second transparent conductive layer is deposited on one side of the electron transport layer using a sputtering method.

[0051] S8: An Ag electrode with a thickness of 50-120 nm is deposited on the surface of the transparent conductive layer using a second thermal evaporation method.

[0052] S9: Deposit an anti-reflection layer with a thickness of 50-100 nm on the side of the battery surface furthest from the second transparent conductive layer using a thermal evaporation method (the material can be MgF2).

[0053] According to an embodiment of the present invention, in the formation of the first interface modification layer, the oxygen-containing functional groups (such as carboxyl groups, epoxy groups) on the surface of graphene oxide can interact with the hole transport layer (such as NiO). x Spiro-OMeTAD) or defect sites in the perovskite active layer (such as uncoordinated Pb) 2+ GO forms coordination bonds or hydrogen bonds (such as dangling bonds) to suppress nonradiative recombination, thereby increasing the open-circuit voltage (Voc) of perovskite solar cells. The oxygen-containing functional groups (such as carboxyl groups) of GO are hydrophilic, which can improve the interface wettability problem and improve the quality of subsequent film formation. CNTs can construct high-mobility channels. GO fills the gaps in the CNT network. The resistance of this first interface modification layer is lower than that of monolayer GO, which is more conducive to carrier transport and thus improves the fill factor (FF) of perovskite solar cells.

[0054] In another aspect, the present invention provides a tandem solar cell. According to an embodiment of the present invention, the tandem solar cell includes: a crystalline silicon bottom cell and a perovskite top cell located on the light-receiving surface of the crystalline silicon bottom cell, wherein the perovskite top cell is the perovskite cell described above. Thus, the open-circuit voltage (Voc) and fill factor (FF) of the tandem solar cell are significantly improved simultaneously, thereby improving the cell efficiency of the tandem solar cell.

[0055] According to embodiments of the present application, the specific type of the crystalline silicon bottom cell is not subject to any limitation requirement, and a person skilled in the art can flexibly select it according to actual needs. In some embodiments, the crystalline silicon bottom cell can be a TOPCon cell, a BC cell (such as a TBC cell, an HBC cell, or a hybrid BC cell), or the like.

[0056] According to embodiments of the present application, the first transparent conductive layer can be a composite layer between the crystalline silicon bottom cell and the perovskite top cell.

[0057] In yet another aspect of the present application, the present application provides a photovoltaic module according to embodiments of the present application. The photovoltaic module includes the perovskite cell described above, or includes the stacked cell described above. Thus, the photovoltaic module has a higher photoelectric conversion efficiency.

[0058] Embodiments Embodiment 1 Step 1, polishing the silicon wafer with sodium hydroxide lye.

[0059] Step 2, using the LPCVD deposition method to sequentially deposit a first tunneling layer with a thickness of 2.1 nm and a first polysilicon layer with a thickness of 300 nm on the back surface of the silicon wafer, wherein the deposition conditions of the first tunneling layer are: oxygen flow rate is 30000 sccm, temperature is 600℃, process time is 1000s, and tube soaking is 500s; the deposition conditions of the first polysilicon layer are: deposition temperature is 550℃, process time is 11100s, and the silane flow rates of the three-stage gas inlet mode are 190sccm, 440sccm, and 620sccm, respectively.

[0060] Step 3, boron diffusion of the first polysilicon layer: boron source is boron trichloride, boron source flow rate is 250sccm, temperature is 855℃, process time is 1000s; push temperature is 950℃, process time is 1100s; oxidation temperature is 950℃, oxygen flow rate is 8000sccm, and oxidation time is 1600s, finally forming a boron-doped polysilicon layer + borosilicate glass (BSG) structure, and a PN junction is formed between the boron-doped polysilicon layer and the n-type substrate silicon wafer, wherein the surface concentration of the boron-doped polysilicon layer is 6.4x10^19cm -3 , the BSG thickness is 50nm, and the sheet resistance of the boron-doped polysilicon layer is 80.

[0061] Step 4, removing the BSG formed by the etching on the front surface and the side surface by a wet chain-type machine (HF solution).

[0062] Step 5, removing the boron-doped polysilicon layer on the front and side surfaces by alkali washing through a wet tank-type machine.

[0063] Step 6, a second tunnel layer with a thickness of 2.1 nm and a second polysilicon layer with a thickness of 235 nm are sequentially deposited on the back surface of the silicon wafer by LPCVD deposition method, wherein the deposition conditions of the second tunnel layer are: oxygen flow rate is 30000sccm, temperature is 600℃, process time is 1000s, and tube soaking time is 500s; the deposition conditions of the second polysilicon layer are: deposition temperature is 600℃, process time is 3000s, and the silane flow rates in the three-stage gas feeding mode are 190sccm, 440sccm and 620sccm respectively.

[0064] Step 7, phosphorus diffusion is performed on the second polysilicon layer: phosphorus source is phosphorus pentachloride, the phosphorus source flow rate is 1200sccm, the temperature is 810℃, the process time is 1200s; the push temperature is 880℃, the process time is 1100s; the oxidation temperature is 870℃, the oxygen flow rate is 2100sccm, and the oxidation time is 820s, finally forming a phosphorus-doped polysilicon layer + phosphosilicate glass (PSG) structure, wherein the surface concentration of the boron-doped polysilicon layer is 5.7×10^20cm -3 , the PSG thickness is 50nm, and the sheet resistance of the phosphorus-doped polysilicon layer is 20.

[0065] Step 8, the PSG is removed by wet chain machine (HF solution) to form a wrap-around PSG on the back surface and the side surface.

[0066] Step 9, the phosphorus-doped polysilicon layer wrap-plated on the back surface and the back BSG and the front PSG are removed by wet alkali tank and acid tank respectively.

[0067] Step 10, an aluminum oxide passivation layer is deposited by back-to-back double-insertion method by ALD deposition method, the ALD process temperature is 300℃, the process time is 900s, and the thickness of the passivation layer is 4.3nm.

[0068] Step 11, a anti-reflective film is deposited, the film deposition process temperature is 530℃, and the film is divided into 3 layers, in the direction away from the silicon wafer, the deposition sequence is silicon nitride 1, silicon nitride 2, and silicon nitride 3 in turn, the thickness of the 3 layers is between 28nm, 29nm and 30nm respectively, and the overall thickness of the film is 87nm, and the refractive index is 2.12.

[0069] Step 12, a silver metal grid line, i.e. a back electrode, is formed on the back surface by screen printing method, an ohmic contact is formed between the sintered metal and the boron-doped polysilicon layer by high-temperature sintering, the current is collected and led out, the sintering peak temperature is 710℃, and thus a TBC bottom cell is obtained.

[0070] Step 13, an ITO conductive layer, i.e. a first transparent conductive layer, is deposited on the upper surface of the crystalline silicon bottom cell (i.e. on the surface of the n-type doped polysilicon layer) by magnetron sputtering method, and the thickness is 7nm.

[0071] Step 14, a hole transport layer is prepared on the side surface of the first transparent conductive layer away from the crystalline silicon bottom cell by magnetron sputtering, and the material of the hole transport layer is NiOx, and the thickness of the hole transport layer is 20 nm.

[0072] Step 15, ultrasonic dispersion of graphene oxide connected with lead ions in a mixed solvent of water and ethanol to obtain a first GO dispersion liquid with a concentration of 0.25 mg / mL; ultrasonic dispersion of unmodified graphene oxide in a mixed solvent of water and ethanol to obtain a second GO dispersion liquid with a concentration of 0.25 mg / mL; ultrasonic dispersion of semiconductor single-walled CNT in a solvent with the aid of a dispersant (SDBS) to obtain a CNT dispersion liquid with a concentration of 0.2 mg / mL; mixing and ultrasonic of the first GO dispersion liquid and the CNT dispersion liquid according to a volume ratio of 1:1 to obtain a first interface modification liquid.

[0073] Step 16, spin coating of an ultrathin second GO dispersion liquid on the surface of the NiOx layer at a speed of 2000 rpm for 23 s, and annealing at 120°C to obtain a second interface modification layer with a thickness of 4 nm.

[0074] Step 17, spin coating of the first interface modification liquid on the surface of the second interface modification layer at a speed of 3000 rpm for 45 s, and heat treatment of the thin film after spin coating in an inert atmosphere at a temperature of 120°C for 15 minutes to obtain a first interface modification layer with a thickness of 7 nm.

[0075] Step 18, dispersing PbI2, PbBr2, CsI, FAI and MABr in a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 5:1) to obtain a perovskite precursor solution, and using a spin coating method to prepare a perovskite active layer on the side surface of the first interface modification layer prepared in step 17 away from the NiOx layer: first spin coating at a speed of 2500 rpm for 10 s, and then spin coating at a speed of 3500 rpm for 25 s; 5 s before the end of the spin coating process, 200 μL of chlorobenzene is dropped into the center of the substrate, and after the spin coating is stopped, the substrate is immediately transferred to a heating plate at 100°C and annealed for 18 min to obtain a perovskite active layer Cs 0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3.

[0076] Step 19, a C60 layer with a thickness of 15 nm is prepared on the side surface of the perovskite active layer away from the NiOx layer by a thermal evaporation method; and a SnO2 layer with a thickness of 20 nm is prepared on the surface of the prepared C60 layer by an atomic layer deposition method.

[0077] Step 20, a layer of ITO transparent conductive layer with a thickness of 60 nm is deposited on one side of the SnO2 layer by sputtering method.

[0078] Step 21, an Ag electrode with a thickness of 80 nm is deposited on the surface of the transparent conductive layer by thermal evaporation method.

[0079] Step 22, a MgF2 anti-reflection layer with a thickness of 80 nm is deposited on the farthest side of the first transparent conductive layer of the cell surface by thermal evaporation method, thereby obtaining a crystalline silicon-perovskite stacked cell.

[0080] Example 2 The steps for preparing the stacked cell in Example 1 are basically the same, except that Step 16 for preparing the second interface modification layer is not included, i.e., after Step 15, Step 17 is directly performed, i.e., the first interface modification liquid is spin-coated on the surface of the NiOx layer at a speed of 3000 rpm for 45 s, and the thin film after spin-coating is heat-treated in an inert atmosphere, at a temperature of 120°C for 15 minutes, to obtain the first interface modification layer.

[0081] Example 3 The steps for preparing the stacked cell in Example 1 are basically the same, except that in Step 15, graphene oxide with surface grafted amino groups (GO-NH2) is ultrasonically dispersed in a mixed solvent of water and ethanol to obtain a first GO dispersion liquid with a concentration of 0.25 mg / mL; semiconductive single-walled CNT is ultrasonically dispersed in a solvent with the aid of a dispersing agent (SDBS) to obtain a CNT dispersion liquid with a concentration of 0.2 mg / mL; the first GO dispersion liquid and the CNT dispersion liquid are mixed and ultrasonically treated in a volume ratio of 1:1 to obtain the first interface modification liquid.

[0082] Example 4 The steps for preparing the stacked cell in Example 1 are basically the same, except that in Step 15, graphene oxide with surface grafted thiol groups (GO-SH) is ultrasonically dispersed in a mixed solvent of water and ethanol to obtain a first GO dispersion liquid with a concentration of 0.25 mg / mL; semiconductive single-walled CNT is ultrasonically dispersed in a solvent with the aid of a dispersing agent (SDBS) to obtain a CNT dispersion liquid with a concentration of 0.2 mg / mL; the first GO dispersion liquid and the CNT dispersion liquid are mixed and ultrasonically treated in a volume ratio of 1:1 to obtain the first interface modification liquid.

[0083] Example 5 The steps for preparing the stacked battery in Example 1 are basically the same, except that: step 15, graphene oxide (QGO) grafted with quaternary ammonium salt groups is ultrasonically dispersed in a mixed solvent of water and ethanol to obtain a first GO dispersion liquid with a concentration of 0.25 mg / mL; semiconductive single-walled CNTs are ultrasonically dispersed in a solvent with the assistance of a dispersant (SDBS) to obtain a CNT dispersion liquid with a concentration of 0.2 mg / mL; the first GO dispersion liquid and the CNT dispersion liquid are mixed in a volume ratio of 1:1 and ultrasonically treated to obtain a first interface modification liquid.

[0084] Comparative Example 1 Compared with the steps for preparing the stacked battery in Example 1, the difference is that steps 15 to 17 for preparing the first interface modification layer and the second interface modification layer are not included, i.e., the perovskite active layer is directly formed on the surface of the Eu hole transport layer NiOx.

[0085] Comparative Example 2 Compared with the steps for preparing the stacked battery in Example 1, the difference is that only the second interface modification layer is formed between the NiOx layer and the perovskite light-absorbing layer, and the first interface modification layer is not prepared, but the graphene oxide in the second interface modification layer is coordinated with lead ions, i.e.: Step 15, graphene oxide coordinated with lead ions is ultrasonically dispersed in a mixed solvent of water and ethanol to obtain a second GO dispersion liquid with a concentration of 0.25 mg / mL.

[0086] Step 16, the surface of the NiOx layer is spin-coated with the ultra-thin GO dispersion liquid at a speed of 2000 rpm for 23 s, and the second interface modification layer is obtained by annealing at 120°C, with a thickness of 4 nm.

[0087] Then, the perovskite active layer Cs 0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3 is directly prepared on the surface of the second interface modification layer, and the subsequent steps are the same as in Example 1.

[0088] Comparative Example 3 Compared with the steps for preparing the stacked battery in Example 1, the difference is that only the CNT interface modification layer is formed between the NiOx layer and the perovskite light-absorbing layer, and the first interface modification layer and the second interface modification layer are not prepared, i.e.: Step 15, semiconductive single-walled CNTs are ultrasonically dispersed in a solvent with the assistance of a dispersant (SDBS) to obtain a CNT dispersion liquid with a concentration of 0.2 mg / mL.

[0089] Step 16, the surface of the NiOx layer is spin-coated with the CNT dispersion liquid at a speed of 2000 rpm for 25 s, and the CNT interface modification layer is obtained by annealing at 120°C, with a thickness of 5 nm.

[0090] Then the perovskite active layer Cs 0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3 is prepared directly on the surface of the CNT interface modification layer, and the subsequent steps are the same as in Example 1.

[0091] Comparative Example 4 Compared with the steps for preparing the stacked cell in Example 3, the difference lies in that a second interface modification layer and a CNT interface modification layer are sequentially prepared on the surface of the NiOx layer, but the graphene oxide in the second interface modification layer has amino groups connected to the surface, that is: Step 15, ultrasonic dispersion of graphene oxide with surface grafted amino groups (GO-NH2) in a mixed solvent of water and ethanol to obtain a second GO dispersion liquid with a concentration of 0.25 mg / mL; ultrasonic dispersion of semiconductive single-walled CNT in a solvent with the aid of dispersant (SDBS) to obtain a CNT dispersion liquid with a concentration of 0.2 mg / mL.

[0092] Step 16, spin coating of the ultrathin second GO dispersion liquid on the surface of the NiOx layer at a speed of 2000 rpm for 23 s, and annealing at 120°C to obtain a second interface modification layer with a thickness of 4 nm.

[0093] Step 17, spin coating of the CNT dispersion liquid on the surface of the second interface modification layer at a speed of 2000 rpm for 25 s, and heat treatment of the thin film after spin coating in an inert atmosphere at a temperature of 120°C for 15 minutes to obtain a CNT interface modification layer with a thickness of 5 nm.

[0094] Then the perovskite active layer Cs 0.22 FA 0.78 Pb(I 0.85 Br 0.15 )3 is prepared directly on the surface of the CNT interface modification layer, and the subsequent steps are the same as in Example 1.

[0095] The stacked cells obtained in Examples 1-5 and Comparative Examples 1-4 are subjected to performance testing, and the specific testing method is as follows: using a solar simulator and an I-V tester, under 1 standard solar intensity, the electrical performance of the cells obtained in the above examples and comparative examples is tested by steady-state power output test, and the test results are shown in Table 1.

[0096] Table 1

[0097] As can be seen from the data in Table 1, compared with Comparative Example 1, in Examples 1-5, by setting a first interface modification layer between the hole transport layers, the oxygen-containing functional groups (such as carboxyl groups and epoxy groups) on the modified GO surface can interact with NiO. x Or defect sites in the perovskite active layer (such as uncoordinated Pb) 2+ GO can form coordination bonds or hydrogen bonds (such as dangling bonds) to suppress nonradiative recombination, thereby increasing the open-circuit voltage (Voc) of perovskite solar cells. The oxygen-containing functional groups (such as carboxyl groups) of modified GO are hydrophilic, which can improve the interface wettability problem and improve the quality of subsequent film formation. CNTs can construct high-mobility channels, and modified GO can fill the gaps in the CNT network, thereby increasing the fill factor (FF) of perovskite solar cells.

[0098] Compared to Example 2, the setting of the second interface modification layer in Example 1 can further enhance the passivation effect on the hole transport layer, better improve interface defects, and thus improve battery efficiency.

[0099] In Comparative Example 2, only a GO modification layer was set, which has poor conductivity and is easy to stack, making it difficult to form a stable, uniform and conductive interface layer. Therefore, the effect on improving the battery efficiency of the stacked battery is poor.

[0100] In Comparative Example 3, only a CNT modification layer was set. Although its conductivity was good, its ability to repair defects in the hole transport layer was poor, and the interface passivation effect was not good. Consequently, the effect on improving the battery efficiency of the stacked battery was poor.

[0101] In Comparative Example 4, GO-NH2 and CNT were set up as two independent layers, forming a NiO / GO-NH2 / CNT / perovskite active layer structure. This introduces new interfaces, each of which is a potential charge trap, leading to increased recombination, especially at the GO-NH2-CNT interface and the CNT-perovskite active layer interface. The GO-NH2 and CNT bonds are only physically adsorbed, and their binding force is much weaker than that of composite structures connected by covalent bonds or molecular bridges. The GO-NH2 and CNT bonds are only physically contacted by van der Waals forces, resulting in high contact resistance at the GO-NH2-CNT interface and increasing recombination. The hydrophobic nature of CNTs exacerbates the perovskite film formation problem, leading to severe recombination at the CNT-perovskite active layer interface.

[0102] The terms "first" and "second" used in this document are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature marked "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0103] In the description of the specification, the description using the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the particular feature, structure, material or characteristic being described is included in at least one embodiment or example of the present application. The illustrative appearance of the above terms in various places in the specification is not intended to be taken to mean that in all contexts the terms convey the same meaning. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. Furthermore, in non-contradictory cases, those skilled in the art can combine and combine the features of different embodiments or examples described in the specification.

[0104] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary, and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A perovskite cell, characterized in that, Comprising: a first transparent conductive layer, a first charge transport layer, a perovskite active layer, a second charge transport layer and a second transparent conductive layer, one of the first charge transport layer and the second charge transport layer is a hole transport layer, and the other is an electron transport layer; Further comprising: a first interface modification layer, the first interface modification layer is arranged between the hole transport layer and the perovskite active layer, and the first interface modification layer comprises graphene oxide and carbon nanotubes, wherein, The graphene oxide surface is connected with a functional group or a lead ion, and the functional group comprises at least one of an amino group, a thiol group and a quaternary ammonium salt group.

2. The perovskite cell according to claim 1, characterized in that, The first interface modification layer further comprises reduced graphene oxide, and / or the thickness of the first interface modification layer is 5-10 nm.

3. The perovskite cell according to claim 1 or 2, characterized in that, Further comprising a second interface modification layer, the second interface modification layer is arranged between the first interface modification layer and the hole transport layer, and the second interface modification layer comprises graphene oxide or comprises graphene oxide and reduced graphene oxide.

4. The perovskite cell according to claim 3, characterized in that, The thickness of the second interface modification layer is 1-4 nm, and / or the surface of the graphene oxide in the second interface modification layer is connected with the functional group or the lead ion.

5. A method of preparing the perovskite cell according to any one of claims 1 to 4, characterized in that, Comprising the steps of preparing a first transparent conductive layer, a first charge transport layer, a perovskite active layer, a second charge transport layer and a second transparent conductive layer, one of the first charge transport layer and the second charge transport layer is a hole transport layer, and the other is an electron transport layer, further comprising: forming a first interface modification layer between the hole transport layer and the perovskite active layer, and the method for forming the first interface modification layer comprises: coating a first interface modification liquid containing graphene oxide and carbon nanotubes, and heat treating to obtain the first interface modification layer, wherein the surface of the graphene oxide is connected with a functional group or a lead ion, and the functional group comprises at least one of an amino group, a thiol group and a quaternary ammonium salt group.

6. The method of claim 5, wherein, In the first interface modification liquid, the concentration of graphene oxide is 0.05-0.25 mg / mL, and the concentration of carbon nanotubes is 0.05-0.15 mg / mL, And / or, the temperature of the heat treatment is 100-150°C, and the time is 10-30 minutes.

7. The method according to claim 5 or 6, characterized in that, Further comprising: forming a second interface modification layer between the first interface modification layer and the hole transport layer, and the method for forming the second interface modification layer comprises: coating a second interface modification liquid, and annealing to obtain the second interface modification layer.

8. The method of claim 7, wherein, The concentration of graphene oxide in the second interface modification liquid is 0.1-0.5 mg / mL.

9. A stacked battery characterized by comprising: Comprising: a crystalline silicon bottom cell and a perovskite top cell located on the light-receiving surface of the crystalline silicon bottom cell, and the perovskite top cell is the perovskite cell according to any one of claims 1-8.

10. A photovoltaic module, characterized by, Comprising the perovskite cell according to any one of claims 1-4, or comprising the stacked cell according to claim 9.

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