Thin-film solar cell, photovoltaic module and power generation equipment

Abstract

The invention provides a thin-film solar cell, a photovoltaic module and power generation equipment, and relates to the field of photovoltaic technology. The thin-film solar cell comprises a first electrode, a hole transport layer, a light absorption layer, an electron transport layer, an oxide layer and a second electrode which are stacked in sequence. And an interface layer is arranged between the electron transport layer and the oxide layer. The material of the electron transport layer comprises fullerene. The material of the interface layer comprises fullerene modified with groups. And the fullerene modified with the groups is chemically bonded with the oxide layer. In the fullerene modified with the group, the fullerene is directly connected with the group. Thus, the bonding strength of the electron transport layer and the oxide layer can be improved through the interface layer, it is guaranteed that photoelectron current generated by light absorption of the light absorption layer can quickly flow to the second electrode through the electron transport layer, the interface layer and the oxide layer, and the output power of the thin-film solar cell can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic technology, and particularly relates to a thin-film solar cell, a photovoltaic module and a power generation device. BACKGROUND

[0002] In the existing thin-film solar cell, a top electrode is formed on the side of an electron transport layer away from a light-absorbing layer by sputtering. In order to avoid damage to the electron transport layer and the light-absorbing layer in the sputtering process, an oxide layer is arranged between the electron transport layer and the top electrode. However, the oxide layer of the existing thin-film solar cell is prone to being separated from the electron transport layer, resulting in the problems of poor reliability and stability of the thin-film solar cell. SUMMARY

[0003] The present application provides a thin-film solar cell, a photovoltaic module and a power generation device, and aims to solve the technical problem of poor reliability and stability of the thin-film solar cell.

[0004] In a first aspect, an embodiment of the present application provides a thin-film solar cell. The thin-film solar cell comprises a first electrode, a hole transport layer, a light-absorbing layer, an electron transport layer, an oxide layer and a second electrode which are sequentially stacked along the thickness direction of the thin-film solar cell; wherein an interface layer is arranged between the electron transport layer and the oxide layer, the material of the electron transport layer comprises fullerene, the material of the interface layer comprises fullerene modified with a group, the fullerene modified with the group is chemically bonded with the oxide layer, and in the fullerene modified with the group, the fullerene is directly connected with the group.

[0005] In the thin-film solar cell provided by the embodiment of the present application, the light-absorbing layer is used for photoelectric conversion. The light-absorbing layer can absorb light and generate a photoelectron flow and a photohole flow. The photohole flow flows to the first electrode through the hole transport layer, and the photoelectron flow flows to the second electrode through the electron transport layer, the interface layer and the oxide layer. The thin-film solar cell can output a photoelectric current. The oxide layer is combined with the electron transport layer through the interface layer. The oxide layer can protect the light-absorbing layer and the electron transport layer, and can avoid damage to the light-absorbing layer and the electron transport layer in the process of forming the second electrode, thereby improving the structural stability and reliability of the thin-film solar cell.

[0006] The material of the electron transport layer includes a fullerene, and the material of the interface layer includes a fullerene modified with a group. The design that the fullerene modified with a group is chemically bonded with the oxide layer has the following advantages. On the one hand, the electron transport layer and the interface layer can be conjugated and have a large binding force because the fullerene modified with a group can form a π-π bond with the fullerene. On the other hand, the interface layer and the oxide layer can be chemically bonded, and the interface layer and the oxide layer have a large binding force, which is beneficial to improve the binding strength of the oxide layer and the electron transport layer, reduce the risk of separation of the oxide layer and the electron transport layer, improve the structural stability and reliability of the thin-film solar cell, and ensure that the thin-film solar cell has a high photoelectric conversion efficiency after a long time of work. In addition, the chemical bonding of the fullerene modified with a group and the oxide layer is the chemical bonding of the group and the oxide layer. In the fullerene modified with a group, the fullerene is directly connected with the group, which has the following advantages. On the one hand, other groups between the group and the fullerene can be avoided, which is beneficial to shorten the length of the molecular chain of the fullerene modified with a group, improve the efficiency of the flow of photoelectrons from the electron transport layer to the second electrode through the interface layer, and improve the output power of the thin-film solar cell. On the other hand, the concentration of the group in the fullerene modified with a group can be improved, the binding strength between the interface layer and the oxide layer can be improved, the structural stability and reliability of the thin-film solar cell can be improved, and the photoelectric conversion efficiency of the thin-film solar cell after a long time of work can be improved.

[0007] In a possible implementation, the group includes at least one of a hydroxyl group, an amino group, a carboxyl group, and a sulfur group.

[0008] In this way, the group can form a covalent bond with the oxide layer, and the interface layer and the oxide layer have a large binding force. The group has various types, and the interface layer can be made of a suitable fullerene modified with a group according to actual needs. In addition, when the group includes a hydroxyl group, the hydroxyl group of one of the two fullerenols modified with a group can form an oxygen bond with the hydroxyl group of the other. The design that the group includes a hydroxyl group has the following advantages. On the one hand, the strength of the interface layer can be improved, and the reliability and stability of the interface layer can be improved. On the other hand, the movement of ions in the light-absorbing layer can be inhibited, and the stability of photoelectric conversion of the light-absorbing layer can be improved.

[0009] In a possible implementation, the fullerene modified with a group is a fullerenol.

[0010] The fullerols are fullerenes only modified with hydroxyl groups. In two fullerol molecules, the hydroxyl group of one of the fullerols forms an oxygen bond with the hydroxyl group of the other fullerol. The design of the interface layer made of the fullerols not only helps to improve the strength of the interface layer, but also helps to improve the reliability and stability of the interface layer; and can inhibit the movement of ions in the light-absorbing layer, and helps to improve the stability and conversion efficiency of the photoelectric conversion of the light-absorbing layer. In addition, since the preparation of the fullerols is relatively mature and the processing difficulty is low, this helps to reduce the processing cost of the interface layer.

[0011] In a possible implementation, the fullerenes in the fullerenes modified with the groups are the same as the fullerenes in the material of the electron transport layer.

[0012] In this way, the conjugative binding force between the electron transport layer and the interface layer is ensured to be large, which helps to improve the structural stability and reliability of the thin-film solar cell.

[0013] In a possible implementation, the size of the interface layer in the thickness direction of the thin-film solar cell is smaller than the size of the electron transport layer in the thickness direction of the thin-film solar cell, and smaller than the size of the oxide layer in the thickness direction of the thin-film solar cell.

[0014] In this way, the size of the interface layer in the thickness direction of the thin-film solar cell is ensured to be small, which helps to improve the efficiency of the flow of the photoelectron current to the second electrode, and helps to improve the output power of the thin-film solar cell.

[0015] In a possible implementation, the conduction band energy level of the electron transport layer is smaller than the conduction band energy level of the light-absorbing layer and larger than the conduction band energy level of the interface layer.

[0016] In this way, the photoelectron current can quickly and stably flow to the second electrode through the electron transport layer, the interface layer and the oxide layer, which helps to improve the output power of the thin-film solar cell.

[0017] In a possible implementation, the difference between the conduction band energy level of the electron transport layer and the conduction band energy level of the interface layer is less than 0.4 eV.

[0018] In this way, the electron transport layer and the interface layer can be matched in energy level, which on one hand can avoid the energy level difference between the electron transport layer and the interface layer being too large to form an energy barrier, so that the photoelectron current is difficult to flow out of the electron transport layer, and the damage of the light-absorbing layer and the electron transport layer caused by the accumulation of the photoelectron current in the light-absorbing layer and the electron transport layer is avoided, which helps to prolong the service life of the thin-film solar cell and improve the working stability of the thin-film solar cell; on the other hand, the energy level difference between the electron transport layer and the interface layer being too small to cause the driving force of the photoelectron current to be too small is avoided, which helps to improve the efficiency of the photoelectron current flowing from the electron transport layer to the second electrode through the interface layer, and helps to improve the output power of the thin-film solar cell.

[0019] In a possible implementation, at least one of the surface of the interface layer facing the electron transport layer and the surface of the interface layer facing the oxide layer is a rough surface.

[0020] The surface of the interface layer facing the electron transport layer being a rough surface is beneficial to increase the contact area of the interface layer and the electron transport layer, and beneficial to improve the connection strength of the interface layer and the electron transport layer. The surface of the interface layer facing the oxide layer being a rough surface is beneficial to increase the contact area of the interface layer and the oxide layer, and beneficial to improve the connection strength of the interface layer and the oxide layer.

[0021] In a possible implementation, at least one of the surface of the interface layer facing the electron transport layer and the surface of the interface layer facing the oxide layer is provided with a groove.

[0022] The surface of the interface layer facing the electron transport layer being provided with a groove is beneficial to not only increase the contact area of the interface layer and the electron transport layer, and improve the connection strength of the interface layer and the electron transport layer, but also form the same interface layer in different thin-film solar cells, and improve the processing consistency of the thin-film solar cells. The surface of the interface layer facing the oxide layer being provided with a groove is beneficial to not only increase the contact area of the interface layer and the oxide layer, and improve the connection strength of the interface layer and the oxide layer, but also form the same interface layer in different thin-film solar cells, and improve the processing consistency of the thin-film solar cells.

[0023] In a possible implementation, the groove includes an opening and a bottom wall oppositely arranged in the thickness direction of the thin-film solar cell, and in the direction in which the opening points to the bottom wall, the size of the groove in a first direction gradually decreases, and the first direction is perpendicular to the thickness direction of the thin-film solar cell.

[0024] In this way, the groove arranged on the surface of the interface layer facing the electron transport layer can reduce the stress concentration between the interface layer and the electron transport layer, and is beneficial to improve the connection strength and reliability of the interface layer and the electron transport layer. The groove arranged on the surface of the interface layer facing the oxide layer can reduce the stress concentration between the interface layer and the oxide layer, and is beneficial to improve the connection strength and reliability of the interface layer and the oxide layer.

[0025] In a second aspect, the embodiments of the present application further provide a photovoltaic module. The photovoltaic module includes a plurality of thin-film solar cells according to any one of the first aspect, and the plurality of thin-film solar cells are connected in series.

[0026] In a third aspect, the embodiments of the present application further provide a power generation device. The power generation device includes a shell and the photovoltaic module according to the second aspect, and the photovoltaic module is arranged in the shell. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0028] Figure 1 This is a structural block diagram of a power generation device provided in an embodiment of the present application;

[0029] Figure 2 is a schematic diagram of the three-dimensional structure of a thin-film solar cell provided in an embodiment of the present application;

[0030] Figure 3 yes Figure 2 The thin film solar cell shown is a schematic structural diagram cut along line AA;

[0031] Figure 4 This is a comparison chart of the results of the electron transport layer directly bonding with the oxide layer and the electron transport layer bonding with the oxide layer through the interface layer under the tape test;

[0032] Figure 5 yes Figure 3 Result diagram of the thin film solar cell shown and the thin film solar cell shown in the comparative example under maximum power point test;

[0033] Figure 6 yes Figure 3 Result diagram of the thin film solar cell shown and the thin film solar cell shown in the comparative example under damp heat test;

[0034] Figure 7 yes Figure 3 Result diagram of the thin film solar cell shown and the thin film solar cell shown in the comparative example under hot and cold cycle test;

[0035] Figure 8 yes Figure 3 Result diagram of the thin-film solar cell shown in FIG. 1 and the thin-film solar cell shown in the comparative example under the humidity-freeze cycle test;

[0036] Figure 9 is a schematic structural diagram of another thin-film solar cell provided in an embodiment of the present application;

[0037] Figure 10 is a schematic structural diagram of another thin-film solar cell provided in an embodiment of the present application;

[0038] Figure 11 is a schematic structural diagram of another thin-film solar cell provided in an embodiment of the present application;

[0039] Figure 12 yes Figure 11 An enlarged view of part XII of the thin film solar cell is shown. DETAILED DESCRIPTION

[0040] Embodiments of the present application provide a thin-film solar cell, a photovoltaic module and a power generation device. The thin-film solar cell is applied to the photovoltaic module, and the photovoltaic module is applied to the power generation device. The power generation device is an electronic device capable of converting light energy into electric energy.

[0041] The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0042] Please refer to Figure 1 , Figure 1 is a structural block diagram of a power generation device 1000 provided by embodiments of the present application.

[0043] As shown in Figure 1 , the power generation device 1000 can be used to supply power to a load 3000. For example, the power generation device 1000 can supply power to the load 3000 through a power conversion device 2000. Specifically, the power generation device 1000 includes a photovoltaic module 1 and a housing 2. The photovoltaic module 1 is mounted on the housing 2. The housing 2 is used to protect the photovoltaic module 1. The photovoltaic module 1 is used to convert light energy into electric energy and output direct current. The photovoltaic module 1 includes a plurality of thin-film solar cells 100, and the plurality of thin-film solar cells 100 are connected in series. Each thin-film solar cell 100 can convert light energy into electric energy, and each thin-film solar cell 100 is used for photoelectric conversion. The power conversion device 2000 can be used to convert the direct current output by the photovoltaic module 1 into alternating current to supply the load 3000. The load 3000 can be an electronic device using alternating current, such as a motor, a fan or an air conditioner. The power conversion device 2000 can be a photovoltaic inverter or other inverter. The power conversion device 2000 can also be used to convert the direct current output by the photovoltaic module 1 into alternating current to supply a power grid. The power conversion device 2000 can also be used to perform voltage conversion processing on the direct current output by the photovoltaic module 1. The direct current after the voltage conversion processing by the power conversion device 2000 can be transmitted to the load 3000 to supply the load 3000. The load 3000 can be an electronic device using direct current, such as a battery. In some other embodiments, the number of photovoltaic modules 1 can also be multiple, and the multiple photovoltaic modules 1 are connected in series.

[0044] In the existing thin-film solar cell, the second electrode is formed on the side of the electron transport layer away from the light-absorbing layer by sputtering. In order to avoid damage to the electron transport layer and the light-absorbing layer during sputtering, an oxide layer is arranged between the electron transport layer and the second electrode. However, the oxide layer of the existing thin-film solar cell is easy to separate from the electron transport layer, resulting in the problems of poor reliability and stability of the thin-film solar cell.

[0045] To solve the above problems, the embodiment of the present application provides a thin-film solar cell, a photovoltaic module and a power generation device. An interface layer is arranged between the oxide layer and the electron transport layer to improve the bonding force between the oxide layer and the electron transport layer, so as to avoid the separation of the oxide layer and the electron transport layer, and improve the reliability and stability of the thin-film solar cell.

[0046] Please refer to Figure 2 and Figure 3 , Figure 2 is a schematic diagram of a three-dimensional structure of a thin-film solar cell 100 provided by the embodiment of the present application. Figure 3 is Figure 2 a schematic diagram of a structure of the thin-film solar cell 100 along the A-A line. For the convenience of description, the direction perpendicular to the thickness direction (the direction of the Z axis shown in the figure) of the thin-film solar cell 100 is defined as the first direction (i.e. the direction of the X axis shown in the figure), and the direction perpendicular to both the first direction and the thickness direction of the thin-film solar cell 100 is defined as the second direction (i.e. the direction of the Y axis shown in the figure). In the embodiment, the first direction (i.e. the direction of the X axis shown in the figure) is the width direction of the thin-film solar cell 100, and the second direction (i.e. the direction of the Y axis shown in the figure) is the length direction of the thin-film solar cell 100. In some other embodiments, the first direction (i.e. the direction of the X axis shown in the figure) can also be the length direction of the thin-film solar cell 100, and the second direction (i.e. the direction of the Y axis shown in the figure) can also be the width direction of the thin-film solar cell 100.

[0047] As shown in Figure 2 and Figure 3 , the thin-film solar cell 100 includes a first electrode 10, a hole transport layer 20, a light absorption layer 30, an electron transport layer 40, an oxide layer 50 and a second electrode 60 which are sequentially stacked along the Z axis direction (i.e. the thickness direction of the thin-film solar cell 100). An interface layer 70 is arranged between the electron transport layer 40 and the oxide layer 50. The electron transport layer 40 and the oxide layer 50 are combined through the interface layer 70. The thin-film solar cell 100 further includes a substrate 101 which is stacked on the side of the first electrode 10 away from the light absorption layer 30. The substrate 101 is used to support the first electrode 10, the hole transport layer 20, the light absorption layer 30, the electron transport layer 40, the oxide layer 50, the second electrode 60 and the interface layer 70. The substrate 101 can be a transparent conductive material including but not limited to patterned conductive glass.

[0048] The light-absorbing layer 30 is used for photoelectric conversion. The light-absorbing layer 30 absorbs light and generates a flow of photoholes and photoelectrons. The photoholes flow through the hole transport layer 20 to the first electrode 10, and the photoelectrons flow through the electron transport layer 40 and the oxide layer 50 to the second electrode 60. The thin-film solar cell 100 outputs direct current through the first electrode 10 and the second electrode 60. In two thin-film solar cells 100 connected in series, the first electrode 10 of one thin-film solar cell 100 is electrically connected to the second electrode 60 of the other thin-film solar cell 100. Specifically, the first electrode 10 of one thin-film solar cell 100 is electrically connected to the second electrode 60 of the other thin-film solar cell 100 through the substrate 101.

[0049] Exemplarily, both the first electrode 10 and the second electrode 60 are transparent electrodes. The material of the first electrode 10 and the material of the second electrode 60 both include a transparent conductive oxide (TCO). The TCO can be made of one or more materials including, but not limited to, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and indium zinc oxide (IZO). In this way, light can be incident from the first electrode 10 and the second electrode 60 into the light absorbing layer 30, which can absorb light and perform photoelectric conversion, thereby improving the photoelectric conversion efficiency of the light absorbing layer 30. It should be noted that the material of feature A including material B means that feature A is made of at least material B.

[0050] In some other embodiments, the first electrode 10 (or the second electrode 60) may be a metal electrode. Exemplarily, the material of the first electrode 10 (or the material of the second electrode 60) may include a metal material, which may include but is not limited to one or more of Al (aluminum), Ag (silver), Au (gold), Mo (molybdenum), Cr (chromium), Ti (titanium), Ni (nickel), Cu (copper), or Pt (platinum).

[0051] The material of the hole transport layer 20 includes a P-type semiconductor, which can be made of one or more materials including, but not limited to, nickel oxide (NiO), cuprous oxide (Cu2O), molybdenum trioxide (MoO3), cuprous iodide (Cul), cuprous thiocyanate (CuSCN), reduced graphene oxide, poly[ bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly[bis(4-phenyl)(4-butylphenyl)amine] (Ploy-TPD), and poly(4-(3,6-dimethyl-9H-carbazol-9-yl)butyl) phosphonic acid) (Poly-4PACz:PSS) or poly(4-(3,6-dimethyl-9H-carbazol-9-yl)butyl) phosphonic acid) (Poly-4PACz).

[0052] The material of the light absorption layer 30 includes a perovskite, which can be one or more materials including, but not limited to, ABX3-type perovskite; wherein A+is one or more of Rb+, Cs+, CH3NH3+(MA+), H2C(=NH)NH2(FA), B is one or more of Pb, Sn, and other metal elements, and X is one or more of I, Br, Cl, F, and other halogen elements.

[0053] The material of the electron transport layer 40 includes a fullerene. Exemplarily, the fullerene is C 60 In other embodiments, the fullerene in the material of the electron transport layer 40 can also be one or more of C 70 , C 20 , C 76 , or C 80 The electron transport layer 40 made of the fullerene facilitates the flow of photoelectrons. In this way, the efficiency of the flow of photoelectrons from the electron transport layer 40 to the second electrode 60 is improved, and the photoelectric conversion efficiency of the thin-film solar cell 100 is improved.

[0054] The material of the interface layer 70 includes a fullerene modified with a group, and the fullerene modified with a group is chemically bonded to the oxide layer 50. In the fullerene modified with a group, the fullerene is directly connected to the group. Specifically, the fullerene is connected to the group by a covalent bond. For ease of description, the fullerene in the material of the electron transport layer 40 is defined as a first fullerene, and the fullerene in the fullerene modified with a group is defined as a second fullerene, that is, the fullerene modified with a group includes the second fullerene and the group, and the second fullerene is directly connected to the group. Specifically, the second fullerene is connected to the group by a covalent bond.

[0055] The group is chemically bonded to the oxide layer 50. Specifically, the group can form a chemical bond with the oxide. The interface layer 70 is combined with the oxide layer 50 by a chemical bond. The fullerene can be conjugated with the fullerene modified with a group, the first fullerene can form a π-π bond with the second fullerene (that is, the fullerene in the fullerene modified with a group), and the interface layer 70 is conjugated with the electron transport layer 40. The existence of the π-π bond can be confirmed by methods including but not limited to ultraviolet-visible spectroscopy. For example, the number of groups can be multiple, and the number of groups can be 2, 3, or more.

[0056] The thin-film solar cell 100 provided by the embodiments of the present application includes an optical absorption layer 30 for photoelectric conversion. The optical absorption layer 30 can absorb light and generate a stream of photoelectrons and a stream of photo holes. The stream of photo holes flows to the first electrode 10 through the hole transport layer 20, and the stream of photoelectrons flows to the second electrode 60 through the electron transport layer 40, the interface layer 70, and the oxide layer 50. The thin-film solar cell 100 can output a photoelectric current. The oxide layer 50 is combined with the electron transport layer 40 through the interface layer 70. The oxide layer 50 can protect the optical absorption layer 30 and the electron transport layer 40, and can avoid damage to the optical absorption layer 30 and the electron transport layer 40 during the formation of the second electrode 60. The structural stability and reliability of the thin-film solar cell 100 are improved.

[0057] The material of the electron transport layer 40 includes a fullerene, and the material of the interface layer 70 includes a fullerene modified with a group, which is chemically bonded to the oxide layer 50. On the one hand, the fullerene modified with a group can form a π-π bond with the fullerene, and the electron transport layer 40 and the interface layer 70 can be conjugated and have a large binding force. On the other hand, the interface layer 70 and the oxide layer 50 can be combined by a chemical bond, and the interface layer 70 and the oxide layer 50 have a large binding force. This is conducive to improving the binding strength of the oxide layer 50 and the electron transport layer 40, reducing the risk of separation of the oxide layer 50 and the electron transport layer 40, improving the structural stability and reliability of the thin-film solar cell 100, and ensuring that the thin-film solar cell 100 has a high photoelectric conversion efficiency after a long time of work.

[0058] In addition, since the chemical bonding of the group-modified fullerene and the oxide layer 50 is specifically the chemical bonding of the group and the oxide layer 50; in the group-modified fullerene, the design that the fullerene is directly connected with the group, on one hand, can avoid the existence of other groups between the group and the fullerene, is conducive to shortening the length of the molecular chain of the group-modified fullerene, is conducive to improving the efficiency of the photoelectron flow from the electron transport layer 40 to the second electrode 60 through the interface layer 70, is conducive to improving the output power of the thin-film solar cell 100; on the other hand, is conducive to improving the concentration of the group in the group-modified fullerene, is conducive to improving the bonding strength between the interface layer 70 and the oxide layer 50, is conducive to improving the structural stability and reliability of the thin-film solar cell 100, and is conducive to improving the photoelectric conversion efficiency of the thin-film solar cell 100 after a long time of work.

[0059] In some embodiments, the second fullerene (i.e., the fullerene in the group-modified fullerene) is the same as the first fullerene (i.e., the fullerene in the material of the electron transport layer 40). Specifically, the number of carbon atoms in the second fullerene is the same as the number of carbon atoms in the first fullerene. For example, the number of carbon atoms in the second fullerene and the number of carbon atoms in the first fullerene are both 60, that is, the second fullerene and the first fullerene are both C 60 . In this way, the conjugate bonding force between the electron transport layer 40 and the interface layer 70 is guaranteed to be large, which is conducive to improving the structural stability and reliability of the thin-film solar cell 100. In other embodiments, the second fullerene and the first fullerene can also be C 70 , C 20 or C 80 , etc. In other embodiments, the second fullerene and the first fullerene can also be different.

[0060] In some embodiments, the group can include at least one of a hydroxyl group (-OH), an amino group (-NH2), a carboxyl group (-COOH), and a sulfur group (-SH). Among them, the hydroxyl group, the amino group, the carboxyl group, and the sulfur group can all be directly connected with the second fullerene. Specifically, the hydroxyl group can be directly connected with the second fullerene and form a carbon-oxygen (C-O) covalent bond, the amino group can be directly connected with the second fullerene and form a carbon-nitrogen (C-N) covalent bond, the carboxyl group can be directly connected with the second fullerene and form a carbon-oxygen (C-O) covalent bond or a carbon-carbon (C-C) covalent bond, and the sulfur group can be directly connected with the second fullerene and form a carbon-sulfur (C-S) covalent bond. The group-modified fullerene can be covalently bonded with the oxide layer 50. Specifically, the group can be covalently bonded with the oxide layer 50.

[0061] The hydroxyl group, the amino group, the carboxyl group and the sulfide group can form a chemical bond with the oxide layer 50. The chemical bond is exemplarily a covalent bond. Specifically, the hydroxyl group can form a tin-oxygen (Sn-O) covalent bond with the tin oxide, the amino group can form a nitrogen-tin (N-Sn) covalent bond with the tin oxide, the carboxyl group can form a carbon-oxygen-tin (C-O-Sn) covalent bond with the tin oxide, and the sulfide group can form a sulfur-tin (S-Sn) covalent bond with the tin oxide. The existence of the covalent bond can be confirmed by methods including but not limited to infrared spectroscopy, X-ray diffraction or energy spectrum and surface analysis.

[0062] In this way, the group can form a covalent bond with the oxide layer 50, so as to ensure that the interface layer 70 has a large bonding force with the oxide layer 50. The group can be various, and the interface layer 70 can be made of the fullerene modified with the group according to actual needs. In addition, when the group includes the hydroxyl group, the hydroxyl group of one of the two molecules of the fullerene modified with the group can form an oxygen bond with the hydroxyl group of the other. The design of the group including the hydroxyl group is beneficial to improving the strength of the interface layer 70, and is beneficial to improving the reliability and stability of the interface layer 70. On the other hand, the design of the group including the hydroxyl group can inhibit the movement of ions in the light-absorbing layer 30, and is beneficial to improving the stability of the photoelectric conversion of the light-absorbing layer 30. In other embodiments, the group can also form an ionic bond with the oxide layer 50.

[0063] In Figure 2 and Figure 3 the embodiments shown, the fullerene modified with the group is a fullerol. That is, the group only includes the hydroxyl group, and the number of the hydroxyl group can be one or more. The molecular formula of the fullerol (i.e., the fullerene modified with the group) can be:

[0064]

[0065] wherein the second fullerene is C 60 n represents the number of the hydroxyl group (i.e., the group), and n≥1.

[0066] The fullerol is the fullerene modified only with the hydroxyl group. The hydroxyl group of one of the two molecules of the fullerol can form an oxygen bond with the hydroxyl group of the other. The design of the interface layer 70 made of the fullerol is not only beneficial to improving the strength of the interface layer 70, and is beneficial to improving the reliability and stability of the interface layer 70, but also can inhibit the movement of ions in the light-absorbing layer 30, and is beneficial to improving the stability and conversion efficiency of the photoelectric conversion of the light-absorbing layer 30. In addition, since the preparation of the fullerol is relatively mature and the processing difficulty is low, this is beneficial to reducing the processing cost of the interface layer 70.

[0067] In other embodiments, the second fullerene is also C 70 , C 20 or C 80 , etc. For example, the molecular formula of the fullerol (i.e., the fullerene modified with the group) can also be:

[0068]

[0069] Among them, the second fullerene is C 70 , n represents the number of hydroxyl groups (ie groups), n≥1.

[0070] In other embodiments, the fullerene modified with groups may include multiple groups, including at least one hydroxyl group, at least one amino group, at least one carboxyl group, and at least one thiol group. Each hydroxyl group, each amino group, each carboxyl group, and each thiol group is directly connected to the second fullerene. It is understood that any one, any two, or any three of the hydroxyl, amino, carboxyl, and thiol groups may be omitted to form different embodiments.

[0071] In some embodiments, the conduction band energy level of the electron transport layer 40 is lower than the conduction band energy level of the light absorbing layer 30 and higher than the conduction band energy level of the interface layer 70. This ensures that the photoelectron flux can flow quickly and stably through the electron transport layer 40, the interface layer 70, and the oxide layer 50 to the second electrode 60, which is beneficial for improving the output power of the thin-film solar cell 100.

[0072] Furthermore, the difference between the conduction band energy level of the electron transport layer 40 and the conduction band energy level of the interface layer 70 is less than 0.4 eV. Figure 2 and Figure 3 In the embodiment shown, the conduction band energy level of the light absorbing layer 30 made of perovskite is -3.9 eV, the conduction band energy level of the electron transport layer 40 made of fullerene is -4.3 eV, and the conduction band energy level of the interface layer 70 made of fullerol is -4.31 eV. In this way, the electron transport layer 40 can achieve energy level matching with the interface layer 70. On the one hand, it can avoid the energy level gap between the electron transport layer 40 and the interface layer 70 being too large to form an energy barrier, which makes it difficult for the photoelectron flow to flow out of the electron transport layer 40, and avoids the photoelectron flow accumulating in the light absorbing layer 30 and the electron transport layer 40, causing damage to the light absorbing layer 30 and the electron transport layer 40, which is beneficial to extending the working life of the thin-film solar cell 100 and improving the working stability of the thin-film solar cell 100; on the other hand, it can avoid the energy level gap between the electron transport layer 40 and the interface layer 70 being too small, which leads to too small a driving force for the photoelectron flow, which is beneficial to improving the efficiency of the photoelectron flow from the electron transport layer 40 through the interface layer 70 to the second electrode 60, and is beneficial to improving the output power of the thin-film solar cell 100.

[0073] In some embodiments, the interface layer 70 has a dimension in the Z-axis direction (i.e., the thickness direction of the thin-film solar cell 100) that is smaller than a dimension of the electron transport layer 40 in the Z-axis direction (i.e., the thickness direction of the thin-film solar cell 100) and smaller than a dimension of the oxide layer 50 in the Z-axis direction (i.e., the thickness direction of the thin-film solar cell 100). In this way, the interface layer 70 has a dimension in the Z-axis direction (i.e., the thickness direction of the thin-film solar cell 100) that is small, which is conducive to improving the efficiency of the flow of photoelectrons to the second electrode 60 and improving the output power of the thin-film solar cell 100.

[0074] In some embodiments, a buffer layer 80 is provided between the light-absorbing layer 30 and the electron transport layer 40, and the buffer layer 80 is stacked between the light-absorbing layer 30 and the electron transport layer 40. For example, the buffer layer 80 is a two-dimensional perovskite layer. The design of the buffer layer 80 can optimize the interface properties between the light-absorbing layer 30 and the electron transport layer 40, which is conducive to improving the efficiency of the flow of photoelectrons from the light-absorbing layer 30 to the electron transport layer 40, improving the output power of the thin-film solar cell 100, and protecting the light-absorbing layer 30, which is conducive to improving the structural stability and reliability of the thin-film solar cell 100.

[0075] In some embodiments, the thin-film solar cell 100 further includes a metal electrode 90. The metal electrode 90 is stacked on a side of the second electrode 60 that is away from the light-absorbing layer 30. For example, the metal electrode 90 can be made of one or more of Al, Ag, Au, Mo, Cr, Ti, Ni, Cu, or Pt. The second electrode 60 is electrically connected to other devices (e.g., the first electrode 10 of another thin-film solar cell 100) through the metal electrode 90. The design of the metal electrode 90 is conducive to improving the electrical conductivity of the second electrode 60 and improving the output power of the thin-film solar cell 100. In other embodiments, the second electrode 60 can be directly electrically connected to other devices.

[0076] Next, an example of a process for manufacturing the thin-film solar cell 100 shown in FIG. 1 is described. Figure 2 and Figure 3 Next, an example of a process for manufacturing the thin-film solar cell 100 shown in FIG. 1 is described.

[0077] S10, forming the first electrode 10 on the substrate 101.

[0078] Specifically, S11, the patterned conductive glass (i.e., the substrate 101) is sequentially subjected to ultrasonic treatment in deionized water, ethanol, acetone, and isopropyl alcohol. The ultrasonic treatment time can be 15 minutes. In this way, impurities on the substrate 101 can be removed, and the surface of the substrate 101 can be activated to improve the uniformity of the first electrode 10 formed on the substrate 101.

[0079] S12, dry the substrate 101 by ultraviolet-ozone treatment; wherein the treatment time can be 30 min. In this way, the organic residues on the surface of the substrate 101 can be removed, and the substrate 101 is cleaned.

[0080] S13, deposit a transparent conductive oxide on the surface of the substrate 101, and then anneal the transparent conductive oxide in an inert gas to form the first electrode 10. Exemplarily, the transparent conductive oxide can be indium tin oxide, and the inert gas can be nitrogen. The substrate 101 is placed into an atomic layer deposition system, and indium tin oxide is deposited on the surface of the substrate 101 under the condition that trimethyl indium and tetrakis(dimethylamino)tin are used as sources and the deposition temperature is 150°C. After the deposition is completed, the substrate 101 is transferred to a nitrogen glove box to be annealed and form the first electrode 10, and the first electrode 10 is arranged in a stack with the substrate 101; wherein the annealing temperature can be 150°C, and the annealing time can be 2h.

[0081] S20, form the hole transport layer 20 on the first electrode 10.

[0082] Specifically, S21, prepare a hole transport layer solution. Exemplarily, Poly-4PACz (poly(4-(3,6-dimethyl-9H-carbazol-9-yl)butyl) phosphonic acid)) is dissolved in a mixed solvent of methanol and chloroform to form a Poly-4PACz solution. In the mixed solvent of methanol and chloroform, the volume ratio of methanol to chloroform is 1:1; the solution concentration of the Poly-4PACz solution is 1 mg / mL. The Poly-4PACz solution and a PSS (poly(4-styrenesulfonic acid sodium)) aqueous solution are mixed to form a hole transport layer solution; wherein the solution concentration of the PSS aqueous solution is 4 mg / mL, and the volume ratio of the Poly-4PACz solution to the PSS aqueous solution is 8:1.

[0083] S22, spin-coat the hole transport layer solution on the first electrode 10, and then anneal to form the hole transport layer 20. Exemplarily, the hole transport layer solution is spin-coated on the first electrode 10 at a spin-coating parameter of 5000R (revolutions), 30s to form a first to-be-annealed piece, and then the first to-be-annealed piece is placed on a hot table to be annealed to form the hole transport layer 20, and the hole transport layer 20 is arranged in a stack with the first electrode 10; wherein the annealing temperature (i.e. the temperature of the hot table) can be 150°C, and the annealing time can be 10 min.

[0084] S30, form the light-absorbing layer 30 on the hole transport layer 20.

[0085] Specifically, S31, prepare a perovskite precursor solution. Exemplarily, perovskite precursor materials PbI2, FAI and CsI are mixed in a stoichiometric ratio C s0.05 FA 0.95PbI3 is dissolved in a mixed solvent of DMF (dimethylformamide) and DMSO (dimethyl sulfoxide) to form a perovskite precursor solution. In the mixed solvent of DMF and DMSO, the volume ratio of DMF to DMSO is 4:1; the solution concentration of the perovskite precursor solution is 1.4 mol / L. 20% mole fraction of MACI and 2% of PbI2 are additionally added to the perovskite precursor solution. In this way, the crystallization quality of the perovskite can be optimized, which is conducive to improving the photoelectric conversion efficiency of the thin-film solar cell 100. 0.5% of an additive is further added to the perovskite precursor solution, and the additive can be, but is not limited to, pyrene-4,5,9,10-tetraone, aspartame, theophylline, caffeine, polystyrene sulfonic acid or polystyrene sulfonate. In this way, the quality of the prepared light-absorbing layer 30 can be improved, which is conducive to improving the photoelectric conversion efficiency of the light-absorbing layer 30 and the thin-film solar cell 100.

[0086] S32, spin-coat the perovskite precursor solution on the hole transport layer 20, and then anneal to form the light-absorbing layer 30. For example, spin-coat the perovskite precursor solution on the hole transport layer 20 at a spin-coating parameter of 1000 rpm (revolutions per minute) for 10 s, and then at a spin-coating parameter of 5000 rpm for 40 s, to uniformly spin-coat the perovskite precursor solution and prepare a second to-be-annealed piece; wherein 200 μL of chlorobenzene solvent is added dropwise 10 s before the end of the spin-coating. Anneal the second to-be-annealed piece to prepare the light-absorbing layer 30, which is arranged in a stack with the hole transport layer 20; wherein the annealing temperature can be 150°C, and the annealing time can be 15 min.

[0087] S40, form a buffer layer 80 on the light-absorbing layer 30.

[0088] Specifically, S41 forms a thin film on the light-absorbing layer 30. For example, the thin film can be a lead iodide thin film. The substrate 101, the first electrode 10, the hole transport layer 20 and the light-absorbing layer 30 arranged in a stack are placed in an evaporation device, and a lead iodide thin film is formed on the light-absorbing layer 30 by means of thermal evaporation; wherein the thickness of the lead iodide thin film can be 10 nm.

[0089] S42, a modification material solution is prepared. Exemplarily, the modification material is a material including an amine salt molecule, which can include but is not limited to PEAI (phenethylammonium iodide), BAI (butylammonium iodide), OAI (octylammonium iodide), or BPAI (1-(biphenyl-2-yl)propan-2-amine hydroiodide). The amine salt molecule is dissolved in a mixed solvent of IPA (isopropyl alcohol) and DMF (dimethylformamide) to form the modification material solution. In the mixed solvent of IPA and DMF, the volume ratio of IPA to DMF is 98:2; and the concentration of the amine salt molecule in the modification material solution is 0.15 mM (mmol / L).

[0090] S43, the modification material solution is spin-coated on the thin film, and then annealed to form a buffer layer 80. Exemplarily, the modification material solution is spin-coated on the thin film at a spin-coating parameter of 5000 rpm to form a third to-be-annealed piece. The third to-be-annealed piece is annealed to form the buffer layer 80, which is stacked with the light-absorbing layer 30. The annealing temperature can be 100°C, and the annealing time can be 5 min.

[0091] S50, an electron transport layer 40 is formed on the buffer layer 80. Specifically, the substrate 101, the first electrode 10, the hole transport layer 20, the light-absorbing layer 30, and the buffer layer 80 which are sequentially stacked are placed in an evaporation device. The electron transport layer 40 is formed on the buffer layer 80 by means of thermal evaporation. Exemplarily, the electron transport layer 40 can be C 60 70. The thickness of the electron transport layer 40 can be 20 nm.

[0092] S60, an interface layer 70 and an oxide layer 50 are sequentially formed on the electron transport layer 40.

[0093] Specifically, S61, an interface layer solution is spin-coated on the electron transport layer 40, and then annealed to form the interface layer 70, so as to form a to-be-processed piece. The volume of the interface layer solution can be 100 μl (microliters). Exemplarily, the interface layer solution is a solution in which fullerol is dissolved in a methanol solution, and the fullerol can be C 60 (OH)n. Such a process is conducive to improving the bonding strength between the electron transport layer 40 and the oxide layer 50 through the interface layer 70, and is conducive to improving the structural stability and reliability of the thin-film solar cell 100. In other embodiments, the interface layer solution can also be a solution in which fullerol is dissolved in water.

[0094] S62, the workpiece is transferred to an atomic layer deposition instrument, TDMASn (tetramethyl tin amine) is used as a tin source, water is used as an oxygen source, and deposition is performed under a high temperature environment to sequentially form an interface layer 70 and an oxide layer 50 on the electron transport layer 40, and the interface layer 70 is arranged between the electron transport layer 40 and the oxide layer 50. The deposition temperature can be 100°C, and the thickness of the oxide layer 50 can be 30 nm.

[0095] S70, a second electrode 60 is formed on the oxide layer 50. The second electrode 60 is an indium tin oxide film. The sequentially arranged substrate 101, the first electrode 10, the hole transport layer 20, the light absorption layer 30, the buffer layer 80, the electron transport layer 40, the interface layer 70, and the oxide layer 50 are placed in a magnetron sputtering device, and the second electrode 60 is formed on the oxide layer 50 by sputtering of argon and oxygen. The thickness of the second electrode 60 can be 100 nm.

[0096] S80, a metal electrode 90 is formed on the second electrode 60 to form a thin-film solar cell 100. The sequentially arranged substrate 101, the first electrode 10, the hole transport layer 20, the light absorption layer 30, the buffer layer 80, the electron transport layer 40, the interface layer 70, the oxide layer 50, and the second electrode 60 are placed in an evaporation device, and the metal electrode 90 is formed on the second electrode 60 by thermal evaporation to form the thin-film solar cell 100. The metal electrode 90 can be an Au layer. The thickness of the metal electrode 90 can be 80 nm.

[0097] S90, the thin-film solar cell 100 can be packaged by PIB (butyl photovoltaic component edge sealant) and a packaging cover plate. The packaging cover plate is fixedly connected to the thin-film solar cell 100 by the PIB. The packaging temperature can be 110°C, the packaging pressure can be 900 mbar (millibar), and the packaging time can be 10 min. The packaging cover plate is made of glass, metal material, or transparent polymer, but is not limited to these. In this way, the thin-film solar cell 100 can be prevented from being polluted and interfered by external water vapor or dust, and the working life of the thin-film solar cell 100 can be prolonged.

[0098] Please refer to Figure 4 , and combine Figure 3 , Figure 4 is a comparison chart of the results of the electron transport layer 40 and the oxide layer 50 directly combined and the electron transport layer 40 combined with the oxide layer 50 through the interface layer 70 under the tape test.

[0099] As shown in Figure 3 and Figure 4 , Figure 4The results of the tape test are shown in the comparison chart of FIG. 1, which shows the results of the direct combination of the electron transport layer 40 and the oxide layer 50 and the combination of the electron transport layer 40 and the oxide layer 50 through the interface layer 70. Figure 4 (a1) is a photo of the direct deposition of the oxide layer 50 on the electron transport layer 40; the electron transport layer 40 is formed of C 60 , the oxide layer 50 is formed of SnO2. Figure 4 (a2) is a schematic diagram of the mechanical peeling of part of the oxide layer 50 in (a1) by using a tape.

[0100] Figure 4 (b1) is a photo of the deposition of the oxide layer 50 on the side of the interface layer 70 away from the electron transport layer 40; the electron transport layer 40 is formed of C 60 , the oxide layer 50 is formed of SnO2, and the interface layer 70 is formed of C 60 (OH)n solution, C 60 (OH)n solution is formed of C 60 (OH)n is dissolved in water. Figure 4 (b2) is a photo of the mechanical peeling of part of the oxide layer 50 in (b1) by using a tape.

[0101] Figure 4 (c1) is a photo of the deposition of the oxide layer 50 on the side of the interface layer 70 away from the electron transport layer 40; the electron transport layer 40 is formed of C 60 , the oxide layer 50 is formed of SnO2, and the interface layer 70 is formed of C 60 (OH)n solution, C 60 (OH)n solution is formed of C 60 (OH)n is dissolved in a methanol solution. Figure 4 (c2) is a schematic diagram of the mechanical peeling of part of the oxide layer 50 in (c1) by using a tape.

[0102] As can be seen from the above, in Figure 5 , (c1) and (c2) do not change in color, and the oxide layer 50 is not easy to peel. The interface layer 70 is formed of C 60 (OH)n solution, and C 60 (OH)n solution is C 60 (OH)n is dissolved in a methanol solution. The interface layer 70 formed by such a process is conducive to improving the strength of the combination of the electron transport layer 40 and the oxide layer 50 through the interface layer 70 and is conducive to improving the structural stability and reliability of the thin-film solar cell 100.

[0103] Please refer to Figure 6 , Figure 7 , Figure 8 andFigure 3 and in combination Figure 5 , Figure 3 is Figure 6 The result chart of the thin-film solar cell 100 shown in Figure 3 is Figure 7 The result chart of the thin-film solar cell 100 shown in Figure 3 is Figure 8 The result chart of the thin-film solar cell 100 shown in Figure 3 is Figure 3 The result chart of the thin-film solar cell 100 shown in

[0104] It should be noted that in the thin-film solar cell 100 shown in Figure 3 , the electron transport layer 40 is formed of C 60 , the oxide layer 50 is formed of SnO2, and the interface layer 70 is formed of C 60 (OH)n. The thin-film solar cell 100 shown in the comparative example is different from the thin-film solar cell 100 shown in Figure 5 in that the interface layer 70 is omitted and the electron transport layer 40 is in contact with the oxide layer 50; wherein the electron transport layer 40 is formed of C 60 and the oxide layer 50 is formed of SnO2. In Figure 6 , Figure 7 , Figure 8 and Figure 3 , X1 represents the test result of the thin-film solar cell 100 shown in Figure 3 and X2 represents the test result of the thin-film solar cell 100 shown in the comparative example.

[0105] As shown in Figure 5 and Figure 3 , the result chart of the thin-film solar cell 100 shown in Figure 5 and the thin-film solar cell 100 shown in the comparative example after working at the maximum power point for 2000h under a standard light is shown in Figure 5 . In Figure 3 , the horizontal axis represents the working time and the vertical axis represents the photoelectric conversion efficiency retention rate, the photoelectric conversion efficiency retention rate = the photoelectric conversion efficiency at the current working time / the photoelectric conversion efficiency at the beginning of working. It can be seen that Figure 3The photoelectric conversion efficiency of the thin-film solar cell 100 shown in the embodiment is 92.9% after continuous operation at the maximum power point under standard illumination for 2000 hours. The photoelectric conversion efficiency of the thin-film solar cell 100 shown in the comparative example is 86.7% after continuous operation at the maximum power point under standard illumination for 2000 hours.

[0106] like Figure 6 and Figure 3 As shown, Figure 6 The thin film solar cell 100 shown in the example and the thin film solar cell 100 shown in the comparative example were respectively operated for 1000 hours at 85°C and a relative humidity of 85%. Figure 6 The result diagram is shown in Figure 2. Figure 3 In the figure, the horizontal axis represents the working time, and the vertical axis represents the photoelectric conversion efficiency retention rate. The photoelectric conversion efficiency retention rate = the photoelectric conversion efficiency at the current working time / the photoelectric conversion efficiency at the beginning of the work. It can be seen that Figure 3 The photoelectric conversion efficiency retention rate of the thin-film solar cell 100 shown in the embodiment is 93.6% after continuous operation for 1000 hours at 85°C and a relative humidity of 85%. The photoelectric conversion efficiency retention rate of the thin-film solar cell 100 shown in the comparative example is 90.2% after continuous operation for 1000 hours at 85°C and a relative humidity of 85%.

[0107] like Figure 7 and Figure 3 As shown, Figure 6 The thin film solar cell 100 shown in the embodiment and the thin film solar cell 100 shown in the comparative example were subjected to 200 cycles of hot and cold temperatures between -40°C and 85°C. Figure 3 The result graph is shown. In each hot and cold cycle, the thin film solar cell 100 is first kept at an ambient temperature of -40℃±2℃ for 10 minutes, then the ambient temperature is gradually increased to 85℃, the thin film solar cell 100 is placed at an ambient temperature of 85℃±2℃ for 10 minutes, and then the ambient temperature is gradually reduced to -40℃. The heating rate and the cooling rate can both be 100℃ / h. The horizontal axis represents the number of hot and cold cycles, and the vertical axis represents the photoelectric conversion efficiency retention rate. The photoelectric conversion efficiency retention rate = photoelectric conversion efficiency at the current number of cycles / photoelectric conversion efficiency at the beginning of work. It can be seen that Figure 3 The photoelectric conversion efficiency of the thin-film solar cell 100 shown in the embodiment is 91.8% after 200 cycles of hot and cold temperatures at -40°C to 85°C, while the photoelectric conversion efficiency of the thin-film solar cell 100 shown in the comparative embodiment is 79.7% after 200 cycles of hot and cold temperatures at -40°C to 85°C.

[0108] like Figure 8 and Figure 3 As shown, Figure 6The thin film solar cell 100 shown in the embodiment and the thin film solar cell 100 shown in the comparative example were subjected to 10 wet-freeze cycles at -40°C to 85°C to obtain Figure 3 The result graph is shown. In each wet-freeze cycle, the thin-film solar cell 100 is first kept at an ambient temperature of -40℃±2℃ for 10 minutes, and then the ambient temperature is gradually increased to 85℃. The thin-film solar cell 100 is placed at an ambient temperature of 85℃±2℃ for 10 minutes, and then the ambient temperature is gradually reduced to -40℃. The heating rate and the cooling rate can both be 100℃ / h. In this process, the relative humidity of the environment is always increased to 85%. The horizontal axis represents the number of wet-freeze cycles, and the vertical axis represents the photoelectric conversion efficiency retention rate. The photoelectric conversion efficiency retention rate = photoelectric conversion efficiency at the current number of cycles / photoelectric conversion efficiency at the beginning of work. It can be seen that Figure 3 The photoelectric conversion efficiency retention rate of the thin-film solar cell 100 shown in the embodiment after 10 wet-freeze cycles at -40°C-85°C is 92%, and the photoelectric conversion efficiency retention rate of the thin-film solar cell 100 shown in the comparative example after 10 wet-freeze cycles at -40°C-85°C is 81.4%.

[0109] As can be seen from the above, the electron transport layer 40 and the oxide layer 50 are combined through the interface layer 70. The interface layer 70 is made of fullerol, which can improve the working stability of the thin-film solar cell 100 and is beneficial to improving the photoelectric conversion efficiency of the thin-film solar cell 100 after long-term operation.

[0110] in addition Figure 9 The thin film solar cell 100 shown has an area of ​​0.1 cm 2 The photoelectric conversion efficiency is 25.71% under the condition of 0.1 cm 2 It can be understood that the electron transport layer 40 and the oxide layer 50 are combined through the interface layer 70, and the interface layer 70 is made of fullerene, which can improve the photoelectric conversion efficiency of the thin film solar cell 100.

[0111] See also Figure 3 , and combined with Figure 9 , Figure 3 1 is a schematic structural diagram of another thin-film solar cell 100 provided in an embodiment of the present application.

[0112] like Figure 9 and Figure 9 As shown, Figure 3 The embodiment shown and Figure 9 The structures of the embodiments shown are similar, and the difference between the two is that the structure of the interface layer 70 is different. Figure 10In the illustrated embodiment, at least one of the surface of the interface layer 70 facing the electron transport layer 40 and the surface of the interface layer 70 facing the oxide layer 50 is an uneven surface. Specifically, the interface layer 70 includes a first surface 71 and a second surface 72. In the Z-axis direction, the first surface 71 and the second surface 72 are arranged opposite to each other. The first surface 71 faces the electron transport layer 40, and the second surface 72 faces the oxide layer 50. Both the first surface 71 and the second surface 72 are uneven surfaces. The first surface 71 and the second surface 72 can be irregular serrated surfaces, wavy surfaces, or other irregularly shaped surfaces.

[0113] The first surface 71 (i.e., the surface of the interface layer 70 facing the electron transport layer 40) is designed as an uneven surface, which is beneficial to increasing the contact area between the interface layer 70 and the electron transport layer 40, and is beneficial to improving the connection strength between the interface layer 70 and the electron transport layer 40, which is beneficial to improving the structural stability and reliability of the thin-film solar cell 100.

[0114] The second surface 72 (i.e., the surface of the interface layer 70 facing the oxide layer 50) is designed as an uneven surface, which is beneficial to increasing the contact area between the interface layer 70 and the oxide layer 50, and is beneficial to improving the connection strength between the interface layer 70 and the oxide layer 50, which is beneficial to improving the structural stability and reliability of the thin-film solar cell 100.

[0115] See also Figure 3 , and combined with Figure 10 , Figure 3 1 is a schematic structural diagram of another thin-film solar cell 100 provided in an embodiment of the present application.

[0116] like Figure 10 and Figure 10 As shown, Figure 3 The embodiment shown and Figure 10 The structures of the embodiments shown are similar, and the difference between the two is that the structure of the interface layer 70 is different. Figure 11In the shown embodiment, at least one of the surface of the interface layer 70 facing the electron transport layer 40 and the surface of the interface layer 70 facing the oxide layer 50 is provided with a groove 73. Specifically, the interface layer 70 includes a first surface 71 and a second surface 72. The first surface 71 is disposed opposite to the second surface 72 in the Z-axis direction. The first surface 71 faces the electron transport layer 40, and the second surface 72 faces the oxide layer 50. The first surface 71 and the second surface 72 are both provided with the groove 73. For the purpose of description, the groove 73 provided on the first surface 71 is defined as a first groove 73a, and the groove 73 provided on the second surface 72 is defined as a second groove 73b. That is, the groove 73 includes the first groove 73a and the second groove 73b, the first groove 73a is provided on the first surface 71, and the second groove 73b is provided on the second surface 72. The first groove 73a is filled with the electron transport layer 40, and the second groove 73b is filled with the oxide layer 50.

[0117] For example, the first groove 73a and the second groove 73b are both rectangular grooves. The size of the first groove 73a in the X-axis direction remains unchanged along the Z-axis direction, and the size of the second groove 73b in the X-axis direction remains unchanged along the Z-axis direction. The number of the first groove 73a and the second groove 73b can be multiple, and multiple first grooves 73a are sequentially and spaced apart along the X-axis direction, and multiple second grooves 73b are sequentially and spaced apart along the X-axis direction. In some other embodiments, the number of the first groove 73a and the second groove 73b can also be one, and the first groove 73a or the second groove 73b can be omitted.

[0118] The design that the first surface 71 (i.e., the surface of the interface layer 70 facing the electron transport layer 40) is provided with the groove 73 not only can increase the contact area of the interface layer 70 and the electron transport layer 40, but also is conducive to improving the connection strength of the interface layer 70 and the electron transport layer 40. Moreover, the groove 73 is a directional design structure, which is conducive to forming the same interface layer 70 in different thin-film solar cells 100, and is conducive to improving the processing consistency of the thin-film solar cell 100.

[0119] The design that the second surface 72 (i.e., the surface of the interface layer 70 facing the oxide layer 50) is provided with the groove 73 not only can increase the contact area of the interface layer 70 and the oxide layer 50, but also is conducive to improving the connection strength of the interface layer 70 and the oxide layer 50. Moreover, the groove 73 is a directional design structure, which is conducive to forming the same interface layer 70 in different thin-film solar cells 100, and is conducive to improving the processing consistency of the thin-film solar cell 100.

[0120] For reference, Figure 12 and Figure 10 , in combination with Figure 11 , Figure 12is another structural schematic diagram of a thin-film solar cell 100 provided by an embodiment of the present application. Figure 11 is Figure 10 is an enlarged view of the XII part of the thin-film solar cell 100 shown in

[0121] As shown in Figure 11 , Figure 12 and Figure 11 , Figure 12 and Figure 10 The embodiments shown in Figure 11 have similar structures to the embodiment shown in Figure 12 The difference between the two is that the structures of the grooves 73 are different. In the embodiments shown in ​ , the groove 73 includes an opening 731 and a bottom wall 732 arranged oppositely in the Z-axis direction (i.e., the thickness direction of the thin-film solar cell 100), and the size of the groove 73 in the X-axis direction (i.e., the first direction) gradually decreases in the direction in which the opening 731 points to the bottom wall 732. Specifically, in the first groove 73a, the size of the groove 73 in the X-axis direction (i.e., the first direction) gradually decreases in the positive direction of the Z-axis. In the second groove 73b, the size of the groove 73 in the X-axis direction (i.e., the first direction) gradually decreases in the negative direction of the Z-axis.

[0122] The first groove 73a (i.e., the groove 73 arranged on the surface of the interface layer 70 facing the electron transport layer 40) can reduce the stress concentration between the interface layer 70 and the electron transport layer 40, which is conducive to improving the connection strength and connection reliability of the interface layer 70 and the electron transport layer 40, and is conducive to improving the structural stability and reliability of the thin-film solar cell 100.

[0123] The second groove 73b (i.e., the groove 73 arranged on the surface of the interface layer 70 facing the oxide layer 50) can reduce the stress concentration between the interface layer 70 and the oxide layer 50, which is conducive to improving the connection strength and connection reliability of the interface layer 70 and the oxide layer 50, and is conducive to improving the structural stability and reliability of the thin-film solar cell 100.

Claims

1. A thin film solar cell, characterized in that: The thin-film solar cell includes a first electrode, a hole transport layer, a light absorbing layer, an electron transport layer, an oxide layer and a second electrode stacked in sequence along the thickness direction of the thin-film solar cell; wherein an interface layer is provided between the electron transport layer and the oxide layer, the material of the electron transport layer includes fullerene, the material of the interface layer includes fullerene modified with a group, the fullerene modified with a group is chemically bonded to the oxide layer, and in the fullerene modified with a group, the fullerene is directly connected to the group.

2. The thin film solar cell according to claim 1, characterized in that: The group includes at least one of a hydroxyl group, an amino group, a carboxyl group, and a thiol group.

3. The thin film solar cell according to claim 1 or 2, characterized in that: The fullerene modified with a group is fullerol.

4. The thin film solar cell according to any one of claims 1 to 3, characterized in that: The fullerene in the fullerene modified with a group is the same as the fullerene in the material of the electron transport layer.

5. The thin film solar cell according to any one of claims 1 to 4, characterized in that: The dimension of the interface layer in the thickness direction of the thin film solar cell is smaller than the dimension of the electron transport layer in the thickness direction of the thin film solar cell, and smaller than the dimension of the oxide layer in the thickness direction of the thin film solar cell.

6. The thin film solar cell according to any one of claims 1 to 5, characterized in that: The conduction band energy level of the electron transport layer is smaller than the conduction band energy level of the light absorbing layer and larger than the conduction band energy level of the interface layer.

7. The thin film solar cell according to claim 6, characterized in that: The difference between the conduction band energy level of the electron transport layer and the conduction band energy level of the interface layer is less than 0.4 eV.

8. The thin film solar cell according to any one of claims 1 to 7, characterized in that: At least one of a surface of the interface layer facing the electron transport layer and a surface of the interface layer facing the oxide layer is an uneven surface.

9. The thin-film solar cell according to any one of claims 1 to 8, characterized in that: At least one of a surface of the interface layer facing the electron transport layer and a surface of the interface layer facing the oxide layer is provided with a groove.

10. The thin film solar cell according to claim 9, characterized in that: The groove includes an opening and a bottom wall that are relatively arranged in the thickness direction of the thin-film solar cell. In the direction from the opening to the bottom wall, the size of the groove in a first direction gradually decreases, and the first direction is perpendicular to the thickness direction of the thin-film solar cell.

11. A photovoltaic module, characterized in that: The photovoltaic module comprises a plurality of thin-film solar cells according to any one of claims 1 to 10, wherein the plurality of thin-film solar cells are connected in series.

12. A power generation device, characterized in that: The power generation equipment includes a shell and the photovoltaic assembly according to claim 11, and the photovoltaic assembly is installed in the shell.

Images